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1

Density Functional Theory Approach to Nuclear Fission  

E-Print Network (OSTI)

The Skyrme nuclear energy density functional theory (DFT) is used to model neutron-induced fission in actinides. This paper focuses on the numerical implementation of the theory. In particular, it reports recent advances in DFT code development on leadership class computers, and presents a detailed analysis of the numerical accuracy of DFT solvers for near-scission calculations.

N. Schunck

2012-12-13T23:59:59.000Z

2

Thermal Density Functional Theory in Context  

E-Print Network (OSTI)

This chapter introduces thermal density functional theory, starting from the ground-state theory and assuming a background in quantum mechanics and statistical mechanics. We review the foundations of density functional theory (DFT) by illustrating some of its key reformulations. The basics of DFT for thermal ensembles are explained in this context, as are tools useful for analysis and development of approximations. We close by discussing some key ideas relating thermal DFT and the ground state. This review emphasizes thermal DFT's strengths as a consistent and general framework.

Pribram-Jones, Aurora; Gross, E K U; Burke, Kieron

2013-01-01T23:59:59.000Z

3

MiniDFT  

NLE Websites -- All DOE Office Websites (Extended Search)

MiniDFT MiniDFT MiniDFT Description MiniDFT is a plane-wave denstity functional theory (DFT) mini-app for modeling materials. Given an set of atomic coordinates and pseudopotentials, MiniDFT computes self-consistent solutions of the Kohn-Sham equations using either the LDA or PBE exchange-correlation functionals. For each iteration of the self-consistent field cycle, the Fock matrix is constructed and then diagonalized. To build the Fock matrix, Fast Fourier Transforms are used to tranform orbitals from the plane wave basis ( where the kinetic energy is most readily compted ) to real space (where the potential is evaluated ) and back. Davidson diagonalization is used to compute the orbital energies and update the orbital coefficients. The MiniDFT mini-app was excised from the general-purpose Quantum Espresso

4

Charge transport, configuration interaction and Rydberg states under density functional theory  

E-Print Network (OSTI)

Density functional theory (DFT) is a computationally efficient formalism for studying electronic structure and dynamics. In this work, we develop DFT-based excited-state methods to study electron transport, Rydberg excited ...

Cheng, Chiao-Lun

2008-01-01T23:59:59.000Z

5

The Materials genome : rapid materials screening for renewable energy using high-throughput density functional theory  

E-Print Network (OSTI)

This thesis relates to the emerging field of high-throughput density functional theory (DFT) computation for materials design and optimization. Although highthroughput DFT is a promising new method for materials discovery, ...

Jain, Anubhav, Ph.D. Massachusetts Institute of Technology

2011-01-01T23:59:59.000Z

6

Some challenges for Nuclear Density Functional Theory  

E-Print Network (OSTI)

We discuss some of the challenges that the DFT community faces in its quest for the truly universal energy density functional applicable over the entire nuclear chart.

T. Duguet; K. Bennaceur; T. Lesinski; J. Meyer

2006-06-20T23:59:59.000Z

7

Density functional theory study of the conductivity of the biphenalenyl radical dimer  

E-Print Network (OSTI)

We present ab initio molecular calculations at different levels of density functional theory (DFT) for the spiro-biphenalenyl neurtral radical in its singlet and triplet states. We performed calculations on the dimer to ...

Lu, Aiyan

2007-01-01T23:59:59.000Z

8

Nonlinear eigenvalue problems in Density Functional Theory calculations  

SciTech Connect

Developed in the 1960's by W. Kohn and coauthors, Density Functional Theory (DFT) is a very popular quantum model for First-Principles simulations in chemistry and material sciences. It allows calculations of systems made of hundreds of atoms. Indeed DFT reduces the 3N-dimensional Schroedinger electronic structure problem to the search for a ground state electronic density in 3D. In practice it leads to the search for N electronic wave functions solutions of an energy minimization problem in 3D, or equivalently the solution of an eigenvalue problem with a non-linear operator.

Fattebert, J

2009-08-28T23:59:59.000Z

9

Density functional theory (DFT) and ab initio molecular orbital calculations have been employed to determine the structures and energies of the isomers of the OH-toluene adduct, the methyl hydroxycyclohexadienyl radical, and their corresponding transitio  

NLE Websites -- All DOE Office Websites (Extended Search)

Laboratory Investigation of Organic Aerosol Formation from Aromatic Hydrocarbons (DOE Award No. DE-FG02-02ER63098) Prepared by Luisa T. Molina, Renyi Zhang and Mario J. Molina Our work for this DOE funded project includes: (1) measurements of the kinetics and mechanism of the gas-phase oxidation reactions of the aromatic hydrocarbons initiated by OH; (2) measurements of aerosol formation from the aromatic hydrocarbons; and (3) theoretical studies to elucidate the OH-toluene reaction mechanism using quantum-chemical and rate theories. (1) Measurements of Gas-Phase Kinetics and Mechanism Work has been accomplished to develop laboratory instrumentation to conduct kinetic and mechanistic measurements of the aromatic hydrocarbon reactions initiated by OH, using

10

Recent advances in the use of density functional theory to design efficient solar energy-based renewable systems  

Science Conference Proceedings (OSTI)

This article reviews the use of Density Functional Theory (DFT) to study the electronic and optical properties of solar-active materials and dyes used in solar energy conversion applications (dye-sensitized solar cells and water splitting). We first give a brief overview of the DFT its development

Ramy Nashed; Yehea Ismail; Nageh K. Allam

2013-01-01T23:59:59.000Z

11

Communication: Density functional theory overcomes the failure of predicting intermolecular interaction energies  

Science Conference Proceedings (OSTI)

Density-functional theory (DFT) revolutionized the ability of computational quantum mechanics to describe properties of matter and is by far the most often used method. However, all the standard variants of DFT fail to predict intermolecular interaction energies. In recent years, a number of ways to go around this problem has been proposed. We show that some of these approaches can reproduce interaction energies with median errors of only about 5% in the complete range of intermolecular configurations. Such errors are comparable to typical uncertainties of wave-function-based methods in practical applications. Thus, these DFT methods are expected to find broad applications in modelling of condensed phases and of biomolecules.

Podeszwa, Rafal [Institute of Chemistry, University of Silesia, Szkolna 9, 40-006 Katowice (Poland); Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States); Szalewicz, Krzysztof [Institute of Chemistry, University of Silesia, Szkolna 9, 40-006 Katowice (Poland)

2012-04-28T23:59:59.000Z

12

Fast plane wave density functional theory molecular dynamics calculations on multi-GPU machines  

Science Conference Proceedings (OSTI)

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 ... Keywords: Density functional theory, Electronic structure, First-principles, GPU, Molecular dynamics, Plane wave pseudopotential

Weile Jia, Jiyun Fu, Zongyan Cao, Long Wang, Xuebin Chi, Weiguo Gao, Lin-Wang Wang

2013-10-01T23:59:59.000Z

13

Controlling the Electronic Properties of Nanodiamonds Via Surface Chemical Functionalization: A DFT Study  

E-Print Network (OSTI)

The electronic properties of chemically functionalized nanodiamonds are studied using density functional theory calculations. HOMO-LUMO gap and relative stabilities are calculated for different surface functionalization schemes and diamond nanocrystal morphologies. The effects of chemical decoration on the size and nature of the HOMO-LUMO gap of the various systems considered are discussed in detail. We conclude that surface chemical functionalization has the potential to become an accessible route for controlling the electronic properties of nanodiamonds.

Brown, Noam

2013-01-01T23:59:59.000Z

14

Curvature and Frontier Orbital Energies in Density Functional Theory  

SciTech Connect

Perdew et al. [Phys. Rev. Lett 49, 1691 (1982)] discovered and proved two different properties that exact Kohn-Sham density functional theory (DFT) must obey: (i) The exact total energy versus particle number must be a series of linear segments between integer electron points; (ii) Across an integer number of electrons, the exchange-correlation potential may ``jump’’ by a constant, known as the derivative discontinuity (DD). Here, we show analytically that in both the original and the generalized Kohn-Sham formulation of DFT, the two are in fact two sides of the same coin. Absence of a derivative discontinuity necessitates deviation from piecewise linearity, and the latter can be used to correct for the former, thereby restoring the physical meaning of the orbital energies. Using selected small molecules, we show that this results in a simple correction scheme for any underlying functional, including semi-local and hybrid functionals as well as Hartree-Fock theory, suggesting a practical correction for the infamous gap problem of density functional theory. Moreover, we show that optimally-tuned range-separated hybrid functionals can inherently minimize both DD and curvature, thus requiring no correction, and show that this can be used as a sound theoretical basis for novel tuning strategies.

Stein, Tamar; Autschbach, Jochen; Govind, Niranjan; Kronik, Leeor; Baer, Roi

2012-12-20T23:59:59.000Z

15

Accuracy of density functional theory in predicting formation energies of ternary oxides from binary oxides and its implication on phase stability  

E-Print Network (OSTI)

The evaluation of reaction energies between solids using density functional theory (DFT) is of practical importance in many technological fields and paramount in the study of the phase stability of known and predicted ...

Hautier, Geoffroy

16

DFT-based molecular dynamics as a new tool for computational biology: first applications and perspective  

Science Conference Proceedings (OSTI)

Static and molecular dynamics (MD) calculations based on density-functional theory (DFT) are emerging as a valuable means for simulations in the field of biology, especially when coupled with classical simulations. In this contribution, we point out ...

W. Andreoni; A. Curioni; T. Mordasini

2001-05-01T23:59:59.000Z

17

Density Functional Theory for the Photoionization Dynamics of Uracil  

E-Print Network (OSTI)

Photoionization dynamics of the RNA base Uracil is studied in the framework of Density Functional Theory (DFT). The photoionization calculations take advantage of a newly developed parallel version of a multicentric approach to the calculation of the electronic continuum spectrum which uses a set of B-spline radial basis functions and a Kohn-Sham density functional hamiltonian. Both valence and core ionizations are considered. Scattering resonances in selected single-particle ionization channels are classified by the symmetry of the resonant state and the peak energy position in the photoelectron kinetic energy scale; the present results highlight once more the site specificity of core ionization processes. We further suggest that the resonant structures previously characterized in low-energy electron collision experiments are partly shifted below threshold by the photoionization processes. A critical evaluation of the theoretical results providing a guide for future experimental work on similar biosystems.

Toffoli, D; Gianturco, F A; Lucchese, R R

2007-01-01T23:59:59.000Z

18

A DFT Approach to Non-Covalent Interactions via Monomer Polarization and Pauli Blockade  

E-Print Network (OSTI)

We propose a "DFT+dispersion" treatment which avoids double counting of dispersion terms by deriving the dispersion-free density functional theory (DFT) interaction energy and combining it with DFT-based dispersion. The formalism involves self-consistent polarization of DFT monomers restrained by the exclusion principle via the Pauli blockade technique. Any exchange-correlation potential can be used within monomers, but only the exchange operates between them. The applications to rare-gas dimers, ion-rare gas interactions and hydrogen bonds demonstrate that the interaction energies agree with benchmark values.

Rajchel, Lukasz; Szczesniak, Malgorzata M; Chalasinski, Grzegorz

2009-01-01T23:59:59.000Z

19

Density-functional theory study of gramicidin A ion channel geometry and electronic properties  

E-Print Network (OSTI)

Understanding the mechanisms underlying ion channel function from the atomic-scale requires accurate ab initio modelling as well as careful experiments. Here, we present a density functional theory (DFT) study of the ion channel gramicidin A, whose inner pore conducts only monovalent cations and whose conductance has been shown to depend on the side chains of the amino acids in the channel. We investigate the ground-state geometry and electronic properties of the channel in vacuum, focusing on their dependence on the side chains of the amino acids. We find that the side chains affect the ground state geometry, while the electrostatic potential of the pore is independent of the side chains. This study is also in preparation for a full, linear scaling DFT study of gramicidin A in a lipid bilayer with surrounding water. We demonstrate that linear scaling DFT methods can accurately model the system with reasonable computational cost. Linear scaling DFT allows ab initio calculations with 10,000 to 100,000 atoms an...

Todorovi?, Milica; Gillan, M J; Miyazaki, Tsuyoshi

2013-01-01T23:59:59.000Z

20

Accuracy of Density Functional Theory in Prediction of Carbon Dioxide Adsorbent Materials  

E-Print Network (OSTI)

We have performed a thorough computational study to assess the accuracy of density functional theory (DFT) methods in describing the interactions of CO2 with model alkali-earth-metal (AEM, Ca and Li) decorated carbon structures, namely anthracene (C14H10) molecules. We find that gas-adsorption energy and equilibrium structure results obtained with both standard (i.e. LDA and GGA) and hybrid (i.e. PBE0 and B3LYP) exchange-correlation functionals of DFT differ significantly from results obtained with second-order Moller-Plesset perturbation theory (MP2), an accurate computational quantum chemistry method. The major disagreements found can be mostly rationalized in terms of electron correlation errors that lead to inaccurate charge transfers and electrostatic Coulomb interactions between the molecules. Interestingly, we show that when the concentration of AEM atoms in anthracene is tuned to resemble as closely as possible to the electronic structure of AEM-decorated graphene, hybrid exchange-correlation DFT and ...

Cazorla, Claudio

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "functional theory dft" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Functional compression : theory and application  

E-Print Network (OSTI)

We consider the problem of functional compression. The objective is to separately compress possibly correlated discrete sources such that an arbitrary deterministic function of those sources can be computed given the ...

Doshi, Vishal D. (Vishal Devendra)

2008-01-01T23:59:59.000Z

22

Combinatorial density functional theory-based screening of surface alloys for the oxygen reduction reaction.  

DOE Green Energy (OSTI)

A density functional theory (DFT) -based, combinatorial search for improved oxygen reduction reaction (ORR) catalysts is presented. A descriptor-based approach to estimate the ORR activity of binary surface alloys, wherein alloying occurs only in the surface layer, is described, and rigorous, potential-dependent computational tests of the stability of these alloys in aqueous, acidic environments are presented. These activity and stability criteria are applied to a database of DFT calculations on nearly 750 binary transition metal surface alloys; of these, many are predicted to be active for the ORR but, with few exceptions, they are found to be thermodynamically unstable in the acidic environments typical of low-temperature fuel cells. The results suggest that, absent other thermodynamic or kinetic mechanisms to stabilize the alloys, surface alloys are unlikely to serve as useful ORR catalysts over extended periods of operation.

Greeley, J.; Norskov, J.; Center for Nanoscale Materials; Technical Univ. of Denmark

2009-03-26T23:59:59.000Z

23

Green's functions for theories with massless particles (in theory)  

E-Print Network (OSTI)

Using the method of perturbative renormalization developed by Epstein and Glaser (ibid., vol.XIX, no.3, p.211 (1973)) it is shown that Green's functions exist for theories with massless particles such as QED, and lambda : phi /sup 2n/ theories. Growth properties are given in momentum space. In the case of QED, it is also shown that one can perform the physical mass renormalization. (6 refs).

Blanchard, P

1975-01-01T23:59:59.000Z

24

The 2 1 reconstruction of the rutile TiO2(011) surface: A combined density functional theory, X-ray diffraction, and scanning  

E-Print Network (OSTI)

t An extensive search for possible structural models of the (2 Ã? 1)-reconstructed rutile TiO2(011) surface was carried out by means of density functional theory (DFT) calculations. A number of models were iden- tified that have much lower surface energies than the previously-proposed `titanyl' and `microfaceting' models

Diebold, Ulrike

25

Ferromagnetism in GaN: Gd: A density functional theory study  

SciTech Connect

First principle calculations of the electronic structure and magnetic interaction of GaN:Gd have been performed within the Generalized Gradient Approximation (GGA) of the density functional theory (DFT) with the on-site Coulomb energy U taken into account (also referred to as GGA+U). The ferromagnetic p-d coupling is found to be over two orders of magnitude larger than the s-d exchange coupling. The experimental colossal magnetic moments and room temperature ferromagnetism in GaN:Gd reported recently are explained by the interaction of Gd 4f spins via p-d coupling involving holes introduced by intrinsic defects such as Ga vacancies.

Stevenson, Cynthia; Stevenson, Cynthia

2008-02-04T23:59:59.000Z

26

Density Functional Theory Calculations of Mass Transport in UO2  

SciTech Connect

In this talk we present results of density functional theory (DFT) calculations of U, O and fission gas diffusion in UO{sub 2}. These processes all impact nuclear fuel performance. For example, the formation and retention of fission gas bubbles induce fuel swelling, which leads to mechanical interaction with the clad thereby increasing the probability for clad breach. Alternatively, fission gas can be released from the fuel to the plenum, which increases the pressure on the clad walls and decreases the gap thermal conductivity. The evolution of fuel microstructure features is strongly coupled to diffusion of U vacancies. Since both U and fission gas transport rates vary strongly with the O stoichiometry, it is also important to understand O diffusion. In order to better understand bulk Xe behavior in UO{sub 2{+-}x} we first calculate the relevant activation energies using DFT techniques. By analyzing a combination of Xe solution thermodynamics, migration barriers and the interaction of dissolved Xe atoms with U, we demonstrate that Xe diffusion predominantly occurs via a vacancy-mediated mechanism. Since Xe transport is closely related to diffusion of U vacancies, we have also studied the activation energy for this process. In order to explain the low value of 2.4 eV found for U migration from independent damage experiments (not thermal equilibrium) the presence of vacancy clusters must be included in the analysis. Next we investigate species transport on the (111) UO{sub 2} surface, which is motivated by the formation of small voids partially filled with fission gas atoms (bubbles) in UO{sub 2} under irradiation. Surface diffusion could be the rate-limiting step for diffusion of such bubbles, which is an alternative mechanism for mass transport in these materials. As expected, the activation energy for surface diffusion is significantly lower than for bulk transport. These results are further discussed in terms of engineering-scale fission gas release models. Finally, oxidation of UO{sub 2} and the importance of cluster formation for understanding thermodynamic and kinetic properties of UO{sub 2+x} are investigated.

Andersson, Anders D. [Los Alamos National Laboratory; Dorado, Boris [CEA; Uberuaga, Blas P. [Los Alamos National Laboratory; Stanek, Christopher R. [Los Alamos National Laboratory

2012-06-26T23:59:59.000Z

27

On the Accuracy of van der Waals Inclusive Density-Functional Theory Exchange-Correlation Functionals for Ice at Ambient and High Pressures  

E-Print Network (OSTI)

Density-functional theory (DFT) has been widely used to study water and ice for at least 20 years. However, the reliability of different DFT exchange-correlation (xc) functionals for water remains a matter of considerable debate. This is particularly true in light of the recent development of DFT based methods that account for van der Waals (vdW) dispersion forces. Here, we report a detailed study with several xc functionals (semi-local, hybrid, and vdW inclusive approaches) on ice Ih and six proton ordered phases of ice. Consistent with our previous study [Phys. Rev. Lett. 107, 185701 (2011)] which showed that vdW forces become increasingly important at high pressures, we find here that all vdW inclusive methods considered improve the relative energies and transition pressures of the high-pressure ice phases compared to those obtained with semi-local or hybrid xc functionals. However, we also find that significant discrepancies between experiment and the vdW inclusive approaches remain in the cohesive proper...

Santra, Biswajit; Tkatchenko, Alexandre; Alfè, Dario; Slater, Ben; Michaelides, Angelos; Car, Roberto; Scheffler, Matthias

2013-01-01T23:59:59.000Z

28

On the Accuracy of van der Waals Inclusive Density-Functional Theory Exchange-Correlation Functionals for Ice at Ambient and High Pressures  

E-Print Network (OSTI)

Density-functional theory (DFT) has been widely used to study water and ice for at least 20 years. However, the reliability of different DFT exchange-correlation (xc) functionals for water remains a matter of considerable debate. This is particularly true in light of the recent development of DFT based methods that account for van der Waals (vdW) dispersion forces. Here, we report a detailed study with several xc functionals (semi-local, hybrid, and vdW inclusive approaches) on ice Ih and six proton ordered phases of ice. Consistent with our previous study [Phys. Rev. Lett. 107, 185701 (2011)] which showed that vdW forces become increasingly important at high pressures, we find here that all vdW inclusive methods considered improve the relative energies and transition pressures of the high-pressure ice phases compared to those obtained with semi-local or hybrid xc functionals. However, we also find that significant discrepancies between experiment and the vdW inclusive approaches remain in the cohesive properties of the various phases, causing certain phases to be absent from the phase diagram. Therefore, room for improvement in the description of water at ambient and high pressures remains and we suggest that because of the stern test the high pressure ice phases pose they should be used in future benchmark studies of simulation methods for water.

Biswajit Santra; Ji?í Klimeš; Alexandre Tkatchenko; Dario Alfè; Ben Slater; Angelos Michaelides; Roberto Car; Matthias Scheffler

2013-07-12T23:59:59.000Z

29

A density functional theory and time-dependent density functional theory investigation on the anchor comparison of triarylamine-based dyes  

SciTech Connect

To understand the effects of the anchor part in organic dyes on the energy conversion efficiency of dye-sensitized solar cells (DSCs), two different anchor groups used in metal-free triphenylamine (TPA)-based organic dyes for DSCs have been theoretically compared. Density functional theory (DFT) and time-dependent DFT (TDDFT) study of geometry properties, excitations, and electronic structures of triarylamine-based dyes (TC1 and TPAR1) before and after binding to titanium has been performed under the level of TD-PBE1PBE/6-311G(d,p)//B3LYP/6-311G(d,p). The result shows that cyanoacrylic acid anchor favors better photoelectrochemical properties of DSCs than that of rhodanine-3-acetic acid anchor via providing more shift of TiO{sub 2} conduction band toward the vacuum energy levels (larger open circuit potentials) and more favorable conjugation with titanium. This study is expected to shed light on the design of metal-free organic dyes for DSCs.

Peng Bo; Yang Siqi; Li Lanlan; Cheng Fangyi; Chen Jun [Institute of New Energy Material Chemistry and Key Laboratory of Energy-Material Chemistry, Chemistry College, Nankai University, Tianjin 300071 (China)

2010-01-21T23:59:59.000Z

30

Parallel Implementation of Gamma-Point Pseudopotential Plane-Wave DFT with Exact Exchange  

Science Conference Proceedings (OSTI)

One of the more persistent failures of conventional density functional theory (DFT) methods has been their failure to yield localized charge states such as polarons, excitons and solitons in solid-state and extended systems. It has been suggested that conventional DFT functionals, which are not self-interaction free, tend to favor delocalized electronic states since self-interaction creates a Coulomb barrier to charge localization. Pragmatic approaches in which the exchange correlation functionals are augmented with small amount of exact exchange (hybrid-DFT, e.g. B3LYP and PBE0) have shown promise in localizing charge states and predicting accurate band gaps and reaction barriers. We have developed a parallel algorithm for implementing exact exchange into pseudopotential plane-wave density functional theory and we have implemented it in the NWChem program package. The technique developed can readily be employed in plane-wave DFT programs. Furthermore, atomic forces and stresses are straightforward to implement, making it applicable to both confined and extended systems, as well as to Car-Parrinello ab initio molecular dynamic simulations. This method has been applied to several systems for which conventional DFT methods do not work well, including calculations for band gaps in oxides and the electronic structure of a charge trapped state in the Fe(II) containing mica, annite.

Bylaska, Eric J.; Tsemekhman, Kiril L.; Baden, Scott B.; Weare, John H.; Jonsson, Hannes

2011-01-15T23:59:59.000Z

31

Nuclear fission in covariant density functional theory  

E-Print Network (OSTI)

The current status of the application of covariant density functional theory to microscopic description of nuclear fission with main emphasis on superheavy nuclei (SHN) is reviewed. The softness of SHN in the triaxial plane leads to an emergence of several competing fission pathes in the region of the inner fission barrier in some of these nuclei. The outer fission barriers of SHN are considerably affected both by triaxiality and octupole deformation.

A. V. Afanasjev; H. Abusara; P. Ring

2013-09-12T23:59:59.000Z

32

Symmetry energy in nuclear density functional theory  

E-Print Network (OSTI)

The nuclear symmetry energy represents a response to the neutron-proton asymmetry. In this survey we discuss various aspects of symmetry energy in the framework of nuclear density functional theory, considering both non-relativistic and relativistic self-consistent mean-field realizations side-by-side. Key observables pertaining to bulk nucleonic matter and finite nuclei are reviewed. Constraints on the symmetry energy and correlations between observables and symmetry-energy parameters, using statistical covariance analysis, are investigated. Perspectives for future work are outlined in the context of ongoing experimental efforts.

W. Nazarewicz; P. -G. Reinhard; W. Satula; D. Vretenar

2013-07-22T23:59:59.000Z

33

Symmetry energy in nuclear density functional theory  

E-Print Network (OSTI)

The nuclear symmetry energy represents a response to the neutron-proton asymmetry. In this survey we discuss various aspects of symmetry energy in the framework of nuclear density functional theory, considering both non-relativistic and relativistic self-consistent mean-field realizations side-by-side. Key observables pertaining to bulk nucleonic matter and finite nuclei are reviewed. Constraints on the symmetry energy and correlations between observables and symmetry-energy parameters, using statistical covariance analysis, are investigated. Perspectives for future work are outlined in the context of ongoing experimental efforts.

Nazarewicz, W; Satula, W; Vretenar, D

2013-01-01T23:59:59.000Z

34

Theory and Computation | Center for Functional Nanomaterials  

NLE Websites -- All DOE Office Websites (Extended Search)

Theory and Computation theory and computation Flexible computational infrastructure, software tools and theoretical consultation are provided to support modeling and understanding...

35

Hexakis(4-phormylphenoxy)cyclotriphosphazene: X-ray and DFT-calculated structures  

SciTech Connect

The crystal structure of hexakis(4-phormylphenoxy)cyclotriphosphazene is determined by using X-ray diffraction and then the molecular structure is investigated with density functional theory (DFT). X-Ray study shows that the title compound has C-H-{pi} interaction with phosphazene ring. The molecules in the unit cell are packed with Van der Waals and dipole-dipole interactions and the molecules are packed in zigzag shaped. Optimized molecular geometry is calculated with DFT at B3LYP/6-311G(d,p) level. The results from both experimental and theoretical calculations are compared in this study.

Albayrak, Cigdem, E-mail: calbayrak@sinop.edu.tr; Kosar, Basak [Sinop University, Faculty of Education (Turkey); Odabasoglu, Mustafa [Pamukkale University, Chemical Technology Program (Turkey); Bueyuekguengoer, Orhan [Ondokuz Mayis University, Faculty of Arts and Sciences (Turkey)

2010-12-15T23:59:59.000Z

36

Helium under high pressure: A comparative study of all-electron and pseudopotential methods within density functional theory  

E-Print Network (OSTI)

We have calculated the ground state electronic structure of He under pressure from 0 to 1500 GPa using both all-electron full-potential and pseudopotential methods based on the density functional theory (DFT). We find that throughout this pressure range, pseudopotentials yield essentially the same energy-volume curve for all of bcc, fcc, and hcp configurations as does the full-potential method, a strong indication that pseudopotential approximation works well for He both as the common element in some giant planets and as detrimental impurities in fusion reactor materials. The hcp lattice is always the most stable structure and bcc the least stable one. Since the energy preference of hcp over fcc and bcc is within 0.01 eV below 100 GPa and about 0.1 eV at 1500 GPa, on the same order of the error bar in local or semi-local density approximations in DFT, phase transitions can only be discussed with more precise description of electron correlation in Quantum Monte Carlo or DFT-based GW methods.

Xiao, W; Geng, W T

2012-01-01T23:59:59.000Z

37

New density functional theory approaches for enabling prediction of chemical and physical properties of plutonium and other actinides.  

SciTech Connect

Density Functional Theory (DFT) based Equation of State (EOS) construction is a prominent part of Sandia's capabilities to support engineering sciences. This capability is based on amending experimental data with information gained from computational investigations, in parts of the phase space where experimental data is hard, dangerous, or expensive to obtain. A prominent materials area where such computational investigations are hard to perform today because of limited accuracy is actinide and lanthanide materials. The Science of Extreme Environment Lab Directed Research and Development project described in this Report has had the aim to cure this accuracy problem. We have focused on the two major factors which would allow for accurate computational investigations of actinide and lanthanide materials: (1) The fully relativistic treatment needed for materials containing heavy atoms, and (2) the needed improved performance of DFT exchange-correlation functionals. We have implemented a fully relativistic treatment based on the Dirac Equation into the LANL code RSPt and we have shown that such a treatment is imperative when calculating properties of materials containing actinides and/or lanthanides. The present standard treatment that only includes some of the relativistic terms is not accurate enough and can even give misleading results. Compared to calculations previously considered state of the art, the Dirac treatment gives a substantial change in equilibrium volume predictions for materials with large spin-orbit coupling. For actinide and lanthanide materials, a Dirac treatment is thus a fundamental requirement in any computational investigation, including those for DFT-based EOS construction. For a full capability, a DFT functional capable of describing strongly correlated systems such as actinide materials need to be developed. Using the previously successful subsystem functional scheme developed by Mattsson et.al., we have created such a functional. In this functional the Harmonic Oscillator Gas is providing the necessary reference system for the strong correlation and localization occurring in actinides. Preliminary testing shows that the new Hao-Armiento-Mattsson (HAM) functional gives a trend towards improved results for the crystalline copper oxide test system we have chosen. This test system exhibits the same exchange-correlation physics as the actinide systems do, but without the relativistic effects, giving access to a pure testing ground for functionals. During the work important insights have been gained. An example is that currently available functionals, contrary to common belief, make large errors in so called hybridization regions where electrons from different ions interact and form new states. Together with the new understanding of functional issues, the Dirac implementation into the RSPt code will permit us to gain more fundamental understanding, both quantitatively and qualitatively, of materials of importance for Sandia and the rest of the Nuclear Weapons complex.

Mattsson, Ann Elisabet

2012-01-01T23:59:59.000Z

38

Dynamical density functional theory for dense atomic liquids  

E-Print Network (OSTI)

Starting from Newton's equations of motion, we derive a dynamical density functional theory (DDFT) applicable to atomic liquids. The theory has the feature that it requires as input the Helmholtz free energy functional from equilibrium density functional theory. This means that, given a reliable equilibrium free energy functional, the correct equilibrium fluid density profile is guaranteed. We show that when the isothermal compressibility is small, the DDFT generates the correct value for the speed of sound in a dense liquid. We also interpret the theory as a dynamical equation for a coarse grained fluid density and show that the theory can be used (making further approximations) to derive the standard mode coupling theory that is used to describe the glass transition. The present theory should provide a useful starting point for describing the dynamics of inhomogeneous atomic fluids.

A. J. Archer

2006-04-25T23:59:59.000Z

39

First-Principles Density Functional Theory Study of Grain Boundary ...  

Science Conference Proceedings (OSTI)

Presentation Title, First-Principles Density Functional Theory Study of Grain ... It was found that both the vacancy formation energy and diffusion activation ...

40

The Materials Project: Combining Density Functional Theory Calculation...  

NLE Websites -- All DOE Office Websites (Extended Search)

The Materials Project The Materials Project: Combining Density Functional Theory Calculations with Supercomputing Centers for New Materials Discovery May 2, 2013 jain2 Anubhav Jain...

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While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Parabolic Whittaker Functions and Topological Field Theories I  

E-Print Network (OSTI)

First, we define a generalization of the standard quantum Toda chain inspired by a construction of quantum cohomology of partial flags spaces GL(\\ell+1)/P, P a parabolic subgroup. Common eigenfunctions of the parabolic quantum Toda chains are generalized Whittaker functions given by matrix elements of infinite-dimensional representations of gl(\\ell+1). For maximal parabolic subgroups (i.e. for P such that GL(\\ell+1)/P=\\mathbb{P}^{\\ell}) we construct two different representations of the corresponding parabolic Whittaker functions as correlation functions in topological quantum field theories on a two-dimensional disk. In one case the parabolic Whittaker function is given by a correlation function in a type A equivariant topological sigma model with the target space \\mathbb{P}^{\\ell}. In the other case the same Whittaker function appears as a correlation function in a type B equivariant topological Landau-Ginzburg model related with the type A model by mirror symmetry. This note is a continuation of our project of establishing a relation between two-dimensional topological field theories (and more generally topological string theories) and Archimedean (\\infty-adic) geometry. From this perspective the existence of two, mirror dual, topological field theory representations of the parabolic Whittaker functions provide a quantum field theory realization of the local Archimedean Langlands duality for Whittaker functions. The established relation between the Archimedean Langlands duality and mirror symmetry in two-dimensional topological quantum field theories should be considered as a main result of this note.

Anton Gerasimov; Dimitri Lebedev; Sergey Oblezin

2010-02-12T23:59:59.000Z

42

Hybrid Dynamic Density Functional Theory for Polymer Melts and Blends  

E-Print Network (OSTI)

We propose a high-speed and accurate hybrid dynamic density functional theory for the computer simulations of the phase separation processes of polymer melts and blends. The proposed theory is a combination of the dynamic self-consistent field (SCF) theory and a time-dependent Ginzburg-Landau type theory with the random phase approximation (GRPA). The SCF theory is known to be accurate in evaluating the free energy of the polymer systems in both weak and strong segregation regions although it has a disadvantage of the requirement of a considerable amount of computational cost. On the other hand, the GRPA theory has an advantage of much smaller amount of required computational cost than the SCF theory while its applicability is limited to the weak segregation region. To make the accuracy of the SCF theory and the high-performance of the GRPA theory compatible, we adjust the chemical potential of the GRPA theory by using the SCF theory every constant time steps in the dynamic simulations. The performance of the GRPA and the hybrid theories is tested by using several systems composed of an A/B homopolymer, an AB diblock copolymer, or an ABC triblock copolymer. Using the hybrid theory, we succeeded in reproducing the metastable complex phase-separated domain structures of an ABC triblock copolymer observed by experiments.

Takashi Honda; Toshihiro Kawakatsu

2006-09-05T23:59:59.000Z

43

Tb0.5Bi0.5MnO3: New material. A DFT study  

Science Conference Proceedings (OSTI)

In the present work we have determined the band structure and the densities of states (DOS) of Tb0.5Bi0.5MnO3 in cubic phase using the density functional theory (DFT). The determination of the lattice constant was ... Keywords: 61.50.-f, 62.20.-x, 71.15.Nc, 71.20.-b, 71.55.Ht, 75.20.En, Band structure, DFT, Density of states, Magnetic properties, Mechanical and structural properties, Tb1-xBixMnO3

Miguel Grizalez; M. Jairo Arbey Rodríguez; Jesús Heiras; P. Prieto

2008-03-01T23:59:59.000Z

44

Constrained Density-Functional Theory--Configuration Interaction  

E-Print Network (OSTI)

In this thesis, I implemented a method for performing electronic structure calculations, "Constrained Density Functional Theory-- Configuration Interaction" (CDFT-CI), which builds upon the computational strengths of Density ...

Kaduk, Benjamin James

2012-01-01T23:59:59.000Z

45

Density Functional Theory with Dissipation: Transport through Single Molecules  

SciTech Connect

A huge amount of fundamental research was performed on this grant. Most of it focussed on fundamental issues of electronic structure calculations of transport through single molecules, using density functional theory. Achievements were: (1) First density functional theory with dissipation; (2) Pseudopotential plane wave calculations with master equation; (3) Weak bias limit; (4) Long-chain conductance; and (5) Self-interaction effects in tunneling.

Kieron Burke

2012-04-30T23:59:59.000Z

46

Exact-exchange density functional theory for neutron drops  

Science Conference Proceedings (OSTI)

We compute the ground-state properties of finite systems of neutrons in an external harmonic trap, interacting via the Minnesota potential, using the ''exact-exchange'' form of orbital-dependent density functional theory. We compare our results with Hartree-Fock calculations and find very close agreement. Within the context of the interaction studied, we conclude that this simple orbital-dependent functional brings conventional nuclear density functional theory to the level of Hartree-Fock in an ab initio fashion. Our work is a first step toward higher order ab initio nuclear functionals based on realistic nucleon-nucleon interactions.

Drut, Joaquin E. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545-0001 (United States); Department of Physics, Ohio State University, Columbus, Ohio 43210-1117 (United States); Platter, Lucas [Fundamental Physics, Chalmers University of Technology, SE-41296 Goeteborg (Sweden); Institute for Nuclear Theory, University of Washington, Seattle, Washington 98195 (United States); Department of Physics, Ohio State University, Columbus, Ohio 43210-1117 (United States)

2011-07-15T23:59:59.000Z

47

Test Functions Space in Noncommutative Quantum Field Theory  

E-Print Network (OSTI)

It is proven that the $\\star$-product of field operators implies that the space of test functions in the Wightman approach to noncommutative quantum field theory is one of the Gel'fand-Shilov spaces $S^{\\beta}$ with $\\beta test functions smears the noncommutative Wightman functions, which are in this case generalized distributions, sometimes called hyperfunctions. The existence and determination of the class of the test function spaces in NC QFT is important for any rigorous treatment in the Wightman approach.

M. Chaichian; M. Mnatsakanova; A. Tureanu; Yu. Vernov

2007-06-12T23:59:59.000Z

48

Correlation Testing in Nuclear Density Functional Theory  

E-Print Network (OSTI)

Correlation testing provides a quick method of discriminating amongst potential terms to include in a nuclear mass formula or functional and is a necessary tool for further nuclear mass models; however a firm mathematical foundation of the method has not been previously set forth. Here, the necessary justification for correlation testing is developed and more detail of the motivation behind its use is give. Examples are provided to clarify the method analytically and for computational benchmarking. We provide a quantitative demonstration of the method's performance and short-comings, highlighting also potential issues a user may encounter. In concluding we suggest some possible future developments to improve the limitations of the method.

M. G. Bertolli

2012-08-07T23:59:59.000Z

49

Quantifying the importance of orbital over spin correlations in delta-Pu within density-functional theory  

SciTech Connect

Spin and orbital and electron correlations are known to be important when treating the high-temperature {delta} phase of plutonium within the framework of density-functional theory (DFT). One of the more successful attempts to model {delta}-Pu within this approach has included condensed-matter generalizations of Hund's three rules for atoms, i.e., spin polarization, orbital polarization, and spin-orbit coupling. Here they perform a quantitative analysis of these interactions relative rank for the bonding and electronic structure in {delta}-Pu within the DFT model. The result is somewhat surprising in that spin-orbit coupling and orbital polarization are far more important than spin polarization for a realistic description of {delta}-Pu. They show that these orbital correlations on their own, without any formation of magnetic spin moments, can account for the low atomic density of the {delta} phase with a reasonable equation-of-state. In addition, this unambiguously non-magnetic (NM) treatment produces a one-electron spectra with resonances close to the Fermi level consistent with experimental valence band photoemission spectra.

Soderlind, P; Wolfer, W

2007-07-27T23:59:59.000Z

50

Restoration of the Derivative Discontinuity in Kohn-Sham Density Functional Theory: An Efficient Scheme for Energy Gap Correction  

E-Print Network (OSTI)

From the perspective of perturbation theory, we propose a systematic procedure for the evaluation of the derivative discontinuity (DD) of the exchange-correlation energy functional in Kohn-Sham density functional theory (KS-DFT), wherein the exact DD can in principle be obtained by summing up all the perturbation corrections to infinite order. Truncation of the perturbation series at low order yields an efficient scheme for obtaining the approximate DD. While the zeroth-order theory yields a vanishing DD, the first-order correction to the DD can be expressed as an explicit universal functional of the ground-state density and the KS lowest unoccupied molecular orbital density, allowing the direct evaluation of the DD in the standard KS method without extra computational cost. The fundamental gap can be predicted by adding the estimated DD to the KS gap. This scheme is shown to be accurate in the prediction of the fundamental gaps for a wide variety of atoms and molecules.

Jeng-Da Chai; Po-Ta Chen

2012-11-03T23:59:59.000Z

51

The benchmark of gutzwiller density functional theory in hydrogen systems  

SciTech Connect

We propose an approximate form of the exchange-correlation energy functional for the Gutzwiller density functional theory. It satisfies certain physical constraints in both weak and strong electron correlation limits. We benchmark the Gutzwiller density functional approximation in the hydrogen systems, where the static correlation error is shown to be negligible. The good transferability is demonstrated by applications to the hydrogen molecule and some crystal structures.

Yao, Y.; Wang, Cai-Zhuang; Ho, Kai-Ming

2012-02-23T23:59:59.000Z

52

Density functional theory and optimal transportation with Coulomb cost  

E-Print Network (OSTI)

We present here novel insight into exchange-correlation functionals in density functional theory, based on the viewpoint of optimal transport. We show that in the case of two electrons and in the semiclassical limit, the exact exchange-correlation functional reduces to a very interesting functional of novel form, which depends on an optimal transport map $T$ associated with a given density $\\rho$. Since the above limit is strongly correlated, the limit functional yields insight into electron correlations. We prove the existence and uniqueness of such an optimal map for any number of electrons and each $\\rho$, and determine the map explicitly in the case when $\\rho$ is radially symmetric.

Codina Cotar; Gero Friesecke; Claudia Klüppelberg

2011-04-04T23:59:59.000Z

53

Carbon dioxide adsorption and activation on Ceria (110): A density functional theory study  

E-Print Network (OSTI)

Ceria (CeO2) is a promising catalyst for the reduction of carbon dioxide (CO2) to liquid fuels and commodity chemicals, in part because of its high oxygen storage capacity, yet the fundamentals of CO2 adsorption and initial activation on CeO2 surfaces remain largely unknown. We use density functional theory, corrected for onsite Coulombic interactions (DFT+U), to explore various adsorption sites and configurations for CO2 on stoichiometric and reduced CeO2 (110). Our model of reduced CeO2 (110) contains oxygen vacancies at the topmost atomic layer and undergoes surface reconstruction upon introduction of these vacancies. We find that CO2 adsorption on reduced CeO2 (110) is thermodynamically favored over the corresponding adsorption on stoichiometric CeO2 (110). The most stable adsorption configuration consists of CO2 adsorbed parallel to the reduced CeO2 (110) surface, with the molecule situated near the site of the oxygen vacancy. Structural changes in the CO2 molecule are also observed upon adsorption, so t...

Cheng, Zhuo; Lo, Cynthia S

2012-01-01T23:59:59.000Z

54

Improved association in a classical density functional theory for water  

E-Print Network (OSTI)

We present a modification to our recently published SAFT-based classical density functional theory for water. We have recently developed and tested a functional for the averaged radial distribution function at contact of the hard-sphere fluid that is dramatically more accurate at interfaces than earlier approximations. We now incorporate this improved functional into the association term of our free energy functional for water, improving its description of hydrogen bonding. We examine the effect of this improvement by studying two hard solutes: a hard hydrophobic rod and a hard sphere. The improved functional leads to a moderate change in the density profile and a large decrease in the number of hydrogen bonds broken in the vicinity of the solutes.We present a modification to our recently published SAFT-based classical density functional theory for water. We have recently developed and tested a functional for the averaged radial distribution function at contact of the hard-sphere fluid that is dramatically more accurate at interfaces than earlier approximations. We now incorporate this improved functional into the association term of our free energy functional for water, improving its description of hydrogen bonding. We examine the effect of this improvement by studying two hard solutes: a hard hydrophobic rod and a hard sphere. The improved functional leads to a moderate change in the density profile and a large decrease in the number of hydrogen bonds broken in the vicinity of the solutes.

Eric J. Krebs; Jeff B. Schulte; David Roundy

2013-09-07T23:59:59.000Z

55

Oxygen Reduction Reaction on Dispersed and Core-Shell Metal Alloy Catalysts: Density Functional Theory Studies  

E-Print Network (OSTI)

Pt-based alloy surfaces are used to catalyze the electrochemical oxygen reduction reaction (ORR), where molecular oxygen is converted into water on fuel cell electrodes. In this work, we address challenges due to the cost of high Pt loadings in the cathode electrocatalyst, as well as those arising from catalyst durability. We aim to develop an increased understanding of the factors that determine ORR activity together with stability against surface segregation and dissolution of Pt-based alloys. We firstly focus on the problem of determining surface atomic distribution resulting from surface segregation phenomena. We use first-principles density functional theory (DFT) calculations on PtCo and Pt3Co overall compositions, as well as adsorption of water and atomic oxygen on PtCo(111) and Pt-skin structures. The bonding between water and surfaces of PtCo and Pt-skin monolayers are investigated in terms of orbital population. Also, on both surfaces, the surface reconstruction effect due to high oxygen coverage and water co-adsorption is investigated. Although the PtCo structures show good activity, a large dissolution of Co atoms tends to occur in acid medium. To tackle this problem, we examine core-shell structures which showed improved stability and activity compared to Pt(111), in particular, one consisting of a surface Pt-skin monolayer over an IrCo or Ir3Co core, with or without a Pd interlayer between the Pt surface and the Ir-Co core. DFT analysis of surface segregation, surface stability against dissolution, surface Pourbaix diagrams, and reaction mechanisms provide useful predictions on catalyst durability, onset potential for water oxidation, surface atomic distribution, coverage of oxygenated species, and activity. The roles of the Pd interlayer in the core-shell structures that influence higher ORR activity are clarified. Furthermore, the stability and activity enhancement of new shell-anchor-core structures of Pt/Fe-C/core, Pt/Co-C/core and Pt/Ni-C/core are demonstrated with core materials of Ir, Pd3Co, Ir3Co, IrCo and IrNi. Based on the analysis, Pt/Fe-C/Ir, Pt/Co-C/Ir, Pt/Ni-C/Ir, Pt/Co-C/Pd3Co, Pt/Fe-C/Pd3Co, Pt/Co- C/Ir3Co, Pt/Fe-C/Ir3Co, Pt/Co-C/IrCo, Pt/Co-C/IrNi, and Pt/Fe-C/IrNi structures show promise in terms of both improved durability and relatively high ORR activity.

Hirunsit, Pussana

2010-08-01T23:59:59.000Z

56

A DFT investigation of methanolysis and hydrolysis of triacetin  

E-Print Network (OSTI)

The thermodynamic and kinetic aspects of the methanolysis and hydrolysis reactions of glycerol triacetate or triacetin, a model triacylglycerol compound, were investigated by using Density Functional Theory (DFT) at the B3LYP/6-31++G(d,p) level of calculation. Twelve elementary steps of triacetin methanolysis were studied under acid-catalyzed and base-catalyzed conditions. The mechanism of acid-catalyzed methanolysis reaction which has not been reported yet for any esters was proposed. The effects of substitution, methanolysis/hydrolysis position, solvent and face of nucleophilic attack on the free energy of reaction and activation energy were examined. The prediction confirmed the facile position at the middle position of glycerol observed by NMR techniques. The calculated activation energy and the trends of those factors agree with existing experimental observations in biodiesel production.

Limpanuparb, Taweetham; Tantirungrotechai, Yuthana; 10.1016/j.theochem.2010.05.022

2012-01-01T23:59:59.000Z

57

Session #1: Cutting Edge Methodologies--Beyond Current DFT  

NLE Websites -- All DOE Office Websites (Extended Search)

Session #1: Cutting Edge Methodologies (beyond Current DFT) Moderator: Shengbai Zhang (RPI/ REL) Topics to be addressed: Benchmarking state-of-the-art approaches, accurate energy landscape. Identify problems with the current DFT-LDA and GGA approaches and possible pathways to overcome these problems. PBE PBE How Bad is DFT for vdW Interactions? fcc Ar Benzene dimer PBE LDA Exp CCSD(T) LDA PBE vdW Interaction between H 2 and Carbon � PBE Graphene CCSD(T) LDA Benzene omitted in the LDA and GGA van der Walls (vdW)-DFT: Langreth, Kohn � Fully nonlocal � functional: � � Long-range nonlocal correlation energy functional (omitted in the LDA and GGA) ) ( � Computational cost considerably more than GGA � Added as post-GGA energy correction but force

58

Decision Support with Belief Functions Theory for Seabed Characterization  

E-Print Network (OSTI)

The seabed characterization from sonar images is a very hard task because of the produced data and the unknown environment, even for an human expert. In this work we propose an original approach in order to combine binary classifiers arising from different kinds of strategies such as one-versus-one or one-versus-rest, usually used in the SVM-classification. The decision functions coming from these binary classifiers are interpreted in terms of belief functions in order to combine these functions with one of the numerous operators of the belief functions theory. Moreover, this interpretation of the decision function allows us to propose a process of decisions by taking into account the rejected observations too far removed from the learning data, and the imprecise decisions given in unions of classes. This new approach is illustrated and evaluated with a SVM in order to classify the different kinds of sediment on image sonar.

Martin, Arnaud

2008-01-01T23:59:59.000Z

59

Recent developments in classical density functional theory: Internal energy functional and diagrammatic structure of fundamental measure theory  

E-Print Network (OSTI)

An overview of several recent developments in density functional theory for classical inhomogeneous liquids is given. We show how Levy's constrained search method can be used to derive the variational principle that underlies density functional theory. An advantage of the method is that the Helmholtz free energy as a functional of a trial one-body density is given as an explicit expression, without reference to an external potential as is the case in the standard Mermin-Evans proof by reductio ad absurdum. We show how to generalize the approach in order to express the internal energy as a functional of the one-body density distribution and of the local entropy distribution. Here the local chemical potential and the bulk temperature play the role of Lagrange multipliers in the Euler-Lagrange equations for minimiziation of the functional. As an explicit approximation for the free-energy functional for hard sphere mixtures, the diagrammatic structure of Rosenfeld's fundamental measure density unctional is laid out. Recent extensions, based on the Kierlik-Rosinberg scalar weight functions, to binary and ternary non-additive hard sphere mixtures are described.

M. Schmidt; M. Burgis; W. S. B. Dwandaru; G. Leithall; P. Hopkins

2012-12-27T23:59:59.000Z

60

Multiloop World-Line Green Functions from String Theory  

E-Print Network (OSTI)

We show how the multiloop bosonic Green function of closed string theory reduces to the world-line Green function as defined by Schmidt and Schubert in the limit where the string world-sheet degenerates into a $\\Phi^3$ particle diagram. To obtain this correspondence we have to make an appropriate choice of the local coordinates defined on the degenerate string world sheet. We also present a set of simple rules that specify, in the explicit setting of the Schottky parametrization, which is the corner of moduli space corresponding to a given multiloop $\\Phi^3$ diagram.

Kaj Roland; Haru-Tada Sato

1996-04-24T23:59:59.000Z

Note: This page contains sample records for the topic "functional theory dft" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Understanding of Ethanol Decomposition on Rh(111) From Density Functional Theory and Kinetic Monte Carlo Simulations  

DOE Green Energy (OSTI)

Reaction mechanisms of ethanol decomposition on Rh(1 1 1) were elucidated by means of periodic density functional theory (DFT) calculations and kinetic Monte Carlo (KMC) simulations. We propose that the most probable reaction pathway is via CH{sub 3}CH{sub 2}O* on the basis of our mechanistic study: CH{sub 3}CH{sub 2}OH* {yields} CH{sub 3}CH{sub 2}O* {yields} CH{sub 2}CH{sub 2}O* {yields} CH{sub 2}CHO* {yields} CH{sub 2}CO* {yields} CHCO* {yields} CH* + CO* {yields} C* + CO*. In contrast, the contribution from the pathway via CH{sub 3}CHOH* is relatively small, CH{sub 3}CH{sub 2}OH* {yields} CH{sub 3}CHOH* {yields} CH{sub 3}CHO* {yields} CH{sub 3}CO* {yields} CH{sub 2}CO* {yields} CHCO* {yields} CH* + CO* {yields} C* + CO*. According to our calculations, one of the slow steps is the formation of the oxametallacycle CH{sub 2}CH{sub 2}O* species, which leads to the production of CHCO*, the precursor for C-C bond breaking. Finally, the decomposition of ethanol leads to the production of C and CO. Our calculations, for ethanol combustion on Rh, the major obstacle is not C-C bond cleavage, but the C contamination on Rh(1 1 1). The strong C-Rh interaction may deactivate the Rh catalyst. The formation of Rh alloys with Pt and Pd weakens the C-Rh interaction, easing the removal of C, and, as expected, in accordance with the experimental findings, facilitating ethanol combustion.

Liu, P.; Choi, Y.M.

2011-05-16T23:59:59.000Z

62

Nuclear Density Functional Theory and the Equation of State  

E-Print Network (OSTI)

A nuclear density functional can be used to find the binding energy and shell structure of nuclei and the energy gap in superconducting nuclear matter. In this paper, we study the possible application of a nuclear density functional theory to nuclear astrophysics. From energy density functional theory, we can deduce the interaction between nucleons to find a rough estimate of the charge radius of the specific nuclei. Compared to the Finite-Range Thomas Fermi model, we include three-body forces, which might be important at densities several times that of nuclear matter density. We also add the momentum dependent interaction to take into account the effective mass of the nucleons. We study matter in the neutron star crust using the Wigner-Seitz cell method. By constructing the mass-radius relation of neutron stars and investigating lepton-rich nuclear matter in proto-neutron stars, we find that the density functional can be used to construct an equation of state of hot dense matter.

Yeunhwan Lim

2011-04-06T23:59:59.000Z

63

Nuclear Density Functional Theory and the Equation of State  

E-Print Network (OSTI)

A nuclear density functional can be used to find the binding energy and shell structure of nuclei and the energy gap in superconducting nuclear matter. In this paper, we study the possible application of a nuclear density functional theory to nuclear astrophysics. From energy density functional theory, we can deduce the interaction between nucleons to find a rough estimate of the charge radius of the specific nuclei. Compared to the Finite-Range Thomas Fermi model, we include three-body forces, which might be important at densities several times that of nuclear matter density. We also add the momentum dependent interaction to take into account the effective mass of the nucleons. We study matter in the neutron star crust using the Wigner-Seitz cell method. By constructing the mass-radius relation of neutron stars and investigating lepton-rich nuclear matter in proto-neutron stars, we find that the density functional can be used to construct an equation of state of hot dense matter.

Lim, Yeunhwan

2011-01-01T23:59:59.000Z

64

Beyond the Gas Phase: Towards Modeling Bulk Ionic Liquids with a Comparison of Density Functional Tight Binding (DFTB) to Density Functional Theory (DFT).  

E-Print Network (OSTI)

??Coal-fired power plants are a leading contributor to the increase in CO2 released into the atmosphere. Alkanolamines are considered a potential solvent to capture this… (more)

Danser, Mandelle Ann

2010-01-01T23:59:59.000Z

65

(E)-2-[(2-Bromophenylimino)methyl]-5-methoxyphenol: X-ray and DFT-calculated structures  

SciTech Connect

The crystal structure of (E)-2-[(2-Bromophenylimino)methyl]-5-methoxyphenol is determined by using X-ray diffraction and then the molecular structure is investigated with density functional theory (DFT). X-Ray study shows that the title compound has a strong intramolecular O-H-N hydrogen bond and three dimensional crystal structure is primarily determined by C-H-{pi} and weak van der Waals interactions. The strong O-H-N bond is an evidence of the preference for the phenol-imine tautomeric form in the solid state. Optimized molecular geometry is calculated with DFT at the B3LYP/6-31G(d,p) level. The IR spectra of compound were recorded experimentally and calculated to compare with each other. The results from both experiment and theoretical calculations are compared in this study.

Kosar, B., E-mail: bkosar@omu.edu.tr; Albayrak, C. [Sinop University, Faculty of Education (Turkey); Odabasoglu, M. [Pamukkale University, Chemistry Program (Turkey); Bueyuekguengoer, O. [Ondokuz Mayis University, Faculty of Arts and Sciences (Turkey)

2010-12-15T23:59:59.000Z

66

Fragment-based Time-dependent Density-functional Theory  

E-Print Network (OSTI)

Using the Runge-Gross theorem that establishes the foundation of Time-dependent Density Functional Theory (TDDFT) we prove that for a given electronic Hamiltonian, choice of initial state, and choice of fragmentation, there is a unique single-particle potential (dubbed time-dependent partition potential) which, when added to each of the pre-selected fragment potentials, forces the fragment densities to evolve in such a way that their sum equals the exact molecular density at all times. This uniqueness theorem suggests new ways of computing time-dependent properties of electronic systems via fragment-TDDFT calculations. We derive a formally exact relationship between the partition potential and the total density, and illustrate our approach on a simple model system for binary fragmentation in a laser field.

Mosquera, Martin A; Wasserman, Adam

2013-01-01T23:59:59.000Z

67

Optimized local basis set for Kohn-Sham density functional theory  

Science Conference Proceedings (OSTI)

We develop a technique for generating a set of optimized local basis functions to solve models in the Kohn-Sham density functional theory for both insulating and metallic systems. The optimized local basis functions are obtained by solving a minimization ... Keywords: Discontinuous Galerkin, Electronic structure, GMRES, Kohn-Sham density functional theory, Molecular dynamics, Optimized local basis set, Preconditioning, Pulay force, Trace minimization

Lin Lin; Jianfeng Lu; Lexing Ying; Weinan E

2012-05-01T23:59:59.000Z

68

Subspace accelerated inexact Newton method for large scale wave functions calculations in Density Functional Theory  

SciTech Connect

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.

Fattebert, J

2008-07-29T23:59:59.000Z

69

Ru L[subscript 2,3] XANES theoretical simulation with DFT: A test of the core-hole treatment  

SciTech Connect

Density functional theory (DFT)-based relativistic calculations were performed to model the Ru L-edge X-ray absorption near edge structure (XANES) spectra of the hexaammineruthenium complex [Ru(NH{sub 3}){sub 6}]{sup 3+} and 'blue dimer' water oxidation catalyst, cis,cis- [(bpy){sub 2}(H{sub 2}O)Ru{sup III}ORu{sup III}(OH{sub 2})(bpy){sub 2}]{sup 4+} (bpy is 2,2-bipyridine). Two computational approaches were compared: simulations without the core-hole and by modeling of the core-hole within the Z+1 approximation. Good agreement between calculated and experimental XANES spectra is achieved without including the core-hole. Simulations with algorithms beyond the Z+1 approximation were only possible in a framework of the scalar relativistic treatment. Time-dependent DFT (TD-DFT) was used to compute the Ru L-edge spectrum for [Ru(NH{sub 3}){sub 6}]{sup 3+} model compound. Three different core-hole treatments were compared in a real-space full multiple scattering XANES modeling within the Green function formalism (implemented in the FEFF9.5 package) for the [Ru(Mebimpy)(bpm)(H{sub 2}O)]{sup 2+} complex. The latter approaches worked well in cases where spin-orbit treatment of relativistic effects is not required.

Alperovich, Igor; Moonshiram, Dooshaye; Soldatov, Alexander; Pushkar, Yulia (SFU-Russia); (Purdue)

2012-10-09T23:59:59.000Z

70

Density Functional Theory Study of Copper Oxide as Low-cost ...  

Science Conference Proceedings (OSTI)

Density Functional Theory Study of Copper Oxide as Low-cost Photovoltaic Material · Dye-sensitized Solar Cells with Anodized Aluminum Alloy-based Counter- ...

71

Modeling the Noble Metal/TiO2 (110) Interface with Hybrid DFT Functionals: A Periodic Electrostatic Embedded Cluster Model Study  

Science Conference Proceedings (OSTI)

The interaction of Aun and Ptn (n=2,3) clusters with the stoichiometric and partially reduced rutile TiO2 (110) surfaces has been investigated using periodic slab and periodic electrostatic embedded cluster models. Compared to Au clusters, Pt clusters interact strongly with both stoichiometric and reduced TiO2 (110) surfaces and are able to enhance the reducibility of the TiO2 (110) surface, i.e., reduce the oxygen vacancy formation energy. The focus of this study is the effect of Hartree–Fock exchange on the description of the strength of chemical bonds at the interface of Au/Pt clusters and the TiO2 (110) surface. Hartree–Fock exchange helps describing the changes in the electronic structures due to metal cluster adsorption as well as their effect on the reducibility of the TiO2 surface. Finally, the performance of periodic embedded cluster models has been assessed by calculating the Pt adsorption and oxygen vacancy formation energies. Cluster models, together with hybrid PBE0 functional, are able to efficiently compute reasonable electronic structures of the reduced TiO2 surface and predict charge localization at surface oxygen vacancies, in agreement with the experimental data, that significantly affect computed adsorption and reaction energies.

Ammal, Salai Cheettu; Heyden, Andreas

2010-10-26T23:59:59.000Z

72

A Density Functional Theory Study of Formaldehyde Adsorption on Ceria  

Science Conference Proceedings (OSTI)

Molecular adsorption of formaldehyde on the stoichiometric CeO2(111) and CeO2(110) surfaces was studied using periodic density functional theory. Two adsorption modes (strong chemisorbed and weak physisorbed) were identified on both surfaces. This is consistent with recent experimental observations. On the (111) surface, formaldehyde strongly chemisorbs with an adsorption energy of 0.86 eV to form a dioxymethylene-like structure, in which a surface O lifts from the surface to bind with the C of formaldehyde. A weak physisorbed state with adsorption energy of 0.28 eV was found with the O of formaldehyde interacting with a surface Ce. On the (110) surface, dioxymethyelene formation was also observed, with an adsorption energy of 1.31 eV. The weakly adsorbed state of formaldehyde on the (110) surface was energetically comparable to the weak adsorption state on the (111) surface, but adsorption occurred through a formaldehyde C and surface O interaction. Analysis of the local density of states and charge density differences after adsorption shows that strong covalent bonding occurs between the C of formaldehyde and surface O when dioxymethylene forms. Calculated vibrational frequencies also confirm dioxymethylene formation. Our results also show that as the coverage increases, the adsorption of formaldehyde on the (111) surface becomes weak, but is nearly unaffected on the (110) surface. This work was supported by a Laboratory Directed Research and Development (LDRD) project of the Pacific Northwest National Laboratory (PNNL). The computations were performed using the Molecular Science Computing Facility in the William R. Wiley Environmental Molecular Sciences Laboratory, which is a U.S. Department of Energy national scientific user facility located at PNNL in Richland, Washington. Computing time was made under a Computational Grand Challenge “Computational Catalysis”. Part of the computing time was also granted by the National Energy Research Scientific Computing Center (NERSC).

Mei, Donghai; Deskins, N. Aaron; Dupuis, Michel

2007-11-01T23:59:59.000Z

73

A new DFT method for atoms and molecules in Cartesian grid  

E-Print Network (OSTI)

Electronic structure calculation of atoms and molecules, in the past few decades has largely been dominated by density functional methods. This is primarily due to the fact that this can account for electron correlation effects in a rigorous, tractable manner keeping the computational cost at a manageable level. With recent advances in methodological development, algorithmic progress as well as computer technology, larger physical, chemical and biological systems are amenable to quantum mechanical calculations than ever before. Here we report the development of a new method for accurate reliable description of atoms, molecules within the Hohenberg-Kohn-Sham density functional theory (DFT). In a Cartesian grid, atom-centered localized basis set, electron density, molecular orbitals, two-body potentials are directly built on the grid. We employ a Fourier convolution method for classical Coulomb potentials by making an Ewald-type decomposition technique in terms of short- and long-range interactions. One-body ma...

Roy, Amlan K

2013-01-01T23:59:59.000Z

74

Density Functional Theory in Surface Chemistry and Catalysis  

SciTech Connect

Recent advances in the understanding of reactivity trends for chemistry at transition metal surfaces have enabled in silico design of heterogeneous catalysts in a few cases. Current status of the field is discussed with an emphasis on the role of coupling between theory and experiment and future challenges.

Norskov, Jens

2011-05-19T23:59:59.000Z

75

Magnetic and antimagnetic rotation in covariant density functional theory  

Science Conference Proceedings (OSTI)

Progress on microscopic and self-consistent description of the magnetic rotation and antimagnetic rotation phenomena in tilted axis cranking relativistic mean-field theory based on a point-coupling interaction are briefly reviewed. In particular, the microscopic pictures of the shears mechanism in {sup 60}Ni and the two shears-like mechanism in {sup 105}Cd are discussed.

Zhao, P. W.; Liang, H. Z.; Peng, J.; Ring, P.; Zhang, S. Q.; Meng, J. [State Key Lab Nucl. Phys. and Tech., School of Physics, Peking University, Beijing 100871 (China); Department of Physics, Beijing Normal University, Beijing 100875 (China); State Key Lab Nucl. Phys. and Tech., School of Physics, Peking University, Beijing 100871 (China) and Physik Department, Technische Universitat Muenchen, D-85747 Garching (Germany); State Key Lab Nucl. Phys. and Tech., School of Physics, Peking University, Beijing 100871 (China); State Key Lab Nucl. Phys. and Tech., School of Physics, Peking University, Beijing 100871 (China) and Department of Physics, University of Stellenbosch, Stellenbosch (South Africa)

2012-10-20T23:59:59.000Z

76

Ligand Discrimination in Myoglobin from Linear-Scaling DFT+U  

E-Print Network (OSTI)

Myoglobin modulates the binding of diatomic molecules to its heme group via hydrogen-bonding and steric interactions with neighboring residues, and is an important benchmark for computational studies of biomolecules. We have performed calculations on the heme binding site and a significant proportion of the protein environment (more than 1000 atoms) using linear-scaling density functional theory and the DFT+U method to correct for self-interaction errors associated with localized 3d states. We confirm both the hydrogen-bonding nature of the discrimination effect (3.6 kcal/mol) and assumptions that the relative strain energy stored in the protein is low (less than 1 kcal/mol). Our calculations significantly widen the scope for tackling problems in drug design and enzymology, especially in cases where electron localization, allostery or long-ranged polarization influence ligand binding and reaction.

Cole, Daniel J; Payne, Mike C

2013-01-01T23:59:59.000Z

77

Green function identities in Euclidean quantum field theory  

E-Print Network (OSTI)

Given a generic Lagrangian system of even and odd fields, we show that any infinitesimal transformation of its classical Lagrangian yields the identities which Euclidean Green functions of quantum fields satisfy.

G. Sardanashvily

2006-04-01T23:59:59.000Z

78

Fission of actinides and superheavy nuclei: covariant density functional theory perspective  

E-Print Network (OSTI)

The current status of the application of covariant density functional theory to the description of fission barriers in actinides and superheavy nuclei is reviewed. The achievements and open problems are discussed.

A. V. Afanasjev

2013-03-05T23:59:59.000Z

79

Covariant Density Functional Theory--highlights on recent progress and applications  

SciTech Connect

The density functional theory with a few number of parameters allows a very successful phenomenological description of ground state properties of nuclei all over the nuclear chart. The recent progress on the application of the covariant density functional theory (CDFT) for nuclear structure and astrophysics as well as its extensions by the group in Beijing is summarized. In particular, its application to magnetic moments is discussed in details.

Meng, J. [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Li, J.; Zhao, P. W.; Liang, H. Z. [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Yao, J. M. [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China)

2011-05-06T23:59:59.000Z

80

Smoothness of the Gap Function in the BCS-Bogoliubov Theory of Superconductivity  

E-Print Network (OSTI)

We deal with the gap equation in the BCS-Bogoliubov theory of superconductivity, where the gap function is a function of the temperature $T$ only. We show that the squared gap function is of class $C^2$ on the closed interval $[\\,0,\\,T_c\\,]$. Here, $T_c$ stands for the transition temperature. Furthermore, we show that the gap function is monotonically decreasing on $[0,\\,T_c]$ and obtain the behavior of the gap function at $T=T_c$. We mathematically point out some more properties of the gap function.

Shuji Watanabe

2010-06-07T23:59:59.000Z

Note: This page contains sample records for the topic "functional theory dft" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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81

Empirical Proton-Neutron Interactions and Nuclear Density Functional Theory: Global, Regional and Local Comparisons  

E-Print Network (OSTI)

Calculations of nuclear masses, using nuclear density functional theory, are presented for even-even nuclei spanning the nuclear chart. The resulting binding energy differences can be interpreted in terms of valence proton-neutron interactions. These are compared globally, regionally, and locally with empirical values. Overall, excellent agreement is obtained. Discrepancies highlight neglected degrees of freedom and can point to improved density functionals.

Stoitsov, M; Casten, R F; Nazarewicz, W; Satula, W

2006-01-01T23:59:59.000Z

82

Empirical Proton-Neutron Interactions and Nuclear Density Functional Theory: Global, Regional, and Local Comparisons  

Science Conference Proceedings (OSTI)

Calculations of nuclear masses, using nuclear density functional theory, are presented for even-even nuclei spanning the nuclear chart. The resulting binding energy differences can be interpreted in terms of valence proton-neutron interactions. These are compared globally, regionally, and locally with empirical values. Overall, excellent agreement is obtained. Discrepancies highlight neglected degrees of freedom and can point to improved density functionals.

Stoitsov, Mario [ORNL; Cakirli, R. B. [Yale University; Casten, R. F. [Yale University; Nazarewicz, Witold [ORNL; Satula, W. [Warsaw University

2007-01-01T23:59:59.000Z

83

Empirical Proton-Neutron Interactions and Nuclear Density Functional Theory: Global, Regional and Local Comparisons  

E-Print Network (OSTI)

Calculations of nuclear masses, using nuclear density functional theory, are presented for even-even nuclei spanning the nuclear chart. The resulting binding energy differences can be interpreted in terms of valence proton-neutron interactions. These are compared globally, regionally, and locally with empirical values. Overall, excellent agreement is obtained. Discrepancies highlight neglected degrees of freedom and can point to improved density functionals.

M. Stoitsov; R. B. Cakirli; R. F. Casten; W. Nazarewicz; W. Satula

2006-11-14T23:59:59.000Z

84

Particle production in field theories coupled to strong external sources. II: Generating functions  

E-Print Network (OSTI)

We discuss a method for computing the generating function for the multiplicity distribution in field theories with strong time dependent external sources. At leading order, the computation of the generating function reduces to finding a pair of solutions of the classical equations of motion, with non-standard temporal boundary conditions.

Francois Gelis; Raju Venugopalan

2006-05-23T23:59:59.000Z

85

Density and pair-density scaling for deriving the Euler equation in density-functional and pair-density-functional theory  

Science Conference Proceedings (OSTI)

A link between density and pair density functional theories is presented. Density and pair density scaling are used to derive the Euler equation in both theories. Density scaling provides a constructive way of obtaining approximations for the Pauli potential. The Pauli potential (energy) of the density functional theory is expressed as the difference of the scaled and original exchange-correlation potentials (energies).

Nagy, A. [Department of Theoretical Physics, University of Debrecen, H-4010 Debrecen (Hungary)

2011-09-15T23:59:59.000Z

86

Fission barriers in actinides in covariant density functional theory: the role of triaxiality  

E-Print Network (OSTI)

Relativistic mean field theory allowing for triaxial deformations is applied for a systematic study of fission barriers in the actinide region. Different pairing schemes are studied in details and it is shown that covariant density functional theory is able to describe fission barriers on a level of accuracy comparable with non-relativistic calculations, even with the best phenomenological macroscopic+microscopic approaches. Triaxiality in the region of the first saddle plays a crucial role in achieving that.

H. Abusara; A. V. Afanasjev; P. Ring

2010-10-09T23:59:59.000Z

87

Effective 3-Body Interaction for Mean-Field and Density-Functional Theory  

Science Conference Proceedings (OSTI)

Density functionals for nuclei usually include an effective 3-body interaction that depends on a fractional power of the density. Using insights from the many-body theory of the low-density two-component Fermi gas, we consider a new, nonlocal, form for the energy functional that is consistent with the Fock-space representation of interaction operators. In particular, there is a unique spatially nonlocal generalization of the contact form of the interaction that preserves the {rho}{sup 7/3} density dependence required by the many-body theory. We calculate the ground-state energies for particles in a harmonic trap by using the nonlocal induced 3-body interaction and compare them to numerically accurate Green's function Monte Carlo calculations. Using no free parameters, we find that a nonlocality in the space domain provides a better description of the weak-coupling regime than the local-density approximation.

Gezerlis, Alexandros [Department of Physics, University of Washington, Seattle, Washington 98195-1560 (United States); Bertsch, G. F. [Department of Physics, University of Washington, Seattle, Washington 98195-1560 (United States); Institute for Nuclear Theory, University of Washington, Seattle, Washington 98195-1560 (United States)

2010-11-19T23:59:59.000Z

88

Gradient formula for the beta-function of 2d quantum field theory  

E-Print Network (OSTI)

We give a non-perturbative proof of a gradient formula for beta functions of two-dimensional quantum field theories. The gradient formula has the form \\partial_{i}c = - (g_{ij}+\\Delta g_{ij} +b_{ij})\\beta^{j} where \\beta^{j} are the beta functions, c and g_{ij} are the Zamolodchikov c-function and metric, b_{ij} is an antisymmetric tensor introduced by H. Osborn and \\Delta g_{ij} is a certain metric correction. The formula is derived under the assumption of stress-energy conservation and certain conditions on the infrared behaviour the most significant of which is the condition that the large distance limit of the field theory does not exhibit spontaneously broken global conformal symmetry. Being specialized to non-linear sigma models this formula implies a one-to-one correspondence between renormalization group fixed points and critical points of c.

Friedan, Daniel

2009-01-01T23:59:59.000Z

89

The structure of Green functions in quantum field theory with a general state  

E-Print Network (OSTI)

In quantum field theory, the Green function is usually calculated as the expectation value of the time-ordered product of fields over the vacuum. In some cases, especially in degenerate systems, expectation values over general states are required. The corresponding Green functions are essentially more complex than in the vacuum, because they cannot be written in terms of standard Feynman diagrams. Here, a method is proposed to determine the structure of these Green functions and to derive nonperturbative equations for them. The main idea is to transform the cumulants describing correlations into interaction terms.

Christian Brouder

2007-10-30T23:59:59.000Z

90

Determining Relative f and d Orbital Contributions to M?Cl Covalency in MCl62– (M = Ti, Zr, Hf, U) and UOCl5 Using Cl K-Edge X-ray Absorption Spectroscopy and Time-Dependent Density Functional Theory  

SciTech Connect

Chlorine K-edge X-ray absorption spectroscopy (XAS) and ground-state and time-dependent hybrid density functional theory (DFT) were used to probe electronic structure for O{sub h}-MCl{sub 6}{sup 2-}(M = Ti, Zr, Hf, U) and C{sub 4v}-UOCl{sub 5}{sup -}, and to determine the relative contributions of valence 3d, 4d, 5d, 6d, and 5f orbitals in M-Cl bonding. Spectral interpretations were guided by time-dependent DFT calculated transition energies and oscillator strengths, which agree well with the experimental XAS spectra. The data provide new spectroscopic evidence for the involvement of both 5f and 6d orbitals in actinide-ligand bonding in UCl{sub 6}{sup 2-}. For the MCl{sub 6}{sup 2-}, where transitions into d orbitals of t{sub 2g} symmetry are spectroscopically resolved for all four complexes, the experimentally determined Cl 3p character per M-Cl bond increases from 8.3(4)% (TiCl{sub 6}{sup 2-}) to 10.3(5)% (ZrCl{sub 6}{sup 2-}), 12(1)% (HfCl{sub 6}{sup 2-}), and 26 18(1)% (UCl{sub 6}{sup 2-}). Chlorine K-edge XAS spectra of UOCl{sub 5}{sup -} provide additional insights into the transition assignments by 27 lowering the symmetry to C{sub 4v}, where five pre-edge transitions into both 5f and 6d orbitals are observed. For UCl{sub 6}{sup 2-}, the XAS data 28 suggest that orbital mixing associated with the U 5f orbitals is considerably lower than that of the U 6d orbitals. For both UCl{sub 6}{sup 2-}29 and UOCl{sub 5}{sup -}, the ground-state DFT calculations predict a larger 5f contribution to bonding than is determined experimentally. 30 These findings are discussed in the context of conventional theories of covalent bonding for d- and f-block metal complexes.

Minasian, Stefan G.; Keith, Jason M.; Batista, Enrique R.; Boland, Kevin S.; Clark, David L.; Conradson, Steven D.; Kozimor, Stosh A.; Martin, Richard L.; Schwarz, Daniel E.; Shuh, David K.; Wagner, Gregory L.; Wilkerson, Marianne P.; Wolfsberg, Laura E.; Yang, Ping

2012-03-09T23:59:59.000Z

91

Study of Possible Ultraviolet Zero of the Beta Function in Gauge Theories with Many Fermions  

E-Print Network (OSTI)

We study the possibility of an ultraviolet (UV) zero in the $n$-loop beta function of U(1) and non-Abelian gauge theories with $N_f$ fermions for large $N_f$. The effect of scheme transformations on the coefficients of different powers of $N_f$ in the $n$-loop term in the beta function is calculated. A general scheme-independent criterion is given for determining whether or not the $n$-loop beta function has a UV zero for large $N_f$. We compare the results with exact integral representations of the leading terms in the beta functions for the respective Abelian and non-Abelian theories in the limit $N_f \\to \\infty$ limit with $N_f \\alpha$ finite. As part of this study, new analytic and numerical results are presented for certain coefficients, denoted $b_{n,n-1}$, that control the large-$N_f$ behavior at $n$-loop order in the beta function. We also investigate various test functions incorporating a power-law and essential UV zero in the beta function and determine their manifestations in series expansions in powers of coupling and in powers of $1/N_f$.

Robert Shrock

2013-11-20T23:59:59.000Z

92

Adaptive DFT-based interferometer fringe tracking  

Science Conference Proceedings (OSTI)

An automatic interferometer fringe tracking system has been developed, implemented, and tested at the Infrared Optical Telescope Array (IOTA) Observatory at Mount Hopkins, Arizona. The system can minimize the optical path differences (OPDs) for all three ... Keywords: DFT, IOTA, fringe tracking, interferometry, real time

Edward Wilson; Ettore Pedretti; Jesse Bregman; Robert W. Mah; Wesley A. Traub

2005-01-01T23:59:59.000Z

93

Steam Reforming on Transition-metal Carbides from Density-functional Theory  

Science Conference Proceedings (OSTI)

A screening study of the steam reforming reaction on clean and oxygen covered early transition-metal carbides surfaces is performed by means of density-functional theory calculations. It is found that carbides provide a wide spectrum of reactivities, from too reactive via suitable to too inert. Several molybdenum-based systems are identified as possible steam reforming catalysts. The findings suggest that carbides provide a playground for reactivity tuning, comparable to the one for pure metals.

Vojvodic, Aleksandra

2012-05-11T23:59:59.000Z

94

Spectral functions for composite fields and viscosity in hot scalar field theory  

E-Print Network (OSTI)

We derive a spectral representation for the two-point Green function for arbitrary composite field operators in Thermo Field Dynamics (TFD). A simple way for calculating the spectral density within TFD is pointed out and compared with known results from the imaginary time formalism. The method is applied to hot $\\phi^4$ theory. We give a compact derivation of the one-loop contribution to the shear viscosity and show that it is dominated by low-momentum plasmons.

Enke Wang; Xiaofei Zhang; Ulrich Heinz

1995-09-19T23:59:59.000Z

95

The Gluon Green's function in N=4 supersymmetric Yang-Mills theory.  

E-Print Network (OSTI)

energy limit of scattering amplitudes in the N = 4 supersymmetric Yang– Mills theory is studied by solving the corresponding BFKL equation in the next– to–leading approximation. The gluon Green’s function is analysed using a newly proposed method suitable... (~ka) ??(~kb) f ( ~ka, ~kb,Y ? ln s s0 ) , (1) where s0 = |~ka||~kb| is the Regge scale. The energy dependence is determined by the universal process–independent gluon Green’s function f . The impact factors, ?,??, depend on the process under study...

Andersen, Jeppe R; Sabio Vera, Agustin

96

An application of Green-function methods to gravitational radiation theory  

E-Print Network (OSTI)

Previous work in the literature has studied gravitational radiation in black-hole collisions at the speed of light. In particular, it had been proved that the perturbative field equations may all be reduced to equations in only two independent variables, by virtue of a conformal symmetry at each order in perturbation theory. The Green function for the perturbative field equations is here analyzed by studying the corresponding second-order hyperbolic operator with variable coefficients, instead of using the reduction method from the retarded flat-space Green function in four dimensions. After reduction to canonical form of this hyperbolic operator, the integral representation of the solution in terms of the Riemann function is obtained. The Riemann function solves a characteristic initial-value problem for which analytic formulae leading to the numerical solution are derived.

Giampiero Esposito

2005-04-27T23:59:59.000Z

97

Density Functional Theory and Molecular Dynamics Studies on Energetics and Kinetics for Electro-Active Polymers: PVDF and P(VDF-TrFE)  

E-Print Network (OSTI)

We use first principles methods to study static and dynamical mechanical properties of the ferroelectric polymer Poly(vinylidene fluoride) (PVDF) and its copolymer with trifluoro ethylene (TrFE). We use density functional theory [within the generalized gradient approximation (DFT-GGA)] to calculate structures and energetics for various crystalline phases for PVDF and P(VDF-TrFE). We find that the lowest energy phase for PVDF is a non-polar crystal with a combination of trans (T) and gauche (G) bonds; in the case of the copolymer the role of the extra (bulkier) F atoms is to stabilize T bonds. This leads to the higher crystallinity and piezoelectricity observed experimentally. Using the MSXX first principles-based force field (FF) with molecular dynamics (MD), we find that the energy barrier necessary to nucleate a kink (gauche pairs separated by trans bonds) in an all-T crystal is much lower (14.9 kcal/mol) in P(VDF-TrFE) copolymer than in PVDF (24.8 kcal/mol). This correlates with the observation that the polar phase of the copolymer exhibits a solid-solid a transition to a non-polar phase under heating while PVDF directly melts. We also studied the mobility of an interface between a polar and non-polar phases under uniaxial stress; we find a lower threshold stress and a higher mobility in the copolymer as compared with PVDF. Finally, considering plastic deformation under applied shear, we find that the chains for P(VDF-TrFE) have a very low resistance to sliding, particularly along the chain direction. The atomistic characterization of these "unit mechanisms" provides essential input to mesoscopic or macroscopic models of electro-active polymers.

H. B. Su; Alejandro Strachan; William A. Goddard III

2004-08-09T23:59:59.000Z

98

Sequential Circuit Testing: From DFT to SFT  

Science Conference Proceedings (OSTI)

Sequential circuit testing is an active research area due to its applicability, its practicality, and its complexity. This paper gives an overview of the sequential automatic test pattern generation approaches and the classical and more recent design-for-testability ... Keywords: logic testing, sequential circuit testing, DFT techniques, automatic test pattern generation, design-for-testability methods, synthesis-for-testability, SFT techniques, large sequential circuits, ATPG

R. M. Chou; K. K. Saluja

1997-01-01T23:59:59.000Z

99

Stress Isotherms of Porous Thin Materials: Theoretical Predictitions From a Nonlocal Density Functional Theory  

SciTech Connect

Recent beam bending (BB) experiments of microporous t31rns with very small pores have shown that the fluid confined in these pores exhibits monotonic compressive stresses as the relative pressure is varied from vacuum to saturation (relative vapor pressure, p/p. = 1). The variation of the stress near saturation is found to be linear in hz(p) and given by the saturated liquid density to within 20%. Capillary condensed fluids are traditionally described by the Laplace-Kelvin (LK) theory. LK theory correctly predicts the slope of the stress near saturation to be pl, but also predicts that the stress should be zero at saturation and tensile between saturation aud the capillary transition pressure. Hence LK theory does not capture the monotonic compressive stress observed in BB experiments. This report describes the results of density functional theory calculations for a simple fluid continued to a slit pore network. We show how the presence of even a small amount of polydispersity in pore size leads to both a monotonic compressive stress as well as the observed LK slope.

Frink, L.J.D.; van Swol, F.

1998-11-11T23:59:59.000Z

100

Green s functions in full-potential multiple-scattering theory  

Science Conference Proceedings (OSTI)

One-electron Green s functions play a central role in multiple-scattering theory (MST) based electronic- structure methods. Robust methods exist for calculating the Green s function for crystal potentials that are spherically symmetric about atomic centers. When applied to potentials of general shape, these same techniques result in pathologies in the small-r behavior of the electronic charge density because a portion of the Green s function can become singular at the origin for that case. We propose an algebraic method that eliminates the singular behavior by making use of the equivalence of two terms that involve poles in the inverse of the sine matrix. Our accurate calculations illustrate the limitations of previous methods for treating this problem that rely on extrapolating the solutions near the origin.

Rusanu, Aurelian [ORNL; Stocks, George Malcolm [ORNL; Wang, Yang [Pittsburgh Supercomputing Center; Faulkner, John Sam [Florida Atlantic University

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "functional theory dft" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Connected Green function approach to ground state symmetry breaking in $?^4_{1+1}$-theory  

E-Print Network (OSTI)

Using the cluster expansions for n-point Green functions we derive a closed set of dynamical equations of motion for connected equal-time Green functions by neglecting all connected functions higher than $4^{th}$ order for the $\\lambda \\Phi^4$-theory in $1+1$ dimensions. We apply the equations to the investigation of spontaneous ground state symmetry breaking, i.e. to the evaluation of the effective potential at temperature $T=0$. Within our momentum space discretization we obtain a second order phase transition (in agreement with the Simon-Griffith theorem) and a critical coupling of $\\lambda_{crit}/4m^2=2.446$ as compared to a first order phase transition and $\\lambda_{crit}/4m^2=2.568$ from the Gaussian effective potential approach.

J. M. Haeuser; W. Cassing; A. Peter; M. H. Thoma

1994-08-23T23:59:59.000Z

102

Geometrical Characterization of Adenine And Guanine on Cu(110) By NEXAFS, XPS, And DFT Calculation  

Science Conference Proceedings (OSTI)

Adsorption of purine DNA bases (guanine and adenine) on Cu(1 1 0) was studied by X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine-structure spectroscopy (NEXAFS), and density-functional theory (DFT) calculation. At coverages near 0.2 monolayers, Angular-resolved NEXAFS analysis revealed that adenine adsorbates lie almost flat and that guanine adsorbates are tilted up on the surface with the purine ring parallel to the atom rows of Cu(1 1 0). Referring to the previous studies on pyrimidine DNA bases [M. Furukawa, H. Fujisawa, S. Katano, H. Ogasawara, Y. Kim, T. Komeda, A. Nilsson, M. Kawai, Surf. Sci. 532-535 (2003) 261], the isomerization of DNA bases on Cu(1 1 0) was found to play an important role in the adsorption geometry. Guanine, thymine and cytosine adsorption have an amine-type nitrogen next to a carbonyl group, which is dehydrogenated into imine nitrogen on Cu(1 1 0). These bases are bonded by the inherent portion of - NH-CO - altered by conversion into enolic form and dehydrogenation. Adenine contains no CO group and is bonded to Cu(1 1 0) by participation of the inherent amine parts, resulting in nearly flatly-lying position.

Furukawa, M.; Yamada, T.; /Wako, RIKEN; Katano, S.; /tohoku U.; Kawai, M.; /Wako, RIKEN /Tokyo U.; Ogasawara, H.; /SLAC, SSRL; Nilsson, A.; /SLAC, SSRL /Stockholm U.

2009-04-30T23:59:59.000Z

103

Construction of the free energy landscape by the density functional theory  

E-Print Network (OSTI)

On the basis of the density functional theory, we give a clear definition of the free energy landscape. To show the usefulness of the definition, we construct the free energy landscape for rearrangement of atoms in an FCC crystal of hard spheres. In this description, the cooperatively rearranging region (CRR) is clealy related to the hard spheres involved in the saddle between two adjacent basins. A new concept of the simultaneously rearranging region (SRR) emerges naturally as spheres defined by the difference between two adjacent basins. We show that the SRR and the CRR can be determined explicitly from the free energy landscape. 1 1

Takashi Yoshidome; Akira Yoshimori; Takashi Odagaki

2005-01-01T23:59:59.000Z

104

Oxidation of stepped Pt(111) studied by x-ray photoelectron spectroscopy and density functional theory  

SciTech Connect

In this comparative density functional theory and x-ray photoelectron spectroscopy study on the interaction of oxygen with stepped Pt(111) surfaces, we show that both the initial adsorption and oxidation occur at the steps rather than terraces. An equivalent behavior was observed for the oxide formation at higher chemical potentials, where, after the formation of a one-dimensional PtO{sub 2}-type oxide at the steps, similar oxide chains form on the (111) terraces, indicating the initial stages of bulk oxide formation.

Bandlow, Jochen; Kaghazchi, Payam; Jacob, Timo [Institut fuer Elektrochemie, Universitaet Ulm, Albert-Einstein-Allee 47, D-89069 Ulm (Germany); Papp, C.; Traenkenschuh, B.; Streber, R.; Lorenz, M. P. A.; Fuhrmann, T.; Steinrueck, H.-P. [Lehrstuhl fuer Physikalische Chemie II, Universitaet Erlangen-Nuernberg, Egerlandstr. 3, D-91058 Erlangen (Germany); Denecke, R. [Wilhelm-Ostwald-Institut fuer Physikalische und Theoretische Chemie, Universitaet Leipzig, Linnestr. 2, D-04103 Leipzig (Germany)

2011-05-01T23:59:59.000Z

105

Equilibrium gas-liquid-solid contact angle from density-functional theory  

E-Print Network (OSTI)

We investigate the equilibrium of a fluid in contact with a solid boundary through a density-functional theory. Depending on the conditions, the fluid can be in one phase, gas or liquid, or two phases, while the wall induces an external field acting on the fluid particles. We first examine the case of a liquid film in contact with the wall. We construct bifurcation diagrams for the film thickness as a function of the chemical potential. At a specific value of the chemical potential, two equally stable films, a thin one and a thick one, can coexist. As saturation is approached, the thickness of the thick film tends to infinity. This allows the construction of a liquid-gas interface that forms a well defined contact angle with the wall.

Pereira, Antonio

2010-01-01T23:59:59.000Z

106

Troubleshooting time-dependent density-functional theory for photochemical applications: Oxirane  

Science Conference Proceedings (OSTI)

The development of analytic-gradient methodology for excited states within conventional time-dependent density-functional theory (TDDFT) would seem to offer a relatively inexpensive alternative to better established quantum-chemical approaches for the modeling of photochemical reactions. However, even though TDDFT is formally exact, practical calculations involve the use of approximate functional, in particular the TDDFT adiabatic approximation, the use of which in photochemical applications must be further validated. Here, we investigate the prototypical case of the symmetric CC ring opening of oxirane. We demonstrate by direct comparison with the results of high-quality quantum Monte Carlo calculations that, far from being an approximation on TDDFT, the Tamm-Dancoff approximation is a practical necessity for avoiding triplet instabilities and singlet near instabilities, thus helping maintain energetically reasonable excited-state potential energy surfaces during bond breaking. Other difficulties one would encounter in modeling oxirane photodynamics are pointed out.

Cordova, Felipe; Doriol, L. Joubert; Ipatov, Andrei; Casida, Mark E.; Filippi, Claudia; Vela, Alberto [Laboratoire de Chimie Theorique, Departement de Chimie Molecularie (DCM, UMR CNRS/UJF 5250), Institut de Chimie Moleculaire de Grenoble (ICMG, FR2607), Universite Joseph Fourier - Grenoble I, 301 rue de la Chimie, BP 53, F-38041 Grenoble Cedex 9 (France); Instituut-Lorentz for Theoretical Physics, Universiteit Leiden, Niels Bohrweg 2, Leiden NL-2333 CA Netherlands (Netherlands); Departamento de Quimica, Cinvestav, Avenida Instituto Politecnico Nacional 2508, A.P. 14-740, Mexico D.F. 07000 (Mexico)

2007-10-28T23:59:59.000Z

107

Steam reforming on transition-metal carbides from density-functional theory  

E-Print Network (OSTI)

A screening study of the steam reforming reaction (CH_4 + H_2O -> CO + 3H_2) on early transition-metal carbides (TMC's) is performed by means of density-functional theory calculations. The set of considered surfaces includes the alpha-Mo_2C(100) surfaces, the low-index (111) and (100) surfaces of TiC, VC, and delta-MoC, and the oxygenated alpha-Mo_2C(100) and TMC(111) surfaces. It is found that carbides provide a wide spectrum of reactivities towards the steam reforming reaction, from too reactive via suitable to too inert. The reactivity is discussed in terms of the electronic structure of the clean surfaces. Two surfaces, the delta-MoC(100) and the oxygen passivated alpha-Mo_2C(100) surfaces, are identified as promising steam reforming catalysts. These findings suggest that carbides provide a playground for reactivity tuning, comparable to the one for pure metals.

Vojvodic, Aleksandra

2009-01-01T23:59:59.000Z

108

Adaptive local basis set for Kohn-Sham density functional theory in a discontinuous Galerkin framework I: Total energy calculation  

E-Print Network (OSTI)

Kohn-Sham density functional theory is one of the most widely used electronic structure theories. Uniform discretization of the Kohn-Sham Hamiltonian generally results in a large number of basis functions per atom in order to resolve the rapid oscillations of the Kohn-Sham orbitals around the nuclei. Previous attempts to reduce the number of basis functions per atom include the usage of atomic orbitals and similar objects, but the atomic orbitals generally require fine tuning in order to reach the chemical accuracy. We present a novel discretization scheme that adaptively and systematically builds the rapid oscillations of the Kohn-Sham orbitals around the nuclei as well as environmental effects into the basis functions. The resulting basis functions are localized in the real space, and are discontinuous in the global domain. The continuous Kohn-Sham orbitals and the electron density are evaluated from the discontinuous basis functions using the discontinuous Galerkin (DG) framework. Our method is implemented...

Lin, Lin; Ying, Lexing; E, Weinan

2011-01-01T23:59:59.000Z

109

Structure and energetics of solvated ferrous and ferric ions: Car-Parrinello molecular dynamics in the DFT+U formalism  

E-Print Network (OSTI)

We implemented a rotationally-invariant Hubbard U extension to density-functional theory in the Car-Parrinello molecular dynamics framework, with the goal of bringing the accuracy of the DFT+U approach to finite-temperature simulations, especially for liquids or solids containing transition-metal ions. First, we studied the effects on the Hubbard U on the static equilibrium structure of the hexa-aqua ferrous and ferric ions, and the inner-sphere reorganization energy for the electron-transfer reaction between aqueous ferrous and ferric ions. It is found that the reorganization energy is increased, mostly as a result of the Fe-O distance elongation in the hexa-aqua ferrous ion. Second, we performed a first-principles molecular dynamics study of the solvation structure of the two aqueous ferrous and ferric ions. The Hubbard term is found to change the Fe-O radial distribution function for the ferrous ion, while having a negligible effect on the aqueous ferric ion. Moreover, the frequencies of vibrations between Fe and oxygen atoms in the first-solvation shell are shown to be unaffected by the Hubbard corrections for both ferrous and ferric ions.

P. H. -L. Sit; Matteo Cococcioni; Nicola Marzari

2007-01-12T23:59:59.000Z

110

Functioning, Item Response TheoryImplicit Theories and Beta Change in Longitudinal Evaluations of Training Effectiveness: An Investigation Using Item Response Theory  

E-Print Network (OSTI)

Golembiewski, Billingsly, and Yeager (1976) conceptualized three distinct types of change that might result from development interventions, called alpha, beta, and gamma change. Recent research has found that beta and gamma change do occur as hypothesized, but the phenomena are somewhat infrequent and the precise conditions under which they occur have not been established. This study used confirmatory factor analysis and item response theory to identify gamma and beta change on a multidimensional, multisource managerial performance appraisal instrument and to examine relations among the change types, training program content, and raters' implicit theories of performance. Results suggested that coverage in training was a necessary but not sufficient condition for beta and gamma change to occur. Further, although gamma change was detected only in the trainee group, beta change was detected in self-ratings from trainees and in ratings collected from their superiors. Because trainees ' superiors were involved in post-training follow-up, this finding was interpreted as a possible diffusion of treatments effect (Campbell & Stanley, 1963). Contrary to expectations, there were no interpretable relations between raters' implicit theories of performance and either of the change types. Perhaps relatedly, more implicit theory change was detected among individuals providing observer ratings than in the trainees

S. Bartholomew Craig; Robert J. Harvey (chair; Kevin D. Carlson; John Donovan; Roseanne J. Foti; Neil M. A. Hauenstein; S. Bartholomew Craig

2002-01-01T23:59:59.000Z

111

Study of Hydrogen Bonding in Small Water Clusters with Density Functional Theory Calculations  

DOE Green Energy (OSTI)

The unique characteristics of hydrogen bonding have left our understanding of liquid water far from complete in terms of its structure and properties. In order to better describe the hydrogen bond in water, we seek to understand the electronic states which show sensitivity to hydrogen bonding. We investigate the structure of unoccupied valence states by performing X-ray Absorption calculations on water clusters using Density Functional Theory. For each water cluster, studying how valence electronic structure is perturbed by changes in the local hydrogen bonding environment facilitates our description of the hydrogen bond. Also in this framework, we move toward a depiction of local structures in liquid water by comparison to experimental X-ray absorption spectra. We find consistent localization along internal bonds in the electronic structures of pre- and post-edge states for single-donor species. In addition, we propose a molecular orbital bonding-antibonding picture to explain this directional localization from dimer calculations, and show that the pre- and post-edge spectral regions have a resulting relationship.

Wendlandt, Johanna; /Wisconsin U., Madison /SLAC, SSRL

2005-12-15T23:59:59.000Z

112

Traffic scheduling mechanism based on graph theory for Power Saving mode of IEEE 802.11 distributed coordinator function  

Science Conference Proceedings (OSTI)

In IEEE 802.11 Power Saving (PS) mode specified for Independent Basic Service Set (IBSS), mobile stations announce their pending data packets within Announcement Traffic Indication Message (ATIM) window immediately after the reception ... Keywords: IEEE 80211, MAC protocol, ad hoc networks, distributed coordinator, energy efficiency, graph theory, medium access control, power saving, power-efficient, time synchronisation function, traffic scheduling

M. H. Ye; C. T. Lau; A. B. Premkumar

2009-03-01T23:59:59.000Z

113

Density Functional Theory Study of Methanol Decomposition on the CeO2(110) Surface  

Science Conference Proceedings (OSTI)

Methanol decomposition on the stoichiometric CeO2(110) surface has been investigated using density functional theory slab calculations. Three possible initial steps to decompose methanol by breaking one of three bonds (O?H, C?O and C?H) of methanol were examined. The relative order of thermodynamic stability for the three possible bond scission steps is: C?H > O?H > C?O. We further isolated transition state and determined activation energy for each bond-breaking mode using the nudged elastic method. The activation barrier for the most favorable dissociation mode, the O?H bond scission, is 0.3 eV on the (110) surface. An even lower activation barrier ( C?O > C?H. Our results are consistent with the previous experimental observation that methoxy is the dominant surface species after a stoichiometric CeO2 surface was exposed to methanol. The experimentally observed methanol chemistry was determined by the kinetics of initial dissociation steps rather than the thermodynamic stability of product states. Surface coverage of methanol was found to affect the relative stability between molecular and dissociative adsorption modes. Dissociative adsorption modes are preferred thermodynamically for methanol coverage up to 0.5 ML but only molecular adsorption was stable at full monolayer coverage. This work was supported by a Laboratory Directed Research and Development (LDRD) project of the Pacific Northwest National Laboratory (PNNL). The computations were performed using the Molecular Science Computing Facility in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL), which is a U.S. Department of Energy national scientific user facility located at PNNL in Richland, Washington. Computing time was made under a Computational Grand Challenge “Computational Catalysis”. Part of the computing time was also granted by the National Energy Research Scientific Computing Center (NERSC).

Mei, Donghai; Deskins, N. Aaron; Dupuis, Michel; Ge, Qingfeng

2008-03-20T23:59:59.000Z

114

Spontaneous Fission Modes and Lifetimes of Superheavy Elements in the Nuclear Density Functional Theory  

Science Conference Proceedings (OSTI)

Background: The reactions with the neutron-rich 48Ca beam and actinide targets resulted in the detection of new superheavy (SH) nuclides with Z=104 118. The unambiguous identification of the new isotopes, however, still poses a problem because their -decay chains terminate by spontaneous fission (SF) before reaching the known region of the nuclear chart. The understanding of the competition between -decay and SF channels in SH nuclei is, therefore, of crucial importance for our ability to map the SH region and to assess its extent. Purpose: We perform self-consistent calculations of the competing decay modes of even-even SH isotopes with 108 Z 126 and 148 N 188. Methods: We use the state-of-the-art computational framework based on self-consistent symmetry-unrestricted nuclear density functional theory capable of describing the competition between nuclear attraction and electrostatic repulsion. We apply the SkM* Skyrme energy density functional. The collective mass tensor of the fissioning superfluid nucleus is computed by means of the cranking approximation to the adiabatic time-dependent Hartree-Fock-Bogoliubov (HFB) approach. This paper constitutes a systematic self-consistent study of spontaneous fission in the SH region, carried out at a full HFB level, that simultaneously takes into account both triaxiality and reflection asymmetry. Results: Breaking axial symmetry and parity turns out to be crucial for a realistic estimate of collective action; it results in lowering SF lifetimes by more than 7 orders of magnitude in some cases. We predict two competing SF modes: reflection symmetric modes and reflection asymmetric modes. Conclusions: The shortest-lived SH isotopes decay by SF; they are expected to lie in a narrow corridor formed by 280Hs, 284Fl, and 118284Uuo that separates the regions of SH nuclei synthesized in cold-fusion and hot-fusion reactions. The region of long-lived SH nuclei is expected to be centered on 294Ds with a total half-life of 1.5 days. Our survey provides a solid benchmark for the future improvements of self-consistent SF calculations in the region of SH nuclei.

Staszczak, A, [UTK/ORNL/Inst. Physics, Maria Curie-Sklodowska University, Poland; Baran, A. [UTK/ORNL/Inst. Physics, Maria Curie-Sklodowska University, Poland; Nazarewicz, Witold [UTK/ORNL/University of Warsaw

2013-01-01T23:59:59.000Z

115

Study of Scheme Transformations to Remove Higher-Loop Terms in the $?$ Function of a Gauge Theory  

E-Print Network (OSTI)

Since three-loop and higher-loop terms in the $\\beta$ function of a gauge theory are scheme-dependent, one can, at least for sufficiently small coupling, carry out a scheme transformation that removes these terms. A basic question concerns the extent to which this can be done at an infrared fixed point of an asymptotically free gauge theory. This is important for quantitative analyses of the scheme dependence of such a fixed point. Here we study a scheme transformation $S_{R,m}$ with $m \\ge 2$ that is constructed so as to remove the terms in the beta function at loop order $\\ell=3$ to $\\ell=m+1$, inclusive. Starting from an arbitrary initial scheme, we present general expressions for the coefficients of terms of loop order $\\ell$ in the beta function in the transformed scheme from $\\ell=m+2$ up to $\\ell=8$. Extending a previous study of $S_{R,2}$, we investigate the range of applicability of the $S_{R,3}$ scheme transformation in an asymptotically free SU($N_c$) gauge theory with an infrared zero in $\\beta$ depending on the number, $N_f$, of fermions in the theory. We show that this $S_{R,3}$ scheme transformation can only be applied self-consistently in a restricted range of $N_f$ with a correspondingly small value of infrared fixed-point coupling. We also study the effect of higher-loop terms on the beta function of a U(1) gauge theory.

Robert Shrock

2013-05-28T23:59:59.000Z

116

Comparison of Small Polaron Migration and Phase Separation in Olivine LiMnPO? and LiFePO? using Hybrid Density Functional Theory  

E-Print Network (OSTI)

Using hybrid density functional theory based on the Heyd-Scuseria-Ernzerhof (HSE06) functional, we compared polaron migration and phase separation in olivine LiMnPO? to LiFePO?. The barriers for free hole and electron ...

Ong, Shyue Ping

117

Building A Universal Nuclear Energy Density Functional (UNEDF)  

Science Conference Proceedings (OSTI)

During the period of Dec. 1 2006 â?? 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.

Carlson, Joe, Los Alamos National Laboratory, Los Alamos, NM; Furnstahl, Dick, Ohio State University, Columbus, OH; Horoi, Mihai, Central Michigan University, Mount Pleasant, MI; Lusk, Rusty, Argonne National Laboratory, Argonne, IL; Nazarewicz, Witek, University of Tennessee, Knoxville, TN; Ng, Esmond, Berkeley National Laboratory, Berkeley, CA; Thompson, Ian, Lawrence Livermore National Laboratory, Livermore, CA; Vary, James, Iowa State University, Ames, Iowa

2012-09-30T23:59:59.000Z

118

Density Functional Theory Study of Surface Carbonate Formation on BaO(001)  

Science Conference Proceedings (OSTI)

Periodic density functional theory calculations have been used to study the formation and stability of surface carbonate on BaO(001) upon CO2 exposures. CO2 adsorbs at Lewis basic Os site forming anionic surface carbonate ( ) species until one monolayer coverage (1ML). Certain amount of electrons has been transferred from the surface to CO2 after CO2 adsorption. The adsorption energy of CO2 decreases with the increasing coverage as a combinative result of the less electrons accepted by each adsorbed CO2 and the lateral repulsive interactions. At ?CO2 0.75 ML, dramatic surface reconstruction had been found for the parallel pattern of surface carbonates that initially arranged on BaO(001). Due to strong lateral repulsion between the surface carbonates, the surface reconstruction actually pulls the surface Ba atom out of the surface plane, suggesting a possible onset of phase transition from surface carbonate overlayer to crystalline bulk-like barium carbonate. Surface free energy calculations have been performed to study the stability of surface carbonate at different temperature and pressure conditions. Our calculations indicate that surface carbonates decompose at 850 K at low coverage. For the fully covered carbonate overlayer, surface carbonate will become unstable at about 600 K. This is in good agreement with previous experimental observations. Finally, the effect of surface hydroxyl on the stability of surface carbonate is investigated. At low hydroxyl coverage, the neighboring hydroxyl stabilizes surface carbonate. On the fully hydroxylated BaO surface, the chelating bicarbonate instead of surface carbonate is formed upon CO2 adsorption. This work, performed in the Institute for Interfacial Catalysis at Pacific Northwest National Laboratory (PNNL), was partially supported by a PNNL Laboratory Directed Research and Development (LDRD) project. Computing time was granted by the National Energy Research Scientific Computing Center (NERSC) under project No. m752, and also by the scientific user project (st30469) using the Molecular Science Computing Facility in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL). The EMSL is a U.S. DOE national scientific user facility located at PNNL, and supported by the DOE’s Office of Biological and Environmental Research.

Mei, Donghai

2010-02-04T23:59:59.000Z

119

Development of Novel Density Functionals for Thermochemical Kinetics  

E-Print Network (OSTI)

A new density functional theory (DFT) exchange-correlation functional for the exploration of reaction mechanisms is proposed. This new functional, denoted BMK (Boese-Martin for Kinetics), has an accuracy in the 2 kcal/mol range for transition state barriers but, unlike previous attempts at such a functional, this improved accuracy does not come at the expense of equilibrium properties. This makes it a general-purpose functional whose domain of applicability has been extended to transition states, rather than a specialized functional for kinetics. The improvement in BMK rests on the inclusion of the kinetic energy density together with a large value of the exact exchange mixing coefficient. For this functional, the kinetic energy density appears to correct `back' the excess exact exchange mixing for ground-state properties, possibly simulating variable exchange.

Boese, A D; Martin, Jan M. L.

2004-01-01T23:59:59.000Z

120

Free-energy functionals of the electrostatic potential for Poisson-Boltzmann theory  

E-Print Network (OSTI)

In simulating charged systems, it is often useful to treat some ionic components of the system at the mean-field level and solve the Poisson-Boltzmann (PB) equation to get their respective density profiles. The numerically intensive task of solving the PB equation at each step of the simulation can be bypassed using variational methods that treat the electrostatic potential as a dynamic variable. But such approaches require the access to a true free-energy functional; a functional that not only provides the correct solution of the PB equation upon extremization, it also evaluates to the true free energy of the system at its minimum. Moreover, the numerical efficiency of such procedures is further enhanced if the free-energy functional is local and is expressed in terms of the electrostatic potential. Existing PB functionals of the electrostatic potential, while possessing the local structure, are not free-energy functionals. We present a variational formulation with a local free-energy functional of the potential. In addition, we also construct a nonlocal free-energy functional of the electrostatic potential. These functionals are suited for employment in simulation schemes based on the ideas of dynamical optimization.

Vikram Jadhao; Francisco J. Solis; Monica Olvera de la Cruz

2013-09-26T23:59:59.000Z

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121

Quantum field theory in the presence of a medium: Green's function expansions  

SciTech Connect

Starting from a Lagrangian and using functional-integration techniques, series expansions of Green's function of a real scalar field and electromagnetic field, in the presence of a medium, are obtained. The parameter of expansion in these series is the susceptibility function of the medium. Relativistic and nonrelativistic Langevin-type equations are derived. Series expansions for Lifshitz energy in finite temperature and for an arbitrary matter distribution are derived. Covariant formulations for both scalar and electromagnetic fields are introduced. Two illustrative examples are given.

Kheirandish, Fardin [Department of Physics, Islamic Azad University, Shahreza-Branch, Shahreza (Iran, Islamic Republic of); Salimi, Shahriar [Department of Physics, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)

2011-12-15T23:59:59.000Z

122

Core and Valence Excitations in Resonant X-ray Spectroscopy using Restricted Excitation Window Time-dependent Density Functional Theory  

Science Conference Proceedings (OSTI)

We report simulations of X-ray absorption near edge structure (XANES), resonant inelastic X-ray scattering (RIXS) and 1D stimulated X-ray Raman spectroscopy (SXRS) signals of cysteine at the oxygen, nitrogen and sulfur K and L2,3 edges. The simulated XANES signals from the restricted window time-dependent density functional theory (REW-TDDFT) and the static exchange (STEX) method are compared with experiments, showing that REW-TDDFT is more accurate and computationally less expensive than STEX. Simulated RIXS and 1D SXRS signals from REW-TDDFT give some insights on the correlation of different excitations in the molecule.

Zhang, Yu; Biggs, Jason D.; Healion, Daniel; Govind, Niranjan; Mukamel, Shaul

2012-11-21T23:59:59.000Z

123

Of energy and the economy : theory and evidence for their functional relationship  

E-Print Network (OSTI)

This paper offers a set of explicit functional relationships that link energy and the economy. Despite the reliance on energy permeating the whole economy, no such complete relationships had been presented before. How ...

Chang, Vincent H. (Vincent Hua-Cheng)

2007-01-01T23:59:59.000Z

124

Coulomb gauge Green functions and Gribov copies in SU(2) lattice gauge theory  

E-Print Network (OSTI)

We reconsider the lattice measurement of Green functions in Coulomb gauge, both in 2+1 and 3+1 dimensions, using an improved gauge fixing scheme. The influence of Gribov copies is examined and we find clear indications that Green functions are more strongly affected than previously assumed, in particular for low momenta. Qualitatively, our improved lattice results in the infra-red compare more favourably with recent continuum calculations in the Hamiltonian approach.

M. Quandt; G. Burgio; S. Chimchinda; H. Reinhardt

2007-10-02T23:59:59.000Z

125

Perspective: Advances and challenges in treating van der Waals dispersion forces in density functional theory  

E-Print Network (OSTI)

of the previous noble gas and group III atom. Fur- thermore, the dispersion energy, Edisp, is scaled according range dispersion interaction with the underlying exchange or XC functionals. A. Gas phase clustersPerspective: Advances and challenges in treating van der Waals dispersion forces in density

Alavi, Ali

126

The theory of social functions: challenges for computational social science and multi-agent learning  

Science Conference Proceedings (OSTI)

A basic claim of this paper is that the foundational theoretical problem of the social sciences - the possibility of unconscious, unplanned forms of cooperation and intelligence among intentional agents (the very hard issue of the 'invisible hand', of ... Keywords: Agents, Cognitive architecture, Emergence, Intention, Learning, Social functions, Social simulation

Cristiano Castelfranchi

2001-04-01T23:59:59.000Z

127

Prediction of [superscript 57] Fe Mossbauer Parameters by Density Functional Theory: A Benchmark Study  

E-Print Network (OSTI)

We report the performance of eight density functionals (B3LYP, BPW91, OLYP, O3LYP, M06, M06-2X, PBE, and SVWN5) in two Gaussian basis sets (Wachters and Partridge-1 on iron atoms; cc-pVDZ on the rest of atoms) for prediction ...

Bochevarov, Arteum D.

128

Theory and simulation of quantum photovoltaic devices based on the non-equilibrium Green's function formalism  

Science Conference Proceedings (OSTI)

This article reviews the application of the non-equilibrium Green's function formalism to the simulation of novel photovoltaic devices utilizing quantum confinement effects in low dimensional absorber structures. It covers well-known aspects of the fundamental ... Keywords: NEGF, Photovoltaics, Quantum dot, Quantum well

U. Aeberhard

2011-12-01T23:59:59.000Z

129

Solitons, Tau-functions and Hamiltonian Reduction for Non-Abelian Conformal Affine Toda Theories  

E-Print Network (OSTI)

We consider the Hamiltonian reduction of the two-loop Wess-Zumino-Novikov-Witten model (WZNW) based on an untwisted affine Kac-Moody algebra $\\cgh$. The resulting reduced models, called {\\em Generalized Non-Abelian Conformal Affine Toda (G-CAT)}, are conformally invariant and a wide class of them possesses soliton solutions; these models constitute non-abelian generalizations of the Conformal Affine Toda models. Their general solution is constructed by the Leznov-Saveliev method. Moreover, the dressing transformations leading to the solutions in the orbit of the vacuum are considered in detail, as well as the $\\tau$-functions, which are defined for any integrable highest weight representation of $\\cgh$, irrespectively of its particular realization. When the conformal symmetry is spontaneously broken, the G-CAT model becomes a generalized Affine Toda model, whose soliton solutions are constructed. Their masses are obtained exploring the spontaneous breakdown of the conformal symmetry, and their relation to the fundamental particle masses is discussed.

L. A. Ferreira; J. L. Miramontes; J. Sanchez Guillen

1994-12-15T23:59:59.000Z

130

On the Structure and Geometry of Biomolecular Binding Motifs (Hydrogen-Bonding, Stacking, X-H· · ·?): WFT and DFT Calculations  

DOE Green Energy (OSTI)

The strengths of noncovalent interactions are generally very sensitive to a number of geometric parameters. Among the most important of these parameters is the separation between the interacting moieties (in the case of an intermolecular interaction, this would be the intermolecular separation). Most works seeking to characterize the properties of intermolecular interactions are mainly concerned with binding energies obtained at the potential energy minimum (as determined at some particular level of theory). In this work, in order to extend our understanding of these types of noncovalent interactions, we investigate the distance dependence of several types of intermolecular interactions, these are hydrogen bonds, stacking interactions, dispersion interactions, and X-H· · ·? interactions. There are several methods that have traditionally been used to treat noncovalent interactions as well as many new methods that have emerged within the past three or four years. Here we obtain reference data using estimated CCSD(T) values at the complete basis set limit (using the CBS(T) method); potential energy curves are also produced using several other methods thought to be accurate for intermolecular interactions, these are MP2/ccpVTZ, MP2/aug-cc-pVDZ,MP2/6-31G*(0.25), SCS(MI)-MP2/cc-pVTZ, estimated MP2.5/CBS, DFT-SAPT/ aug-cc-pVTZ, DFT/M06-2X/6-311+G(2df,2p), and DFT-D/TPSS/6-311++G(3df,3pd). The basis set superposition error is systematically considered throughout the study. It is found that the MP2.5 and DFTSAPT methods, which are both quite computationally intensive, produce potential energy curves that are in very good agreement to those of the reference method. Among the MP2 techniques, which can be said to be of medium computational expense, the best results are obtained with MP2/cc-pVTZ and SCS(MI)-MP2/cc-pVTZ. DFT-D/TPSS/6-311++G(3df,3pd) is the DFT-based method that can be said to give the most well-balanced description of intermolecular interactions.

Riley, Kevin E.; Pitonak, Michal; Cerny, Jiri; Hobza, Pavel

2009-12-09T23:59:59.000Z

131

The Spacetime of Double Field Theory: Review, Remarks, and Outlook  

E-Print Network (OSTI)

We review double field theory (DFT) with emphasis on the doubled spacetime and its generalized coordinate transformations, which unify diffeomorphisms and b-field gauge transformations. We illustrate how the composition of generalized coordinate transformations fails to associate. Moreover, in dimensional reduction, the O(d,d) T-duality transformations of fields can be obtained as generalized diffeomorphisms. Restricted to a half-dimensional subspace, DFT includes `generalized geometry', but is more general in that local patches of the doubled space may be glued together with generalized coordinate transformations. Indeed, we show that for certain T-fold backgrounds with non-geometric fluxes, there are generalized coordinate transformations that induce, as gauge symmetries of DFT, the requisite O(d,d;Z) monodromy transformations. Finally we review recent results on the \\alpha' extension of DFT which, reduced to the half-dimensional subspace, yields intriguing modifications of the basic structures of generalized geometry.

Olaf Hohm; Dieter Lust; Barton Zwiebach

2013-09-11T23:59:59.000Z

132

Density Functional Theory Simulations Predict New Materials for Magnesium-Ion Batteries (Fact Sheet), NREL Highlights, Science  

SciTech Connect

Multivalence is identified in the light element, B, through structure morphology. Boron sheets exhibit highly versatile valence, and the layered boron materials may hold the promise of a high-energy-density magnesium-ion battery. Practically, boron is superior to previously known multivalence materials, especially transition metal compounds, which are heavy, expensive, and often not benign. Based on density functional theory simulations, researchers at the National Renewable Energy Laboratory (NREL) have predicted a series of stable magnesium borides, MgB{sub x}, with a broad range of stoichiometries, 2 < x < 16, by removing magnesium atoms from MgB{sub 2}. The layered boron structures are preserved through an in-plane topological transformation between the hexagonal lattice domains and the triangular domains. The process can be reversibly switched as the charge transfer changes with Mg insertion/extraction. The mechanism of such a charge-driven transformation originates from the versatile valence state of boron in its planar form. The discovery of these new physical phenomena suggests the design of a high-capacity magnesium-boron battery with theoretical energy density 876 mAh/g and 1550 Wh/L.

2011-10-01T23:59:59.000Z

133

"Kohn-Shamification" of the classical density-functional theory of inhomogeneous polar molecular liquids with application to liquid hydrogen chloride  

E-Print Network (OSTI)

The Gordian knot of density-functional theories for classical molecular liquids remains finding an accurate free-energy functional in terms of the densities of the atomic sites of the molecules. Following Kohn and Sham, we show how to solve this problem by considering noninteracting molecules in a set of effective potentials. This shift in perspective leads to an accurate and computationally tractable description in terms of simple three-dimensional functions. We also treat both the linear- and saturation- dielectric responses of polar systems, presenting liquid hydrogen chloride as a case study.

Johannes Lischner; T. A. Arias

2008-06-27T23:59:59.000Z

134

Correcting Density Functional Theory for Accurate Predictions of Compound Enthalpies of Formation: Fitted Elemental-Phase Reference Energies  

Science Conference Proceedings (OSTI)

Despite the great success that theoretical approaches based on density functional theory have in describing properties of solid compounds, accurate predictions of the enthalpies of formation ({Delta}H{sub f}) of insulating and semiconducting solids still remain a challenge. This is mainly due to incomplete error cancellation when computing the total energy differences between the compound total energy and the total energies of its elemental constituents. In this paper we present an approach based on GGA + U calculations, including the spin-orbit coupling, which involves fitted elemental-phase reference energies (FERE) and which significantly improves the error cancellation resulting in accurate values for the compound enthalpies of formation. We use an extensive set of 252 binary compounds with measured {Delta}H{sub f} values (pnictides, chalcogenides, and halides) to obtain FERE energies and show that after the fitting, the 252 enthalpies of formation are reproduced with the mean absolute error MAE = 0.054 eV/atom instead of MAE {approx} 0.250 eV/atom resulting from pure GGA calculations. When applied to a set of 55 ternary compounds that were not part of the fitting set the FERE method reproduces their enthalpies of formation with MAE = 0.048 eV/atom. Furthermore, we find that contributions to the total energy differences coming from the spin-orbit coupling can be, to a good approximation, separated into purely atomic contributions which do not affect {Delta}H{sub f}. The FERE method, hence, represents a simple and general approach, as it is computationally equivalent to the cost of pure GGA calculations and applies to virtually all insulating and semiconducting compounds, for predicting compound {Delta}H{sub f} values with chemical accuracy. We also show that by providing accurate {Delta}H{sub f} the FERE approach can be applied for accurate predictions of the compound thermodynamic stability or for predictions of Li-ion battery voltages.

Stevanovic, V.; Lany, S.; Zhang, X.; Zunger, A.

2012-03-15T23:59:59.000Z

135

A density functional theory study of the oxidation of methanol to formaldehyde over vanadia supported on silica, titania, and zirconia  

DOE Green Energy (OSTI)

Density functional theory was used to investigate the mechanism and kinetics of methanol oxidation to formaldehyde over vanadia supported on silica, titania, and zirconia. The catalytically active site was modeled as an isolated VO{sub 4} unit attached to the support. The calculated geometry and vibrational frequencies of the active site are in good agreement with experimental measurements both for model compounds and oxide-supported vanadia. Methanol adsorption is found to occur preferentially with the rupture of a V-O-M bond (M = Si, Ti, Zr) and with preferential attachment of a methoxy group to V. The vibrational frequencies of the methoxy group are in good agreement with those observed experimentally as are the calculated isobars. The formation of formaldehyde is assumed to occur via the transfer of an H atom of a methoxy group to the O atom of the V=O group. The activation energy for this process is found to be in the range of 199-214 kJ/mol and apparent activation energies for the overall oxidation of methanol to formaldehyde are predicted to lie in the range of 112-123 kJ/mol, which is significantly higher than that found experimentally. Moreover, the predicted turnover frequency (TOF) for methanol oxidation is found to be essentially independent of support composition, whereas experiments show that the TOF is 10{sup 3} greater for titania- and zirconia-supported vanadia than for silica-supported vanadia. Based on these findings, it is proposed that the formation of formaldehyde from methoxy groups may require pairs of adjacent VO{sub 4} groups or V{sub 2}O{sub 7} dimer structures.

Khaliullin, Rustam Z.; Bell, Alexis T.

2002-09-05T23:59:59.000Z

136

Quantitative Vapor-phase IR Intensities and DFT Computations to Predict Absolute IR Spectra based on Molecular Structure: I. Alkanes  

SciTech Connect

Recently recorded quantitative IR spectra of a variety of gas-phase alkanes are shown to have integrated intensities in both the C-H stretching and C-H bending regions that depend linearly on the molecular size, i.e. the number of C-H bonds. This result is well predicted from CH4 to C15H32 by DFT computations of IR spectra at the B3LYP/6-31+G(d,p) level of DFT theory. A simple model predicting the absolute IR band intensities of alkanes based only on structural formula is proposed: For the C-H stretching band near 2930 cm-1 this is given by (in km/mol): CH¬_str = (34±3)*CH – (41±60) where CH is number of C-H bonds in the alkane. The linearity is explained in terms of coordinated motion of methylene groups rather than the summed intensities of autonomous -CH2- units. The effect of alkyl chain length on the intensity of a C-H bending mode is explored and interpreted in terms of conformer distribution. The relative intensity contribution of a methyl mode compared to the total C-H stretch intensity is shown to be linear in the number of terminal methyl groups in the alkane, and can be used to predict quantitative spectra a priori based on structure alone.

Williams, Stephen D.; Johnson, Timothy J.; Sharpe, Steven W.; Yavelak, Veronica; Oats, R. P.; Brauer, Carolyn S.

2013-11-13T23:59:59.000Z

137

EERE PROJECT MANAGEMENT CENTER NFPA DFT1!lUIINATION  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

OFEN:rRGY OFEN:rRGY EERE PROJECT MANAGEMENT CENTER NFPA DFT1!lUIINATION Page 1 of2 RECIPIENT:Middlesex Community College STATE: MA PROJECf TITLE: Middlesex Community College - Geothermal Project Funding Opportunity Announcement Number Procurement Instrument Number NEPA Control Number CID Number N/A DE-EEOOOO323 GF0-0000323-002 EE323 Based on my review ofthe information concerning the proposed action, as NEPA Compliance Officer (authorized under DOE Order 4SI.IA), I have made the following determination: ex, EA, EIS APPENDIX AND NUMBER: Description: A9 Inf ormation gathering, analYSiS, and dissemination 82.1 Workplace enhancements B2.2 Building and equipment instrumentation Information gathering (including, but not limited to, literature surveys, inventories, site visits, and audils),

138

Optimization of a hybrid exchange-correlation functional for silicon carbides  

SciTech Connect

A hybrid exchange-correlation functional is optimized in order to accurately describe the nature of silicon carbides (SiC) in the framework of ab-initio calculations based on density functional theory (DFT), especially with an aim toward future applications in defect studies. It is shown that the Heyd-Scuseria-Ernzerhof (HSE) hybrid functional with the screening parameter of 0.15 -1 outperforms conventional exchange-correlation functionals and other popular hybrid functionals regarding description of band structures in SiC. High transferability is proven through assessment over various SiC polytypes, silicon and diamond. Excellent performance is also confirmed for other fundamental material properties including elastic constants and phonon frequency.

Oda, Takuji [University of Tennessee, Knoxville (UTK); Zhang, Yanwen [ORNL; Weber, William J [ORNL

2013-01-01T23:59:59.000Z

139

Accurate dipole polarizabilities for water clusters n=2-12 at the coupled-cluster level of theory and benchmarking of various density functionals.  

Science Conference Proceedings (OSTI)

The static dipole polarizabilities of water clusters (2 {le} N {le} 12) are determined at the coupled-cluster level of theory (CCSD). For the dipole polarizability of the water monomer it was determined that the role of the basis set is more important than that of electron correlation and that the basis set augmentation converges with two sets of diffuse functions. The CCSD results are used to benchmark a variety of density functionals while the performance of several families of basis sets (Dunning, Pople, and Sadlej) in producing accurate values for the polarizabilities was also examined. The Sadlej family of basis sets was found to produce accurate results when compared to the ones obtained with the much larger Dunning basis sets. It was furthermore determined that the PBE0 density functional with the aug-cc-pVDZ basis set produces overall remarkably accurate polarizabilities at a moderate computational cost.

Hammond, J.; Govind, N.; Kowalski, K.; Autschbach, J.; Xantheas, S.; PNNL; Univ. of Buffalo

2009-12-07T23:59:59.000Z

140

Sedimentation of a two-dimensional colloidal mixture exhibiting liquid-liquid and gas-liquid phase separation: a dynamical density functional theory study  

E-Print Network (OSTI)

We present dynamical density functional theory results for the time evolution of the density distribution of a sedimenting model two-dimensional binary mixture of colloids. The interplay between the bulk phase behaviour of the mixture, its interfacial properties at the confining walls, and the gravitational field gives rise to a rich variety of equilibrium and non-equilibrium morphologies. In the fluid state, the system exhibits both liquid-liquid and gas-liquid phase separation. As the system sediments, the phase separation significantly affects the dynamics and we explore situations where the final state is a coexistence of up to three different phases. Solving the dynamical equations in two-dimensions, we find that in certain situations the final density profiles of the two species have a symmetry that is different from that of the external potentials, which is perhaps surprising, given the statistical mechanics origin of the theory. The paper concludes with a discussion on this.

Alexandr Malijevsky; Andrew J. Archer

2013-09-17T23:59:59.000Z

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141

Duality Symmetric String and M-Theory  

E-Print Network (OSTI)

We review recent developments in duality symmetric string theory. We begin with the world sheet doubled formalism which describes strings in an extended space time with extra coordinates conjugate to winding modes. This formalism is T-duality symmetric and can accommodate non-geometric T-fold backgrounds which are beyond the scope of Riemannian geometry. Vanishing of the conformal anomaly of this theory can be interpreted as a set of spacetime equations for the background fields. These equations follow from an action principle that has been dubbed Double Field Theory (DFT). We review the aspects of generalised geometry relevant for DFT. We outline recent extensions of DFT and explain how, by relaxing the so-called strong constraint with a Scherk Schwarz ansatz, one can obtain backgrounds that simultaneously depend on both the regular and T-dual coordinates. This provides a purely geometric higher dimensional origin to gauged supergravities that arise from non-geometric compactification. We then turn to M-theory and describe recent progress in formulating an E_{n(n)} U-duality covariant description of the dynamics. We describe how spacetime may be extended to accommodate coordinates conjugate to brane wrapping modes and the construction of generalised metrics in this extend space that unite the bosonic fields of supergravity into a single object. We review the action principles for these theories and their novel gauge symmetries. We also describe how a Scherk Schwarz reduction can be applied in the M-theory context and the resulting relationship to the embedding tensor formulation of maximal gauged supergravities.

David S. Berman; Daniel C. Thompson

2013-06-11T23:59:59.000Z

142

Entanglement in GaAs and CdSe quantum dots: Exact calculations and DFT approximations  

Science Conference Proceedings (OSTI)

We consider two electrons confined in spherical GaAs and CdSe quantum dots and calculate their ground-state spatial entanglement exactly within a parabolic confinement model. We propose a perturbative scheme to approximate the above entanglement within ... Keywords: Density-functional theory, Entanglement, Quantum dots, Quantum information, Semiconductors

J. P. Coe; A. Sudbery; I. D'Amico

2009-03-01T23:59:59.000Z

143

A van der Waals density functional mapping of attraction in DNA dimers  

E-Print Network (OSTI)

The dispersion interaction between a pair of parallel DNA double-helix structures is investigated by means of the van der Waals density functional (vdW-DF) method. Each double-helix structure consists of an infinite repetition of one B-DNA coil with 10 base pairs. This parameter-free density functional theory (DFT) study illustrates the initial step in a proposed vdW-DF computational strategy for large biomolecular problems. The strategy is to first perform a survey of interaction geometries, based on the evaluation of the van der Waals (vdW) attraction, and then limit the evaluation of the remaining DFT parts (specifically the expensive study of the kinetic-energy repulsion) to the thus identified interesting geometries. Possibilities for accelerating this second step is detailed in a separate study. For the B-DNA dimer, the variation in van der Waals attraction is explored at relatively short distances (although beyond the region of density overlap) for a 360 degrees rotation. This study highlights the role...

Londero, Elisa; Schroder, Elsebeth

2013-01-01T23:59:59.000Z

144

Quasiparticle spectra from a nonempirical optimally tuned range-separated hybrid density functional  

SciTech Connect

We present a method for obtaining quasiparticle excitation energies from a DFT-based calculation, but with accuracy that is comparable to that of many-body perturbation theory within the GW approximation. The approach uses a range-separated hybrid density functional, with asymptotically exact and short-range fractional Fock exchange. The functional contains two parameters - the range separation and the short-range Fock fraction. Both are determined non-empirically, per system, based on satisfaction of exact physical constraints for the ionization potential and many-electron self-interaction, respectively. The accuracy of the method is demonstrated on the important benchmark molecule, 3,4,9,10-perylene-tetracarboxylic-dianydride (PTCDA), where it is shown to be the only non-empirical DFT-based method comparable to GW calculations. For any finite system, we envision that the approach could be useful directly as an inexpensive alternative to GW that offers good accuracy for both frontier and non-frontier quasiparticle excitation energies, opening the door to the studyof presently out of reach large-scale systems.

Refaely-Abramson, Sivan; Sharifzadeh, Sahar; Govind, Niranjan; Autschbach, Jochen; Neaton, Jeffrey B.; Baer, Roi; Kronik, Leeor

2012-11-28T23:59:59.000Z

145

Rigorous luminosity function determination in presence of a background: theory and application to two intermediate redshift clusters  

E-Print Network (OSTI)

In this paper we present a rigorous derivation of the luminosity function (LF) in presence of a background. Our approach is free from the logical contradictions of assigning negative values to positively defined quantities and avoid the use of incorrect estimates for the 68 % confidence interval (error bar). It accounts for Poisson fluctuations ignored in previous approaches and does not requires binning of the data. The method is extensible to more complex situations, does not require the existence of an environment--independent LF, and clarifies issues common to field LF derivations. We apply the method to two clusters of galaxies at intermediate redshift (z~0.3) with among the deepest and widest K_s observations ever taken. Finally, we point out short-comings of flip--flopping magnitudes.

S. Andreon; G. Punzi; A. Grado

2005-03-31T23:59:59.000Z

146

Density functional theory studies on theelectronic, structural, phonon dynamicaland thermo-stability properties of bicarbonates MHCO3, M D Li, Na, K  

Science Conference Proceedings (OSTI)

The structural, electronic, phonon dispersion and thermodynamic properties of MHCO3 (M D Li, Na, K) solids were investigated using density functional theory. The calculated bulk properties for both their ambient and the high-pressure phases are in good agreement with available experimental measurements. Solid phase LiHCO3 has not yet been observed experimentally. We have predicted several possible crystal structures for LiHCO3 using crystallographic database searching and prototype electrostatic ground state modeling. Our total energy and phonon free energy .FPH/ calculations predict that LiHCO3 will be stable under suitable conditions of temperature and partial pressures of CO2 and H2O. Our calculations indicate that the HCO􀀀 3 groups in LiHCO3 and NaHCO3 form an infinite chain structure through O#1; #1; #1;H#1; #1; #1;O hydrogen bonds. In contrast, the HCO􀀀 3 anions form dimers, .HCO􀀀 3 /2, connected through double hydrogen bonds in all phases of KHCO3. Based on density functional perturbation theory, the Born effective charge tensor of each atom type was obtained for all phases of the bicarbonates. Their phonon dispersions with the longitudinal optical–transverse optical splitting were also investigated. Based on lattice phonon dynamics study, the infrared spectra and the thermodynamic properties of these bicarbonates were obtained. Over the temperature range 0–900 K, the FPH and the entropies (S) of MHCO3 (M D Li, Na, K) systems vary as FPH.LiHCO3/ > FPH.NaHCO3/ > FPH.KHCO3/ and S.KHCO3/ > S.NaHCO3/ > S.LiHCO3/, respectively, in agreement with the available experimental data. Analysis of the predicted thermodynamics of the CO2 capture reactions indicates that the carbonate/bicarbonate transition reactions for Na and K could be used for CO2 capture technology, in agreement with experiments.

Duan, Yuhua; Zhang, Bo; Sorescu, Dan C.; Johnson, Karl; Majzoub, Eric H; Luebke, David R.

2012-07-01T23:59:59.000Z

147

Energy Density Functional for Nuclei and Neutron Stars  

Science Conference Proceedings (OSTI)

Background: Recent observational data on neutron star masses and radii provide stringent constraints on the equation of state of neutron rich matter [ Annu. Rev. Nucl. Part. Sci. 62 485 (2012)]. Purpose: We aim to develop a nuclear energy density functional that can be simultaneously applied to finite nuclei and neutron stars. Methods: We use the self-consistent nuclear density functional theory (DFT) with Skyrme energy density functionals and covariance analysis to assess correlations between observables for finite nuclei and neutron stars. In a first step two energy functionals a high density energy functional giving reasonable neutron properties, and a low density functional fitted to nuclear properties are matched. In a second step, we optimize a new functional using exactly the same protocol as in earlier studies pertaining to nuclei but now including neutron star data. This allows direct comparisons of performance of the new functional relative to the standard one. Results: The new functional TOV-min yields results for nuclear bulk properties (energy, rms radius, diffraction radius, and surface thickness) that are of the same quality as those obtained with the established Skyrme functionals, including SV-min. When comparing SV-min and TOV-min, isoscalar nuclear matter indicators vary slightly while isovector properties are changed considerably. We discuss neutron skins, dipole polarizability, separation energies of the heaviest elements, and proton and neutron drip lines. We confirm a correlation between the neutron skin of 208Pb and the neutron star radius. Conclusions: We demonstrate that standard energy density functionals optimized to nuclear data do not carry information on the expected maximum neutron star mass, and that predictions can only be made within an extremely broad uncertainty band. For atomic nuclei, the new functional TOV-min performs at least as well as the standard nuclear functionals, but it also reproduces expected neutron star data within assumed error bands. This functional is expected to yield more reliable predictions in the region of very neutron rich heavy nuclei.

Erler, J. [UTK/ORNL/German Cancer Research Center-Heidelberg; Horowitz, C. J. [UTK/ORNL/Indiana University; Nazarewicz, Witold [UTK/ORNL/University of Warsaw; Rafalski, M. [UTK/ORNL; Reinhard, P.-G. [Universitat Erlangen, Germany

2013-01-01T23:59:59.000Z

148

Linear-response and real-time time-dependent density functional theory studies of core-level near-edge x-ray absorption  

Science Conference Proceedings (OSTI)

We discuss our implementation and application of time-dependent density functional theory (TDDFT) to core-level near-edge absorption spectroscopy, using both linear-response (LR) and real-time (RT) approaches. We briefly describe our restricted window TDDFT (REWTDDFT) approach for core excitations which has also been reported by others groups. This is followed by a detailed discussion of real-time TDDFT techniques tailored to core excitations, including obtaining spectral information through delta-function excitation, post-processing time-dependent signals, and resonant excitation through quasi-monochromatic excitation. We present results for the oxygen K-edge of water and carbon dioxide; the carbon K-edge of carbon dioxide; the ruthenium L3-edge for the hexaamminerutheium(III) ion, including scalar relativistic corrections via the zeroth order regular approximation (ZORA); and the carbon and fluorine K-edges for a series of fluorobenzenes. In all cases, the calculated spectra are found to be in good agreement with experiment, requiring only a uniform shift on the order of a few percent. Real-time TDDFT visualization of excited state charge densities are used to visually examine the nature of each excitation, which gives insight into the effects of atoms bound to the absorbing center.

Lopata, Kenneth A.; Van Kuiken, Benjamin E.; Khalil, Munira; Govind, Niranjan

2012-09-03T23:59:59.000Z

149

Algorithmic information theory  

E-Print Network (OSTI)

We introduce algorithmic information theory, also known as the theory of Kolmogorov complexity. We explain the main concepts of this quantitative approach to defining `information'. We discuss the extent to which Kolmogorov's and Shannon's information theory have a common purpose, and where they are fundamentally different. We indicate how recent developments within the theory allow one to formally distinguish between `structural' (meaningful) and `random' information as measured by the Kolmogorov structure function, which leads to a mathematical formalization of Occam's razor in inductive inference. We end by discussing some of the philosophical implications of the theory.

Grunwald, Peter D

2008-01-01T23:59:59.000Z

150

Analytic progress in open string field theory  

E-Print Network (OSTI)

Open string field theory provides an action functional for open string fields, and it is thus a manifestly off-shell formulation of open string theory. The solutions to the equation of motion of open string field theory ...

Kiermaier, Michael Stefan

2009-01-01T23:59:59.000Z

151

Some nonrenormalizable theories are well-behaved  

E-Print Network (OSTI)

Some nonrenormalizable theories are less singular than all renormalizable theories. One can use lattice simulations to extract physical information from these nice nonrenormalizable theories. This paper discusses four nonrenormalizable theories that have finite euclidian and minkowskian Green's functions. Two of them have finite energy densities and describe scalar bosons of finite mass. The space of nonsingular nonrenormalizable theories is vast.

Kevin Cahill

2013-03-17T23:59:59.000Z

152

Density Functional Theory Study of CO Adsorption on Cu(I)-ZSM-5 Xiaobo Zheng,* Yihua Zhang, and Alexis T. Bell*  

E-Print Network (OSTI)

lithiumionsolvationby HMPA: Vandyshev, V.N.;Korolev,V.P.;Krest0v.G. A. Thermochim.Acta 1990,169,57.Goralski, P National Supercomputer Facility, a resource of the Center for Theory and Simulations in Science

Bell, Alexis T.

153

Density functional theory study of the structural, electronic, lattice dynamical, and thermodynamic properties of Li4SiO4 and its capability for CO2 capture  

SciTech Connect

The structural, electronic, lattice dynamical, optical, thermodynamic, and CO{sub 2} capture properties of monoclinic and triclinic phases of Li{sub 4}SiO{sub 4} are investigated by combining density functional theory with phonon lattice dynamics calculations. We found that these two phases have some similarities in their bulk and thermodynamic properties. The calculated bulk modulus and the cohesive energies of these two phases are close to each other. Although both of them are insulators, the monoclinic phase of Li{sub 4}SiO{sub 4} has a direct band gap of 5.24 eV while the triclinic Li{sub 4}SiO{sub 4} phase has an indirect band gap of 4.98 eV. In both phases of Li{sub 4}SiO{sub 4}, the s orbital of O mainly contributes to the lower-energy second valence band (VB{sub 2}) and the p orbitals contribute to the fist valence band (VB{sub 1}) and the conduction bands (CBs). The s orbital of Si mainly contributes to the lower portions of the VB1 and VB{sub 2}, and Si p orbitals mainly contribute to the higher portions of the VB{sub 1} and VB{sub 2}. The s and p orbitals of Li contribute to both VBs and to CBs, and Li p orbitals have a higher contribution than the Li s orbital. There is possibly a phonon soft mode existing in triclinic {gamma}-Li{sub 4}SiO{sub 4}; in the monoclinic Li{sub 4}SiO{sub 4}, there are three phonon soft modes, which correspond to the one type of Li disordered over a few sites. Their LO-TO splitting indicates that both phases of Li{sub 4}SiO{sub 4} are polar anisotropic materials. The calculated infrared absorption spectra for LO and TO modes are different for these two phases of Li{sub 4}SiO{sub 4}. The calculated relationships of the chemical potential versus temperature and CO{sub 2} pressure for reaction of Li{sub 4}SiO{sub 4} with CO{sub 2} shows that Li{sub 4}SiO{sub 4} could be a good candidate for a high-temperature CO{sub 2} sorbent while used for postcombustion capture technology.

Duan, Yuhua; Parlinski, K.

2011-01-01T23:59:59.000Z

154

Modeling surfaces in the context of pulsed-power : work functions, electron emission and dynamic response.  

SciTech Connect

The ability to quickly understand and deal with issues on ZR, or to virtually design a future ZX accelerator, requires a physics-based capability to simulate all key pulsed power components. Highly important for gas switches and transmission lines are surface phenomena: thermionic emission, photoemission, field emission, and ion-surface dynamics. These are complex processes even at normal conditions, when coupled to the dynamic environment in pulsed power components, the current state of the art of understanding is not at the level of science based predictive modeling. Modeling efforts at the macroscopic level (finite element based hydrodynamic simulations) require detailed information of these processes to yield more reliable results. This is the final report of an LDRD project in the science of extreme environments investment area; the project was focused on describing the physics of surfaces of materials of interest in pulsed-power components. We have calculated the temperature dependence of work functions for metals from first principles using density functional theory (DFT) as well as investigated the effect of initial oxidation and alloying. By using the GW method, we have gone beyond DFT to calculate work functions for Al. The GW work required base-lining the GW results for different systems, since GW lacks a description of total energy. Lastly, we investigated the more macroscopic physics of how a surface and bulk material responds to a very high current under a short time, representative for current loads in pulsed-power components, with emphasis on materials modeling. These simulations were made using two hydrodynamic codes, ALEGRA and MACH2, in order to focus on the materials models themselves.

Cochrane, Kyle Robert (Ktech Corporation, Albuquerque, NM); Chantrenne, Sophie (SAIC, Albuquerque, NM); Mattsson, Thomas Kjell Rene; Faleev, Sergey V. (SNAMI Inc., AL)

2009-09-01T23:59:59.000Z

155

Renormalized weak plasma turbulence theory  

SciTech Connect

A renormalized Vlasov turbulence theory, derived by neglecting a mode coupling term in the Direct Interaction Approximation, is discussed. The theory reduces correctly to weak turbulence theory; it predicts both diffusion and polarization effects of the turbulent medium on test particles, as well as the inverse effects of the test particles on the medium. A heuristic, physical algorithm is presented for constructing the equations. The theory of the renormalized dielectric function is reviewed.

Krommes, J.A.; Kleva, R.G.

1979-02-01T23:59:59.000Z

156

Electroweak Theory  

Science Conference Proceedings (OSTI)

The electroweak theory unifies two basic forces of nature: the weak force and electromagnetism. This 2007 book is a concise introduction to the structure of the electroweak theory and its applications. It describes the structure and properties of field ...

E. A. Paschos

2010-06-01T23:59:59.000Z

157

Transition-Metal Strings Templated on Boron-Doped Carbon Nanotubes: A DFT Investigation  

SciTech Connect

The binding nature, magnetic, and electronic properties of transition-metal (TM) monatomic chains anchored on boron-doped single-walled carbon nanotubes (B-SWCNTs) are studied using density-functional theory. The TM systems studied here include Au, Pt, Ru, Pd, Ag, Co, Ni, Cu, W, and Ti, which are well-known for their technical importance. In conjunction, prototype semiconducting SWCNT(8,0) and metallic SWCNT(6,6) were chosen to model the general features of B-doped SWCNTs. It is found that the TM-strings exhibit well-defined covalent bonds with the boron-doped SWCNTs, in contrast to the pristine SWCNTs. The TMstring/ B-SWCNT composites exhibit high stability and unexpected electronic properties, which are relevant to applications in nanoelectronics, spintronics, nanocatalysis, and sensor devices.

An, Wei; Turner, C. H.

2009-08-27T23:59:59.000Z

158

Experimental and DFT studies of initiation processes for butane isomerization over sulfated-zirconia catalysts  

SciTech Connect

Reaction kinetics studies were conducted of isobutane and n-butane isomerization at 423 K over sulfated-zirconia, with the butane feeds purified of olefins. Dihydrogen evolution was observed during butane isomerization over fresh catalysts, as well as over catalysts selectively poisoned by preadsorbed ammonia. Butane isomerization over sulfated-zirconia can be viewed as a surface chain reaction comprised of initiation, propagation, and termination steps. The primary initiation step in the absence of feed olefins is considered to be the dehydrogenation of butane over sulfated-zirconia, generating butenes which adsorb onto acid sites to form protonated olefinic species associated with the conjugate base form of the acid sites. Quantum-chemical calculations, employing density-functional theory, suggest that the dissociative adsorption of dihydrogen, isobutylene hydrogenation, and dissociative adsorption of isobutane are feasible over the sulfated-zirconia cluster, and these reactions take place over Zr-O sites.

Hong, Z.; Watwe, R.M.; Natal-Santiago, M.A.; Hill, J.M.; Dumesic, J.A. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Chemical Engineering] [Univ. of Wisconsin, Madison, WI (United States). Dept. of Chemical Engineering; Fogash, K.B. [Air Products and Chemicals, Inc., Allentown, PA (United States)] [Air Products and Chemicals, Inc., Allentown, PA (United States); Kim, B. [State Univ. of New York, Buffalo, NY (United States). Dept. of Chemical Engineering] [State Univ. of New York, Buffalo, NY (United States). Dept. of Chemical Engineering; Masqueda-Jimenez, B.I. [Univ. Autonoma de San Luis Potosi (Mexico). Centro de Investigacion y Estudios de Posgrado] [Univ. Autonoma de San Luis Potosi (Mexico). Centro de Investigacion y Estudios de Posgrado

1998-09-10T23:59:59.000Z

159

Ab Initio Enhanced CALPHAD Modeling of Actinide Rich Metallic ...  

Science Conference Proceedings (OSTI)

... Materials and Fuels for the Current and Advanced Nuclear Reactors III ... We show the standard functional of density functional theory (DFT) based on ...

160

Invariants from classical field theory  

Science Conference Proceedings (OSTI)

We introduce a method that generates invariant functions from perturbative classical field theories depending on external parameters. By applying our methods to several field theories such as Abelian BF, Chern-Simons, and two-dimensional Yang-Mills theory, we obtain, respectively, the linking number for embedded submanifolds in compact varieties, the Gauss' and the second Milnor's invariant for links in S{sup 3}, and invariants under area-preserving diffeomorphisms for configurations of immersed planar curves.

Diaz, Rafael [Grupo de Fisica-Matematica, Universidad Experimental Politecnica de las Fuerzas Armadas, Caracas 1010 (Venezuela); Leal, Lorenzo [Centro de Fisica Teorica y Computacional, Universidad Central de Venezuela, Caracas 1041-A (Venezuela)

2008-06-15T23:59:59.000Z

Note: This page contains sample records for the topic "functional theory dft" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Quantum Field Theory and Representation Theory  

E-Print Network (OSTI)

Quantum Field Theory and Representation Theory Peter Woit woit@math.columbia.edu Department of Mathematics Columbia University Quantum Field Theory and Representation Theory ­ p.1 #12;Outline of the talk · Quantum Mechanics and Representation Theory: Some History Quantum Field Theory and Representation Theory

Woit, Peter

162

Warped Conformal Field Theory  

E-Print Network (OSTI)

We study field theories in two spacetime dimensions invariant under a chiral scaling symmetry that acts only on right-movers. The local symmetries include one copy of the Virasoro algebra and a U(1) current algebra. This differs from the 2d conformal group, but in some respects is equally powerful in constraining the theory. In particular, the symmetries on a torus lead to modular covariance of the partition function, which is used to derive a universal formula for the asymptotic density of states. For an application we turn to the holographic description of black holes in quantum gravity, motivated by the fact that the symmetries in the near horizon geometry of any extremal black hole are identical to those of a 2d field theory with chiral scaling. We consider two examples: black holes in warped AdS_3 in topologically massive gravity, and in string theory. In both cases, the density of states in the 2d field theory reproduces the Bekenstein-Hawking entropy of black holes in the gravity theory.

Detournay, Stephane; Hofman, Diego M

2012-01-01T23:59:59.000Z

163

Warped Conformal Field Theory  

E-Print Network (OSTI)

We study field theories in two spacetime dimensions invariant under a chiral scaling symmetry that acts only on right-movers. The local symmetries include one copy of the Virasoro algebra and a U(1) current algebra. This differs from the 2d conformal group, but in some respects is equally powerful in constraining the theory. In particular, the symmetries on a torus lead to modular covariance of the partition function, which is used to derive a universal formula for the asymptotic density of states. For an application we turn to the holographic description of black holes in quantum gravity, motivated by the fact that the symmetries in the near horizon geometry of any extremal black hole are identical to those of a 2d field theory with chiral scaling. We consider two examples: black holes in warped AdS_3 in topologically massive gravity, and in string theory. In both cases, the density of states in the 2d field theory reproduces the Bekenstein-Hawking entropy of black holes in the gravity theory.

Stephane Detournay; Thomas Hartman; Diego M. Hofman

2012-10-01T23:59:59.000Z

164

Symmetry-adapted distributed approximating functionals: Theory and application to the ro-vibrational states of H{sub 3}{sup +}  

SciTech Connect

Symmetry-adapted Distributed Approximating Functionals (SADAFs) are derived and used to obtain a coordinate representation for the {und A}diabatically Adjusting {und P}rincipal Axis {und H}yperspherical (APH) coordinates kinetic energy operator. The resulting expressions are tested by computing (J=0) ro-vibrational states for the well-studied H{sub 3}{sup +} molecular ion system, by iterative diagonalization of the Hamiltonian matrix using the Arnoldi procedure. The SADAF representation and APH coordinate system are found to be computationally robust and accurate. {copyright} {ital 1999 American Institute of Physics.}

Iyengar, S.S. [Department of Chemistry, University of Houston, Houston, Texas 77204-5641 (United States); Parker, G.A. [Department of Physics, University of Oklahoma, Norman, Oklahoma (United States); Kouri, D.J. [Department of Chemistry and Department of Physics, University of Houston, Houston, Texas 77204-5641 (United States); Hoffman, D.K. [Department of Chemistry and Ames Laboratory, Iowa State University, Ames, Iowa 50011 (United States)

1999-06-01T23:59:59.000Z

165

Functions and fixed types: Biological and other functions in the post-adaptationist era  

Science Conference Proceedings (OSTI)

Among naturalistic theories of biological functions, only those that do not reduce functions to actual causal roles allow for a distinction of function and dysfunction. Most prominent among those theories are etiological theories of function, which refer ... Keywords: Adaptationism, Millikan, dysfunction, function, naturalization of norms, type fixation

Ulrich Krohs

2011-04-01T23:59:59.000Z

166

Gauge transformations in lattice chiral theories  

E-Print Network (OSTI)

We show that gauge-transformation properties of correlation functions in chiral gauge theories on the finite lattice are determined in a general way.

Werner Kerler

2004-12-21T23:59:59.000Z

167

Optimization Online - Nonsmooth Optimization for Production Theory  

E-Print Network (OSTI)

Dec 27, 2007 ... Abstract: Production theory needs generalizations so that it can incorporate broader class of production functions. A generalized Hotelling's ...

168

Materials Theory, Modeling and Simulation | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Functional Materials for Energy Chemistry and Physics at Interfaces Materials Synthesis from Atoms to Systems Materials Characterization Materials Theory and Simulation Quantum...

169

In Theory  

NLE Websites -- All DOE Office Websites (Extended Search)

5, 1998 5, 1998 Number 11 For every fundamental particle, the theory of supersymmetry proposes a supersymmetric partner, a "sparticle" in SUSY jargon. The electron, e, for example, has a SUSY spartner, the selectron ~ e. Would every Fermilab theorist have a SUSY "stheorist"? Probably not, but theorists worldwide will be watching Tevatron Run II for the first experimental evidence for SUSY. In Theory f INSIDE 2 Supersymmetry 7 Supersymmetry Workshop 8 MiniBooNE 10 Fishing 12 Paperless Papers 14 CDF Party The Fermilab Stheory Group ~ The Fermilab Theory Group by Meher Antia Without resorting to tricky mathematics or exotic physics, anyone can see that much of the stuff the world is made of has mass. Things can be touched and felt; they have some bulk, unlike, say, light which is intangible and

170

PP Theory  

NLE Websites -- All DOE Office Websites (Extended Search)

Present Theory of Present Theory of Fundamental Particles and Forces An Article Written Originally for Midlevel Teachers Back Before World War II, it was known that the nucleus was composed of closely packed protons and neutrons, but little was known about the "strong force" that kept them together. From 1950 to 1970, accelerators were built which were designed to probe nuclei with higher speed and more energetic, charged particles such as electrons and protons. The result was that hundreds of new particles were discovered and their properties defined. In 1963, a theory was proposed that a major group of these particles, called hadrons, could be thought of as made from a few, more fundamental particles, called quarks. Protons and neutrons are members of the hadron

171

Consequences of Structure and Composition for Catalysis by Solid and Bronsted Acids  

E-Print Network (OSTI)

thermochemical cycles of DPE and HAE were calculated using periodic gradient-corrected density functional theory (DFT) via the Vienna ab initio Simulation

Carr, Robert Ted

2012-01-01T23:59:59.000Z

172

Nuclear Fuels - Modeling  

Science Conference Proceedings (OSTI)

Mar 12, 2012... for the Current and Advanced Nuclear Reactors: Nuclear Fuels - Modeling .... Using density functional theory (DFT), we have predicted that ...

173

Is There a Nonrecursive Decidable Equational Theory?  

Science Conference Proceedings (OSTI)

The Church-Turing Thesis (CTT) is often paraphrased as ``every computable function is computable by means of a Turing machine.'' The author has constructed a family of equational theories that are not Turing-decidable, that is, given one of the theories, ... Keywords: Church-Turing Thesis, Turing decidability, effective procedure, pseudorecursive theory, quotidian procedure

Benjamin Wells

2002-05-01T23:59:59.000Z

174

Differential Pair Distribution Function Study of the Structure of Arsenate Adsorbed on Nanocrystalline [gamma]-Alumina  

SciTech Connect

Structural information is important for understanding surface adsorption mechanisms of contaminants on metal (hydr)oxides. In this work, a novel technique was employed to study the interfacial structure of arsenate oxyanions adsorbed on {gamma}-alumina nanoparticles, namely, differential pair distribution function (d-PDF) analysis of synchrotron X-ray total scattering. The d-PDF is the difference of properly normalized PDFs obtained for samples with and without arsenate adsorbed, otherwise identically prepared. The real space pattern contains information on atomic pair correlations between adsorbed arsenate and the atoms on {gamma}-alumina surface (Al, O, etc.). PDF results on the arsenate adsorption sample on {gamma}-alumina prepared at 1 mM As concentration and pH 5 revealed two peaks at 1.66 {angstrom} and 3.09 {angstrom}, corresponding to As-O and As-Al atomic pair correlations. This observation is consistent with those measured by extended X-ray absorption fine structure (EXAFS) spectroscopy, which suggests a first shell of As-O at 1.69 {+-} 0.01 {angstrom} with a coordination number of 4 and a second shell of As-Al at 3.13 {+-} 0.04 {angstrom} with a coordination number of 2. These results are in agreement with a bidentate binuclear coordination environment to the octahedral Al of {gamma}-alumina as predicted by density functional theory (DFT) calculation.

Li, Wei; Harrington, Richard; Tang, Yuanzhi; Kubicki, James D.; Aryanpour, Masoud; Reeder, Richard J.; Parise, John B.; Phillips, Brian L. (SBU); (Penn)

2012-03-15T23:59:59.000Z

175

Hydrogen Adsorption, Absorption and Diffusion on and in Transition Metal Surfaces: A DFT Study  

Science Conference Proceedings (OSTI)

Periodic, self-consistent DFT-GGA(PW91) calculations are used to study the interaction of hydrogen with different facets of seventeen transition metals—the (100) and (111) facets of face-centered cubic (fcc) metals, the (0001) facet of hexagonal-close packed (hcp) metals, and the (100) and (110) facets of body-centered cubic (bcc) metals. Calculated geometries and binding energies for surface and subsurface hydrogen are reported and are, in general, in good agreement with both previous modeling studies and experimental data. There are significant differences between the binding on the close-packed and more open (100) facets of the same metal. Geometries of subsurface hydrogen on different facets of the same metal are generally similar; however, binding energies of hydrogen in the subsurface of the different facets studied showed significant variation. Formation of surface hydrogen is exothermic with respect to gas-phase H? on all metals studied with the exception of Ag and Au. For each metal studied, hydrogen in its preferred subsurface state is always less stable than its preferred surface state. The magnitude of the activation energy for hydrogen diffusion from the surface layer into the first subsurface layer is dominated by the difference in the thermodynamic stability of these two states. Diffusion from the first subsurface layer to one layer further into the bulk does not generally have a large thermodynamic barrier but still has a moderate kinetic barrier. Despite the proximity to the metal surface, the activation energy for hydrogen diffusion from the first to the second subsurface layer is generally similar to experimentally-determined activation energies for bulk diffusion found in the literature. There are also some significant differences in the activation energy for hydrogen diffusion into the bulk through different facets of the same metal.

Ferrin, Peter A.; Kandoi, Shampa; Nilekar, Anand U.; Mavrikakis, Manos

2012-01-04T23:59:59.000Z

176

Quantum field theory without divergences  

E-Print Network (OSTI)

It is shown that loop divergences emerging in the Green functions in quantum field theory originate from correspondence of the Green functions to {\\em unmeasurable} (and hence unphysical) quantities. This is because no physical quantity can be measured in a point, but in a region, the size of which is constrained by the resolution of measuring equipment. The incorporation of the resolution into the definition of quantum fields $\\phi(x)\\to\\phi^{(A)}(x)$ and appropriate change of Feynman rules results in finite values of the Green functions. The Euclidean $\\phi^4$-field theory is taken as an example.

Altaisky, M V

2010-01-01T23:59:59.000Z

177

Quantum field theory without divergences  

E-Print Network (OSTI)

It is shown that loop divergences emerging in the Green functions in quantum field theory originate from correspondence of the Green functions to {\\em unmeasurable} (and hence unphysical) quantities. This is because no physical quantity can be measured in a point, but in a region, the size of which is constrained by the resolution of measuring equipment. The incorporation of the resolution into the definition of quantum fields $\\phi(x)\\to\\phi^{(A)}(x)$ and appropriate change of Feynman rules results in finite values of the Green functions. The Euclidean $\\phi^4$-field theory is taken as an example.

M. V. Altaisky

2010-02-12T23:59:59.000Z

178

Final Technical Report for DOE Grant, number DE-FG02-05ER15701; Probing Surface Chemistry Under Catalytic Conditions: Olefin Hydrogenation,Cyclization and Functionalization.  

Science Conference Proceedings (OSTI)

The specific goal of this work was to understanding the catalytic reactions pathways for the synthesis of vinyl acetate over Pd, Au and PdAu alloys. A combination of both experimental methods (X-ray and Auger spectroscopies, low-energy ion scattering (LEIS), low-energy electron diffraction (LEED) and theory (Density Functional Theory (DFT) calculations and Monte Carlo methods under various different reactions) were used to track the surface chemistry and the influence of alloying. The surface intermediates involved in the various reactions were characterized using reflection-absorption infrared spectroscopy and LEED to identify the nature of the surface species and temperature-programmed desorption (TPD) to follow the decomposition pathways and measure heats of adsorption. These results along with those from density functional theoretical calculations were used determine the kinetics for elementary steps. The results from this work showed that the reaction proceeds via the Samanos mechanism over Pd surfaces whereby the ethylene directly couples with acetate to form an acetoxyethyl intermediate that subsequently undergoes a beta-hydride elimination to form the vinyl acetate monomer. The presence of Au was found to modify the adsorption energies and surface coverages of important surface intermediates including acetate, ethylidyne and ethylene which ultimately influences the critical C-H activation and coupling steps. By controlling the surface alloy composition or structure one can begin to control the steps that control the rate and even the mechanism.

Neurock, Matthew

2011-05-26T23:59:59.000Z

179

Theory and Software  

NLE Websites -- All DOE Office Websites (Extended Search)

Theory and Software Home People Science Highlights Publications Seminars & Meetings Opportunities Advisory Committee Theory and Software Group (X-ray Science Division) The Theory...

180

Validation of Density Functional Theory for Materials  

Science Conference Proceedings (OSTI)

... One of the the crucial aspects in high-throughput computational screening of metal-organic frameworks (MOFs) for carbon capture and other ...

2013-07-18T23:59:59.000Z

Note: This page contains sample records for the topic "functional theory dft" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Salinas : theory manual.  

Science Conference Proceedings (OSTI)

Salinas provides a massively parallel implementation of structural dynamics finite element analysis, required for high fidelity, validated models used in modal, vibration, static and shock analysis of structural systems. This manual describes the theory behind many of the constructs in Salinas. For a more detailed description of how to use Salinas, we refer the reader to Salinas, User's Notes. Many of the constructs in Salinas are pulled directly from published material. Where possible, these materials are referenced herein. However, certain functions in Salinas are specific to our implementation. We try to be far more complete in those areas. The theory manual was developed from several sources including general notes, a programmer notes manual, the user's notes and of course the material in the open literature.

Walsh, Timothy Francis; Reese, Garth M.; Bhardwaj, Manoj Kumar

2011-11-01T23:59:59.000Z

182

ROHF Theory Made Simple  

E-Print Network (OSTI)

Restricted open-shell Hartree-Fock (ROHF) theory is formulated as a projected self-consistent unrestricted HF (UHF) model by mathematically constraining spin density eigenvalues. The resulting constrained UHF (CUHF) wave function is identical to that obtained from Roothaan's effective Fock operator. Our $\\alpha$ and $\\beta$ CUHF Fock operators are parameter-free and have canonical orbitals and orbital energies that are physically meaningful as in UHF, except for eliminating spin contamination. The present approach removes ambiguities in ROHF orbital energies and the non-uniqueness of methods that build upon them. We present benchmarks to demonstrate CUHF physical correctness and good agreement with experimental results.

Tsuchimochi, Takashi

2010-01-01T23:59:59.000Z

183

Synthesis modulo recursive functions  

Science Conference Proceedings (OSTI)

We describe techniques for synthesis and verification of recursive functional programs over unbounded domains. Our techniques build on top of an algorithm for satisfiability modulo recursive functions, a framework for deductive synthesis, and complete ... Keywords: inductive learning, satisfiability modulo theories, software synthesis

Etienne Kneuss, Ivan Kuraj, Viktor Kuncak, Philippe Suter

2013-10-01T23:59:59.000Z

184

Applicability of Effective-Medium Theories to problems of Scattering and Absorption by Nonhomogeneous Atmospheric Particles  

Science Conference Proceedings (OSTI)

Effective-medium theories yield effective dielectric functions (or, equivalently, refractive indices) of composite media. Such theories have been formulated that go beyond the Maxwell-Garnett and Bruggeman theories, which art restricted to media ...

Craig F. Bohren

1986-03-01T23:59:59.000Z

185

Spaces of Quantum Field Theories  

E-Print Network (OSTI)

The concept of a "space of quantum field theories" or "theory space" was set out in the 1970's in work of Wilson, Friedan and others. This structure should play an important role in organizing and classifying QFTs, and in the study of the string landscape, allowing us to say when two theories are connected by finite variations of the couplings or by RG flows, when a sequence of QFTs converges to another QFT, and bounding the amount of information needed to uniquely specify a QFT, enabling us to estimate their number. As yet we do not have any definition of theory space which can be used to make such arguments. In this talk, we will describe various concepts and tools which should be developed for this purpose, inspired by the analogous mathematical problem of studying the space of Riemannian manifolds. We state two general conjectures about the space of two-dimensional conformal field theories, and we define a distance function on this space, which gives a distance between any pair of theories, whether or not they are connected by varying moduli. Based on talks given at QTS6 (University of Kentucky), Erice, Texas A& M, and Northwestern University. To appear in the proceedings of QTS6.

Michael R. Douglas

2010-05-16T23:59:59.000Z

186

BNL | CFN: Theory & Computation  

NLE Websites -- All DOE Office Websites (Extended Search)

Theory and Computation Contact: Mark Hybertsen Advances in theory, numerical algorithms and computational capabilities have enabled an unprecedented opportunity for fundamental...

187

Grand Unified Theory  

NLE Websites -- All DOE Office Websites (Extended Search)

Grand Unified Theory Ungelste Rtsel Grand Unified Theory Heute besteht eines der Hauptziele der Teilchenphysik darin, die verschiedenen fundamentalen Krfte in einer Grossen...

188

String (Faden) Theorie  

NLE Websites -- All DOE Office Websites (Extended Search)

String Theory Ungelste Rtsel String (Faden) Theorie Die heutige Physik kennt gute Theorien wie Quantenmechanik, Relativittstheorie und Gravitation. Aber diese Theorien passen...

189

A first-principles density functional theory study of the electronic structural and thermodynamic properties of M2ZrO3 and M2CO3 (M=Na, K) and their capabilities for CO2 capture  

SciTech Connect

Alkali metal zirconates could be used as solid sorbents for CO{sub 2} capture. The structural, electronic, and phonon properties of Na{sub 2}ZrO{sub 3}, K{sub 2}ZrO{sub 3}, Na{sub 2}CO{sub 3}, and K{sub 2}CO{sub 3} are investigated by combining the density functional theory with lattice phonon dynamics. The thermodynamics of CO{sub 2} absorption/desorption reactions of these two zirconates are analyzed. The calculated results show that their optimized structures are in a good agreement with experimental measurements. The calculated band gaps are 4.339 eV (indirect), 3.641 eV (direct), 3.935 eV (indirect), and 3.697 eV (direct) for Na{sub 2}ZrO{sub 3}, K{sub 2}ZrO{sub 3}, Na{sub 2}CO{sub 3}, and K{sub 2}CO{sub 3}, respectively.The calculated phonon dispersions and phonon density of states for M{sub 2}ZrO{sub 3} and M{sub 2}CO{sub 3} (M = K, Na, Li) revealed that from K to Na to Li, their frequency peaks are shifted to high frequencies due to the molecular weight decreased from K to Li. From the calculated reaction heats and relationships of free energy change versus temperatures and CO{sub 2} pressures of the M{sub 2}ZrO{sub 3} (M = K, Na, Li) reacting with CO{sub 2}, we found that the performance of Na{sub 2}ZrO{sub 3} capturing CO{sub 2} is similar to that of Li{sub 2}ZrO{sub 3} and is better than that of K{sub 2}ZrO{sub 3}. Therefore, Na{sub 2}ZrO{sub 3} and Li{sub 2}ZrO{sub 3} are good candidates of high temperature CO{sub 2} sorbents and could be used for post combustion CO{sub 2} capture technologies.

Yuhua Duan

2012-01-01T23:59:59.000Z

190

1 String field theory  

E-Print Network (OSTI)

This elementary introduction to string field theory highlights the features and the limitations of this approach to quantum gravity as it is currently understood. String field theory is a formulation of string theory as a field theory in space-time with an infinite number of massive fields. Although existing constructions of string field theory require expanding around a fixed choice of space-time background, the theory is in principle background-independent, in the sense that different backgrounds can be realized as different field configurations in the theory. String field theory is the only string formalism developed so far which, in principle, has the potential to systematically address questions involving multiple asymptotically distinct string backgrounds. Thus, although it is not yet well defined as a quantum theory, string field theory may eventually be helpful for understanding questions related to cosmology in string theory. 1.1

W. Taylor

2006-01-01T23:59:59.000Z

191

QUANTIZATION OF THE GENERAL THEORY OF RELATIVITY  

SciTech Connect

It is possible to quantize most classical field theories by identifying the group of canonical transformations that maintain the covariance properties with a group of unitary transformations in Hilbert space that has the same commutator algebra. The computators among the canonical field variables are equal to the Dirac delta function times a factor that may be zero. But in the general theory of relativity the classical group of the canonical transformations that maintain the covariance properties of the theory has an invariance subgroup. The ambiguities thus introduced by the usual process of quantization can be avoided by the use of the Dirac quantization procedure for theories with constraints. An analogy between classical Dirac brackets and commutators is established, and an intrinsic coordinate system is fixed. This choice of local intrinsic coordinate conditions leads to commutators among the canonical field variables of the general theory of relativity that depend upon the Dirac delta function and its flrst seven derivatives. (auth)

Boardman, J.M.

1962-01-01T23:59:59.000Z

192

Theory Seminar Schedule  

NLE Websites -- All DOE Office Websites (Extended Search)

7-2008 7-2008 Click on a title to read an abstract, if available (underlined). 12 June 2008 Kristina Sviratcheva Louisiana State University kristina@rouge.phys.lsu.edu Symplectic Ab Initio No-Core Shell Model - Taming the Model Space Dilemma 5 June 2008 Wick Haxton INT, University of Washington haxton@u.washington.edu Probing Time-odd Moments in Atoms and Nuclei 1 May 2008 Wolfgang Bentz Tokai University, Japan bentz@keyaki.cc.u-tokai.ac.jp Fragmentation functions in an effective quark theory 17 April 2008 Special Time: 10:30am Dmitry G. Yakovlev Ioffe Physico-Technical Institute, St.Petersburg yak@astro.ioffe.rssi.ru Landau and Neutron Stars Tuesday 15 April 2008 Special Day Jochen Wambach GSI and TU Darmstadt J.Wambach@gsi.de Viscosity in the Nambu--Jona-Lasinio Model Tuesday 8 April 2008

193

Plasma Kinetic Theory  

Science Conference Proceedings (OSTI)

Kinetic Theory / Proceedings of the Ninth Carolus Magnus Summer School on Plasma and Fusion Energy Physics

B. Weyssow

194

Theory decision by decomposition  

Science Conference Proceedings (OSTI)

The topic of this article is decision procedures for satisfiability modulo theories (SMT) of arbitrary quantifier-free formulae. We propose an approach that decomposes the formula in such a way that its definitional part, including the theory, can be ... Keywords: Automated theorem proving: Rewriting, superposition, paramodulation, Satisfiability modulo theories: Decision procedures, combination of theories

Maria Paola Bonacina; Mnacho Echenim

2010-02-01T23:59:59.000Z

195

Model Theory and Quantum  

E-Print Network (OSTI)

Model Theory and Quantum Groups Sonia L'Innocente Model Theory and Quantum Groups Sonia L'Innocente (University of Mons) Model Theory and Quantum Groups 1 / 40 #12;Model Theory and Quantum Groups Sonia L quantum plane, submitted. This work is inspired by Ivo Herzog's paper: The pseudo-finite dimensional

Mons-Hainaut, Université de

196

Balance of Nanostructure and Bimetallic Interactions in Pt Model Fuel Cell Catalysts: An in Situ XAS and DFT Study  

DOE Green Energy (OSTI)

We have studied the effect of nanostructuring in Pt monolayer model electrocatalysts on a Rh(111) single-crystal substrate on the adsorption strength of chemisorbed species. In situ high energy resolution fluorescence detection X-ray absorption spectroscopy at the Pt L(3) edge reveals characteristic changes of the shape and intensity of the 'white-line' due to chemisorption of atomic hydrogen (H(ad)) at low potentials and oxygen-containing species (O/OH(ad)) at high potentials. On a uniform, two-dimensional Pt monolayer grown by Pt evaporation in ultrahigh vacuum, we observe a significant destabilization of both H(ad) and O/OH(ad) due to strain and ligand effects induced by the underlying Rh(111) substrate. When Pt is deposited via a wet-chemical route, by contrast, three-dimensional Pt islands are formed. In this case, strain and Rh ligand effects are balanced with higher local thickness of the Pt islands as well as higher defect density, shifting H and OH adsorption energies back toward pure Pt. Using density functional theory, we calculate O adsorption energies and corresponding local ORR activities for fcc 3-fold hollow sites with various local geometries that are present in the three-dimensional Pt islands.

Friebel, Daniel; Viswanathan, Venkatasubramanian; Miller, Daniel James; Anniyev, Toyli; Ogasawara, Hirohito; Larsen, Ask Hjorth; O'Grady, Christopher P.; Norskov, Jens K.; Nilsson, Anders

2012-05-31T23:59:59.000Z

197

NREL: Energy Sciences - Solid-State Theory  

NLE Websites -- All DOE Office Websites (Extended Search)

Solid-State Theory Solid-State Theory Image showing a roughly spherical red shape that looks like an apple that is floating within a yellow hemispherical shell. The shell is floating over a square below that shows an orange ring pattern bordered by yellow, then light blue, then darker blue. Square of the wave function (red) of a hole state in a spherical CdSe colloidal quantum dot (shape in yellow). The main research activities of the Solid-State Theory team within NREL's Theoretical Materials Science Group include the following: Theory of photovoltaic semiconductors Statistical and electronic theory of metal and semiconductor alloys Semiconductor nanostructures Inverse design of materials Computational methods in first-principles theories. This team provides the main theoretical thrust in the Center for Inverse

198

ELECTROSPINNING APPLICATIONS IN MECHANOCHEMISTRY AND MULTI-FUNCTIONAL HYDROGEL MATERIALS  

E-Print Network (OSTI)

function (EWF). Under the assumptions of this theory the Schrödinger equation for the EWF is given by

Braun, Paul

199

Reconstructing f(R) theory according to holographic dark energy  

E-Print Network (OSTI)

In this paper a connection between the holographic dark energy model and the $f(R)$ theory is established. We treat the $f(R)$ theory as an effective description for the holographic dark energy and reconstruct the function $f(R)$ with the parameter $c>1$, $c=1$ and $cR)$ theory, especially for the future evolution.

Xing Wu; Zong-Hong Zhu

2007-12-21T23:59:59.000Z

200

The generalized van der Waals theory of pure fluids and mixtures  

Science Conference Proceedings (OSTI)

This report discusses functional group analysis and partition function analysis of pure fluids and mixtures using generalized van der waals theory. (LSP)

Sandler, S.I.

1990-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "functional theory dft" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

ABJM theory as a Fermi gas  

E-Print Network (OSTI)

The partition function on the three-sphere of many supersymmetric Chern-Simons-matter theories reduces, by localization, to a matrix model. We develop a new method to study these models in the M-theory limit, but at all orders in the 1/N expansion. The method is based on reformulating the matrix model as the partition function of an ideal Fermi gas with a non-trivial, one-particle quantum Hamiltonian. This new approach leads to a completely elementary derivation of the N^{3/2} behavior for ABJM theory and N=3 quiver Chern-Simons-matter theories. In addition, the full series of 1/N corrections to the original matrix integral can be simply determined by a next-to-leading calculation in the WKB or semiclassical expansion of the quantum gas, and we show that, for several quiver Chern-Simons-matter theories, it is given by an Airy function. This generalizes a recent result of Fuji, Hirano and Moriyama for ABJM theory. It turns out that the semiclassical expansion of the Fermi gas corresponds to a strong coupling expansion in type IIA theory, and it is dual to the genus expansion. This allows us to calculate explicitly non-perturbative effects due to D2-brane instantons in the AdS background.

Marcos Marino; Pavel Putrov

2011-10-18T23:59:59.000Z

202

Scalar Quantum Field Theory in Disordered Media  

E-Print Network (OSTI)

A free massive scalar field in inhomogeneous random media is investigated. The coefficients of the Klein-Gordon equation are taken to be random functions of the spatial coordinates. The case of an annealed-like disordered medium, modeled by centered stationary and Gaussian processes, is analyzed. After performing the averages over the random functions, we obtain the two-point causal Green's function of the model up to one-loop. The disordered scalar quantum field theory becomes qualitatively similar to a $\\lambda\\phi^{4}$ self-interacting theory with a frequency-dependent coupling.

Arias, E; Krein, G; Menezes, G; Svaiter, N F

2011-01-01T23:59:59.000Z

203

Minority Influence Theory  

E-Print Network (OSTI)

The psychology of social impact. American Psychologist, 36,that later embodied in social impact theory (Latane, 1981)

Nemeth, Charlan Jeanne

2010-01-01T23:59:59.000Z

204

Quantum Physics Theory  

Science Conference Proceedings (OSTI)

Quantum Physics Theory. Summary: Theoretical work ... constant. The database is available at http://physics.nist.gov/hdel. Precise ...

2010-10-05T23:59:59.000Z

205

Plasma Kinetic Theory  

Science Conference Proceedings (OSTI)

Basic and Kinetic Theory / Proceedings of the Tenth Carolus Magnus Summer School on Plasma and Fusion Energy Physics

B. Weyssow

206

1992 Trieste Lectures on Topological Gauge Theory and Yang-Mills Theory  

E-Print Network (OSTI)

In these lecture notes we explain a connection between Yang-Mills theory on arbitrary Riemann surfaces and two types of topological field theory, the so called $BF$ and cohomological theories. The quantum Yang-Mills theory is solved exactly using path integral techniques. Explicit expressions, in terms of group representation theory, are obtained for the partition function and various correlation functions. In a particular limit the Yang-Mills theory devolves to the topological models and the previously determined correlation functions give topological information about the moduli spaces of flat connections. In particular, the partition function yields the volume of the moduli space for which an explicit expression is derived. These notes are self contained, with a basic introduction to the various ideas underlying the topological field theories. This includes some relatively new work on handling problems that arise in the presence of reducible connections which in turn forms the bridge between the various models under consideration. These notes are identical to those made available to participants of the 1992 summer school in Trieste, except for one or two additions added circa January 1993.

George Thompson

1993-05-24T23:59:59.000Z

207

Asymptotically Free Gauge Theories. I  

DOE R&D Accomplishments (OSTI)

Asymptotically free gauge theories of the strong interactions are constructed and analyzed. The reasons for doing this are recounted, including a review of renormalization group techniques and their application to scaling phenomena. The renormalization group equations are derived for Yang-Mills theories. The parameters that enter into the equations are calculated to lowest order and it is shown that these theories are asymptotically free. More specifically the effective coupling constant, which determines the ultraviolet behavior of the theory, vanishes for large space-like momenta. Fermions are incorporated and the construction of realistic models is discussed. We propose that the strong interactions be mediated by a "color" gauge group which commutes with SU(3)xSU(3). The problem of symmetry breaking is discussed. It appears likely that this would have a dynamical origin. It is suggested that the gauge symmetry might not be broken, and that the severe infrared singularities prevent the occurrence of non-color singlet physical states. The deep inelastic structure functions, as well as the electron position total annihilation cross section are analyzed. Scaling obtains up to calculable logarithmic corrections, and the naive lightcone or parton model results follow. The problems of incorporating scalar mesons and breaking the symmetry by the Higgs mechanism are explained in detail.

Wilczek, Frank; Gross, David J.

1973-07-00T23:59:59.000Z

208

Free Field Theory as a String Theory?  

E-Print Network (OSTI)

An approach to systematically implement open-closed string duality for free large $N$ gauge theories is summarised. We show how the relevant closed string moduli space emerges from a reorganisation of the Feynman diagrams contributing to free field correlators. We also indicate why the resulting integrand on moduli space has the right features to be that of a string theory on $AdS$.

Rajesh Gopakumar

2004-09-23T23:59:59.000Z

209

Three approaches to classical thermal field theory  

SciTech Connect

Research Highlights: > Classical thermal field theory admits three equivalent path integral formulations. > Classical Feynman rules can be derived for all three formulations. > Quantum Feynman rules reduce to classical ones at high temperatures. > Classical Feynman rules become much simpler when superfields are introduced. - Abstract: In this paper we study three different functional approaches to classical thermal field theory, which turn out to be the classical counterparts of three well-known different formulations of quantum thermal field theory: the closed-time path (CTP) formalism, the thermofield dynamics (TFD) and the Matsubara approach.

Gozzi, E., E-mail: gozzi@ts.infn.it [Department of Physics, University of Trieste, Strada Costiera 11, Miramare - Grignano, 34151 Trieste (Italy); INFN, Sezione di Trieste (Italy); Penco, R., E-mail: rpenco@syr.edu [Department of Physics, Syracuse University, Syracuse, NY 13244-1130 (United States)

2011-04-15T23:59:59.000Z

210

Aging Logarithmic Galilean Field Theories  

E-Print Network (OSTI)

We analytically compute correlation and response functions of scalar operators for the systems with Galilean and corresponding aging symmetries for general spatial dimensions $d$ and dynamical exponent $z$, along with their logarithmic and logarithmic squared extensions, using the gauge/gravity duality. These non-conformal extensions of the aging geometry are marked by two dimensionful parameters, eigenvalue $\\mathcal M$ of an internal coordinate and aging parameter $\\alpha$. We further perform systematic investigations on two-time response functions for general $d$ and $z$, and identify the growth exponent as a function of the scaling dimensions $\\Delta$ of the dual field theory operators and aging parameter $\\alpha$ in our theory. The initial growth exponent is only controlled by $\\Delta$, while its late time behavior by $\\alpha$ as well as $\\Delta$. These behaviors are separated by a time scale order of the waiting time. We attempt to make contact our results with some field theoretical growth models, such as Kim-Kosterlitz model at higher number of spatial dimensions $d$.

Seungjoon Hyun; Jaehoon Jeong; Bom Soo Kim

2013-03-29T23:59:59.000Z

211

Theory Modeling and Simulation  

SciTech Connect

Los Alamos has a long history in theory, modeling and simulation. We focus on multidisciplinary teams that tackle complex problems. Theory, modeling and simulation are tools to solve problems just like an NMR spectrometer, a gas chromatograph or an electron microscope. Problems should be used to define the theoretical tools needed and not the other way around. Best results occur when theory and experiments are working together in a team.

Shlachter, Jack [Los Alamos National Laboratory

2012-08-23T23:59:59.000Z

212

Lectures on String Theory  

E-Print Network (OSTI)

This is a one semester course on bosonic string theory aimed at beginning graduate students. The lectures assume a working knowledge of quantum field theory and general relativity. Contents: 1. The Classical String 2. The Quantum String 3. Open Strings and D-Branes 4. Introducing Conformal Field Theory 5. The Polyakov Path Integral and Ghosts 6. String Interactions 7. The Low-Energy Effective Action 8. Compactification and T-Duality

Tong, David

2009-01-01T23:59:59.000Z

213

Theory and Software Science  

NLE Websites -- All DOE Office Websites (Extended Search)

Science Goals The Theory and Software Group connects to the experimental programs at the Advanced Photon Source by the development of theoretical methodologies that provide new...

214

Atomic Theory of Lithium  

Science Conference Proceedings (OSTI)

... polarization-adjusted data were an excellent fit to theory, and the team's results agree with the latest and presumably best theoretical predictions. ...

2011-10-06T23:59:59.000Z

215

Introduction to String Theory  

E-Print Network (OSTI)

The aim of these notes is to give recent developments in string theory. In particular, we discuss the string spectrums, compactifications, brane physics and dualities.

Belhaj, Adil

2008-01-01T23:59:59.000Z

216

DFT Exercises - TMS  

Science Conference Proceedings (OSTI)

Mar 24, 2008 ... benzene silicon sodium graphite comparison of covalent, ionic, and metallic bonding. Van Hove singularities surface reconstruction on silicon

217

DFT repositories and informatics  

Science Conference Proceedings (OSTI)

... includes: Establishing best practices for future and current practitioners,; Developing data-sharing tools and repositories,; ...

2013-07-18T23:59:59.000Z

218

Quantum critical transport, duality, and M-theory  

E-Print Network (OSTI)

We consider charge transport properties of 2+1 dimensional conformal field theories at non-zero temperature. For theories with only Abelian U(1) charges, we describe the action of particle-vortex duality on the hydrodynamic-to-collisionless crossover function: this leads to powerful functional constraints for self-dual theories. For the n=8 supersymmetric, SU(N) Yang-Mills theory at the conformal fixed point, exact hydrodynamic-to-collisionless crossover functions of the SO(8) R-currents can be obtained in the large N limit by applying the AdS/CFT correspondence to M-theory. In the gravity theory, fluctuating currents are mapped to fluctuating gauge fields in the background of a black hole in 3+1 dimensional anti-de Sitter space. The electromagnetic self-duality of the 3+1 dimensional theory implies that the correlators of the R-currents obey a functional constraint similar to that found from particle-vortex duality in 2+1 dimensional Abelian theories. Thus the 2+1 dimensional, superconformal Yang Mills theory obeys a "holographic self duality" in the large N limit, and perhaps more generally.

Christopher P. Herzog; Pavel Kovtun; Subir Sachdev; Dam Thanh Son

2007-01-05T23:59:59.000Z

219

Investigations in gauge theories, topological solitons and string theories. Final report  

SciTech Connect

This is the Final Report on a supported research project on theoretical particle physics entitled ``Investigations in Gauge Theories, Topological Solitons and String Theories.`` The major theme of particle theory pursued has been within the rubric of the standard model, particularly on the interplay between symmetries and dynamics. Thus, the research has been carried out primarily in the context of gauge with or without chiral fermions and in effective chiral lagrangian field theories. The topics studied include the physical implications of abelian and non-abelian anomalies on the spectrum and possible dynamical symmetry breaking in a wide range of theories. A wide range of techniques of group theory, differential geometry and function theory have been applied to probe topological and conformal properties of quantum field theories in two and higher dimensions, the breaking of global chiral symmetries by vector-like gauge theories such as QCD,the phenomenology of a possibly strongly interacting Higgs sector within the minimal standard model, and the relevance of solitonic ideas to non-perturbative phenomena at SSC energies.

Not Available

1993-06-01T23:59:59.000Z

220

Creating a systemic functional grammar corpus from the Penn treebank  

Science Conference Proceedings (OSTI)

The lack of a large annotated systemic functional grammar (SFG) corpus has posed a significant challenge for the development of the theory. Automating SFG annotation is challenging because the theory uses a minimal constituency model, allocating as much ...

Matthew Honnibal; James R. Curran

2007-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "functional theory dft" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Introduction to string theory and conformal field theory  

Science Conference Proceedings (OSTI)

A concise survey of noncritical string theory and two-dimensional conformal field theory is presented. A detailed derivation of a conformal anomaly and the definition and general properties of conformal field theory are given. Minimal string theory, which is a special version of the theory, is considered. Expressions for the string susceptibility and gravitational dimensions are derived.

Belavin, A. A., E-mail: belavin@itp.ac.ru; Tarnopolsky, G. M., E-mail: Hetzif@yandex.r [Russian Academy of Sciences, Landau Institute for Theoretical Physics (Russian Federation)

2010-05-15T23:59:59.000Z

222

Analytical theory of intensity fluctuations in SASE  

SciTech Connect

Recent advances in SASE experiments stimulate interest in quantitative comparison of measurements with theory. Extending the previous analysis of the SASE intensity in guided modes, the authors provide an analytical description of the intensity fluctuations by calculating intensity correlation functions in the frequency domain. Comparison of the results with experiment yields new insight into the SASE process.

Yu, L.H.; Krinsky, S. [Brookhaven National Lab., Upton, NY (United States). National Synchrotron Light Source

1997-07-01T23:59:59.000Z

223

Generalised twisted partition functions  

E-Print Network (OSTI)

We consider the set of partition functions that result from the insertion of twist operators compatible with conformal invariance in a given 2D Conformal Field Theory (CFT). A consistency equation, which gives a classification of twists, is written and solved in particular cases. This generalises old results on twisted torus boundary conditions, gives a physical interpretation of Ocneanu's algebraic construction, and might offer a new route to the study of properties of CFT.

Petkova, V B

2001-01-01T23:59:59.000Z

224

Chern-Simons Theory on Seifert 3-Manifolds  

E-Print Network (OSTI)

We study Chern-Simons theory on 3-manifolds M that are circle-bundles over 2-dimensional orbifolds S by the method of Abelianisation. This method, which completely sidesteps the issue of having to integrate over the moduli space of non-Abelian flat connections, reduces the complete partition function of the non-Abelian theory on M to a 2-dimensional Abelian theory on the orbifold S which is easily evaluated.

Matthias Blau; George Thompson

2013-06-14T23:59:59.000Z

225

Finite BRST Transformations for the Bagger-Lambert-Gustavasson Theory  

E-Print Network (OSTI)

In this paper we analyse the Bagger-Lambert-Gustavsson (BLG) theory in $\\mathcal{N} =1$ superspace. Furthermore, we will construct the BRST transformations for this theory. These BRST transformations will be integrated out to obtain the finite field dependent version of BRST (FFBRST) transformations. We will also analyse the effect of the FFBRST transformations on the effective action. We will thus show that the FFBRST transformations can be used to relate generating functionals of the BLG theory in two different gauges.

Mir Faizal; Bhabani P Mandal; Sudhaker Upadhyay

2012-12-22T23:59:59.000Z

226

The Solar pp and hep Processes in Effective Field Theory  

E-Print Network (OSTI)

The strategy of modern effective field theory is exploited to pin down accurately the flux $S$ factors for the $pp$ and $hep$ processes in the Sun. The technique used is to combine the high accuracy established in few-nucleon systems of the "standard nuclear physics approach" (SNPA) and the systematic power counting of chiral perturbation theory (ChPT) into a consistent effective field theory framework. Using highly accurate wave functions obtained in the SNPA and working to \

T. -S. Park; K. Kubodera; D. -P. Min; M. Rho

2001-08-21T23:59:59.000Z

227

Lithium Local Pseudopotential Using  

E-Print Network (OSTI)

Lithium Local Pseudopotential Using DFT Sergio Orozco Student Advisor: Chen Huang Faculty Mentor Lithium LPS Test Lithium LPS #12;Density Functional Theory (DFT) Successful quantum mechanical approach (1979) #12;Building LPS for Lithium Create a LPS using NLPS density for Lithium Test LPS by comparing

Petta, Jason

228

Dirac Kirchhoff diffraction theory  

E-Print Network (OSTI)

Kirchhoff's scalar diffraction theory is applied throughout photon and electron optics. It is based on the stationary electromagnetic or Schr\\"odinger wave equation, and is useful in describing interference phenomena for both light and matter waves. Here, Kirchhoff's diffraction theory is derived from the relativistic Dirac equation, thus reformulated to work on Dirac spinors. The parallels with the "classic" scalar theory are highlighted, and a basic interpretation of the result obtained for the Fraunhofer diffraction limit is given. The goal of this paper is to emphasize the similarity between the two equations on the most fundamental level.

Ruben Van Boxem; Bart Partoens; Jo Verbeeck

2013-03-05T23:59:59.000Z

229

Dirac Kirchhoff diffraction theory  

E-Print Network (OSTI)

Kirchhoff's scalar diffraction theory is applied throughout photon and electron optics. It is based on the stationary electromagnetic or Schr\\"odinger wave equation, and is useful in describing interference phenomena for both light and matter waves. Here, Kirchhoff's diffraction theory is derived from the relativistic Dirac equation, thus reformulated to work on Dirac spinors. The parallels with the "classic" scalar theory are highlighted, and a basic interpretation of the result obtained for the Fraunhofer diffraction limit is given. The goal of this paper is to emphasize the similarity between the two equations on the most fundamental level.

Van Boxem, Ruben; Verbeeck, Jo

2013-01-01T23:59:59.000Z

230

ERGODIC THEORY OF PARABOLIC HORSESHOES MARIUSZ URBANSKI AND CHRISTIAN WOLF  

E-Print Network (OSTI)

ERGODIC THEORY OF PARABOLIC HORSESHOES MARIUSZ URBA´NSKI AND CHRISTIAN WOLF Abstract. In this paper parabolic fixed point and possibly also on Ws (). We call f a parabolic horseshoe map. In order to analyze of an embedded parabolic iterated function system and to apply the developed theory of the symbolic -finite

Urbanski, Mariusz

231

Dyson-Schwinger equations in the theory of computation  

E-Print Network (OSTI)

Following Manin's approach to renormalization in the theory of computation, we investigate Dyson-Schwinger equations on Hopf algebras, operads and properads of flow charts, as a way of encoding self-similarity structures in the theory of algorithms computing primitive and partial recursive functions and in the halting problem.

Colleen Delaney; Matilde Marcolli

2013-02-20T23:59:59.000Z

232

Contact Transformations and Hamiltonian Dynamics in Generalized Semigeostrophic Theories  

Science Conference Proceedings (OSTI)

This paper is concerned with the fundamental role played by contact transformations and their corresponding generating functions in determining the structure and dynamical properties of a very general class of semigeostrophic theories possessing ...

R. J. Purser

1993-06-01T23:59:59.000Z

233

Continuous Wavelet Transform in Quantum Field Theory  

E-Print Network (OSTI)

We describe the application of the continuous wavelet transform to calculation of the Green functions in quantum field theory: scalar $\\phi^4$ theory, quantum electrodynamics, quantum chromodynamics. The method of continuous wavelet transform in quantum field theory presented in M.Altaisky Phys. Rev. D81(2010)125003 for the scalar $\\phi^4$ theory, consists in substitution of the local fields $\\phi(x)$ by those dependent on both the position $x$ and the resolution $a$. The substitution of the action $S[\\phi(x)]$ by the action $S[\\phi_a(x)]$ makes the local theory into nonlocal one, and implies the causality conditions related to the scale $a$, the region causality C. Christensen and L. Crane, J.Math. Phys 46 (2005) 122502. These conditions make the Green functions $G(x_1,a_1,..., x_n,a_n)= $ finite for any given set of regions by means of an effective cutoff scale $A=\\min (a_1,...,a_n)$.

Altaisky, Mikhail V

2013-01-01T23:59:59.000Z

234

Joint Theory Institute  

NLE Websites -- All DOE Office Websites (Extended Search)

Program General Info Program General Info Registration Info Directions to Argonne Dynamics of Symmetry Breaking A Workshop sponsored by the ANL/UChicago Joint Theory Institute April 13-17, 2009 Argonne National Laboratory, IL The Joint Theory Institute (JTI) is a multi-disciplinary research institution jointly supported at the University of Chicago and Argonne National Laboratory to enhance collaborative research between both institutions in the broad area of theory. This year JTI sponsors a workshop the aim of which is to explore the dynamics of symmetry breaking in a broad range of systems from nuclear physics to string theory, using theoretical insights such as Dyson-Schwinger equations formalism, gauge/gravity duality and lattice QCD. We will focus on systems which exhibit dynamical symmetry breaking and will cover topics essential for understanding nonperturbative QCD and physics of quark-gluon plasma.

235

Argonne Physics Division - Theory Group  

NLE Websites -- All DOE Office Websites (Extended Search)

Argonne Theory Group: Postdoctoral Position The Theory Group in the Physics Division at Argonne National Laboratory is seeking exceptional candidates for a postdoctoral position...

236

Argonne Physics Division - Theory Group  

NLE Websites -- All DOE Office Websites (Extended Search)

23rd Annual Midwest Theory Get-Together 2010 Theory Group Theoretical research in Argonne's Physics Division addresses a broad range of problems involving the stucture and dynamics...

237

First-principles Investigation of Mg-Rare Earth Precipitates and ...  

Science Conference Proceedings (OSTI)

We investigate the coherency strain energy of Mg-?'' binary systems using first ... Using density functional theory (DFT), we explore the thermodynamic stability of ... Kinetic Monte Carlo Study of Fission Gas and Grain Growth in Nuclear Fuels.

238

PNNL-21407 Dynamic Processes in Biology, Chemistry, and Materials...  

NLE Websites -- All DOE Office Websites (Extended Search)

device CMOS complementary metal-oxide-semiconductor C s spherical aberration CZT CdZnTe DFT density functional theory DOE U.S. Department of Energy dpa displacements...

239

MEAM with Charge Transfer for TM Oxide Modeling  

Science Conference Proceedings (OSTI)

Abstract Scope, Transition metal (TM) oxides are important material with diverse applications including ... Density functional theory (DFT) modeling studies have provided useful bulk ... Atomistic Modeling of Radiation Damage in bcc Uranium.

240

Fock exchange in meson theories of nuclei  

Science Conference Proceedings (OSTI)

The Fock exchange term in meson field theories of nuclear systems is shown to arise from a two-loop ground-state self-energy diagram. Evaluation of this diagram gives the relativistic or semirelativistic analog of the Fock exchange energy; it differs from the nucleon-nucleon Fock energy in including retardation effects. In finite meson-field theories of nuclear systems, the variational nature of the meson-field analog of the Hartree-Fock energy functional can be further elucidated. 4 refs.

Bolsterli, M.

1986-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "functional theory dft" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Near the sill of the conformal window: gauge theories with fermions in two-index representations  

E-Print Network (OSTI)

We apply Schroedinger functional methods to two gauge theories with fermions in two-index representations: the SU(3) theory with Nf=2 adjoint fermions, and the SU(4) theory with Nf=6 fermions in the two-index antisymmetric representation. Each theory is believed to lie near the bottom of the conformal window for its respective representation. In the SU(3) theory we find a small beta function in strong coupling but we cannot confirm or rule out an infrared fixed point. In the SU(4) theory we find a hint of walking - a beta function that approaches the axis and then turns away from it. In both theories the mass anomalous dimension remains small even at the strongest couplings, much like the theories with fermions in the two-index symmetric representation investigated earlier.

Thomas DeGrand; Yigal Shamir; Benjamin Svetitsky

2013-07-09T23:59:59.000Z

242

The Particle Adventure | Unsolved Mysteries | String theory  

NLE Websites -- All DOE Office Websites (Extended Search)

String theory String theory Modern physics has good theories for quantum mechanics, relativity, and gravity. But these theories do not quite work with each other. There are...

243

An application of neutrix calculus to quantum field theory  

E-Print Network (OSTI)

Neutrices are additive groups of negligible functions that do not contain any constants except 0. Their calculus was developed by van der Corput and Hadamard in connection with asymptotic series and divergent integrals. We apply neutrix calculus to quantum field theory, obtaining finite renormalizations in the loop calculations. For renormalizable quantum field theories, we recover all the usual physically observable results. One possible advantage of the neutrix framework is that effective field theories can be accommodated. Quantum gravity theories appear to be more manageable.

Y. Jack Ng; H. van Dam

2005-02-17T23:59:59.000Z

244

Disposal: Science and Theory Disposal: Science and Theory  

E-Print Network (OSTI)

Disposal: Science and Theory #12;Disposal: Science and Theory Use of Composting · Composting has ­ British Columbia 2009 #12;Disposal: Science and Theory · Initial farm linked to NY LBM · Two additional and pile procedure Delmarva 2004 #12;Disposal: Science and Theory Delmarva 2004 · Composting used

Benson, Eric R.

245

Disposal: Science and Theory Disposal: Science and Theory  

E-Print Network (OSTI)

Disposal: Science and Theory #12;Disposal: Science and Theory Foam Used in Actual Outbreak · Water #12;Disposal: Science and Theory Water Based Foam Culling Demo · First large scale comparison · Two:46 (m:s) #12;Disposal: Science and Theory WV H5N2 AIV 2007 · AIV positive turkeys ­ 25,000 turkey farm

Benson, Eric R.

246

Disposal: Science and Theory Disposal: Science and Theory  

E-Print Network (OSTI)

Disposal: Science and Theory #12;Disposal: Science and Theory · El compostaje se ha usado como Virginia (2007) ­ British Columbia (2009) Uso del compostaje #12;Disposal: Science and Theory · Primera apilamiento Delmarva (2004) #12;Disposal: Science and Theory · El compostaje se usó para proteger una densa

Benson, Eric R.

247

Disposal: Science and Theory Disposal: Science and Theory  

E-Print Network (OSTI)

Disposal: Science and Theory #12;Disposal: Science and Theory Previous Research · Composting, et.al. 2005; Bendfeldt et al., 2006; DeRouchey et al., 2005) #12;Disposal: Science and Theory: Science and Theory Scientific Validation of Composting · Experiment 1 Impact of foam on composting

Benson, Eric R.

248

Disposal: Science and Theory Disposal: Science and Theory  

E-Print Network (OSTI)

Disposal: Science and Theory #12;Disposal: Science and Theory Poultry Farm Daily Disposal Methods 0;Disposal: Science and Theory First Composter in Delaware · Delmarva was of the first daily composting · 120 in USA over next 10 years #12;Disposal: Science and Theory Composting Procedure · Mixture ­ 1 ½ to 2

Benson, Eric R.

249

Disposal: Science and Theory Disposal: Science and Theory  

E-Print Network (OSTI)

Disposal: Science and Theory #12;Disposal: Science and Theory Brief History of Foam 2004 ­ Bud and foam 2009 ­ No advantage for gas #12;Disposal: Science and Theory What is foam? · What is fire fighting system. #12;Disposal: Science and Theory Foam Composition · Foam can include ­ Mixture of surfactants

Benson, Eric R.

250

Disposal: Science and Theory Disposal: Science and Theory  

E-Print Network (OSTI)

Disposal: Science and Theory #12;Disposal: Science and Theory · Compostaje de aves de corralRouchey et al., 2005) Investigación previa #12;Disposal: Science and Theory · Se ha evaluado y documentado el, bovino Investigación previa #12;Disposal: Science and Theory · Experimento nro. 1 Impacto de la espuma en

Benson, Eric R.

251

Disposal: Science and Theory Disposal: Science and Theory  

E-Print Network (OSTI)

Disposal: Science and Theory #12;Disposal: Science and Theory · Se ubica el carretón con el enfriamiento Ventiladores de túnel de viento #12;Disposal: Science and Theory · Se estaciona el remolque en uno: Science and Theory · Se usa un equipo de dos personas para hacer funcionar el sistema: ­ Operario del

Benson, Eric R.

252

Disposal: Science and Theory Disposal: Science and Theory  

E-Print Network (OSTI)

Disposal: Science and Theory #12;Disposal: Science and Theory · Opciones para la eliminación · ¿Qué compostaje durante brotes de enfermedades Lista de contenido #12;Disposal: Science and Theory "Ante un brote brotes de IIAP #12;Disposal: Science and Theory · En 2004, se despoblaron 100 millones de aves en todo el

Benson, Eric R.

253

Disposal: Science and Theory Disposal: Science and Theory  

E-Print Network (OSTI)

Disposal: Science and Theory #12;Disposal: Science and Theory · Las recomendaciones de campo se la espuma #12;Disposal: Science and Theory · Múltiples especies de aves pueden despoblarse con espuma cesación #12;Disposal: Science and Theory · Dentro de una especie, pueden existir variaciones ­ Los ánades

Benson, Eric R.

254

Disposal: Science and Theory Disposal: Science and Theory  

E-Print Network (OSTI)

Disposal: Science and Theory #12;Disposal: Science and Theory Summary · Foam is currently a viable ­ Foam application directly to cage #12;Disposal: Science and Theory Legal Status of Foam · Procedure depopulation, culling, and euthanasia #12;Disposal: Science and Theory Acknowledgements · USDA AICAP2 · USDA

Benson, Eric R.

255

Disposal: Science and Theory Disposal: Science and Theory  

E-Print Network (OSTI)

Disposal: Science and Theory #12;Disposal: Science and Theory Mass Emergency Composting · Basic ­ Create carcass and litter windrow #12;Disposal: Science and Theory Mass Emergency Composting · Basic cover ­ Clean and disinfect house ­ Sample for virus again #12;Disposal: Science and Theory Mass

Benson, Eric R.

256

Disposal: Science and Theory Disposal: Science and Theory  

E-Print Network (OSTI)

Disposal: Science and Theory #12;Disposal: Science and Theory · Gassing is a preferred #12;Disposal: Science and Theory Carbon Dioxide Gassing · Carbon dioxide (CO2) one of the standard sensitivity time #12;Disposal: Science and Theory · Argon-CO2 gas depopulation evaluated under laboratory

Benson, Eric R.

257

Disposal: Science and Theory Disposal: Science and Theory  

E-Print Network (OSTI)

Disposal: Science and Theory #12;Disposal: Science and Theory · El compostaje se define como la: Science and Theory · Compostaje óptimo ­ Relación carbono/nitrógeno (C:N): 20:1 a 35:1 ­ Contenido de Compostaje #12;Disposal: Science and Theory · Se ha utilizado satisfactoriamente una variedad de materiales

Benson, Eric R.

258

Disposal: Science and Theory Disposal: Science and Theory  

E-Print Network (OSTI)

Disposal: Science and Theory #12;Disposal: Science and Theory Foam Generator Setup · Drop off foam generator cart at one end of house #12;Disposal: Science and Theory Foam Generator Setup · Trailer parked generator attached to hose #12;Disposal: Science and Theory Foam Generation Begins · Team of two to operate

Benson, Eric R.

259

Disposal: Science and Theory Disposal: Science and Theory  

E-Print Network (OSTI)

Disposal: Science and Theory #12;Disposal: Science and Theory Foaming Options · Compressed Air Foam Systems (CAFS) · Foam Blower · Foam Generator · Nozzle Systems #12;Disposal: Science and Theory Compressed ­ Industry owned response team #12;Disposal: Science and Theory Commercial CAFS for Poultry · Poultry

Benson, Eric R.

260

Disposal: Science and Theory Disposal: Science and Theory  

E-Print Network (OSTI)

Disposal: Science and Theory #12;Disposal: Science and Theory 0 20 40 60 80 100 Compostaje #12;Disposal: Science and Theory · Delmarva fue de las primeras granjas en realizar el compostaje de en EE.UU. en los próximos 10 años. Pionera en compostaje en Delaware #12;Disposal: Science and Theory

Benson, Eric R.

Note: This page contains sample records for the topic "functional theory dft" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Disposal: Science and Theory Disposal: Science and Theory  

E-Print Network (OSTI)

Disposal: Science and Theory #12;Disposal: Science and Theory · Procedimiento básico ­ Desarrollar una pila de carcasas y lecho. Compostaje masivo de emergencia #12;Disposal: Science and Theory de emergencia #12;Disposal: Science and Theory · Desarrollar planes antes de que ocurra una

Benson, Eric R.

262

Disposal: Science and Theory Disposal: Science and Theory  

E-Print Network (OSTI)

Disposal: Science and Theory #12;Disposal: Science and Theory Composting · Composting is defined drop #12;Disposal: Science and Theory Composting · Optimal composting ­ Carbon to nitrogen ratio (C;Disposal: Science and Theory Compost Composition · A variety of supplemental carbon materials have been

Benson, Eric R.

263

Lax matrix solution of c=1 Conformal Field Theory  

E-Print Network (OSTI)

To a correlation function in a two-dimensional conformal field theory with the central charge c=1, we associate a matrix differential equation \\Psi'=L\\Psi, where the Lax matrix L is a matrix square root of the energy-momentum tensor. Then local conformal symmetry translates into isomonodromy of the differential equation. This provides a justification for the recently observed relation between four-point conformal blocks and solutions of the Painleve VI equation. This also provides a direct way to compute the three-point function of Runkel-Watts theory - the common c->1 limit of Minimal Models and Liouville theory.

Eynard, Bertrand

2013-01-01T23:59:59.000Z

264

Lax matrix solution of c=1 Conformal Field Theory  

E-Print Network (OSTI)

To a correlation function in a two-dimensional conformal field theory with the central charge c=1, we associate a matrix differential equation \\Psi'=L\\Psi, where the Lax matrix L is a matrix square root of the energy-momentum tensor. Then local conformal symmetry translates into isomonodromy of the differential equation. This provides a justification for the recently observed relation between four-point conformal blocks and solutions of the Painleve VI equation. This also provides a direct way to compute the three-point function of Runkel-Watts theory - the common c->1 limit of Minimal Models and Liouville theory.

Bertrand Eynard; Sylvain Ribault

2013-07-18T23:59:59.000Z

265

Near quantitative agreement of model free DFT- MD predictions with XAFS observations of the hydration structure of highly charged transition metal ions  

Science Conference Proceedings (OSTI)

DFT-MD simulations (PBE96 and PBE0) with MD-XAFS scattering calculations (FEFF9) show near quantitative agreement with new and existing XAFS measurements for a comprehensive series of transition metal ions which interact with their hydration shells via complex mechanisms (high spin, covalency, charge transfer, etc.). This work was supported by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences. Pacific Northwest National Laboratory (PNNL) is operated for the U.S. DOE by Battelle. A portion of the research was performed using EMSL, a national scientific user facility sponsored by the U.S. DOE's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory.

Fulton, John L.; Bylaska, Eric J.; Bogatko, Stuart A.; Balasubramanian, Mahalingam; Cauet, Emilie L.; Schenter, Gregory K.; Weare, John H.

2012-09-20T23:59:59.000Z

266

Heavy Quarks, QCD, and Effective Field Theory  

SciTech Connect

The research supported by this OJI award is in the area of heavy quark and quarkonium production, especially the application Soft-Collinear E#11;ective Theory (SCET) to the hadronic production of quarkonia. SCET is an e#11;ffective theory which allows one to derive factorization theorems and perform all order resummations for QCD processes. Factorization theorems allow one to separate the various scales entering a QCD process, and in particular, separate perturbative scales from nonperturbative scales. The perturbative physics can then be calculated using QCD perturbation theory. Universal functions with precise fi#12;eld theoretic de#12;nitions describe the nonperturbative physics. In addition, higher order perturbative QCD corrections that are enhanced by large logarithms can be resummed using the renormalization group equations of SCET. The applies SCET to the physics of heavy quarks, heavy quarkonium, and similar particles.

Thomas Mehen

2012-10-09T23:59:59.000Z

267

History of Unified Theories  

NLE Websites -- All DOE Office Websites (Extended Search)

Jahrelang haben Physiker nach vereinheitlichten Theorien gesucht - und Jahrelang haben Physiker nach vereinheitlichten Theorien gesucht - und diese auch gefunden. 1861-1865 James Maxwell, beschreibt in einem Artikel die Zusammenhänge zwischen elektrischen und magnetischen Feldern und vereinigt diese zur Theorie des Elektromagnetismus. Das führte zu den heute berühmten Maxwell'schen Gleichungen. 1881-1884 Heinrich Hertz demonstriert im Experiment die Existenz von Radiowellen und zeigt, dass Radiowellen und Licht elektromagnetische Wellen unterschiedlicher Frequenz darstellen - ein Faktum, das bereits von Maxwell in seiner Theorie vorhergesagt wurde. 1967-1970 Glashow, Salam und Weinberg schlagen eine Theorie vor, welche die elektromagnetische Wechselwirkung mit der schwachen WW vereinigt. Sie sagen die Masse des W Bosons, welches schwache Wechselwirkung - z.B.

268

Mathematical Quantum Field Theory and Renormalization Theory  

E-Print Network (OSTI)

This volume of Math-for-Industry Lecture Note Series is dedicated to Professor Izumi Ojima and Professor Kei-ichi Ito on the occasion of their sixtieth birthdays. Professor Izumi Ojima and Professor Kei-ichi Ito have organized a lot of interesting and advanced conferences, e.g., RIMS conference, on quantum field theory and related topics, and they have encouraged not only young but also senior scientists. We would like to express our hearty gratitude to Professor Izumi Ojima and Professor Kei-ichi Ito for their continuous encouragement to us, stimulating our works, innumerable, unbounded helpful comments to our scientific researches. This lecture note is collecting several research papers and survey articles contributed by invited speakers of the international conference

Renormalization

2009-01-01T23:59:59.000Z

269

New Insights into the Crystal and Electronic Structures of Li[subscript 1+x]V[subscript 1?x]O[subscript 2] from Solid State NMR, Pair Distribution Function Analyses, and First Principles Calculations  

Science Conference Proceedings (OSTI)

Pair distribution function (PDF) analyses of synchrotron data obtained for the anode materials Li{sub 1+x}V{sub 1-x}O{sub 2} (0 {le} x {le} 0.1) have been performed to characterize the short to medium range structural ordering. The data show clear evidence for the magnetically-induced distortion of the V sublattice to form trimers, the distortion persisting at even the highest excess Li content considered of x = 0.1. At least three distinct local environments were observed for the stoichiometric material LiVO{sub 2} in {sup 6}Li nuclear magnetic resonance (NMR) spectroscopy, the environments becoming progressively more disordered as the Li content increases. A two-dimensional Li-Li correlation NMR experiment (POST-C7) was used to identify the resonances corresponding to Li within the same layers. NMR spectra were acquired as a function of the state of charge, a distinct environment for Li in Li{sub 2}VO{sub 2} being observed. The results suggest that disorder within the Li layers (in addition to the presence of Li within the V layers as proposed by Armstrong et al. Nat. Mater.2011, 10, 223-229) may aid the insertion of Li into the Li{sub 1+x}V{sub 1-x}O{sub 2} phase. The previously little-studied Li{sub 2}VO{sub 2} phase was also investigated by hybrid density functional theory (DFT) calculations, providing insights into magnetic interactions, spin-lattice coupling, and Li hyperfine parameters.

Pourpoint, Frédérique; Hua, Xiao; Middlemiss, Derek S.; Adamson, Paul; Wang, Da; Bruce, Peter G.; Grey, Clare P. (SBU); (Cambridge); (St Andrews)

2012-10-29T23:59:59.000Z

270

Non-commutative Field Theory, Translational Invariant Products and Ultraviolet/Infrared Mixing  

E-Print Network (OSTI)

We review the Moyal and Wick-Voros products, and more in general the translation invariant non-commutative products, and apply them to classical and quantum field theory. We investigate phi^4 field theories calculating their Green's functions up to one-loop for the two- and four-point cases. We also review the connections of these theories with Drinfeld twists.

Galluccio, Salvatore

2010-01-01T23:59:59.000Z

271

Book Review of Stephen L. Adler's, "Quantum theory as an emergent phenomenon."  

E-Print Network (OSTI)

In Stephen Adler's book, "Quantum theory as an emergent phenomenon," the author starts from a classical mechanics structure and "derives" the formalism of quantum theory, together with wave function collapse dynamics, the latter providing the interpretation of quantum theory. A detailed outline of the author's argument is presented in this book review.

Philip Pearle

2006-02-07T23:59:59.000Z

272

A mass-dependent beta-function  

E-Print Network (OSTI)

Threshold effects related to fermion masses are considered for an all-order beta-function based on a background field momentum subtraction scheme. Far away from all thresholds, the suggested beta-function reduces to the conjectured all-order form inspired by the Novikov-Shifman-Vainshtein-Zakharov beta-function of N=1 supersymmetric gauge theories with a fixed integer number of fermion flavours. At (formally) infinite masses the corresponding pure Yang--Mills beta-function is recovered. We discuss applications to the phase diagram of non-Abelian field theories.

Dietrich, Dennis D

2009-01-01T23:59:59.000Z

273

Quantum Game Theory  

E-Print Network (OSTI)

Quantum game theory is the study of strategic behavior by agents with access to quantum technology. Broadly speaking, this technology can be employed in either of two ways: As part of a randomization device or as part of a communications protocol. We survey some of the main ideas from both branches of the subject.

Landsburg, Steven E

2011-01-01T23:59:59.000Z

274

Empirical Normal Modes versus Empirical Orthogonal Functions for Statistical Prediction  

Science Conference Proceedings (OSTI)

The theory of empirical normal modes (ENMs) for a shallow water fluid is developed. ENMs are basis functions that both have the statistical properties of empirical orthogonal functions (EOFs) and the dynamical properties of normal modes. In fact, ...

Gilbert Brunet; Robert Vautard

1996-12-01T23:59:59.000Z

275

ERGODIC THEORY OF PARABOLIC HORSESHOES MARIUSZ URBANSKI AND CHRISTIAN WOLF  

E-Print Network (OSTI)

ERGODIC THEORY OF PARABOLIC HORSESHOES MARIUSZ URBA´NSKI AND CHRISTIAN WOLF Abstract. In this paper parabolic fixed point and possibly also on Ws (). We call f a parabolic horseshoe map. In order to analyze the pressure function to the pressure of an embedded parabolic iterated function system and to apply

Wolf, Christian

276

Theory and Modeling of Weakly Bound/Physisorbed Materials  

E-Print Network (OSTI)

by physisorption: ­ CNT, fullerenes, carbon aerogels ­ Doping, Decorating, Charging · Accuracy of Methods: DFT, QMC CNT may have increased absorption3 · Carbon aerogels4 have exhibited 5 wt% for high surface areas, ~1

277

108- Density Functional Theory Study of Oxygen Vacancy Migration ...  

Science Conference Proceedings (OSTI)

125- Influence of Gas Flow Rate Ratio on the Structural Properties of a-SiC:H Prepared by ... 145- The Synergy of XRD and XRF in a Shale and Slate Analysis.

278

Density Functional Theory Based Calculations of Site Occupancy in ...  

Science Conference Proceedings (OSTI)

A comparison is made between the site occupancy behavior based on two .... First Principles Modeling of Shape Memory Alloy Magnetic Refrigeration Materials ... Forming-Crush Simulation Optimization Using Internal State Variable Model.

279

Density Functional Theory Simulations Predict New Materials for...  

NLE Websites -- All DOE Office Websites (Extended Search)

of these new physical phenomena suggests the design of a high- capacity magnesium-boron battery. NREL is a national laboratory of the U.S. Department of Energy, Office of Energy...

280

RICE UNIVERSITY Linear Scaling Density Functional Theory with  

E-Print Network (OSTI)

Scho¨nle1 , Dirk Kamin2 , Volker Westphal1 , Silvio O. Rizzoli2 , and Stefan W. Hell *; 1 1 Department laser (Fiber Drive, Blue Sky, Re- search, Milpitas, CA, USA) at a wavelength of 635 nm and it was turned by a re- search grant from the German Ministry for Education and Research (BMBF): Nanolive. MAL

Scuseria, Gustavo E.

Note: This page contains sample records for the topic "functional theory dft" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Theory Seminar Schedule  

NLE Websites -- All DOE Office Websites (Extended Search)

6-2007 6-2007 Click on a title to read an abstract, if available (underlined). 10 July 2007 Special Day: Tuesday, 3:00pm Robert Wiringa Argonne National Laboratory wiringa@theory.phy.anl.gov Dependence of nuclear binding on hadronic mass variation 3 July 2007 Special Day and Time: Tuesday, 10:30am Renato Higa University of Bonn, Germany higa@itkp.uni-bonn.de Coulomb interactions within Halo EFT 5 June 2007 Special Day and Time: Tuesday, 10.30am Omar Benhar Istituto Nazionale di Fisica Nucleare, Rome, Italy benhar@roma1.infn.it The equation of state of neutron star matter and gravitational wave emission 29 May 2007 Special Day: Tuesday Ulrich Mosel Giessen University, Germany Ulrich.Mosel@theo.physik.uni-giessen.de Hadrons in Medium - Theory meets experiment 10 May 2007

282

Disposal: Science and Theory Disposal: Science and Theory  

E-Print Network (OSTI)

Disposal: Science and Theory #12;Disposal: Science and Theory · Field recommendations based of activity ­ Corticosterone ­ EEG, ECG and motion studies · Large scale testing ­ Field scale units Science of Foam #12;Disposal: Science and Theory Cessation Time · Multiple bird species can be depopulated

Benson, Eric R.

283

Disposal: Science and Theory Disposal: Science and Theory  

E-Print Network (OSTI)

Disposal: Science and Theory #12;Disposal: Science and Theory Opciones para la producción de espuma espuma · Sistemas de boquilla #12;Disposal: Science and Theory Requisitos estimados: · Tiempo: 2 a 3 compactas ­ Equipo de respuesta propio de la industria Espuma de aire comprimido #12;Disposal: Science

Benson, Eric R.

284

Disposal: Science and Theory Disposal: Science and Theory  

E-Print Network (OSTI)

Disposal: Science and Theory #12;Disposal: Science and Theory 2004 ­ Participación de Bud Malone y la espuma 2009 ­ Ninguna ventaja para el gas Breve historia de la espuma #12;Disposal: Science sistema de boquilla ¿Qué es la espuma? #12;Disposal: Science and Theory · La espuma puede incluir: ­ Una

Benson, Eric R.

285

Disposal: Science and Theory Disposal: Science and Theory  

E-Print Network (OSTI)

Disposal: Science and Theory #12;Disposal: Science and Theory Table of Contents · Why Depopulate? · Depopulation Methods · Basics of Foam · Types of Foam Equipment · Science Behind Foam · Implementing Foam Depopulation · Use of Foam in the Field · Conclusions #12;Disposal: Science and Theory "When HPAI outbreaks

Benson, Eric R.

286

NUCLEAR THEORY WHITE PAPER 1995  

E-Print Network (OSTI)

We review the accomplishments of nuclear theory during the past five years and identify the future challenges and research opportunities. [Final, substantially revised version of the nuclear theory white paper

G. Bertsch; B. Mueller; J. Negele; J. Friar; V. Pandharipande

1995-02-15T23:59:59.000Z

287

Functional Specifications  

NLE Websites -- All DOE Office Websites (Extended Search)

Functional Specifications Functional Specifications Services Overview ECS Audio/Video Conferencing Fasterdata IPv6 Network Network Performance Tools (perfSONAR) ESnet OID Registry PGP Key Service Virtual Circuits (OSCARS) OSCARS Case Study Documentation User Manual FAQ Design Specifications Functional Specifications Notifications Publications Authorization Policy Default Attributes Message Security Clients For Developers Interfaces Links Hardware Requirements DOE Grids Service Transition Contact Us Technical Assistance: 1 800-33-ESnet (Inside the US) 1 800-333-7638 (Inside the US) 1 510-486-7600 (Globally) 1 510-486-7607 (Globally) Report Network Problems: trouble@es.net Provide Web Site Feedback: info@es.net Functional Specifications OSCARS Reservation Manager - Functional Specifications Year 3 Update (DRAFT)

288

Kinetic Theory of Plasma Waves  

Science Conference Proceedings (OSTI)

Kinetic Wave Theory / Proceedings of the Tenth Carolus Magnus Summer School on Plasma and Fusion Energy Physics

D. Van Eester; E. Lerche

289

Gauge theory and group representations  

SciTech Connect

The mathematical foundations of gauge theories based on indecomposable representations of space-time symmetry groups are investigated. In particular, twistors and singletons are given a uniform treatment as gauge theories of this type. This is a step toward geometrically unifying all representation based gauge theories. In addition, some implications with respect to the geometric construction of group representations are noted.

Nakashima, M.M.

1988-01-01T23:59:59.000Z

290

Quantum Field Theory Frank Wilczeky  

E-Print Network (OSTI)

Quantum Field Theory Frank Wilczeky Institute for Advanced Study, School of Natural Science, Olden Lane, Princeton, NJ 08540 I discuss the general principles underlying quantum eld theory, and attempt achieved and prospective. Possible limitations of quantum eld theory are viewed in the light of its history

Wilczek, Frank

291

Non-perturbative String Theory from Water Waves  

Science Conference Proceedings (OSTI)

We use a combination of a 't Hooft limit and numerical methods to find non-perturbative solutions of exactly solvable string theories, showing that perturbative solutions in different asymptotic regimes are connected by smooth interpolating functions. Our earlier perturbative work showed that a large class of minimal string theories arise as special limits of a Painleve IV hierarchy of string equations that can be derived by a similarity reduction of the dispersive water wave hierarchy of differential equations. The hierarchy of string equations contains new perturbative solutions, some of which were conjectured to be the type IIA and IIB string theories coupled to (4, 4k ? 2) superconformal minimal models of type (A, D). Our present paper shows that these new theories have smooth non-perturbative extensions. We also find evidence for putative new string theories that were not apparent in the perturbative analysis.

Iyer, Ramakrishnan; Johnson, Clifford V.; /Southern California U.; Pennington, Jeffrey S.; /SLAC

2012-06-14T23:59:59.000Z

292

An exact RG formulation of quantum gauge theory  

E-Print Network (OSTI)

A gauge invariant Wilsonian effective action is constructed for pure SU(N) Yang-Mills theory by formulating the corresponding flow equation. Manifestly gauge invariant calculations can be performed i.e. without gauge fixing or ghosts. Regularisation is implemented in a novel way which realises a spontaneously broken SU(N|N) supergauge theory. As an example we sketch the computation of the one-loop beta function, performed for the first time without any gauge fixing.

Tim R. Morris

2001-02-19T23:59:59.000Z

293

Open parabosonic string theory between two parallel Dp-branes  

Science Conference Proceedings (OSTI)

We investigate an open parabosonic string theory between two parallel Dp-branes. The spectrum is constructed and the partition function is derived. A common chord between the development of this latter and the degeneracy of the states for each mass level is obtained. The theory is consistent and with no tachyon. The Virasoro algebra is derived and compared to the one of the ordinary case.

Hamam, D.; Belaloui, N. [Laboratoire de Physique Theorique, Universite de Jijel (Algeria); Laboratoire de Physique Mathematique et Subatomique, Universite Mentouri Constantine (Algeria)

2012-06-27T23:59:59.000Z

294

The theory of shell-based Q-mappings in geometric function theory  

Science Conference Proceedings (OSTI)

Open, discrete Q-mappings in R{sup n}, n{>=}2, Q element of L{sup 1}{sub loc}, are proved to be absolutely continuous on lines, to belong to the Sobolev class W{sub loc}{sup 1,1}, to be differentiable almost everywhere and to have the N{sup -1}-property (converse to the Luzin N-property). It is shown that a family of open, discrete shell-based Q-mappings leaving out a subset of positive capacity is normal, provided that either Q has finite mean oscillation at each point or Q has only logarithmic singularities of order at most n-1. Under the same assumptions on Q it is proved that an isolated singularity x{sub 0} element of D of an open discrete shell-based Q-map f:D/{l_brace}x{sub 0{r_brace}{yields}}R-bar{sup n} is removable; moreover, the extended map is open and discrete. On the basis of these results analogues of the well-known Liouville, Sokhotskii-Weierstrass and Picard theorems are obtained. Bibliography: 34 titles.

Salimov, Ruslan R; Sevost'yanov, Evgenii A [Institute of Applied Mathematics and Mechanics, Ukraine National Academy of Sciences, Donetsk (Ukraine)

2010-08-12T23:59:59.000Z

295

Entanglement Entropy in Scalar Field Theory  

E-Print Network (OSTI)

Understanding the dependence of entanglement entropy on the renormalized mass in quantum field theories can provide insight into phenomena such as quantum phase transitions, since the mass varies in a singular way near the transition. Here we perturbatively calculate the entanglement entropy in interacting scalar field theory, focussing on the dependence on the field's mass. We study lambda phi^4 and g phi^3 theories in their ground state. By tracing over a half space, using the replica trick and position space Green's functions on the cone, we show that space-time volume divergences cancel and renormalization can be consistently performed in this conical geometry. We establish finite contributions to the entanglement entropy up to two-loop order, involving a finite area law. The resulting entropy is simple and intuitive: the free theory result in d=3 (that we included in an earlier publication) Delta S ~ A m^2 ln(m^2) is altered, to leading order, by replacing the bare mass m by the renormalized mass m_r eva...

Hertzberg, Mark P

2012-01-01T23:59:59.000Z

296

Green Functions of Relativistic Field Equations  

E-Print Network (OSTI)

In this paper, we restudy the Green function expressions of field equations. We derive the explicit form of the Green functions for the Klein-Gordon equation and Dirac equation, and then estimate the decay rate of the solution to the linear equations. The main motivation of this paper is to show that: (1). The formal solutions of field equations expressed by Green function can be elevated as a postulate for unified field theory. (2). The inescapable decay of the solution of linear equations implies that the whole theory of the matter world should include nonlinear interaction.

Ying-Qiu Gu

2006-12-20T23:59:59.000Z

297

Complex higher order derivative theories  

SciTech Connect

In this work is considered a complex scalar field theory with higher order derivative terms and interactions. A procedure is developed to quantize consistently this system avoiding the presence of negative norm states. In order to achieve this goal the original real scalar high order field theory is extended to a complex space attaching a complex total derivative to the theory. Next, by imposing reality conditions the complex theory is mapped to a pair of interacting real scalar field theories without the presence of higher derivative terms.

Margalli, Carlos A.; Vergara, J. David [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, Mexico 04510 DF (Mexico)

2012-08-24T23:59:59.000Z

298

Functional quantization  

E-Print Network (OSTI)

Data is rarely obtained for its own sake; oftentimes, it is a function of the data that we care about. Traditional data compression and quantization techniques, designed to recreate or approximate the data itself, gloss ...

Misra, Vinith

2008-01-01T23:59:59.000Z

299

Part Functions  

Science Conference Proceedings (OSTI)

Table 1   Functions served by parts...Mechanical power Shafts, connecting rods, gears Electricity Wires, lightbulb elements, resistors Provide a barrier (for example: reflect, cover, enclose,

300

N=2 supersymmetric gauge theories and quantum integrable systems  

E-Print Network (OSTI)

We study N=2 supersymmetric gauge theories on the product of a two-sphere and a cylinder. We show that the low-energy dynamics of a BPS sector of such a theory is described by a quantum integrable system, with the Planck constant set by the inverse of the radius of the sphere. If the sphere is replaced with a hemisphere, then our system reduces to an integrable system of the type studied by Nekrasov and Shatashvili. In this case we establish a correspondence between the effective prepotential of the gauge theory and the Yang-Yang function of the integrable system.

Yuan Luo; Meng-Chwan Tan; Junya Yagi

2013-10-02T23:59:59.000Z

Note: This page contains sample records for the topic "functional theory dft" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

N=2 supersymmetric gauge theories and quantum integrable systems  

E-Print Network (OSTI)

We study N=2 supersymmetric gauge theories on the product of a two-sphere and a cylinder. We show that the low-energy dynamics of a BPS sector of such a theory is described by a quantum integrable system, with the Planck constant set by the inverse of the radius of the sphere. If the sphere is replaced with a hemisphere, then our system reduces to an integrable system of the type studied by Nekrasov and Shatashvili. In this case we establish a correspondence between the effective prepotential of the gauge theory and the Yang-Yang function of the integrable system.

Luo, Yuan; Yagi, Junya

2013-01-01T23:59:59.000Z

302

Jordan cells in logarithmic limits of conformal field theory  

E-Print Network (OSTI)

It is discussed how a limiting procedure of conformal field theories may result in logarithmic conformal field theories with Jordan cells of arbitrary rank. This extends our work on rank-two Jordan cells. We also consider the limits of certain three-point functions and find that they are compatible with known results. The general construction is illustrated by logarithmic limits of (unitary) minimal models in conformal field theory. Characters of quasi-rational representations are found to emerge as the limits of the associated irreducible Virasoro characters.

Jorgen Rasmussen

2004-06-13T23:59:59.000Z

303

Effective Field Theory of Fractional Quantized Hall Nematics  

SciTech Connect

We present a Landau-Ginzburg theory for a fractional quantized Hall nematic state and the transition to it from an isotropic fractional quantum Hall state. This justifies Lifshitz-Chern-Simons theory - which is shown to be its dual - on a more microscopic basis and enables us to compute a ground state wave function in the symmetry-broken phase. In such a state of matter, the Hall resistance remains quantized while the longitudinal DC resistivity due to thermally-excited quasiparticles is anisotropic. We interpret recent experiments at Landau level filling factor {nu} = 7/3 in terms of our theory.

Mulligan, Michael; /MIT, LNS; Nayak, Chetan; /Station Q, UCSB; Kachru, Shamit; /Stanford U., Phys. Dept. /SLAC

2012-06-06T23:59:59.000Z

304

A DFT+U study of structure and reducibility of CenO2n-x (n?4, 0?x?n) nanoclusters  

Science Conference Proceedings (OSTI)

Equilibrium structures, stability and reducibility of Ce{sub n}O{sub 2n-x} (n=1,4, x=0{approx}4) nanoclusters have been studied using first principles DFT+U method. The planar rhombus Ce{sub 2}O{sub 2} structure is found to be the building block for the most stable Ce{sub n}O{sub 2n-x} clusters. The normalized binding energy of the cluster decreases linearly with increasing cluster size. The most stable stoichiometric Ce{sub n}O{sub 2n-x} clusters are electronically in closed-shell configuration (singlet), while the non-stoichiometric Ce{sub n}O{sub 2n-x} clusters are in a high spin state (triplet or quintet). The reduction energy, i.e., the energy required to remove an oxygen atom from a cluster, increases with the size and the extent of reduction. On the other hand, per electron based reduction energy for the cluster to reach the same formal oxidation state is independent of the cluster size.

Mei, Donghai; Ge, Qingfeng

2012-05-01T23:59:59.000Z

305

DUSEL Theory White Paper  

E-Print Network (OSTI)

The NSF has chosen the site for the Deep Underground Science and Engineering Laboratory (DUSEL) to be in Lead, South Dakota. In fact, the state of South Dakota has already stepped up to the plate and contributed its own funding for the proposed lab, see http://www.sanfordlaboratoryathomestake.org/index.html. The final decision by NSF for funding the Initial Suite of Experiments for DUSEL will be made early in 2009. At that time the NSF Science Board must make a decision. Of order 200 experimentalists have already expressed an interest in performing experiments at DUSEL. In order to assess the interest of the theoretical community, the Center for Cosmology and Astro-Particle Physics (CCAPP) at The Ohio State University (OSU) organized a 3-day DUSEL Theory Workshop in Columbus, Ohio from April 4 - 6, 2008. The workshop focused on the scientific case for six proposed experiments for DUSEL: long baseline neutrino oscillations, proton decay, dark matter, astrophysical neutrinos, neutrinoless double beta decay and N-Nbar oscillations. The outcome of this workshop is the DUSEL Theory White paper addressing the scientific case at a level which may be useful in the decision making process for policy makers at the NSF and in the U.S. Congress. In order to assess the physics interest in the DUSEL project we have posted the DUSEL Theory White paper on the following CCAPP link http://ccapp.osu.edu/whitepaper.html . Please read the white paper and, if you are interested, use the link to show your support by co-signing the white paper.

S. Raby; T. Walker; K. S. Babu; H. Baer; A. B. Balantekin; V. Barger; Z. Berezhiani; A. de Gouvea; R. Dermisek; A. Dolgov; P. Fileviez Perez; G. Gabadadze; A. Gal; P. Gondolo; W. Haxton; Y. Kamyshkov; B. Kayser; E. Kearns; B. Kopeliovich; K. Lande; D. Marfatia; R. N. Mohapatra; P. Nath; Y. Nomura; K. A. Olive; J. Pati; S. Profumo; R. Shrock; Z. Tavartkiladze; K. Whisnant; L. Wolfenstein

2008-10-24T23:59:59.000Z

306

Theory of amorphous ices  

E-Print Network (OSTI)

We use large-deviation theory to study nonequilibrium transitions between amorphous solids and liquid in an atomistic model of supercooled water. Along with nonequilibrium transitions between the ergodic liquid and two distinct amorphous solids, we establish coexistence between the two amorphous solids, a finding that is consistent with experiment. The phase diagram we predict includes a nonequilibrium triple point where the two amorphous phases and the liquid coexist. While the amorphous solids are long-lived and slowly-aging glasses, their melting leads quickly to the formation of ice. This irreversible behavior is demonstrated in our theoretical treatment and compared with experiment.

David T Limmer; David Chandler

2013-06-20T23:59:59.000Z

307

White Noise Theory  

E-Print Network (OSTI)

white noise space 3.2 Wick tensors 3.3 Hida-Kubo-Takenaka space 3.4 Kondratiev-Streit space 3.5 Cochran-Kuo-Sengupta space 4. Continuous versions and analytic extensions 4.1 Continuous versions 4.2 Analytic extensions 4.3 Integrable functions 4.4 Generalized functions induced by measures 4.5 Generalized Radon-Nikodym derivative 5. Characterization theorems 5.1 The S-transform 5.2 Characterization of generalized functions 5.3 Convergence of generalized functions 5.4 Characterization of test functions 5.5 Intrinsic topology for the space of test functions 6. Continuous operators and adjoints 6.1 Differential operators 6.2 Translation and scaling operators 6.3 Multiplication and Wick product 6.4 Fourier-Gauss transform 6.5 Extensions to CKS-spaces 7. Comments on other topics and applications 1 2 HUI-HSIUNG KUO 1. Introduction x1.1 What is white noise? White noise is a sound with equal intensity at all frequencies within a broad band. Rock music, the roar of a jet engine, and the noise...

Hui-Hsiung Kuo

1999-01-01T23:59:59.000Z

308

From Entropic Dynamics to Quantum Theory  

SciTech Connect

Non-relativistic quantum theory is derived from information codified into an appropriate statistical model. The basic assumption is that there is an irreducible uncertainty in the location of particles so that the configuration space is a statistical manifold. The dynamics then follows from a principle of inference, the method of Maximum Entropy. The concept of time is introduced as a convenient way to keep track of change. The resulting theory resembles both Nelson's stochastic mechanics and general relativity. The statistical manifold is a dynamical entity: its geometry determines the evolution of the probability distribution which, in its turn, reacts back and determines the evolution of the geometry. There is a new quantum version of the equivalence principle: 'osmotic' mass equals inertial mass. Mass and the phase of the wave function are explained as features of purely statistical origin.

Caticha, Ariel [Department of Physics, University at Albany-SUNY, Albany, NY 12222 (United States)

2009-12-08T23:59:59.000Z

309

Comprehending Quantum Theory from Quantum Fields  

E-Print Network (OSTI)

At the primary level of reality as described by quantum field theory, a fundamental particle like an electron represents a stable, discrete, propagating excited state of its underlying quantum field. QFT also tells us that the lowest vacuum state as well as the excited states of such a field is always very active with spontaneous, unpredictable quantum fluctuations. Also an underlying quantum field is known to be indestructible and immutable possessing the same value in each element of spacetime comprising the universe. These characteristics of the primary quantum fields together with the fact that the quantum fluctuations can be cogently substantiated to be quantum coherent throughout the universe provide a possible ontology of the quantum theory. In this picture, the wave function of a quantum particle represents the reality of the inherent quantum fluctuations at the core of the universe and endows the particle its counter intuitive quantum behavior.

Mani Bhaumik

2013-10-04T23:59:59.000Z

310

Duality in quantum field theory (and string theory)  

Science Conference Proceedings (OSTI)

These lectures give an introduction to duality in Quantum Field Theory. We discuss the phases of gauge theories and the implications of the electric-magnetic duality transformation to describe the mechanism of confinement. We review the exact results of N=1 supersymmetric QCD and the Seiberg-Witten solution of N=2 super Yang-Mills. Some of its extensions to String Theory are also briefly discussed.

Luis Álvarez-Gaumé; Frederic Zamora

1998-01-01T23:59:59.000Z

311

A New Lorentz Violating Nonlocal Field Theory From String-Theory  

E-Print Network (OSTI)

29] J. Polchinski, “String theory. Vol. 2: SuperstringNonlocal Field Theory From String-Theory Ori J. GanorNonlocal Field Theory From String-Theory Ori J. Ganor ?

Ganor, Ori J.

2009-01-01T23:59:59.000Z

312

New Results in Topological Field Theory and Abelian Gauge Theory  

E-Print Network (OSTI)

These are the lecture notes of a set of lectures delivered at the 1995 Trieste summer school in June. I review some recent work on duality in four dimensional Maxwell theory on arbitrary four manifolds, as well as a new set of topological invariants known as the Seiberg-Witten invariants. Much of the necessary background material is given, including a crash course in topological field theory, cohomology of manifolds, topological gauge theory and the rudiments of four manifold theory. My main hope is to wet the readers appetite, so that he or she will wish to read the original works and perhaps to enter this field.

George Thompson

1995-11-06T23:59:59.000Z

313

A lattice gauge theory model for graphene  

E-Print Network (OSTI)

In this Ph.D. thesis a model for graphene in presence of quantized electromagnetic interactions is introduced. The zero and low temperature properties of the model are studied using rigorous renormalization group methods and lattice Ward identities. In particular, it is shown that, at all orders in renormalized perturbation theory, the Schwinger functions and the response functions decay with interaction dependent anomalous exponents. Regarding the 2-point Schwinger function, the wave function renormalization diverges in the infrared limit, while the effective Fermi velocity flows to the speed of light. Concerning the response functions, those associated to a Kekul\\'e distortion of the honeycomb lattice and to a charge density wave instability are enhanced by the electromagnetic electron-electron interactions (their scaling in real space is depressed), while the lowest order correction to the scaling exponent of the density-density response function is vanishing. Then, the model in presence of a fixed Kekul\\'e distortion is studied, and it is shown that the interaction strongly renormalizes the effective amplitude of the lattice distortion. Finally, the effect of the electronic repulsion on the Peierls-Kekul\\'e instability is discussed by deriving a non-BCS gap equation, from which we find evidence that strong electromagnetic interactions facilitate the spontaneous distortion of the lattice and the opening of a gap. This thesis is based on joint work with A. Giuliani and V. Mastropietro.

Marcello Porta

2011-05-06T23:59:59.000Z

314

DUSEL Theory White Paper  

SciTech Connect

The scientific case for a Deep Underground Science and Engineering Laboratory [DUSEL] located at the Homestake mine in Lead, South Dakota is exceptional. The site of this future laboratory already claims a discovery for the detection of solar neutrinos, leading to a Nobel Prize for Ray Davis. Moreover this work provided the first step to our present understanding of solar neutrino oscillations and a chink in the armor of the Standard Model of particle physics. We now know, from several experiments located in deep underground experimental laboratories around the world, that neutrinos have mass and even more importantly this mass appears to fit into the framework of theories which unify all the known forces of nature, i.e. the strong, weak, electromagnetic and gravitational. Similarly, DUSEL can forge forward in the discovery of new realms of nature, housing six fundamental experiments that will test the frontiers of our knowledge: (1) Searching for nucleon decay (the decay of protons and neutrons predicted by grand unified theories of nature); (2) Searching for neutrino oscillations and CP violation by detecting neutrinos produced at a neutrino source (possibly located at Brookhaven National Laboratory and/or Fermi National Laboratory); (3) Searching for astrophysical neutrinos originating from the sun, from cosmic rays hitting the upper atmosphere or from other astrophysical sources, such a supernovae; (4) Searching for dark matter particles (the type of matter which does not interact electromagnetically, yet provides 24% of the mass of the Universe); (5) Looking for the rare process known as neutrino-less double beta decay which is predicted by most theories of neutrino mass and allows two neutrons in a nucleus to spontaneously change into two protons and two electrons; and (6) Searching for the rare process of neutron- anti-neutron oscillations, which would establish violation of baryon number symmetry. A large megaton water Cherenkov detector for neutrinos and nucleon decay, located in DUSEL and roughly 20 times the size of current detectors, can perform the first three of these experiments. The last 3 can utilize the unique environment afforded by DUSEL to perform the most sensitive tests to date. Any one of these experiments can greatly increase our knowledge of nature. The Deep Underground Science and Engineering Laboratory (DUSEL), with a Large Megaton Size Detector, is desperately needed to address a set of fundamental issues in particle and astrophysics.

Raby, S.; /Ohio State U.; Walker, T.; /Ohio State U. /Ohio State U., Dept. Astron. /Ohio State U., CCAPP; Babu, K.S.; /Oklahoma State U.; Baer, H.; /Florida State U.; Balantekin, A.B.; Barger, V.; /Wisconsin U., Madison; Berezhiani, Z.; /Gran Sasso; de Gouvea, A.; /Northwestern U.; Dermisek, R.; /Princeton U.; Dolgov, A.; /Moscow, ITEP /Ferrara U.; Fileviez Perez, P.; /Wisconsin U., Madison; Gabadadze, G.; /New York U.; Gal, A.; /Hebrew U.; Gondolo, P.; /Utah U.; Haxton, W.; /Washington U., Seattle; Kamyshkov, Y.; /Tennessee U.; Kayser, B.; /Fermilab; Kearns, E.; /Boston U.; Kopeliovich, B.; /Santa Maria U., Valparaiso; Lande, K.; /Pennsylvania U.; Marfatia, D.; /Kansas U. /Maryland U. /Northeastern U. /UC, Berkeley /LBL, Berkeley /Minnesota U. /SLAC /UC, Santa Cruz /SUNY, Stony Brook /Oklahoma State U. /Iowa State U. /Carnegie Mellon U.

2011-11-14T23:59:59.000Z

315

Partition Functions of Holographic Minimal Models  

E-Print Network (OSTI)

The partition function of the W_N minimal model CFT is computed in the large N 't Hooft limit and compared to the spectrum of the proposed holographic dual, a 3d higher spin gravity theory coupled to massive scalar fields. At finite N, the CFT contains additional light states that are not visible in the perturbative gravity theory. We carefully define the large N limit, and give evidence that, at N = infinity, the additional states become null and decouple from all correlation functions. The surviving states are shown to match precisely (for all values of the 't Hooft coupling) with the spectrum of the higher spin gravity theory. The agreement between bulk and boundary is partially explained by symmetry considerations involving the conjectured equivalence between the W_N algebra in the large N limit and the higher spin algebra of the Vasiliev theory.

Gaberdiel, Matthias R; Hartman, Thomas; Raju, Suvrat

2011-01-01T23:59:59.000Z

316

Partition Functions of Holographic Minimal Models  

E-Print Network (OSTI)

The partition function of the W_N minimal model CFT is computed in the large N 't Hooft limit and compared to the spectrum of the proposed holographic dual, a 3d higher spin gravity theory coupled to massive scalar fields. At finite N, the CFT contains additional light states that are not visible in the perturbative gravity theory. We carefully define the large N limit, and give evidence that, at N = infinity, the additional states become null and decouple from all correlation functions. The surviving states are shown to match precisely (for all values of the 't Hooft coupling) with the spectrum of the higher spin gravity theory. The agreement between bulk and boundary is partially explained by symmetry considerations involving the conjectured equivalence between the W_N algebra in the large N limit and the higher spin algebra of the Vasiliev theory.

Matthias R. Gaberdiel; Rajesh Gopakumar; Thomas Hartman; Suvrat Raju

2011-06-09T23:59:59.000Z

317

16. Heavy-Quark and Soft-Collinear Effective Theory 1 16. Heavy-Quark and Soft-Collinear Effective Theory  

E-Print Network (OSTI)

16. Heavy-Quark and Soft-Collinear Effective Theory 1 16. Heavy-Quark and Soft-Collinear Effective the quantum fluctuations of such heavy particles are "integrated out" from the generating functional integral.lbl.gov) February 16, 2012 14:07 #12;2 16. Heavy-Quark and Soft-Collinear Effective Theory 16.2. Heavy

318

Fermilab | Science at Fermilab | Theory  

NLE Websites -- All DOE Office Websites (Extended Search)

Theory Theorist Rakhi Mahbubani Theorist Rakhi Mahbubani Theoretical physics at Fermilab Fermilab is a laboratory where advances in particle physics, astrophysics and cosmology...

319

Argonne Physics Division - Theory Group  

NLE Websites -- All DOE Office Websites (Extended Search)

Administration Secretary: Debbie Morrison EMail: morrison@anl.gov Phone: 630252-4100 Fax: 630252-3903 Address: Theory Group Physics Division, Building 203 Argonne National...

320

Vortex operators in gauge field theories  

SciTech Connect

Several related aspects of the 't Hooft vortex operator are studied. The current picture of the vacuum of quantum chromodynamics, the idea of dual field theories, and the idea of the vortex operator are reviewed first. The Abelian vortex operator written in terms of elementary fields and the calculation of its Green's functions are considered. A two-dimensional solvable model of a Dirac string is presented. The expression of the Green's functions more neatly in terms of Wu and Yang's geometrical idea of sections is addressed. The renormalization of the Green's functions of two kinds of Abelian looplike operators, the Wilson loop and the vortex operator, is studied; for both operators only an overall multiplicative renormalization is needed. In the case of the vortex this involves a surprising cancellation. Next, the dependence of the Green's functions of the Wilson and 't Hooft operators on the nature of the vacuum is discussed. The cluster properties of the Green's functions are emphasized. It is seen that the vortex operator in a massive Abelian theory always has surface-like clustering. The form of Green's functions in terms of Feynman graphs is the same in Higgs and symmetric phases; the difference appears in the sum over all tadpole trees. Finally, systems having fields in the fundamental representation are considered. When these fields enter only weakly into the dynamics, a vortex-like operator is anticipated. Any such operator can no longer be local looplike, but must have commutators at long range. A U(1) lattice gauge theory with two matter fields, one singly charged (fundamental) and one doubly charged (adjoint), is examined. When the fundamental field is weakly coupled, the expected phase transitions are found. When it is strongly coupled, the operator still appears to be a good order parameter, a discontinuous change in its behavior leads to a new phase transition. 18 figures.

Polchinski, J.

1980-07-01T23:59:59.000Z

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321

Disposal: Science and Theory Disposal: Science and Theory  

E-Print Network (OSTI)

Disposal: Science and Theory #12;Disposal: Science and Theory Table of Contents · Disposal options emergency mortality composting procedure · Use of composting during outbreaks #12;Disposal: Science and disinfection of farms and surveillance around affected flocks. " USDA APHIS VS EMD, 2007 #12;Disposal: Science

Benson, Eric R.

322

Granular Rough Theory: A representation semantics oriented theory of roughness  

Science Conference Proceedings (OSTI)

The present work is an archival paper for a series of contributions proposed in last few years on building a theory of roughness over pure mereological relations among information granules. There are five major efforts taken in the present paper: (1) ... Keywords: Granular Representation Calculus, Granular Rough Theory, Granular-Rough Computational Web Intelligence

Bo Chen; Ming Sun; Mingtian Zhou

2009-03-01T23:59:59.000Z

323

FLINT Fast Library for Number Theory  

E-Print Network (OSTI)

FLINT is a C library of functions for doing number theory. It is highly optimised and can be compiled on numerous platforms. FLINT also has the aim of providing support for multicore and multiprocessor computer architectures, though we do not yet provide this facility. FLINT is currently maintained by William Hart of Warwick University in the UK. Its main authors are William Hart, Sebastian Pancratz, Fredrik Johannson, Andy Novocin and David Harvey (no longer active). FLINT 2 and following should compile on any machine with GCC and a standard GNU toolchain, however it is specially optimized for x86 (32 and 64 bit) machines. As of version 2.0 FLINT required GCC version 2.96 or later, MPIR 2.1.1 or later and MPFR 3.0.0 or later. FLINT is supplied as a set of modules, fmpz, fmpz_poly, etc., each of which can be linked to a C program making use of their functionality. All of the functions in FLINT have a corresponding test function provided in an appropriately named test le. For example, the function fmpz_poly_add located in fmpz_poly/add.c has test code in the le fmpz_poly/test/t-add.c.

William Hart; *Fredrik Johansson; Sebastian Pancratz

2011-01-01T23:59:59.000Z

324

Thermal field theories and shifted boundary conditions  

E-Print Network (OSTI)

The analytic continuation to an imaginary velocity of the canonical partition function of a thermal system expressed in a moving frame has a natural implementation in the Euclidean path-integral formulation in terms of shifted boundary conditions. The Poincare' invariance underlying a relativistic theory implies a dependence of the free-energy on the compact length L_0 and the shift xi only through the combination beta=L_0(1+xi^2)^(1/2). This in turn implies that the energy and the momentum distributions of the thermal theory are related, a fact which is encoded in a set of Ward identities among the correlators of the energy-momentum tensor. The latter have interesting applications in lattice field theory: they offer novel ways to compute thermodynamic potentials, and a set of identities to renormalize non-perturbatively the energy-momentum tensor. At fixed bare parameters the shifted boundary conditions also provide a simple method to vary the temperature in much smaller steps than with the standard procedure.

Leonardo Giusti; Harvey B. Meyer

2013-10-29T23:59:59.000Z

325

Thermal field theories and shifted boundary conditions  

E-Print Network (OSTI)

The analytic continuation to an imaginary velocity of the canonical partition function of a thermal system expressed in a moving frame has a natural implementation in the Euclidean path-integral formulation in terms of shifted boundary conditions. The Poincare' invariance underlying a relativistic theory implies a dependence of the free-energy on the compact length L_0 and the shift xi only through the combination beta=L_0(1+xi^2)^(1/2). This in turn implies that the energy and the momentum distributions of the thermal theory are related, a fact which is encoded in a set of Ward identities among the correlators of the energy-momentum tensor. The latter have interesting applications in lattice field theory: they offer novel ways to compute thermodynamic potentials, and a set of identities to renormalize non-perturbatively the energy-momentum tensor. At fixed bare parameters the shifted boundary conditions also provide a simple method to vary the temperature in much smaller steps than with the standard procedur...

Giusti, Leonardo

2013-01-01T23:59:59.000Z

326

Improving perturbation theory with cactus diagrams  

E-Print Network (OSTI)

We study a systematic improvement of perturbation theory for gauge fields on the lattice [hep-lat/0606001]; the improvement entails resumming, to all orders in the coupling constant, a dominant subclass of tadpole diagrams. This method, originally proposed for the Wilson gluon action, is extended here to encompass all possible gluon actions made of closed Wilson loops; any fermion action can be employed as well. The effect of resummation is to replace various parameters in the action (coupling constant, Symanzik and clover coefficient) by ``dressed'' values; the latter are solutions to certain coupled integral equations, which are easy to solve numerically. Some positive features of this method are: a) It is gauge invariant, b) it can be systematically applied to improve (to all orders) results obtained at any given order in perturbation theory, c) it does indeed absorb in the dressed parameters the bulk of tadpole contributions. Two different applications are presented: The additive renormalization of fermion masses, and the multiplicative renormalization Z_V (Z_A) of the vector (axial) current. In many cases where non-perturbative estimates of renormalization functions are also available for comparison, the agreement with improved perturbative results is consistently better as compared to results from bare perturbation theory.

Martha Constantinou; Haralambos Panagopoulos; Apostolos Skouroupathis

2006-12-04T23:59:59.000Z

327

Improved Perturbation Theory for Improved Lattice Actions  

E-Print Network (OSTI)

We study a systematic improvement of perturbation theory for gauge fields on the lattice; the improvement entails resumming, to all orders in the coupling constant, a dominant subclass of tadpole diagrams. This method, originally proposed for the Wilson gluon action, is extended here to encompass all possible gluon actions made of closed Wilson loops; any fermion action can be employed as well. The effect of resummation is to replace various parameters in the action (coupling constant, Symanzik coefficients, clover coefficient) by ``dressed'' values; the latter are solutions to certain coupled integral equations, which are easy to solve numerically. Some positive features of this method are: a) It is gauge invariant, b) it can be systematically applied to improve (to all orders) results obtained at any given order in perturbation theory, c) it does indeed absorb in the dressed parameters the bulk of tadpole contributions. Two different applications are presented: The additive renormalization of fermion masses, and the multiplicative renormalization Z_V (Z_A) of the vector (axial) current. In many cases where non-perturbative estimates of renormalization functions are also available for comparison, the agreement with improved perturbative results is significantly better as compared to results from bare perturbation theory.

M. Constantinou; H. Panagopoulos; A. Skouroupathis

2006-05-31T23:59:59.000Z

328

Stretched hydrogen molecule from a constrained-search density-functional perspective  

SciTech Connect

Constrained-search density functional theory gives valuable insights into the fundamentals of density functional theory. It provides exact results and bounds on the ground- and excited-state density functionals. An important advantage of the theory is that it gives guidance in the construction of functionals. Here they engage constrained search theory to explore issues associated with the functional behavior of 'stretched bonds' in molecular hydrogen. A constrained search is performed with familiar valence bond wavefunctions ordinarily used to describe molecular hydrogen. The effective, one-electron hamiltonian is computed and compared to the corresponding uncorrelated, Hartree-Fock effective hamiltonian. Analysis of the functional suggests the need to construct different functionals for the same density and to allow a competition among these functions. As a result the correlation energy functional is composed explicitly of energy gaps from the different functionals.

Valone, Steven M [Los Alamos National Laboratory; Levy, Mel [DIKE UNIV.

2009-01-01T23:59:59.000Z

329

Geometrical Methods in Gauge Theory  

E-Print Network (OSTI)

In this work we explore the geometrical interpretation of gauge theories through the formalism of fiber bundles. Moreover, we conduct an investigation in the topology of fiber bundles, providing a proof of the Classification Theorem. In the last chapter we present some applications, such as electromagnetism and generalized Kaluza-Klein Theory.

Henrique de A. Gomes

2006-10-25T23:59:59.000Z

330

A Simple Theory for Waterspouts  

Science Conference Proceedings (OSTI)

It is shown that the simple thermodynamic theory for dust devils, proposed by Rennó et al., also applies to waterspouts. The theory is based on the thermodynamics of heat engines and predicts the central pressure and the wind speed of these ...

Nilton O. Rennó; Howard B. Bluestein

2001-04-01T23:59:59.000Z

331

Theory of market fluctuations  

E-Print Network (OSTI)

We propose coalescent mechanism of firms growing, driving by the supply and redistribution of external resources. We show, that it leads to Zipf distribution of firms over their sizes, which turns to stretched exponent because of size-dependent effects. We also present new approach to describe fluctuations in the market, based on separation of hot (short-time) and cold (long-time) degrees of freedoms. It predicts observable tent-like distribution of firm grow rates with the same exponent of the power tail for different time scales. The theory explains observable grow and decrease asymmetry of the distribution, and its dependence on firm size. We also calculate the uni- and bivariate probability distributions of price fluctuations in financial market. The model takes into account feedback between price expectations and the real price, and explains first time all the set of empirical data for all groups of stocks: "compass rose" and "market mill" patterns, conditional distribution, "D-smile", z-shaped response,...

Panyukov, S V

2008-01-01T23:59:59.000Z

332

Discrete variable theory of triatomic photodissociation  

SciTech Connect

The coupled equations describing the photodissociation process are expressed in the discrete variable representation (DVR) in which the coupled equations are labeled by quadrature points rather than by internal basis functions. A large reduction in the dimensionality of the coupled equations can be realized since the spatially localized bound state nuclear wave function vanishes at most of the quadrature points, making only certain orientations of the fragments important in the region of strong interaction (small separation). The discrete variable theory of photodissociation is applied to the model dissociation of bent HCN in which the CN fragment is treated as a rigid rotor. The truncated DVR rotational distributions are compared with the exact close coupled rotational distributions, and excellent agreement with greatly reduced dimensionality of the equations is found.

Heather, R.W.; Light, J.C.

1983-07-01T23:59:59.000Z

333

Matrix models and stochastic growth in Donaldson-Thomas theory  

SciTech Connect

We show that the partition functions which enumerate Donaldson-Thomas invariants of local toric Calabi-Yau threefolds without compact divisors can be expressed in terms of specializations of the Schur measure. We also discuss the relevance of the Hall-Littlewood and Jack measures in the context of BPS state counting and study the partition functions at arbitrary points of the Kaehler moduli space. This rewriting in terms of symmetric functions leads to a unitary one-matrix model representation for Donaldson-Thomas theory. We describe explicitly how this result is related to the unitary matrix model description of Chern-Simons gauge theory. This representation is used to show that the generating functions for Donaldson-Thomas invariants are related to tau-functions of the integrable Toda and Toeplitz lattice hierarchies. The matrix model also leads to an interpretation of Donaldson-Thomas theory in terms of non-intersecting paths in the lock-step model of vicious walkers. We further show that these generating functions can be interpreted as normalization constants of a corner growth/last-passage stochastic model.

Szabo, Richard J. [Department of Mathematics, Heriot-Watt University, Colin Maclaurin Building, Riccarton, Edinburgh EH14 4AS, United Kingdom and Maxwell Institute for Mathematical Sciences, Edinburgh (United Kingdom); Tierz, Miguel [Grupo de Fisica Matematica, Complexo Interdisciplinar da Universidade de Lisboa, Av. Prof. Gama Pinto, 2, PT-1649-003 Lisboa (Portugal); Departamento de Analisis Matematico, Facultad de Ciencias Matematicas, Universidad Complutense de Madrid, Plaza de Ciencias 3, 28040 Madrid (Spain)

2012-10-15T23:59:59.000Z

334

Evaluating transport coefficients in real time thermal field theory  

E-Print Network (OSTI)

Transport coefficients in a hadronic gas have been calculated earlier in the imaginary time formulation of thermal field theory. The steps involved are to relate the defining retarded correlation function to the corresponding time-ordered one and to evaluate the latter in the conventional perturbation expansion. Here we carry out both the steps in the real time formulation.

S. Mallik; Sourav Sarkar

2012-11-12T23:59:59.000Z

335

Duality Invariance: From M-theory to Double Field Theory  

E-Print Network (OSTI)

We show how the duality invariant approach to M-theory formulated by Berman and Perry relates to the double field theory proposed by Hull and Zwiebach. In doing so we provide suggestions as to how Ramond fields can be incorporated into the double field theory. We find that the standard dimensional reduction procedure has a duality invariant (doubled) analogue in which the gauge fields of the doubled Kaluza-Klein ansatz encode the Ramond potentials. We identify the internal gauge index of these gauge fields with a spinorial index of O(d,d).

Daniel C. Thompson

2011-06-20T23:59:59.000Z

336

Finite size effect on the magnon's correlation functions  

Science Conference Proceedings (OSTI)

We calculate the finite size correction on the three-point correlation function between two giant magnons and one marginal operator, which is dual to a dilaton field of the bulk gravity theory. We also check that the structure constant in the string setup is exactly the same as one of the renormalization group analyses in the gauge theory.

Lee, Bum-Hoon [Center for Quantum Spacetime (CQUeST), Sogang University, Seoul 121-742 (Korea, Republic of); Department of Physics, Sogang University, Seoul 121-742 (Korea, Republic of); Park, Chanyong [Center for Quantum Spacetime (CQUeST), Sogang University, Seoul 121-742 (Korea, Republic of)

2011-10-15T23:59:59.000Z

337

Computing with almost periodic functions  

E-Print Network (OSTI)

The paper develops a method for discrete computational Fourier analysis of functions defined on quasicrystals and other almost periodic sets. A key point is to build the analysis around the emerging theory of quasicrystals and diffraction in the setting on local hulls and dynamical systems. Numerically computed approximations arising in this way are built out of the Fourier module of the quasicrystal in question, and approximate their target functions uniformly on the entire infinite space. The methods are entirely group theoretical, being based on finite groups and their duals, and they are practical and computable. Examples of functions based on the standard Fibonacci quasicrystal serve to illustrate the method (which is applicable to all quasicrystals modeled on the cut and project formalism).

R. V. Moody; M. Nesterenko; J. Patera

2008-08-13T23:59:59.000Z

338

Probabilistic Quantitative Precipitation Forecasts Based on Reforecast Analogs: Theory and Application  

Science Conference Proceedings (OSTI)

A general theory is proposed for the statistical correction of weather forecasts based on observed analogs. An estimate is sought for the probability density function (pdf) of the observed state, given today’s numerical forecast. Assume that an ...

Thomas M. Hamill; Jeffrey S. Whitaker

2006-11-01T23:59:59.000Z

339

A Reevaluation of Two Dispersion Theories  

Science Conference Proceedings (OSTI)

Three of the atmospheric datasets that were originally used to verity statistical dispersion theory are reevaluated. These datasets are described as well by transilient turbulence theory as by statistical theory over the range of time periods of ...

Roland Stull

1988-07-01T23:59:59.000Z

340

THE SOGGY SADDLE THEORY OF FISSION  

E-Print Network (OSTI)

SOGGY SADDLE THEORY OF FISSION L.G. Moretto and G. GuarinoMIWW The soggy saddle theory of fission L.6. Moretto and G.transition state theory of fission is generalized to allow

Moretto, L.G.

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "functional theory dft" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

String field theory and tachyon condensation  

E-Print Network (OSTI)

In this thesis I discuss various aspects of Witten's cubic string field theory. After a brief review of the basics of string field theory we begin by showing how string field theory can be used to check certain conjectures ...

Ellwood, Ian Thomas, 1977-

2004-01-01T23:59:59.000Z

342

Quantum proof systems and entanglement theory  

E-Print Network (OSTI)

Quantum complexity theory is important from the point of view of not only theory of computation but also quantum information theory. In particular, quantum multi-prover interactive proof systems are defined based on ...

Abolfathe Beikidezfuli, Salman

2009-01-01T23:59:59.000Z

343

Argonne CNM: Theory and Modeling Research  

NLE Websites -- All DOE Office Websites (Extended Search)

Theory and Modeling Group Leader: Stephen Gray An exciting aspect of nanoscience is the close interplay between theory and experiment. In the Theory and Modeling Group, we focus on...

344

Unstable Baroclinic Waves beyond Quasigeostrophic Theory  

Science Conference Proceedings (OSTI)

Quasigeostrophic theory is an approximation of the primitive equations in which the dynamics of geostrophically balanced motions are described by the advection of potential vorticity. Quasigeostrophic theory also represents a leading-order theory ...

Richard Rotunno; David J. Muraki; Chris Snyder

2000-10-01T23:59:59.000Z

345

Fusion Categories and Homotopy Theory  

E-Print Network (OSTI)

We apply the yoga of classical homotopy theory to classification problems of G-extensions of fusion and braided fusion categories, where G is a finite group. Namely, we reduce such problems to classification (up to homotopy) ...

Etingof, Pavel I.

346

STATISTICAL MECHANICS AND FIELD THEORY  

E-Print Network (OSTI)

1. L. 1. Schiff, Quantum Mechanics, third edition (McGraw-two-dimensional quantum mechanics problem vith a potential,Theory Methods to Statistical Mechanics Chapter I The Use of

Samuel, S.A.

2010-01-01T23:59:59.000Z

347

Legendre-Transformable Semigeostrophic Theories  

Science Conference Proceedings (OSTI)

For semigeostrophic (SG) theories derived from the Hamiltonian principles suggested by Salmon it is known that a duality exists between the physical coordinates and geopotential, on the one hand, and isentropic geostrophic momentum coordinates ...

R. J. Purser

1999-08-01T23:59:59.000Z

348

Social impact theory based optimizer  

Science Conference Proceedings (OSTI)

This paper introduces a novel stochastic and population-based binary optimization method inspired by social psychology. It is called Social Impact Theory based Optimization (SITO). The method has been developed with the use of some simple modifications ...

Martin Macaš; Lenka Lhotská

2007-09-01T23:59:59.000Z

349

Segmental alternations and metrical theory  

E-Print Network (OSTI)

This dissertation focuses on phonological alternations that are influenced or constrained by word-internal prosody, i.e. prominence and foot structure, and what these alternations can tell us about metrical theory. Detailed ...

Vaysman, Olga

2009-01-01T23:59:59.000Z

350

Chiral Gauge Theory for Graphene  

E-Print Network (OSTI)

We construct a chiral gauge theory to describe fractionalization of fermions in graphene. Thereby we extend a recently proposed model, which relies on vortex formation. Our chiral gauge fields provide dynamics for the vortices and also couple to the fermions.

R. Jackiw; S. -Y. Pi

2007-01-30T23:59:59.000Z

351

Argonne Physics Division - Theory Group  

NLE Websites -- All DOE Office Websites (Extended Search)

Theory Seminar Schedule Seminars are usually held in room B-221 of the Physics Building (203) at 3:00 pm. Click on a title to read an abstract, if available (underlined). Aroow...

352

Argonne Physics Division - Theory Group  

NLE Websites -- All DOE Office Websites (Extended Search)

XXVI Midwest Theory Get-Together, 6 & 7 September 2013. This XXVIth meeting in the series is being organised by Wayne Polyzou, polyzou@uiowa.edu from the University of Iowa, Iowa...

353

Microsoft Word - FEL theory  

NLE Websites -- All DOE Office Websites (Extended Search)

INTEGRAL EQUATION FOR A HIGH GAIN FEL N. A. Vinokurov * Introduction The theory of a high gain free electron laser (FEL) is now well developed (e.g., see 1). In this paper I...

354

Information Theory and Climate Prediction  

Science Conference Proceedings (OSTI)

This paper introduces the use of information theory in characterizing climate predictability. Specifically, the concepts of entropy and transinformation are employed. Entropy measures the amount of uncertainty in our knowledge of the state of the ...

Lai-Yung Leung; Gerald R. North

1990-01-01T23:59:59.000Z

355

Das Standard Modell als Theorie  

NLE Websites -- All DOE Office Websites (Extended Search)

as a Theory as a Theory Ungelöste Rätsel Das Standard Modell als Theorie Auch wenn das Standard Modell die im Experiment beobachteten Phänomene sehr gut beschreibt, so ist es dennoch eine unvollständige Theorie. Das Problem liegt darin, dass das Standard Modell nicht erklären kann, warum einige Teilchen gerade diejenigen Eigenschaften haben, die wir beobachten. Zum Beispiel, auch wenn den Physikern die Massen aller Quarks - mit Ausnahme derjenigen des top Quarks - seit Jahren bekannt waren, so war es dennoch nicht möglich die Masse des top Quarks ohne die Hilfe experimenteller Daten genau vorherzusagen. Das ist deshalb so, weil das Standard Modell keine Erklärung dafür geben kann, warum die Liste der Teilchenmassen gerade diese Zahlenwerte aufweist.

356

Multi-Determinant Wave-functions in Quantum Monte Carlo  

Science Conference Proceedings (OSTI)

Quantum Monte Carlo methods have received considerable attention over the last decades due to the great promise they have for the direct solution to the many-body Schrodinger equation for electronic systems. Thanks to a low scaling with number of particles, they present one of the best alternatives in the accurate study of large systems and solid state calculations. In spite of such promise, the method has not become popular in the quantum chemistry community, mainly due to the lack of control over the fixed-node error which can be large in many cases. In this article we present the application of large multi-determinant expansions in quantum Monte Carlo, studying its performance with first row dimers and the 55 molecules of the G1 test set. We demonstrate the potential of the wave-function to systematically reduce the fixed-node error in the calculations, achieving chemical accuracy in almost all cases studied. When compared to traditional methods in quantum chemistry, the results show a marked improvement over most methods including MP2, CCSD(T) and DFT with various functionals; in fact the only method able to produce better results is the explicitly-correlated CCSD(T) method with a large basis set. With recent developments in trial wave functions and algorithmic improvements in Quantum Monte Carlo, we are quickly approaching a time where the method can become the standard in the study of large molecular systems and solids.

Morales, Miguel A [Lawrence Livermore National Laboratory (LLNL); Mcminis, Jeremy [University of Illinois, Urbana-Champaign; Clark, Bryan K. [Princeton University; Kim, Jeongnim [ORNL; Scuseria, Gustavo E [Rice University

2012-01-01T23:59:59.000Z

357

Spectroscopic properties of photosynthetic reaction centers. 1. Theory  

Science Conference Proceedings (OSTI)

This paper is an attempt to address some of the key questions about the photosynthetic reaction center without simply adjusting a set of parameters to reproduce the relevant observables. Since perfect wave functions cannot be obtained at present by any model, they scale the wave functions of the individual monomers to fit their observed spectroscopic properties and then use these wave functions to calculate the properties of the oligomeric system. Such an approach avoids introducing any bias toward the properties of the oligomer. The theory is described in general terms in the present paper, and it is applied to Rps. viridis reaction centers in the following paper.

Warshel, A.; Parson, W.W.

1987-09-30T23:59:59.000Z

358

Supercritical N = 2 string theory  

E-Print Network (OSTI)

The N=2 string is examined in dimensions above the critical dimension (D=4) in a linear dilaton background. We demonstrate that string states in this background propagate in a single physical time dimension, as opposed to two such dimensions present when the dilaton gradient vanishes in D=4. We also find exact solutions describing dynamical dimensional reduction and transitions from N=2 string theory to bosonic string theory via closed-string tachyon condensation.

Hellerman, Simeon

2007-01-01T23:59:59.000Z

359

Rotating black strings in $f(R)$-Maxwell theory  

E-Print Network (OSTI)

In general, the field equations of $f(R)$ theory coupled to a matter field are very complicated and hence it is not easy to find exact analytical solutions. However, if one considers traceless energy-momentum tensor for the matter source as well as constant scalar curvature, one can derive some exact analytical solutions from $f(R)$ theory coupled to a matter field. In this paper, by assuming constant curvature scalar, we construct a class of charged rotating black string solutions in $f(R)$-Maxwell theory. We study the physical properties and obtain the conserved quantities of the solutions. The conserved and thermodynamic quantities computed here depend on function $f'(R_{0})$ and differ completely from those of Einstein theory in AdS spaces. Besides, unlike Einstein gravity, the entropy does not obey the area law. We also investigate the validity of the first law of thermodynamics as well as the stability analysis in the canonical ensemble, and show that the black string solutions are always thermodynamically stable in $f(R)$-Maxwell theory with constant curvature scalar. Finally, we extend the study to the case where the Ricci scalar is not a constant and in particular $R=R(r)$. In this case, by using the Lagrangian multipliers method, we derive an analytical black string solution from $f(R)$ gravity and reconstructed the function $R(r)$. We find that this class of solutions has an additional logaritmic term in the metric function which incorporates the effect of the $f(R)$ theory in the solutions.

S. Salarpour; A. Sheykhi; Y. Bahrampour

2013-04-10T23:59:59.000Z

360

Corrections to gauge theories in effective quantum gravity with a cutoff  

E-Print Network (OSTI)

We calculate the lowest order quantum gravity contributions to QED beta function in an effective field theory picture with a momentum cutoff. We use a recently proposed 4 dimensional improved momentum cutoff that preserves gauge and Lorentz symmetries. We find that there is non-vanishing quadratic contribution to the photon 2-point function but that does not lead to the running of the original coupling after renormalization. We argue that gravity cannot turn gauge theories asymptotically free.

G. Cynolter; E. Lendvai

2013-07-17T23:59:59.000Z

Note: This page contains sample records for the topic "functional theory dft" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Theory, Modeling & Simulation | More Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Theory, Modeling and Simulation SHARE Theory, Modeling and Simulation ORNL conducts a broad range of theoretical research in the physical sciences with over 60 staff members and...

362

Theory, Modeling & Simulation | More Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Materials Theory and Simulation SHARE Materials Theory and Simulation ORNL conducts a broad range of theoretical research in the physical sciences with over 60 staff members and...

363

MSD Condensed Matter Theory - Argonne National Laboratories,...  

NLE Websites -- All DOE Office Websites (Extended Search)

Home Condensed Matter Theory Condensed Matter Theory research interacts with the materials research program at ANL through a mix of individual theoretical studies and...

364

Nonlinear forecasting and iterated function systems  

Science Conference Proceedings (OSTI)

The theory of dynamical forecasting can be extended to iterated function systems. An unordered set of iterates may be sufficient to construct a simulation of the unknown dynamics. The underlying dynamical system may be nondeterministic: A random element may be allowed in the dynamics

Giorgio Mantica; B. G. Giraud

1992-01-01T23:59:59.000Z

365

Classification with dynamic reducts and belief functions  

Science Conference Proceedings (OSTI)

In this paper, we propose two approaches of classification namely, Dynamic Belief Rough Set Classifier (D-BRSC) and Dynamic Belief Rough Set Classifier based on Generalization Distribution Table (D-BRSC-GDT). Both the classifiers are induced from uncertain ... Keywords: belief function theory, classification, dynamic reduct, generalization distribution table, rough sets, uncertainty

Salsabil Trabelsi; Zied Elouedi; Pawan Lingras

2011-01-01T23:59:59.000Z

366

Parity violating quantum kinetic theory in (2+1)-dimensions  

E-Print Network (OSTI)

We study the kinetic theory for a (2+1)-dimensional fermionic system with special emphasis on the parity violating properties associated with the fermion mass. The Wigner function approach is used to derive hydrodynamical transport coefficients to the first spatial derivative order. As a first attempt, the collisions between fermions are neglected. The resulting system is dissipationless. The parity violating Hall electric conductivity has the same temperature and chemical potential dependence as the quantum field theory result at one-loop. Vorticity dependent transport properties, which were not considered before, also emerge naturally in this approach.

Jiunn-Wei Chen; Jian-Hua Gao; Juan Liu; Shi Pu; Qun Wang

2013-05-08T23:59:59.000Z

367

Loop Quantum Theory Applied to Biology and Nonlinear Whole Biology  

E-Print Network (OSTI)

The loop quantum theory, which constitutes a very small discontinuous space, as new method is applied to biology. The model of protein folding and lungs is proposed. In the model, some known results are used, and four approximate conclusions are obtained: their structures are quantized, their space regions are finite, various singularities correspond to folding and crossed points, and different types of catastrophe exist. Further, based on the inseparability and correlativity of the biological systems, the nonlinear whole biology is proposed, and four basic hypotheses are formed. It may unify reductionism and holism, structuralism and functionalism. Finally, the medical meaning of the theory is discussed briefly.

Yi-Fang Chang

2008-01-02T23:59:59.000Z

368

Sheldon Glashow, the Electroweak Theory, and the Grand Unified Theory  

Office of Scientific and Technical Information (OSTI)

Sheldon Glashow and the Electroweak Theory Sheldon Glashow and the Electroweak Theory Resources with Additional Information Sheldon Glashow Courtesy AIP Emilio Segrè Visual Archives, Segrè Collection [Sheldon] 'Glashow shared the 1979 Nobel Prize for physics with Steven Weinberg and Abdus Salam for unifying the theories of weak and electromagnetic forces. The new "electroweak" theory underlies all of particle physics and provides a framework for understanding how the early universe evolved and how the chemical elements were created. ... "Glashow's work has been instrumental in our understanding of how our universe came into being," says Lawrence R. Sulak, chairman of the Boston University physics department. "In the years since winning the prize, Glashow has helped develop the Grand Unified Theory of all particles and all forces. Its predictions led to the construction of massive underground detectors, the refinement of the unification models, the first observation of neutrinos from a supernova, and the recent discovery that neutrinos have mass. Glashow has fueled an ongoing search for rare events and exotic effects that may shed further light on the evolution of the early universe."1

369

Essays in game theory and institutions  

E-Print Network (OSTI)

This dissertation is a compilation of essays highlighting the usefulness of game theory in understanding socio-economic phenomena. The second chapter tries to provide a reason for the strict codes of conduct that have been imposed on unmarried girls in almost every society at some point of time in its history using tools from classical game theory. If men prefer to marry submissive women, then parents of girls will have an incentive to signal the submissiveness of their daughters in various ways in order to attract better matches. At the same time, parents will find it costlier to signal the submissiveness of girls who are not really submissive. This line of reasoning thus helps us interpret phenomena such as veiling, footbinding, and sequestration of women in general as signals of submissiveness. The third chapter attempts to rationalize some of the ad hoc rules proposed for dividing a bankrupt estate using tools from evolutionary game theory. The ad hoc rules differ from each other because of the axioms that are imposed in addition to efficiency and claims boundedness. Efficiency requires that the estate be completely divided between the claimants, and claims boundedness requires that no claimant be awarded more than her initial contribution. This dissertation tries to show that an ad hoc rule can be rationalized as the unique self-enforcing long run outcome of Young's [46] evolutionary bargaining model by using certain intuitive rules for the Nash demand game. In the fourth chapter I present a simple model of conflict over inputs in an economy with ill-defined property rights. Agents produce output from the land they hold, which in turn can be allocated to consumption or the production of guns. There is no agency to enforce rights over the initial land holdings, and the future holdings of land are determined using a contest success function that depends on the guns produced by both agents. I characterize the equilibria in which only one, both, and none of the agents produce guns, as a function of the total land and the inequality of initial land holdings for general forms of utility, production, cost, and contest success functions.

Rai, Birendra Kumar

2006-08-01T23:59:59.000Z

370

Operator theory of electrical resistance networks  

E-Print Network (OSTI)

A resistance network is a weighted graph $(G,c)$ with intrinsic (resistance) metric $R$. We embed the resistance network into the Hilbert space ${\\mathcal H}_{\\mathcal E}$ of functions of finite energy. We use the resistance metric to study ${\\mathcal H}_{\\mathcal E}$, and vice versa and show that the embedded images of the vertices $\\{v_x\\}$ form a reproducing kernel for this Hilbert space. We also obtain a discrete version of the Gauss-Green formula for resistance networks and show that resistance networks which support nonconstant harmonic functions of finite energy have a certain type of \\emph{boundary}. We obtain an analytic boundary representation for the harmonic functions of finite energy in a sense analogous to the Poisson or Martin boundary representations, but with different hypotheses, and for a different class of functions. In the process, we construct a dense space of "smooth" functions of finite energy and obtain a Gel'fand triple for ${\\mathcal H}_{\\mathcal E}$. This allows us to represent the resistance network as a system of Gaussian random variables indexed by vertices. We also study the spectral representation for $\\Delta$ on ${\\mathcal H}_{\\mathcal E}$ and show how nonzero defect entails a nontrivial boundary. All of the above are are detected by the operator theory of ${\\mathcal H}_{\\mathcal E}$ but not $\\ell^2$. Our results apply to the Heisenberg model for the isotropic ferromagnet, improving earlier results of R. T. Powers on the problem of long-range order (in reference to KMS states on the $C^\\ast$-algebra of the model).

Palle E. T. Jorgensen; Erin P. J. Pearse

2008-06-23T23:59:59.000Z

371

On triviality of $\\lambda\\phi^4$ quantum field theory in four dimensions  

E-Print Network (OSTI)

Interacting quantum scalar field theories in $dS_D\\times M_d$ spacetime can be reduced to Euclidean field theories in $M_d$ space in the vicinity of $I_+$ infinity of $dS_D$ spacetime. Using this non-perturbative mapping, we analyze the critical behavior of Euclidean $\\lambda\\phi_4^4$ theory in the symmetric phase and find the asymptotic behavior $\\beta(\\lambda)\\sim \\lambda$ of the beta function at strong coupling. Scaling violating contributions to the beta function are also estimated in this regime.

Podolsky, Dmitry I

2010-01-01T23:59:59.000Z

372

Lectures on 2d Gauge Theories: Topological Aspects and Path Integral Techniques  

E-Print Network (OSTI)

These are lecture notes of lectures presented at the 1993 Trieste Summer School, dealing with two classes of two-dimensional field theories, (topological) Yang-Mills theory and the G/G gauged WZW model. The aim of these lectures is to exhibit and extract the topological information contained in these theories, and to present a technique (a Weyl integral formula for path integrals) which allows one to calculate directly their partition function and topological correlation functions on arbitrary closed surfaces. Topics dealt with are (among others): solution of Yang-Mills theory on arbitrary surfaces; calculation of intersection numbers of moduli spaces of flat connections; coupling of Yang-Mills theory to coadjoint orbits and intersection numbers of moduli spaces of parabolic bundles; derivation of the Verlinde formula from the G/G model; derivation of the shift k to k+h in the G/G model via the index of the twisted Dolbeault complex.

Matthias Blau; George Thompson

1993-10-21T23:59:59.000Z

373

Towards a Theory of Networked Computation  

E-Print Network (OSTI)

The increasing prominence of the Internet, the Web, and large data networks in general has profoundly affected social and commercial activity. It has also wrought one of the most profound changes in Computer Science since its inception. Traditionally, Computer-Science research has focused primarily on understanding how best to design, build, analyze, and program computers. The research agenda has now expanded to include the question of how best to design, build, analyze, and operate networks. How can one ensure that a network created and used by many autonomous organizations and individuals functions properly, respects the rights of users, and exploits its vast shared resources fully and fairly? The Theory of Computation (ToC) community can help address the full spectrum of research questions implicit in this grand challenge by developing a Theory of Networked Computation (ToNC), encompassing both positive and negative results. ToC research has already evolved with and influenced the growth of the Web, producing interesting results and techniques in diverse problem domains, including search and information retrieval, network protocols, error correction, Internet-based auctions, and security.

Joan Feigenbaum; Michael Mitzenmacher

2009-01-01T23:59:59.000Z

374

Resilience: Theory and Application.  

SciTech Connect

There is strong agreement among policymakers, practitioners, and academic researchers that the concept of resilience must play a major role in assessing the extent to which various entities - critical infrastructure owners and operators, communities, regions, and the Nation - are prepared to respond to and recover from the full range of threats they face. Despite this agreement, consensus regarding important issues, such as how resilience should be defined, assessed, and measured, is lacking. The analysis presented here is part of a broader research effort to develop and implement assessments of resilience at the asset/facility and community/regional levels. The literature contains various definitions of resilience. Some studies have defined resilience as the ability of an entity to recover, or 'bounce back,' from the adverse effects of a natural or manmade threat. Such a definition assumes that actions taken prior to the occurrence of an adverse event - actions typically associated with resistance and anticipation - are not properly included as determinants of resilience. Other analyses, in contrast, include one or more of these actions in their definitions. To accommodate these different definitions, we recognize a subset of resistance- and anticipation-related actions that are taken based on the assumption that an adverse event is going to occur. Such actions are in the domain of resilience because they reduce both the immediate and longer-term adverse consequences that result from an adverse event. Recognizing resistance- and anticipation-related actions that take the adverse event as a given accommodates the set of resilience-related actions in a clear-cut manner. With these considerations in mind, resilience can be defined as: 'the ability of an entity - e.g., asset, organization, community, region - to anticipate, resist, absorb, respond to, adapt to, and recover from a disturbance.' Because critical infrastructure resilience is important both in its own right and because of its implications for community/regional resilience, it is especially important to develop a sound methodology for assessing resilience at the asset/facility level. This objective will be accomplished by collecting data on four broadly defined groups of resilience-enhancing measures: preparedness, mitigation measures, response capabilities, and recovery mechanisms. Table ES-1 illustrates how the six components that define resilience are connected to the actions that enhance the capacity of an entity to be resilient. The relationships illustrated in Table ES-1 provide the framework for developing a survey instrument that will be used to elicit the information required to assess resilience at the asset/facility level. The resilience of a community/region is a function of the resilience of its subsystems, including its critical infrastructures, economy, civil society, governance (including emergency services), and supply chains/dependencies. The number and complexity of these subsystems will make the measurement of resilience more challenging as we move from individual assets/facilities to the community/regional level (where critical infrastructure resilience is only one component). Specific challenges include uncertainty about relationships (e.g., the composition of specific supply chains), data gaps, and time and budget constraints that prevent collection of all of the information needed to construct a comprehensive assessment of the resilience of a specific community or region. These challenges can be addressed, at least partially, by adopting a 'systems approach' to the assessment of resilience. In a systems approach, the extent to which the analysis addresses the resilience of the individual subsystems can vary. Specifically, high-level systems analysis can be used to identify the most important lower-level systems. In turn, within the most important lower-level systems, site assessment data should be collected only on the most critical asset-level components about which the least is known. Implementation of the strategies outlined here to as

Carlson, J.L.; Haffenden, R.A.; Bassett, G.W.; Buehring, W.A.; Collins, M.J., III; Folga, S.M.; Petit, F.D.; Phillips, J.A.; Verner, D.R.; Whitfield, R.G. (Decision and Information Sciences)

2012-02-03T23:59:59.000Z

375

Scaling Theory and Numerical Simulations of Aerogel Sintering  

E-Print Network (OSTI)

A simple scaling theory for the sintering of fractal aerogels is presented. The densification at small scales is described by an increase of the lower cut-off length a accompanied by a decrease of the upper cut-off length ?, in order to conserve the total mass of the system. Scaling laws are derived which predict how a, ? and the specific pore surface area ? should depend on the density ?. Following the general ideas of the theory, numerical simulations of sintering are proposed starting from computer simulations of aerogel structure based on a diffusion-limited cluster-cluster aggregation gelling process. The numerical results for a, ? and ? as a function of ? are discussed according to the initial aerogel density. The scaling theory is only fully recovered in the limit of very low density where the original values of a and ? are well separated. These numerical results are compared with experiments on partially densified aerogels.

Rémi Jullien; Nathalie Olivi-tran; Anwar Hasmy; Thierry Woignier; Daniel Bourret; Robert Sempéré

2008-01-01T23:59:59.000Z

376

Asymptotic Symmetries of Yang-Mills Theory  

E-Print Network (OSTI)

Asymptotic symmetries at future null infinity (I+) of Minkowski space for electrodynamics with massless charged fields, as well as non-Abelian gauge theories with gauge group G, are considered at the semiclassical level. The possibility of charge/color flux through I+ suggests the symmetry group is infinite-dimensional. It is conjectured that the symmetries include a G Kac-Moody symmetry whose generators are "large" gauge transformations which approach locally holomorphic functions on the conformal two-sphere at I+ and are invariant under null translations. The Kac-Moody currents are constructed from the gauge field at the future boundary of I+. The current Ward identities include Weinberg's soft photon theorem and its colored extension.

Andrew Strominger

2013-08-02T23:59:59.000Z

377

Comparative Study of Selected Wave Function and Density Functional Methods for Noncovalent Interaction Energy Calculations Using the Extended S22 Data Set  

Science Conference Proceedings (OSTI)

In this paper, an extension of the S22 data set of Jurecka et al. (Jure?ka, P.; Šponer, J.; ?erný, J.; Hobza, P. Phys. Chem. Chem. Phys. 2006, 8, 1985.), the data set of benchmark CCSD(T)/CBS interaction energies of twenty-two noncovalent complexes in equilibrium geometries, is presented. The S22 data set has been extended by including the stretched (one shortened and three elongated) complex geometries of the S22 data set along the main noncovalent interaction coordinate. The goal of this work is to assess the accuracy of the popular wave function methods (MP2-, MP3- and, CCSD-based) and density functional methods (with and without empirical correction for the dispersion energy) for noncovalent complexes based on a statistical evaluation not only in equilibrium, but also in nonequilibrium geometries. The results obtained in this work provide information on whether an accurate and balanced description of the different interaction types and complex geometry distortions can be expected from the tested methods. This information has an important implication in the calculation of large molecular complexes, where the number of distant interacting molecular fragments, often in far from equilibrium geometries, increases rapidly with the system size. The best performing WFT methods were found to be the SCS-CCSD (spin-component scaled CCSD, according to Takatani, T.; Hohenstein, E. G.; Sherrill, C. D. J. Chem. Phys. 2008, 128, 124111), MP2C (dispersion-corrected MP2, according to Hesselmann, A. J. Chem. Phys. 2008, 128, 144112), and MP2.5 (scaled MP3, according to Pito?ák, M.; Neogrády, P.; ?erný, J.; Grimme, S.; Hobza, P. ChemPhysChem 2009, 10, 282.). Since none of the DFT methods fulfilled the required statistical criteria proposed in this work, they cannot be generally recommended for large-scale calculations. The DFT methods still have the potential to deliver accurate results for large molecules, but most likely on the basis of an error cancellation.

Grafova, Lucie; Pitonak, Michal; Rezac, Jan; Hobza, Pavel

2010-08-10T23:59:59.000Z

378

Free Energy of ABJM Theory  

E-Print Network (OSTI)

The free energy of ABJM theory has previously been computed in the strong and weak coupling limits. In this note, we report on results for the computation of the first non-vanishing quantum correction to the free energy, from the field theory side. The correction can be expressed in terms of a thermal mass for the scalar fields. This mass vanishes to 1-loop order, but there is a non-vanishing result to 2-loop order. Hence, the leading correction to the free energy is non-analytic in the 't Hooft coupling constant lambda. The reason is that the infrared divergences necessitate a resummation of ring diagrams and a related reorganization of perturbation theory, in which already the leading correction receives contributions from all orders in lambda. These results suggest that the free energy interpolates smoothly between weak and strong coupling.

Mikael Smedbäck

2011-03-24T23:59:59.000Z

379

Lattice QCD and String Theory  

E-Print Network (OSTI)

Bosonic string formation in gauge theories is reviewed with particular attention to the confining flux in lattice QCD and its string theory description. Recent results on the Casimir energy of the ground state and the string excitation spectrum are analyzed in the Dirichlet string limit of large separation between static sources. The closed string-soliton (torelon) with electric flux winding around a compact dimension and the three-string with a Y-junction created by three static sources are also reviewed. It is shown that string spectra from lattice simulations are consistent with universal predictions of the leading operators from the derivative expansion of a Poincare invariant effective string Lagrangian with reparameterization symmetry. Important characterisitics of the confining flux, like stiffness and the related massive breather modes, are coded in operators with higher derivatives and their determination remains a difficult challenge for lattice gauge theory.

Julius Kuti

2005-11-08T23:59:59.000Z

380

Functional Materials for Energy | Advanced Materials | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Energy Storage Fuel Cells Thermoelectrics Separations Materials Catalysis Sensor Materials Polymers and Composites Carbon Fiber Related Research Chemistry and Physics at Interfaces Materials Synthesis from Atoms to Systems Materials Characterization Materials Theory and Simulation Energy Frontier Research Centers Advanced Materials Home | Science & Discovery | Advanced Materials | Research Areas | Functional Materials for Energy SHARE Functional Materials for Energy The concept of functional materials for energy occupies a very prominent position in ORNL's research and more broadly the scientific research sponsored by DOE's Basic Energy Sciences. These materials facilitate the capture and transformation of energy, the storage of energy or the efficient release and utilization of stored energy. A different kind of

Note: This page contains sample records for the topic "functional theory dft" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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381

Heavy ions and string theory  

E-Print Network (OSTI)

We review a selection of recent developments in the application of ideas of string theory to heavy ion physics. Our topics divide naturally into equilibrium and non-equilibrium phenomena. On the non-equilibrium side, we discuss generalizations of Bjorken flow, numerical simulations of black hole formation in asymptotically anti-de Sitter geometries, equilibration in the dual field theory, and hard probes. On the equilibrium side, we summarize improved holographic QCD, extraction of transport coefficients, inclusion of chemical potentials, and approaches to the phase diagram. We close with some possible directions for future research.

Oliver DeWolfe; Steven S. Gubser; Christopher Rosen; Derek Teaney

2013-04-29T23:59:59.000Z

382

Principles of Arrangement Field Theory  

E-Print Network (OSTI)

In this paper I attempt to summarize the fundamental principles which underlie to Arrangement Field Theory. In my intention the exposition would be the most possible intelligible and self-contained. However the exposed concepts are revisited in the light of the new researches, so that they could appear slightly different than in the previous works. Much emphasis is posed here to the power of theory to predict the number of fermionic families (flavours) and space-time dimensions. I also give a quick glance to the entanglement phenomenon and its interpretation as microscopic wormhole.

Diego Marin

2012-07-07T23:59:59.000Z

383

Degenerating behavior of Green's function  

E-Print Network (OSTI)

Let the unions of real intervals $I = \\cup_{j = 1}^l [a_{2 j -1},a_{2j}],$ $a_1 0.$ We show how to express asymptotically the Green's function $\\phi(z,\\infty,E \\cup I_n)$ of $E \\cup I_n$ at $z = \\infty$ in terms of the Green's function $\\phi(z,\\infty,E)$ and $\\phi(z,c_k,E).$ The formula yields immediately asymptotics for $\\phi^n(z,\\infty,E \\cup I_n)$ with respect to $n$ which are important in many problems of approximation theory. Another consequence is an asymptotic representation of $cap(E \\cup I_n)$ in terms of $cap(E)$ and $\\phi(z,c_k,E)$ and of the harmonic measure $\\omega(\\infty, E_j,E \\cup I_n).$

Peherstorfer, Franz

2010-01-01T23:59:59.000Z

384

BNL | Center for Functional Nanomaterials (CFN)  

NLE Websites -- All DOE Office Websites (Extended Search)

CFN People CFN People Center for Functional Nanomaterials An Office of Science User Facility Home Facilities Proximal Probes Nanofabrication Materials Synthesis and Characterization Theory and Computation Advanced UV and X-ray Probes Advanced Optical Spectroscopy and Microscopy Electron Microscopy Research Interface Science and Catalysis Soft and Bio Nanomaterials Electronic Nanomaterials Electron Microscopy Theory and Computation Working at CFN Arrival & Departure Reports & Publications Data Management The Guide to Brookhaven Safety Procedures Operations Plan COSA Training Hours of Operation Laser System Qualification Transport of Hazarous Materials Publications News CFN News Research Highlights iCFN, the CFN Newsletter Videos Events People Staff List Science Advisory Committee Users' Executive Committee

385

Functional Integration on Constrained Function Spaces  

E-Print Network (OSTI)

Analogy with Bayesian inference is used to study constrained physical systems within the context of functional integration. Since functional integrals probe function spaces, both kinematical and dynamical constraints are treated simultaneously and on equal footing. Following the analogy, functional counterparts of conditional and conjugate probability distributions are introduced for integrators and then applied to some well-known examples of constrained functional integrals. The analysis leads to some new functional integration tools and methods. These are utilized to construct a model of the prime counting function as a constrained gamma process.

J. LaChapelle

2012-12-03T23:59:59.000Z

386

Effective theory for deformed nuclei  

E-Print Network (OSTI)

Techniques from effective field theory are applied to nuclear rotation. This approach exploits the spontaneous breaking of rotational symmetry and the separation of scale between low-energy Nambu-Goldstone rotational modes and high-energy vibrational and nucleonic degrees of freedom. A power counting is established and the Hamiltonian is constructed at next-to-leading order.

Papenbrock, T

2010-01-01T23:59:59.000Z

387

"Chromatic" homotopy theory Haynes Miller  

E-Print Network (OSTI)

of large but finite dimension. Chro- matic homotopy theory is an organizing principle which is highly devel Hq+n(n K) = Hq(K) By functoriality, there are maps [K, L] [K, L] [2 K, 2 L] · · · and these maps

Miller, Haynes

388

Quantum Field Theory in Graphene  

E-Print Network (OSTI)

This is a short non-technical introduction to applications of the Quantum Field Theory methods to graphene. We derive the Dirac model from the tight binding model and describe calculations of the polarization operator (conductivity). Later on, we use this quantity to describe the Quantum Hall Effect, light absorption by graphene, the Faraday effect, and the Casimir interaction.

Fialkovsky, I V

2011-01-01T23:59:59.000Z

389

Quantum Field Theory in Graphene  

E-Print Network (OSTI)

This is a short non-technical introduction to applications of the Quantum Field Theory methods to graphene. We derive the Dirac model from the tight binding model and describe calculations of the polarization operator (conductivity). Later on, we use this quantity to describe the Quantum Hall Effect, light absorption by graphene, the Faraday effect, and the Casimir interaction.

I. V. Fialkovsky; D. V. Vassilevich

2011-11-13T23:59:59.000Z

390

Moriond Electroweak 2006: Theory summary  

SciTech Connect

A concise look at the big picture of particle physics, including the status of the Standard Model, neutrinos, supersymmetry, extra dimensions and cosmology. Based upon the theoretical summary presented at the XLIst Rencontres de Moriond on Electroweak Interactions and Unified Theories, La Thuile, 11-18 March 2006.

Lykken, Joseph D.; /Fermilab

2006-07-01T23:59:59.000Z

391

Computers for Lattice Field Theories  

E-Print Network (OSTI)

Parallel computers dedicated to lattice field theories are reviewed with emphasis on the three recent projects, the Teraflops project in the US, the CP-PACS project in Japan and the 0.5-Teraflops project in the US. Some new commercial parallel computers are also discussed. Recent development of semiconductor technologies is briefly surveyed in relation to possible approaches toward Teraflops computers.

Y. Iwasaki

1994-01-26T23:59:59.000Z

392

Present Status of the Theory of Fission of hot Nuclei  

E-Print Network (OSTI)

Recent progress in the theory of fission of hot nuclei is reported. We discuss in particular the properties of the friction formfactor as function of the deformation (and possibly of the temperature) which are necessary to reproduce data concerning fission of hot nuclei and its accompanying light particle and $\\gamma$-ray emission. Recent theoretical work gives support to a phenomenological friction form factor (proposed some time ago), which is weak for compact shapes and increases on the way to scission.

P. Fröbrich

2004-01-21T23:59:59.000Z

393

Scalar tensor theory : validity of Cosmic no hair conjecture  

E-Print Network (OSTI)

The paper deals with cosmic no hair conjecture in scalar tensor theory of gravity. Here we have considered both Jordan frame and Einstein frame to examine the conjecture. In Jordan frame, one should restrict both the coupling function of the scalar field and the coupling parameter in addition to the ususal energy conditions for the the matter field for the validity of CNHC while in Einstein frame the restrictions are purely on the energy conditions.

Sudeshna Mukerji; Nairwita Mazumder; Ritabrata Biswas; Subenoy Chakraborty

2011-06-09T23:59:59.000Z

394

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

E-Print Network (OSTI)

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

Lajos Diósi

2013-02-21T23:59:59.000Z

395

Education---Oriented Virtual Environment for Clothing Thermal Functional Performance  

Science Conference Proceedings (OSTI)

This paper presents a simulation environment for the education of clothing thermal function. It allows learners in a virtual environment to learn the clothing thermal comfort theory and identify the most important factors that influence clothing thermal ... Keywords: Visualization, clothing thermal functional performance, education oriented, virtual environment

Xiaonan Luo; Wenbang Hou; Yi Li

2007-05-01T23:59:59.000Z

396

Usage Of New Activation Function In Neuro-Symbolic Integration  

SciTech Connect

New activation function is examined for its ability to accelerate the performance of doing logic programming in Hopfield network. This method has a higher capacity and upgrades the neuro symbolic integration. Computer simulations are carried out to validate the effectiveness of the new activation function. Empirical results obtained support our theory.

Sathasivam, Saratha [School of Mathematical Sciences, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia)

2010-12-23T23:59:59.000Z

397

Nuclear Energy Density Functionals Constrained by Low-Energy QCD  

E-Print Network (OSTI)

A microscopic framework of nuclear energy density functionals is reviewed, which establishes a direct relation between low-energy QCD and nuclear structure, synthesizing effective field theory methods and principles of density functional theory. Guided by two closely related features of QCD in the low-energy limit: a) in-medium changes of vacuum condensates, and b) spontaneous breaking of chiral symmetry; a relativistic energy density functional is developed and applied in studies of ground-state properties of spherical and deformed nuclei.

Vretenar, Dario

2008-01-01T23:59:59.000Z

398

Nuclear Energy Density Functionals Constrained by Low-Energy QCD  

E-Print Network (OSTI)

A microscopic framework of nuclear energy density functionals is reviewed, which establishes a direct relation between low-energy QCD and nuclear structure, synthesizing effective field theory methods and principles of density functional theory. Guided by two closely related features of QCD in the low-energy limit: a) in-medium changes of vacuum condensates, and b) spontaneous breaking of chiral symmetry; a relativistic energy density functional is developed and applied in studies of ground-state properties of spherical and deformed nuclei.

Dario Vretenar

2008-02-06T23:59:59.000Z

399

Topics in Noncommutative Gauge Theories and Deformed Relativistic Theories  

E-Print Network (OSTI)

This is my PhD thesis. In this thesis we study the gauge theories on noncommutative Moyal space. We find new static solitons and instantons in terms of the so called generalized Bose operators. Generalized Bose operators are constructed to describe reducible representation of the oscillator algebra. They create/annihilate $k$-quanta, $k$ being a positive integer. We start with giving an alternative description to the already found static magnetic flux tube solutions of the noncommutative gauge theories in terms of generalized Bose operators. The Nielsen-Olesen vortex solutions found in terms of these operators reduce to the already found ones. On the contrary we find a class of new instaton solutions which are unitarily inequivalant to the the ones found from ADHM construction on noncommutative space. The charge of the instaton has a description in terms of the index representing the reducibility of the Fock space, i.e., $k$. After studying the static solitonic solutions in noncommutative Minkowski space and the instaton solutions in noncommutative Euclidean space we go on to study the implications of the time-space noncommutativity in Minkowski space. To understand it properly we study the time-dependent transitions of a forced harmonic oscillator in noncommutative 1+1 dimensional spacetime. We also try to understand the implications of the found results in the context of quantum optics. We then shift to the so called DSR theories which are related to a different kind of noncommutative ($\\kappa$-Minkowski) space. DSR (Doubly/Deformed Special Relativity) aims to search for an alternate relativistic theory which keeps a length/energy scale (the Planck scale) and a velocity scale (the speed of light scale) invariant. We study thermodynamics of an ideal gas in such a scenario.

Nitin Chandra

2013-01-17T23:59:59.000Z

400

Theory  

Science Conference Proceedings (OSTI)

Table 4   Line intensity...Identification (qualitative analyses) d-I search/match (PDF Hanawalt) Intensity changes with element substitution Crystal structure analysis Differences in fine grained state from single crystal state Structures of materials which only occur in fine grained state Quantitative analysis Phase...

Note: This page contains sample records for the topic "functional theory dft" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Diffeomorphisms in group field theories  

SciTech Connect

We study the issue of diffeomorphism symmetry in group field theories (GFT), using the noncommutative metric representation introduced by A. Baratin and D. Oriti [Phys. Rev. Lett. 105, 221302 (2010).]. In the colored Boulatov model for 3d gravity, we identify a field (quantum) symmetry which ties together the vertex translation invariance of discrete gravity, the flatness constraint of canonical quantum gravity, and the topological (coarse-graining) identities for the 6j symbols. We also show how, for the GFT graphs dual to manifolds, the invariance of the Feynman amplitudes encodes the discrete residual action of diffeomorphisms in simplicial gravity path integrals. We extend the results to GFT models for higher-dimensional BF theories and discuss various insights that they provide on the GFT formalism itself.

Baratin, Aristide [Triangle de la Physique, CPHT Ecole Polytechnique, IPhT Saclay, LPT Orsay and Laboratoire de Physique Theorique, CNRS UMR 8627, Universite Paris XI, F-91405 Orsay Cedex (France); Girelli, Florian [School of Physics, University of Sydney, Sydney, New South Wales 2006 (Australia); Oriti, Daniele [Max Planck Institute for Gravitational Physics, Albert Einstein Institute, Am Muehlenberg 1, 14467 Golm (Germany)

2011-05-15T23:59:59.000Z

402

Fundamental constants in effective theory  

E-Print Network (OSTI)

There is a discussion between L. B. Okun, G. Veneziano and M. J. Duff, concerning the number of fundamental dimensionful constants in physics [1]. They advocated correspondingly 3, 2 and 0 fundamental constants. Here we consider this problem on example of the effective relativistic quantum field theory, which emerges in the low energy corner of quantum liquids and which reproduces many features of our physics including chiral fermions, gauge fields and dynamical gravity. 1 Introduction. The effective relativistic quantum field theory (RQFT) arising as emergent phenomenon in quantum liquids [2], or in other condensed matter systems [3], allows us to look at the problem of fundamental constants from the outside, i.e. from the point of view of an external observer who does not

G. E. Volovik

2008-01-01T23:59:59.000Z

403

Theory of magnetoresistance in multilayers  

Science Conference Proceedings (OSTI)

Recently it has been found that metallic multilayer films exhibit novel phenomena, particularly giant magnetoresistance in Fe/Cr, Co/Cu, Co/Cu/NiFe/Cu, and other multilayers. In this review, the authors explicate the theory of the giant magnetoresistance effect, placing emphasis on its mechanism and dependence on the constituent materials of multilayers. Some relations between the giant magnetoresistance, the electrical resistivity of the magnetic alloys, and the anisotropic magnetoresistance are also discussed.

Inoue, J.; Maekawa, S. (Nagoya Univ. (Japan))

1993-06-01T23:59:59.000Z

404

A unified theory of superconductivity  

E-Print Network (OSTI)

In this paper, we study the reliability of BCS theory as a scientific explanation of the mystery of superconductivity. It is shown clearly that the phonon-mediated BCS theory is fundamentally incorrect. Two kinds of glues, pairing (pseudogap) glue and superconducting glue, are suggested based on a real space Coulomb confinement effect. The scenarios provide a unified explanation of the pairing symmetry, pseudogap and superconducting states, charge stripe order, spin density wave (SDW), checkerboard-type charge-ordered phase, magic doping fractions and vortex structures in conventional and unconventional (the high-Tc cuprates and MgB2) superconductors. The theory agrees with the existence of a pseudogap in high-temperature superconductors, while no pseudogap feature could be observed in MgB2 and most of the conventional superconductors. Our results indicate that the superconducting phase can coexist with a inclined hexagonal vortex lattice in pure MgB2 single crystal with a charge carrier density ps=1.49*10^{22}/cm^{3}. Finally, the physical reasons why the good conductors (for example, Ag, Au, and Cu) and the overdoped high-Tc superconductors are non-superconducting are also explored.

Xiuqing Huang

2008-04-10T23:59:59.000Z

405

A Simple Thermodynamical Theory for Dust Devils  

Science Conference Proceedings (OSTI)

Based on the heat engine framework, a simple scaling theory for dust devils is proposed and compared to observations. This theory provides a simple physical interpretation for many of the observed characteristics of dust devils. In particular, it ...

Nilton O. Rennó; Matthew L. Burkett; Matthew P. Larkin

1998-11-01T23:59:59.000Z

406

Northern Winter Stationary Waves: Theory and Modeling  

Science Conference Proceedings (OSTI)

A review is provided of stationary wave theory, the theory for the deviations from zonal symmetry of the climate. To help focus the discussion the authors concentrate exclusively on northern winter. Several theoretical issues, including the ...

Isaac M. Held; Mingfang Ting; Hailan Wang

2002-08-01T23:59:59.000Z

407

Quantum Mechanics and Representation Theory Columbia University  

E-Print Network (OSTI)

Quantum Mechanics and Representation Theory Peter Woit Columbia University Texas Tech, November 21 2013 Peter Woit (Columbia University) Quantum Mechanics and Representation Theory November 2013 1 / 30 #12;Does Anyone Understand Quantum Mechanics? "No One Understands Quantum Mechanics" "I think

Woit, Peter

408

Translational-invariant noncommutative gauge theory  

Science Conference Proceedings (OSTI)

A generalized translational-invariant noncommutative field theory is analyzed in detail, and a complete description of translational-invariant noncommutative structures is worked out. The relevant gauge theory is described, and the planar and nonplanar axial anomalies are obtained.

Ardalan, F. [Department of Physics, Sharif University of Technology, P.O. Box 11155-9161, Tehran (Iran, Islamic Republic of); Institute for Studies in Theoretical Physics and Mathematics (IPM), School of Physics, P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Sadooghi, N. [Department of Physics, Sharif University of Technology, P.O. Box 11155-9161, Tehran (Iran, Islamic Republic of)

2011-01-15T23:59:59.000Z

409

Scissors congruence and K-theory  

E-Print Network (OSTI)

In this thesis we develop a version of classical scissors congruence theory from the perspective of algebraic K-theory. Classically, two polytopes in a manifold X are defined to be scissors congruent if they can be decomposed ...

Zakharevich, Inna (Inna Ilana)

2012-01-01T23:59:59.000Z

410

BLG theory with generalized Jordan triple systems  

E-Print Network (OSTI)

We use a generalized Jordan algebra of the second kind to study the recently proposed BLG theory of multiple M2-branes. We find the restriction imposed on the ternary product from its consistency with the BLG theory.

Sudipto Paul Chowdhury; Subir Mukhopadhyay; Koushik Ray

2009-03-17T23:59:59.000Z

411

Generalized Stability Theory. Part I: Autonomous Operators  

Science Conference Proceedings (OSTI)

Classical stability theory is extended to include transient growth processes. The central role of the nonnormality of the linearized dynamical system in the stability problem is emphasized, and a generalized stability theory is constructed that ...

Brian F. Farrell; Petros J. Ioannou

1996-07-01T23:59:59.000Z

412

Fast library for number theory: an introduction  

Science Conference Proceedings (OSTI)

We discuss FLINT (Fast Library for Number Theory), a library to support computations in number theory, including highly optimised routines for polynomial arithmetic and linear algebra in exact rings.

William B. Hart

2010-09-01T23:59:59.000Z

413

Seeking String Theory in the Cosmos  

E-Print Network (OSTI)

We review the existence, formation and properties of cosmic strings in string theory, the wide variety of observational techniques that are being employed to detect them, and the constraints that current observations impose on string theory models.

Copeland, Edmund J; Vachaspati, Tanmay

2011-01-01T23:59:59.000Z

414

A Simplified HTTR Diffusion Theory Benchmark  

SciTech Connect

The Georgia Institute of Technology (GA-Tech) recently developed a transport theory benchmark based closely on the geometry and the features of the HTTR reactor that is operational in Japan. Though simplified, the benchmark retains all the principal physical features of the reactor and thus provides a realistic and challenging test for the codes. The purpose of this paper is twofold. The first goal is an extension of the benchmark to diffusion theory applications by generating the additional data not provided in the GA-Tech prior work. The second goal is to use the benchmark on the HEXPEDITE code available to the INL. The HEXPEDITE code is a Green’s function-based neutron diffusion code in 3D hexagonal-z geometry. The results showed that the HEXPEDITE code accurately reproduces the effective multiplication factor of the reference HELIOS solution. A secondary, but no less important, conclusion is that in the testing against actual HTTR data of a full sequence of codes that would include HEXPEDITE, in the apportioning of inevitable discrepancies between experiment and models, the portion of error attributable to HEXPEDITE would be expected to be modest. If large discrepancies are observed, they would have to be explained by errors in the data fed into HEXPEDITE. Results based on a fully realistic model of the HTTR reactor are presented in a companion paper. The suite of codes used in that paper also includes HEXPEDITE. The results shown here should help that effort in the decision making process for refining the modeling steps in the full sequence of codes.

Rodolfo M. Ferrer; Abderrafi M. Ougouag; Farzad Rahnema

2010-10-01T23:59:59.000Z

415

Green Functions for the Wrong-Sign Quartic  

E-Print Network (OSTI)

It has been shown that the Schwinger-Dyson equations for non-Hermitian theories implicitly include the Hilbert-space metric. Approximate Green functions for such theories may thus be obtained, without having to evaluate the metric explicitly, by truncation of the equations. Such a calculation has recently been carried out for various $PT$-symmetric theories, in both quantum mechanics and quantum field theory, including the wrong-sign quartic oscillator. For this particular theory the metric is known in closed form, making possible an independent check of these approximate results. We do so by numerically evaluating the ground-state wave-function for the equivalent Hermitian Hamiltonian and using this wave-function, in conjunction with the metric operator, to calculate the one- and two-point Green functions. We find that the Green functions evaluated by lowest-order truncation of the Schwinger-Dyson equations are already accurate at the (6-8)% level. This provides a strong justification for the method and a motivation for its extension to higher order and to higher dimensions, where the calculation of the metric is extremely difficult.

H. F. Jones

2010-02-15T23:59:59.000Z

416

Occupation-number-based energy functional for nuclear masses  

Science Conference Proceedings (OSTI)

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.

Bertolli, Michael G. [University of Tennessee, Knoxville (UTK); Papenbrock, Thomas F [ORNL; Wild, S. M. [Argonne National Laboratory (ANL)

2012-01-01T23:59:59.000Z

417

Occupation number-based energy functional for nuclear masses  

E-Print Network (OSTI)

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 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.

Bertolli, M; Wild, S

2011-01-01T23:59:59.000Z

418

Occupation number-based energy functional for nuclear masses  

E-Print Network (OSTI)

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 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.

M. Bertolli; T. Papenbrock; S. Wild

2011-10-19T23:59:59.000Z

419

Quantum Theory Event-Probability Interpretation  

Science Conference Proceedings (OSTI)

In this article the propagation of pointlike event probabilities in space is considered. New interpretation of Quantum Theory is formulated.

Quznetsov, Gunn [Chelyabinsk State University, Chelyabinsk, Ural (Russian Federation)

2011-03-28T23:59:59.000Z

420

1994 International Sherwood Fusion Theory Conference  

SciTech Connect

This report contains the abstracts of the paper presented at the 1994 International Sherwood Fusion Theory Conference.

NONE

1994-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "functional theory dft" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Spatially Resolved Porous Electrode Theory for Rechargeable ...  

Science Conference Proceedings (OSTI)

Symposium, Nanostructured Materials for Lithium Ion Batteries and for Supercapacitors. Presentation Title, Spatially Resolved Porous Electrode Theory for ...

422

Supersymmetric extensions of K field theories  

E-Print Network (OSTI)

We review the recently developed supersymmetric extensions of field theories with non-standard kinetic terms (so-called K field theories) in two an three dimensions. Further, we study the issue of topological defect formation in these supersymmetric theories. Specifically, we find supersymmetric K field theories which support topological kinks in 1+1 dimensions as well as supersymmetric extensions of the baby Skyrme model for arbitrary nonnegative potentials in 2+1 dimensions.

Adam, C; Sanchez-Guillen, J; Wereszczynski, A

2012-01-01T23:59:59.000Z

423

A solution manual for Polchinski's "String Theory"  

E-Print Network (OSTI)

We present detailed solutions to 81 of the 202 problems in J. Polchinski's two-volume textbook "String Theory".

Matthew Headrick

2008-12-23T23:59:59.000Z

424

Algebraic methods for biochemical reaction network theory  

E-Print Network (OSTI)

theory [BBCQ04, CFR08]. Convex geometry and differential geometry have also played a role in chemical reactor

Shiu, Anne

2010-01-01T23:59:59.000Z

425

A solution manual for Polchinski's "String Theory"  

E-Print Network (OSTI)

We present detailed solutions to 81 of the 202 problems in J. Polchinski's two-volume textbook "String Theory".

Headrick, Matthew

2008-01-01T23:59:59.000Z

426

The graph representation approach to topological field theory in 2 + 1 dimensions  

SciTech Connect

An alternative definition of topological quantum field theory in 2+1 dimensions is discussed. The fundamental objects in this approach are not gauge fields as in the usual approach, but non-local observables associated with graphs. The classical theory of graphs is defined by postulating a simple diagrammatic rule for computing the Poisson bracket of any two graphs. The theory is quantized by exhibiting a quantum deformation of the classical Poisson bracket algebra, which is realized as a commutator algebra on a Hilbert space of states. The wavefunctions in this graph representation'' approach are functionals on an appropriate set of graphs. This is in contrast to the usual connection representation'' approach in which the theory is defined in terms of a gauge field and the wavefunctions are functionals on the space of flat spatial connections modulo gauge transformations.

Martin, S.P.

1991-02-01T23:59:59.000Z

427

Nuclear Dynamics with Effective Field Theories  

E-Print Network (OSTI)

These are the proceedings of the international workshop on "Nuclear Dynamics with Effective Field Theories" held at Ruhr-Universitaet Bochum, Germany from July 1 to 3, 2013. The workshop focused on effective field theories of low-energy QCD, chiral perturbation theory for nuclear forces as well as few- and many-body physics. Included are a short contribution per talk.

Evgeny Epelbaum; Hermann Krebs

2013-09-05T23:59:59.000Z

428

Nuclear Dynamics with Effective Field Theories  

E-Print Network (OSTI)

These are the proceedings of the international workshop on "Nuclear Dynamics with Effective Field Theories" held at Ruhr-Universitaet Bochum, Germany from July 1 to 3, 2013. The workshop focused on effective field theories of low-energy QCD, chiral perturbation theory for nuclear forces as well as few- and many-body physics. Included are a short contribution per talk.

Epelbaum, Evgeny

2013-01-01T23:59:59.000Z

429

Towards Dark Energy from String-Theory  

E-Print Network (OSTI)

We discuss vacuum energy in string and M-theory with a focus on heterotic M-theory. In the latter theory a mechanism is described for maintaining zero vacuum energy after supersymmetry breaking. Higher-order corrections can be expected to give a sufficiently small amount of vacuum energy to possibly account for dark energy.

Axel Krause

2007-12-31T23:59:59.000Z

430

The Gluon Green's Function at Small x  

E-Print Network (OSTI)

In this contribution a recently proposed iterative procedure is used to study the BFKL gluon Green's function at next-to-leading order. This is done in QCD and in N=4 supersymmetric Yang-Mills theory. The study includes an analysis of the evolution with energy and of angular dependences. A discussion of a novel resummation of running coupling terms in the QCD case is included.

Agustin Sabio Vera

2004-08-01T23:59:59.000Z

431

Functionalized Graphene Nanoroads for Quantum Well Device  

Science Conference Proceedings (OSTI)

Using density functional theory, a series of calculations of structural and electronic properties of Si-substituted graphene were conducted. Through substituting C atoms by Si atoms on graphene in the present study, we found that the band gap of graphene can be continuously tuned with differently substitutional concentration. To utilize such substitution-induced band gap changes, we proposed a special design to fabricate graphene-based quantum well device.

Zhou, Yungang; Yang, Ping; Wang, Zhiguo; Xiao, Hai Yan; Zu, Xiaotao T.; Sun, Xin; Khaleel, Mohammad A.; Gao, Fei

2011-03-02T23:59:59.000Z

432

Star product algebras of test functions  

E-Print Network (OSTI)

We prove that the Gelfand-Shilov spaces $S^\\beta_\\alpha$ are topological algebras under the Moyal star product if and only if $\\alpha\\ge\\beta$. These spaces of test functions can be used in quantum field theory on noncommutative spacetime. The star product depends continuously in their topology on the noncommutativity parameter. We also prove that the series expansion of the Moyal product is absolutely convergent in $S^\\beta_\\alpha$ if and only if $\\beta<1/2$.

Soloviev, Michael A

2007-01-01T23:59:59.000Z

433

Spin-Gauge Theory of Gravity with Higgs-field Mechanism  

E-Print Network (OSTI)

We propose a Lorentz-covariant Yang-Mills spin-gauge theory, where the function valued Dirac matrices play the role of a non-scalar Higgs-field. As symmetry group we choose $SU(2) \\times U(1)$. After symmetry breaking a non-scalar Lorentz-covariant Higgs-field gravity appears, which can be interpreted within a classical limit as Einstein's metrical theory of gravity, where we restrict ourselves in a first step to its linearized version.

H. Dehnen; E. Hitzer

2013-06-10T23:59:59.000Z

434

Does multifractal theory of turbulence have logarithms in the scaling relations?  

E-Print Network (OSTI)

The multifractal theory of turbulence uses a saddle-point evaluation in determining the power-law behaviour of structure functions. Without suitable precautions, this could lead to the presence of logarithmic corrections, thereby violating known exact relations such as the four-fifths law. Using the theory of large deviations applied to the random multiplicative model of turbulence and calculating subdominant terms, we explain here why such corrections cannot be present.

Uriel Frisch; Marco Martins Afonso; Andrea Mazzino; Victor Yakhot

2005-06-01T23:59:59.000Z

435

Finite temperature solitons in nonlocal field theories from p-adic strings  

Science Conference Proceedings (OSTI)

Nonlocal field theories which arise from p-adic string theories have vacuum soliton solutions. We find the soliton solutions at finite temperature. These solutions become important for the partition function when the temperature exceeds m{sub s}/g{sub o}{sup 2}, where m{sub s} is the string mass scale and g{sub o} is the open string coupling.

Biswas, Tirthabir [Department of Physics, St. Cloud State University, St. Cloud, Minnesota 56301 (United States); Cembranos, Jose A. R. [William I. Fine Theoretical Physics Institute, University of Minnesota, Minneapolis, Minnesota 55455 (United States); School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Kapusta, Joseph I. [School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

2010-10-15T23:59:59.000Z

436

Multiscale modeling with carbon nanotubes  

Science Conference Proceedings (OSTI)

Technologically important nanomaterials come in all shapes and sizes. They can range from small molecules to complex composites and mixtures. Depending upon the spatial dimensions of the system and properties under investigation computer modeling of ... Keywords: DFT (density functional theory), Mesoscale modeling, Molecular modeling, NEGF (nonequilibrium Green's function), NEMS (nanoelectromechanical sensors), Nanocomposites, Nanotubes, Sensors

Amitesh Maiti

2008-02-01T23:59:59.000Z

437

First-principles quantum transport modeling of thermoelectricity in single-molecule nanojunctions with graphene nanoribbon electrodes  

Science Conference Proceedings (OSTI)

We overview the nonequilibrium Green function combined with density functional theory (NEGF-DFT) approach to modeling of independent electronic and phononic quantum transport in nanoscale thermoelectrics with examples focused on a new class of devices ... Keywords: First-principles quantum transport, Graphene nanoribbons, Molecular electronics, Thermoelectrics

Branislav K. Nikoli?; Kamal K. Saha; Troels Markussen; Kristian S. Thygesen

2012-03-01T23:59:59.000Z

438

Almost zero-dimensional PT-symmetric quantum field theories  

E-Print Network (OSTI)

In 1992 Bender, Boettcher, and Lipatov proposed in two papers a new and unusual nonperturbative calculational tool in quantum field theory. The objective was to expand the Green's functions of the quantum field theory as Taylor series in powers of the space-time dimension D. In particular, the vacuum energy for a massless \\phi^{2N} (N=1,2,3,...) quantum field theory was studied. The first two Taylor coefficients in this dimensional expansion were calculated {\\it exactly} and a set of graphical rules were devised that could be used to calculate approximately the higher coefficients in the series. This approach is mathematically valid and gives accurate results, but it has not been actively pursued and investigated. Subsequently, in 1998 Bender and Boettcher discovered that PT-symmetric quantum-mechanical Hamiltonians of the form H=p^2+x^2(ix)^\\epsilon, where \\epsilon\\geq0, have real spectra. These new kinds of complex non-Dirac-Hermitian Hamiltonians define physically acceptable quantum-mechanical theories. Th...

Bender, Carl M

2010-01-01T23:59:59.000Z

439

Cosmological Models in Modified f(R) Gravity Theories  

E-Print Network (OSTI)

The actual accelerated expansion of the universe continues being a mystery in physics. Some models had been proposed for this explanations, among them the dark energy, which however has problems of experimental character as well as theoretical. Other approximations, like modified gravity theories are an interesting alternative for this problem. Motivated in this approach we study cosmological models in f(R) theories which are natural extension of General Relativity with arbitrary functions of the Ricci scalar. One chapter has dedicated to obtain the modified field equations in the metric formalism of f(R) theories, including the discussion about boundary terms in the action. Later, we apply these equations in order to describe the dynamics of the universe, using for this as space-time, the FLRW universe. We focus our study in the problem of cosmological distances in f(R) theories. From the study of the Geodesic Deviation Equation (GDE) in this modified scenario, we obtain differential equations for the angular diameter distance, and as an extension, the Dyer-Roeder like equation in f(R) gravity.

Alejandro Guarnizo

2012-11-11T23:59:59.000Z

440

Reconciling dark energy models with f(R) theories  

E-Print Network (OSTI)

Higher order theories of gravity have recently attracted a lot of interest as alternative candidates to explain the observed cosmic acceleration without the need of introducing any scalar field. A critical ingredient is the choice of the function f(R) of the Ricci scalar curvature entering the gravity Lagrangian and determining the dynamics of the universe. We describe an efficient procedure to reconstruct f(R) from the Hubble parameter $H$ depending on the redshift z. Using the metric formulation of f(R) theories, we derive a third order linear differential equation for f(R(z)) which can be numerically solved after setting the boundary conditions on the basis of physical considerations. Since H(z) can be reconstructed from the astrophysical data, the method we present makes it possible to determine, in principle, what is the f(R) theory which best reproduces the observed cosmological dynamics. Moreover, the method allows to reconcile dark energy models with f(R) theories finding out what is the expression of f(R) which leads to the same H(z) of the given quintessence model. As interesting examples, we consider "quiessence" (dark energy with constant equation of state) and the Chaplygin gas.

S. Capozziello; V. F. Cardone; A. Troisi

2005-01-20T23:59:59.000Z

Note: This page contains sample records for the topic "functional theory dft" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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441

Thermodynamics, Hydrodynamics and Critical Phenomena in Strongly Coupled Gauge Theories.  

E-Print Network (OSTI)

??The gauge theory / string theory correspondence has led to great progress in the study of strongly-coupled gauge theories. In this work, we start with… (more)

Pagnutti, Christopher

2011-01-01T23:59:59.000Z

442

The smooth cut-off Hierarchical Reference Theory of fluids  

E-Print Network (OSTI)

We provide a comprehensive presentation of the Hierarchical Reference Theory (HRT) in the smooth cut-off formulation. A simple and self-consistent derivation of the hierarchy of differential equations is supplemented by a comparison with the known sharp cut-off HRT. Then, the theory is applied to a hard core Yukawa fluid (HCYF): a closure, based on a mean spherical approximation ansatz, is studied in detail and its intriguing relationship to the self consistent Ornstein-Zernike approximation is discussed. The asymptotic properties, close to the critical point are investigated and compared to the renormalization group results both above and below the critical temperature. The HRT free energy is always a convex function of the density, leading to flat isotherms in the two-phase region with a finite compressibility at coexistence. This makes HRT the sole liquid-state theory able to obtain directly fluid-fluid phase equilibrium without resorting to the Maxwell construction. The way the mean field free energy is modified due to the inclusion of density fluctuations suggests how to identify the spinodal curve. Thermodynamic properties and correlation functions of the HCYF are investigated for three values of the inverse Yukawa range: z=1.8, z=4 and z=7 where Monte Carlo simulations are available. The stability of the liquid-vapor critical point with respect to freezing is also studied.

Alberto Parola; Davide Pini; Luciano Reatto

2009-01-14T23:59:59.000Z

443

A New Look at the Position Operator in Quantum Theory  

E-Print Network (OSTI)

The postulate that coordinate and momentum representations are related to each other by the Fourier transform has been accepted from the beginning of quantum theory by analogy with classical electrodynamics. As a consequence, an inevitable effect in standard theory is the wave packet spreading (WPS) of the photon coordinate wave function in directions perpendicular to the photon momentum. This leads to the following paradoxes: if the major part of photons emitted by stars are in wave packet states (what is the most probable scenario) then we should see not separate stars but only an almost continuous background from all stars; no anisotropy of the CMB radiation should be observable; data on gamma-ray bursts, signals from directional radio antennas (in particular, in experiments on Shapiro delay) and signals from pulsars show no signs of WPS. In addition, a problem arises why there are no signs of WPS for protons in the LHC ring. We argue that the above postulate is based neither on strong theoretical arguments nor on experimental data and propose a new consistent definition of the position operator. Then WPS in directions perpendicular to the particle momentum is absent and the paradoxes are resolved. Different components of the new position operator do not commute with each other and, as a consequence, there is no wave function in coordinate representation. Implications of the results for entanglement, quantum locality and the problem of time in quantum theory are discussed.

Felix M. Lev

2012-07-04T23:59:59.000Z

444

On single nucleon wave functions in nuclei  

Science Conference Proceedings (OSTI)

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

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

2011-05-06T23:59:59.000Z

445

Functional quantum biology in photosynthesis and magnetoreception  

E-Print Network (OSTI)

Is there a functional role for quantum mechanics or coherent quantum effects in biological processes? While this question is as old as quantum theory, only recently have measurements on biological systems on ultra-fast time-scales shed light on a possible answer. In this review we give an overview of the two main candidates for biological systems which may harness such functional quantum effects: photosynthesis and magnetoreception. We discuss some of the latest evidence both for and against room temperature quantum coherence, and consider whether there is truly a functional role for coherence in these biological mechanisms. Finally, we give a brief overview of some more speculative examples of functional quantum biology including the sense of smell, long-range quantum tunneling in proteins, biological photoreceptors, and the flow of ions across a cell membrane.

Lambert, Neill; Cheng, Yuan-Chung; Li, Che-Ming; Chen, Guang-Yin; Nori, Franco

2012-01-01T23:59:59.000Z

446

Functional quantum biology in photosynthesis and magnetoreception  

E-Print Network (OSTI)

Is there a functional role for quantum mechanics or coherent quantum effects in biological processes? While this question is as old as quantum theory, only recently have measurements on biological systems on ultra-fast time-scales shed light on a possible answer. In this review we give an overview of the two main candidates for biological systems which may harness such functional quantum effects: photosynthesis and magnetoreception. We discuss some of the latest evidence both for and against room temperature quantum coherence, and consider whether there is truly a functional role for coherence in these biological mechanisms. Finally, we give a brief overview of some more speculative examples of functional quantum biology including the sense of smell, long-range quantum tunneling in proteins, biological photoreceptors, and the flow of ions across a cell membrane.

Neill Lambert; Yueh-Nan Chen; Yuan-Chung Cheng; Che-Ming Li; Guang-Yin Chen; Franco Nori

2012-05-04T23:59:59.000Z

447

Electromagnetic weak turbulence theory revisited  

SciTech Connect

The statistical mechanical reformulation of weak turbulence theory for unmagnetized plasmas including fully electromagnetic effects was carried out by Yoon [Phys. Plasmas 13, 022302 (2006)]. However, the wave kinetic equation for the transverse wave ignores the nonlinear three-wave interaction that involves two transverse waves and a Langmuir wave, the incoherent analogue of the so-called Raman scattering process, which may account for the third and higher-harmonic plasma emissions. The present paper extends the previous formalism by including such a term.

Yoon, P. H. [IPST, University of Maryland, College Park, Maryland 20742 (United States); Ziebell, L. F. [Instituto de Fisica, UFRGS, Porto Alegre, RS (Brazil); Gaelzer, R.; Pavan, J. [Instituto de Fisica e Matematica, UFPel, Pelotas, RS (Brazil)

2012-10-15T23:59:59.000Z

448

Nuclear forces and chiral theories  

SciTech Connect

Recent successes in ab initio calculations of light nuclei (A=2-6) will be reviewed and correlated with the dynamical consequences of chiral symmetry. The tractability of nuclear physics evinced by these results is evidence for that symmetry. The relative importance of three-nucleon forces, four-nucleon forces, multi-pion exchanges, and relativistic corrections will be discussed in the context of effective field theories and dimensional power counting. Isospin violation in the nuclear force will also be discussed in this context.

Friar, J.L. [Los Alamos National Lab., NM (United States)]|[Washington Univ., Seattle, WA (United States). Inst. for Nuclear Theory

1995-09-01T23:59:59.000Z

449

Thermodynamic theory of kinetic overshoots  

E-Print Network (OSTI)

Everything that is not prohibited is permissible. So, what is prohibited in the course of chemical reactions, heat transfer and other dissipative processes? Is it possible to “overshoot ” the equilibrium, and if yes, then how far? Thermodynamically allowed and prohibited trajectories of processes are discussed by the example of effects of equilibrium encircling. The complete theory of thermodynamically accessible states is presented. The space of all thermodynamically admissible paths is presented by projection on the “thermodynamic tree”, that is the tree of the related thermodynamic potential (entropy, free energy, free enthalpy) in the balance polyhedron. The stationary states and limit points for open systems are localized too. 1

Er N. Gorban; Gregory S. Yablonsky

2005-01-01T23:59:59.000Z

450

The General Theory of Relativity - A  

NLE Websites -- All DOE Office Websites (Extended Search)

Einstein's special theory of relativity addressed the problem of the invariant speed of light in vacuum by showing the interrelationship of space and time. The general theory of relativity showed how the shape of spacetime could explain the mechanism of gravity. A B C D E F A. Special Theory, General Theory Albert Einstein's most noted accomplishment is his theory of relativity. This theory was developed in two major stages. The first stage is known as the special theory of relativity. Its essential idea is that neither space nor time are absolute things, but relative things that depend on one's frame of reference, while the combination of space and time is a single, nonrelative entity, which remains the same regardless of one's frame of reference.

451

Functional Mellin Transforms  

E-Print Network (OSTI)

Functional integrals are defined in terms of locally compact topological groups and their associated Banach-valued Haar integrals. This approach generalizes the functional integral scheme of Cartier and DeWitt-Morette. The definition allows a construction of functional Mellin transforms. In turn, the functional Mellin transforms can be used to define functional traces, logarithms, and determinants. The associated functional integrals are useful tools for probing function spaces in general and $C^\\ast$-algebras in particular. Several interesting aspects are explored. As an application, we construct a functional Mellin representation of the quantum evolution operator.

J. LaChapelle

2013-08-05T23:59:59.000Z

452

Functional Foods Package  

Science Conference Proceedings (OSTI)

Contains five (5) titles regarding functional foods. Functional Foods Package Health - Nutrition - Biochemistry Value Packages Nutrition Health Food Science Biochemistry This Value Package includes: ...

453

Generalized Slow Roll Conditions and the Possibility of Intermediate Scale Inflation in Scalar-Tensor Theory  

E-Print Network (OSTI)

Generalized slow roll conditions and parameters are obtained for a general form of scalar-tensor theory (with no external sources), having arbitrary functions describing a nonminimal gravitational coupling F(\\phi), a Kahler-like kinetic function k(\\phi), and a scalar potential V(\\phi). These results are then used to analyze a simple toy model example of chaotic inflation with a single scalar field \\phi and a standard Higgs potential and a simple gravitational coupling function. In this type of model inflation can occur with inflaton field values at an intermediate scale of roughly 10^{11} GeV when the particle physics symmetry breaking scale is approximately 1 TeV, provided that the theory is realized within the Jordan frame. If the theory is realized in the Einstein frame, however, the intermediate scale inflation does not occur.

J. R. Morris

2001-06-06T23:59:59.000Z

454

Green's functions and hydrodynamics for isotopic binary diffusion  

E-Print Network (OSTI)

We study classical binary fluid mixtures in which densities vary on very short time (ps) and length (nm) scales, such that hydrodynamics does not apply. In a pure fluid with a localized heat pulse the breakdown of hydrodynamics was overcome using Green's functions which connect the initial densities to those at later times. Numerically it appeared that for long times the results from the Green's functions would approach hydrodynamics. In this paper we extend the Green's functions theory to binary mixtures. For the case of isothermal isobaric mutual diffusion in isotopic binary mixtures and ideal binary mixtures, which is easier to handle than heat conduction yet still non-trivial, we show analytically that in the Green's function approach one recovers hydrodynamic behaviour at long time scales provided the system reaches local equilibrium at long times. This is a first step toward giving the Green's function theory a firmer basis because it can for this case be considered as an extension of hydrodynamics.

R. van Zon; E. G. D. Cohen

2005-08-10T23:59:59.000Z

455

Bis[(1S)-1 4-azanediyl-1-(9-deazaadenin-9-yl)-1 4-dideoxy-5-methylsulfanyl-D-ribitol] tetrakis(hydrochloride) monohydrate: structure DFT energy and ligand docking results of a potent methylthioadenosine phosphorylase inhibitor found in different  

SciTech Connect

The title compound, abbreviated as 5'ThiomethylImmA, is a potent inhibitor of methylthioadenosine phosphorylase [Singh et al. (2004). Biochemistry, 43, 9-18]. The synchrotron study reported here shows that the hydrochloride salt crystallizes with two independent, nearly superimposable, dications as a monohydrate with formula 2C{sub 12}H{sub 19}N{sub 5}O{sub 2}S{sup 2+}{center_dot}4Cl{sup -}{center_dot}H{sub 2}O. Hydrogen bonding utilizing the H atoms of the dication is found to favor certain molecular conformations in the salt, which are significantly different from those found as bound in the enzyme. Ligand docking studies starting from either of these dications or related neutral structures successfully place the conformationally revised structures in the enzyme active site but only under particular hydrogen-bonding and molecular flexibility criteria. Density functional theory calculations verify the energy similarity of the indendent cations and confirm the significant energy cost of the required conformation change to the enzyme bound form. The results suggest the using crystallographically determined free ligand coordinates as starting parameters for modelling may have serious limitations.

G Gainsford; G Evans; K Johnston; M Seth

2011-12-31T23:59:59.000Z

456

Homogeneous decoherence functionals in standard and history quantum mechanics  

E-Print Network (OSTI)

General history quantum theories are quantum theories without a globally defined notion of time. Decoherence functionals represent the states in the history approach and are defined as certain bivariate complex-valued functionals on the space of all histories. However, in practical situations -- for instance in the history formulation of standard quantum mechanics -- there often is a global time direction and the homogeneous decoherence functionals are specified by their values on the subspace of homogeneous histories. In this work we study the analytic properties of (i) the standard decoherence functional in the history version of standard quantum mechanics and (ii) homogeneous decoherence functionals in general history theories. We restrict ourselves to the situation where the space of histories is given by the lattice of projections on some Hilbert space H. Among other things we prove the non-existence of a finitely valued extension for the standard decoherence functional to the space of all histories, derive a representation for the standard decoherence functional as an unbounded quadratic form with a natural representation on a Hilbert space and prove the existence of an Isham-Linden-Schreckenberg (ILS) type representation for the standard decoherence functional.

Oliver Rudolph; J. D. M. Wright

1998-07-23T23:59:59.000Z

457

6th ANL/MSU/JINA/INT FRIB Theory Workshop  

NLE Websites -- All DOE Office Websites (Extended Search)

Home Participants Program & Talks Location Access Lodging Transportation Restaurants Forms 6th ANL/MSU/JINA/INT FRIB Theory Workshop Computational Forefront in Nuclear Theory: Preparing for FRIB Argonne National Laboratory, March 23 - 26, 2010 This workshop will concentrate on advances in theoretical methods for computing properties of nuclei and reactions relevant to the experimental program at FRIB. Although we expect a significant number of talks on methods that require the largest available and planned computers, there will also be talks on new methods that do not require such large machines. Topics quantum Monte Carlo -- no-core shell model -- coupled-cluster method -- unitary correlated-operator method -- shell model -- continuum shell model -- Gamow shell model -- energy density functionals -- cranking -- heavy-ion

458

On CSP and the Algebraic Theory of Effects  

E-Print Network (OSTI)

We consider CSP from the point of view of the algebraic theory of effects, which classifies operations as effect constructors or effect deconstructors; it also provides a link with functional programming, being a refinement of Moggi's seminal monadic point of view. There is a natural algebraic theory of the constructors whose free algebra functor is Moggi's monad; we illustrate this by characterising free and initial algebras in terms of two versions of the stable failures model of CSP, one more general than the other. Deconstructors are dealt with as homomorphisms to (possibly non-free) algebras. One can view CSP's action and choice operators as constructors and the rest, such as concealment and concurrency, as deconstructors. Carrying this programme out results in taking deterministic external choice as constructor rather than general external choice. However, binary deconstructors, such as the CSP concurrency operator, provide unresolved difficulties. We conclude by presenting a combination of CSP with Mog...

van Glabbeek, Rob

2010-01-01T23:59:59.000Z

459

N >= 4 Supergravity Amplitudes from Gauge Theory at Two Loops  

SciTech Connect

We present the full two-loop four-graviton amplitudes in N = 4, 5, 6 supergravity. These results were obtained using the double-copy structure of gravity, which follows from the recently conjectured color-kinematics duality in gauge theory. The two-loop four-gluon scattering amplitudes in N = 0, 1, 2 supersymmetric gauge theory are a second essential ingredient. The gravity amplitudes have the expected infrared behavior: the two-loop divergences are given in terms of the squares of the corresponding one-loop amplitudes. The finite remainders are presented in a compact form. The finite remainder for N = 8 supergravity is also presented, in a form that utilizes a pure function with a very simple symbol.

Boucher-Veronneau, C.; Dixon, L.J.; /SLAC

2012-02-15T23:59:59.000Z

460

Type II Actions from 11-Dimensional Chern-Simons Theories  

E-Print Network (OSTI)

This paper continues the discussion of hep-th/0605038, applying the holographic formulation of self-dual theory to the Ramond-Ramond fields of type II supergravity. We formulate the RR partition function, in the presence of nontrivial H-fields, in terms of the wavefunction of an 11-dimensional Chern-Simons theory. Using the methods of hep-th/0605038 we show how to formulate an action principle for the RR fields of both type IIA and type IIB supergravity, in the presence of RR current. We find a new topological restriction on consistent backgrounds of type IIA supergravity, namely the fourth Wu class must have a lift to the H-twisted cohomology.

Dmitriy M. Belov; Gregory W. Moore

2006-11-02T23:59:59.000Z

Note: This page contains sample records for the topic "functional theory dft" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Calculation of exchange energies using algebraic perturbation theory  

Science Conference Proceedings (OSTI)

An algebraic perturbation theory is presented for efficient calculations of localized states and hence of exchange energies, which are the differences between low-lying states of the valence electron of a molecule, formed by the collision of an ion Y{sup +} with an atom X. For the case of a homonuclear molecule these are the gerade and ungerade states and the exchange energy is an exponentially decreasing function of the internuclear distance. For such homonuclear systems the theory is used in conjunction with the Herring-Holstein technique to give accurate exchange energies for a range of intermolecular separations R. Since the perturbation parameter is essentially 1/R, this method is suitable for large R. In particular, exchange energies are calculated for X{sub 2}{sup +} systems, where X is H, Li, Na, K, Rb, or Cs.

Burrows, B. L. [Mathematics Section Faculty of Computing, Engineering and Technology Staffordshire University, Beaconside, Stafford ST18 0DG (United Kingdom); Dalgarno, A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138 (United States); Cohen, M. [Department of Physical Chemistry, Hebrew University of Jerusalem, Jerusalem IL-91904 (Israel)

2010-04-15T23:59:59.000Z

462

Modulated Ground State of Gravity Theories with Stabilized Conformal Factor  

E-Print Network (OSTI)

We discuss the stabilization of the conformal factor by higher derivative terms in a conformally reduced $R+R^2$ Euclidean gravity theory. The flat spacetime is unstable towards the condensation of modes with nonzero momentum, and they "condense" in a modulated phase above a critical value of the coupling $\\beta$ of the $R^2$ term. By employing a combination of variational, numerical and lattice methods we show that in the semiclassical limit the corresponding functional integral is dominated by a single nonlinear plane wave of frequency $\\approx 1/\\sqrt{\\beta} \\lp$. We argue that the ground state of the theory is characterized by a spontaneous breaking of translational invariance at Planckian scales.

Bonanno, Alfio

2013-01-01T23:59:59.000Z

463

Scaling Deviations for Neutrino Reactions in Aysmptotically Free Field Theories  

DOE R&D Accomplishments (OSTI)

Several aspects of deep inelastic neutrino scattering are discussed in the framework of asymptotically free field theories. We first consider the growth behavior of the total cross sections at large energies. Because of the deviations from strict scaling which are characteristic of such theories the growth need not be linear. However, upper and lower bounds are established which rather closely bracket a linear growth. We next consider in more detail the expected pattern of scaling deviation for the structure functions and, correspondingly, for the differential cross sections. The analysis here is based on certain speculative assumptions. The focus is on qualitative effects of scaling breakdown as they may show up in the X and y distributions. The last section of the paper deals with deviations from the Callan-Gross relation.

Wilczek, F. A.; Zee, A.; Treiman, S. B.

1974-11-01T23:59:59.000Z

464

D-brane Instantons in Type II String Theory  

Science Conference Proceedings (OSTI)

We review recent progress in determining the effects of D-brane instantons in N=1 supersymmetric compactifications of Type II string theory to four dimensions. We describe the abstract D-brane instanton calculus for holomorphic couplings such as the superpotential, the gauge kinetic function and higher fermionic F-terms. This includes a discussion of multi-instanton effects and the implications of background fluxes for the instanton sector. Our presentation also highlights, but is not restricted to the computation of D-brane instanton effects in quiver gauge theories on D-branes at singularities. We then summarize the concrete consequences of stringy D-brane instantons for the construction of semi-realistic models of particle physics or SUSY-breaking in compact and non-compact geometries.

Blumenhagen, Ralph; /Munich, Max Planck Inst.; Cvetic, Mirjam; /Pennsylvania U.; Kachru, Shamit; /Stanford U., Phys. Dept. /SLAC; Weigand, Timo; /SLAC

2009-06-19T23:59:59.000Z

465

A kinematic wave theory of capacity drop  

E-Print Network (OSTI)

Capacity drop at active bottlenecks is one of the most puzzling traffic phenomena, but a thorough understanding is practically important for designing variable speed limit and ramp metering strategies. In this study, we attempt to develop a simple model of capacity drop within the framework of kinematic wave theory based on the observation that capacity drop occurs when an upstream queue forms at an active bottleneck. In addition, we assume that the fundamental diagrams are continuous in steady states. This assumption is consistent with observations and can avoid unrealistic infinite characteristic wave speeds in discontinuous fundamental diagrams. A core component of the new model is an entropy condition defined by a discontinuous boundary flux function. For a lane-drop area, we demonstrate that the model is well-defined, and its Riemann problem can be uniquely solved. We theoretically discuss traffic stability with this model subject to perturbations in density, upstream demand, and downstream supply. We clarify that discontinuous flow-density relations, or so-called "discontinuous" fundamental diagrams, are caused by incomplete observations of traffic states. Theoretical results are consistent with observations in the literature and are verified by numerical simulations and empirical observations. We finally discuss potential applications and future studies.

Wen-Long Jin; Qi-Jian Gan; Jean-Patrick Lebacque

2013-10-09T23:59:59.000Z

466

16. Heavy-Quark and Soft-Collinear Effective Theory 1 16. Heavy-Quark and Soft-Collinear Effective Theory  

E-Print Network (OSTI)

16. Heavy-Quark and Soft-Collinear Effective Theory 1 16. Heavy-Quark and Soft-Collinear Effective the quantum fluctuations of such heavy particles are "integrated out" from the generating functional integral. Beringer et al.(PDG), PR D86, 010001 (2012) (http://pdg.lbl.gov) June 18, 2012 16:19 #12;2 16. Heavy

467

Transportation Organization and Functions  

Energy.gov (U.S. Department of Energy (DOE))

Office of Packaging and Transportation list of organizations and functions, with a list of acronyms.

468

Functional Properties Staff  

Science Conference Proceedings (OSTI)

... Methods Group Staff; Materials Measurement Science Division Staff Directory; MML Organization. Contact. Functional Properties ...

2013-04-30T23:59:59.000Z

469

Rosenfeld functional for non-additive hard spheres  

E-Print Network (OSTI)

The fundamental measure density functional theory for hard spheres is generalized to binary mixtures of arbitrary positive and moderate negative non-additivity between unlike components. In bulk the theory predicts fluid-fluid phase separation into phases with different chemical compositions. The location of the accompanying critical point agrees well with previous results from simulations over a broad range of non-additivities and both for symmetric and highly asymmetric size ratios. Results for partial pair correlation functions show good agreement with simulation data.

Matthias Schmidt

2004-07-01T23:59:59.000Z

470

A relativistically covariant version of Bohm's quantum field theory for the scalar field  

E-Print Network (OSTI)

We give a relativistically covariant, wave-functional formulation of Bohm's quantum field theory for the scalar field based on a general foliation of space-time by space-like hypersurfaces. The wave functional, which guides the evolution of the field, is space-time-foliation independent but the field itself is not. Hence, in order to have a theory in which the field may be considered a beable, some extra rule must be given to determine the foliation. We suggest one such rule based on the eigen vectors of the energy-momentum tensor of the field itself.

George Horton; Chris Dewdney

2004-07-13T23:59:59.000Z

471

Formation of Hydrogen Cottrell Atmosphere in Palladium: Theory ...  

Science Conference Proceedings (OSTI)

Symposium, Hydrogen Storage in Materials: Theory and Experiment. Presentation Title, Formation of Hydrogen Cottrell Atmosphere in Palladium: Theory and ...

472

Thermodynamics in Modified Gravity Theories  

E-Print Network (OSTI)

We demonstrate that there does exist an equilibrium description of thermodynamics on the apparent horizon in the expanding cosmological background for a wide class of modified gravity theories with the Lagrangian density $f(R, \\phi, X)$, where $R$ is the Ricci scalar and $X$ is the kinetic energy of a scalar field $\\phi$. This comes from a suitable definition of an energy momentum tensor of the "dark" component obeying the local energy conservation law in the Jordan frame. It is shown that the equilibrium description in terms of the horizon entropy $S$ is convenient because it takes into account the contribution of the horizon entropy $\\hat{S}$ in non-equilibrium thermodynamics as well as an entropy production term.

Kazuharu Bamba; Chao-Qiang Geng; Shinji Tsujikawa

2011-01-19T23:59:59.000Z

473

The R-matrix theory  

E-Print Network (OSTI)

The different facets of the $R$-matrix method are presented pedagogically in a general framework. Two variants have been developed over the years: $(i)$ The "calculable" $R$-matrix method is a calculational tool to derive scattering properties from the Schr\\"odinger equation in a large variety of physical problems. It was developed rather independently in atomic and nuclear physics with too little mutual influence. $(ii)$ The "phenomenological" $R$-matrix method is a technique to parametrize various types of cross sections. It was mainly (or uniquely) used in nuclear physics. Both directions are explained by starting from the simple problem of scattering by a potential. They are illustrated by simple examples in nuclear and atomic physics. In addition to elastic scattering, the $R$-matrix formalism is applied to transfer and radiative-capture reactions. We also present more recent and more ambitious applications of the theory in nuclear physics.

P. Descouvemont; D. Baye

2010-01-05T23:59:59.000Z

474

Argonne Physics Division - Theory Group  

NLE Websites -- All DOE Office Websites (Extended Search)

Division Seminar: R-150 @ 3:30pm Division Seminar: R-150 @ 3:30pm 14 April 2011 Stefano Gandolfi Los Alamos National Laboratory stefano@lanl.gov Quantum Monte Carlo Study of Strongly Correlated Fermions: Neutron Matter, Neutron Stars and Cold Atoms Division Seminar: R-150 @ 3:30pm 31 March 2011 Lucas Platter Chalmers University of Technology, Göteborg platter@chalmers.se Effective Field Theories for Nuclear Systems Division Seminar: R-150 @ 3:30pm 17 February 2011 Alexandros Gezerlis University of Washington gezerlis@uw.edu Bridging the Gap: Fermions in Nuclear Structure and Nuclear Astrophysics Special Day: Tuesday 15 February 2011 Louis H. Kauffman UIC kauffman@uic.edu Topological Quantum Information and the Jones Polynomial Division Seminar: R-150 @ 3:30pm 10 February 2011 JoaquÃ-n Drut

475

Publications Chair of Automata Theory  

E-Print Network (OSTI)

logic ALCF , which is the extension of ALC with functional roles and the feature agreement and disagreement constructors. More precisely, the set of role names of ALCF is partitioned into two sets R and F of features p = f 1 #1; #1; #1; f k and q = f 0 1 #1; #1; #1; f 0 ` , ALCF admits the additional concept

Baader, Franz

476

Supersymmetric K field theories and defect structures  

E-Print Network (OSTI)

We construct supersymmetric K field theories (i.e., theories with a non-standard kinetic term) in 1+1 and 2+1 dimensions such that the bosonic sector just consists of a nonstandard kinetic term plus a potential. Further, we study the possibility of topological defect formation in these supersymmetric models. Finally, we consider more general supersymmetric K field theories where, again, topological defects exist in some cases.

Adam, C; Sanchez-Guillen, J; Wereszczynski, A

2011-01-01T23:59:59.000Z

477

Infrared Issues in Graviton Higgs Theory  

E-Print Network (OSTI)

We investigate the one-loop infrared behaviour of the effective potential in minimally coupled graviton Higgs theory in Minkowski background. The gravitational analogue of one loop Coleman Weinberg effective potential turns out to be complex, the imaginary part indicating an infrared instability. This instability is traced to a tachyonic pole in the graviton propagator for constant Higgs fields. Physical implications of this behaviour are studied. We also discuss physical differences between gauge theories coupled to Higgs fields and graviton Higgs theory.

Srijit Bhattacharjee; Parthasarathi Majumdar

2013-01-30T23:59:59.000Z

478

Foundations of quantum theory and thermodynamics  

Science Conference Proceedings (OSTI)

Physical reasons to support the statement that Quantum theory (Quantum Gravity in particular as well as Classical Gravity) loose applicability due to Thermodynamical effects are presented. The statement is based on several points: 1. N.Bohr requirement that measuring units must have macro size is one of common fundamentals of Quantum theory. 2. The Reference System—the base notion of Classical and Quantum theory and of any observation process as well

Victor Olkhov

1998-01-01T23:59:59.000Z

479

Symmetric Boolean functions  

E-Print Network (OSTI)

Abstract—We present an extensive study of symmetric Boolean functions, especially of their cryptographic properties. Our main result establishes the link between the periodicity of the simplified value vector of a symmetric Boolean function and its degree. Besides the reduction of the amount of memory required for representing a symmetric function, this property has some consequences from a cryptographic point of view. For instance, it leads to a new general bound on the order of resiliency of symmetric functions, which improves Siegenthaler’s bound. The propagation characteristics of these functions are also addressed and the algebraic normal forms of all their derivatives are given. We finally detail the characteristics of the symmetric functions of degree at most 7, for any number of variables. Most notably, we determine all balanced symmetric functions of degree less than or equal to 7. Index Terms—Boolean functions, correlation immunity, degree, derivation, propagation criterion, resiliency, symmetric functions. I.

Anne Canteaut; Marion Videau

2004-01-01T23:59:59.000Z

480

NIST: Theory and theoretical input data  

Science Conference Proceedings (OSTI)

... electrodynamic (QED) effects such as self energy and vacuum polarization, and nuclear size and motion effects. The theory and theoretical data ...

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481

Gravity as BF theory plus potential  

E-Print Network (OSTI)

Spin foam models of quantum gravity are based on Plebanski's formulation of general relativity as a constrained BF theory. We give an alternative formulation of gravity as BF theory plus a certain potential term for the B-field. When the potential is taken to be infinitely steep one recovers general relativity. For a generic potential the theory still describes gravity in that it propagates j