Do EPR-Bell correlations require a non-local interpretation of quantum mechanics? I: Wigner approach

International Nuclear Information System (INIS)

Scully, Marlan O.; Erez, Noam; Fry, Edward S.

2005-01-01

Bell inequality experiments teach us that, to explain the data, a hidden variable theory must be non-local. But, to also apply this conclusion to quantum mechanics is unjustified. The key assumptions required to obtain a Bell inequality are (1) locality and (2) the assignment of meaningful (non-negative) probabilities to seemingly physical correlations (Bell expresses these correlations via 'hidden variables'). Since the Bell inequality is violated by experiment, at least one of these assumptions is wrong. The widespread conclusion that locality must be relinquished is unwarranted; rather, the previously mentioned correlations are not physical observables-they are not elements of physical reality

Source-Free Exchange-Correlation Magnetic Fields in Density Functional Theory.

Science.gov (United States)

Sharma, S; Gross, E K U; Sanna, A; Dewhurst, J K

2018-03-13

Spin-dependent exchange-correlation energy functionals in use today depend on the charge density and the magnetization density: E xc [ρ, m]. However, it is also correct to define the functional in terms of the curl of m for physical external fields: E xc [ρ,∇ × m]. The exchange-correlation magnetic field, B xc , then becomes source-free. We study this variation of the theory by uniquely removing the source term from local and generalized gradient approximations to the functional. By doing so, the total Kohn-Sham moments are improved for a wide range of materials for both functionals. Significantly, the moments for the pnictides are now in good agreement with experiment. This source-free method is simple to implement in all existing density functional theory codes.

New correlation potential for the local-spin-density functional formalism. II

International Nuclear Information System (INIS)

Kolar, M.; Farkas, L.

1982-01-01

Using the new parameterization for the correlation potential which seems to be the best that is at present available within the local-spin-density (LSD) functional formalism, the Fermi contact term in light atoms (up to Ni) is calculated. Although the overall improvement of the previous LSD results is obtained, discrepancy between theory and experiment remains rather large. It seems that the local approximation for exchange and correlation fails to predict such quantities as magnetic-moment density near the nucleus. It is also shown that the self-interaction correction does not remedy this failure. Further, the effect of the nonzero nuclear radius is investigated and found to be most important in the lightest atoms (e.g. a factor of 0.664 appears in the case of Li). This fact was omitted in all previous calculations and throws doubt on the reported excellent agreement of the results of many-body perturbation theory with experiment. It was also verified that the contact approximation of the Fermi contact term is really good enough. (author)

A local homology theory for linearly compact modules

International Nuclear Information System (INIS)

Nguyen Tu Cuong; Tran Tuan Nam

2004-11-01

We introduce a local homology theory for linearly modules which is in some sense dual to the local cohomology theory of A. Grothendieck. Some basic properties of local homology modules are shown such as: the vanishing and non-vanishing, the noetherianness of local homology modules. By using duality, we extend some well-known results in theory of local cohomology of A. Grothendieck. (author)

Hydrogen plasmas beyond density-functional theory: dynamic correlations and the onset of localization

International Nuclear Information System (INIS)

Perrot, F.; Dharma-Wardana, M.W.C.

1984-01-01

The density-functional theory (DFT) equations - previously considered in their application to the study of a system of ions and electrons in thermodynamic equilibrium at arbitrary temperatures and pressure - are reviewed with attention given to extending their validity in obtaining the one-electron excitation spectrum. The DFT model developed here provides structure factors and Kohn-Sham eigenstates which are then used to calculate the self-energy of the one-electron Green function, thus transcending the local-density approximations and the well-known limitations of DFT, especially with regard to the excitation spectrum. The one-particle formalism used makes contact with the multiple-scattering theories of disordered materials, liquid metals, etc., and is a necessary first step to a future calculation of two-particle propagators and related properties. 28 references

A limit for large R-charge correlators in N = 2 theories

Science.gov (United States)

Bourget, Antoine; Rodriguez-Gomez, Diego; Russo, Jorge G.

2018-05-01

Using supersymmetric localization, we study the sector of chiral primary operators (Tr ϕ 2) n with large R-charge 4 n in N = 2 four-dimensional superconformal theories in the weak coupling regime g → 0, where λ ≡ g 2 n is kept fixed as n → ∞, g representing the gauge theory coupling(s). In this limit, correlation functions G 2 n of these operators behave in a simple way, with an asymptotic behavior of the form {G}_{2n}≈ {F}_{∞}(λ){(λ/2π e)}^{2n} n α , modulo O(1 /n) corrections, with α =1/2 \\dim (g) for a gauge algebra g and a universal function F ∞(λ). As a by-product we find several new formulas both for the partition function as well as for perturbative correlators in N=2 su(N) gauge theory with 2 N fundamental hypermultiplets.

Locality and realism in contextual theories

International Nuclear Information System (INIS)

Hoekzema, D.

1987-01-01

Two types of contextual theories are distinguished and shown to be related. For theories of each type a criterion of locality is formulated which is weaker than the classical requirement of separability at spacelike intervals. The relations between the concepts of locality, realism, and ontic chance are discussed

Spin-density correlations in the dynamic spin-fluctuation theory: Comparison with polarized neutron scattering experiments

Energy Technology Data Exchange (ETDEWEB)

Melnikov, N.B., E-mail: melnikov@cs.msu.su [Lomonosov Moscow State University, Moscow 119991 (Russian Federation); Reser, B.I., E-mail: reser@imp.uran.ru [Miheev Institute of Metal Physics, Ural Branch of Russian Academy of Sciences, Ekaterinburg 620990 (Russian Federation); Paradezhenko, G.V., E-mail: gparadezhenko@cs.msu.su [Lomonosov Moscow State University, Moscow 119991 (Russian Federation)

2016-08-01

To study the spin-density correlations in the ferromagnetic metals above the Curie temperature, we relate the spin correlator and neutron scattering cross-section. In the dynamic spin-fluctuation theory, we obtain explicit expressions for the effective and local magnetic moments and spatial spin-density correlator. Our theoretical results are demonstrated by the example of bcc Fe. The effective and local moments are found in good agreement with results of polarized neutron scattering experiment over a wide temperature range. The calculated short-range order is small (up to 4 Å) and slowly decreases with temperature.

Quantum Theories of Self-Localization

Science.gov (United States)

Bernstein, Lisa Joan

In the classical dynamics of coupled oscillator systems, nonlinearity leads to the existence of stable solutions in which energy remains localized for all time. Here the quantum-mechanical counterpart of classical self-localization is investigated in the context of two model systems. For these quantum models, the terms corresponding to classical nonlinearities modify a subset of the stationary quantum states to be particularly suited to the creation of nonstationary wavepackets that localize energy for long times. The first model considered here is the Quantized Discrete Self-Trapping model (QDST), a system of anharmonic oscillators with linear dispersive coupling used to model local modes of vibration in polyatomic molecules. A simple formula is derived for a particular symmetry class of QDST systems which gives an analytic connection between quantum self-localization and classical local modes. This formula is also shown to be useful in the interpretation of the vibrational spectra of some molecules. The second model studied is the Frohlich/Einstein Dimer (FED), a two-site system of anharmonically coupled oscillators based on the Frohlich Hamiltonian and motivated by the theory of Davydov solitons in biological protein. The Born-Oppenheimer perturbation method is used to obtain approximate stationary state wavefunctions with error estimates for the FED at the first excited level. A second approach is used to reduce the first excited level FED eigenvalue problem to a system of ordinary differential equations. A simple theory of low-energy self-localization in the FED is discussed. The quantum theories of self-localization in the intrinsic QDST model and the extrinsic FED model are compared.

From the Weyl theory to a theory of locally anisotropic space-time

International Nuclear Information System (INIS)

Bogoslovsky, G.Yu.

1991-01-01

It is shown that Weyl ideas, pertaining to local conformal invariance, find natural embodiment within the framework of a relativistic theory based on a viable Finslerian model of space-time. This is associated with the peculiar property of the conformal invariant Finslerian metric which describes a locally anisotropic space of events. The local conformal transformations of the Riemannian metric tensor leave invariant rest masses as well as all observables and thus appear as local gauge transformations. The corresponding Finslerian theory of gravitation turns out, as a result, to be an Abelian gauge theory. It satisfies the principle of correspondence with Einstein theory and predicts a number of nontrivial physical effects accessible for experimental test under laboratory conditions. 13 refs

H3+-WZNW correlators from Liouville theory

International Nuclear Information System (INIS)

Ribault, Sylvain; Teschner, Joerg

2005-01-01

We prove that arbitrary correlation functions of the H 3 + -WZNW model on a sphere have a simple expression in terms of Liouville theory correlation functions. This is based on the correspondence between the KZ and BPZ equations, and on relations between the structure constants of Liouville theory and the H 3 + -WZNW model. In the critical level limit, these results imply a direct link between eigenvectors of the Gaudin hamiltonians and the problem of uniformization of Riemann surfaces. We also present an expression for correlation functions of the SL(2)/U(1) gauged WZNW model in terms of correlation functions in Liouville theory

Local observables in non-Abelian gauge theories

International Nuclear Information System (INIS)

Sharatchandra, H.S.

1981-09-01

Labelling of the physical states of a non-Abelian gauge theory on a lattice in terms of local observables in considered. The labelling is in terms of local color electric field observables and (separately) local color magnetic field observables. Matter field is also included. The non-local variables required when space is multiply-connected, are specified. Non-Abelian version of the Stokes' theorem is considered. Relevance to the continuum theory is discussed in detail. (orig.)

The generally covariant locality principle - a new paradigm for local quantum field theory

International Nuclear Information System (INIS)

Brunetti, R.; Fredenhagen, K.; Verch, R.

2002-05-01

A new approach to the model-independent description of quantum field theories will be introduced in the present work. The main feature of this new approach is to incorporate in a local sense the principle of general covariance of general relativity, thus giving rise to the concept of a locally covariant quantum field theory. Such locally covariant quantum field theories will be described mathematically in terms of covariant functors between the categories, on one side, of globally hyperbolic spacetimes with isometric embeddings as morphisms and, on the other side, of *-algebras with unital injective *-endomorphisms as morphisms. Moreover, locally covariant quantum fields can be described in this framework as natural transformations between certain functors. The usual Haag-Kastler framework of nets of operator-algebras over a fixed spacetime background-manifold, together with covariant automorphic actions of the isometry-group of the background spacetime, can be re-gained from this new approach as a special case. Examples of this new approach are also outlined. In case that a locally covariant quantum field theory obeys the time-slice axiom, one can naturally associate to it certain automorphic actions, called ''relative Cauchy-evolutions'', which describe the dynamical reaction of the quantum field theory to a local change of spacetime background metrics. The functional derivative of a relative Cauchy-evolution with respect to the spacetime metric is found to be a divergence-free quantity which has, as will be demonstrated in an example, the significance of an energy-momentum tensor for the locally covariant quantum field theory. Furthermore, we discuss the functorial properties of state spaces of locally covariant quantum field theories that entail the validity of the principle of local definiteness. (orig.)

Correlated effective field theory in transition metal compounds

International Nuclear Information System (INIS)

Mukhopadhyay, Subhasis; Chatterjee, Ibha

2004-01-01

Mean field theory is good enough to study the physical properties at higher temperatures and in higher dimensions. It explains the critical phenomena in a restricted sense. Near the critical temperatures, when fluctuations become important, it may not give the correct results. Similarly in low dimensions, the correlations become important and the mean field theory seems to be inadequate to explain the physical phenomena. At low-temperatures too, the quantum correlations become important and these effects are to be treated in an appropriate way. In 1974, Prof. M.E. Lines of Bell Laboratories, developed a theory which goes beyond the mean field theory and is known as the correlated effective field (CEF) theory. It takes into account the fluctuations in a semiempirical way. Lines and his collaborators used this theory to explain the short-range correlations and their anisotropy in the paramagnetic phase. Later Suzuki et al., Chatterjee and Desai, Mukhopadhyay and Chatterjee applied this theory to the magnetically ordered phase and a tremendous success of the theory has been found in real systems. The success of the CEF theory is discussed in this review. In order to highlight the success of this theory, earlier effective field theories and their improvements over mean field theories e.g., Bethe-Peierls-Weiss method, reaction field approximation, etc., are also discussed in this review for completeness. The beauty of the CEF theory is that it is mean field-like, but captures the essential physics of real systems to a great extent. However, this is a weak correlated theory and as a result is inappropriate for the metallic phase when strong correlations become important. In recent times, transition metal oxides become important due to the discovery of the high-temperature superconductivity and the colossal magnetoresistance phenomena. These oxides seem to be Mott insulators and undergo an insulator to metal transition by applying magnetic field, pressure and by changing

Mott-Hubbard transition and Anderson localization: A generalized dynamical mean-field theory approach

International Nuclear Information System (INIS)

Kuchinskii, E. Z.; Nekrasov, I. A.; Sadovskii, M. V.

2008-01-01

The DOS, the dynamic (optical) conductivity, and the phase diagram of a strongly correlated and strongly disordered paramagnetic Anderson-Hubbard model are analyzed within the generalized dynamical mean field theory (DMFT + Σ approximation). Strong correlations are taken into account by the DMFT, and disorder is taken into account via an appropriate generalization of the self-consistent theory of localization. The DMFT effective single-impurity problem is solved by a numerical renormalization group (NRG); we consider the three-dimensional system with a semielliptic DOS. The correlated metal, Mott insulator, and correlated Anderson insulator phases are identified via the evolution of the DOS and dynamic conductivity, demonstrating both the Mott-Hubbard and Anderson metal-insulator transition and allowing the construction of the complete zero-temperature phase diagram of the Anderson-Hubbard model. Rather unusual is the possibility of a disorder-induced Mott insulator-to-metal transition

Local algebras in Euclidean quantum field theory

International Nuclear Information System (INIS)

Guerra, Francesco.

1975-06-01

The general structure of the local observable algebras of Euclidean quantum field theory is described, considering the very simple examples of the free scalar field, the vector meson field, and the electromagnetic field. The role of Markov properties, and the relations between Euclidean theory and Hamiltonian theory in Minkowski space-time are especially emphasized. No conflict appears between covariance (in the Euclidean sense) and locality (in the Markov sense) on one hand and positive definiteness of the metric on the other hand [fr

Quasi-particle energy spectra in local reduced density matrix functional theory.

Science.gov (United States)

Lathiotakis, Nektarios N; Helbig, Nicole; Rubio, Angel; Gidopoulos, Nikitas I

2014-10-28

Recently, we introduced [N. N. Lathiotakis, N. Helbig, A. Rubio, and N. I. Gidopoulos, Phys. Rev. A 90, 032511 (2014)] local reduced density matrix functional theory (local RDMFT), a theoretical scheme capable of incorporating static correlation effects in Kohn-Sham equations. Here, we apply local RDMFT to molecular systems of relatively large size, as a demonstration of its computational efficiency and its accuracy in predicting single-electron properties from the eigenvalue spectrum of the single-particle Hamiltonian with a local effective potential. We present encouraging results on the photoelectron spectrum of molecular systems and the relative stability of C20 isotopes. In addition, we propose a modelling of the fractional occupancies as functions of the orbital energies that further improves the efficiency of the method useful in applications to large systems and solids.

Non-local charges in local quantum field theory

International Nuclear Information System (INIS)

Buchholz, D.; Lopuszanski, J.T.; Rabsztyn, S.

1985-05-01

Non-local charges are studied in the general setting of local quantum field theory. It is shown, that these charges can be represented as polynomials in the incoming respectively outgoing fields with coefficients (kernels) which are subject to specific constraints. For the restricted class of models of a scalar, massive, self interacting particle in four dimensions, a more detailed analysis shows that all non-local charges of the generic type (genus 2) are products of generators of the Poincare group. This analysis, which is based on the macroscopic causality properties of the S-matrix, seems to indicate that less trivial examples of non-local charges can only exist in two dimensions. (orig.)

Density functional theory and dynamical mean-field theory. A way to model strongly correlated systems

International Nuclear Information System (INIS)

Backes, Steffen

2017-04-01

The study of the electronic properties of correlated systems is a very diverse field and has lead to valuable insight into the physics of real materials. In these systems, the decisive factor that governs the physical properties is the ratio between the electronic kinetic energy, which promotes delocalization over the lattice, and the Coulomb interaction, which instead favours localized electronic states. Due to this competition, correlated electronic systems can show unique and interesting properties like the Metal-Insulator transition, diverse phase diagrams, strong temperature dependence and in general a high sensitivity to the environmental conditions. A theoretical description of these systems is not an easy task, since perturbative approaches that do not preserve the competition between the kinetic and interaction terms can only be applied in special limiting cases. One of the most famous approaches to obtain the electronic properties of a real material is the ab initio density functional theory (DFT) method. It allows one to obtain the ground state density of the system under investigation by mapping onto an effective non-interacting system that has to be found self-consistently. While being an exact theory, in practical implementations certain approximations have to be made to the exchange-correlation potential. The local density approximation (LDA), which approximates the exchange-correlation contribution to the total energy by that of a homogeneous electron gas with the corresponding density, has proven quite successful in many cases. Though, this approximation in general leads to an underestimation of electronic correlations and is not able to describe a metal-insulator transition due to electronic localization in the presence of strong Coulomb interaction. A different approach to the interacting electronic problem is the dynamical mean-field theory (DMFT), which is non-perturbative in the kinetic and interaction term but neglects all non-local

Density functional theory and dynamical mean-field theory. A way to model strongly correlated systems

Energy Technology Data Exchange (ETDEWEB)

Backes, Steffen

2017-04-15

The study of the electronic properties of correlated systems is a very diverse field and has lead to valuable insight into the physics of real materials. In these systems, the decisive factor that governs the physical properties is the ratio between the electronic kinetic energy, which promotes delocalization over the lattice, and the Coulomb interaction, which instead favours localized electronic states. Due to this competition, correlated electronic systems can show unique and interesting properties like the Metal-Insulator transition, diverse phase diagrams, strong temperature dependence and in general a high sensitivity to the environmental conditions. A theoretical description of these systems is not an easy task, since perturbative approaches that do not preserve the competition between the kinetic and interaction terms can only be applied in special limiting cases. One of the most famous approaches to obtain the electronic properties of a real material is the ab initio density functional theory (DFT) method. It allows one to obtain the ground state density of the system under investigation by mapping onto an effective non-interacting system that has to be found self-consistently. While being an exact theory, in practical implementations certain approximations have to be made to the exchange-correlation potential. The local density approximation (LDA), which approximates the exchange-correlation contribution to the total energy by that of a homogeneous electron gas with the corresponding density, has proven quite successful in many cases. Though, this approximation in general leads to an underestimation of electronic correlations and is not able to describe a metal-insulator transition due to electronic localization in the presence of strong Coulomb interaction. A different approach to the interacting electronic problem is the dynamical mean-field theory (DMFT), which is non-perturbative in the kinetic and interaction term but neglects all non-local

A note on the algebraic evaluation of correlators in local chiral conformal field theory

International Nuclear Information System (INIS)

Honecker, A.

1992-09-01

We comment on a program designed for the study of local chiral algebras and their representations in 2D conformal field theory. Based on the algebraic approach described by W. Nahm, this program efficiently calculates arbitrary n-point functions of these algebras. The program is designed such that calculations involving e.g. current algebras, W-algebras and N-Superconformal algebras can be performed. As a non-trivial application we construct an extension of the Virasoro algebra by two fields with spin four and six using the N=1-Super-Virasoro algebra. (orig.)

Reduced density-matrix functional theory: Correlation and spectroscopy.

Science.gov (United States)

Di Sabatino, S; Berger, J A; Reining, L; Romaniello, P

2015-07-14

In this work, we explore the performance of approximations to electron correlation in reduced density-matrix functional theory (RDMFT) and of approximations to the observables calculated within this theory. Our analysis focuses on the calculation of total energies, occupation numbers, removal/addition energies, and spectral functions. We use the exactly solvable Hubbard dimer at 1/4 and 1/2 fillings as test systems. This allows us to analyze the underlying physics and to elucidate the origin of the observed trends. For comparison, we also report the results of the GW approximation, where the self-energy functional is approximated, but no further hypothesis is made concerning the approximations of the observables. In particular, we focus on the atomic limit, where the two sites of the dimer are pulled apart and electrons localize on either site with equal probability, unless a small perturbation is present: this is the regime of strong electron correlation. In this limit, using the Hubbard dimer at 1/2 filling with or without a spin-symmetry-broken ground state allows us to explore how degeneracies and spin-symmetry breaking are treated in RDMFT. We find that, within the used approximations, neither in RDMFT nor in GW, the signature of strong correlation is present, when looking at the removal/addition energies and spectral function from the spin-singlet ground state, whereas both give the exact result for the spin-symmetry broken case. Moreover, we show how the spectroscopic properties change from one spin structure to the other.

Hidden variables and locality in quantum theory

International Nuclear Information System (INIS)

Shiva, Vandana.

1978-12-01

The status of hidden variables in quantum theory has been debated since the 1920s. The author examines the no-hidden-variable theories of von Neumann, Kochen, Specker and Bell, and finds that they all share one basic assumption: averaging over the hidden variables should reproduce the quantum mechanical probabilities. Von Neumann also makes a linearity assumption, Kochen and Specker require the preservation of certain functional relations between magnitudes, and Bell proposes a locality condition. It has been assumed that the extrastatistical requirements are needed to serve as criteria of success for the introduction of hidden variables because the statistical condition is trivially satisfied, and that Bell's result is based on a locality condition that is physically motivated. The author shows that the requirement of weak locality, which is not physically motivated, is enough to give Bell's result. The proof of Bell's inequality works equally well for any pair of commuting magnitudes satisfying a condition called the degeneracy principle. None of the no-hidden-variable proofs apply to a class of hidden variable theories that are not phase-space reconstructions of quantum mechanics. The author discusses one of these theories, the Bohm-Bub theory, and finds that hidden variable theories that re all the quantum statistics, for single and sequential measurements, must introduce a randomization process for the hidden variables after each measurement. The philosophical significance of this theory lies in the role it can play in solving the conceptual puzzles posed by quantum theory

Propositional systems in local field theories

International Nuclear Information System (INIS)

Banai, M.

1980-07-01

The authors investigate propositional systems for local field theories, which reflect intrinsically the uncertainties of measurements made on the physical system, and satisfy the isotony and local commutativity postulates of Haag and Kastler. The spacetime covariance can be implemented in natural way in these propositional systems. New techniques are introduced to obtain these propositional systems: the lattice-valued logics. The decomposition of the complete orthomodular lattice-valued logics shows that these logics are more general than the usual two-valued ones and that in these logics there is enough structure to characterize the classical and quantum, non relativistic and relativistic local field theories in a natural way. The Hilbert modules give the natural inner product ''spaces'' (modules) for the realization of the lattice-valued logics. (author)

One-Body Potential Theory of Molecules and Solids Modified Semiempirically for Electron Correlation

International Nuclear Information System (INIS)

March, N.H.

2010-08-01

The study of Cordero, March and Alonso (CMA) for four spherical atoms, Be,Ne,Mg and Ar, semiempirically fine-tunes the Hartree-Fock (HF) ground-state electron density by inserting the experimentally determined ionization potentials. The present Letter, first of all, relates this approach to the very recent work of Bartlett 'towards an exact correlated orbital theory for electrons'. Both methods relax the requirement of standard DFT that a one-body potential shall generate the exact ground-state density, though both work with high quality approximations. Unlike DFT, the CMA theory uses a modified HF non-local potential. It is finally stressed that this potential generates also an idempotent Dirac density matrix. The CMA approach is thereby demonstrated to relate, albeit approximately, to the DFT exchange-correlation potential. (author)

3d-4f magnetic interaction with density functional theory plus u approach: local Coulomb correlation and exchange pathways.

Science.gov (United States)

Zhang, Yachao; Yang, Yang; Jiang, Hong

2013-12-12

The 3d-4f exchange interaction plays an important role in many lanthanide based molecular magnetic materials such as single-molecule magnets and magnetic refrigerants. In this work, we study the 3d-4f magnetic exchange interactions in a series of Cu(II)-Gd(III) (3d(9)-4f(7)) dinuclear complexes based on the numerical atomic basis-norm-conserving pseudopotential method and density functional theory plus the Hubbard U correction approach (DFT+U). We obtain improved description of the 4f electrons by including the semicore 5s5p states in the valence part of the Gd-pseudopotential. The Hubbard U correction is employed to treat the strongly correlated Cu-3d and Gd-4f electrons, which significantly improve the agreement of the predicted exchange constants, J, with experiment, indicating the importance of accurate description of the local Coulomb correlation. The high efficiency of the DFT+U approach enables us to perform calculations with molecular crystals, which in general improve the agreement between theory and experiment, achieving a mean absolute error smaller than 2 cm(-1). In addition, through analyzing the physical effects of U, we identify two magnetic exchange pathways. One is ferromagnetic and involves an interaction between the Cu-3d, O-2p (bridge ligand), and the majority-spin Gd-5d orbitals. The other one is antiferromagnetic and involves Cu-3d, O-2p, and the empty minority-spin Gd-4f orbitals, which is suppressed by the planar Cu-O-O-Gd structure. This study demonstrates the accuracy of the DFT+U method for evaluating the 3d-4f exchange interactions, provides a better understanding of the exchange mechanism in the Cu(II)-Gd(III) complexes, and paves the way for exploiting the magnetic properties of the 3d-4f compounds containing lanthanides other than Gd.

Localizability and local gauge symmetry in quantum theory

International Nuclear Information System (INIS)

Leveille, J.P.

1976-01-01

An attempt is made to generalize a theorem of Jauch on the equivalence of local gauge symmetry and Galilean symmetry to relativistic theories. One first proves a converse to Jauch's theorem deriving the Galilei algebra from a locality postulate. When generalized to the relativistic case the locality postulate leads one to the relativistic dynamical group g 5 . A possible physical interpretation of g 5 as a relativistic dynamical group is given. An attempt to describe the dynamics solely in Minkowski space-time leads, in conjunction with the locality postulate, to a new relativistic dynamical algebra. We found that this new algebra is realized by field theoretical examples which exclude quantum electrodynamics, however, and other known gauge theories. This latter development forces one to seriously question the validity of the locality postulate. One concludes by proving a general theorem about the nonimplementability of local transformations by global operators independent of space-time in field theory

Are there realistically interpretable local theories?

International Nuclear Information System (INIS)

d'Espagnat, B.

1989-01-01

Although it rests on strongly established proofs, the statement that no realistically interpretable local theory is compatible with some experimentally testable predictions of quantum mechanics seems at first sight to be incompatible with a few general ideas and clear-cut statements occurring in recent theoretical work by Griffiths, Omnes, and Ballentine and Jarrett. It is shown here that in fact none of the developments due to these authors can be considered as a realistically interpretable local theory, so that there is no valid reason for suspecting that the existing proofs of the statement in question are all flawed

Local electric dipole moments for periodic systems via density functional theory embedding.

Science.gov (United States)

Luber, Sandra

2014-12-21

We describe a novel approach for the calculation of local electric dipole moments for periodic systems. Since the position operator is ill-defined in periodic systems, maximally localized Wannier functions based on the Berry-phase approach are usually employed for the evaluation of local contributions to the total electric dipole moment of the system. We propose an alternative approach: within a subsystem-density functional theory based embedding scheme, subset electric dipole moments are derived without any additional localization procedure, both for hybrid and non-hybrid exchange-correlation functionals. This opens the way to a computationally efficient evaluation of local electric dipole moments in (molecular) periodic systems as well as their rigorous splitting into atomic electric dipole moments. As examples, Infrared spectra of liquid ethylene carbonate and dimethyl carbonate are presented, which are commonly employed as solvents in Lithium ion batteries.

Local electric dipole moments for periodic systems via density functional theory embedding

Energy Technology Data Exchange (ETDEWEB)

Luber, Sandra, E-mail: sandra.luber@chem.uzh.ch [Institut für Chemie, Universität Zürich, Winterthurerstrasse 190, 8057 Zürich (Switzerland)

2014-12-21

We describe a novel approach for the calculation of local electric dipole moments for periodic systems. Since the position operator is ill-defined in periodic systems, maximally localized Wannier functions based on the Berry-phase approach are usually employed for the evaluation of local contributions to the total electric dipole moment of the system. We propose an alternative approach: within a subsystem-density functional theory based embedding scheme, subset electric dipole moments are derived without any additional localization procedure, both for hybrid and non-hybrid exchange–correlation functionals. This opens the way to a computationally efficient evaluation of local electric dipole moments in (molecular) periodic systems as well as their rigorous splitting into atomic electric dipole moments. As examples, Infrared spectra of liquid ethylene carbonate and dimethyl carbonate are presented, which are commonly employed as solvents in Lithium ion batteries.

Quantum theory and local causality

CERN Document Server

Hofer-Szabó, Gábor

2018-01-01

This book summarizes the results of research the authors have pursued in the past years on the problem of implementing Bell's notion of local causality in local physical theories and relating it to other important concepts and principles in the foundations of physics such as the Common Cause Principle, Bell's inequalities, the EPR (Einstein-Podolsky-Rosen) scenario, and various other locality and causality concepts. The book is intended for philosophers of science with an interest in the formal background of sciences, philosophers of physics and physicists working in foundation of physics.

Accurate and systematically improvable density functional theory embedding for correlated wavefunctions

International Nuclear Information System (INIS)

Goodpaster, Jason D.; Barnes, Taylor A.; Miller, Thomas F.; Manby, Frederick R.

2014-01-01

We analyze the sources of error in quantum embedding calculations in which an active subsystem is treated using wavefunction methods, and the remainder using density functional theory. We show that the embedding potential felt by the electrons in the active subsystem makes only a small contribution to the error of the method, whereas the error in the nonadditive exchange-correlation energy dominates. We test an MP2 correction for this term and demonstrate that the corrected embedding scheme accurately reproduces wavefunction calculations for a series of chemical reactions. Our projector-based embedding method uses localized occupied orbitals to partition the system; as with other local correlation methods, abrupt changes in the character of the localized orbitals along a reaction coordinate can lead to discontinuities in the embedded energy, but we show that these discontinuities are small and can be systematically reduced by increasing the size of the active region. Convergence of reaction energies with respect to the size of the active subsystem is shown to be rapid for all cases where the density functional treatment is able to capture the polarization of the environment, even in conjugated systems, and even when the partition cuts across a double bond

On the theory of spatial localization of photons

International Nuclear Information System (INIS)

Keller, Ole

2005-01-01

In the quantum physics of near-field optics and optical tunneling light-matter interactions are studied on a length scale (much) smaller than the wavelength of light, and questions regarding the possibilities for strong spatial localization of electromagnetic fields are here in focus. Some of these questions relate to the spatial resolution problem in optics, a problem which has gained considerable attention in connection to optical investigations of mesoscopic systems. Optics beyond the classical diffraction limit has renewed our interest in the various theories for spatial localization of single photons. In the present work aspects of these theories of particular importance for light-matter interaction on the microscopic and mesoscopic length scales are reviewed. Photon wave mechanics, i.e. the (rather unknown) first quantized theory of the photon, allows us to address the spatial field localization problem in a flexible manner which links smoothly to classical electromagnetics. The wave mechanics of free photons is discussed both in the momentum-time domain (Part A) and in the space-time domain (Part B). The first-quantized theory of spatial localization of photons subjected to field-matter interaction is described in Part C, paying particular attendance to the so-called photon energy wave function concept. In Part D, the spatial localization of photons are studied on a field theoretic (second-quantized) basis. The coarse-grained photon localization theory and the spatial localization perceived in various representations (gauges) here are core issues. In the two last parts of the review I describe photon fields in near-field optics (Part E), and the optical tunneling phenomenon, here seen as a fingerprint of weak photon localizability (Part F)

Nuclear collision theory with many-body correlations, 2

International Nuclear Information System (INIS)

Kurihara, Yukio.

1984-12-01

A nuclear collision theory, in which the many-body correlation induced by the strong short-ranged repulsion and medium-ranged attraction of the realistic NN interaction is explicitly included, is applied to the deuteron+deuteron elastic scattering at low energies. Pair correlation functions calculated by the present theory are very different from the Hackenbroich et al. 's one. They contain not only the short-ranged suppressive correlation, but also the medium-ranged enhancing correlation. The former changes the shape of the d-d potential from the wine-bottle one. And the latter makes the d-d potential much more attractive. This effect is necessary for reproducing a bump around thatesub(cm)=90 0 in the experimental elastic differential cross section. The phase shifts evaluated by the present theory are compared with those from the resonating-group method. (author)

Tetragonal fcc-Fe induced by κ -carbide precipitates: Atomic scale insights from correlative electron microscopy, atom probe tomography, and density functional theory

Science.gov (United States)

Liebscher, Christian H.; Yao, Mengji; Dey, Poulumi; Lipińska-Chwalek, Marta; Berkels, Benjamin; Gault, Baptiste; Hickel, Tilmann; Herbig, Michael; Mayer, Joachim; Neugebauer, Jörg; Raabe, Dierk; Dehm, Gerhard; Scheu, Christina

2018-02-01

Correlative scanning transmission electron microscopy, atom probe tomography, and density functional theory calculations resolve the correlation between elastic strain fields and local impurity concentrations on the atomic scale. The correlative approach is applied to coherent interfaces in a κ -carbide strengthened low-density steel and establishes a tetragonal distortion of fcc-Fe. An interfacial roughness of ˜1 nm and a localized carbon concentration gradient extending over ˜2 -3 nm is revealed, which originates from the mechano-chemical coupling between local strain and composition.

Algebraic theory of locally nilpotent derivations

CERN Document Server

Freudenburg, Gene

2017-01-01

This book explores the theory and application of locally nilpotent derivations, a subject motivated by questions in affine algebraic geometry and having fundamental connections to areas such as commutative algebra, representation theory, Lie algebras and differential equations. The author provides a unified treatment of the subject, beginning with 16 First Principles on which the theory is based. These are used to establish classical results, such as Rentschler's Theorem for the plane and the Cancellation Theorem for Curves. More recent results, such as Makar-Limanov's theorem for locally nilpotent derivations of polynomial rings, are also discussed. Topics of special interest include progress in classifying additive actions on three-dimensional affine space, finiteness questions (Hilbert's 14th Problem), algorithms, the Makar-Limanov invariant, and connections to the Cancellation Problem and the Embedding Problem. A lot of new material is included in this expanded second edition, such as canonical factoriza...

Theory of L -edge spectroscopy of strongly correlated systems

Science.gov (United States)

Lüder, Johann; Schött, Johan; Brena, Barbara; Haverkort, Maurits W.; Thunström, Patrik; Eriksson, Olle; Sanyal, Biplab; Di Marco, Igor; Kvashnin, Yaroslav O.

2017-12-01

X-ray absorption spectroscopy measured at the L edge of transition metals (TMs) is a powerful element-selective tool providing direct information about the correlation effects in the 3 d states. The theoretical modeling of the 2 p →3 d excitation processes remains to be challenging for contemporary ab initio electronic structure techniques, due to strong core-hole and multiplet effects influencing the spectra. In this work, we present a realization of the method combining the density-functional theory with multiplet ligand field theory, proposed in Haverkort et al. [Phys. Rev. B 85, 165113 (2012), 10.1103/PhysRevB.85.165113]. In this approach, a single-impurity Anderson model (SIAM) is constructed, with almost all parameters obtained from first principles, and then solved to obtain the spectra. In our implementation, we adopt the language of the dynamical mean-field theory and utilize the local density of states and the hybridization function, projected onto TM 3 d states, in order to construct the SIAM. The developed computational scheme is applied to calculate the L -edge spectra for several TM monoxides. A very good agreement between the theory and experiment is found for all studied systems. The effect of core-hole relaxation, hybridization discretization, possible extensions of the method as well as its limitations are discussed.

Introduction to localization in quantum field theory

International Nuclear Information System (INIS)

Pestun, Vasily; Zabzine, Maxim

2017-01-01

This is the introductory chapter to this issue. We review the main idea of the localization technique and its brief history both in geometry and in QFT. We discuss localization in diverse dimensions and give an overview of the major applications of the localization calculations for supersymmetric theories. We explain the focus of the present issue. (topical review)

An Efficient Local Correlation Matrix Decomposition Approach for the Localization Implementation of Ensemble-Based Assimilation Methods

Science.gov (United States)

Zhang, Hongqin; Tian, Xiangjun

2018-04-01

Ensemble-based data assimilation methods often use the so-called localization scheme to improve the representation of the ensemble background error covariance (Be). Extensive research has been undertaken to reduce the computational cost of these methods by using the localized ensemble samples to localize Be by means of a direct decomposition of the local correlation matrix C. However, the computational costs of the direct decomposition of the local correlation matrix C are still extremely high due to its high dimension. In this paper, we propose an efficient local correlation matrix decomposition approach based on the concept of alternating directions. This approach is intended to avoid direct decomposition of the correlation matrix. Instead, we first decompose the correlation matrix into 1-D correlation matrices in the three coordinate directions, then construct their empirical orthogonal function decomposition at low resolution. This procedure is followed by the 1-D spline interpolation process to transform the above decompositions to the high-resolution grid. Finally, an efficient correlation matrix decomposition is achieved by computing the very similar Kronecker product. We conducted a series of comparison experiments to illustrate the validity and accuracy of the proposed local correlation matrix decomposition approach. The effectiveness of the proposed correlation matrix decomposition approach and its efficient localization implementation of the nonlinear least-squares four-dimensional variational assimilation are further demonstrated by several groups of numerical experiments based on the Advanced Research Weather Research and Forecasting model.

Loss of locality in gravitational correlators with a large number of insertions

Science.gov (United States)

Ghosh, Sudip; Raju, Suvrat

2017-09-01

We review lessons from the AdS/CFT correspondence that indicate that the emergence of locality in quantum gravity is contingent upon considering observables with a small number of insertions. Correlation functions, where the number of insertions scales with a power of the central charge of the CFT, are sensitive to nonlocal effects in the bulk theory, which arise from a combination of the effects of the bulk Gauss law and a breakdown of perturbation theory. To examine whether a similar effect occurs in flat space, we consider the scattering of massless particles in the bosonic string and the superstring in the limit, where the number of external particles, n, becomes very large. We use estimates of the volume of the Weil-Petersson moduli space of punctured Riemann surfaces to argue that string amplitudes grow factorially in this limit. We verify this factorial behavior through an extensive numerical analysis of string amplitudes at large n. Our numerical calculations rely on the observation that, in the large n limit, the string scattering amplitude localizes on the Gross-Mende saddle points, even though individual particle energies are small. This factorial growth implies the breakdown of string perturbation theory for n ˜(M/plE ) d -2 in d dimensions, where E is the typical individual particle energy. We explore the implications of this breakdown for the black hole information paradox. We show that the loss of locality suggested by this breakdown is precisely sufficient to resolve the cloning and strong subadditivity paradoxes.

Energy momentum tensor in local causal perturbation theory

International Nuclear Information System (INIS)

Prange, D.

2001-01-01

We study the energy momentum tensor in the Bogolyubov-Epstein-Glaser approach to perturbation theory. It is found to be locally conserved for a class of theories containing to derivated fields in the interaction. For the massless φ 4 -theory we derive the trace anomaly of the improved tensor. (orig.)

Set Theory Correlation Free Algorithm for HRRR Target Tracking

National Research Council Canada - National Science Library

Blasch, Erik

1999-01-01

.... Recently a few fusionists including Mahler 1 and Mori 2 are using a set theory approach for a unified data fusion theory which is a correlation free paradigm 3 This paper uses the set theory approach...

Correlation theory of crystal field and anisotropic exchange effects

DEFF Research Database (Denmark)

Lindgård, Per-Anker

1985-01-01

A general theory for including correlation effects in static and dynamic properties is presented in terms of Raccah or Stevens operators. It is explicitly developed for general crystal fields and anisotropic interactions and systems with several sublattices, like the rare earth compounds....... The theory gives explicitly a temperature dependent renormalization of both the crystal field and the interactions, and a damping of the excitations and in addition a central park component. The general theory is illustrated by a discussion of the singlet-doublet system. The correlation effects...

Effective theory of rotationally faulted multilayer graphene - the local limit

International Nuclear Information System (INIS)

Kindermann, M; First, P N

2012-01-01

Interlayer coupling in rotationally faulted graphene multilayers breaks the local sublattice-symmetry of the individual layers. Earlier we have presented a theory of this mechanism, which reduces to an effective Dirac model with space-dependent mass in an important limit. It thus makes a wealth of existing knowledge available for the study of rotationally faulted graphene multilayers. Agreement of this theory with a recent experiment in a strong magnetic field was demonstrated. Here we explore some of the predictions of this theory for the system in zero magnetic field at large interlayer bias, when it becomes local in space. We use that theory to illuminate the physics of localization and velocity renormalization in twisted graphene layers. (paper)

A generalized non-local optical response theory for plasmonic nanostructures

DEFF Research Database (Denmark)

Mortensen, N. Asger; Raza, Søren; Wubs, Martijn

2014-01-01

for their description. Here instead we present a comparatively simple semiclassical generalized non-local optical response theory that unifies quantum pressure convection effects and induced charge diffusion kinetics, with a concomitant complex-valued generalized non-local optical response parameter. Our theory...

String theory considered as a local gauge theory of an extended object

International Nuclear Information System (INIS)

Chan Hongmo; Tsou Sheungtsun.

1986-11-01

In attempting to understand more about the physical origin of the so-called 'chordal gauge symmetry' in string field theory it is found that one can, at least formally, consider the theory as a generalised local gauge theory. However, the fundamental object is no longer a point, as in ordinary gauge theory, but a point with a tail, and it is the motion of this tail which represents the internal gauge degree of freedom. Moreover, the differential geometry is based on the non-abelian conformal group instead of the usual translation group. (author)

Localization in a one-dimensional spatially correlated random potential

International Nuclear Information System (INIS)

Kasner, M.; Weller, W.

1986-01-01

The motion of an electron in a random one-dimensional spatially correlated potential is investigated. The spatial correlation is generated by a Markov chain. It is shown that the influence of the spatial correlation can be described by means of oscillating vertices usually neglected in the Berezinskii diagram technique. Correlation mainly leads to an increase of the localization length in comparison with an uncorrelated potential. However, there is a region of the parameter, where the localization decreases. (author)

The velocity correlation function in cosmic-ray diffusion theory

International Nuclear Information System (INIS)

Forman, M.A.

1977-01-01

The concept of velocity correlation functions is introduced and applied to the calculation of cosmic ray spatial diffusion coefficients. It is assumed that the pitch angle scattering coefficient is already known from some other theory, and is reasonably well-behaved. Previous results for the coefficient for diffusion parallel to the mean field are recovered when the velocity-changing mechanism is artificially restricted to pitch angle scattering. The velocity correlation method is then applied to the more general case where there are fluctuations in the local mean field. It is found that the parallel diffusion coefficient is reduced in proportion to the amplitude of the field fluctuations, and that the ratio of the perpendicular to parallel diffusion coefficients cannot be greater than 2 >/B 0 2 . It is shown in the appendix that the Liouville form of the scattering equation implies that the Fokker-Planck coefficients (Δμ 2 )/Δt=2Dsub(μμ) and (Δμ)/Δt=deltaDsub(μμ)/deltaμ, and that all higher-order coefficients are identically zero. (Auth.)

Structural predictions for Correlated Electron Materials Using the Functional Dynamical Mean Field Theory Approach

Science.gov (United States)

Haule, Kristjan

2018-04-01

The Dynamical Mean Field Theory (DMFT) in combination with the band structure methods has been able to address reach physics of correlated materials, such as the fluctuating local moments, spin and orbital fluctuations, atomic multiplet physics and band formation on equal footing. Recently it is getting increasingly recognized that more predictive ab-initio theory of correlated systems needs to also address the feedback effect of the correlated electronic structure on the ionic positions, as the metal-insulator transition is almost always accompanied with considerable structural distortions. We will review recently developed extension of merger between the Density Functional Theory (DFT) and DMFT method, dubbed DFT+ embedded DMFT (DFT+eDMFT), whichsuccessfully addresses this challenge. It is based on the stationary Luttinger-Ward functional to minimize the numerical error, it subtracts the exact double-counting of DFT and DMFT, and implements self-consistent forces on all atoms in the unit cell. In a few examples, we will also show how the method elucidated the important feedback effect of correlations on crystal structure in rare earth nickelates to explain the mechanism of the metal-insulator transition. The method showed that such feedback effect is also essential to understand the dynamic stability of the high-temperature body-centered cubic phase of elemental iron, and in particular it predicted strong enhancement of the electron-phonon coupling over DFT values in FeSe, which was very recently verified by pioneering time-domain experiment.

Generalized locally Toeplitz sequences theory and applications

CERN Document Server

Garoni, Carlo

2017-01-01

Based on their research experience, the authors propose a reference textbook in two volumes on the theory of generalized locally Toeplitz sequences and their applications. This first volume focuses on the univariate version of the theory and the related applications in the unidimensional setting, while the second volume, which addresses the multivariate case, is mainly devoted to concrete PDE applications. This book systematically develops the theory of generalized locally Toeplitz (GLT) sequences and presents some of its main applications, with a particular focus on the numerical discretization of differential equations (DEs). It is the first book to address the relatively new field of GLT sequences, which occur in numerous scientific applications and are especially dominant in the context of DE discretizations. Written for applied mathematicians, engineers, physicists, and scientists who (perhaps unknowingly) encounter GLT sequences in their research, it is also of interest to those working in the fields of...

Non-local deformation of a supersymmetric field theory

Energy Technology Data Exchange (ETDEWEB)

Zhao, Qin [National University of Singapore, Department of Physics, Singapore (Singapore); Faizal, Mir [University of Lethbridge, Department of Physics and Astronomy, Lethbridge (Canada); University of British Columbia - Okanagan, Irving K. Barber School of Arts and Sciences, Kelowna, BC (Canada); Shah, Mushtaq B.; Ganai, Prince A. [National Institute of Technology, Department of Physics, Srinagar, Kashmir (India); Bhat, Anha [National Institute of Technology, Department of Metallurgical and Materials Engineering, Srinagar (India); Zaz, Zaid [University of Kashmir, Department of Electronics and Communication Engineering, Srinagar, Kashmir (India); Masood, Syed; Raza, Jamil; Irfan, Raja Muhammad [International Islamic University, Department of Physics, Islamabad (Pakistan)

2017-09-15

In this paper, we will analyze a supersymmetric field theory deformed by generalized uncertainty principle and Lifshitz scaling. It will be observed that this deformed supersymmetric field theory contains non-local fractional derivative terms. In order to construct such a deformed N = 1 supersymmetric theory, a harmonic extension of functions will be used. However, the supersymmetry will only be preserved for a free theory and will be broken by the inclusion of interaction terms. (orig.)

The incompatibility between local hidden variable theories and the ...

Indian Academy of Sciences (India)

Thus, any theory with a different correlation function, like any ... the conservation laws goes to the core of the theories of quantized observables and ... that theories or models allowing perpetual motion are ruled out on first principles.

Describing a Strongly Correlated Model System with Density Functional Theory.

Science.gov (United States)

Kong, Jing; Proynov, Emil; Yu, Jianguo; Pachter, Ruth

2017-07-06

The linear chain of hydrogen atoms, a basic prototype for the transition from a metal to Mott insulator, is studied with a recent density functional theory model functional for nondynamic and strong correlation. The computed cohesive energy curve for the transition agrees well with accurate literature results. The variation of the electronic structure in this transition is characterized with a density functional descriptor that yields the atomic population of effectively localized electrons. These new methods are also applied to the study of the Peierls dimerization of the stretched even-spaced Mott insulator to a chain of H 2 molecules, a different insulator. The transitions among the two insulating states and the metallic state of the hydrogen chain system are depicted in a semiquantitative phase diagram. Overall, we demonstrate the capability of studying strongly correlated materials with a mean-field model at the fundamental level, in contrast to the general pessimistic view on such a feasibility.

Mermin Non-Locality in Abstract Process Theories

Directory of Open Access Journals (Sweden)

Stefano Gogioso

2015-11-01

Full Text Available The study of non-locality is fundamental to the understanding of quantum mechanics. The past 50 years have seen a number of non-locality proofs, but its fundamental building blocks, and the exact role it plays in quantum protocols, has remained elusive. In this paper, we focus on a particular flavour of non-locality, generalising Mermin's argument on the GHZ state. Using strongly complementary observables, we provide necessary and sufficient conditions for Mermin non-locality in abstract process theories. We show that the existence of more phases than classical points (aka eigenstates is not sufficient, and that the key to Mermin non-locality lies in the presence of certain algebraically non-trivial phases. This allows us to show that fRel, a favourite toy model for categorical quantum mechanics, is Mermin local. We show Mermin non-locality to be the key resource ensuring the device-independent security of the HBB CQ (N,N family of Quantum Secret Sharing protocols. Finally, we challenge the unspoken assumption that the measurements involved in Mermin-type scenarios should be complementary (like the pair X,Y, opening the doors to a much wider class of potential experimental setups than currently employed. In short, we give conditions for Mermin non-locality tests on any number of systems, where each party has an arbitrary number of measurement choices, where each measurement has an arbitrary number of outcomes and further, that works in any abstract process theory.

Global and local curvature in density functional theory.

Science.gov (United States)

Zhao, Qing; Ioannidis, Efthymios I; Kulik, Heather J

2016-08-07

Piecewise linearity of the energy with respect to fractional electron removal or addition is a requirement of an electronic structure method that necessitates the presence of a derivative discontinuity at integer electron occupation. Semi-local exchange-correlation (xc) approximations within density functional theory (DFT) fail to reproduce this behavior, giving rise to deviations from linearity with a convex global curvature that is evidence of many-electron, self-interaction error and electron delocalization. Popular functional tuning strategies focus on reproducing piecewise linearity, especially to improve predictions of optical properties. In a divergent approach, Hubbard U-augmented DFT (i.e., DFT+U) treats self-interaction errors by reducing the local curvature of the energy with respect to electron removal or addition from one localized subshell to the surrounding system. Although it has been suggested that DFT+U should simultaneously alleviate global and local curvature in the atomic limit, no detailed study on real systems has been carried out to probe the validity of this statement. In this work, we show when DFT+U should minimize deviations from linearity and demonstrate that a "+U" correction will never worsen the deviation from linearity of the underlying xc approximation. However, we explain varying degrees of efficiency of the approach over 27 octahedral transition metal complexes with respect to transition metal (Sc-Cu) and ligand strength (CO, NH3, and H2O) and investigate select pathological cases where the delocalization error is invisible to DFT+U within an atomic projection framework. Finally, we demonstrate that the global and local curvatures represent different quantities that show opposing behavior with increasing ligand field strength, and we identify where these two may still coincide.

Einstein locality, EPR locality, and the significance for science of the nonlocal character of quantum theory

International Nuclear Information System (INIS)

Stapp, H.P.

1985-10-01

The immense difference between Einstein locality and EPR locality is discussed. The latter provides a basis for establishing the nonlocal character of quantum theory, whereas the former does not. A model representing Heisenberg's idea of physical reality is introduced. It is nondeterministic and holistic: the objects, measuring devices, and their environment are treated as an inseparable entity, with, however, macroscopically localizable attributes. The EPR principle that no disturbance can propagate faster than light is imposed without assuming any structure incompatible with orthodox quantum thinking. This locality requirement renders the model incompatible with rudimentary predictions of quantum theory. A more general proof not depending on any model is also given. A recent argument that purports to show that quantum theory is compatible with EPR locality is examined. It illustrates the importance of the crucial one-world assumption. The significance for science of the failure of EPR locality is discussed

Correlation inequalities for the Yukawa2 quantum field theory

International Nuclear Information System (INIS)

Rosen, L.

1981-01-01

Correlation inequalities have been useful in statistical mechanics and quantum field theory. In particular, in the case of strongly coupled bose quantum field models such as P(phi) 2 , correlation inequalities provide the best control of the infinite volume limit. The author reports on work in which the FKG inequality was established in the Yukawa 2 quantum field theory. An elementary proof of the first Griffiths inequality is also given. (Auth.)

Local economic development in theories of regional economies and rural studies

Directory of Open Access Journals (Sweden)

Kačar Bahrija

2016-01-01

Full Text Available In this paper is a detailed analysis of the basics in the theory of economic development during the period from mid last century until today. It states the most significant theories, points out their ranges, offers a critical review regarding their treatment of development, especially regional, rural and local one. It observes those theories according to different classifications existing in scientific literature, primarily the ascend theory, stagnation theory, balanced economic growth theory; then, short-term and long-term development and growth theories; traditional and endogenous theories; economic growth stages theory emphasized after the WWII; structural changes theory; dependency theory, neo-classic counter-revolution theory and endogenous theory as a new growth theory. The analysis becomes wider with a study on development in regional economy theories and rural studies and it systematizes the classification of those theories according to regional economy academics. Distancing ourselves from any particular division as the most suitable and acceptable one, the theories are treated separately and in an historic context, in order to encircle the time framework which from modern theories, dealing with local level development difficulties, resulted. It asserts The Community-led Rural Development Theory, often referred to as the Community Development Theory, or marked as Bottom-up Partnership Approach. The analysis of development theories asserts that mixed exogenous - endogenous approach to development links the rural/local development to the globalization process mostly due to fast technology changes of the IT and communication sectors.

Physical principles, geometrical aspects, and locality properties of gauge field theories

International Nuclear Information System (INIS)

Mack, G.; Hamburg Univ.

1981-01-01

Gauge field theories, particularly Yang - Mills theories, are discussed at a classical level from a geometrical point of view. The introductory chapters are concentrated on physical principles and mathematical tools. The main part is devoted to locality problems in gauge field theories. Examples show that locality problems originate from two sources in pure Yang - Mills theories (without matter fields). One is topological and the other is related to the existence of degenerated field configurations of the infinitesimal holonomy groups on some extended region of space or space-time. Nondegenerate field configurations in theories with semisimple gauge groups can be analysed with the help of the concept of a local gauge. Such gauges play a central role in the discussion. (author)

Framing and localization in Chern-Simons theories with matter

Energy Technology Data Exchange (ETDEWEB)

Bianchi, Marco S. [Center for Research in String Theory - School of Physics and Astronomy,Queen Mary University of London,Mile End Road, London E1 4NS (United Kingdom); Griguolo, Luca [Dipartimento di Fisica e Scienze della Terra, Università di Parma andINFN Gruppo Collegato di Parma,Viale G.P. Usberti 7/A, 43100 Parma (Italy); Leoni, Matias [Physics Department, FCEyN-UBA & IFIBA-CONICET,Ciudad Universitaria, Pabellón I, 1428, Buenos Aires (Argentina); Mauri, Andrea [Dipartimento di Fisica, Università degli studi di Milano-Bicocca,Piazza della Scienza 3, I-20126 Milano (Italy); Penati, Silvia [Dipartimento di Fisica, Università degli studi di Milano-Bicocca,Piazza della Scienza 3, I-20126 Milano (Italy); INFN, Sezione di Milano-Bicocca,Piazza della Scienza 3, I-20126 Milano (Italy); Seminara, Domenico [Dipartimento di Fisica, Università di Firenze and INFN Sezione di Firenze,via G. Sansone 1, 50019 Sesto Fiorentino (Italy)

2016-06-22

Supersymmetric localization provides exact results that should match QFT computations in some regularization scheme. The agreement is particularly subtle in three dimensions where complex answers from localization procedure sometimes arise. We investigate this problem by studying the expectation value of the 1/6 BPS Wilson loop in planar ABJ(M) theory at three loops in perturbation theory. We reproduce the corresponding term in the localization result and argue that it originates entirely from a non-trivial framing of the circular contour. Contrary to pure Chern-Simons theory, we point out that for ABJ(M) the framing phase is a non-trivial function of the couplings and that it potentially receives contributions from vertex-like diagrams. Finally, we briefly discuss the intimate link between the exact framing factor and the Bremsstrahlung function of the 1/2-BPS cusp.

Quantum field theory with infinite component local fields as an alternative to the string theories

International Nuclear Information System (INIS)

Krasnikov, N.V.

1987-05-01

We show that the introduction of the infinite component local fields with higher order derivatives in the interaction makes the theory completely ultraviolet finite. For the γ 5 -anomalous theories the introduction of the infinite component field makes the theory renormalizable or superrenormalizable. (orig.)

Communication: Recovering the flat-plane condition in electronic structure theory at semi-local DFT cost

Science.gov (United States)

Bajaj, Akash; Janet, Jon Paul; Kulik, Heather J.

2017-11-01

The flat-plane condition is the union of two exact constraints in electronic structure theory: (i) energetic piecewise linearity with fractional electron removal or addition and (ii) invariant energetics with change in electron spin in a half filled orbital. Semi-local density functional theory (DFT) fails to recover the flat plane, exhibiting convex fractional charge errors (FCE) and concave fractional spin errors (FSE) that are related to delocalization and static correlation errors. We previously showed that DFT+U eliminates FCE but now demonstrate that, like other widely employed corrections (i.e., Hartree-Fock exchange), it worsens FSE. To find an alternative strategy, we examine the shape of semi-local DFT deviations from the exact flat plane and we find this shape to be remarkably consistent across ions and molecules. We introduce the judiciously modified DFT (jmDFT) approach, wherein corrections are constructed from few-parameter, low-order functional forms that fit the shape of semi-local DFT errors. We select one such physically intuitive form and incorporate it self-consistently to correct semi-local DFT. We demonstrate on model systems that jmDFT represents the first easy-to-implement, no-overhead approach to recovering the flat plane from semi-local DFT.

Deformation theory and local-global compatibility of Langlands correspondences

CERN Document Server

Luu, Martin

2015-01-01

The deformation theory of automorphic representations is used to study local properties of Galois representations associated to automorphic representations of general linear groups and symplectic groups. In some cases this allows to identify the local Galois representations with representations predicted by a local Langlands correspondence.

On the local well-posedness of Lovelock and Horndeski theories

Science.gov (United States)

Papallo, Giuseppe; Reall, Harvey S.

2017-08-01

We investigate local well-posedness of the initial value problem for Lovelock and Horndeski theories of gravity. A necessary condition for local well-posedness is strong hyperbolicity of the equations of motion. Even weak hyperbolicity can fail for strong fields so we restrict to weak fields. The Einstein equation is known to be strongly hyperbolic in harmonic gauge so we study Lovelock theories in harmonic gauge. We show that the equation of motion is always weakly hyperbolic for weak fields but, in a generic weak-field background, it is not strongly hyperbolic. For Horndeski theories, we prove that, for weak fields, the equation of motion is always weakly hyperbolic in any generalized harmonic gauge. For some Horndeski theories there exists a generalized harmonic gauge for which the equation of motion is strongly hyperbolic in a weak-field background. This includes "k-essence" like theories. However, for more general Horndeski theories, there is no generalized harmonic gauge for which the equation of motion is strongly hyperbolic in a generic weak-field background. Our results show that the standard method used to establish local well-posedness of the Einstein equation does not extend to Lovelock or general Horndeski theories. This raises the possibility that these theories may not admit a well-posed initial value problem even for weak fields.

Linear-scaling explicitly correlated treatment of solids: Periodic local MP2-F12 method

Energy Technology Data Exchange (ETDEWEB)

Usvyat, Denis, E-mail: denis.usvyat@chemie.uni-regensburg.de [Institute of Physical and Theoretical Chemistry, University of Regensburg, Universitätsstraße 31, D-93040 Regensburg (Germany)

2013-11-21

Theory and implementation of the periodic local MP2-F12 method in the 3*A fixed-amplitude ansatz is presented. The method is formulated in the direct space, employing local representation for the occupied, virtual, and auxiliary orbitals in the form of Wannier functions (WFs), projected atomic orbitals (PAOs), and atom-centered Gaussian-type orbitals, respectively. Local approximations are introduced, restricting the list of the explicitly correlated pairs, as well as occupied, virtual, and auxiliary spaces in the strong orthogonality projector to the pair-specific domains on the basis of spatial proximity of respective orbitals. The 4-index two-electron integrals appearing in the formalism are approximated via the direct-space density fitting technique. In this procedure, the fitting orbital spaces are also restricted to local fit-domains surrounding the fitted densities. The formulation of the method and its implementation exploits the translational symmetry and the site-group symmetries of the WFs. Test calculations are performed on LiH crystal. The results show that the periodic LMP2-F12 method substantially accelerates basis set convergence of the total correlation energy, and even more so the correlation energy differences. The resulting energies are quite insensitive to the resolution-of-the-identity domain sizes and the quality of the auxiliary basis sets. The convergence with the orbital domain size is somewhat slower, but still acceptable. Moreover, inclusion of slightly more diffuse functions, than those usually used in the periodic calculations, improves the convergence of the LMP2-F12 correlation energy with respect to both the size of the PAO-domains and the quality of the orbital basis set. At the same time, the essentially diffuse atomic orbitals from standard molecular basis sets, commonly utilized in molecular MP2-F12 calculations, but problematic in the periodic context, are not necessary for LMP2-F12 treatment of crystals.

Is Quantum Gravity a Super-Quantum Theory?

OpenAIRE

Chang, Lay Nam; Lewis, Zachary; Minic, Djordje; Takeuchi, Tatsu

2013-01-01

We argue that quantum gravity should be a super-quantum theory, that is, a theory whose non-local correlations are stronger than those of canonical quantum theory. As a super-quantum theory, quantum gravity should display distinct experimentally observable super-correlations of entangled stringy states.

Statistical theory of correlations in random packings of hard particles.

Science.gov (United States)

Jin, Yuliang; Puckett, James G; Makse, Hernán A

2014-05-01

A random packing of hard particles represents a fundamental model for granular matter. Despite its importance, analytical modeling of random packings remains difficult due to the existence of strong correlations which preclude the development of a simple theory. Here, we take inspiration from liquid theories for the n-particle angular correlation function to develop a formalism of random packings of hard particles from the bottom up. A progressive expansion into a shell of particles converges in the large layer limit under a Kirkwood-like approximation of higher-order correlations. We apply the formalism to hard disks and predict the density of two-dimensional random close packing (RCP), ϕ(rcp) = 0.85 ± 0.01, and random loose packing (RLP), ϕ(rlp) = 0.67 ± 0.01. Our theory also predicts a phase diagram and angular correlation functions that are in good agreement with experimental and numerical data.

Biometric feature extraction using local fractal auto-correlation

International Nuclear Information System (INIS)

Chen Xi; Zhang Jia-Shu

2014-01-01

Image texture feature extraction is a classical means for biometric recognition. To extract effective texture feature for matching, we utilize local fractal auto-correlation to construct an effective image texture descriptor. Three main steps are involved in the proposed scheme: (i) using two-dimensional Gabor filter to extract the texture features of biometric images; (ii) calculating the local fractal dimension of Gabor feature under different orientations and scales using fractal auto-correlation algorithm; and (iii) linking the local fractal dimension of Gabor feature under different orientations and scales into a big vector for matching. Experiments and analyses show our proposed scheme is an efficient biometric feature extraction approach. (condensed matter: structural, mechanical, and thermal properties)

Multiple-Trace Operators and Non-Local String Theories

International Nuclear Information System (INIS)

Silverstein, Eva M.

2001-01-01

We propose that a novel deformation of string perturbation theory, involving non-local interactions between strings, is required to describe the gravity duals of field theories deformed by multiple-trace operators. The new perturbative expansion involves a new parameter, which is neither the string coupling nor the coefficient of a vertex operator on the worldsheet. We explore some of the properties of this deformation, focusing on a special case where the deformation in the field theory is exactly marginal

Reducible gauge theories in local superfield Lagrangian BRST quantization

Energy Technology Data Exchange (ETDEWEB)

Gitman, D. M. [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Fisica; Moshin, P.Yu. [Tomsk State Pedagogical University (Russian Federation); Reshetnyak, A.A. [Inst. of Strength Physics and Materials Science, Tomsk (Russian Federation). Lab. of Non-equilibrium State Theory

2007-12-15

The construction of {theta}-local superfield Lagrangian BRST quantization in non-Abelian hyper gauges for generic gauge theories based on the action principle is examined in the case of reducible local superfield models (LSM) on the basis of embedding a gauge theory into a special {theta}-local superfield model with anti symplectic constraints and a Grassmann-odd time parameter {theta}. We examine the problem of establishing a new correspondence between the odd-Lagrangian and odd-Hamiltonian formulations of a local LSM in the case of degeneracy of the Lagrangian description with respect to derivatives over {theta} of generalized classical superfields A{sup I}({theta}). We also reveal the role of the nilpotent BRST-BFV charge for a formal dynamical system corresponding to the BV-BFV dual description of an LSM. (author)

Local Finite Density Theory, Statistical Blocking and Color Superconductivity

OpenAIRE

Ying, S.

2000-01-01

The motivation for the development of a local finite density theory is discussed. One of the problems related to an instability in the baryon number fluctuation of the chiral symmetry breaking phase of the quark system in the local theory is shown to exist. Such an instability problem is removed by taking into account the statistical blocking effects for the quark propagator, which depends on a macroscopic {\\em statistical blocking parameter} $\\epsilon$. This new frame work is then applied to...

Novel hybrid optical correlator: theory and optical simulation.

Science.gov (United States)

Casasent, D; Herold, R L

1975-02-01

The inverse transform of the product of two Fourier transform holograms is analyzed and shown to contain the correlation of the two images from which the holograms were formed. The theory, analysis, and initial experimental demonstration of the feasibility of a novel correlation scheme using this multiplied Fourier transform hologram system are presented.

Macroscopic quantum waves in non local theories

International Nuclear Information System (INIS)

Ventura, I.

1979-01-01

By means of an expansion in the density, it is shown that Macroscopic Quantum Waves also appear in non local theories. This result reinforces the conjecture that these waves should exist in liquid 4 He [pt

Quantum objects non-local correlation, causality and objective indefiniteness in the quantum world

CERN Document Server

Jaeger, Gregg

2013-01-01

This monograph identifies the essential characteristics of the objects described by current quantum theory and considers their relationship to space-time. In the process, it explicates the senses in which quantum objects may be consistently considered to have parts of which they may be composed or into which they may be decomposed. The book also demonstrates the degree to which reduction is possible in quantum mechanics, showing it to be related to the objective indefiniteness of quantum properties and the strong non-local correlations that can occur between the physical quantities of quantum

Generalized interferometry - I: theory for interstation correlations

Science.gov (United States)

Fichtner, Andreas; Stehly, Laurent; Ermert, Laura; Boehm, Christian

2017-02-01

We develop a general theory for interferometry by correlation that (i) properly accounts for heterogeneously distributed sources of continuous or transient nature, (ii) fully incorporates any type of linear and nonlinear processing, such as one-bit normalization, spectral whitening and phase-weighted stacking, (iii) operates for any type of medium, including 3-D elastic, heterogeneous and attenuating media, (iv) enables the exploitation of complete correlation waveforms, including seemingly unphysical arrivals, and (v) unifies the earthquake-based two-station method and ambient noise correlations. Our central theme is not to equate interferometry with Green function retrieval, and to extract information directly from processed interstation correlations, regardless of their relation to the Green function. We demonstrate that processing transforms the actual wavefield sources and actual wave propagation physics into effective sources and effective wave propagation. This transformation is uniquely determined by the processing applied to the observed data, and can be easily computed. The effective forward model, that links effective sources and propagation to synthetic interstation correlations, may not be perfect. A forward modelling error, induced by processing, describes the extent to which processed correlations can actually be interpreted as proper correlations, that is, as resulting from some effective source and some effective wave propagation. The magnitude of the forward modelling error is controlled by the processing scheme and the temporal variability of the sources. Applying adjoint techniques to the effective forward model, we derive finite-frequency Fréchet kernels for the sources of the wavefield and Earth structure, that should be inverted jointly. The structure kernels depend on the sources of the wavefield and the processing scheme applied to the raw data. Therefore, both must be taken into account correctly in order to make accurate inferences on

Macroscopic quantum waves in non local theories

International Nuclear Information System (INIS)

Ventura, I.

1979-01-01

By means of an expansion in the density, it is shown that Macroscopic Quantum Waves also apear in non local theories. This result reinforces the conjecture that these waves should exist in liquid 4 He. (Author) [pt

CORRELATION BETWEEN GROUP LOCAL DENSITY AND GROUP LUMINOSITY

Energy Technology Data Exchange (ETDEWEB)

Deng Xinfa [School of Science, Nanchang University, Jiangxi 330031 (China); Yu Guisheng [Department of Natural Science, Nanchang Teachers College, Jiangxi 330103 (China)

2012-11-10

In this study, we investigate the correlation between group local number density and total luminosity of groups. In four volume-limited group catalogs, we can conclude that groups with high luminosity exist preferentially in high-density regions, while groups with low luminosity are located preferentially in low-density regions, and that in a volume-limited group sample with absolute magnitude limit M{sub r} = -18, the correlation between group local number density and total luminosity of groups is the weakest. These results basically are consistent with the environmental dependence of galaxy luminosity.

Communication: Near-locality of exchange and correlation density functionals for 1- and 2-electron systems

Science.gov (United States)

Sun, Jianwei; Perdew, John P.; Yang, Zenghui; Peng, Haowei

2016-05-01

The uniform electron gas and the hydrogen atom play fundamental roles in condensed matter physics and quantum chemistry. The former has an infinite number of electrons uniformly distributed over the neutralizing positively charged background, and the latter only one electron bound to the proton. The uniform electron gas was used to derive the local spin density approximation to the exchange-correlation functional that undergirds the development of the Kohn-Sham density functional theory. We show here that the ground-state exchange-correlation energies of the hydrogen atom and many other 1- and 2-electron systems are modeled surprisingly well by a different local spin density approximation (LSDA0). LSDA0 is constructed to satisfy exact constraints but agrees surprisingly well with the exact results for a uniform two-electron density in a finite, curved three-dimensional space. We also apply LSDA0 to excited or noded 1-electron densities, where it works less well. Furthermore, we show that the localization of the exact exchange hole for a 1- or 2-electron ground state can be measured by the ratio of the exact exchange energy to its optimal lower bound.

Communication: Near-locality of exchange and correlation density functionals for 1- and 2-electron systems

Energy Technology Data Exchange (ETDEWEB)

Sun, Jianwei; Yang, Zenghui; Peng, Haowei [Department of Physics, Temple University, Philadelphia, Pennsylvania 19122 (United States); Perdew, John P. [Department of Physics, Temple University, Philadelphia, Pennsylvania 19122 (United States); Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122 (United States)

2016-05-21

The uniform electron gas and the hydrogen atom play fundamental roles in condensed matter physics and quantum chemistry. The former has an infinite number of electrons uniformly distributed over the neutralizing positively charged background, and the latter only one electron bound to the proton. The uniform electron gas was used to derive the local spin density approximation to the exchange-correlation functional that undergirds the development of the Kohn-Sham density functional theory. We show here that the ground-state exchange-correlation energies of the hydrogen atom and many other 1- and 2-electron systems are modeled surprisingly well by a different local spin density approximation (LSDA0). LSDA0 is constructed to satisfy exact constraints but agrees surprisingly well with the exact results for a uniform two-electron density in a finite, curved three-dimensional space. We also apply LSDA0 to excited or noded 1-electron densities, where it works less well. Furthermore, we show that the localization of the exact exchange hole for a 1- or 2-electron ground state can be measured by the ratio of the exact exchange energy to its optimal lower bound.

Communication: Near-locality of exchange and correlation density functionals for 1- and 2-electron systems

International Nuclear Information System (INIS)

Sun, Jianwei; Yang, Zenghui; Peng, Haowei; Perdew, John P.

2016-01-01

The uniform electron gas and the hydrogen atom play fundamental roles in condensed matter physics and quantum chemistry. The former has an infinite number of electrons uniformly distributed over the neutralizing positively charged background, and the latter only one electron bound to the proton. The uniform electron gas was used to derive the local spin density approximation to the exchange-correlation functional that undergirds the development of the Kohn-Sham density functional theory. We show here that the ground-state exchange-correlation energies of the hydrogen atom and many other 1- and 2-electron systems are modeled surprisingly well by a different local spin density approximation (LSDA0). LSDA0 is constructed to satisfy exact constraints but agrees surprisingly well with the exact results for a uniform two-electron density in a finite, curved three-dimensional space. We also apply LSDA0 to excited or noded 1-electron densities, where it works less well. Furthermore, we show that the localization of the exact exchange hole for a 1- or 2-electron ground state can be measured by the ratio of the exact exchange energy to its optimal lower bound.

Exact correlators on the Wilson loop in N=4 SYM: localization, defect CFT, and integrability

Science.gov (United States)

Giombi, Simone; Komatsu, Shota

2018-05-01

We compute a set of correlation functions of operator insertions on the 1 /8 BPS Wilson loop in N=4 SYM by employing supersymmetric localization, OPE and the Gram-Schmidt orthogonalization. These correlators exhibit a simple determinant structure, are position-independent and form a topological subsector, but depend nontrivially on the 't Hooft coupling and the rank of the gauge group. When applied to the 1 /2 BPS circular (or straight) Wilson loop, our results provide an infinite family of exact defect CFT data, including the structure constants of protected defect primaries of arbitrary length inserted on the loop. At strong coupling, we show precise agreement with a direct calculation using perturbation theory around the AdS2 string worldsheet. We also explain the connection of our results to the "generalized Bremsstrahlung functions" previously computed from integrability techniques, reproducing the known results in the planar limit as well as obtaining their finite N generalization. Furthermore, we show that the correlators at large N can be recast as simple integrals of products of polynomials (known as Q-functions) that appear in the Quantum Spectral Curve approach. This suggests an interesting interplay between localization, defect CFT and integrability.

The CPT-theorem in two-dimensional theories of local observables

International Nuclear Information System (INIS)

Borchers, H.J.

1992-01-01

Let M be a von Neumann algebra with cyclic and separating vector Ω, and let U(a) be a continuous unitary representation of R with positive generator and Ω as fixed point. If these unitaries induce for positive arguments endomorphisms of M then the modular group act as dilatations on the group of unitaries. Using this it will be shown that every theory of local observables in two dimensions, which is covariant under translations only, can be imbedded into a theory of local observables covariant under the whole Poincare group. This theory is also covariant under the CPT-transformation. (orig.)

Why two local BRS algebras in bosonic string theory

International Nuclear Information System (INIS)

Bouda, A.

1993-01-01

This paper is the first of a set of two articles in which a local Becchi-Rouet-Stora (BRS) operator for string and superstring theories is constructed by using a new procedure in which the nil potency is automatically guaranteed. In this article, it is shown that in bosonic string theory, there are two different methods of dilating the ghost which give rise to two different local BRS algebras. The first method leads to well-known results, already obtained by another procedure. The second method has been applied previously by the author. (author). 8 refs

Probing the structural and dynamical properties of liquid water with models including non-local electron correlation

International Nuclear Information System (INIS)

Del Ben, Mauro; Hutter, Jürg; VandeVondele, Joost

2015-01-01

Water is a ubiquitous liquid that displays a wide range of anomalous properties and has a delicate structure that challenges experiment and simulation alike. The various intermolecular interactions that play an important role, such as repulsion, polarization, hydrogen bonding, and van der Waals interactions, are often difficult to reproduce faithfully in atomistic models. Here, electronic structure theories including all these interactions at equal footing, which requires the inclusion of non-local electron correlation, are used to describe structure and dynamics of bulk liquid water. Isobaric-isothermal (NpT) ensemble simulations based on the Random Phase Approximation (RPA) yield excellent density (0.994 g/ml) and fair radial distribution functions, while various other density functional approximations produce scattered results (0.8-1.2 g/ml). Molecular dynamics simulation in the microcanonical (NVE) ensemble based on Møller-Plesset perturbation theory (MP2) yields dynamical properties in the condensed phase, namely, the infrared spectrum and diffusion constant. At the MP2 and RPA levels of theory, ice is correctly predicted to float on water, resolving one of the anomalies as resulting from a delicate balance between van der Waals and hydrogen bonding interactions. For several properties, obtaining quantitative agreement with experiment requires correction for nuclear quantum effects (NQEs), highlighting their importance, for structure, dynamics, and electronic properties. A computed NQE shift of 0.6 eV for the band gap and absorption spectrum illustrates the latter. Giving access to both structure and dynamics of condensed phase systems, non-local electron correlation will increasingly be used to study systems where weak interactions are of paramount importance

Non-empirical exchange-correlation parameterizations based on exact conditions from correlated orbital theory.

Science.gov (United States)

Haiduke, Roberto Luiz A; Bartlett, Rodney J

2018-05-14

Some of the exact conditions provided by the correlated orbital theory are employed to propose new non-empirical parameterizations for exchange-correlation functionals from Density Functional Theory (DFT). This reparameterization process is based on range-separated functionals with 100% exact exchange for long-range interelectronic interactions. The functionals developed here, CAM-QTP-02 and LC-QTP, show mitigated self-interaction error, correctly predict vertical ionization potentials as the negative of eigenvalues for occupied orbitals, and provide nice excitation energies, even for challenging charge-transfer excited states. Moreover, some improvements are observed for reaction barrier heights with respect to the other functionals belonging to the quantum theory project (QTP) family. Finally, the most important achievement of these new functionals is an excellent description of vertical electron affinities (EAs) of atoms and molecules as the negative of appropriate virtual orbital eigenvalues. In this case, the mean absolute deviations for EAs in molecules are smaller than 0.10 eV, showing that physical interpretation can indeed be ascribed to some unoccupied orbitals from DFT.

Non-empirical exchange-correlation parameterizations based on exact conditions from correlated orbital theory

Science.gov (United States)

Haiduke, Roberto Luiz A.; Bartlett, Rodney J.

2018-05-01

Some of the exact conditions provided by the correlated orbital theory are employed to propose new non-empirical parameterizations for exchange-correlation functionals from Density Functional Theory (DFT). This reparameterization process is based on range-separated functionals with 100% exact exchange for long-range interelectronic interactions. The functionals developed here, CAM-QTP-02 and LC-QTP, show mitigated self-interaction error, correctly predict vertical ionization potentials as the negative of eigenvalues for occupied orbitals, and provide nice excitation energies, even for challenging charge-transfer excited states. Moreover, some improvements are observed for reaction barrier heights with respect to the other functionals belonging to the quantum theory project (QTP) family. Finally, the most important achievement of these new functionals is an excellent description of vertical electron affinities (EAs) of atoms and molecules as the negative of appropriate virtual orbital eigenvalues. In this case, the mean absolute deviations for EAs in molecules are smaller than 0.10 eV, showing that physical interpretation can indeed be ascribed to some unoccupied orbitals from DFT.

Local grand unification and string theory

International Nuclear Information System (INIS)

Nilles, Hans Peter; Vaudrevange, Patrick K.S.

2009-09-01

The low energy effective action of string theory depends strongly on the process of compactification and the localization of fields in extra dimensions. Explicit string constructions towards the minimal supersymmetric standard model (MSSM) reveal interesting results leading to the concept of local grand unification. Properties of the MSSM indicate that we might live at a special location close to an orbifold fixed point rather than a generic point in Calabi-Yau moduli space. We observe an enhancement of (discrete) symmetries that have various implications for the properties of the MSSM such as proton stability as well as solutions to the flavor problem, the m-problem and the strong CP-problem. (orig.)

Theory and Algorithms for Global/Local Design Optimization

National Research Council Canada - National Science Library

Watson, Layne T; Guerdal, Zafer; Haftka, Raphael T

2005-01-01

The motivating application for this research is the global/local optimal design of composite aircraft structures such as wings and fuselages, but the theory and algorithms are more widely applicable...

Globally and locally supersymmetric effective theories for light fields

International Nuclear Information System (INIS)

Brizi, Leonardo; Gomez-Reino, Marta; Scrucca, Claudio A.

2009-01-01

We reconsider the general question of how to characterize most efficiently the low-energy effective theory obtained by integrating out heavy modes in globally and locally supersymmetric theories. We consider theories with chiral and vector multiplets and identify the conditions under which an approximately supersymmetric low-energy effective theory can exist. These conditions translate into the requirements that all the derivatives, fermions and auxiliary fields should be small in units of the heavy mass scale. They apply not only to the matter sector, but also to the gravitational one if present, and imply in that case that the gravitino mass should be small. We then show how to determine the unique exactly supersymmetric theory that approximates this effective theory at the lowest order in the counting of derivatives, fermions and auxiliary fields, by working both at the superfield level and with component fields. As a result we give a simple prescription for integrating out heavy superfields in an algebraic and manifestly supersymmetric way, which turns out to hold in the same form both for globally and locally supersymmetric theories, meaning that the process of integrating out heavy modes commutes with the process of switching on gravity. More precisely, for heavy chiral and vector multiplets one has to impose respectively stationarity of the superpotential and the Kaehler potential.

Correlations in the quantum theory of plasma line broadening

International Nuclear Information System (INIS)

Dufty, J.W.; Boercker, D.B.

1976-01-01

A unified theory of plasma line broadening is obtained from a quantum kinetic equation, paralleling existing results for a classical plasma. The atom-electron interactions are shielded by equilibrium electron correlation functions and a frequency dependent dielectric function. A 'ring' approximation is used to replace the classical plasma parameter expansion, for typical laboratory conditions. Atom-electron correlations are included as well as electron-electron correlations. (author)

The status and prospects of quantum non-local field theory

International Nuclear Information System (INIS)

Cornish, N.J.; Melbourne Univ., Parkville

1991-01-01

A critical review of the physical constraints on the form the non-locality can take is presented. The conclusion of this review is that non-locality must be restricted to interactions with the vacuum sea of virtual particles. A successful formulation of such a theory, Quantum Nonlocal Field Theory (QNFT), is applied to scalar electrodynamics and serves to illustrate how gauge invariance and manifest finiteness can be achieved. The importance of the infinite dimensional symmetry groups that occur in QNFT are discussed as an alternative to supersymmetry, the ability to generate masses by breaking the non-local symmetry with a non-invariant functional measure is given a critical assessment. To demonstrate some of the many novel applications QNFT may make possible, three disparate examples are mooted, the existence of electroweak monopoles, an mechanism for CP violation and the formulation of a finite perturbative theory of Quantum Gravity. 21 refs., ills

Local computations in Dempster-Shafer theory of evidence

Czech Academy of Sciences Publication Activity Database

Jiroušek, Radim

2012-01-01

Roč. 53, č. 8 (2012), s. 1155-1167 ISSN 0888-613X Grant - others:GA ČR(CZ) GAP403/12/2175 Program:GA Institutional support: RVO:67985556 Keywords : Discrete belief functions * Dempster-Shafer theory * conditional independence * decomposable model Subject RIV: IN - Informatics, Computer Science Impact factor: 1.729, year: 2012 http://library.utia.cas.cz/separaty/2012/MTR/jirousek-local computations in dempster–shafer theory of evidence. pdf

Hidden variable interpretation of spontaneous localization theory

Energy Technology Data Exchange (ETDEWEB)

Bedingham, Daniel J, E-mail: d.bedingham@imperial.ac.uk [Blackett Laboratory, Imperial College, London SW7 2BZ (United Kingdom)

2011-07-08

The spontaneous localization theory of Ghirardi, Rimini, and Weber (GRW) is a theory in which wavepacket reduction is treated as a genuine physical process. Here it is shown that the mathematical formalism of GRW can be given an interpretation in terms of an evolving distribution of particles on configuration space similar to Bohmian mechanics (BM). The GRW wavefunction acts as a pilot wave for the set of particles. In addition, a continuous stream of noisy information concerning the precise whereabouts of the particles must be specified. Nonlinear filtering techniques are used to determine the dynamics of the distribution of particles conditional on this noisy information and consistency with the GRW wavefunction dynamics is demonstrated. Viewing this development as a hybrid BM-GRW theory, it is argued that, besides helping to clarify the relationship between the GRW theory and BM, its merits make it worth considering in its own right.

The incompatibility between local hidden variable theories and the ...

Indian Academy of Sciences (India)

I discuss in detail the result that the Bell's inequalities derived in the context of local hidden variable theories for discrete quantized observables can be satisfied only if a fundamental conservation law is violated on the average. This result shows that such theories are physically nonviable, and makes the demarcating criteria ...

Negatively correlated local and global stock externalities: tax or subsidy?

International Nuclear Information System (INIS)

Zili Yang

2006-01-01

Fossil fuel combustion generates both CO 2 and SO 2 . CO 2 is the most important greenhouse gas; SO 2 can cause serious local pollution. But it can alleviate the potential global warming because of negative radiative forcing. Such a phenomenon can be characterized as negatively correlated local and global stock externalities. In this paper, we set up an optimal control problem of negatively correlated local and global stock externality provision. The efficiency conditions for this problem are derived. These conditions modify the Samuelson rules for optimal provision of externalities. In addition, we examine several policy related scenarios of negatively correlated local and global stock externality provisions. Finally, we discuss policy implications and limitation of the theoretical results derived in this paper. We also indicate applications of the theoretical results here to empirical research, particularly to economic analysis of multiple-gas issues in climate change. (Author)

Evolutionary theory of ageing and the problem of correlated Gompertz parameters.

Science.gov (United States)

Burger, Oskar; Missov, Trifon I

2016-11-07

The Gompertz mortality model is often used to evaluate evolutionary theories of ageing, such as the Medawar-Williams' hypothesis that high extrinsic mortality leads to faster ageing. However, fits of the Gompertz mortality model to data often find the opposite result that mortality is negatively correlated with the rate of ageing. This negative correlation has been independently discovered in several taxa and is known in actuarial studies of ageing as the Strehler-Mildvan correlation. We examine the role of mortality selection in determining late-life variation in susceptibility to death, which has been suggested to be the cause of this negative correlation. We demonstrate that fixed-frailty models that account for heterogeneity in frailty do not remove the correlation and that the correlation is an inherent statistical property of the Gompertz distribution. Linking actuarial and biological rates of ageing will continue to be a pressing challenge, but the Strehler-Mildvan correlation itself should not be used to diagnose any biological, physiological, or evolutionary process. These findings resolve some key tensions between theory and data that affect evolutionary and biological studies of ageing and mortality. Tests of evolutionary theories of ageing should include direct measures of physiological performance or condition. Copyright © 2016 Elsevier Ltd. All rights reserved.

Correlated density matrix theory of spatially inhomogeneous Bose fluids

International Nuclear Information System (INIS)

Gernoth, K.A.; Clark, J.W.; Ristig, M.L.

1994-06-01

In this paper, the variational Hartree-Jastrow theory of the ground state of spatially inhomogeneous Bose systems is extended to finite temperatures. The theory presented here is a generalization also in the sense that it extends the correlated density matrix approach, formulated previously for uniform Bose fluids, to systems with nonuniform density profiles. The method provides a framework in which the effects of thermal excitations on the spatial structure of a Bose fluid, as represented by the density profile and the two-body distribution functions, may be discussed on the basis on an ab initio microscopic description of the system. Thermal excitations make their appearance through self-consistently determined one-body and two-body potentials which enter the nonlinear, coupled Euler-Lagrange equations for the one-body density and for the pair distribution function. Since back-flow correlations are neglected, the excitations are described by a Feynman eigenvalue equation, suitably generalized to nonzero temperatures. The only external quantities entering the correlated density matrix theory elaborated here are the bare two-body interaction potential and, in actual applications, the boundary conditions to be imposed on the one-body density. 30 refs

Local models and hidden nonlocality in Quantum Theory

OpenAIRE

Guerini, Leonardo

2014-01-01

This Master's thesis has two central subjects: the simulation of correlations generated by local measurements on entangled quantum states by local hidden-variables models and the revelation of hidden nonlocality. We present and detail the Werner's local model and the hidden nonlocality of some Werner states of dimension $d\\geq5$, the Gisin-Degorre's local model for a Werner state of dimension $d=2$ and the local model of Hirsch et al. for mixtures of the singlet state and noise, all of them f...

The correlation of local deformation and stress-assisted local phase transformations in MMC foams

Energy Technology Data Exchange (ETDEWEB)

Berek, H., E-mail: harry.berek@ikgb.tu-freiberg.de [TU Bergakademie Freiberg, Agricolastraße 17, D-09599 Freiberg (Germany); Ballaschk, U.; Aneziris, C.G. [TU Bergakademie Freiberg, Agricolastraße 17, D-09599 Freiberg (Germany); Losch, K.; Schladitz, K. [Fraunhofer ITWM, Fraunhoferplatz 1, D-67663 Kaiserslautern (Germany)

2015-09-15

Cellular structures are of growing interest for industry, and are of particular importance for lightweight applications. In this paper, a special case of metal matrix composite foams (MMCs) is investigated. The investigated foams are composed of austenitic steel exhibiting transformation induced plasticity (TRIP) and magnesia partially stabilized zirconia (Mg-PSZ). Both components exhibit martensitic phase transformation during deformation, thus generating the potential for improved mechanical properties such as strength, ductility, and energy absorption capability. The aim of these investigations was to show that stress-assisted phase transformations within the ceramic reinforcement correspond to strong local deformation, and to determine whether they can trigger martensitic phase transformations in the steel matrix. To this end, in situ interrupted compression experiments were performed in an X-ray computed tomography device (XCT). By using a recently developed registration algorithm, local deformation could be calculated and regions of interest could be defined. Corresponding cross sections were prepared and used to analyze the local phase composition by electron backscatter diffraction (EBSD). The results show a strong correlation between local deformation and phase transformation. - Graphical abstract: Display Omitted - Highlights: • In situ compressive deformation on MMC foams was performed in an XCT. • Local deformation fields and their gradient amplitudes were estimated. • Cross sections were manufactured containing defined regions of interest. • Local EBSD phase analysis was performed. • Local deformation and local phase transformation are correlated.

The correlation of local deformation and stress-assisted local phase transformations in MMC foams

International Nuclear Information System (INIS)

Berek, H.; Ballaschk, U.; Aneziris, C.G.; Losch, K.; Schladitz, K.

2015-01-01

Cellular structures are of growing interest for industry, and are of particular importance for lightweight applications. In this paper, a special case of metal matrix composite foams (MMCs) is investigated. The investigated foams are composed of austenitic steel exhibiting transformation induced plasticity (TRIP) and magnesia partially stabilized zirconia (Mg-PSZ). Both components exhibit martensitic phase transformation during deformation, thus generating the potential for improved mechanical properties such as strength, ductility, and energy absorption capability. The aim of these investigations was to show that stress-assisted phase transformations within the ceramic reinforcement correspond to strong local deformation, and to determine whether they can trigger martensitic phase transformations in the steel matrix. To this end, in situ interrupted compression experiments were performed in an X-ray computed tomography device (XCT). By using a recently developed registration algorithm, local deformation could be calculated and regions of interest could be defined. Corresponding cross sections were prepared and used to analyze the local phase composition by electron backscatter diffraction (EBSD). The results show a strong correlation between local deformation and phase transformation. - Graphical abstract: Display Omitted - Highlights: • In situ compressive deformation on MMC foams was performed in an XCT. • Local deformation fields and their gradient amplitudes were estimated. • Cross sections were manufactured containing defined regions of interest. • Local EBSD phase analysis was performed. • Local deformation and local phase transformation are correlated

Correlation Theory of Static and Dynamic Properties

DEFF Research Database (Denmark)

Lindgård, Per-Anker; Yang, D.

1980-01-01

A simple and practical Green's function theory, including correlations by the memory function technique, is developed for a general magnetic Hamiltonian yielding the exact results at T → 0 and T → ∞ and giving results for any q, ω and T which are considerably more accurate than obtained by the RPA...

Correlation control theory of chaotic laser systems

International Nuclear Information System (INIS)

Li Fuli.

1986-04-01

A novel control theory of chaotic systems is studied. The correlation functions are calculated and used as feedback signals of the chaotic lasers. Computer experiments have shown that in this way the chaotic systems can be controlled to have time-independent output when the external control parameters are in chaotic domain. (author)

Bell Operator Method to Classify Local Realistic Theories

International Nuclear Information System (INIS)

Nagata, Koji

2010-01-01

We review the historical fact of multipartite Bell inequalities with an arbitrary number of settings. An explicit local realistic model for the values of a correlation function, given in a two-setting Bell experiment (two-setting model), works only for the specific set of settings in the given experiment, but cannot construct a local realistic model for the values of a correlation function, given in a continuous-infinite settings Bell experiment (infinite-setting model), even though there exist two-setting models for all directions in space. Hence, the two-setting model does not have the property that the infinite-setting model has. Here, we show that an explicit two-setting model cannot construct a local realistic model for the values of a correlation function, given in an M-setting Bell experiment (M-setting model), even though there exist two-setting models for the M measurement directions chosen in the given M-setting experiment. Hence, the two-setting model does not have the property that the M-setting model has. (general)

Generalized correlation of indefiniteness coordinate-impulse in quantum mechanics and theory of brownian movement

International Nuclear Information System (INIS)

Sukhanov, A.D.

2004-01-01

Generalized correlations of the Schroedinger indefinitenesses are shown to have the meaning of the fundamental restrictions as to characteristics of space of states in any probability-like theory. Quantum mechanics, as well as, theory of the brownian movement at arbitrary space of time fall in the category of the mentioned theories. One compared correlations of coordinates-pulse indefinitenesses within the mentioned theory with the similar correlation of indefinitenesses for microparticle under the Gaussian wave packet state. One determined that in case of profound distinction in mathematical tools of two theories one observes their conceptual resemblance. It manifests itself under the alternative conditions - short times in one theory correspond to long ones in another theory and vice versa, while in any of the mentioned theories uncontrollable effect of either quantum or thermal type is of crucial importance [ru

Probing N=2 superconformal field theories with localization

Energy Technology Data Exchange (ETDEWEB)

Fiol, Bartomeu [Departament de Física Fonamental i Institut de Ciències del Cosmos,Universitat de Barcelona,Martí i Franquès 1, 08028 Barcelona, Catalonia (Spain); Garolera, Blai [Escuela de Física, Universidad de Costa Rica,11501-2060 San José (Costa Rica); Torrents, Genís [Departament de Física Fonamental i Institut de Ciències del Cosmos,Universitat de Barcelona,Martí i Franquès 1, 08028 Barcelona, Catalonia (Spain)

2016-01-27

We use supersymmetric localization to study probes of four dimensional Lagrangian N=2 superconformal field theories. We first derive a unique equation for the eigenvalue density of these theories. We observe that these theories have a Wigner eigenvalue density precisely when they satisfy a necessary condition for having a holographic dual with a sensible higher-derivative expansion. We then compute in the saddle-point approximation the vacuum expectation value of 1/2-BPS circular Wilson loops, and the two-point functions of these Wilson loops with the Lagrangian density and with the stress-energy tensor. This last computation also provides the corresponding Bremsstrahlung functions and entanglement entropies. As expected, whenever a finite fraction of the matter is in the fundamental representation, the results are drastically different from those of N=4 supersymmetric Yang-Mills theory.

The Correlation between Game Theory and International Trade

Directory of Open Access Journals (Sweden)

Simona-Valeria TOMA

2012-08-01

Full Text Available The Correlation between Game Theory and International TradeAbstract:Game theory, in its most basic form, considers two or more players and analyses the different strategies that they can use and the effect that these strategies will have on each player. International trade allows countries to use better their resources (labor, technology or capital. Since countries have different capital or natural resources, some of them will produce a good more efficiently than others and therefore could sell it cheaper than other countries. By using game theory in international trade we could determine if the Heckscher-Ohlin-Samuelson model is correct and what would be the best specialization for each country. The aim of this paper is to test if game theory could be successfully used in a thorough analysis of international trade specialization.

Construction of exchange-correlation functionals through interpolation between the non-interacting and the strong-correlation limit

International Nuclear Information System (INIS)

Zhou, Yongxi; Ernzerhof, Matthias; Bahmann, Hilke

2015-01-01

Drawing on the adiabatic connection of density functional theory, exchange-correlation functionals of Kohn-Sham density functional theory are constructed which interpolate between the extreme limits of the electron-electron interaction strength. The first limit is the non-interacting one, where there is only exchange. The second limit is the strong correlated one, characterized as the minimum of the electron-electron repulsion energy. The exchange-correlation energy in the strong-correlation limit is approximated through a model for the exchange-correlation hole that is referred to as nonlocal-radius model [L. O. Wagner and P. Gori-Giorgi, Phys. Rev. A 90, 052512 (2014)]. Using the non-interacting and strong-correlated extremes, various interpolation schemes are presented that yield new approximations to the adiabatic connection and thus to the exchange-correlation energy. Some of them rely on empiricism while others do not. Several of the proposed approximations yield the exact exchange-correlation energy for one-electron systems where local and semi-local approximations often fail badly. Other proposed approximations generalize existing global hybrids by using a fraction of the exchange-correlation energy in the strong-correlation limit to replace an equal fraction of the semi-local approximation to the exchange-correlation energy in the strong-correlation limit. The performance of the proposed approximations is evaluated for molecular atomization energies, total atomic energies, and ionization potentials

Quantum field theory with infinite component local fields as an alternative to the string theories

Science.gov (United States)

Krasnikov, N. V.

1987-09-01

We show that the introduction of the infinite component local fields with higher-order derivatives in the interaction makes the theory completely ultraviolet finite. For the γ5-anomalous theories the introduction of the infinite component field makes the theory renormalizable or even superrenormalizable. I am indebted to J. Ambjōrn, P. Di Vecchia, H.B. Nielsen and L. Rozhansky for useful discussions. It is a pleasure to thank the Niels Bohr Institute (Copenhagen) where this work was completed for kind hospitality.

Quantal density functional theory. 2. ed.

International Nuclear Information System (INIS)

Sahni, Viraht

2016-01-01

This book is on quantal density functional theory (QDFT) which is a time-dependent local effective potential theory of the electronic structure of matter. The time-independent QDFT constitutes a special case. The 2 nd edition describes the further development of the theory, and extends it to include the presence of an external magnetostatic field. The theory is based on the 'quantal Newtonian' second and first laws for the individual electron. These laws are in terms of 'classical' fields that pervade all space, and their quantal sources. The fields are separately representative of the electron correlations that must be accounted for in local potential theory. Recent developments show that irrespective of the type of external field the electrons are subject to, the only correlations beyond those due to the Pauli exclusion principle and Coulomb repulsion that need be considered are solely of the correlation-kinetic effects. Foundational to QDFT, the book describes Schroedinger theory from the new perspective of the single electron in terms of the 'quantal Newtonian' laws. Hohenberg-Kohn density functional theory (DFT), new understandings of the theory and its extension to the presence of an external uniform magnetostatic field are described. The physical interpretation via QDFT, in terms of electron correlations, of Kohn-Sham DFT, approximations to it and Slater theory are provided.

Quantal density functional theory. 2. ed.

Energy Technology Data Exchange (ETDEWEB)

Sahni, Viraht

2016-07-01

This book is on quantal density functional theory (QDFT) which is a time-dependent local effective potential theory of the electronic structure of matter. The time-independent QDFT constitutes a special case. The 2{sup nd} edition describes the further development of the theory, and extends it to include the presence of an external magnetostatic field. The theory is based on the 'quantal Newtonian' second and first laws for the individual electron. These laws are in terms of 'classical' fields that pervade all space, and their quantal sources. The fields are separately representative of the electron correlations that must be accounted for in local potential theory. Recent developments show that irrespective of the type of external field the electrons are subject to, the only correlations beyond those due to the Pauli exclusion principle and Coulomb repulsion that need be considered are solely of the correlation-kinetic effects. Foundational to QDFT, the book describes Schroedinger theory from the new perspective of the single electron in terms of the 'quantal Newtonian' laws. Hohenberg-Kohn density functional theory (DFT), new understandings of the theory and its extension to the presence of an external uniform magnetostatic field are described. The physical interpretation via QDFT, in terms of electron correlations, of Kohn-Sham DFT, approximations to it and Slater theory are provided.

Correlators of Ramond-Neveu-Schwarz fields in string theory

Energy Technology Data Exchange (ETDEWEB)

Haertl, Daniel

2011-07-15

In this thesis we provide calculational tools in order to calculate scattering amplitudes in string theory at tree- and loop-level. In particular, we discuss the calculation of correlation functions consisting of Ramond-Neveu-Schwarz fields in four, six, eight and ten space-time dimensions and calculate the amplitude involving two gauge fields and four gauginos at tree-level. Multi-parton superstring amplitudes are of considerable theoretical interest in the frame-work of a full-fledged superstring theory and of phenomenological interest in describing corrections to four-dimensional scattering processes. The Neveu-Schwarz fermions and Ramond spin fields enter the scattering amplitudes through vertex operators of bosonic and fermionic string states and determine the Lorentz structure of the total amplitude. Due to their interacting nature their correlators cannot be evaluated using Wick's theorem but must be calculated from first principles. At tree-level such correlation functions can be determined by analyzing their Lorentz and singularity structure. In four space-time dimensions we show how to calculate Ramond- Neveu-Schwarz correlators with any number of fields. This method is based on factorizing the expressions into correlators involving only left- or right-handed spin fields and calculating these functions. This factorization property does not hold in higher dimensions. Nevertheless, we are able to calculate certain classes of correlators with arbitrary many fields. Additionally, in eight dimensions we can profit from SO(8) triality to derive further tree-level correlation functions. Ramond-Neveu-Schwarz correlators at loop-level can be evaluated by re-expressing the fermions and spin fields in terms of SO(2) spin system operators. Using this method we present expressions for all correlators up to six-point level and show in addition results for certain classes of correlators with any number of fields. Our findings hold for string scattering at arbitrary

Correlators of Ramond-Neveu-Schwarz fields in string theory

International Nuclear Information System (INIS)

Haertl, Daniel

2011-01-01

In this thesis we provide calculational tools in order to calculate scattering amplitudes in string theory at tree- and loop-level. In particular, we discuss the calculation of correlation functions consisting of Ramond-Neveu-Schwarz fields in four, six, eight and ten space-time dimensions and calculate the amplitude involving two gauge fields and four gauginos at tree-level. Multi-parton superstring amplitudes are of considerable theoretical interest in the frame-work of a full-fledged superstring theory and of phenomenological interest in describing corrections to four-dimensional scattering processes. The Neveu-Schwarz fermions and Ramond spin fields enter the scattering amplitudes through vertex operators of bosonic and fermionic string states and determine the Lorentz structure of the total amplitude. Due to their interacting nature their correlators cannot be evaluated using Wick's theorem but must be calculated from first principles. At tree-level such correlation functions can be determined by analyzing their Lorentz and singularity structure. In four space-time dimensions we show how to calculate Ramond- Neveu-Schwarz correlators with any number of fields. This method is based on factorizing the expressions into correlators involving only left- or right-handed spin fields and calculating these functions. This factorization property does not hold in higher dimensions. Nevertheless, we are able to calculate certain classes of correlators with arbitrary many fields. Additionally, in eight dimensions we can profit from SO(8) triality to derive further tree-level correlation functions. Ramond-Neveu-Schwarz correlators at loop-level can be evaluated by re-expressing the fermions and spin fields in terms of SO(2) spin system operators. Using this method we present expressions for all correlators up to six-point level and show in addition results for certain classes of correlators with any number of fields. Our findings hold for string scattering at arbitrary loop

Plaquette-plaquette correlations in the SU(2) lattice gauge theory

International Nuclear Information System (INIS)

Berg, B.

1980-09-01

Monte Carlo measurements of plaquette-plaquette correlations in the 4-dimensional SU(2) lattice gauge theory are reported. For low temperatures the glue ball mass (= inverse correlation length) is estimated to be msub(g) = (3.7 +- 1.2) √K, where K is the string tension. (orig.)

Effect of Ionic Correlations on the Surface Forces in Thin Liquid Films: Influence of Multivalent Coions and Extended Theory

Directory of Open Access Journals (Sweden)

Krassimir D. Danov

2016-03-01

Full Text Available Experimental data for the disjoining pressure of foam films stabilized by anionic surfactant in the presence of 1:1, 1:2, 1:3, and 2:2 electrolytes: NaCl, Na2SO4, Na3Citrate, and MgSO4 are reported. The disjoining pressure predicted by the Derjaguin-Landau-Verwey-Overbeek (DLVO theory coincides with the experimental data in the case of a 1:1 electrolyte, but it is considerably greater than the measured pressure in all other cases. The theory is extended to account for the effects of ionic correlations and finite ionic radii. Original analytical expressions are derived for the local activity coefficient, electrostatic disjoining pressure, and asymptotic screening parameter. With the same parameter of counterion binding as for a 1:1 electrolyte, the curves predicted by the extended theory are in perfect agreement with the experimental data for 1:2 and 1:3 electrolytes. In comparison with the DLVO theory, the effect of ionic correlations leads to more effective screening of electrostatic interactions, and lower electric potential and counterion concentrations in the film’s midplane, resulting in lower disjoining pressure, as experimentally observed. The developed theory is applicable to both multivalent coions and multivalent counterions. Its application could remove some discrepancies between theory and experiment observed in studies with liquid films from electrolyte solutions.

Local versus nonlocal information in quantum-information theory: Formalism and phenomena

International Nuclear Information System (INIS)

Horodecki, Michal; Horodecki, Ryszard; Synak-Radtke, Barbara; Horodecki, Pawel; Oppenheim, Jonathan; Sen, Aditi; Sen, Ujjwal

2005-01-01

In spite of many results in quantum information theory, the complex nature of compound systems is far from clear. In general the information is a mixture of local and nonlocal ('quantum') information. It is important from both pragmatic and theoretical points of view to know the relationships between the two components. To make this point more clear, we develop and investigate the quantum-information processing paradigm in which parties sharing a multipartite state distill local information. The amount of information which is lost because the parties must use a classical communication channel is the deficit. This scheme can be viewed as complementary to the notion of distilling entanglement. After reviewing the paradigm in detail, we show that the upper bound for the deficit is given by the relative entropy distance to so-called pseudoclassically correlated states; the lower bound is the relative entropy of entanglement. This implies, in particular, that any entangled state is informationally nonlocal - i.e., has nonzero deficit. We also apply the paradigm to defining the thermodynamical cost of erasing entanglement. We show the cost is bounded from below by relative entropy of entanglement. We demonstrate the existence of several other nonlocal phenomena which can be found using the paradigm of local information. For example, we prove the existence of a form of nonlocality without entanglement and with distinguishability. We analyze the deficit for several classes of multipartite pure states and obtain that in contrast to the GHZ state, the Aharonov state is extremely nonlocal. We also show that there do not exist states for which the deficit is strictly equal to the whole informational content (bound local information). We discuss the relation of the paradigm with measures of classical correlations introduced earlier. It is also proved that in the one-way scenario, the deficit is additive for Bell diagonal states. We then discuss complementary features of

Non local theory of excitations applied to the Hubbard model

International Nuclear Information System (INIS)

Kakehashi, Y; Nakamura, T; Fulde, P

2010-01-01

We propose a nonlocal theory of single-particle excitations. It is based on an off-diagonal effective medium and the projection operator method for treating the retarded Green function. The theory determines the nonlocal effective medium matrix elements by requiring that they are consistent with those of the self-energy of the Green function. This arrows for a description of long-range intersite correlations with high resolution in momentum space. Numerical study for the half-filled Hubbard model on the simple cubic lattice demonstrates that the theory is applicable to the strong correlation regime as well as the intermediate regime of Coulomb interaction strength. Furthermore the results show that nonlocal excitations cause sub-bands in the strong Coulomb interaction regime due to strong antiferromagnetic correlations, decrease the quasi-particle peak on the Fermi level with increasing Coulomb interaction, and shift the critical Coulomb interaction U C2 for the divergence of effective mass towards higher energies at least by a factor of two as compared with that in the single-site approximation.

Importance of the local constraint in slave-boson theories

International Nuclear Information System (INIS)

Zhang, L.; Jain, J.K.; Emery, V.J.

1993-01-01

Slave bosons are commonly introduced in order to implement an infinite Hubbard U by means of a local constraint. The usual starting point for investigations within this scheme is a mean-field theory in which the constraint is taken to be global. This approximate treatment of the constraint is studied in the context of a two-band Hubbard model, and it is shown that (i) the ground state has a significant number of doubly occupied sites, despite the infinite on-site repulsion in the original model, and (ii) there is an unphysical tendency for pairing. However, it is found that if the local constraint is retained for the insulator at half filling, then mean-field theory gives the correct result that the double occupancy is zero

Theory of many-body localization in periodically driven systems

International Nuclear Information System (INIS)

Abanin, Dmitry A.; De Roeck, Wojciech; Huveneers, François

2016-01-01

We present a theory of periodically driven, many-body localized (MBL) systems. We argue that MBL persists under periodic driving at high enough driving frequency: The Floquet operator (evolution operator over one driving period) can be represented as an exponential of an effective time-independent Hamiltonian, which is a sum of quasi-local terms and is itself fully MBL. We derive this result by constructing a sequence of canonical transformations to remove the time-dependence from the original Hamiltonian. When the driving evolves smoothly in time, the theory can be sharpened by estimating the probability of adiabatic Landau–Zener transitions at many-body level crossings. In all cases, we argue that there is delocalization at sufficiently low frequency. We propose a phase diagram of driven MBL systems.

Extended Møller-Plesset perturbation theory for dynamical and static correlations

International Nuclear Information System (INIS)

Tsuchimochi, Takashi; Van Voorhis, Troy

2014-01-01

We present a novel method that appropriately handles both dynamical and static electron correlations in a balanced manner, using a perturbation theory on a spin-extended Hartree-Fock (EHF) wave function reference. While EHF is a suitable candidate for degenerate systems where static correlation is ubiquitous, it is known that most of dynamical correlation is neglected in EHF. In this work, we derive a perturbative correction to a fully spin-projected self-consistent wave function based on second-order Møller-Plesset perturbation theory (MP2). The proposed method efficiently captures the ability of EHF to describe static correlation in degeneracy, combined with MP2's ability to treat dynamical correlation effects. We demonstrate drastic improvements on molecular ground state and excited state potential energy curves and singlet-triplet splitting energies over both EHF and MP2 with similar computational effort to the latter

Matrix models from localization of five-dimensional supersymmetric noncommutative U(1) gauge theory

International Nuclear Information System (INIS)

Lee, Bum-Hoon; Ro, Daeho; Yang, Hyun Seok

2017-01-01

We study localization of five-dimensional supersymmetric U(1) gauge theory on S 3 ×ℝ θ 2 where ℝ θ 2 is a noncommutative (NC) plane. The theory can be isomorphically mapped to three-dimensional supersymmetric U(N→∞) gauge theory on S 3 using the matrix representation on a separable Hilbert space on which NC fields linearly act. Therefore the NC space ℝ θ 2 allows for a flexible path to derive matrix models via localization from a higher-dimensional supersymmetric NC U(1) gauge theory. The result shows a rich duality between NC U(1) gauge theories and large N matrix models in various dimensions.

Development of Generalized Correlation Equation for the Local Wall Shear Stress

International Nuclear Information System (INIS)

Jeon, Yu Mi; Park, Ju Hwan

2010-06-01

The pressure drop characteristics for a fuel channel are essential for the design and reliable operation of a nuclear reactor. Over several decades, analytical methods have been developed to predict the friction factor in the fuel bundle flows. In order to enhance the accuracy of prediction for the pressure drop in a rod bundle, the influences of a channel wall and the local shear stress distribution should be considered. Therefore, the correlation equation for a local wall shear stress distribution should be developed in order to secure an analytical solution for the friction factor of a rod bundle. For a side subchannel, which has the influence of the channel wall, the local wall shear stress distribution is dependent on the ratio of wall to diameter (W/D) as well as the ratio of pitch to diameter (P/D). In the case that W/D has the same value with P/D, the local shear stress distribution can be simply correlated with the function of angular position for each value of P/D. While in the case where W/D has a different value than P/D, the correlation equation should be developed for each case of P/D and W/D. Therefore, in the present study, the generalized correlation equation of the local wall shear stress distribution was developed for a side subchannel in the case where W/D has a different value than P/D. Consequently, the generalized correlation equation of a local wall shear stress distribution can be represented by the equivalent pitch to diameter ratio, P'/D for the case that P/D and W/D had a different value

Calculations with the quasirelativistic local-spin-density-functional theory for high-Z atoms

International Nuclear Information System (INIS)

Guo, Y.; Whitehead, M.A.

1988-01-01

The generalized-exchange local-spin-density-functional theory (LSD-GX) with relativistic corrections of the mass velocity and Darwin terms has been used to calculate statistical total energies for the neutral atoms, the positive ions, and the negative ions for high-Z elements. The effect of the correlation and relaxation correction on the statistical total energy is discussed. Comparing the calculated results for the ionization potentials and electron affinities for the atoms (atomic number Z from 37 to 56 and 72 to 80) with experiment, shows that for the atoms rubidium to barium both the LSD-GX and the quasirelativistic LSD-GX, with self-interaction correction, Gopinathan, Whitehead, and Bogdanovic's Fermi-hole parameters [Phys. Rev. A 14, 1 (1976)], and Vosko, Wilk, and Nusair's correlation correction [Can. J. Phys. 58, 1200 (1980)], are very good methods for calculating ionization potentials and electron affinities. For the atoms hafnium to mercury the relativistic effect has to be considered

Quantal density functional theory

CERN Document Server

Sahni, Viraht

2016-01-01

This book deals with quantal density functional theory (QDFT) which is a time-dependent local effective potential theory of the electronic structure of matter. The treated time-independent QDFT constitutes a special case. In the 2nd edition, the theory is extended to include the presence of external magnetostatic fields. The theory is a description of matter based on the ‘quantal Newtonian’ first and second laws which is in terms of “classical” fields that pervade all space, and their quantal sources. The fields, which are explicitly defined, are separately representative of electron correlations due to the Pauli exclusion principle, Coulomb repulsion, correlation-kinetic, correlation-current-density, and correlation-magnetic effects. The book further describes Schrödinger theory from the new physical perspective of fields and quantal sources. It also describes traditional Hohenberg-Kohn-Sham DFT, and explains via QDFT the physics underlying the various energy functionals and functional derivatives o...

Beyond Bell's theorem: realism and locality without Bell-type correlations.

Science.gov (United States)

De Zela, F

2017-11-06

The long-lasting view of entanglement as the characteristic trait of quantum mechanics has been recently challenged by experimental demonstrations of non-quantum entanglement. This motivates a review of the meaning of Bell violations, which have been widely taken to prove the impossibility of a realistic interpretation of quantum mechanics and as a manifestation of its non-local character. This work provides new theoretical evidence for the need of reviewing the meaning of Bell violations, especially when they occur outside the quantum framework. We present a local-realistic model that reproduces quantum predictions concerning Bell tests. We claim that local-realism is fully compatible with correlations that are not of the Bell type and therefore lie outside the scope of Bell's theorem. Most experimental Bell tests involve either spin vectors spanning the Bloch sphere or Stokes vectors spanning the Poincaré sphere. A suitable statistical tool that allows assessing correlations between vectors is given by inner-product-type correlations. Using them, it is possible to reproduce quantum predictions for all Bell states, thereby explaining experimental results of Bell tests within a local-realistic framework.

Local structure theory: calculation on hexagonal arrays, and interaction of rule and lattice

International Nuclear Information System (INIS)

Gutowitz, H.A.; Victor, J.D.

1989-01-01

Local structure theory calculations are applied to the study of cellular automata on the two-dimensional hexagonal lattice. A particular hexagonal lattice rule denoted (3422) is considered in detail. This rule has many features in common with Conway's Life. The local structure theory captures many of the statistical properties of this rule; this supports hypotheses raised by a study of Life itself. As in Life, the state of a cell under (3422) depends only on the state of the cell itself and the sum of states in its neighborhood at the previous time step. This property implies that evolution rules which operate in the same way can be studied on different lattices. The differences between the behavior of these rules on different lattices are dramatic. The mean field theory cannot reflect these differences. However, a generalization of the mean field theory, the local structure theory, does account for the rule-lattice interaction

Cardy formula for 4d SUSY theories and localization

Energy Technology Data Exchange (ETDEWEB)

Pietro, Lorenzo Di [Perimeter Institute for Theoretical Physics,Caroline Street N 31, Waterloo (Canada); Department of Particle Physics and Astrophysics, Weizmann Institute of Science,Herzl street 234, Rehovot (Israel); Honda, Masazumi [Department of Particle Physics and Astrophysics, Weizmann Institute of Science,Herzl street 234, Rehovot (Israel)

2017-04-11

We study 4d N=1 supersymmetric theories on a compact Euclidean manifold of the form S{sup 1}×M{sub 3}. Partition functions of gauge theories on this background can be computed using localization, and explicit formulas have been derived for different choices of the compact manifold M{sub 3}. Taking the limit of shrinking S{sup 1}, we present a general formula for the limit of the localization integrand, derived by simple effective theory considerations, generalizing the result of https://www.doi.org/10.1007/JHEP07(2016)025. The limit is given in terms of an effective potential for the holonomies around the S{sup 1}, whose minima determine the asymptotic behavior of the partition function. If the potential is minimized in the origin, where it vanishes, the partition function has a Cardy-like behavior fixed by Tr(R), while a nontrivial minimum gives a shift in the coefficient. In all the examples that we consider, the origin is a minimum if Tr(R)≤0.

Similarity-transformed perturbation theory on top of truncated local coupled cluster solutions: Theory and applications to intermolecular interactions

Energy Technology Data Exchange (ETDEWEB)

Azar, Richard Julian, E-mail: julianazar2323@berkeley.edu; Head-Gordon, Martin, E-mail: mhg@cchem.berkeley.edu [Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2015-05-28

Your correspondents develop and apply fully nonorthogonal, local-reference perturbation theories describing non-covalent interactions. Our formulations are based on a Löwdin partitioning of the similarity-transformed Hamiltonian into a zeroth-order intramonomer piece (taking local CCSD solutions as its zeroth-order eigenfunction) plus a first-order piece coupling the fragments. If considerations are limited to a single molecule, the proposed intermolecular similarity-transformed perturbation theory represents a frozen-orbital variant of the “(2)”-type theories shown to be competitive with CCSD(T) and of similar cost if all terms are retained. Different restrictions on the zeroth- and first-order amplitudes are explored in the context of large-computation tractability and elucidation of non-local effects in the space of singles and doubles. To accurately approximate CCSD intermolecular interaction energies, a quadratically growing number of variables must be included at zeroth-order.

Time-localized wavelet multiple regression and correlation

Science.gov (United States)

Fernández-Macho, Javier

2018-02-01

This paper extends wavelet methodology to handle comovement dynamics of multivariate time series via moving weighted regression on wavelet coefficients. The concept of wavelet local multiple correlation is used to produce one single set of multiscale correlations along time, in contrast with the large number of wavelet correlation maps that need to be compared when using standard pairwise wavelet correlations with rolling windows. Also, the spectral properties of weight functions are investigated and it is argued that some common time windows, such as the usual rectangular rolling window, are not satisfactory on these grounds. The method is illustrated with a multiscale analysis of the comovements of Eurozone stock markets during this century. It is shown how the evolution of the correlation structure in these markets has been far from homogeneous both along time and across timescales featuring an acute divide across timescales at about the quarterly scale. At longer scales, evidence from the long-term correlation structure can be interpreted as stable perfect integration among Euro stock markets. On the other hand, at intramonth and intraweek scales, the short-term correlation structure has been clearly evolving along time, experiencing a sharp increase during financial crises which may be interpreted as evidence of financial 'contagion'.

Multicomponent density functional theory embedding formulation

Energy Technology Data Exchange (ETDEWEB)

Culpitt, Tanner; Brorsen, Kurt R.; Pak, Michael V.; Hammes-Schiffer, Sharon, E-mail: shs3@illinois.edu [Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Ave, Urbana, Illinois 61801 (United States)

2016-07-28

Multicomponent density functional theory (DFT) methods have been developed to treat two types of particles, such as electrons and nuclei, quantum mechanically at the same level. In the nuclear-electronic orbital (NEO) approach, all electrons and select nuclei, typically key protons, are treated quantum mechanically. For multicomponent DFT methods developed within the NEO framework, electron-proton correlation functionals based on explicitly correlated wavefunctions have been designed and used in conjunction with well-established electronic exchange-correlation functionals. Herein a general theory for multicomponent embedded DFT is developed to enable the accurate treatment of larger systems. In the general theory, the total electronic density is separated into two subsystem densities, denoted as regular and special, and different electron-proton correlation functionals are used for these two electronic densities. In the specific implementation, the special electron density is defined in terms of spatially localized Kohn-Sham electronic orbitals, and electron-proton correlation is included only for the special electron density. The electron-proton correlation functional depends on only the special electron density and the proton density, whereas the electronic exchange-correlation functional depends on the total electronic density. This scheme includes the essential electron-proton correlation, which is a relatively local effect, as well as the electronic exchange-correlation for the entire system. This multicomponent DFT-in-DFT embedding theory is applied to the HCN and FHF{sup −} molecules in conjunction with two different electron-proton correlation functionals and three different electronic exchange-correlation functionals. The results illustrate that this approach provides qualitatively accurate nuclear densities in a computationally tractable manner. The general theory is also easily extended to other types of partitioning schemes for multicomponent systems.

Globally and locally supersymmetric effective theories for light fields

CERN Document Server

Brizi, Leonardo; Scrucca, Claudio A

2009-01-01

We reconsider the general question of how to characterize most efficiently the low-energy effective theory obtained by integrating out heavy modes in globally and locally supersymmetric theories. We consider theories with chiral and vector multiplets and identify the conditions under which an approximately supersymmetric low-energy effective theory can exist. These conditions translate into the requirements that all the derivatives, fermions and auxiliary fields should be small in units of the heavy mass scale. They apply not only to the matter sector, but also to the gravitational one if present, and imply in that case that the gravitino mass should be small. We then show how to determine the unique exactly supersymmetric theory that approximates this effective theory at the lowest order in the counting of derivatives, fermions and auxiliary fields, by working both at the superfield level and with component fields. As a result we give a simple prescription for integrating out heavy superfields in an algebrai...

On topological approach to local theory of surfaces in Calabi-Yau threefolds

DEFF Research Database (Denmark)

Gukov, Sergei; Liu, Chiu-Chu Melissa; Sheshmani, Artan

2017-01-01

We study the web of dualities relating various enumerative invariants, notably Gromov-Witten invariants and invariants that arise in topological gauge theory. In particular, we study Donaldson-Thomas gauge theory and its reductions to D=4 and D=2 which are relevant to the local theory of surfaces...

Modular localization and the holistic structure of causal quantum theory, a historical perspective

International Nuclear Information System (INIS)

Schroer, Bert

2014-01-01

Recent insights into the conceptual structure of localization in QFT ('modular localization') led to clarifications of old unsolved problems. The oldest one is the Einstein-Jordan conundrum which led Jordan in 1925 to the discovery of quantum field theory. This comparison of fluctuations in subsystems of heat bath systems (Einstein) with those resulting from the restriction of the QFT vacuum state to an open subvolume (Jordan) leads to a perfect analogy; the globally pure vacuum state becomes upon local restriction a strongly impure KMS state. This phenomenon of localization-caused thermal behavior as well as the vacuum-polarization clouds at the causal boundary of the localization region places localization in QFT into a sharp contrast with quantum mechanics and justifies the attribute 'holstic'. In fact it positions the E-J Gedankenexperiment into the same conceptual category as the cosmological constant problem and the Unruh Gedankenexperiment. The holistic structure of QFT resulting from 'modular localization' also leads to a revision of the conceptual origin of the crucial crossing property which entered particle theory at the time of the bootstrap S-matrix approach but suffered from incorrect use in the S-matrix settings of the dual model and string theory. The new holistic point of view, which strengthens the autonomous aspect of QFT, also comes with new messages for gauge theory by exposing the clash between Hilbert space structure and localization and presenting alternative solutions based on the use of string local fields in Hilbert space. Among other things this leads to a radical reformulation of the Englert-Higgs symmetry breaking mechanism. (author)

δ expansion for local gauge theories. I. A one-dimensional model

International Nuclear Information System (INIS)

Bender, C.M.; Cooper, F.; Milton, K.A.; Moshe, M.; Pinsky, S.S.; Simmons, L.M. Jr.

1992-01-01

The principles of the δ perturbation theory were first proposed in the context of self-interacting scalar quantum field theory. There it was shown how to expand a (φ 2 ) 1+δ theory as a series in powers of δ and how to recover nonperturbative information about a φ 4 field theory from the δ expansion at δ=1. The purpose of this series of papers is to extend the notions of δ perturbation theory from boson theories to theories having a local gauge symmetry. In the case of quantum electrodynamics one introduces the parameter δ by generalizing the minimal coupling terms to bar ψ(∂-ieA) δ ψ and expanding in powers of δ. This interaction preserves local gauge invariance for all δ. While there are enormous benefits in using the δ expansion (obtaining nonperturbative results), gauge theories present new technical difficulties not encountered in self-interacting boson theories because the expression (∂-ieA) δ contains a derivative operator. In the first paper of this series a one-dimensional model whose interaction term has the form bar ψ[d/dt-igφ(t)] δ ψ is considered. The virtue of this model is that it provides a laboratory in which to study fractional powers of derivative operators without the added complexity of γ matrices. In the next paper of this series we consider two-dimensional electrodynamics and show how to calculate the anomaly in the δ expansion

Three-qutrit correlations violate local realism more strongly than those of three qubits

International Nuclear Information System (INIS)

Kaszlikowski, Dagomir; Gosal, Darwin; Ling, E.J.; Oh, C.H.; Kwek, L.C.; Zukowski, Marek

2002-01-01

We present numerical data showing that three-qutrit correlations for a pure state, which is not maximally entangled, violate local realism more strongly than three-qubit correlations. The strength of violation is measured by the minimal amount of noise that must be admixed to the system so that the noisy correlations have a local and realistic model

Development of generalized correlation equation for the local wall shear stress

International Nuclear Information System (INIS)

Jeon, Yu Mi; Bae, Jun Ho; Park, Joo Hwan

2010-01-01

The pressure drop characteristics for a fuel channel are essential for the design and reliable operation of a nuclear reactor. Over several decades, analytical methods have been developed to predict the friction factor in the fuel bundle flows. In order to enhance the accuracy of prediction for the pressure drop in a rod bundle, the influences of a channel wall and the local shear stress distribution should be considered. Hence, the correlation equation for a local shear stress distribution should be developed in order to secure an analytical solution for the friction factor of a rod bundle. For a side subchannel, which has the influence of the channel wall, the local shear stress distribution is dependent on the ratio of wall to diameter (W/D) as well as the ratio of pitch to diameter (P/D). In the case that W/D has the same value with P/D, the local shear stress distribution can be simply correlated with the function of angular position for each value of P/D. While, in the case that W/D has the different value with P/D, the correlation equation should be developed for each case of P/D and W/D. Hence, in the present study, the generalized correlation equation of a local shear stress distribution is developed for a side subchannel in the case that W/D has the different value with P/D

Higher point spin field correlators in D=4 superstring theory

International Nuclear Information System (INIS)

Haertl, D.; Schlotterer, O.; Stieberger, S.

2010-01-01

Calculational tools are provided allowing to determine general tree-level scattering amplitudes for processes involving bosons and fermions in heterotic and superstring theories in four space-time dimensions. We compute higher-point superstring correlators involving massless four-dimensional fermionic and spin fields. In D=4 these correlators boil down to a product of two pure spin field correlators of left- and right-handed spin fields. This observation greatly simplifies the computation of such correlators. The latter are basic ingredients to compute multi-fermion superstring amplitudes in D=4. Their underlying fermionic structure and the fermionic couplings in the effective action are determined by these correlators.

Conductance of finite systems and scaling in localization theory

Science.gov (United States)

Suslov, I. M.

2012-11-01

The conductance of finite systems plays a central role in the scaling theory of localization (Abrahams et al., Phys. Rev. Lett. 42, 673 (1979)). Usually it is defined by the Landauer-type formulas, which remain open the following questions: (a) exclusion of the contact resistance in the many-channel case; (b) correspondence of the Landauer conductance with internal properties of the system; (c) relation with the diffusion coefficient D(ω, q) of an infinite system. The answers to these questions are obtained below in the framework of two approaches: (1) self-consistent theory of localization by Vollhardt and Wölfle, and (2) quantum mechanical analysis based on the shell model. Both approaches lead to the same definition for the conductance of a finite system, closely related to the Thouless definition. In the framework of the self-consistent theory, the relations of finite-size scaling are derived and the Gell-Mann-Low functions β( g) for space dimensions d = 1, 2, 3 are calculated. In contrast to the previous attempt by Vollhardt and Wölfle (1982), the metallic and localized phase are considered from the same standpoint, and the conductance of a finite system has no singularity at the critical point. In the 2D case, the expansion of β( g) in 1/ g coincides with results of the σ-model approach on the two-loop level and depends on the renormalization scheme in higher loops; the use of dimensional regularization for transition to dimension d = 2 + ɛ looks incompatible with the physical essence of the problem. The results are compared with numerical and physical experiments. A situation in higher dimensions and the conditions for observation of the localization law σ(ω) ∝ - iω for conductivity are discussed.

Conductance of finite systems and scaling in localization theory

International Nuclear Information System (INIS)

Suslov, I. M.

2012-01-01

The conductance of finite systems plays a central role in the scaling theory of localization (Abrahams et al., Phys. Rev. Lett. 42, 673 (1979)). Usually it is defined by the Landauer-type formulas, which remain open the following questions: (a) exclusion of the contact resistance in the many-channel case; (b) correspondence of the Landauer conductance with internal properties of the system; (c) relation with the diffusion coefficient D(ω, q) of an infinite system. The answers to these questions are obtained below in the framework of two approaches: (1) self-consistent theory of localization by Vollhardt and Wölfle, and (2) quantum mechanical analysis based on the shell model. Both approaches lead to the same definition for the conductance of a finite system, closely related to the Thouless definition. In the framework of the self-consistent theory, the relations of finite-size scaling are derived and the Gell-Mann-Low functions β(g) for space dimensions d = 1, 2, 3 are calculated. In contrast to the previous attempt by Vollhardt and Wölfle (1982), the metallic and localized phase are considered from the same standpoint, and the conductance of a finite system has no singularity at the critical point. In the 2D case, the expansion of β(g) in 1/g coincides with results of the σ-model approach on the two-loop level and depends on the renormalization scheme in higher loops; the use of dimensional regularization for transition to dimension d = 2 + ε looks incompatible with the physical essence of the problem. The results are compared with numerical and physical experiments. A situation in higher dimensions and the conditions for observation of the localization law σ(ω) ∝ −iω for conductivity are discussed.

Cutoff effects on energy-momentum tensor correlators in lattice gauge theory

International Nuclear Information System (INIS)

Meyer, Harvey B.

2009-01-01

We investigate the discretization errors affecting correlators of the energy-momentum tensor T μν at finite temperature in SU(N c ) gauge theory with the Wilson action and two different discretizations of T μν . We do so by using lattice perturbation theory and non-perturbative Monte-Carlo simulations. These correlators, which are functions of Euclidean time x 0 and spatial momentum p, are the starting point for a lattice study of the transport properties of the gluon plasma. We find that the correlator of the energy ∫d 3 x T 00 has much larger discretization errors than the correlator of momentum ∫d 3 x T 0k . Secondly, the shear and diagonal stress correlators (T 12 and T kk ) require N τ ≥ 8 for the Tx 0 = 1/2 point to be in the scaling region and the cutoff effect to be less than 10%. We then show that their discretization errors on an anisotropic lattice with a σ /a τ = 2 are comparable to those on the isotropic lattice with the same temporal lattice spacing. Finally, we also study finite p correlators.

Non-static local string in Brans–Dicke theory

Indian Academy of Sciences (India)

Abstract. A recent investigation showed that a local gauge string with a phenomenological energy momentum tensor, as prescribed by Vilenkin, is inconsistent in Brans–Dicke theory. In this work it has been shown that such a string is indeed consistent if one introduces time dependences in the metric. A set of solutions of full ...

Correlation and network topologies in global and local stock indices

Science.gov (United States)

Nobi, Ashadun; Lee, Sungmin; Kim, Doo Hwan; Lee, Jae Woo

2014-07-01

We examined how the correlation and network structure of the global indices and local Korean indices have changed during years 2000-2012. The average correlations of the global indices increased with time, while the local indices showed a decreasing trend except for drastic changes during the crises. A significant change in the network topologies was observed due to the financial crises in both markets. The Jaccard similarities identified the change in the market state due to a crisis in both markets. The dynamic change of the Jaccard index can be used as an indicator of systemic risk or precursors of the crisis.

Quasi-local conserved charges in Lorenz-diffeomorphism covariant theory of gravity

Energy Technology Data Exchange (ETDEWEB)

Adami, H.; Setare, M.R. [University of Kurdistan, Department of Science, Sanandaj (Iran, Islamic Republic of)

2016-04-15

In this paper, using the combined Lorenz-diffeomorphism symmetry, we find a general formula for the quasi-local conserved charge of the covariant gravity theories in a first order formalism of gravity. We simplify the general formula for the Lovelock theory of gravity. Afterwards, we apply the obtained formula on BHT gravity to obtain the energy and angular momentum of the rotating OTT black hole solution in the context of this theory. (orig.)

Quasi-local conserved charges in Lorenz-diffeomorphism covariant theory of gravity

Science.gov (United States)

Adami, H.; Setare, M. R.

2016-04-01

In this paper, using the combined Lorenz-diffeomorphism symmetry, we find a general formula for the quasi-local conserved charge of the covariant gravity theories in a first order formalism of gravity. We simplify the general formula for the Lovelock theory of gravity. Afterwards, we apply the obtained formula on BHT gravity to obtain the energy and angular momentum of the rotating OTT black hole solution in the context of this theory.

The space-time operator product expansion in string theory duals of field theories

International Nuclear Information System (INIS)

Aharony, Ofer; Komargodski, Zohar

2008-01-01

We study the operator product expansion (OPE) limit of correlation functions in field theories which possess string theory duals, from the point of view of the string worldsheet. We show how the interesting ('single-trace') terms in the OPE of the field theory arise in this limit from the OPE of the worldsheet theory of the string dual, using a dominant saddle point which appears in computations of worldsheet correlation functions in the space-time OPE limit. The worldsheet OPE generically contains only non-physical operators, but all the non-physical contributions are resummed by the saddle point to a contribution similar to that of a physical operator, which exactly matches the field theory expectations. We verify that the OPE limit of the worldsheet theory does not have any other contributions to the OPE limit of space-time correlation functions. Our discussion is completely general and applies to any local field theory (conformal at high energies) that has a weakly coupled string theory dual (with arbitrary curvature). As a first application, we compare our results to a proposal of R. Gopakumar for the string theory dual of free gauge theories

Locally covariant quantum field theory and the problem of formulating the same physics in all space-times.

Science.gov (United States)

Fewster, Christopher J

2015-08-06

The framework of locally covariant quantum field theory is discussed, motivated in part using 'ignorance principles'. It is shown how theories can be represented by suitable functors, so that physical equivalence of theories may be expressed via natural isomorphisms between the corresponding functors. The inhomogeneous scalar field is used to illustrate the ideas. It is argued that there are two reasonable definitions of the local physical content associated with a locally covariant theory; when these coincide, the theory is said to be dynamically local. The status of the dynamical locality condition is reviewed, as are its applications in relation to (i) the foundational question of what it means for a theory to represent the same physics in different space-times and (ii) a no-go result on the existence of natural states. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Theory of a gauge gravitational field at localization of the Einstein group

International Nuclear Information System (INIS)

Tunyak, V.N.

1985-01-01

Theory of a gauge gravitational field when localizing a group of movements of the Einstein homogeneous static Universe (the R x SO Einstein group (4)) has been formulated. Proceeding from tetrade components of the Einstein Universe the relation between the Riemann metrics and gauge fields of the Einstein group has been established. Metric coherence with torsion transforming to the Kristoffel coherence of the Einstein Universe has been found when switching out gauge fields. It is shown that within the limit of infinite radius of the Einstein Universe curvature the given Einstein-invariant gauge theory transforms to the tetrade gravitation theory with localized triade rotations. Exact solutions in the form of nonsingular cosmological models have been obtained

A formal derivation of the local energy transfer (LET) theory of homogeneous turbulence

Science.gov (United States)

McComb, W. D.; Yoffe, S. R.

2017-09-01

A statistical closure of the Navier-Stokes hierarchy which leads to equations for the two-point, two-time covariance of the velocity field for stationary, homogeneous isotropic turbulence is presented. It is a generalisation of the self-consistent field method due to Edwards (1964) for the stationary, single-time velocity covariance. The probability distribution functional P≤ft[\\mathbf{u},t\\right] is obtained, in the form of a series, from the Liouville equation by means of a perturbation expansion about a Gaussian distribution, which is chosen to give the exact two-point, two-time covariance. The triple moment is calculated in terms of an ensemble-averaged infinitesimal velocity-field propagator, and shown to yield the Edwards result as a special case. The use of a Gaussian zero-order distribution has been found to justify the introduction of a fluctuation-response relation, which is in accord with modern dynamical theories. In a sense this work completes the analogy drawn by Edwards between turbulence and Brownian motion. Originally Edwards had shown that the noise input was determined by the correlation of the velocity field with the externally applied stirring forces but was unable to determine the system response. Now we find that the system response is determined by the correlation of the velocity field with internal quasi-entropic forces. This analysis is valid to all orders of perturbation theory, and allows the recovery of the local energy transfer (LET) theory, which had previously been derived by more heuristical methods. The LET theory is known to be in good agreement with experimental results. It is also unique among two-point statistical closures in displaying an acceptable (i.e. non-Markovian) relationship between the transfer spectrum and the system response, in accordance with experimental results. As a result of the latter property, it is compatible with the Kolmogorov (K41) spectral phenomenology. In memory of Professor Sir Sam Edwards F

A correlated Walks' theory for DNA denaturation

International Nuclear Information System (INIS)

Mejdani, R.

1994-08-01

We have shown that by using a correlated Walks' theory for the lattice gas model on a one-dimensional lattice, we can study, beside the saturation curves obtained before for the enzyme kinetics, also the DNA denaturation process. In the limit of no interactions between sites the equation for melting curves of DNA reduces to the random model equation. Thus our leads naturally to this classical equation in the limiting case. (author). 22 refs, 3 figs

Generalized extended Navier-Stokes theory: correlations in molecular fluids with intrinsic angular momentum.

Science.gov (United States)

Hansen, J S; Daivis, Peter J; Dyre, Jeppe C; Todd, B D; Bruus, Henrik

2013-01-21

The extended Navier-Stokes theory accounts for the coupling between the translational and rotational molecular degrees of freedom. In this paper, we generalize this theory to non-zero frequencies and wavevectors, which enables a new study of spatio-temporal correlation phenomena present in molecular fluids. To discuss these phenomena in detail, molecular dynamics simulations of molecular chlorine are performed for three different state points. In general, the theory captures the behavior for small wavevector and frequencies as expected. For example, in the hydrodynamic regime and for molecular fluids with small moment of inertia like chlorine, the theory predicts that the longitudinal and transverse intrinsic angular velocity correlation functions are almost identical, which is also seen in the molecular dynamics simulations. However, the theory fails at large wavevector and frequencies. To account for the correlations at these scales, we derive a phenomenological expression for the frequency dependent rotational viscosity and wavevector and frequency dependent longitudinal spin viscosity. From this we observe a significant coupling enhancement between the molecular angular velocity and translational velocity for large frequencies in the gas phase; this is not observed for the supercritical fluid and liquid state points.

Importance of non-local electron-positron correlations for positron annihilation characteristics in solids

International Nuclear Information System (INIS)

Rubaszek, A.

2001-01-01

Several methods to describe the electron-positron (e-p) correlation effects are used in calculations of positron annihilation characteristics in solids. The weighted density approximation (WDA), giving rise to the non-local, state-selective e-p correlation functions, is applied to calculate positron annihilation rates and e-p momentum densities in a variety of metals and silicon. The WDA results are compared to the results of other methods such as the independent particle model, local density approximation, generalised gradient approximation, and also to experiments. The importance of non-locality and state-dependence of the e-p correlation functions is discussed. (orig.)

Locally excitatory, globally inhibitory oscillator networks: theory and application to scene segmentation

Science.gov (United States)

Wang, DeLiang; Terman, David

1995-01-01

A novel class of locally excitatory, globally inhibitory oscillator networks (LEGION) is proposed and investigated analytically and by computer simulation. The model of each oscillator corresponds to a standard relaxation oscillator with two time scales. The network exhibits a mechanism of selective gating, whereby an oscillator jumping up to its active phase rapidly recruits the oscillators stimulated by the same pattern, while preventing other oscillators from jumping up. We show analytically that with the selective gating mechanism the network rapidly achieves both synchronization within blocks of oscillators that are stimulated by connected regions and desynchronization between different blocks. Computer simulations demonstrate LEGION's promising ability for segmenting multiple input patterns in real time. This model lays a physical foundation for the oscillatory correlation theory of feature binding, and may provide an effective computational framework for scene segmentation and figure/ground segregation.

Can EPR non-locality be geometrical?

International Nuclear Information System (INIS)

Ne'eman, Y.

1995-01-01

The presence in Quantum Mechanics of non-local correlations is one of the two fundamentally non-intuitive features of that theory. The non-local correlations themselves fall into two classes: EPR and Geometrical. The non-local characteristics of the geometrical type are well-understood and are not suspected of possibly generating acausal features, such as faster-than-light propagation of information. This has especially become true since the emergence of a geometrical treatment for the relevant gauge theories, i.e. Fiber Bundle geometry, in which the quantum non-localities are seen to correspond to pure homotopy considerations. This aspect is reviewed in section 2. Contrary-wise, from its very conception, the EPR situation was felt to be paradoxical. It has been suggested that the non-local features of EPR might also derive from geometrical considerations, like all other non-local characteristics of QM. In[7], one of the authors was able to point out several plausibility arguments for this thesis, emphasizing in particular similarities between the non-local correlations provided by any gauge field theory and those required by the preservation of the quantum numbers of the original EPR state-vector, throughout its spatially-extended mode. The derivation was, however, somewhat incomplete, especially because of the apparent difference between, on the one hand, the closed spatial loops arising in the analysis of the geometrical non-localities, from Aharonov-Bohm and Berry phases to magnetic monopoles and instantons, and on the other hand, in the EPR case, the open line drawn by the positions of the two moving decay products of the disintegrating particle. In what follows, the authors endeavor to remove this obstacle and show that as in all other QM non-localities, EPR is somehow related to closed loops, almost involving homotopy considerations. They develop this view in section 3

Transport through correlated systems with density functional theory.

Science.gov (United States)

Kurth, S; Stefanucci, G

2017-10-18

We present recent advances in density functional theory (DFT) for applications in the field of quantum transport, with particular emphasis on transport through strongly correlated systems. We review the foundations of the popular Landauer-Büttiker(LB)  +  DFT approach. This formalism, when using approximations to the exchange-correlation (xc) potential with steps at integer occupation, correctly captures the Kondo plateau in the zero bias conductance at zero temperature but completely fails to capture the transition to the Coulomb blockade (CB) regime as the temperature increases. To overcome the limitations of LB  +  DFT, the quantum transport problem is treated from a time-dependent (TD) perspective using TDDFT, an exact framework to deal with nonequilibrium situations. The steady-state limit of TDDFT shows that in addition to an xc potential in the junction, there also exists an xc correction to the applied bias. Open shell molecules in the CB regime provide the most striking examples of the importance of the xc bias correction. Using the Anderson model as guidance we estimate these corrections in the limit of zero bias. For the general case we put forward a steady-state DFT which is based on one-to-one correspondence between the pair of basic variables, steady density on and steady current across the junction and the pair local potential on and bias across the junction. Like TDDFT, this framework also leads to both an xc potential in the junction and an xc correction to the bias. Unlike TDDFT, these potentials are independent of history. We highlight the universal features of both xc potential and xc bias corrections for junctions in the CB regime and provide an accurate parametrization for the Anderson model at arbitrary temperatures and interaction strengths, thus providing a unified DFT description for both Kondo and CB regimes and the transition between them.

Segment-scale, force-level theory of mesoscopic dynamic localization and entropic elasticity in entangled chain polymer liquids

Science.gov (United States)

Dell, Zachary E.; Schweizer, Kenneth S.

2017-04-01

We develop a segment-scale, force-based theory for the breakdown of the unentangled Rouse model and subsequent emergence of isotropic mesoscopic localization and entropic elasticity in chain polymer liquids in the absence of ergodicity-restoring anisotropic reptation or activated hopping motion. The theory is formulated in terms of a conformational N-dynamic-order-parameter generalized Langevin equation approach. It is implemented using a universal field-theoretic Gaussian thread model of polymer structure and closed at the level of the chain dynamic second moment matrix. The physical idea is that the isotropic Rouse model fails due to the dynamical emergence, with increasing chain length, of time-persistent intermolecular contacts determined by the combined influence of local uncrossability, long range polymer connectivity, and a self-consistent treatment of chain motion and the dynamic forces that hinder it. For long chain melts, the mesoscopic localization length (identified as the tube diameter) and emergent entropic elasticity predictions are in near quantitative agreement with experiment. Moreover, the onset chain length scales with the semi-dilute crossover concentration with a realistic numerical prefactor. Distinctive novel predictions are made for various off-diagonal correlation functions that quantify the full spatial structure of the dynamically localized polymer conformation. As the local excluded volume constraint and/or intrachain bonding spring are softened to allow chain crossability, the tube diameter is predicted to swell until it reaches the radius-of-gyration at which point mesoscopic localization vanishes in a discontinuous manner. A dynamic phase diagram for such a delocalization transition is constructed, which is qualitatively consistent with simulations and the classical concept of a critical entanglement degree of polymerization.

Existence of local degrees of freedom for higher dimensional pure Chern-Simons theories

International Nuclear Information System (INIS)

Banados, M.; Garay, L.J.; Henneaux, M.

1996-01-01

The canonical structure of higher dimensional pure Chern-Simons theories is analyzed. It is shown that these theories have generically a nonvanishing number of local degrees of freedom, even though they are obtained by means of a topological construction. This number of local degrees of freedom is computed as a function of the spacetime dimension and the dimension of the gauge group. copyright 1996 The American Physical Society

Importance of the correlation contribution for local hybrid functionals: range separation and self-interaction corrections.

Science.gov (United States)

Arbuznikov, Alexei V; Kaupp, Martin

2012-01-07

Local hybrid functionals with their position-dependent exact-exchange admixture are a conceptually simple and promising extension of the concept of a hybrid functional. Local hybrids based on a simple mixing of the local spin density approximation (LSDA) with exact exchange have been shown to be successful for thermochemistry, reaction barriers, and a range of other properties. So far, the combination of this generation of local hybrids with an LSDA correlation functional has been found to give the most favorable results for atomization energies, for a range of local mixing functions (LMFs) governing the exact-exchange admixture. Here, we show that the choice of correlation functional to be used with local hybrid exchange crucially influences the parameterization also of the exchange part as well as the overall performance. A novel ansatz for the correlation part of local hybrids is suggested based on (i) range-separation of LSDA correlation into short-range (SR) and long-range (LR) parts, and (ii) partial or full elimination of the one-electron self-correlation from the SR part. It is shown that such modified correlation functionals allow overall larger exact exchange admixture in thermochemically competitive local hybrids than before. This results in improvements for reaction barriers and for other properties crucially influenced by self-interaction errors, as demonstrated by a number of examples. Based on the range-separation approach, a fresh view on the breakdown of the correlation energy into dynamical and non-dynamical parts is suggested.

Pearson's correlation coefficient in the theory of networks: A comment

OpenAIRE

Ahmed, Zafar; Kumar, Sachin

2018-01-01

In statistics, the Pearson correlation coefficient $r_{x,y}$ determines the degree of linear correlation between two variables and it is known that $-1 \\le r_{x,y} \\le 1$. In the theory of networks, a curious expression proposed in [PRL {\\bf 89} 208701 (2002)] for degree-degree correlation coefficient $r_{j_i,k_i}, i\\in [1,M]$ has been in use. We realize that the suggested form is the conventional Pearson's coefficient for $\\{(j_i,k_i), (k_i,j_i)\\}$ for $2M$ data points and hence it is rightl...

Correlation and network topologies in global and local stock indices

DEFF Research Database (Denmark)

Nobi, A.; Lee, S.; Kim, D. H.

2014-01-01

the crises. A significant change in the network topologies was observed due to the financial crises in both markets. The Jaccard similarities identified the change in the market state due to a crisis in both markets. The dynamic change of the Jaccard index can be used as an indicator of systemic risk......We examined how the correlation and network structure of the global indices and local Korean indices have changed during years 2000-2012. The average correlations of the global indices increased with time, while the local indices showed a decreasing trend except for drastic changes during...... or precursors of the crisis. (C) 2014 Elsevier B.V. All rights reserved....

Spontaneous symmetry breaking in local gauge quantum field theory; the Higgs mechanism

International Nuclear Information System (INIS)

Strocchi, F.

1977-01-01

Spontaneous symmetry breakings in indefinite metric quantum field theories are analyzed and a generalization of the Goldstone theorem is proved. The case of local gauge quantum field theories is discussed in detail and a characterization is given of the occurrence of the Higgs mechanism versus the Goldstone mechanism. The Higgs phenomenon is explained on general grounds without the introduction of the so-called Higgs fields. The basic property is the relation between the local internal symmetry group and the local group of gauge transformations of the second kind. Spontaneous symmetry breaking of c-number gauge transformations of the second kind is shown to always occur if there are charged local fields. The implications about the absence of mass gap in the Wightman functions and the occurrence of massless particles associated with the unbroken generators in the Higgs phenomenon are discussed. (orig.) [de

Study of local correlations of magnetic and multiferroic compounds

CERN Multimedia

Alves, E J

We propose to study magnetic and multiferroic strongly correlated electron materials using radioactive nuclear probe techniques, at ISOLDE . Following the strategy of a previous project, IS390, our aim is to provide local and element selective information on some of the mechanisms that rule structural, charge and orbital correlations, electronic and magnetic interactions and the coupling of the associated degrees of freedom. The main technique used is Perturbed Angular Correlations (PAC), which allows combined magnetic and electric hyperfine studies. This study is complemented by the use of conventional characterisation techniques, and the investigation of relevant macroscopic properties.

Correlation functions of Coulomb branch operators

Energy Technology Data Exchange (ETDEWEB)

Gerchkovitz, Efrat [Weizmann Institute of Science,Rehovot 76100 (Israel); Gomis, Jaume [Perimeter Institute for Theoretical Physics,Waterloo, ON N2L 2Y5 (Canada); Ishtiaque, Nafiz [Perimeter Institute for Theoretical Physics,Waterloo, ON N2L 2Y5 (Canada); Department of Physics, University of Waterloo,Waterloo, ON N2L 3G1 (Canada); Karasik, Avner; Komargodski, Zohar [Weizmann Institute of Science,Rehovot 76100 (Israel); Pufu, Silviu S. [Joseph Henry Laboratories, Princeton University,Princeton, NJ 08544 (United States)

2017-01-24

We consider the correlation functions of Coulomb branch operators in four-dimensional N=2 Superconformal Field Theories (SCFTs) involving exactly one anti-chiral operator. These extremal correlators are the “minimal' non-holomorphic local observables in the theory. We show that they can be expressed in terms of certain determinants of derivatives of the four-sphere partition function of an appropriate deformation of the SCFT. This relation between the extremal correlators and the deformed four-sphere partition function is non-trivial due to the presence of conformal anomalies, which lead to operator mixing on the sphere. Evaluating the deformed four-sphere partition function using supersymmetric localization, we compute the extremal correlators explicitly in many interesting examples. Additionally, the representation of the extremal correlators mentioned above leads to a system of integrable differential equations. We compare our exact results with previous perturbative computations and with the four-dimensional tt{sup ∗} equations. We also use our results to study some of the asymptotic properties of the perturbative series expansions we obtain in N=2 SQCD.

Alternative separation of exchange and correlation energies in multi-configuration range-separated density-functional theory.

Science.gov (United States)

Stoyanova, Alexandrina; Teale, Andrew M; Toulouse, Julien; Helgaker, Trygve; Fromager, Emmanuel

2013-10-07

The alternative separation of exchange and correlation energies proposed by Toulouse et al. [Theor. Chem. Acc. 114, 305 (2005)] is explored in the context of multi-configuration range-separated density-functional theory. The new decomposition of the short-range exchange-correlation energy relies on the auxiliary long-range interacting wavefunction rather than the Kohn-Sham (KS) determinant. The advantage, relative to the traditional KS decomposition, is that the wavefunction part of the energy is now computed with the regular (fully interacting) Hamiltonian. One potential drawback is that, because of double counting, the wavefunction used to compute the energy cannot be obtained by minimizing the energy expression with respect to the wavefunction parameters. The problem is overcome by using short-range optimized effective potentials (OEPs). The resulting combination of OEP techniques with wavefunction theory has been investigated in this work, at the Hartree-Fock (HF) and multi-configuration self-consistent-field (MCSCF) levels. In the HF case, an analytical expression for the energy gradient has been derived and implemented. Calculations have been performed within the short-range local density approximation on H2, N2, Li2, and H2O. Significant improvements in binding energies are obtained with the new decomposition of the short-range energy. The importance of optimizing the short-range OEP at the MCSCF level when static correlation becomes significant has also been demonstrated for H2, using a finite-difference gradient. The implementation of the analytical gradient for MCSCF wavefunctions is currently in progress.

Local field theory on κ-Minkowski space, star products and noncommutative translations

International Nuclear Information System (INIS)

Kosinski, P.; Maslanka, P.; Lukierski, J.

2000-01-01

We consider local field theory on κ-deformed Minkowski space which is an example of solvable Lie-algebraic noncommutative structure. Using integration formula over κ-Minkowski space and κ-deformed Fourier transform, we consider for deformed local fields the reality conditions as well as deformation of action functionals in standard Minkowski space. We present explicit formulas for two equivalent star products describing CBH quantization of field theory on κ-Minkowski space. We express also via star product technique the noncommutative translations in κ-Minkowski space by commutative translations in standard Minkowski space. (author)

Neuropsychological correlates of theory of mind in patients with early Parkinson's disease.

Science.gov (United States)

Santangelo, Gabriella; Vitale, Carmine; Trojano, Luigi; Errico, Domenico; Amboni, Marianna; Barbarulo, Anna Maria; Grossi, Dario; Barone, Paolo

2012-01-01

The theory of mind is the ability to attribute mental states to oneself and others and to understand that others have beliefs, desires and intentions different from one's own. The aim of the study was to explore the neuropsychological correlates of theory of mind in patients affected by early Parkinson's disease (PD). Thirty-three PD patients and 33 age-, sex-, and education-matched control subjects underwent the Frontal Assessment Battery, as well as tasks assessing "cognitive" and "affective" theory of mind, and memory abilities; questionnaires evaluating behavioral disorders and quality of life were also administrated. Although the 2 groups did not differ on neuropsychological tasks, PD patients' performance on tasks assessing cognitive and affective theory of mind was significantly worse than controls. Moreover, PD patients had more behavioral disorders and worse quality of life than controls. After covarying for behavioral and quality of life scores, the differences between patients and controls on theory of mind tasks remained significant. "Cognitive" theory of mind was associated with Frontal Assessment Battery score and 2 domains of quality of life scale, whereas "affective" theory of mind scores correlated only with behavioral scales such as the Frontal Behavioral Inventory and Apathy Evaluation Scale. The results demonstrate that both affective and cognitive aspects of theory of mind are simultaneously impaired in early PD and suggest that deficits in the 2 subcomponents of theory of mind may be linked to dysfunction of different frontosubcortical circuitries in early PD. Copyright © 2011 Movement Disorder Society.

Can Single-Reference Coupled Cluster Theory Describe Static Correlation?

Science.gov (United States)

Bulik, Ireneusz W; Henderson, Thomas M; Scuseria, Gustavo E

2015-07-14

While restricted single-reference coupled cluster theory truncated to singles and doubles (CCSD) provides very accurate results for weakly correlated systems, it usually fails in the presence of static or strong correlation. This failure is generally attributed to the qualitative breakdown of the reference, and can accordingly be corrected by using a multideterminant reference, including higher-body cluster operators in the ansatz, or allowing symmetry breaking in the reference. None of these solutions are ideal; multireference coupled cluster is not black box, including higher-body cluster operators is computationally demanding, and allowing symmetry breaking leads to the loss of good quantum numbers. It has long been recognized that quasidegeneracies can instead be treated by modifying the coupled cluster ansatz. The recently introduced pair coupled cluster doubles (pCCD) approach is one such example which avoids catastrophic failures and accurately models strong correlations in a symmetry-adapted framework. Here, we generalize pCCD to a singlet-paired coupled cluster model (CCD0) intermediate between coupled cluster doubles and pCCD, yielding a method that possesses the invariances of the former and much of the stability of the latter. Moreover, CCD0 retains the full structure of coupled cluster theory, including a fermionic wave function, antisymmetric cluster amplitudes, and well-defined response equations and density matrices.

Multireference second order perturbation theory with a simplified treatment of dynamical correlation.

Science.gov (United States)

Xu, Enhua; Zhao, Dongbo; Li, Shuhua

2015-10-13

A multireference second order perturbation theory based on a complete active space configuration interaction (CASCI) function or density matrix renormalized group (DMRG) function has been proposed. This method may be considered as an approximation to the CAS/A approach with the same reference, in which the dynamical correlation is simplified with blocked correlated second order perturbation theory based on the generalized valence bond (GVB) reference (GVB-BCPT2). This method, denoted as CASCI-BCPT2/GVB or DMRG-BCPT2/GVB, is size consistent and has a similar computational cost as the conventional second order perturbation theory (MP2). We have applied it to investigate a number of problems of chemical interest. These problems include bond-breaking potential energy surfaces in four molecules, the spectroscopic constants of six diatomic molecules, the reaction barrier for the automerization of cyclobutadiene, and the energy difference between the monocyclic and bicyclic forms of 2,6-pyridyne. Our test applications demonstrate that CASCI-BCPT2/GVB can provide comparable results with CASPT2 (second order perturbation theory based on the complete active space self-consistent-field wave function) for systems under study. Furthermore, the DMRG-BCPT2/GVB method is applicable to treat strongly correlated systems with large active spaces, which are beyond the capability of CASPT2.

Quantum entanglement in non-local games, graph parameters and zero-error information theory

NARCIS (Netherlands)

Scarpa, G.

2013-01-01

We study quantum entanglement and some of its applications in graph theory and zero-error information theory. In Chapter 1 we introduce entanglement and other fundamental concepts of quantum theory. In Chapter 2 we address the question of how much quantum correlations generated by entanglement can

Cosmological term in general relativity theory and localization of de Sitter and Einstein groups

International Nuclear Information System (INIS)

Tunyak, V.N.

1984-01-01

The theory of gauge gravitational field with the de Sitter group localization is formulated. proceeding from the de Sitter Universe tetrad components the relationship between Riemann metrics and de Sitter gauge field is established. It is shown that General relativity theory (GRT) with a cosmological term is the simplest variant of the de Sitter gauge gravitation theory passing in the limit of infinite curvature radius of the de Sitter Universe into the Poincare - invariant GRT without cosmological term. Similarly the theory of gauge gravitational field at localization of the dynamical group of the Einstein homogeneous static Universe (Einstein group RxSO(4)) is formulated

Four-point correlation function of stress-energy tensors in N=4 superconformal theories

CERN Document Server

Korchemsky, G P

2015-01-01

We derive the explicit expression for the four-point correlation function of stress-energy tensors in four-dimensional N=4 superconformal theory. We show that it has a remarkably simple and suggestive form allowing us to predict a large class of four-point correlation functions involving the stress-energy tensor and other conserved currents. We then apply the obtained results on the correlation functions to computing the energy-energy correlations, which measure the flow of energy in the final states created from the vacuum by a source. We demonstrate that they are given by a universal function independent of the choice of the source. Our analysis relies only on N=4 superconformal symmetry and does not use the dynamics of the theory.

Communication: A Jastrow factor coupled cluster theory for weak and strong electron correlation

International Nuclear Information System (INIS)

Neuscamman, Eric

2013-01-01

We present a Jastrow-factor-inspired variant of coupled cluster theory that accurately describes both weak and strong electron correlation. Compatibility with quantum Monte Carlo allows for variational energy evaluations and an antisymmetric geminal power reference, two features not present in traditional coupled cluster that facilitate a nearly exact description of the strong electron correlations in minimal-basis N 2 bond breaking. In double-ζ treatments of the HF and H 2 O bond dissociations, where both weak and strong correlations are important, this polynomial cost method proves more accurate than either traditional coupled cluster or complete active space perturbation theory. These preliminary successes suggest a deep connection between the ways in which cluster operators and Jastrow factors encode correlation

Novel Approaches to Spectral Properties of Correlated Electron Materials: From Generalized Kohn-Sham Theory to Screened Exchange Dynamical Mean Field Theory

Science.gov (United States)

Delange, Pascal; Backes, Steffen; van Roekeghem, Ambroise; Pourovskii, Leonid; Jiang, Hong; Biermann, Silke

2018-04-01

The most intriguing properties of emergent materials are typically consequences of highly correlated quantum states of their electronic degrees of freedom. Describing those materials from first principles remains a challenge for modern condensed matter theory. Here, we review, apply and discuss novel approaches to spectral properties of correlated electron materials, assessing current day predictive capabilities of electronic structure calculations. In particular, we focus on the recent Screened Exchange Dynamical Mean-Field Theory scheme and its relation to generalized Kohn-Sham Theory. These concepts are illustrated on the transition metal pnictide BaCo2As2 and elemental zinc and cadmium.

Extractable Work from Correlations

Directory of Open Access Journals (Sweden)

Martí Perarnau-Llobet

2015-10-01

Full Text Available Work and quantum correlations are two fundamental resources in thermodynamics and quantum information theory. In this work, we study how to use correlations among quantum systems to optimally store work. We analyze this question for isolated quantum ensembles, where the work can be naturally divided into two contributions: a local contribution from each system and a global contribution originating from correlations among systems. We focus on the latter and consider quantum systems that are locally thermal, thus from which any extractable work can only come from correlations. We compute the maximum extractable work for general entangled states, separable states, and states with fixed entropy. Our results show that while entanglement gives an advantage for small quantum ensembles, this gain vanishes for a large number of systems.

Non-Kähler resolved conifold, localized fluxes in M-theory and supersymmetry

International Nuclear Information System (INIS)

Dasgupta, Keshav; Emelin, Maxim; McDonough, Evan

2015-01-01

The known supergravity solution for wrapped D5-branes on the two-cycle of a Kähler resolved conifold is in general ISD but not supersymmetric, with the supersymmetry being broken by the presence of (1, 2) fluxes. However if we allow a non-Kähler metric on the resolved conifold, supersymmetry can easily be restored. The vanishing of the (1, 2) fluxes here corresponds to, under certain conformal rescalings of the metric, the torsion class constraints. We construct a class of explicit non-Kähler metrics on the resolved conifold satisfying the constraints. All this can also be studied from M-theory, where the fluxes and branes become non-localized G-fluxes on deformed Taub-NUT spaces. Interestingly, the gauge fluctuations on the wrapped D5-branes appear now as localized G-fluxes in M-theory. These localized fluxes are related to certain harmonic two-forms that are normalizable. We compute these forms explicitly and discuss how new constraints on the geometry of the non-Kähler manifolds may appear from M-theory considerations.

Quantal density functional theory II. Approximation methods and applications

International Nuclear Information System (INIS)

Sahni, Viraht

2010-01-01

This book is on approximation methods and applications of Quantal Density Functional Theory (QDFT), a new local effective-potential-energy theory of electronic structure. What distinguishes the theory from traditional density functional theory is that the electron correlations due to the Pauli exclusion principle, Coulomb repulsion, and the correlation contribution to the kinetic energy -- the Correlation-Kinetic effects -- are separately and explicitly defined. As such it is possible to study each property of interest as a function of the different electron correlations. Approximations methods based on the incorporation of different electron correlations, as well as a many-body perturbation theory within the context of QDFT, are developed. The applications are to the few-electron inhomogeneous electron gas systems in atoms and molecules, as well as to the many-electron inhomogeneity at metallic surfaces. (orig.)

GOVERNANCE FROM BELOW A Theory of Local Government With Two Empirical Tests

OpenAIRE

Jean-Paul Faguet

2005-01-01

I examine decentralization through the lens of the local dynamics that it unleashes. The national effects of decentralization are simply the sum of its local-level effects. Hence to understand decentralization we must first understand how local government works. This paper proposes a theory of local government as the confluence of two quasi-markets and one organizational dynamic. Good government results when these three elements - political, economic and civil - are in rough balance, and acto...

A technical basis for the flux corrected local conditions critical heat flux correlation

International Nuclear Information System (INIS)

Luxat, J.C.

2008-01-01

The so-called 'flux-corrected' local conditions CHF correlation was developed at Ontario Hydro in the 1980's and was demonstrated to successfully correlate the Onset of Intermittent Dryout (OID) CHF data for 37-element fuel with a downstream-skewed axial heat flux distribution. However, because the heat flux correction factor appeared to be an ad-hoc, albeit a successful modifying factor in the correlation, there was reluctance to accept the correlation more generally. This paper presents a thermalhydraulic basis, derived from two-phase flow considerations, that supports the appropriateness of the heat flux correction as a local effects modifying factor. (author)

Effect of superconducting correlation on the localization of quasiparticles in low dimensions

International Nuclear Information System (INIS)

Xiang, T.

1995-01-01

Localization lengths of superconducting quasiparticles λ s are evaluated and compared with the corresponding normal-state values λ n in one-dimensional (1D) and two-dimensional lattices. The effect of superconducting correlation on the localization of quasiparticles is generally stronger in an off-site pairing state than in an on-site pairing state. The modification of superconducting correlation to λ is strongly correlated with the density of states (DOS) of superconducting quasiparticles. λ s drops within the energy gap but is largely enhanced around energies where DOS peaks appear. For a gapless pairing state in 1D or a d-wave pairing state in 2D, λ s /λ n at the Fermi energy E F is of order 1 and determined purely by the value of gap parameter not by the random potential. For the d-wave pairing state, the localization effect is largely weakened compared with the corresponding normal state and quasiparticles with energies close to E F are more strongly localized than other low-energy quasiparticles

Testing locality at colliders via Bell's inequality?

International Nuclear Information System (INIS)

Abel, S.A.; Dreiner, H.; Dittmar, M.

1992-01-01

We consider a measurement of correlated spins at LEP and show that it does not constitute a general test of local-realistic theories via Bell's inequality. The central point of the argument is that such tests, where the spins of two particles are inferred from a scattering distribution, can be described by a local hidden variable theory. We conclude that with present experimental techniques it is not possible to test locality via Bell's inequality at a collider experiment. Finally we suggest an improved fixed-target experiment as a viable test of Bell's inequality. (orig.)

Maximal locality and predictive power in higher-dimensional, compactified field theories

International Nuclear Information System (INIS)

Kubo, Jisuke; Nunami, Masanori

2004-01-01

To realize maximal locality in a trivial field theory, we maximize the ultraviolet cutoff of the theory by fine tuning the infrared values of the parameters. This optimization procedure is applied to the scalar theory in D + 1 dimensional (D ≥ 4) with one extra dimension compactified on a circle of radius R. The optimized, infrared values of the parameters are then compared with the corresponding ones of the uncompactified theory in D dimensions, which is assumed to be the low-energy effective theory. We find that these values approximately agree with each other as long as R -1 > approx sM is satisfied, where s ≅ 10, 50, 50, 100 for D = 4,5,6,7, and M is a typical scale of the D-dimensional theory. This result supports the previously made claim that the maximization of the ultraviolet cutoff in a nonrenormalizable field theory can give the theory more predictive power. (author)

Differentiability in density-functional theory: Further study of the locality theorem

International Nuclear Information System (INIS)

Lindgren, Ingvar; Salomonson, Sten

2004-01-01

The locality theorem in density-functional theory (DFT) states that the functional derivative of the Hohenberg-Kohn universal functional can be expressed as a local multiplicative potential function, and this is the basis of DFT and of the successful Kohn-Sham model. Nesbet has in several papers [Phys. Rev. A 58, R12 (1998); ibid.65, 010502 (2001); Adv. Quant. Chem, 43, 1 (2003)] claimed that this theorem is in conflict with fundamental quantum physics, and as a consequence that the Hohenberg-Kohn theory cannot be generally valid. We have commented upon these works [Comment, Phys. Rev. A 67, 056501 (2003)] and recently extended the arguments [Adv. Quantum Chem. 43, 95 (2003)]. We have shown that there is no such conflict and that the locality theorem is inherently exact. In the present work we have furthermore verified this numerically by constructing a local Kohn-Sham potential for the 1s2s 3 S state of helium that generates the many-body electron density and shown that the corresponding 2s Kohn-Sham orbital eigenvalue agrees with the ionization energy to nine digits. Similar result is obtained with the Hartree-Fock density. Therefore, in addition to verifying the locality theorem, this result also confirms the so-called ionization-potential theorem

Bleed-through correction for rendering and correlation analysis in multi-colour localization microscopy

International Nuclear Information System (INIS)

Kim, Dahan; Curthoys, Nikki M; Parent, Matthew T; Hess, Samuel T

2013-01-01

Multi-colour localization microscopy has enabled sub-diffraction studies of colocalization between multiple biological species and quantification of their correlation at length scales previously inaccessible with conventional fluorescence microscopy. However, bleed-through, or misidentification of probe species, creates false colocalization and artificially increases certain types of correlation between two imaged species, affecting the reliability of information provided by colocalization and quantified correlation. Despite the potential risk of these artefacts of bleed-through, neither the effect of bleed-through on correlation nor methods for its correction in correlation analyses have been systematically studied at typical rates of bleed-through reported to affect multi-colour imaging. Here, we present a reliable method of bleed-through correction applicable to image rendering and correlation analysis of multi-colour localization microscopy. Application of our bleed-through correction shows that our method accurately corrects the artificial increase in both types of correlation studied (Pearson coefficient and pair correlation), at all rates of bleed-through tested, in all types of correlation examined. In particular, anti-correlation could not be quantified without our bleed-through correction, even at rates of bleed-through as low as 2%. While it is demonstrated with dichroic-based multi-colour FPALM here, our presented method of bleed-through correction can be applied to all types of localization microscopy (PALM, STORM, dSTORM, GSDIM, etc), including both simultaneous and sequential multi-colour modalities, provided the rate of bleed-through can be reliably determined. (special issue article)

Hanbury Brown and Twiss correlations of Anderson localized waves

International Nuclear Information System (INIS)

Lahini, Y.; Bromberg, Y.; Silberberg, Y.; Shechtman, Y.; Szameit, A.; Christodoulides, D. N.; Morandotti, R.

2011-01-01

When light waves propagate through disordered photonic lattices, they can eventually become localized due to multiple scattering effects. Here we show experimentally that while the evolution and localization of the photon density distribution is similar in the two cases of diagonal and off-diagonal disorder, the density-density correlation carries a distinct signature of the type of disorder. We show that these differences reflect a symmetry in the spectrum and eigenmodes that exists in off-diagonally disordered lattices but is absent in lattices with diagonal disorder.

A local dynamic correlation function from inelastic neutron scattering

International Nuclear Information System (INIS)

McQueeney, R.J.

1997-01-01

Information about local and dynamic atomic correlations can be obtained from inelastic neutron scattering measurements by Fourier transform of the Q-dependent intensity oscillations at a particular frequency. A local dynamic structure function, S(r,ω), is defined from the dynamic scattering function, S(Q,ω), such that the elastic and frequency-integrated limits correspond to the average and instantaneous pair-distribution functions, respectively. As an example, S(r,ω) is calculated for polycrystalline aluminum in a model where atomic motions are entirely due to harmonic phonons

Relativistic local quantum field theory for m=0 particles

International Nuclear Information System (INIS)

Morales Villasevil, A.

1965-01-01

A method is introduced ta deal with relativistic quantum field theory for particles with m=0. Two mappings I and J, giving rise respectively to particle and anti particle states, are defined between a test space and the physical Hilbert space. The intrinsic field operator is then defined as the minimal causal linear combinations of operators belonging to the annihilation-creation algebra associated to the germ and antigerm parts of the element. Local elements are introduced as improper test elements and local field operators are constructed in the same way as the intrinsic ones. Commutation rules are given. (Author) 17 refs

Global solutions of restricted open-shell Hartree-Fock theory from semidefinite programming with applications to strongly correlated quantum systems.

Science.gov (United States)

Veeraraghavan, Srikant; Mazziotti, David A

2014-03-28

We present a density matrix approach for computing global solutions of restricted open-shell Hartree-Fock theory, based on semidefinite programming (SDP), that gives upper and lower bounds on the Hartree-Fock energy of quantum systems. While wave function approaches to Hartree-Fock theory yield an upper bound to the Hartree-Fock energy, we derive a semidefinite relaxation of Hartree-Fock theory that yields a rigorous lower bound on the Hartree-Fock energy. We also develop an upper-bound algorithm in which Hartree-Fock theory is cast as a SDP with a nonconvex constraint on the rank of the matrix variable. Equality of the upper- and lower-bound energies guarantees that the computed solution is the globally optimal solution of Hartree-Fock theory. The work extends a previously presented method for closed-shell systems [S. Veeraraghavan and D. A. Mazziotti, Phys. Rev. A 89, 010502-R (2014)]. For strongly correlated systems the SDP approach provides an alternative to the locally optimized Hartree-Fock energies and densities with a certificate of global optimality. Applications are made to the potential energy curves of C2, CN, Cr2, and NO2.

Local correlation detection with linearity enhancement in streaming data

KAUST Repository

Xie, Qing

2013-01-01

This paper addresses the challenges in detecting the potential correlation between numerical data streams, which facilitates the research of data stream mining and pattern discovery. We focus on local correlation with delay, which may occur in burst at different time in different streams, and last for a limited period. The uncertainty on the correlation occurrence and the time delay make it diff cult to monitor the correlation online. Furthermore, the conventional correlation measure lacks the ability of ref ecting visual linearity, which is more desirable in reality. This paper proposes effective methods to continuously detect the correlation between data streams. Our approach is based on the Discrete Fourier Transform to make rapid cross-correlation calculation with time delay allowed. In addition, we introduce a shape-based similarity measure into the framework, which ref nes the results by representative trend patterns to enhance the signif cance of linearity. The similarity of proposed linear representations can quickly estimate the correlation, and the window sliding strategy in segment level improves the eff ciency for online detection. The empirical study demonstrates the accuracy of our detection approach, as well as more than 30% improvement of eff ciency. Copyright 2013 ACM.

Globally conformal invariant gauge field theory with rational correlation functions

CERN Document Server

Nikolov, N M; Todorov, I T; CERN. Geneva; Todorov, Ivan T.

2003-01-01

Operator product expansions (OPE) for the product of a scalar field with its conjugate are presented as infinite sums of bilocal fields $V_{\\kappa} (x_1, x_2)$ of dimension $(\\kappa, \\kappa)$. For a {\\it globally conformal invariant} (GCI) theory we write down the OPE of $V_{\\kappa}$ into a series of {\\it twist} (dimension minus rank) $2\\kappa$ symmetric traceless tensor fields with coefficients computed from the (rational) 4-point function of the scalar field. We argue that the theory of a GCI hermitian scalar field ${\\cal L} (x)$ of dimension 4 in $D = 4$ Minkowski space such that the 3-point functions of a pair of ${\\cal L}$'s and a scalar field of dimension 2 or 4 vanish can be interpreted as the theory of local observables of a conformally invariant fixed point in a gauge theory with Lagrangian density ${\\cal L} (x)$.

Localization of Bogoliubov quasiparticles in interacting Bose gases with correlated disorder

International Nuclear Information System (INIS)

Lugan, P.; Sanchez-Palencia, L.

2011-01-01

We study the Anderson localization of Bogoliubov quasiparticles (elementary many-body excitations) in a weakly interacting Bose gas of chemical potential μ subjected to a disordered potential V. We introduce a general mapping (valid for weak inhomogeneous potentials in any dimension) of the Bogoliubov-de Gennes equations onto a single-particle Schroedinger-like equation with an effective potential. For disordered potentials, the Schroedinger-like equation accounts for the scattering and localization properties of the Bogoliubov quasiparticles. We derive analytically the localization lengths for correlated disordered potentials in the one-dimensional geometry. Our approach relies on a perturbative expansion in V/μ, which we develop up to third order, and we discuss the impact of the various perturbation orders. Our predictions are shown to be in very good agreement with direct numerical calculations. We identify different localization regimes: For low energy, the effective disordered potential exhibits a strong screening by the quasicondensate density background, and localization is suppressed. For high-energy excitations, the effective disordered potential reduces to the bare disordered potential, and the localization properties of quasiparticles are the same as for free particles. The maximum of localization is found at intermediate energy when the quasicondensate healing length is of the order of the disorder correlation length. Possible extensions of our work to higher dimensions are also discussed.

Improved distorted wave theory with the localized virial conditions

Science.gov (United States)

Hahn, Y. K.; Zerrad, E.

2009-12-01

The distorted wave theory is operationally improved to treat the full collision amplitude, such that the corrections to the distorted wave Born amplitude can be systematically calculated. The localized virial conditions provide the tools necessary to test the quality of successive approximations at each stage and to optimize the solution. The details of the theoretical procedure are explained in concrete terms using a collisional ionization model and variational trial functions. For the first time, adjustable parameters associated with an approximate scattering solution can be fully determined by the theory. A small number of linear parameters are introduced to examine the convergence property and the effectiveness of the new approach.

Rate Theory for Correlated Processes: Double Jumps in Adatom Diffusion

DEFF Research Database (Denmark)

Jacobsen, J.; Jacobsen, Karsten Wedel; Sethna, J.

1997-01-01

We study the rate of activated motion over multiple barriers, in particular the correlated double jump of an adatom diffusing on a missing-row reconstructed platinum (110) surface. We develop a transition path theory, showing that the activation energy is given by the minimum-energy trajectory...... which succeeds in the double jump. We explicitly calculate this trajectory within an effective-medium molecular dynamics simulation. A cusp in the acceptance region leads to a root T prefactor for the activated rate of double jumps. Theory and numerical results agree....

No-signaling, perfect bipartite dichotomic correlations and local randomness

International Nuclear Information System (INIS)

Seevinck, M. P.

2011-01-01

The no-signaling constraint on bi-partite correlations is reviewed. It is shown that in order to obtain non-trivial Bell-type inequalities that discern no-signaling correlations from more general ones, one must go beyond considering expectation values of products of observables only. A new set of nontrivial no-signaling inequalities is derived which have a remarkably close resemblance to the CHSH inequality, yet are fundamentally different. A set of inequalities by Roy and Singh and Avis et al., which is claimed to be useful for discerning no-signaling correlations, is shown to be trivially satisfied by any correlation whatsoever. Finally, using the set of newly derived no-signaling inequalities a result with potential cryptographic consequences is proven: if different parties use identical devices, then, once they have perfect correlations at spacelike separation between dichotomic observables, they know that because of no-signaling the local marginals cannot but be completely random.

Effect of the nonlocal exchange on the performance of the orbital-dependent correlation functionals from second-order perturbation theory.

Science.gov (United States)

Schweigert, Igor V; Bartlett, Rodney J

2008-09-28

Adding a fraction of the nonlocal exchange operator to the local orbital-dependent exchange potential improves the many-body perturbation expansion based on the Kohn-Sham determinant. The effect of such a hybrid scheme on the performance of the orbital-dependent correlation functional from the second-order perturbation theory (PT2H) is investigated numerically. A small fraction of the nonlocal exchange is often sufficient to ensure the existence of the self-consistent solution for the PT2H potential. In the He and Be atoms, including 37% of the nonlocal exchange leads to the correlation energies and electronic densities that are very close to the exact ones. In molecules, varying the fraction of the nonlocal exchange may result in the PT2H energy closely reproducing the CCSD(T) value; however such a fraction depends on the system and does not always result in an accurate electronic density. We also numerically verify that the "semicanonical" perturbation series includes most of the beneficial effects of the nonlocal exchange without sacrificing the locality of the exchange potential.

Approximate self-consistent potentials for density-functional-theory exchange-correlation functionals

International Nuclear Information System (INIS)

Cafiero, Mauricio; Gonzalez, Carlos

2005-01-01

We show that potentials for exchange-correlation functionals within the Kohn-Sham density-functional-theory framework may be written as potentials for simpler functionals multiplied by a factor close to unity, and in a self-consistent field calculation, these effective potentials find the correct self-consistent solutions. This simple theory is demonstrated with self-consistent exchange-only calculations of the atomization energies of some small molecules using the Perdew-Kurth-Zupan-Blaha (PKZB) meta-generalized-gradient-approximation (meta-GGA) exchange functional. The atomization energies obtained with our method agree with or surpass previous meta-GGA calculations performed in a non-self-consistent manner. The results of this work suggest the utility of this simple theory to approximate exchange-correlation potentials corresponding to energy functionals too complicated to generate closed forms for their potentials. We hope that this method will encourage the development of complex functionals which have correct boundary conditions and are free of self-interaction errors without the worry that the functionals are too complex to differentiate to obtain potentials

Stress-stress correlator in ϕ 4 theory: poles or a cut?

Science.gov (United States)

Moore, Guy D.

2018-05-01

We explore the analytical properties of the traceless stress tensor 2-point function at zero momentum and small frequency (relevant for shear viscosity and hydrodynamic response) in hot, weakly coupled λ ϕ 4 theory. We show that, rather than one or a small number of poles, the correlator has a cut along the negative imaginary frequency axis. We briefly discuss this result's relevance for constructing 2'nd order hydrodynamic models of hot relativistic field theories.

Locally semisimple algebras. Combinatorial theory and the K0-functor

International Nuclear Information System (INIS)

Vershik, A.M.; Kerov, S.V.

1987-01-01

Survey is devoted to theory of locally finite algebras and approximately finite-dimensional absolute value of AF- C*-algebras which has been developed intensively in recent years. It can serve as an introduction to the subject. Both known and new results are contained in it

Testing the non-locality of quantum theory in two-kaon systems

Energy Technology Data Exchange (ETDEWEB)

Eberhard, P.H. (California Univ., Berkeley (United States). Lawrence Berkeley Lab.)

1993-06-07

An idea for testing the non-local character of quantum theory in systems made of two neutral kaons is suggested. Such tests require detecting two long-lived or two short-lived neutral kaons in coincidence, when copper slabs are either interposed on or removed from their paths. They may be performed at an asymmetric [Phi][sup 0]-factory. They could answer some questions raised by the EPR paradox and Bell's inequalities. If such tests are performed and if predictions of quantum mechanics and standard theory of kaon regeneration are verified experimentally, all descriptions of the relevant phenomena in terms of local interactions will be ruled out in principle with the exception of very peculiar ones, which imply the existence of hidden variables, of different kinds of kaons corresponding to different values of the hidden variables, and, for some of these kaons, of regeneration probabilities enhanced by a factor of the order of 400 or more over the average. Of course, the experiment may also reveal a break down of quantum theory. (orig.)

Local normalization: Uncovering correlations in non-stationary financial time series

Science.gov (United States)

Schäfer, Rudi; Guhr, Thomas

2010-09-01

The measurement of correlations between financial time series is of vital importance for risk management. In this paper we address an estimation error that stems from the non-stationarity of the time series. We put forward a method to rid the time series of local trends and variable volatility, while preserving cross-correlations. We test this method in a Monte Carlo simulation, and apply it to empirical data for the S&P 500 stocks.

Short-range correlations in an extended time-dependent mean-field theory

International Nuclear Information System (INIS)

Madler, P.

1982-01-01

A generalization is performed of the time-dependent mean-field theory by an explicit inclusion of strong short-range correlations on a level of microscopic reversibility relating them to realistic nucleon-nucleon forces. Invoking a least action principle for correlated trial wave functions, equations of motion for the correlation functions and the single-particle model wave function are derived in lowest order of the FAHT cluster expansion. Higher order effects as well as long-range correlations are consider only to the extent to which they contribute to the mean field via a readjusted phenomenological effective two-body interaction. The corresponding correlated stationary problem is investigated and appropriate initial conditions to describe a heavy ion reaction are proposed. The singleparticle density matrix is evaluated

To the non-local theory of cold nuclear fusion.

Science.gov (United States)

Alexeev, Boris V

2014-10-01

In this paper, we revisit the cold fusion (CF) phenomenon using the generalized Bolzmann kinetics theory which can represent the non-local physics of this CF phenomenon. This approach can identify the conditions when the CF can take place as the soliton creation under the influence of the intensive sound waves. The vast mathematical modelling leads to affirmation that all parts of soliton move with the same velocity and with the small internal change of the pressure. The zone of the high density is shaped on the soliton's front. It means that the regime of the 'acoustic CF' could be realized from the position of the non-local hydrodynamics.

Localization of elastic layers by correlated disorder

International Nuclear Information System (INIS)

Balents, L.

1993-01-01

The equilibrium behavior of a system of elastic layers under tension in the presence of correlated disorder is studied using functional renormalization group techniques. The model exhibits many of the features of the Bose-glass phase of type-II superconductors induced by columnar defects, but may be more directly applicable to charge density waves, incommensurate striped magnetic phases, stacked membranes under tension, vicinal crystal surfaces, or superconducting ''vortex-chains''. Below five dimensions, an epsilon expansion for the stable zero-temperature fixed point yields the properties of the glassy phase. Transverse to the direction of correlation, the randomness induces logarithmic growth of displacements. The absence of a response to a weak applied transverse field (transverse Meissner effect) is demonstrated analytically. In this simple model, the localized phase is stable to point disorder, in contrast to the behavior in the presence of dislocations, in which the converse is believed to be true. (orig.)

Local Genetic Correlation Gives Insights into the Shared Genetic Architecture of Complex Traits.

Science.gov (United States)

Shi, Huwenbo; Mancuso, Nicholas; Spendlove, Sarah; Pasaniuc, Bogdan

2017-11-02

Although genetic correlations between complex traits provide valuable insights into epidemiological and etiological studies, a precise quantification of which genomic regions disproportionately contribute to the genome-wide correlation is currently lacking. Here, we introduce ρ-HESS, a technique to quantify the correlation between pairs of traits due to genetic variation at a small region in the genome. Our approach requires GWAS summary data only and makes no distributional assumption on the causal variant effect sizes while accounting for linkage disequilibrium (LD) and overlapping GWAS samples. We analyzed large-scale GWAS summary data across 36 quantitative traits, and identified 25 genomic regions that contribute significantly to the genetic correlation among these traits. Notably, we find 6 genomic regions that contribute to the genetic correlation of 10 pairs of traits that show negligible genome-wide correlation, further showcasing the power of local genetic correlation analyses. Finally, we report the distribution of local genetic correlations across the genome for 55 pairs of traits that show putative causal relationships. Copyright © 2017 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Feature Genes Selection Using Supervised Locally Linear Embedding and Correlation Coefficient for Microarray Classification.

Science.gov (United States)

Xu, Jiucheng; Mu, Huiyu; Wang, Yun; Huang, Fangzhou

2018-01-01

The selection of feature genes with high recognition ability from the gene expression profiles has gained great significance in biology. However, most of the existing methods have a high time complexity and poor classification performance. Motivated by this, an effective feature selection method, called supervised locally linear embedding and Spearman's rank correlation coefficient (SLLE-SC 2 ), is proposed which is based on the concept of locally linear embedding and correlation coefficient algorithms. Supervised locally linear embedding takes into account class label information and improves the classification performance. Furthermore, Spearman's rank correlation coefficient is used to remove the coexpression genes. The experiment results obtained on four public tumor microarray datasets illustrate that our method is valid and feasible.

Energy momentum tensor and operator product expansion in local causal perturbation theory

International Nuclear Information System (INIS)

Prange, D.

2000-09-01

We derive new examples for algebraic relations of interacting fields in local perturbative quantum field theory. The fundamental building blocks in this approach are time ordered products of free (composed) fields. We give explicit formulas for the construction of Poincare covariant ones, which were already known to exist through cohomological arguments. For a large class of theories the canonical energy momentum tensor is shown to be conserved. Classical theories without dimensionful couplings admit an improved tensor that is additionally traceless. On the example of φ 4 -theory we discuss the improved tensor in the quantum theory. Its trace receives an anomalous contribution due to its conservation. Moreover, we define an interacting bilocal normal product for scalar theories. This leads to an operator product expansion of two time ordered fields. (orig.) [de

Quasigroup of local-symmetry transformations in constrained theories

International Nuclear Information System (INIS)

Chitaya, N.P.; Gogilidze, S.A.; Surovtsev, Yu.S.

1996-01-01

In the framework of the generalized Hamiltonian formalism by Dirac, the local symmetries of dynamical systems with first- and second-class constraints are investigated in the general case without restrictions on the algebra of constraints. The method of constructing the generator of local-symmetry transformations is obtained from the requirement for them to map the solutions of the Hamiltonian equations of motion into the solutions of the same equations. It is proved that second-class constraints do not contribute to the transformation law of the local symmetry entirely stipulated by all the first-class constraints (only by them) of an equivalent set passing to which from the initial constraint set is always possible and is presented. A mechanism of occurrence of higher derivatives of coordinates and group parameters in the symmetry transformation law in the Noether second theorem is elucidated. In the latter case it is shown that the obtained transformations of symmetry are canonical in the extended (by Ostrogradsky) phase space. It is thereby shown in the general case that the degeneracy of theories with the first- and second-class constraints is due to their invariance under local-symmetry transformations. It is also shown in the general case that the action functional and the corresponding Hamiltonian equations of motion are invariant under the same quasigroup of local-symmetry transformations. 29 refs

Bond breaking and bond formation: how electron correlation is captured in many-body perturbation theory and density-functional theory.

Science.gov (United States)

Caruso, Fabio; Rohr, Daniel R; Hellgren, Maria; Ren, Xinguo; Rinke, Patrick; Rubio, Angel; Scheffler, Matthias

2013-04-05

For the paradigmatic case of H(2) dissociation, we compare state-of-the-art many-body perturbation theory in the GW approximation and density-functional theory in the exact-exchange plus random-phase approximation (RPA) for the correlation energy. For an unbiased comparison and to prevent spurious starting point effects, both approaches are iterated to full self-consistency (i.e., sc-RPA and sc-GW). The exchange-correlation diagrams in both approaches are topologically identical, but in sc-RPA they are evaluated with noninteracting and in sc-GW with interacting Green functions. This has a profound consequence for the dissociation region, where sc-RPA is superior to sc-GW. We argue that for a given diagrammatic expansion, sc-RPA outperforms sc-GW when it comes to bond breaking. We attribute this to the difference in the correlation energy rather than the treatment of the kinetic energy.

Local Field Response Method Phenomenologically Introducing Spin Correlations

Science.gov (United States)

Tomaru, Tatsuya

2018-03-01

The local field response (LFR) method is a way of searching for the ground state in a similar manner to quantum annealing. However, the LFR method operates on a classical machine, and quantum effects are introduced through a priori information and through phenomenological means reflecting the states during the computations. The LFR method has been treated with a one-body approximation, and therefore, the effect of entanglement has not been sufficiently taken into account. In this report, spin correlations are phenomenologically introduced as one of the effects of entanglement, by which multiple tunneling at anticrossing points is taken into account. As a result, the accuracy of solutions for a 128-bit system increases by 31% compared with that without spin correlations.

Relativistic time-dependent local-density approximation theory and applications to atomic physics

International Nuclear Information System (INIS)

Parpia, F.Z.

1984-01-01

A time-dependent linear-response theory appropriate to the relativistic local-density approximation (RLDA) to quantum electrodynamics (QED) is developed. The resulting theory, the relativistic time-dependent local-density approximation (RTDLDA) is specialized to the treatment of electric excitations in closed-shell atoms. This formalism is applied to the calculation of atomic photoionization parameters in the dipole approximation. The static-field limit of the RTDLDA is applied to the calculation of dipole polarizabilities. Extensive numerical calculations of the photoionization parameters for the rare gases neon, argon, krypton, and xenon, and for mercury from the RTDLDA are presented and compared in detail with the results of other theories, in particular the relativistic random-phase approximation (RRPA), and with experimental measurements. The predictions of the RTDLDA are comparable with the RRPA calculations made to date. This is remarkable in that the RTDLDA entails appreciably less computational effort. Finally, the dipole polarizabilities predicted by the static-field RTDLDA are compared with other determinations of these quantities. In view of its simplicity, the static-field RTDLDA demonstrates itself to be one of the most powerful theories available for the calculation of dipole polarizabilities

Batalin-Vilkovisky formalism in locally covariant field theory

International Nuclear Information System (INIS)

Rejzner, Katarzyna Anna

2011-12-01

The present work contains a complete formulation of the Batalin-Vilkovisky (BV) formalism in the framework of locally covariant field theory. In the first part of the thesis the classical theory is investigated with a particular focus on the infinite dimensional character of the underlying structures. It is shown that the use of infinite dimensional differential geometry allows for a conceptually clear and elegant formulation. The construction of the BV complex is performed in a fully covariant way and we also generalize the BV framework to a more abstract level, using functors and natural transformations. In this setting we construct the BV complex for classical gravity. This allows us to give a homological interpretation to the notion of diffeomorphism invariant physical quantities in general relativity. The second part of the thesis concerns the quantum theory. We provide a framework for the BV quantization that doesn't rely on the path integral formalism, but is completely formulated within perturbative algebraic quantum field theory. To make such a formulation possible we first prove that the renormalized time-ordered product can be understood as a binary operation on a suitable domain. Using this result we prove the associativity of this product and provide a consistent framework for the renormalized BV structures. In particular the renormalized quantum master equation and the renormalized quantum BV operator are defined. To give a precise meaning to theses objects we make a use of the master Ward identity, which is an important structure in causal perturbation theory. (orig.)

Batalin-Vilkovisky formalism in locally covariant field theory

Energy Technology Data Exchange (ETDEWEB)

Rejzner, Katarzyna Anna

2011-12-15

The present work contains a complete formulation of the Batalin-Vilkovisky (BV) formalism in the framework of locally covariant field theory. In the first part of the thesis the classical theory is investigated with a particular focus on the infinite dimensional character of the underlying structures. It is shown that the use of infinite dimensional differential geometry allows for a conceptually clear and elegant formulation. The construction of the BV complex is performed in a fully covariant way and we also generalize the BV framework to a more abstract level, using functors and natural transformations. In this setting we construct the BV complex for classical gravity. This allows us to give a homological interpretation to the notion of diffeomorphism invariant physical quantities in general relativity. The second part of the thesis concerns the quantum theory. We provide a framework for the BV quantization that doesn't rely on the path integral formalism, but is completely formulated within perturbative algebraic quantum field theory. To make such a formulation possible we first prove that the renormalized time-ordered product can be understood as a binary operation on a suitable domain. Using this result we prove the associativity of this product and provide a consistent framework for the renormalized BV structures. In particular the renormalized quantum master equation and the renormalized quantum BV operator are defined. To give a precise meaning to theses objects we make a use of the master Ward identity, which is an important structure in causal perturbation theory. (orig.)

Unified description of perturbation theory and band center anomaly in one-dimensional Anderson localization

International Nuclear Information System (INIS)

Kang, Kai; Qin, Shaojing; Wang, Chuilin

2011-01-01

We calculated numerically the localization length of one-dimensional Anderson model with diagonal disorder. For weak disorder, we showed that the localization length changes continuously as the energy changes from the band center to the boundary of the anomalous region near the band edge. We found that all the localization lengths for different disorder strengths and different energies collapse onto a single curve, which can be fitted by a simple equation. Thus the description of the perturbation theory and the band center anomaly were unified into this equation. -- Highlights: → We study the band center anomaly of one-dimensional Anderson localization. → We study numerically the Lyapunov exponent through a parametrization method of the transfer matrix. → We give a unified equation to describe the band center anomaly and perturbation theory.

Wigner particle theory and local quantum physics

International Nuclear Information System (INIS)

Fassarella, Lucio; Schroer, Bert

2002-01-01

Wigner's irreducible positive energy representations of the Poincare group are often used to give additional justifications for the Lagrangian quantization formalism of standard QFT. Here we study another more recent aspect. We explain in this paper modular concepts by which we are able to construct the local operator algebras for all standard positive energy representations directly without going through field coordinations. In this way the artificial emphasis on Lagrangian field coordinates is avoided from the very beginning. These new concepts allow to treat also those cases of 'exceptional' Wigner representations associated with anyons and the famous Wigner spin tower which have remained inaccessible to Lagrangian quantization. Together with the d=1+1 factorizing models (whose modular construction has been studied previously), they form an interesting family of theories with a rich vacuum-polarization structure (but no on shell real particle creation) to which the modular methods can be applied for their explicit construction. We explain and illustrate the algebraic strategy of this construction. We also comment on possibilities of formulating the Wigner theory in a setting of a noncommutativity. (author)

Local vibrational modes of the water dimer - Comparison of theory and experiment

Science.gov (United States)

Kalescky, R.; Zou, W.; Kraka, E.; Cremer, D.

2012-12-01

Local and normal vibrational modes of the water dimer are calculated at the CCSD(T)/CBS level of theory. The local H-bond stretching frequency is 528 cm-1 compared to a normal mode stretching frequency of just 143 cm-1. The adiabatic connection scheme between local and normal vibrational modes reveals that the lowering is due to mass coupling, a change in the anharmonicity, and coupling with the local HOH bending modes. The local mode stretching force constant is related to the strength of the H-bond whereas the normal mode stretching force constant and frequency lead to an erroneous underestimation of the H-bond strength.

Characterization of identification errors and uses in localization of poor modal correlation

Science.gov (United States)

Martin, Guillaume; Balmes, Etienne; Chancelier, Thierry

2017-05-01

While modal identification is a mature subject, very few studies address the characterization of errors associated with components of a mode shape. This is particularly important in test/analysis correlation procedures, where the Modal Assurance Criterion is used to pair modes and to localize at which sensors discrepancies occur. Poor correlation is usually attributed to modeling errors, but clearly identification errors also occur. In particular with 3D Scanning Laser Doppler Vibrometer measurement, many transfer functions are measured. As a result individual validation of each measurement cannot be performed manually in a reasonable time frame and a notable fraction of measurements is expected to be fairly noisy leading to poor identification of the associated mode shape components. The paper first addresses measurements and introduces multiple criteria. The error measures the difference between test and synthesized transfer functions around each resonance and can be used to localize poorly identified modal components. For intermediate error values, diagnostic of the origin of the error is needed. The level evaluates the transfer function amplitude in the vicinity of a given mode and can be used to eliminate sensors with low responses. A Noise Over Signal indicator, product of error and level, is then shown to be relevant to detect poorly excited modes and errors due to modal property shifts between test batches. Finally, a contribution is introduced to evaluate the visibility of a mode in each transfer. Using tests on a drum brake component, these indicators are shown to provide relevant insight into the quality of measurements. In a second part, test/analysis correlation is addressed with a focus on the localization of sources of poor mode shape correlation. The MACCo algorithm, which sorts sensors by the impact of their removal on a MAC computation, is shown to be particularly relevant. Combined with the error it avoids keeping erroneous modal components

Local density approximation for exchange in excited-state density functional theory

OpenAIRE

Harbola, Manoj K.; Samal, Prasanjit

2004-01-01

Local density approximation for the exchange energy is made for treatment of excited-states in density-functional theory. It is shown that taking care of the state-dependence of the LDA exchange energy functional leads to accurate excitation energies.

Localization and diagonalization. A review of functional integral techniques for low-dimensional gauge theories and topological field theories

International Nuclear Information System (INIS)

Blau, M.; Thompson, G.

1995-01-01

We review localization techniques for functional integrals which have recently been used to perform calculations in and gain insight into the structure of certain topological field theories and low-dimensional gauge theories. These are the functional integral counterparts of the Mathai-Quillen formalism, the Duistermaat-Heckman theorem, and the Weyl integral formula respectively. In each case, we first introduce the necessary mathematical background (Euler classes of vector bundles, equivariant cohomology, topology of Lie groups), and describe the finite dimensional integration formulae. We then discuss some applications to path integrals and give an overview of the relevant literature. The applications we deal with include supersymmetric quantum mechanics, cohomological field theories, phase space path integrals, and two-dimensional Yang-Mills theory. (author). 83 refs

The physics of flocking: Correlation as a compass from experiments to theory

Science.gov (United States)

Cavagna, Andrea; Giardina, Irene; Grigera, Tomás S.

2018-01-01

Collective behavior in biological systems is a complex topic, to say the least. It runs wildly across scales in both space and time, involving taxonomically vastly different organisms, from bacteria and cell clusters, to insect swarms and up to vertebrate groups. It entails concepts as diverse as coordination, emergence, interaction, information, cooperation, decision-making, and synchronization. Amid this jumble, however, we cannot help noting many similarities between collective behavior in biological systems and collective behavior in statistical physics, even though none of these organisms remotely looks like an Ising spin. Such similarities, though somewhat qualitative, are startling, and regard mostly the emergence of global dynamical patterns qualitatively different from individual behavior, and the development of system-level order from local interactions. It is therefore tempting to describe collective behavior in biology within the conceptual framework of statistical physics, in the hope to extend to this new fascinating field at least part of the great predictive power of theoretical physics. In this review we propose that the conceptual cornerstone of this ambitious program be that of correlation. To illustrate this idea we address the case of collective behavior in bird flocks. Two key threads emerge, as two sides of one single story: the presence of scale-free correlations and the dynamical mechanism of information transfer. We discuss first static correlations in starling flocks, in particular the experimental finding of their scale-free nature, the formulation of models that account for this fact using maximum entropy, and the relation of scale-free correlations to information transfer. This is followed by a dynamic treatment of information propagation (propagation of turns across a flock), starting with a discussion of experimental results and following with possible theoretical explanations of those, which require the addition of behavioral

Plasma balls in large-N gauge theories and localized black holes

International Nuclear Information System (INIS)

Aharony, Ofer; Minwalla, Shiraz; Wiseman, Toby

2006-01-01

We argue for the existence of plasma balls-metastable, nearly homogeneous lumps of gluon plasma at just above the deconfinement energy density-in a class of large-N confining gauge theories that undergo first-order deconfinement transitions. Plasma balls decay over a time scale of order N 2 by thermally radiating hadrons at the deconfinement temperature. In gauge theories that have a dual description that is well approximated by a theory of gravity in a warped geometry, we propose that plasma balls map to a family of classically stable finite-energy black holes localized in the IR. We present a conjecture for the qualitative nature of large-mass black holes in such backgrounds and numerically construct these black holes in a particular class of warped geometries. These black holes have novel properties; in particular, their temperature approaches a nonzero constant value at large mass. Black holes dual to plasma balls shrink as they decay by Hawking radiation; towards the end of this process, they resemble ten-dimensional Schwarzschild black holes, which we propose are dual to small plasma balls. Our work may find practical applications in the study of the physics of localized black holes from a dual viewpoint

S-pairing in neutron matter: I. Correlated basis function theory

International Nuclear Information System (INIS)

Fabrocini, Adelchi; Fantoni, Stefano; Illarionov, Alexey Yu.; Schmidt, Kevin E.

2008-01-01

S-wave pairing in neutron matter is studied within an extension of correlated basis function (CBF) theory to include the strong, short range spatial correlations due to realistic nuclear forces and the pairing correlations of the Bardeen, Cooper and Schrieffer (BCS) approach. The correlation operator contains central as well as tensor components. The correlated BCS scheme of [S. Fantoni, Nucl. Phys. A 363 (1981) 381], developed for simple scalar correlations, is generalized to this more realistic case. The energy of the correlated pair condensed phase of neutron matter is evaluated at the two-body order of the cluster expansion, but considering the one-body density and the corresponding energy vertex corrections at the first order of the Power Series expansion. Based on these approximations, we have derived a system of Euler equations for the correlation factors and for the BCS amplitudes, resulting in correlated nonlinear gap equations, formally close to the standard BCS ones. These equations have been solved for the momentum independent part of several realistic potentials (Reid, Argonne v 14 and Argonne v 8 ' ) to stress the role of the tensor correlations and of the many-body effects. Simple Jastrow correlations and/or the lack of the density corrections enhance the gap with respect to uncorrelated BCS, whereas it is reduced according to the strength of the tensor interaction and following the inclusion of many-body contributions

Shift versus no-shift in local regularization of Chern-Simons theory

International Nuclear Information System (INIS)

Giavarini, G.; Parma Univ.; Martin, C.P.; Ruiz Ruiz, F.

1994-01-01

We consider a family of local BRS-invariant higher covariant derivative regularizations of SU(N) Chern-Simons theory that do not shift the value of the Chern-Simons parameter k to k + sign(k) c v at one loop. (orig.)

Reality, measurement and locality in Quantum Field Theory

International Nuclear Information System (INIS)

Tommasini, Daniele

2002-01-01

It is currently believed that the local causality of Quantum Field Theory (QFT) is destroyed by the measurement process. This belief is also based on the Einstein-Podolsky-Rosen (EPR) paradox and on the so-called Bell's theorem, that are thought to prove the existence of a mysterious, instantaneous action between distant measurements. However, I have shown recently that the EPR argument is removed, in an interpretation-independent way, by taking into account the fact that the Standard Model of Particle Physics prevents the production of entangled states with a definite number of particles. This result is used here to argue in favor of a statistical interpretation of QFT and to show that it allows for a full reconciliation with locality and causality. Within such an interpretation, as Ballentine and Jarret pointed out long ago, Bell's theorem does not demonstrate any nonlocality. (author)

Local existence of N=1 supersymmetric gauge theory in four Dimensions

Energy Technology Data Exchange (ETDEWEB)

Akbar, Fiki T. [Theoretical Physics Laboratory, Theoretical High Energy Physics and Instrumentation Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung Jl. Ganesha no. 10 Bandung, 40132 (Indonesia); Gunara, Bobby E.; Zen, Freddy P.; Triyanta [Theoretical Physics Laboratory, Theoretical High Energy Physics and Instrumentation Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung Jl. Ganesha no. 10 Bandung, 40132 (Indonesia); Indonesian Center of Theoretical and Mathematical Physics (ICTMP) (Indonesia)

2015-04-16

In this paper, we shall prove the local existence of N=1 supersymmetry gauge theory in 4 dimension. We start from the Lagrangian for coupling chiral and vector multiplets with constant gauge kinetic function and only considering a bosonic part by setting all fermionic field to be zero at level equation of motion. We consider a U(n) model as isometry for scalar field internal geometry. And we use a nonlinear semigroup method to prove the local existence.

Local extinction and the evolution of dispersal rates: Causes and correlations

OpenAIRE

Poethke, Hans-Joachim; Hovestadt, Thomas; Mitesser, Oliver

2010-01-01

We present the results of individual-based simulation experiments on the evolution of dispersal rates of organisms living in metapopulations. We find conflicting results regarding the relationship between local extinction rate and evolutionarily stable (ES) dispersal rate depending on which principal mechanism causes extinction: if extinction is caused by environmental catastrophes eradicating local populations, we observe a positive correlation between extinction and ES dispersal rate; if ex...

Self-Interaction Error in Density Functional Theory: An Appraisal.

Science.gov (United States)

Bao, Junwei Lucas; Gagliardi, Laura; Truhlar, Donald G

2018-05-03

Self-interaction error (SIE) is considered to be one of the major sources of error in most approximate exchange-correlation functionals for Kohn-Sham density-functional theory (KS-DFT), and it is large with all local exchange-correlation functionals and with some hybrid functionals. In this work, we consider systems conventionally considered to be dominated by SIE. For these systems, we demonstrate that by using multiconfiguration pair-density functional theory (MC-PDFT), the error of a translated local density-functional approximation is significantly reduced (by a factor of 3) when using an MCSCF density and on-top density, as compared to using KS-DFT with the parent functional; the error in MC-PDFT with local on-top functionals is even lower than the error in some popular KS-DFT hybrid functionals. Density-functional theory, either in MC-PDFT form with local on-top functionals or in KS-DFT form with some functionals having 50% or more nonlocal exchange, has smaller errors for SIE-prone systems than does CASSCF, which has no SIE.

Star-product functions in higher-spin theory and locality

Energy Technology Data Exchange (ETDEWEB)

Vasiliev, M.A. [I.E. Tamm Department of Theoretical Physics, Lebedev Physical Institute,Leninsky prospect 53, 119991, Moscow (Russian Federation)

2015-06-04

Properties of the functional classes of star-product elements associated with higher-spin gauge fields and gauge parameters are elaborated. Cohomological interpretation of the nonlinear higher-spin equations is given. An algebra ℋ, where solutions of the nonlinear higher-spin equations are valued, is found. A conjecture on the classes of star-product functions underlying (non)local maps and gauge transformations in the nonlinear higher-spin theory is proposed.

Evaluation of Forming Limit by the 3 Dimensional Local Bifurcation Theory

International Nuclear Information System (INIS)

Nishimura, Ryuichi; Nakazawa, Yoshiaki; Ito, Koichi; Uemura, Gen; Mori, Naomichi

2007-01-01

A theoretical prediction and evaluation method for the sheet metal formability is developed on the basis of the three-dimensional local bifurcation theory previously proposed by authors. The forming limit diagram represented on the plane defined by the ratio of stress component to work-hardening rate is perfectly independent of plastic strain history. The upper and the lower limit of the sheet formability are indicated by the 3D critical line and the Stoeren-Rice's critical line on this plane, respectively. In order to verify the above mentioned behavior of the proposed forming limit diagram, the experimental research is also conducted. From the standpoint of the mechanical instability theory, a new concept called instability factor is introduced. It represents a degree of acceleration by current stress for developing the local bifurcation mode toward a fracture. The instability factor provides a method to evaluate a forming allowance which is useful to appropriate identification for a forming limit and to optimize the forming condition. The proposed criterion provides not only the moment to initiate the necking but also the local bifurcation mode vector and the direction of necking line

Discrete gravity as a local theory of the Poincare group in the first-order formalism

Energy Technology Data Exchange (ETDEWEB)

Gionti, Gabriele [Vatican Observatory Research Group, Steward Observatory, 933 North Cherry Avenue, University of Arizona, Tucson, AZ 85721 (United States); Specola Vaticana, V-00120 Citta Del Vaticano (Vatican City State, Holy See,)

2005-10-21

A discrete theory of gravity, locally invariant under the Poincare group, is considered as in a companion paper. We define a first-order theory, in the sense of Palatini, on the metric-dual Voronoi complex of a simplicial complex. We follow the same spirit as the continuum theory of general relativity in the Cartan formalism. The field equations are carefully derived taking in account the constraints of the theory. They look very similar to first-order Einstein continuum equations in the Cartan formalism. It is shown that in the limit of small deficit angles these equations have Regge calculus, locally, as the only solution. A quantum measure is easily defined which does not suffer the ambiguities of Regge calculus, and a coupling with fermionic matter is easily introduced.

Discrete gravity as a local theory of the Poincare group in the first-order formalism

International Nuclear Information System (INIS)

Gionti, Gabriele

2005-01-01

A discrete theory of gravity, locally invariant under the Poincare group, is considered as in a companion paper. We define a first-order theory, in the sense of Palatini, on the metric-dual Voronoi complex of a simplicial complex. We follow the same spirit as the continuum theory of general relativity in the Cartan formalism. The field equations are carefully derived taking in account the constraints of the theory. They look very similar to first-order Einstein continuum equations in the Cartan formalism. It is shown that in the limit of small deficit angles these equations have Regge calculus, locally, as the only solution. A quantum measure is easily defined which does not suffer the ambiguities of Regge calculus, and a coupling with fermionic matter is easily introduced

Light Condensation and Localization in Disordered Photonic Media: Theory and Large Scale ab initio Simulations

KAUST Repository

Toth, Laszlo Daniel

2013-05-07

Disordered photonics is the study of light in random media. In a disordered photonic medium, multiple scattering of light and coherence, together with the fundamental principle of reciprocity, produce a wide range of interesting phenomena, such as enhanced backscattering and Anderson localization of light. They are also responsible for the existence of modes in these random systems. It is known that analogous processes to Bose-Einstein condensation can occur in classical wave systems, too. Classical condensation has been studied in several contexts in photonics: pulse formation in lasers, mode-locking theory and coherent emission of disordered lasers. All these systems have the common theme of possessing a large ensemble of waves or modes, together with nonlinearity, dispersion or gain. In this work, we study light condensation and its connection with light localization in a disordered, passive dielectric medium. We develop a theory for the modes inside the disordered resonator, which combines the Feshbach projection technique with spin-glass theory and statistical physics. In particular, starting from the Maxwell’s equations, we map the system to a spherical p-spin model with p = 2. The spins are replaced by modes and the temperature is related to the fluctuations in the environment. We study the equilibrium thermodynamics of the system in a general framework and show that two distinct phases exist: a paramagnetic phase, where all the modes are randomly oscillating and a condensed phase, where the energy condensates on a single mode. The thermodynamic quantities can be explicitly interpreted and can also be computed from the disorder-averaged time domain correlation function. We launch an ab initio simulation campaign using our own code and the Shaheen supercomputer to test the theoretical predictions. We construct photonic samples of varying disorder and find computationally relevant ways to obtain the thermodynamic quantities. We observe the phase transition

Local gauge invariant Lagrangeans in classical field theories

International Nuclear Information System (INIS)

Grigore, D.R.

1982-07-01

We investigate the most general local gauge invariant Lagrangean in the framework of classical field theory. We rederive esentially Utiyama's result with a slight generalization. Our proof makes clear the importance of the so called current conditions, i.e. the requirement that the Noether currents are different from zero. This condition is of importance both in the general motivation for the introduction of the Yang-Mills fields and for the actual proof. Some comments are made about the basic mathematical structure of the problem - the gauge group. (author)

Locally extracting scalar, vector and tensor modes in cosmological perturbation theory

International Nuclear Information System (INIS)

Clarkson, Chris; Osano, Bob

2011-01-01

Cosmological perturbation theory relies on the decomposition of perturbations into so-called scalar, vector and tensor modes. This decomposition is non-local and depends on unknowable boundary conditions. The non-locality is particularly important at second and higher order because perturbative modes are sourced by products of lower order modes, which must be integrated over all space in order to isolate each mode. However, given a trace-free rank-2 tensor, a locally defined scalar mode may be trivially derived by taking two divergences, which knocks out the vector and tensor degrees of freedom. A similar local differential operation will return a pure vector mode. This means that scalar and vector degrees of freedom have local descriptions. The corresponding local extraction of the tensor mode is unknown however. We give it here. The operators we define are useful for defining gauge-invariant quantities at second order. We perform much of our analysis using an index-free 'vector-calculus' approach which makes manipulating tensor equations considerably simpler. (papers)

Wigner particle theory and local quantum physics

Energy Technology Data Exchange (ETDEWEB)

Fassarella, Lucio; Schroer, Bert [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)]. E-mail: fassarel@cbpf.br; schroer@cbpf.br

2002-01-01

Wigner's irreducible positive energy representations of the Poincare group are often used to give additional justifications for the Lagrangian quantization formalism of standard QFT. Here we study another more recent aspect. We explain in this paper modular concepts by which we are able to construct the local operator algebras for all standard positive energy representations directly without going through field coordinations. In this way the artificial emphasis on Lagrangian field coordinates is avoided from the very beginning. These new concepts allow to treat also those cases of 'exceptional' Wigner representations associated with anyons and the famous Wigner spin tower which have remained inaccessible to Lagrangian quantization. Together with the d=1+1 factorizing models (whose modular construction has been studied previously), they form an interesting family of theories with a rich vacuum-polarization structure (but no on shell real particle creation) to which the modular methods can be applied for their explicit construction. We explain and illustrate the algebraic strategy of this construction. We also comment on possibilities of formulating the Wigner theory in a setting of a noncommutativity. (author)

Comparisons of perturbation and integral equation theories for the angular pair correlation function in molecular fluids

International Nuclear Information System (INIS)

Murad, S.; Gubbins, K.E.; Gray, C.G.

1983-01-01

We compare several recently proposed theories for the angular pair correlation function g(rω 1 ω 2 ), including first- and second-order perturbation theory (the u-expansion), a Pade approximant to this series, first-order f-expansion, the single superchain, generalized mean field, linearized hypernetted chain, and quadratic hypernetted chain approximations. Numerical results from these theories are compared with available computer simulation data for four model fluids whose intermolecular pair potential is of the form u 0 +usub(a), where u 0 is a hard-sphere of Lennard-Jones model, while usub(a) is a dipole-dipole or quadrupole-quadrupole interaction; we refer to these model fluids as HS+μμ, HS+QQ, LJ+μμ, and LJ+QQ. Properties studied include the angular pair correlation function and its spherical harmonic components, the thermodynamic properties, and the angular correlation parameters G 1 and G 2 that are related to the dielectric and Kerr constants. The second-order perturbation theory is superior to the integral equation theories for the thermodynamic harmonics of g(rω 1 ω 2 ) and for the thermodynamic properties themselves at moderate multipole strengths. For other harmonics and properties, the integral equation theories are better, with the quadratic hypernetted chain approximation being the best overall. (orig.)

Correlation between catalytic activity and bonding and coordination number of atoms and molecules on transition metal surfaces: theory and experimental evidence

International Nuclear Information System (INIS)

Falicov, L.M.; Somorjai, G.A.

1985-01-01

Correlation between catalytic activity and low-energy local electronic fluctuation in transition metals is proposed. A theory and calculations are presented which indicate that maximum electronic fluctuants take place at high-coordination metal sites. Either (i) atomically rough surfaces that expose to the reactant molecules atoms with large numbers of nonmagnetic or weakly magnetic neighbors in the first or second layer at the surface or (ii) stepped and kinked surfaces are the most active in carrying out structure-sensitive catalytic reactions. The synthesis of ammonia from N 2 and H 2 over iron and rhenium surfaces, 1 H 2 / 2 H 2 exchange over stepped platinum crystal surfaces at low pressures, and the hydrogenolysis (C - C bond breaking) of isobutane at kinked platinum crystal surfaces are presented as experimental evidence in support of the theory

Approximating the Shifted Hartree-Exchange-Correlation Potential in Direct Energy Kohn-Sham Theory.

Science.gov (United States)

Sharpe, Daniel J; Levy, Mel; Tozer, David J

2018-02-13

Levy and Zahariev [Phys. Rev. Lett. 113 113002 (2014)] have proposed a new approach for performing density functional theory calculations, termed direct energy Kohn-Sham (DEKS) theory. In this approach, the electronic energy equals the sum of orbital energies, obtained from Kohn-Sham-like orbital equations involving a shifted Hartree-exchange-correlation potential, which must be approximated. In the present study, density scaling homogeneity considerations are used to facilitate DEKS calculations on a series of atoms and molecules, leading to three nonlocal approximations to the shifted potential. The first two rely on preliminary Kohn-Sham calculations using a standard generalized gradient approximation (GGA) exchange-correlation functional and the results illustrate the benefit of describing the dominant Hartree component of the shift exactly. A uniform electron gas analysis is used to eliminate the need for these preliminary Kohn-Sham calculations, leading to a potential with an unconventional form that yields encouraging results, providing strong motivation for further research in DEKS theory.

Noncommutative Common Cause Principles in algebraic quantum field theory

International Nuclear Information System (INIS)

Hofer-Szabó, Gábor; Vecsernyés, Péter

2013-01-01

States in algebraic quantum field theory “typically” establish correlation between spacelike separated events. Reichenbach's Common Cause Principle, generalized to the quantum field theoretical setting, offers an apt tool to causally account for these superluminal correlations. In the paper we motivate first why commutativity between the common cause and the correlating events should be abandoned in the definition of the common cause. Then we show that the Noncommutative Weak Common Cause Principle holds in algebraic quantum field theory with locally finite degrees of freedom. Namely, for any pair of projections A, B supported in spacelike separated regions V A and V B , respectively, there is a local projection C not necessarily commuting with A and B such that C is supported within the union of the backward light cones of V A and V B and the set {C, C ⊥ } screens off the correlation between A and B.

Magnetizability and rotational g tensors for density fitted local second-order Møller-Plesset perturbation theory using gauge-including atomic orbitals

International Nuclear Information System (INIS)

Loibl, Stefan; Schütz, Martin

2014-01-01

In this paper, we present theory and implementation of an efficient program for calculating magnetizabilities and rotational g tensors of closed-shell molecules at the level of local second-order Møller-Plesset perturbation theory (MP2) using London orbitals. Density fitting is employed to factorize the electron repulsion integrals with ordinary Gaussians as fitting functions. The presented program for the calculation of magnetizabilities and rotational g tensors is based on a previous implementation of NMR shielding tensors reported by S. Loibl and M. Schütz [J. Chem. Phys. 137, 084107 (2012)]. Extensive test calculations show (i) that the errors introduced by density fitting are negligible, and (ii) that the errors of the local approximation are still rather small, although larger than for nuclear magnetic resonance (NMR) shielding tensors. Electron correlation effects for magnetizabilities are tiny for most of the molecules considered here. MP2 appears to overestimate the correlation contribution of magnetizabilities such that it does not constitute an improvement over Hartree-Fock (when comparing to higher-order methods like CCSD(T)). For rotational g tensors the situation is different and MP2 provides a significant improvement in accuracy over Hartree-Fock. The computational performance of the new program was tested for two extended systems, the larger comprising about 2200 basis functions. It turns out that a magnetizability (or rotational g tensor) calculation takes about 1.5 times longer than a corresponding NMR shielding tensor calculation

The correlation functions of hard-sphere chain fluids: Comparison of the Wertheim integral equation theory with the Monte Carlo simulation

International Nuclear Information System (INIS)

Chang, J.; Sandler, S.I.

1995-01-01

The correlation functions of homonuclear hard-sphere chain fluids are studied using the Wertheim integral equation theory for associating fluids and the Monte Carlo simulation method. The molecular model used in the simulations is the freely jointed hard-sphere chain with spheres that are tangentially connected. In the Wertheim theory, such a chain molecule is described by sticky hard spheres with two independent attraction sites on the surface of each sphere. The OZ-like equation for this associating fluid is analytically solved using the polymer-PY closure and by imposing a single bonding condition. By equating the mean chain length of this associating hard sphere fluid to the fixed length of the hard-sphere chains used in simulation, we find that the correlation functions for the chain fluids are accurately predicted. From the Wertheim theory we also obtain predictions for the overall correlation functions that include intramolecular correlations. In addition, the results for the average intermolecular correlation functions from the Wertheim theory and from the Chiew theory are compared with simulation results, and the differences between these theories are discussed

Superconformal field theory in three dimensions: correlation functions of conserved currents

Energy Technology Data Exchange (ETDEWEB)

Buchbinder, Evgeny I.; Kuzenko, Sergei M.; Samsonov, Igor B. [School of Physics M013, The University of Western Australia,35 Stirling Highway, Crawley W.A. 6009 (Australia)

2015-06-22

For N-extended superconformal field theories in three spacetime dimensions (3D), with 1≤N≤3, we compute the two- and three-point correlation functions of the supercurrent and the flavour current multiplets. We demonstrate that supersymmetry imposes additional restrictions on the correlators of conserved currents as compared with the non-supersymmetric case studied by Osborn and Petkou in hep-th/9307010. It is shown that the three-point function of the supercurrent is determined by a single functional form consistent with the conservation equation and all the symmetry properties. Similarly, the three-point function of the flavour current multiplets is also determined by a single functional form in the N=1 and N=3 cases. The specific feature of the N=2 case is that two independent structures are allowed for the three-point function of flavour current multiplets, but only one of them contributes to the three-point function of the conserved currents contained in these multiplets. Since the supergravity and super-Yang-Mills Ward identities are expected to relate the coefficients of the two- and three-point functions under consideration, the results obtained for 3D superconformal field theory are analogous to those in 2D conformal field theory. In addition, we present a new supertwistor construction for compactified Minkowski superspace. It is suitable for developing superconformal field theory on 3D spacetimes other than Minkowski space, such as S{sup 1}×S{sup 2} and its universal covering space ℝ×S{sup 2}.

A course on quantum field theory and local observables

International Nuclear Information System (INIS)

Schroer, Bert

1997-03-01

A monograph on Quantum Field Theory and Local Observables is presented, aiming to unify two presently largely disconnected branches of QFT, as follows: the standard (canonical, functional) approach which is mainly perturbative in the sense of an infinitesimal 'deformation' of free fields; nonperturbative constructions of low-dimensional models as the form factor-bootstrap approach (which for the time being is limited to factorable models in d=1+1 spacetime dimensions) and the non-Lagrangian constructions of conformal chiral QFT's

Restoration of the local gauge symmetry and color confinement in non-Abelian gauge theories

International Nuclear Information System (INIS)

Hata, Hiroyuki

1982-01-01

Restoration of the local gauge symmetry and its connection to color confinement is investigated in non-Abelian gauge theories with covariant gauge fixing. We consider the Noether current J sub(μ,#betta#)sup(a) of the local gauge transformation with transformation functions #betta#sup(b)(x) linear in x sub(μ); #betta#sup(b)(x) = delta sup(ab)x sub(#betta#). This current is conserved only in the physical subspace of the state vector space and in perturbation theory contains a massless pole communicating to the gauge field. We define the local gauge symmetry restoration as the disappearance of this massless ''Goldstone'' pole from J sub(μ,#betta#)sup(a). The restoration condition is obtained and it coincides exactly with the color confinement criterion proposed earlier by Kugo and Ojima. Quarks and other colored particles are shown to be confined in the local gauge symmetry restored phase by using the Ward identities of J sub(μ,#betta#)sup(a). (author)

Local observables in a landscape of infrared gauge modes

Energy Technology Data Exchange (ETDEWEB)

Thorsrud, Mikjel; Mota, David F. [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, N-0315 Oslo (Norway); Urban, Federico R. [Service de Physique Théorique, Université Libre de Bruxelles, CP225, Boulevard du Triomphe, B-1050 Brussels (Belgium)

2014-06-02

Cosmological local observables are at best statistically determined by the fundamental theory describing inflation. When the scalar inflaton is coupled uniformly to a collection of subdominant massless gauge vectors, rotational invariance is obeyed locally. However, the statistical isotropy of fluctuations is spontaneously broken by gauge modes whose wavelength exceeds our causal horizon. This leads to a landscape picture where primordial correlators depend on the position of the observer. We compute the stochastic corrections to the curvature power spectrum, show the existence of a new local observable (the shape of the quadrupole), and constrain the theory using Planck limits.

Local chemical potential, local hardness, and dual descriptors in temperature dependent chemical reactivity theory.

Science.gov (United States)

Franco-Pérez, Marco; Ayers, Paul W; Gázquez, José L; Vela, Alberto

2017-05-31

In this work we establish a new temperature dependent procedure within the grand canonical ensemble, to avoid the Dirac delta function exhibited by some of the second order chemical reactivity descriptors based on density functional theory, at a temperature of 0 K. Through the definition of a local chemical potential designed to integrate to the global temperature dependent electronic chemical potential, the local chemical hardness is expressed in terms of the derivative of this local chemical potential with respect to the average number of electrons. For the three-ground-states ensemble model, this local hardness contains a term that is equal to the one intuitively proposed by Meneses, Tiznado, Contreras and Fuentealba, which integrates to the global hardness given by the difference in the first ionization potential, I, and the electron affinity, A, at any temperature. However, in the present approach one finds an additional temperature-dependent term that introduces changes at the local level and integrates to zero. Additionally, a τ-hard dual descriptor and a τ-soft dual descriptor given in terms of the product of the global hardness and the global softness multiplied by the dual descriptor, respectively, are derived. Since all these reactivity indices are given by expressions composed of terms that correspond to products of the global properties multiplied by the electrophilic or nucleophilic Fukui functions, they may be useful for studying and comparing equivalent sites in different chemical environments.

Burst Detection and Localization using Discrete Wavelet Transform and Cross-Correlation

Directory of Open Access Journals (Sweden)

Eduardo Trutié-Carrero

2018-03-01

Full Text Available Burst in water distribution systems causes great loss of this natural resource, interrupts the water supply, damages the streets, builds and increases the transmission of infectious diseases. In this paper we propose a new algorithm that allows the detection and automatic localization of burst in water distribution systems. As for detection, the novelty is to use the wavelet correlation criterion to compute the statistical decision and compare it with a detection threshold. The novelty in the localization is to use the statistical operator cross-correlation. The algorithm was implemented in Octave and was validated with 32 signals acquired in the laboratory in a 26.7 m long steel pipe. In 16 signals burst were triggered which were detected under a false positive probability of 2 %. No false positives were present on the 16 signals where only noise was present.

Poincare invariant gravity with local supersymmetry as a gauge theory for the M-algebra

International Nuclear Information System (INIS)

Hassaine, Mokhtar; Troncoso, Ricardo; Zanelli, Jorge

2004-01-01

Here we consider a gravitational action having local Poincare invariance which is given by the dimensional continuation of the Euler density in ten dimensions. It is shown that the local supersymmetric extension of this action requires the algebra to be the maximal extension of the N=1 super-Poincare algebra. The resulting action is shown to describe a gauge theory for the M-algebra, and is not the eleven-dimensional supergravity theory of Cremmer-Julia-Scherk. The theory admits a class of vacuum solutions of the form S10-dxXd+1, where Xd+1 is a warped product of R with a d-dimensional spacetime. It is shown that a nontrivial propagator for the graviton exists only for d=4 and positive cosmological constant. Perturbations of the metric around this solution reproduce linearized General Relativity around four-dimensional de Sitter spacetime

Measuring capital market efficiency: Global and local correlations structure

Czech Academy of Sciences Publication Activity Database

Krištoufek, Ladislav; Vošvrda, Miloslav

2013-01-01

Roč. 392, č. 1 (2013), s. 184-193 ISSN 0378-4371 R&D Projects: GA ČR(CZ) GBP402/12/G097 Institutional support: RVO:67985556 Keywords : Capital market efficiency * Fractal dimension * Long-range dependence * Short-range dependence Subject RIV: AH - Economics Impact factor: 1.722, year: 2013 http://library.utia.cas.cz/separaty/2012/E/kristoufek-measuring capital market efficiency global and local correlations structure.pdf

Tensions between Scottish National Policies for onshore wind energy and local dissatisfaction - insights from regulation theory

Energy Technology Data Exchange (ETDEWEB)

Parkhill, Karen [School of Psychology, Tower Building, Cardiff University, Cardiff, (United Kingdom)

2007-09-15

Although best described as a meta theory addressing the endurance of capitalism, regulation theory can successfully be used to explore not only the economic dimensions, but also the political, socio-cultural and environmental dimensions of particular developmental strategies. Thus, it offers a framework for embedding abstract debates about social attitudes to new technologies within debates about real regulation - the economic, social and cultural relationships operating through particular places. This paper uses regulation theory and qualitative, interview-based data to analyse Scotland's drive for onshore wind energy. This approach teases out how responses to wind farms are bound up with wider debates about how rural spaces are, and should be, regulated; the tensions within and between national political objectives, local political objectives and local communities' dissatisfaction; and the connections between local actors and more formal dimensions of renewable energy policy. (Author)

Correlation functional in screened-exchange density functional theory procedures.

Science.gov (United States)

Chan, Bun; Kawashima, Yukio; Hirao, Kimihiko

2017-10-15

In the present study, we have explored several prospects for the further development of screened-exchange density functional theory (SX-DFT) procedures. Using the performance of HSE06 as our measure, we find that the use of alternative correlation functionals (as oppose to PBEc in HSE06) also yields adequate results for a diverse set of thermochemical properties. We have further examined the performance of new SX-DFT procedures (termed HSEB-type methods) that comprise the HSEx exchange and a (near-optimal) reparametrized B97c (c OS,0  = c SS,0  = 1, c OS,1  = -1.5, c OS,2  = -0.644, c SS,1  = -0.5, and c SS,2  = 1.10) correlation functionals. The different variants of HSEB all perform comparably to or slightly better than the original HSE-type procedures. These results, together with our fundamental analysis of correlation functionals, point toward various directions for advancing SX-DFT methods. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Application of time-dependent current-density-functional theory to nonlocal exchange-correlation effects in polymers

NARCIS (Netherlands)

van Faassen, M; de Boeij, PL; van Leeuwen, R; Berger, JA; Snijders, JG

2003-01-01

We provide a successful approach towards the solution of the longstanding problem of the large overestimation of the static polarizability of conjugated oligomers obtained using the local density approximation within density-functional theory. The local approximation is unable to describe the highly

Derivation of the density functional theory from the cluster expansion.

Science.gov (United States)

Hsu, J Y

2003-09-26

The density functional theory is derived from a cluster expansion by truncating the higher-order correlations in one and only one term in the kinetic energy. The formulation allows self-consistent calculation of the exchange correlation effect without imposing additional assumptions to generalize the local density approximation. The pair correlation is described as a two-body collision of bound-state electrons, and modifies the electron- electron interaction energy as well as the kinetic energy. The theory admits excited states, and has no self-interaction energy.

General theory for calculating disorder-averaged Green's function correlators within the coherent potential approximation

Science.gov (United States)

Zhou, Chenyi; Guo, Hong

2017-01-01

We report a diagrammatic method to solve the general problem of calculating configurationally averaged Green's function correlators that appear in quantum transport theory for nanostructures containing disorder. The theory treats both equilibrium and nonequilibrium quantum statistics on an equal footing. Since random impurity scattering is a problem that cannot be solved exactly in a perturbative approach, we combine our diagrammatic method with the coherent potential approximation (CPA) so that a reliable closed-form solution can be obtained. Our theory not only ensures the internal consistency of the diagrams derived at different levels of the correlators but also satisfies a set of Ward-like identities that corroborate the conserving consistency of transport calculations within the formalism. The theory is applied to calculate the quantum transport properties such as average ac conductance and transmission moments of a disordered tight-binding model, and results are numerically verified to high precision by comparing to the exact solutions obtained from enumerating all possible disorder configurations. Our formalism can be employed to predict transport properties of a wide variety of physical systems where disorder scattering is important.

A realistic model for quantum theory with a locality property

International Nuclear Information System (INIS)

Eberhard, P.H.

1987-04-01

A model reproducing the predictions of relativistic quantum theory to any desired degree of accuracy is described in this paper. It involves quantities that are independent of the observer's knowledge, and therefore can be called real, and which are defined at each point in space, and therefore can be called local in a rudimentary sense. It involves faster-than-light, but not instantaneous, action at distance

Nonlocality, Entanglement Witnesses and Supra-correlations

Science.gov (United States)

2012-04-01

quantum non-locality, non-signaling theories, Popescu-Rohrlich boxes, EPR 1. INTRODUCTION Physics imposes limits on the correlations that can be...References [1] J.S. Bell, “On the Einstein Podolsky Rosen paradox ,” Physics 1, 195 (1964). [2] B. Tsirelson, “Quantum Generalizations of Bell’s

Landscape and Local Correlates of Bee Abundance and Species Richness in Urban Gardens.

Science.gov (United States)

Quistberg, Robyn D; Bichier, Peter; Philpott, Stacy M

2016-03-31

Urban gardens may preserve biodiversity as urban population densities increase, but this strongly depends on the characteristics of the gardens and the landscapes in which they are embedded. We investigated whether local and landscape characteristics are important correlates of bee (Hymenoptera: Apiformes) abundance and species richness in urban community gardens. We worked in 19 gardens in the California central coast and sampled bees with aerial nets and pan traps. We measured local characteristics (i.e., vegetation and ground cover) and used the USGS National Land Cover Database to classify the landscape surrounding our garden study sites at 2 km scales. We classified bees according to nesting type (i.e., cavity, ground) and body size and determined which local and landscape characteristics correlate with bee community characteristics. We found 55 bee species. One landscape and several local factors correlated with differences in bee abundance and richness for all bees, cavity-nesting bees, ground-nesting bees, and different sized bees. Generally, bees were more abundant and species rich in bigger gardens, in gardens with higher floral abundance, less mulch cover, more bare ground, and with more grass. Medium bees were less abundant in sites surrounded by more medium intensity developed land within 2 km. The fact that local factors were generally more important drivers of bee abundance and richness indicates a potential for gardeners to promote bee conservation by altering local management practices. In particular, increasing floral abundance, decreasing use of mulch, and providing bare ground may promote bees in urban gardens. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Localization for random Schroedinger operators with correlated potentials

Energy Technology Data Exchange (ETDEWEB)

Von Dreifus, H [Princeton Univ., NJ (USA). Dept. of Physics; Klein, A [California Univ., Irvine (USA). Dept. of Mathematics

1991-08-01

We prove localization at high disorder or low energy for lattice Schroedinger operators with random potentials whose values at different lattice sites are correlated over large distances. The class of admissible random potentials for our multiscale analysis includes potentials with a stationary Gaussian distribution whose covariance function C(x,y) decays as vertical strokex-yvertical stroke{sup -{theta}}, where {theta}>0 can be arbitrarily small, and potentials whose probability distribution is a completely analytical Gibbs measure. The result for Gaussian potentials depends on a multivariable form of Nelson's best possible hypercontractive estimate. (orig.).

Statistical lamb wave localization based on extreme value theory

Science.gov (United States)

Harley, Joel B.

2018-04-01

Guided wave localization methods based on delay-and-sum imaging, matched field processing, and other techniques have been designed and researched to create images that locate and describe structural damage. The maximum value of these images typically represent an estimated damage location. Yet, it is often unclear if this maximum value, or any other value in the image, is a statistically significant indicator of damage. Furthermore, there are currently few, if any, approaches to assess the statistical significance of guided wave localization images. As a result, we present statistical delay-and-sum and statistical matched field processing localization methods to create statistically significant images of damage. Our framework uses constant rate of false alarm statistics and extreme value theory to detect damage with little prior information. We demonstrate our methods with in situ guided wave data from an aluminum plate to detect two 0.75 cm diameter holes. Our results show an expected improvement in statistical significance as the number of sensors increase. With seventeen sensors, both methods successfully detect damage with statistical significance.

Anderson localization and its ramifications disorder, phase coherence and electron correlations

CERN Document Server

Kettemann, S

2003-01-01

The phenomenon of localization of the electronic wave function in a random medium can be regarded as the key manifestation of quantum coherence in a condensed matter system. As one of the most remarkable phenomena in condensed matter physics discovered in the 20th century, the localization problem is an indispensable part of the theory of the quantum Hall effects and rivals superconductivity in its significance as a manifestation of quantum coherence at a macroscopic scale. The present volume, written by some of the leading experts in the field, is intended to highlight some of the recent progress in the field of localization, with particular emphasis on the effect of interactions on quantum coherence. The chapters are written in textbook style and should serve as a reliable and thorough introduction for advanced students or researchers already working in the field of mesoscopic physics.

A course on quantum field theory and local observables

Energy Technology Data Exchange (ETDEWEB)

Schroer, Bert [Frankfurt Univ., Berlin (Germany). Inst. fuer Theoretische Physik

1997-03-01

A monograph on Quantum Field Theory and Local Observables is presented, aiming to unify two presently largely disconnected branches of QFT, as follows: the standard (canonical, functional) approach which is mainly perturbative in the sense of an infinitesimal `deformation` of free fields; nonperturbative constructions of low-dimensional models as the form factor-bootstrap approach (which for the time being is limited to factorable models in d=1+1 spacetime dimensions) and the non-Lagrangian constructions of conformal chiral QFT`s

Coral reef degradation is not correlated with local human population density

Science.gov (United States)

Bruno, John F.; Valdivia, Abel

2016-07-01

The global decline of reef-building corals is understood to be due to a combination of local and global stressors. However, many reef scientists assume that local factors predominate and that isolated reefs, far from human activities, are generally healthier and more resilient. Here we show that coral reef degradation is not correlated with human population density. This suggests that local factors such as fishing and pollution are having minimal effects or that their impacts are masked by global drivers such as ocean warming. Our results also suggest that the effects of local and global stressors are antagonistic, rather than synergistic as widely assumed. These findings indicate that local management alone cannot restore coral populations or increase the resilience of reefs to large-scale impacts. They also highlight the truly global reach of anthropogenic warming and the immediate need for drastic and sustained cuts in carbon emissions.

Site-occupation embedding theory using Bethe ansatz local density approximations

Science.gov (United States)

Senjean, Bruno; Nakatani, Naoki; Tsuchiizu, Masahisa; Fromager, Emmanuel

2018-06-01

Site-occupation embedding theory (SOET) is an alternative formulation of density functional theory (DFT) for model Hamiltonians where the fully interacting Hubbard problem is mapped, in principle exactly, onto an impurity-interacting (rather than a noninteracting) one. It provides a rigorous framework for combining wave-function (or Green function)-based methods with DFT. In this work, exact expressions for the per-site energy and double occupation of the uniform Hubbard model are derived in the context of SOET. As readily seen from these derivations, the so-called bath contribution to the per-site correlation energy is, in addition to the latter, the key density functional quantity to model in SOET. Various approximations based on Bethe ansatz and perturbative solutions to the Hubbard and single-impurity Anderson models are constructed and tested on a one-dimensional ring. The self-consistent calculation of the embedded impurity wave function has been performed with the density-matrix renormalization group method. It has been shown that promising results are obtained in specific regimes of correlation and density. Possible further developments have been proposed in order to provide reliable embedding functionals and potentials.

Cooperative Localization for Multi-AUVs Based on GM-PHD Filters and Information Entropy Theory

Directory of Open Access Journals (Sweden)

Lichuan Zhang

2017-10-01

Full Text Available Cooperative localization (CL is considered a promising method for underwater localization with respect to multiple autonomous underwater vehicles (multi-AUVs. In this paper, we proposed a CL algorithm based on information entropy theory and the probability hypothesis density (PHD filter, aiming to enhance the global localization accuracy of the follower. In the proposed framework, the follower carries lower cost navigation systems, whereas the leaders carry better ones. Meanwhile, the leaders acquire the followers’ observations, including both measurements and clutter. Then, the PHD filters are utilized on the leaders and the results are communicated to the followers. The followers then perform weighted summation based on all received messages and obtain a final positioning result. Based on the information entropy theory and the PHD filter, the follower is able to acquire a precise knowledge of its position.

Coexistence in neutral theories: interplay of criticality and mild local preferences

International Nuclear Information System (INIS)

Borile, Claudio; Molina-Garcia, Daniel; Muñoz, Miguel A; Maritan, Amos

2015-01-01

Neutral theories have played a crucial and revolutionary role in fields such as population genetics and biogeography. These theories are critical by definition, in the sense that the overall growth rate of each single allele/species/type vanishes. Thus each species in a neutral model sits at the edge between invasion and extinction, allowing for the coexistence of symmetric/neutral types. However, in finite systems, mono-dominated states are ineluctably reached in relatively short times owing to demographic fluctuations, thus leaving us with an unsatisfactory framework to rationalize empirically-observed long-term coexistence. Here, we scrutinize the effect of heterogeneity in quasi-neutral theories, in which there can be a local mild preference for some of the competing species at some sites, even if the overall species symmetry is maintained. As we show here, mild biases at a small fraction of locations suffice to induce overall robust and durable species coexistence, even in regions arbitrarily far apart from the biased locations. This result stems from the long-range nature of the underlying critical bulk dynamics and has a number of implications, for example, in conservation ecology as it suggests that constructing local specific ‘sanctuaries’ for different competing species can result in global enhancement of biodiversity, even in regions arbitrarily distant from the protected refuges. (paper)

Vasoconstriction Potency Induced by Aminoamide Local Anesthetics Correlates with Lipid Solubility

Directory of Open Access Journals (Sweden)

Hui-Jin Sung

2012-01-01

Full Text Available Aminoamide local anesthetics induce vasoconstriction in vivo and in vitro. The goals of this in vitro study were to investigate the potency of local anesthetic-induced vasoconstriction and to identify the physicochemical property (octanol/buffer partition coefficient, pKa, molecular weight, or potency of local anesthetics that determines their potency in inducing isolated rat aortic ring contraction. Cumulative concentration-response curves to local anesthetics (levobupivacaine, ropivacaine, lidocaine, and mepivacaine were obtained from isolated rat aorta. Regression analyses were performed to determine the relationship between the reported physicochemical properties of local anesthetics and the local anesthetic concentration that produced 50% (ED50 of the local anesthetic-induced maximum vasoconstriction. We determined the order of potency (ED50 of vasoconstriction among local anesthetics to be levobupivacaine > ropivacaine > lidocaine > mepivacaine. The relative importance of the independent variables that affect the vasoconstriction potency is octanol/buffer partition coefficient > potency > pKa > molecular weight. The ED50 in endothelium-denuded aorta negatively correlated with the octanol/buffer partition coefficient of local anesthetics (r2=0.9563; P<0.001. The potency of the vasoconstriction in the endothelium-denuded aorta induced by local anesthetics is determined primarily by lipid solubility and, in part, by other physicochemical properties including potency and pKa.

Field theories on supermanifolds: general formalism, local supersymmetry, and the limit of global supersymmetry

International Nuclear Information System (INIS)

Bruzzo, V.

1986-01-01

This paper reports briefly on recent investigations concerning the formulation of field theories on supermanifolds. The usual formulations are unsatisfactory from a mathematical viewpoint, hence, this report. A variational theory for fields on a supermanifold is described where the action is a map between Banach spaces. The relationship between the field theory on the supermanifold and a suitably constructed field theory on space-time is also discussed. On-shell local supersymmetry are examined and the limit of global (rigid) supersymmetry is considered. A specific example is given which shows that the limit reproduces the known results

The theory precision analyse of RFM localization of satellite remote sensing imagery

Science.gov (United States)

Zhang, Jianqing; Xv, Biao

2009-11-01

The tradition method of detecting precision of Rational Function Model(RFM) is to make use of a great deal check points, and it calculates mean square error through comparing calculational coordinate with known coordinate. This method is from theory of probability, through a large number of samples to statistic estimate value of mean square error, we can think its estimate value approaches in its true when samples are well enough. This paper is from angle of survey adjustment, take law of propagation of error as the theory basis, and it calculates theory precision of RFM localization. Then take the SPOT5 three array imagery as experiment data, and the result of traditional method and narrated method in the paper are compared, while has confirmed tradition method feasible, and answered its theory precision question from the angle of survey adjustment.

General theory of intensity correlation on light scattering

International Nuclear Information System (INIS)

Villaeys, A.A.

1978-01-01

A general theory for spatio-temporal intensity correlations measurements for a scattered beam is developed. A completely quantum mechanical description for both excitation and detection set up is used. This description is essentially valid for weak incident light beams and single photon absorption processes. From a unified point of view both, stationary as well as, time resolved experiments are described. The interest for such experiments in the study of processes like resonance raman scattering and resonance fluorescence is emphasized. Also an observable coherent contribution associated to different final levels of the target-atoms or molecules is obtained a result which cannot be reached by intensity measurements

Determination of local boiling in light water reactors by correlation of the neutron noise; Determination de l'ebullition locale dans les reacteurs a eau legere par correlation du bruit neutronique

Energy Technology Data Exchange (ETDEWEB)

Zwingelstein, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1968-07-01

The power limit of swimming-pool type reactors depends on the phenomenon of the appearance of burn-out. In order to determine this limit we have attempted to detect the local boiling which usually occurs before the burn out. Local boiling has been simulated by an electrically heated plate placed in the core of the reactor Siloette. The study of local boiling, which is based on the properties of the correlation functions for the neutron noise of detectors placed in the core, shows that a privileged frequency occurs in the power spectrum of the noise. It is intended in the future to determine the influence of various parameters on this characteristic frequency. (author) [French] La limitation de la puissance des reacteurs nucleaires de type piscine est due au phenomene d'apparition de 'burn out'. Pour determiner cette limitation, nous nous sommes proposes dans ce rapport de detecter l'ebullition locale qui apparait generalement avant le 'burn out'. L'ebullition locale a ete simulee par une plaque chauffee electriquement et placee dans le coeur du reacteur SILOETTE. L'etude de l'ebullition locale, qui est basee sur les proprietes des fonctions de correlation du bruit neutronique de detecteurs places clans le coeur, fait apparaitre une frequence privilegiee dans le spectre de puissance du bruit. On envisage dans l'avenir, de determiner l'influence des divers parametres sur cette frequence caracteristique. (auteur)

Statistical electron angular correlation coefficients for atoms within the Hohenberg-Kohn-Sham theory

International Nuclear Information System (INIS)

Pathak, R.K.

1985-01-01

Statistical electron angular correlation coefficients tau = 2 2 He through 14 Si, within the Hohenberg-Kohn-Sham density-functional formalism. These are computed with use of the spectral sum rules obtained from the pseudoexcitation spectrum employing the recent formulation of the time-dependent Kohn-Sham theory due to Bartolotti. Various approximations to the exchange-correlation energy functional are used and for first-row atoms, a comparison is made with the highly accurate correlation coefficients recently obtained by Thakkar. The present tau values show closer agreement with those of Thakkar with increasing number of electrons

Quantum phase space theory for the calculation of v·j vector correlations

International Nuclear Information System (INIS)

Hall, G.E.

1995-01-01

The quantum state-counting phase space theory commonly used to describe barrierless dissociation is recast in a helicity basis to calculate photofragment v·j correlations. Counting pairs of fragment states with specific angular momentum projection numbers on the relative velocity provides a simple connection between angular momentum conservation and the v·j correlation, which is not so evident in the conventional basis for phase space state counts. The upper bound on the orbital angular momentum, l, imposed by the centrifugal barrier cannot be included simply in the helicity basis, where l is not a good quantum number. Two approaches for a quantum calculation of the v·j correlation are described to address this point. An application to the photodissociation of NCCN is consistent with recent classical phase space calculations of Cline and Klippenstein. The observed vector correlation exceeds the phase space theory prediction. The authors take this as evidence of incomplete mixing of the K states of the linear parent molecule at the transition state, corresponding to an evolution of the body-fixed projection number K into the total helicity of the fragment pair state. The average over a thermal distribution of parent angular momentum in the special case of a linear molecule does not significantly reduce the v·j correlation below that computed for total J = 0

Localization of effective actions in open superstring field theory

Science.gov (United States)

Maccaferri, Carlo; Merlano, Alberto

2018-03-01

We consider the construction of the algebraic part of D-branes tree-level effective action from Berkovits open superstring field theory. Applying this construction to the quartic potential of massless fields carrying a specific worldsheet charge, we show that the full contribution to the potential localizes at the boundary of moduli space, reducing to elementary two-point functions. As examples of this general mechanism, we show how the Yang-Mills quartic potential and the instanton effective action of a Dp/D( p - 4) system are reproduced.

The theory of magnetohydrodynamic wave generation by localized sources. I - General asymptotic theory

Science.gov (United States)

Collins, William

1989-01-01

The magnetohydrodynamic wave emission from several localized, periodic, kinematically specified fluid velocity fields are calculated using Lighthill's method for finding the far-field wave forms. The waves propagate through an isothermal and uniform plasma with a constant B field. General properties of the energy flux are illustrated with models of pulsating flux tubes and convective rolls. Interference theory from geometrical optics is used to find the direction of minimum fast-wave emission from multipole sources and slow-wave emission from discontinuous sources. The distribution of total flux in fast and slow waves varies with the ratios of the source dimensions l to the acoustic and Alfven wavelengths.

Integrated analysis on static/dynamic aeroelasticity of curved panels based on a modified local piston theory

Science.gov (United States)

Yang, Zhichun; Zhou, Jian; Gu, Yingsong

2014-10-01

A flow field modified local piston theory, which is applied to the integrated analysis on static/dynamic aeroelastic behaviors of curved panels, is proposed in this paper. The local flow field parameters used in the modification are obtained by CFD technique which has the advantage to simulate the steady flow field accurately. This flow field modified local piston theory for aerodynamic loading is applied to the analysis of static aeroelastic deformation and flutter stabilities of curved panels in hypersonic flow. In addition, comparisons are made between results obtained by using the present method and curvature modified method. It shows that when the curvature of the curved panel is relatively small, the static aeroelastic deformations and flutter stability boundaries obtained by these two methods have little difference, while for curved panels with larger curvatures, the static aeroelastic deformation obtained by the present method is larger and the flutter stability boundary is smaller compared with those obtained by the curvature modified method, and the discrepancy increases with the increasing of curvature of panels. Therefore, the existing curvature modified method is non-conservative compared to the proposed flow field modified method based on the consideration of hypersonic flight vehicle safety, and the proposed flow field modified local piston theory for curved panels enlarges the application range of piston theory.

Localization of supersymmetric field theories on non-compact hyperbolic three-manifolds

Energy Technology Data Exchange (ETDEWEB)

Assel, Benjamin; Martelli, Dario; Murthy, Sameer; Yokoyama, Daisuke [Department of Mathematics, King’s College London,The Strand, London WC2R 2LS (United Kingdom)

2017-03-17

We study supersymmetric gauge theories with an R-symmetry, defined on non-compact, hyperbolic, Riemannian three-manifolds, focusing on the case of a supersymmetry-preserving quotient of Euclidean AdS{sub 3}. We compute the exact partition function in these theories, using the method of localization, thus reducing the problem to the computation of one-loop determinants around a supersymmetric locus. We evaluate the one-loop determinants employing three different techniques: an index theorem, the method of pairing of eigenvalues, and the heat kernel method. Along the way, we discuss aspects of supersymmetry in manifolds with a conformal boundary, including supersymmetric actions and boundary conditions.

A semiclassical treatment of correlation energy for nuclear systems

International Nuclear Information System (INIS)

Nielsen, M.

1988-01-01

Starting with the separation of the many-body density operator in two parts, one describing the one-body aspects of the full density and the other containing all dynamic correlations information, the semiclassical approximation for the system correlation energy, was calculated. It is showm that, in this case, the Gaussian Wave Packets Phase Space Representation is more convenient than the Wely-Wigner Rrepresentation for the analysis of the semiclassical correlation energy. Using a phenomenological interaction, the correlation energy to the nuclear matter and some simmetric finite nucleus was calculated. The Fermi Surface Diffusivity, was also calculated. Finally, from the relation between this theory and the pertubation theory, we have done some considerations about the viability on the local densities expansion for energy functionals. (author) [pt

Group of local biholomorphisms of C/sup 1/ and conformal field theory on the operator formalism

Energy Technology Data Exchange (ETDEWEB)

Budzynski, R.J.; Klimek, S.; Sadowski, P.

1989-01-01

Motivated by the operator formulation of conformal field theory on Riemann surfaces, we study the properties of the infinite dimensional group of local biholomorphic transformations (conformal reparametrizations) of C/sup 1/ and develop elements of its representation theory.

A general theory for the construction of best-fit correlation equations for multi-dimensioned numerical data

International Nuclear Information System (INIS)

Moore, S.E.; Moffat, D.G.

2007-01-01

A general theory for the construction of best-fit correlation equations for multi-dimensioned sets of numerical data is presented. This new theory is based on the mathematics of n-dimensional surfaces and goodness-of-fit statistics. It is shown that orthogonal best-fit analytical trend lines for each of the independent parameters of the data can be used to construct an overall best-fit correlation equation that satisfies both physical boundary conditions and best-of-fit statistical measurements. Application of the theory is illustrated by fitting a three-parameter set of numerical finite-element maximum-stress data obtained earlier by Dr. Moffat for pressure vessel nozzles and/or piping system branch connections

Basic quantum theory and measurement from the viewpoint of local quantum physics

International Nuclear Information System (INIS)

Schroer, Bert

1999-04-01

Several aspects of the manifestation of the causality principle in LQP (local quantum physics) are reviewed or presented. Particular emphasis is given to those properties which are typical for LQP in the sense that they do go beyond the structure of general quantum theory and even escape the Lagrangian quantization methods of standard QFT. The most remarkable are those relating causality to the modular Tomita-Takesaki theory, since they bring in the basic concepts of antiparticles, charge superselections as well as internal and external (geometric and hidden) symmetries. (author)

Relativistic mean field theory for deformed nuclei with pairing correlations

International Nuclear Information System (INIS)

Geng, Lisheng; Toki, Hiroshi; Sugimoto, Satoru; Meng, Jie

2003-01-01

We develop a relativistic mean field (RMF) description of deformed nuclei with pairing correlations in the BCS approximation. The treatment of the pairing correlations for nuclei whose Fermi surfaces are close to the threshold of unbound states needs special attention. With this in mind, we use a delta function interaction for the pairing interaction to pick up those states whose wave functions are concentrated in the nuclear region and employ the standard BCS approximation for the single-particle states obtained from the BMF theory with deformation. We apply the RMF + BCS method to the Zr isotopes and obtain a good description of the binding energies and the nuclear radii of nuclei from the proton drip line to the neutron drip line. (author)

Structure of N = 2 superconformally invariant unitary ''minimal'' theories: Operator algebra and correlation functions

International Nuclear Information System (INIS)

Kiritsis, E.B.

1987-01-01

N = 2 superconformal-invariant theories are studied and their general structure is analyzed. The geometry of N = 2 complex superspace is developed as a tool to study the correlation functions of the theories above. The Ward identities of the global N = 2 superconformal symmetry are solved, to restrict the form of correlation functions. Advantage is taken of the existence of the degenerate operators to derive the ''fusion'' rules for the unitary minimal systems with c<1. In particular, the closure of the operator algebra for such systems is shown. The c = (1/3 minimal system is analyzed and its two-, three-, and four-point functions as well as its operator algebra are calculated explicitly

Violation of local realism with freedom of choice.

Science.gov (United States)

Scheidl, Thomas; Ursin, Rupert; Kofler, Johannes; Ramelow, Sven; Ma, Xiao-Song; Herbst, Thomas; Ratschbacher, Lothar; Fedrizzi, Alessandro; Langford, Nathan K; Jennewein, Thomas; Zeilinger, Anton

2010-11-16

Bell's theorem shows that local realistic theories place strong restrictions on observable correlations between different systems, giving rise to Bell's inequality which can be violated in experiments using entangled quantum states. Bell's theorem is based on the assumptions of realism, locality, and the freedom to choose between measurement settings. In experimental tests, "loopholes" arise which allow observed violations to still be explained by local realistic theories. Violating Bell's inequality while simultaneously closing all such loopholes is one of the most significant still open challenges in fundamental physics today. In this paper, we present an experiment that violates Bell's inequality while simultaneously closing the locality loophole and addressing the freedom-of-choice loophole, also closing the latter within a reasonable set of assumptions. We also explain that the locality and freedom-of-choice loopholes can be closed only within nondeterminism, i.e., in the context of stochastic local realism.

A new methodology of spatial cross-correlation analysis.

Science.gov (United States)

Chen, Yanguang

2015-01-01

Spatial correlation modeling comprises both spatial autocorrelation and spatial cross-correlation processes. The spatial autocorrelation theory has been well-developed. It is necessary to advance the method of spatial cross-correlation analysis to supplement the autocorrelation analysis. This paper presents a set of models and analytical procedures for spatial cross-correlation analysis. By analogy with Moran's index newly expressed in a spatial quadratic form, a theoretical framework is derived for geographical cross-correlation modeling. First, two sets of spatial cross-correlation coefficients are defined, including a global spatial cross-correlation coefficient and local spatial cross-correlation coefficients. Second, a pair of scatterplots of spatial cross-correlation is proposed, and the plots can be used to visually reveal the causality behind spatial systems. Based on the global cross-correlation coefficient, Pearson's correlation coefficient can be decomposed into two parts: direct correlation (partial correlation) and indirect correlation (spatial cross-correlation). As an example, the methodology is applied to the relationships between China's urbanization and economic development to illustrate how to model spatial cross-correlation phenomena. This study is an introduction to developing the theory of spatial cross-correlation, and future geographical spatial analysis might benefit from these models and indexes.

Local wavelet correlation: applicationto timing analysis of multi-satellite CLUSTER data

Directory of Open Access Journals (Sweden)

J. Soucek

2004-12-01

Full Text Available Multi-spacecraft space observations, such as those of CLUSTER, can be used to infer information about local plasma structures by exploiting the timing differences between subsequent encounters of these structures by individual satellites. We introduce a novel wavelet-based technique, the Local Wavelet Correlation (LWC, which allows one to match the corresponding signatures of large-scale structures in the data from multiple spacecraft and determine the relative time shifts between the crossings. The LWC is especially suitable for analysis of strongly non-stationary time series, where it enables one to estimate the time lags in a more robust and systematic way than ordinary cross-correlation techniques. The technique, together with its properties and some examples of its application to timing analysis of bow shock and magnetopause crossing observed by CLUSTER, are presented. We also compare the performance and reliability of the technique with classical discontinuity analysis methods. Key words. Radio science (signal processing – Space plasma physics (discontinuities; instruments and techniques

ICOM-ICTOP 14 October 2015 Workshop : Applying Global Theory to Local Practice

NARCIS (Netherlands)

Ariese, C.E.; Con, Aguilar E.O.; Martin, J.A.

2015-01-01

This workshop is connected to the presentation ‘Transforming global theory to local practice: Case studies from museums and education in the Caribbean’ and provides a practical and creative exercise for participants. The objective of the workshop is to support participants in exploring how to apply

Quantumness and the role of locality on quantum correlations

Science.gov (United States)

Bellomo, G.; Plastino, A.; Plastino, A. R.

2016-06-01

Quantum correlations in a physical system are usually studied with respect to a unique and fixed decomposition of the system into subsystems, without fully exploiting the rich structure of the state space. Here, we show several examples in which the consideration of different ways to decompose a physical system enhances the quantum resources and accounts for a more flexible definition of quantumness measures. Furthermore, we give a different perspective regarding how to reassess the fact that local operations play a key role in general quantumness measures that go beyond entanglement—as discordlike ones. We propose a family of measures to quantify the maximum quantumness of a given state. For the discord-based case, we present some analytical results for 2 ×d -dimensional states. Applying our definition to low-dimensional bipartite states, we show that different behaviors can be reported for separable and entangled states vis-à-vis those corresponding to the usual measures of quantum correlations. We show that there is a close link between our proposal and the criterion to witness quantum correlations based on the rank of the correlation matrix, proposed by Dakić, Vedral, and Brukner [Phys. Rev. Lett. 105, 190502 (2010), 10.1103/PhysRevLett.105.190502].

Towards a large deviation theory for strongly correlated systems

International Nuclear Information System (INIS)

Ruiz, Guiomar; Tsallis, Constantino

2012-01-01

A large-deviation connection of statistical mechanics is provided by N independent binary variables, the (N→∞) limit yielding Gaussian distributions. The probability of n≠N/2 out of N throws is governed by e −Nr , r related to the entropy. Large deviations for a strong correlated model characterized by indices (Q,γ) are studied, the (N→∞) limit yielding Q-Gaussians (Q→1 recovers a Gaussian). Its large deviations are governed by e q −Nr q (∝1/N 1/(q−1) , q>1), q=(Q−1)/(γ[3−Q])+1. This illustration opens the door towards a large-deviation foundation of nonextensive statistical mechanics. -- Highlights: ► We introduce the formalism of relative entropy for a single random binary variable and its q-generalization. ► We study a model of N strongly correlated binary random variables and their large-deviation probabilities. ► Large-deviation probability of strongly correlated model exhibits a q-exponential decay whose argument is proportional to N, as extensivity requires. ► Our results point to a q-generalized large deviation theory and suggest a large-deviation foundation of nonextensive statistical mechanics.

Calculation of strained BaTiO3 with different exchange correlation functionals examined with criterion by Ginzburg-Landau theory, uncovering expressions by crystallographic parameters

Science.gov (United States)

Watanabe, Yukio

2018-05-01

In the calculations of tetragonal BaTiO3, some exchange-correlation (XC) energy functionals such as local density approximation (LDA) have shown good agreement with experiments at room temperature (RT), e.g., spontaneous polarization (PS), and superiority compared with other XC functionals. This is due to the error compensation of the RT effect and, hence, will be ineffective in the heavily strained case such as domain boundaries. Here, ferroelectrics under large strain at RT are approximated as those at 0 K because the strain effect surpasses the RT effects. To find effective XC energy functionals for strained BaTiO3, we propose a new comparison, i.e., a criterion. This criterion is the properties at 0 K given by the Ginzburg-Landau (GL) theory because GL theory is a thermodynamic description of experiments working under the same symmetry-constraints as ab initio calculations. With this criterion, we examine LDA, generalized gradient approximations (GGA), meta-GGA, meta-GGA + local correlation potential (U), and hybrid functionals, which reveals the high accuracy of some XC functionals superior to XC functionals that have been regarded as accurate. This result is examined directly by the calculations of homogenously strained tetragonal BaTiO3, confirming the validity of the new criterion. In addition, the data points of theoretical PS vs. certain crystallographic parameters calculated with different XC functionals are found to lie on a single curve, despite their wide variations. Regarding these theoretical data points as corresponding to the experimental results, analytical expressions of the local PS using crystallographic parameters are uncovered. These expressions show the primary origin of BaTiO3 ferroelectricity as oxygen displacements. Elastic compliance and electrostrictive coefficients are estimated. For the comparison of strained results, we show that the effective critical temperature TC under strain 1000 K from an approximate method combining ab initio

Small-angle scattering theory revisited: Photocurrent and spatial localization

DEFF Research Database (Denmark)

Basse, N.P.; Zoletnik, S.; Michelsen, Poul

2005-01-01

In this paper theory on collective scattering measurements of electron density fluctuations in fusion plasmas is revisited. We present the first full derivation of the expression for the photocurrent beginning at the basic scattering concepts. Thereafter we derive detailed expressions for the auto......- and crosspower spectra obtained from measurements. These are discussed and simple simulations made to elucidate the physical meaning of the findings. In this context, the known methods of obtaining spatial localization are discussed and appraised. Where actual numbers are applied, we utilize quantities from two...

Diagrammatic analysis of correlations in polymer fluids: Cluster diagrams via Edwards' field theory

International Nuclear Information System (INIS)

Morse, David C.

2006-01-01

Edwards' functional integral approach to the statistical mechanics of polymer liquids is amenable to a diagrammatic analysis in which free energies and correlation functions are expanded as infinite sums of Feynman diagrams. This analysis is shown to lead naturally to a perturbative cluster expansion that is closely related to the Mayer cluster expansion developed for molecular liquids by Chandler and co-workers. Expansion of the functional integral representation of the grand-canonical partition function yields a perturbation theory in which all quantities of interest are expressed as functionals of a monomer-monomer pair potential, as functionals of intramolecular correlation functions of non-interacting molecules, and as functions of molecular activities. In different variants of the theory, the pair potential may be either a bare or a screened potential. A series of topological reductions yields a renormalized diagrammatic expansion in which collective correlation functions are instead expressed diagrammatically as functionals of the true single-molecule correlation functions in the interacting fluid, and as functions of molecular number density. Similar renormalized expansions are also obtained for a collective Ornstein-Zernicke direct correlation function, and for intramolecular correlation functions. A concise discussion is given of the corresponding Mayer cluster expansion, and of the relationship between the Mayer and perturbative cluster expansions for liquids of flexible molecules. The application of the perturbative cluster expansion to coarse-grained models of dense multi-component polymer liquids is discussed, and a justification is given for the use of a loop expansion. As an example, the formalism is used to derive a new expression for the wave-number dependent direct correlation function and recover known expressions for the intramolecular two-point correlation function to first-order in a renormalized loop expansion for coarse-grained models of

Shot noise as a probe of spin-correlated transport through single atoms

Science.gov (United States)

Pradhan, S.; Fransson, J.

2018-03-01

We address the shot noise in the tunneling current through a local spin, pertaining to recent experiments on magnetic adatoms and single molecular magnets. We show that both uncorrelated and spin-correlated scattering processes contribute vitally to the noise spectrum. The spin-correlated scattering processes provide an additional contribution to the Landauer-Büttiker shot noise expression, accounting for correlations between the tunneling electrons and the localized spin moment. By calculating the Fano factor, we show that both super- and sub-Poissonian shot noise can be described within our approach. Our theory provides transparent insights into noise spectroscopy, consistent with recent experiments using local probing techniques on magnetic atoms.

Non-locality of non-Abelian anyons

International Nuclear Information System (INIS)

Brennen, G K; Iblisdir, S; Pachos, J K; Slingerland, J K

2009-01-01

Entangled states of quantum systems can give rise to measurement correlations of separated observers that cannot be described by local hidden variable theories. Usually, it is assumed that entanglement between particles is generated due to some distance-dependent interaction. Yet anyonic particles in two dimensions have a nontrivial interaction that is purely topological in nature. In other words, it does not depend on the distance between two particles, but rather on their exchange history. The information encoded in anyons is inherently non-local even in the single subsystem level making the treatment of anyons non-conventional. We describe a protocol to reveal the non-locality of anyons in terms of correlations in the outcomes of measurements in two separated regions. This gives a clear operational measure of non-locality for anyonic states and it opens up the possibility to test Bell inequalities in quantum Hall liquids or spin lattices.

Non-locality of non-Abelian anyons

Science.gov (United States)

Brennen, G. K.; Iblisdir, S.; Pachos, J. K.; Slingerland, J. K.

2009-10-01

Entangled states of quantum systems can give rise to measurement correlations of separated observers that cannot be described by local hidden variable theories. Usually, it is assumed that entanglement between particles is generated due to some distance-dependent interaction. Yet anyonic particles in two dimensions have a nontrivial interaction that is purely topological in nature. In other words, it does not depend on the distance between two particles, but rather on their exchange history. The information encoded in anyons is inherently non-local even in the single subsystem level making the treatment of anyons non-conventional. We describe a protocol to reveal the non-locality of anyons in terms of correlations in the outcomes of measurements in two separated regions. This gives a clear operational measure of non-locality for anyonic states and it opens up the possibility to test Bell inequalities in quantum Hall liquids or spin lattices.

Theory of mind in schizophrenia: correlation with clinical symptomatology, emotional recognition and ward behavior.

Science.gov (United States)

Lee, Woo Kyeong; Kim, Yong Kyu

2013-09-01

Several studies have suggested the presence of a theory of mind (ToM) deficit in schizophrenic disorders. This study examined the relationship of emotion recognition, theory of mind, and ward behavior in patients with schizophrenia. Fifty-five patients with chronic schizophrenia completed measures of emotion recognition, ToM, intelligence, Positive and Negative Syndrome Scale (PANSS) and Nurse's Observation Scale for Inpatient Evaluation (NOSIE). Theory of mind sum score correlated significantly with IQ, emotion recognition, and ward behavior. Ward behavior was linked to the duration of the illness, and even more so to theory of mind deficits. Theory of mind contributed a significant proportion of the amount of variance to explain social behavior on the ward. Considering our study results, impaired theory of mind contributes significantly to the understanding of social competence in patients with schizophrenia. Copyright © 2012 Wiley Publishing Asia Pty Ltd.

Electronic correlations in insulators, metals and superconductors

Energy Technology Data Exchange (ETDEWEB)

Sentef, Michael Andreas

2010-12-03

In this thesis dynamical mean-field methods in combination with a continuous-time quantum Monte Carlo impurity solver are used to study selected open problems of condensed matter theory. These problems comprise the effect of correlations and their quantification in covalent band insulators, non-local correlation effects and their intriguing consequences in frustrated two-dimensional systems, and a phenomenological approach to investigate temperature-dependent transport in graphene in the presence of disorder. (orig.)

Electronic correlations in insulators, metals and superconductors

International Nuclear Information System (INIS)

Sentef, Michael Andreas

2010-01-01

In this thesis dynamical mean-field methods in combination with a continuous-time quantum Monte Carlo impurity solver are used to study selected open problems of condensed matter theory. These problems comprise the effect of correlations and their quantification in covalent band insulators, non-local correlation effects and their intriguing consequences in frustrated two-dimensional systems, and a phenomenological approach to investigate temperature-dependent transport in graphene in the presence of disorder. (orig.)

Spontaneous breaking of N=2 to N=1 in rigid and local supersymmetric theories

CERN Document Server

Ferrara, Sergio; Porrati, Massimo

1996-01-01

We analyze the relation between rigid and local supersymmetric N=2 field theories, when half of the supersymmetries are spontaneously broken. In particular, we show that the recently found partial supersymmety breaking induced by electric and magnetic Fayet-Iliopoulos terms in rigid theories can be obtained by a suitable flat limit of previously constructed N=2 supergravity models with partial super-Higgs in the observable sector.

From plane waves to local Gaussians for the simulation of correlated periodic systems

International Nuclear Information System (INIS)

Booth, George H.; Tsatsoulis, Theodoros; Grüneis, Andreas; Chan, Garnet Kin-Lic

2016-01-01

We present a simple, robust, and black-box approach to the implementation and use of local, periodic, atom-centered Gaussian basis functions within a plane wave code, in a computationally efficient manner. The procedure outlined is based on the representation of the Gaussians within a finite bandwidth by their underlying plane wave coefficients. The core region is handled within the projected augment wave framework, by pseudizing the Gaussian functions within a cutoff radius around each nucleus, smoothing the functions so that they are faithfully represented by a plane wave basis with only moderate kinetic energy cutoff. To mitigate the effects of the basis set superposition error and incompleteness at the mean-field level introduced by the Gaussian basis, we also propose a hybrid approach, whereby the complete occupied space is first converged within a large plane wave basis, and the Gaussian basis used to construct a complementary virtual space for the application of correlated methods. We demonstrate that these pseudized Gaussians yield compact and systematically improvable spaces with an accuracy comparable to their non-pseudized Gaussian counterparts. A key advantage of the described method is its ability to efficiently capture and describe electronic correlation effects of weakly bound and low-dimensional systems, where plane waves are not sufficiently compact or able to be truncated without unphysical artifacts. We investigate the accuracy of the pseudized Gaussians for the water dimer interaction, neon solid, and water adsorption on a LiH surface, at the level of second-order Møller–Plesset perturbation theory.

From plane waves to local Gaussians for the simulation of correlated periodic systems

Energy Technology Data Exchange (ETDEWEB)

Booth, George H., E-mail: george.booth@kcl.ac.uk [Department of Physics, King’s College London, Strand, London WC2R 2LS (United Kingdom); Tsatsoulis, Theodoros; Grüneis, Andreas, E-mail: a.grueneis@fkf.mpg.de [Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart (Germany); Chan, Garnet Kin-Lic [Frick Laboratory, Department of Chemistry, Princeton University, Princeton, New Jersey 08544 (United States)

2016-08-28

We present a simple, robust, and black-box approach to the implementation and use of local, periodic, atom-centered Gaussian basis functions within a plane wave code, in a computationally efficient manner. The procedure outlined is based on the representation of the Gaussians within a finite bandwidth by their underlying plane wave coefficients. The core region is handled within the projected augment wave framework, by pseudizing the Gaussian functions within a cutoff radius around each nucleus, smoothing the functions so that they are faithfully represented by a plane wave basis with only moderate kinetic energy cutoff. To mitigate the effects of the basis set superposition error and incompleteness at the mean-field level introduced by the Gaussian basis, we also propose a hybrid approach, whereby the complete occupied space is first converged within a large plane wave basis, and the Gaussian basis used to construct a complementary virtual space for the application of correlated methods. We demonstrate that these pseudized Gaussians yield compact and systematically improvable spaces with an accuracy comparable to their non-pseudized Gaussian counterparts. A key advantage of the described method is its ability to efficiently capture and describe electronic correlation effects of weakly bound and low-dimensional systems, where plane waves are not sufficiently compact or able to be truncated without unphysical artifacts. We investigate the accuracy of the pseudized Gaussians for the water dimer interaction, neon solid, and water adsorption on a LiH surface, at the level of second-order Møller–Plesset perturbation theory.

Extending the random-phase approximation for electronic correlation energies: the renormalized adiabatic local density approximation

DEFF Research Database (Denmark)

Olsen, Thomas; Thygesen, Kristian S.

2012-01-01

The adiabatic connection fluctuation-dissipation theorem with the random phase approximation (RPA) has recently been applied with success to obtain correlation energies of a variety of chemical and solid state systems. The main merit of this approach is the improved description of dispersive forces...... while chemical bond strengths and absolute correlation energies are systematically underestimated. In this work we extend the RPA by including a parameter-free renormalized version of the adiabatic local-density (ALDA) exchange-correlation kernel. The renormalization consists of a (local) truncation...... of the ALDA kernel for wave vectors q > 2kF, which is found to yield excellent results for the homogeneous electron gas. In addition, the kernel significantly improves both the absolute correlation energies and atomization energies of small molecules over RPA and ALDA. The renormalization can...

Lattice relaxation theory of localized excitations in quasi-one-dimensional systems

International Nuclear Information System (INIS)

Wang Chuilin; Su Zhaobin; Yu Lu.

1993-04-01

The lattice relaxation theory developed earlier by Su and Yu for solitons and polarons in conducting polymers is applied to systems with both electron-phonon and electron-electron interactions, described by a single band Peierls-Hubbard model. The localized excitations in the competing bond-order-wave (BOW), charge-density-wave (CDW) and spin-density-wave (SDW) systems show interesting new features in their dynamics. In particular, a non-monotonic dependence of the relaxation rate on the coupling strength is predicted from the theory. The possible connection of this effect with photo-luminescence experiments is discussed. Similar phenomena may occur in other quasi-one-dimensional systems as well. (author). 21 refs, 4 figs

The Hartree product and the description of local and global quantities in atomic systems: A study within Kohn-Sham theory

International Nuclear Information System (INIS)

Garza, Jorge; Nichols, Jeffrey A.; Dixon, David A.

2000-01-01

The Hartree product is analyzed in the context of Kohn-Sham theory. The differential equations that emerge from this theory are solved with the optimized effective potential using the Krieger, Li, and Iafrate approximation, in order to get a local potential as required by the ordinary Kohn-Sham procedure. Because the diagonal terms of the exact exchange energy are included in Hartree theory, it is self-interaction free and the exchange potential has the proper asymptotic behavior. We have examined the impact of this correct asymptotic behavior on local and global properties using this simple model to approximate the exchange energy. Local quantities, such as the exchange potential and the average local electrostatic potential are used to examine whether the shell structure in an atom is revealed by this theory. Global quantities, such as the highest occupied orbital energy (related to the ionization potential) and the exchange energy are also calculated. These quantities are contrasted with those obtained from calculations with the local density approximation, the generalized gradient approximation, and the self-interaction correction approach proposed by Perdew and Zunger. We conclude that the main characteristics in an atomic system are preserved with the Hartree theory. In particular, the behavior of the exchange potential obtained in this theory is similar to those obtained within other Kohn-Sham approximations. (c) 2000 American Institute of Physics

Analysis of correlation functions in Toda theory and the Alday-Gaiotto-Tachikawa-Wyllard relation for SU(3) quiver

International Nuclear Information System (INIS)

Kanno, Shoichi; Matsuo, Yutaka; Shiba, Shotaro

2010-01-01

We give some evidences of the Alday-Gaiotto-Tachikawa-Wyllard relation between SU(3) quiver gauge theories and A 2 Toda theory. In particular, we derive the explicit form of 5-point correlation functions in the lower orders and confirm the agreement with Nekrasov's partition function for SU(3)xSU(3) quiver gauge theory. The algorithm to derive the correlation functions can be applied to a general n-point function in A 2 Toda theory, which will be useful to establish the relation for more generic quivers. Partial analysis is also given for the SU(3)xSU(2) case, and we comment on some technical issues that need clarification before establishing the relation.

Nuclear many-body correlation dynamics--a nonperturbative approach in quantum many-body theory

International Nuclear Information System (INIS)

Wang Shunjin

1996-01-01

Based on the experimental results and theoretical experience in nuclear physics, the article has explored the basic physical ideas and theoretical methods in nuclear and quantum many-body correlation dynamics. The main theoretical results and important applications are introduced briefly. The paper addresses the fundamental ingredients and physical interpretation of theoretical results in a comprehensive way. Recent new results about correlation dynamics in quantum field theories are also presented. The perspectives of further application are viewed. (91 refs.)

Supergauge symmetry in local quantum field theory

International Nuclear Information System (INIS)

Ferrara, S.

1974-01-01

The extension of supergauge symmetry to four-dimensional space-time allows to investigate the possible role of this symmetry in conventional local quantum field theory. The supergauge algebra is obtained by adding to the conformal group of space-time two Majorana spinor generators and the chiral charge. The commutation properties of the algebra are used to derive the most general form of the superfield. This field contains two Majorana spinors, two scalar fields, a chiral doublet, and a real vector field called the vector superfield. The covariant derivatives defined, together with the scalar and vector multiplets are the basic ingredients used in order to build up supergauge symmetric Lagrangians. It is shown that the only possible fields which can be considered as supergauge invariant Lagrangians are the F and D components of the scalar and vector multiplets respectively

Local models of Gauge Mediated Supersymmetry Breaking in String Theory

CERN Document Server

Garcia-Etxebarria, I; Uranga, Angel M; Garcia-Etxebarria, Inaki; Saad, Fouad; Uranga, Angel M.

2006-01-01

We describe local Calabi-Yau geometries with two isolated singularities at which systems of D3- and D7-branes are located, leading to chiral sectors corresponding to a semi-realistic visible sector and a hidden sector with dynamical supersymmetry breaking. We provide explicit models with a 3-family MSSM-like visible sector, and a hidden sector breaking supersymmetry at a meta-stable minimum. For singularities separated by a distance smaller than the string scale, this construction leads to a simple realization of gauge mediated supersymmetry breaking in string theory. The models are simple enough to allow the explicit computation of the massive messenger sector, using dimer techniques for branes at singularities. The local character of the configurations makes manifest the UV insensitivity of the supersymmetry breaking mediation.

Correlation functions with fusion-channel multiplicity in W3 Toda field theory

International Nuclear Information System (INIS)

Belavin, Vladimir; Estienne, Benoit; Foda, Omar; Santachiara, Raoul

2016-01-01

Current studies of W N Toda field theory focus on correlation functions such that the W N highest-weight representations in the fusion channels are multiplicity-free. In this work, we study W 3 Toda 4-point functions with multiplicity in the fusion channel. The conformal blocks of these 4-point functions involve matrix elements of a fully-degenerate primary field with a highest-weight in the adjoint representation of sl 3 , and a fully-degenerate primary field with a highest-weight in the fundamental representation of sl 3 . We show that, when the fusion rules do not involve multiplicities, the matrix elements of the fully-degenerate adjoint field, between two arbitrary descendant states, can be computed explicitly, on equal footing with the matrix elements of the semi-degenerate fundamental field. Using null-state conditions, we obtain a fourth-order Fuchsian differential equation for the conformal blocks. Using Okubo theory, we show that, due to the presence of multiplicities, this differential equation belongs to a class of Fuchsian equations that is different from those that have appeared so far in W N theories. We solve this equation, compute its monodromy group, and construct the monodromy-invariant correlation functions. This computation shows in detail how the ambiguities that are caused by the presence of multiplicities are fixed by requiring monodromy-invariance.

Dynamical local field, compressibility, and frequency sum rules for quasiparticles

International Nuclear Information System (INIS)

Morawetz, Klaus

2002-01-01

The finite temperature dynamical response function including the dynamical local field is derived within a quasiparticle picture for interacting one-, two-, and three-dimensional Fermi systems. The correlations are assumed to be given by a density-dependent effective mass, quasiparticle energy shift, and relaxation time. The latter one describes disorder or collisional effects. This parametrization of correlations includes local-density functionals as a special case and is therefore applicable for density-functional theories. With a single static local field, the third-order frequency sum rule can be fulfilled simultaneously with the compressibility sum rule by relating the effective mass and quasiparticle energy shift to the structure function or pair-correlation function. Consequently, solely local-density functionals without taking into account effective masses cannot fulfill both sum rules simultaneously with a static local field. The comparison to the Monte Carlo data seems to support such a quasiparticle picture

Local gauge coupling running in supersymmetric gauge theories on orbifolds

International Nuclear Information System (INIS)

Hillenbach, M.

2007-01-01

By extending Feynman's path integral calculus to fields which respect orbifold boundary conditions we provide a straightforward and convenient framework for loop calculations on orbifolds. We take advantage of this general method to investigate supersymmetric Abelian and non-Abelian gauge theories in five, six and ten dimensions where the extra dimensions are compactified on an orbifold. We consider hyper and gauge multiplets in the bulk and calculate the renormalization of the gauge kinetic term which in particular allows us to determine the gauge coupling running. The renormalization of the higher dimensional theories in orbifold spacetimes exhibits a rich structure with three principal effects: Besides the ordinary renormalization of the bulk gauge kinetic term the loop effects may require the introduction of both localized gauge kinetic terms at the fixed points/planes of the orbifold and higher dimensional operators. (orig.)

Local gauge coupling running in supersymmetric gauge theories on orbifolds

Energy Technology Data Exchange (ETDEWEB)

Hillenbach, M.

2007-11-21

By extending Feynman's path integral calculus to fields which respect orbifold boundary conditions we provide a straightforward and convenient framework for loop calculations on orbifolds. We take advantage of this general method to investigate supersymmetric Abelian and non-Abelian gauge theories in five, six and ten dimensions where the extra dimensions are compactified on an orbifold. We consider hyper and gauge multiplets in the bulk and calculate the renormalization of the gauge kinetic term which in particular allows us to determine the gauge coupling running. The renormalization of the higher dimensional theories in orbifold spacetimes exhibits a rich structure with three principal effects: Besides the ordinary renormalization of the bulk gauge kinetic term the loop effects may require the introduction of both localized gauge kinetic terms at the fixed points/planes of the orbifold and higher dimensional operators. (orig.)

Modeling Correlation Effects in Nickelates with Slave Particles

Science.gov (United States)

Georgescu, Alexandru Bogdan; Ismail-Beigi, Sohrab

Nickelate interfaces display interesting electronic properties including orbital ordering similar to that of cuprate superconductors and thickness dependent metal-insulator transitions. One-particle band theory calculations do not include dynamic localized correlation effects on the nickel sites and thus often incorrectly predict metallic systems or incorrect ARPES spectra. Building on two previous successful slave-particle treatments of local correlations, we present a generalized slave-particle method that includes prior models and allows us to produce new intermediate models. The computational efficiency of these slave-boson methods means that one can readily study correlation effects in complex heterostructures. We show some predictions of these methods for the electronic structure of bulk and thin film nickelates. Work supported by NSF Grant MRSEC DMR-1119826.

On strong-coupling correlation functions of circular Wilson loops and local operators

International Nuclear Information System (INIS)

Alday, Luis F; Tseytlin, Arkady A

2011-01-01

Motivated by the problem of understanding 3-point correlation functions of gauge-invariant operators in N=4 super Yang-Mills theory we consider correlators involving Wilson loops and a 'light' operator with fixed quantum numbers. At leading order in the strong-coupling expansion such correlators are given by the 'light' vertex operator evaluated on a semiclassical string world surface ending on the corresponding loops at the boundary of AdS 5 x S 5 . We study in detail the example of a correlator of two concentric circular Wilson loops and a dilaton vertex operator. The resulting expression is given by an integral of combinations of elliptic functions and can be computed analytically in some special limits. We also consider a generalization of the minimal surface ending on two circles to the case of non-zero angular momentum J in S 5 and discuss a special limit when one of the Wilson loops is effectively replaced by a 'heavy' operator with charge J. (paper)

Density-functional theory in one dimension for contact-interacting fermions

International Nuclear Information System (INIS)

Magyar, R.J.; Burke, K.

2004-01-01

A density-functional theory is developed for fermions in one dimension, interacting via a δ function. Such systems provide a natural testing ground for questions of principle, as the local-density approximation should be highly accurate since for this interaction type the exchange contribution to the local-density approximation is intrinsically self-interaction-free. The exact-exchange contribution to the total energy is a local functional of the density. A local-density approximation for correlation is obtained using perturbation theory and Bethe ansatz results for the one-dimensional contact-interacting uniform Fermi gas. The ground-state energies are calculated for two finite systems, the analogs of helium and of Hooke's atom. The local-density approximation is shown to be excellent as expected

Random matrix theory analysis of cross-correlations in the US stock market: Evidence from Pearson’s correlation coefficient and detrended cross-correlation coefficient

Science.gov (United States)

Wang, Gang-Jin; Xie, Chi; Chen, Shou; Yang, Jiao-Jiao; Yang, Ming-Yan

2013-09-01

In this study, we first build two empirical cross-correlation matrices in the US stock market by two different methods, namely the Pearson’s correlation coefficient and the detrended cross-correlation coefficient (DCCA coefficient). Then, combining the two matrices with the method of random matrix theory (RMT), we mainly investigate the statistical properties of cross-correlations in the US stock market. We choose the daily closing prices of 462 constituent stocks of S&P 500 index as the research objects and select the sample data from January 3, 2005 to August 31, 2012. In the empirical analysis, we examine the statistical properties of cross-correlation coefficients, the distribution of eigenvalues, the distribution of eigenvector components, and the inverse participation ratio. From the two methods, we find some new results of the cross-correlations in the US stock market in our study, which are different from the conclusions reached by previous studies. The empirical cross-correlation matrices constructed by the DCCA coefficient show several interesting properties at different time scales in the US stock market, which are useful to the risk management and optimal portfolio selection, especially to the diversity of the asset portfolio. It will be an interesting and meaningful work to find the theoretical eigenvalue distribution of a completely random matrix R for the DCCA coefficient because it does not obey the Marčenko-Pastur distribution.

Vacuum correlation functions for ghost superfields and multiloop amplitudes in the theory of closed superstrings

International Nuclear Information System (INIS)

Danilov, G.S.

1995-01-01

A new formalism for ghosts on complex (1 bar 1) supermanifolds of genus n > 1 is discussed in superstring theory. In this formalism, vacuum correlation functions for ghost superfields differ substantially from correlation functions discussed earlier. In particular, the new correlation functions do not have unphysical poles. Among other things, these correlation functions take into account contributions to partition functions from the phase space of modular forms and from zero modes of ghosts. The above correlation functions, obtained for all even spinor structures, can be used to evaluate partition functions from equations that are nothing but Ward identities. 21 refs

Comments on the locality in density-functional theory

International Nuclear Information System (INIS)

Lindgren, Ingvar; Salomonson, Sten

2003-01-01

The 'locality hypothesis' in density-functional theory (DFT), implying that the functional derivative is equivalent to a multiplicative local function, forms the basis of models of Kohn-Sham type. This has been generally accepted by the community since the advent of the model, and has later been formally proved for a large class of functionals. The hypothesis has recently been questioned by Nesbet [Phys. Rev. A 58, R12 (1998) and Phys. Rev. A 65, 010502 (2001)], who claims that it fails for the kinetic-energy functional for a system with more than two noninteracting electrons with a nondegenerate ground state. This conclusion has been questioned by Gal [Phys. Rev. A 62, 044501 (2000)] and by Holas and March [Phys. Rev. A 64, 016501 (2001)]. We claim that the arguments of Nesbet are incorrect, since the orbital functional used for the kinetic energy is not a unique functional of the total density in the domain of unnormalized orbitals. We have demonstrated that with a proper definition of the kinetic energy, which is a unique density functional also in the unnormalized region, the derivative can be represented by a single local multiplicative function for all v-representable densities. Therefore, we consider the controversy connected with the issue raised by Nesbet as resolved. We believe that the proof of the differentiability given here can be extended to larger groups of DFT functionals, and works along these lines are in progress

A theory of local and global processes which affect solar wind electrons. 2. Experimental support

International Nuclear Information System (INIS)

Scudder, J.D.; Olbert, S.

1979-05-01

The microscopic characteristics of the Coulomb cross section show that there are three natural subpopulations for plasma electrons: the subthermals; the transthermals; and the extrathermals. Data from three experimental groups on three different spacecraft in the interplanetary medium over a radial range are presented to support the five interrelations projected between solar wind electron properties and changes in the interplanetary medium: (1) subthermals respond primarily to local changes (compression and rarefactions) in stream dynamics; (2) the extrathermal fraction of the ambient electron density should be anti-correlated with the asymptotic bulk speed; (3) the extrathermal 'temperature' should be anti-correlated with the local wind speed at 1 AU; (4) the heat flux carried by electrons should be anti-correlated with the local bulk speed; and (5) the extrathermal differential 'temperature' should be nearly independent of radius within 1 AU

Expectation values of local fields for a two-parameter family of integrable models and related perturbed conformal field theories

International Nuclear Information System (INIS)

Baseilhac, P.; Fateev, V.A.

1998-01-01

We calculate the vacuum expectation values of local fields for the two-parameter family of integrable field theories introduced and studied by Fateev (1996). Using this result we propose an explicit expression for the vacuum expectation values of local operators in parafermionic sine-Gordon models and in integrable perturbed SU(2) coset conformal field theories. (orig.)

A New Methodology of Spatial Cross-Correlation Analysis

Science.gov (United States)

Chen, Yanguang

2015-01-01

Spatial correlation modeling comprises both spatial autocorrelation and spatial cross-correlation processes. The spatial autocorrelation theory has been well-developed. It is necessary to advance the method of spatial cross-correlation analysis to supplement the autocorrelation analysis. This paper presents a set of models and analytical procedures for spatial cross-correlation analysis. By analogy with Moran’s index newly expressed in a spatial quadratic form, a theoretical framework is derived for geographical cross-correlation modeling. First, two sets of spatial cross-correlation coefficients are defined, including a global spatial cross-correlation coefficient and local spatial cross-correlation coefficients. Second, a pair of scatterplots of spatial cross-correlation is proposed, and the plots can be used to visually reveal the causality behind spatial systems. Based on the global cross-correlation coefficient, Pearson’s correlation coefficient can be decomposed into two parts: direct correlation (partial correlation) and indirect correlation (spatial cross-correlation). As an example, the methodology is applied to the relationships between China’s urbanization and economic development to illustrate how to model spatial cross-correlation phenomena. This study is an introduction to developing the theory of spatial cross-correlation, and future geographical spatial analysis might benefit from these models and indexes. PMID:25993120

Relativistic local quantum field theory for m=0 particles; Campos cuanticos locales relativos a particulas de masa no nula

Energy Technology Data Exchange (ETDEWEB)

Morales Villasevil, A

1965-07-01

A method is introduced ta deal with relativistic quantum field theory for particles with m=0. Two mappings I and J, giving rise respectively to particle and anti particle states, are defined between a test space and the physical Hilbert space. The intrinsic field operator is then defined as the minimal causal linear combinations of operators belonging to the annihilation-creation algebra associated to the germ and antigerm parts of the element. Local elements are introduced as improper test elements and local field operators are constructed in the same way as the intrinsic ones. Commutation rules are given. (Author) 17 refs.

Correlation functions in topological Yang-Mills theory with two fermionic charges

International Nuclear Information System (INIS)

Marculescu, S.

1997-01-01

The solution of the Donaldson cohomology problem for the topological Yang-Mills theory with two fermionic symmetries needs besides the gauge field and its descendants additional fields, hereafter called ascendants of the gauge field. It is shown that the dependence of the ascendants disappears in the all the correlation functions. This property allows one for the usual interpretation of the Donaldson invariants as cocycles of the instanton moduli space. (orig.)

Variational local moment approach: From Kondo effect to Mott transition in correlated electron systems

International Nuclear Information System (INIS)

Kauch, Anna; Byczuk, Krzysztof

2012-01-01

The variational local moment approach (VLMA) solution of the single impurity Anderson model is presented. It generalizes the local moment approach of Logan et al. by invoking the variational principle to determine the lengths of local moments and orbital occupancies. We show that VLMA is a comprehensive, conserving and thermodynamically consistent approximation and treats both Fermi and non-Fermi liquid regimes as well as local moment phases on equal footing. We tested VLMA on selected problems. We solved the single- and multi-orbital impurity Anderson model in various regions of parameters, where different types of Kondo effects occur. The application of VLMA as an impurity solver of the dynamical mean-field theory, used to solve the multi-orbital Hubbard model, is also addressed.

Anomalous Quantum Correlations of Squeezed Light

Science.gov (United States)

Kühn, B.; Vogel, W.; Mraz, M.; Köhnke, S.; Hage, B.

2017-04-01

Three different noise moments of field strength, intensity, and their correlations are simultaneously measured. For this purpose a homodyne cross-correlation measurement [1] is implemented by superimposing the signal field and a weak local oscillator on an unbalanced beam splitter. The relevant information is obtained via the intensity noise correlation of the output modes. Detection details like quantum efficiencies or uncorrelated dark noise are meaningless for our technique. Yet unknown insight in the quantumness of a squeezed signal field is retrieved from the anomalous moment, correlating field strength with intensity noise. A classical inequality including this moment is violated for almost all signal phases. Precognition on quantum theory is superfluous, as our analysis is solely based on classical physics.

Evaluation of macromolecular electron-density map quality using the correlation of local r.m.s. density

International Nuclear Information System (INIS)

Terwilliger, Thomas C.; Berendzen, Joel

1999-01-01

The correlation of local r.m.s. density is shown to be a good measure of the presence of distinct solvent and macromolecule regions in macromolecular electron-density maps. It has recently been shown that the standard deviation of local r.m.s. electron density is a good indicator of the presence of distinct regions of solvent and protein in macromolecular electron-density maps [Terwilliger & Berendzen (1999 ▶). Acta Cryst. D55, 501–505]. Here, it is demonstrated that a complementary measure, the correlation of local r.m.s. density in adjacent regions on the unit cell, is also a good measure of the presence of distinct solvent and protein regions. The correlation of local r.m.s. density is essentially a measure of how contiguous the solvent (and protein) regions are in the electron-density map. This statistic can be calculated in real space or in reciprocal space and has potential uses in evaluation of heavy-atom solutions in the MIR and MAD methods as well as for evaluation of trial phase sets in ab initio phasing procedures

Keldysh meets Lindblad: Correlated Gain and Loss in Higher Order Perturbation Theory

Science.gov (United States)

Stace, Tom; Mueller, Clemens

Motivated by correlated decay processes driving gain, loss and lasing in driven artificial quantum systems, we develop a theoretical technique using Keldysh diagrammatic perturbation theory to derive a Lindblad master equation that goes beyond the usual second order perturbation theory. We demonstrate the method on the driven dissipative Rabi model, including terms up to fourth order in the interaction between the qubit and both the resonator and environment. This results in a large class of Lindblad dissipators and associated rates which go beyond the terms that have previously been proposed to describe similar systems. All of the additional terms contribute to the system behaviour at the same order of perturbation theory. We then apply these results to analyse the phonon-assisted steady-state gain of a microwave field driving a double quantum-dot in a resonator. We show that resonator gain and loss are substantially affected by dephasing- assisted dissipative processes in the quantum-dot system. These additional processes, which go beyond recently proposed polaronic theories, are in good quantitative agreement with experimental observations.

An airloads theory for morphing airfoils in dynamic stall with experimental correlation

Science.gov (United States)

Ahaus, Loren A.

Helicopter rotor blades frequently encounter dynamic stall during normal flight conditions, limiting the applicability of classical thin-airfoil theory at large angles of attack. Also, it is evident that because of the largely different conditions on the advancing and retreating sides of the rotor, future rotorcraft may incorporate dynamically morphing airfoils (trailing-edge aps, dynamic camber, dynamic droop, etc.). Reduced-order aerodynamic models are needed for preliminary design and ight simulation. A unified model for predicting the airloads on a morphing airfoil in dynamic stall is presented, consisting of three components. First, a linear airloads theory allows for arbitrary airfoil deformations consistent with a morphing airfoil. Second, to capture the effects of the wake, the airloads theory is coupled to an induced ow model. Third, the overshoot and time delay associated with dynamic stall are modeled by a second-order dynamic filter, along the lines of the ONERA dynamic stall model. This paper presents a unified airloads model that allows arbitrary airfoil morphing with dynamic stall. Correlations with experimental data validate the theory.

Derivative discontinuity and exchange-correlation potential of meta-GGAs in density-functional theory.

Science.gov (United States)

Eich, F G; Hellgren, Maria

2014-12-14

We investigate fundamental properties of meta-generalized-gradient approximations (meta-GGAs) to the exchange-correlation energy functional, which have an implicit density dependence via the Kohn-Sham kinetic-energy density. To this purpose, we construct the most simple meta-GGA by expressing the local exchange-correlation energy per particle as a function of a fictitious density, which is obtained by inverting the Thomas-Fermi kinetic-energy functional. This simple functional considerably improves the total energy of atoms as compared to the standard local density approximation. The corresponding exchange-correlation potentials are then determined exactly through a solution of the optimized effective potential equation. These potentials support an additional bound state and exhibit a derivative discontinuity at integer particle numbers. We further demonstrate that through the kinetic-energy density any meta-GGA incorporates a derivative discontinuity. However, we also find that for commonly used meta-GGAs the discontinuity is largely underestimated and in some cases even negative.

Derivative discontinuity and exchange-correlation potential of meta-GGAs in density-functional theory

International Nuclear Information System (INIS)

Eich, F. G.; Hellgren, Maria

2014-01-01

We investigate fundamental properties of meta-generalized-gradient approximations (meta-GGAs) to the exchange-correlation energy functional, which have an implicit density dependence via the Kohn-Sham kinetic-energy density. To this purpose, we construct the most simple meta-GGA by expressing the local exchange-correlation energy per particle as a function of a fictitious density, which is obtained by inverting the Thomas-Fermi kinetic-energy functional. This simple functional considerably improves the total energy of atoms as compared to the standard local density approximation. The corresponding exchange-correlation potentials are then determined exactly through a solution of the optimized effective potential equation. These potentials support an additional bound state and exhibit a derivative discontinuity at integer particle numbers. We further demonstrate that through the kinetic-energy density any meta-GGA incorporates a derivative discontinuity. However, we also find that for commonly used meta-GGAs the discontinuity is largely underestimated and in some cases even negative

Structure of a financial cross-correlation matrix under attack

Science.gov (United States)

Lim, Gyuchang; Kim, SooYong; Kim, Junghwan; Kim, Pyungsoo; Kang, Yoonjong; Park, Sanghoon; Park, Inho; Park, Sang-Bum; Kim, Kyungsik

2009-09-01

We investigate the structure of a perturbed stock market in terms of correlation matrices. For the purpose of perturbing a stock market, two distinct methods are used, namely local and global perturbation. The former involves replacing a correlation coefficient of the cross-correlation matrix with one calculated from two Gaussian-distributed time series while the latter reconstructs the cross-correlation matrix just after replacing the original return series with Gaussian-distributed time series. Concerning the local case, it is a technical study only and there is no attempt to model reality. The term ‘global’ means the overall effect of the replacement on other untouched returns. Through statistical analyses such as random matrix theory (RMT), network theory, and the correlation coefficient distributions, we show that the global structure of a stock market is vulnerable to perturbation. However, apart from in the analysis of inverse participation ratios (IPRs), the vulnerability becomes dull under a small-scale perturbation. This means that these analysis tools are inappropriate for monitoring the whole stock market due to the low sensitivity of a stock market to a small-scale perturbation. In contrast, when going down to the structure of business sectors, we confirm that correlation-based business sectors are regrouped in terms of IPRs. This result gives a clue about monitoring the effect of hidden intentions, which are revealed via portfolios taken mostly by large investors.

Shift of the superconducting critical parameters due to correlated disorder

International Nuclear Information System (INIS)

Gitterman, M.; Shapiro, I.; Shapiro, B.Ya.

2012-01-01

Shift of the critical temperature and second critical magnetic field are calculated for a superconductor with Gaussian correlated disorder. All calculations have been performed in the framework of the stochastic Ginzburg-Landau equation. For uncorrelated disorder the macroscopic critical temperature is determined by the average of the local critical temperature across the sample, while for correlated disorder both the critical temperature and the upper critical magnetic field depend on disorder correlation length. In a nonuniform superconductor with randomly distributed local critical temperature both the macroscopic critical temperature and the upper critical magnetic field strongly depend on the characteristic correlation length ρ 0 of correlated disorder. The shift of the macroscopic critical parameters from those for non-correlated disorder, which does not exist for white noise, is obtained for small ρ 0 in the framework of the Ginzburg-Landau theory.

Examining the impact of harmonic correlation on vibrational frequencies calculated in localized coordinates

Energy Technology Data Exchange (ETDEWEB)

Hanson-Heine, Magnus W. D., E-mail: magnus.hansonheine@nottingham.ac.uk [School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom)

2015-10-28

Carefully choosing a set of optimized coordinates for performing vibrational frequency calculations can significantly reduce the anharmonic correlation energy from the self-consistent field treatment of molecular vibrations. However, moving away from normal coordinates also introduces an additional source of correlation energy arising from mode-coupling at the harmonic level. The impact of this new component of the vibrational energy is examined for a range of molecules, and a method is proposed for correcting the resulting self-consistent field frequencies by adding the full coupling energy from connected pairs of harmonic and pseudoharmonic modes, termed vibrational self-consistent field (harmonic correlation). This approach is found to lift the vibrational degeneracies arising from coordinate optimization and provides better agreement with experimental and benchmark frequencies than uncorrected vibrational self-consistent field theory without relying on traditional correlated methods.

Influence of electron correlation and degeneracy on the Fukui matrix and extension of frontier molecular orbital theory to correlated quantum chemical methods.

Science.gov (United States)

Bultinck, Patrick; Van Neck, Dimitri; Acke, Guillaume; Ayers, Paul W

2012-02-21

The Fukui function is considered as the diagonal element of the Fukui matrix in position space, where the Fukui matrix is the derivative of the one particle density matrix (1DM) with respect to the number of electrons. Diagonalization of the Fukui matrix, expressed in an orthogonal orbital basis, explains why regions in space with negative Fukui functions exist. Using a test set of molecules, electron correlation is found to have a remarkable effect on the eigenvalues of the Fukui matrix. The Fukui matrices at the independent electron model level are mathematically proven to always have an eigenvalue equal to exactly unity while the rest of the eigenvalues possibly differ from zero but sum to zero. The loss of idempotency of the 1DM at correlated levels of theory causes the loss of these properties. The influence of electron correlation is examined in detail and the frontier molecular orbital concept is extended to correlated levels of theory by defining it as the eigenvector of the Fukui matrix with the largest eigenvalue. The effect of degeneracy on the Fukui matrix is examined in detail, revealing that this is another way by which the unity eigenvalue and perfect pairing of eigenvalues can disappear.

Reliability measures in item response theory: manifest versus latent correlation functions.

Science.gov (United States)

Milanzi, Elasma; Molenberghs, Geert; Alonso, Ariel; Verbeke, Geert; De Boeck, Paul

2015-02-01

For item response theory (IRT) models, which belong to the class of generalized linear or non-linear mixed models, reliability at the scale of observed scores (i.e., manifest correlation) is more difficult to calculate than latent correlation based reliability, but usually of greater scientific interest. This is not least because it cannot be calculated explicitly when the logit link is used in conjunction with normal random effects. As such, approximations such as Fisher's information coefficient, Cronbach's α, or the latent correlation are calculated, allegedly because it is easy to do so. Cronbach's α has well-known and serious drawbacks, Fisher's information is not meaningful under certain circumstances, and there is an important but often overlooked difference between latent and manifest correlations. Here, manifest correlation refers to correlation between observed scores, while latent correlation refers to correlation between scores at the latent (e.g., logit or probit) scale. Thus, using one in place of the other can lead to erroneous conclusions. Taylor series based reliability measures, which are based on manifest correlation functions, are derived and a careful comparison of reliability measures based on latent correlations, Fisher's information, and exact reliability is carried out. The latent correlations are virtually always considerably higher than their manifest counterparts, Fisher's information measure shows no coherent behaviour (it is even negative in some cases), while the newly introduced Taylor series based approximations reflect the exact reliability very closely. Comparisons among the various types of correlations, for various IRT models, are made using algebraic expressions, Monte Carlo simulations, and data analysis. Given the light computational burden and the performance of Taylor series based reliability measures, their use is recommended. © 2014 The British Psychological Society.

Localized motion in random matrix decomposition of complex financial systems

Science.gov (United States)

Jiang, Xiong-Fei; Zheng, Bo; Ren, Fei; Qiu, Tian

2017-04-01

With the random matrix theory, we decompose the multi-dimensional time series of complex financial systems into a set of orthogonal eigenmode functions, which are classified into the market mode, sector mode, and random mode. In particular, the localized motion generated by the business sectors, plays an important role in financial systems. Both the business sectors and their impact on the stock market are identified from the localized motion. We clarify that the localized motion induces different characteristics of the time correlations for the stock-market index and individual stocks. With a variation of a two-factor model, we reproduce the return-volatility correlations of the eigenmodes.

Reduced density matrix functional theory via a wave function based approach

Energy Technology Data Exchange (ETDEWEB)

Schade, Robert; Bloechl, Peter [Institute for Theoretical Physics, Clausthal University of Technology, Clausthal (Germany); Pruschke, Thomas [Institute for Theoretical Physics, University of Goettingen, Goettingen (Germany)

2016-07-01

We propose a new method for the calculation of the electronic and atomic structure of correlated electron systems based on reduced density matrix functional theory (rDMFT). The density-matrix functional is evaluated on the fly using Levy's constrained search formalism. The present implementation rests on a local approximation of the interaction reminiscent to that of dynamical mean field theory (DMFT). We focus here on additional approximations to the exact density-matrix functional in the local approximation and evaluate their performance.

Experimental evidence for bounds on quantum correlations.

Science.gov (United States)

Bovino, F A; Castagnoli, G; Degiovanni, I P; Castelletto, S

2004-02-13

We implemented the experiment proposed by Cabello in the preceding Letter to test the bounds of quantum correlation. As expected from the theory we found that, for certain choices of local observables, Tsirelson's bound of the Clauser-Horne-Shimony-Holt inequality (2 x square root of 2) is not reached by any quantum states.

Z-1 perturbation theory applied to the correlation energy problem of atoms

International Nuclear Information System (INIS)

Robinson, B.H.

1975-01-01

Rayleigh--Schroedinger Perturbation Theory is applied to obtain directly exact and explicit analytic formulas for the electron correlation energies of N electron systems in terms of their pairwise interactions through second order in Z -1 , where Z is the nucleus of the atom. It is demonstrated that the second order correlation energy may be expressed as exactly the sum of pairwise correlation energies. In the case of no zeroth order degeneracy, the zeroth and first order terms vanish. The expression for the pairwise energies is an infinite sum, all terms of which are of the same sign. There is no numerical differencing. In the case of zeroth order degeneracy it is shown that the above statement concerning the second order energy still holds, but the expressions are a bit more complicated. It is shown that they ''almost'' reduce to a much simpler form. Also, the computation of the first order correlation energy is considered

Quantum Noether identities for non-local transformations in higher-order derivatives theories

International Nuclear Information System (INIS)

Li, Z.P.; Long, Z.W.

2003-01-01

Based on the phase-space generating functional of the Green function for a system with a regular/singular higher-order Lagrangian, the quantum canonical Noether identities (NIs) under a local and non-local transformation in phase space have been deduced, respectively. For a singular higher-order Lagrangian, one must use an effective canonical action I eff P in quantum canonical NIs instead of the classical I P in classical canonical NIs. The quantum NIs under a local and non-local transformation in configuration space for a gauge-invariant system with a higher-order Lagrangian have also been derived. The above results hold true whether or not the Jacobian of the transformation is equal to unity or not. It has been pointed out that in certain cases the quantum NIs may be converted to conservation laws at the quantum level. This algorithm to derive the quantum conservation laws is significantly different from the quantum first Noether theorem. The applications of our formulation to the Yang-Mills fields and non-Abelian Chern-Simons (CS) theories with higher-order derivatives are given, and the conserved quantities at the quantum level for local and non-local transformations are found, respectively. (orig.)

Violation of Bell’s inequality: Must the Einstein locality really be abandoned?

Science.gov (United States)

Jung, Kurt

2017-08-01

Since John Bell has established his famous inequality and several independent experiments have confirmed the distinct polarization correlation of entangled photons predicted by quantum mechanics it is evident that quantum mechanics cannot be explained by local realistic theories. Actually, the observed polarization correlation can be deduced from wave optical considerations. The correlation has its origin in the phase coupling of the two circularly polarized wave packets leaving the photon source simultaneously. The experimental results violate Bell’s inequality although no non-local interactions have to be assumed. In consequence the principle of locality remains valid in the scope of quantum mechanics. However, the principle of realism has to be replaced by the less stringent principle of contextuality.

VEHICLE LOCALIZATION BY LIDAR POINT CORRELATION IMPROVED BY CHANGE DETECTION

Directory of Open Access Journals (Sweden)

A. Schlichting

2016-06-01

Full Text Available LiDAR sensors are proven sensors for accurate vehicle localization. Instead of detecting and matching features in the LiDAR data, we want to use the entire information provided by the scanners. As dynamic objects, like cars, pedestrians or even construction sites could lead to wrong localization results, we use a change detection algorithm to detect these objects in the reference data. If an object occurs in a certain number of measurements at the same position, we mark it and every containing point as static. In the next step, we merge the data of the single measurement epochs to one reference dataset, whereby we only use static points. Further, we also use a classification algorithm to detect trees. For the online localization of the vehicle, we use simulated data of a vertical aligned automotive LiDAR sensor. As we only want to use static objects in this case as well, we use a random forest classifier to detect dynamic scan points online. Since the automotive data is derived from the LiDAR Mobile Mapping System, we are able to use the labelled objects from the reference data generation step to create the training data and further to detect dynamic objects online. The localization then can be done by a point to image correlation method using only static objects. We achieved a localization standard deviation of about 5 cm (position and 0.06° (heading, and were able to successfully localize the vehicle in about 93 % of the cases along a trajectory of 13 km in Hannover, Germany.

Vehicle Localization by LIDAR Point Correlation Improved by Change Detection

Science.gov (United States)

Schlichting, A.; Brenner, C.

2016-06-01

LiDAR sensors are proven sensors for accurate vehicle localization. Instead of detecting and matching features in the LiDAR data, we want to use the entire information provided by the scanners. As dynamic objects, like cars, pedestrians or even construction sites could lead to wrong localization results, we use a change detection algorithm to detect these objects in the reference data. If an object occurs in a certain number of measurements at the same position, we mark it and every containing point as static. In the next step, we merge the data of the single measurement epochs to one reference dataset, whereby we only use static points. Further, we also use a classification algorithm to detect trees. For the online localization of the vehicle, we use simulated data of a vertical aligned automotive LiDAR sensor. As we only want to use static objects in this case as well, we use a random forest classifier to detect dynamic scan points online. Since the automotive data is derived from the LiDAR Mobile Mapping System, we are able to use the labelled objects from the reference data generation step to create the training data and further to detect dynamic objects online. The localization then can be done by a point to image correlation method using only static objects. We achieved a localization standard deviation of about 5 cm (position) and 0.06° (heading), and were able to successfully localize the vehicle in about 93 % of the cases along a trajectory of 13 km in Hannover, Germany.

Non-local boxes and their implementation in Minecraft

Science.gov (United States)

Simnacher, Timo Yannick

PR-boxes are binary devices connecting two remote parties satisfying x AND y = a + b mod 2, where x and y denote the binary inputs and a and b are the respective outcomes without signaling. These devices are named after their inventors Sandu Popescu and Daniel Rohrlich and saturate the Clauser-Horne-Shimony-Holt (CHSH) inequality. This Bell-like inequality bounds the correlation that can exist between two remote, non-signaling, classical systems described by local hidden variable theories. Experiments have now convincingly shown that quantum entanglement cannot be explained by local hidden variable theories. Furthermore, the CHSH inequality provides a method to distinguish quantum systems from super-quantum correlations. The correlation between the outputs of the PR-box goes beyond any quantum entanglement. Though PR-boxes would have impressive consequences, as far as we know they are not physically realizable. However, by introducing PR-boxes to Minecraft as part of the redstone system, which simulates the electrical components for binary computing, we can experience the consequences of super-quantum correlations. For instance, Wim van Dam proved that two parties can use a sufficient number of PR-boxes to compute any Boolean function f(x,y) with only one bit of communication.

Correlation dimension and phase space contraction via extreme value theory

Science.gov (United States)

Faranda, Davide; Vaienti, Sandro

2018-04-01

We show how to obtain theoretical and numerical estimates of correlation dimension and phase space contraction by using the extreme value theory. The maxima of suitable observables sampled along the trajectory of a chaotic dynamical system converge asymptotically to classical extreme value laws where: (i) the inverse of the scale parameter gives the correlation dimension and (ii) the extremal index is associated with the rate of phase space contraction for backward iteration, which in dimension 1 and 2, is closely related to the positive Lyapunov exponent and in higher dimensions is related to the metric entropy. We call it the Dynamical Extremal Index. Numerical estimates are straightforward to obtain as they imply just a simple fit to a univariate distribution. Numerical tests range from low dimensional maps, to generalized Henon maps and climate data. The estimates of the indicators are particularly robust even with relatively short time series.

Localization in f-shell metals

International Nuclear Information System (INIS)

Harrison, W.A.

1984-01-01

Anderson's theory of local moments is applied to the f-shell metals with the use of parameters for the electronic structure given earlier. A criterion for localization (abrupt in this theory) of Z/sub f/ levels per atom is that the resonance width be less than 2U sin 2 (πZ/sub f//14), with U the intra-atomic repulsion associated with s-f transfer. Americium and the heavier actinides satisfy this criterion, as do all the rare earths except cerium; plutonium is borderline. The traditional term ''localized state'' is used here though ''correlated state'' would be more appropriate. For the cases considered the localized states are found to have net spin (or moment) but that is not a necessary condition. They are found to contribute to the f-band pressure on the crystal, but reduced by a factor of about W/sub f//3U, equal to 0.09 for americium, where W/sub f/ is the itinerant f-band width. The localized f levels may themselves be thought to form bands, but with reduced width, and they may even have Fermi surface, though that was not found for the systems considered. A comparison of this state with band ferromagnetism is made. An approximate calculation of the total energy of the localized and delocalized states as a function of volume correctly predicted the large volume and localization for americium

Interferences, ghost images and other quantum correlations according to stochastic optics

International Nuclear Information System (INIS)

Fonseca da Silva, Luciano; Dechoum, Kaled

2012-01-01

There are an extensive variety of experiments in quantum optics that emphasize the non-local character of the coincidence measurements recorded by spatially separated photocounters. These are the cases of ghost image and other interference experiments based on correlated photons produced in, for instance, the process of parametric down-conversion or photon cascades. We propose to analyse some of these correlations in the light of stochastic optics, a local formalism based on classical electrodynamics with added background fluctuations that simulate the vacuum field of quantum electrodynamics, and raise the following question: can these experiments be used to distinguish between quantum entanglement and classical correlations? - Highlights: ► We analyse some quantum correlations in the light of stochastic optics. ► We study how vacuum fluctuations can rule quantum correlations. ► Many criteria cannot be considered a boundary between quantum and classical theories. ► Non-locality is a misused term in relation to many observed experiments.

Current Issues in Finite-T Density-Functional Theory and Warm-Correlated Matter †

Directory of Open Access Journals (Sweden)

M. W. C. Dharma-wardana

2016-03-01

Full Text Available Finite-temperature density functional theory (DFT has become of topical interest, partly due to the increasing ability to create novel states of warm-correlated matter (WCM.Warm-dense matter (WDM, ultra-fast matter (UFM, and high-energy density matter (HEDM may all be regarded as subclasses of WCM. Strong electron-electron, ion-ion and electron-ion correlation effects and partial degeneracies are found in these systems where the electron temperature Te is comparable to the electron Fermi energy EF. Thus, many electrons are in continuum states which are partially occupied. The ion subsystem may be solid, liquid or plasma, with many states of ionization with ionic charge Zj. Quasi-equilibria with the ion temperature Ti ≠ Te are common. The ion subsystem in WCM can no longer be treated as a passive “external potential”, as is customary in T = 0 DFT dominated by solid-state theory or quantum chemistry. Many basic questions arise in trying to implement DFT for WCM. Hohenberg-Kohn-Mermin theory can be adapted for treating these systems if suitable finite-T exchange-correlation (XC functionals can be constructed. They are functionals of both the one-body electron density ne and the one-body ion densities ρj. Here, j counts many species of nuclei or charge states. A method of approximately but accurately mapping the quantum electrons to a classical Coulomb gas enables one to treat electron-ion systems entirely classically at any temperature and arbitrary spin polarization, using exchange-correlation effects calculated in situ, directly from the pair-distribution functions. This eliminates the need for any XC-functionals. This classical map has been used to calculate the equation of state of WDM systems, and construct a finite-T XC functional that is found to be in close agreement with recent quantum path-integral simulation data. In this review, current developments and concerns in finite-T DFT, especially in the context of non-relativistic warm

Renormalization group improved computation of correlation functions in theories with nontrivial phase diagram

DEFF Research Database (Denmark)

Codello, Alessandro; Tonero, Alberto

2016-01-01

We present a simple and consistent way to compute correlation functions in interacting theories with nontrivial phase diagram. As an example we show how to consistently compute the four-point function in three dimensional Z2-scalar theories. The idea is to perform the path integral by weighting...... the momentum modes that contribute to it according to their renormalization group (RG) relevance, i.e. we weight each mode according to the value of the running couplings at that scale. In this way, we are able to encode in a loop computation the information regarding the RG trajectory along which we...

Multicultural adolescents between tradition and postmodernity: Dialogical Self Theory and the paradox of localization and globalization.

Science.gov (United States)

van Meijl, Toon

2012-01-01

This chapter builds on Dialogical Self Theory to investigate the identity development of adolescents growing up in multicultural societies. Their cultural identity is not only compounded by the rapid cultural changes associated with globalization, but also by the paradoxical revival of cultural traditions which the large-scale compression of time and space has incited at local levels of society. Dialogical Self Theory, which is based on the metaphor of the self as a "society of mind," helps to understand the dilemmas of tradition and postmodernity, of localization and globalization, within the self of individual youngsters. Copyright © 2012 Wiley Periodicals, Inc., A Wiley Company.

China’s Institutional Architecture: A New Institutional Economics and Organization Theory Perspective on the Links between Local Governance and Local Enterprises

NARCIS (Netherlands)

B. Krug (Barbara); H. Hendrischke (Hans)

2008-01-01

textabstractWe start our exploration of China’s institutional change by asking what the China experience can tell us about institutional economics and organization theory. We point to under-researched areas such as the formation of firms and the interplay between firms and local politics. Our

arXiv Algebraic Cycles and Local Anomalies in F-Theory

CERN Document Server

Bies, Martin; Weigand, Timo

2017-11-16

We introduce a set of identities in the cohomology ring of elliptic fibrations which are equivalent to the cancellation of gauge and mixed gauge-gravitational anomalies in F-theory compactifications to four and six dimensions. The identities consist in (co)homological relations between complex codimension-two cycles. The same set of relations, once evaluated on elliptic Calabi-Yau three-folds and four-folds, is shown to universally govern the structure of anomalies and their Green-Schwarz cancellation in six- and four-dimensional F-theory vacua, respectively. We furthermore conjecture that these relations hold not only within the cohomology ring, but even at the level of the Chow ring, i.e. as relations among codimension-two cycles modulo rational equivalence. We verify this conjecture in non-trivial examples with Abelian and non-Abelian gauge groups factors. Apart from governing the structure of local anomalies, the identities in the Chow ring relate different types of gauge backgrounds on elliptically fibre...

Exact density functional and wave function embedding schemes based on orbital localization

International Nuclear Information System (INIS)

Hégely, Bence; Nagy, Péter R.; Kállay, Mihály; Ferenczy, György G.

2016-01-01

Exact schemes for the embedding of density functional theory (DFT) and wave function theory (WFT) methods into lower-level DFT or WFT approaches are introduced utilizing orbital localization. First, a simple modification of the projector-based embedding scheme of Manby and co-workers [J. Chem. Phys. 140, 18A507 (2014)] is proposed. We also use localized orbitals to partition the system, but instead of augmenting the Fock operator with a somewhat arbitrary level-shift projector we solve the Huzinaga-equation, which strictly enforces the Pauli exclusion principle. Second, the embedding of WFT methods in local correlation approaches is studied. Since the latter methods split up the system into local domains, very simple embedding theories can be defined if the domains of the active subsystem and the environment are treated at a different level. The considered embedding schemes are benchmarked for reaction energies and compared to quantum mechanics (QM)/molecular mechanics (MM) and vacuum embedding. We conclude that for DFT-in-DFT embedding, the Huzinaga-equation-based scheme is more efficient than the other approaches, but QM/MM or even simple vacuum embedding is still competitive in particular cases. Concerning the embedding of wave function methods, the clear winner is the embedding of WFT into low-level local correlation approaches, and WFT-in-DFT embedding can only be more advantageous if a non-hybrid density functional is employed.

Exact density functional and wave function embedding schemes based on orbital localization

Science.gov (United States)

Hégely, Bence; Nagy, Péter R.; Ferenczy, György G.; Kállay, Mihály

2016-08-01

Exact schemes for the embedding of density functional theory (DFT) and wave function theory (WFT) methods into lower-level DFT or WFT approaches are introduced utilizing orbital localization. First, a simple modification of the projector-based embedding scheme of Manby and co-workers [J. Chem. Phys. 140, 18A507 (2014)] is proposed. We also use localized orbitals to partition the system, but instead of augmenting the Fock operator with a somewhat arbitrary level-shift projector we solve the Huzinaga-equation, which strictly enforces the Pauli exclusion principle. Second, the embedding of WFT methods in local correlation approaches is studied. Since the latter methods split up the system into local domains, very simple embedding theories can be defined if the domains of the active subsystem and the environment are treated at a different level. The considered embedding schemes are benchmarked for reaction energies and compared to quantum mechanics (QM)/molecular mechanics (MM) and vacuum embedding. We conclude that for DFT-in-DFT embedding, the Huzinaga-equation-based scheme is more efficient than the other approaches, but QM/MM or even simple vacuum embedding is still competitive in particular cases. Concerning the embedding of wave function methods, the clear winner is the embedding of WFT into low-level local correlation approaches, and WFT-in-DFT embedding can only be more advantageous if a non-hybrid density functional is employed.

Exact density functional and wave function embedding schemes based on orbital localization

Energy Technology Data Exchange (ETDEWEB)

Hégely, Bence; Nagy, Péter R.; Kállay, Mihály, E-mail: kallay@mail.bme.hu [MTA-BME Lendület Quantum Chemistry Research Group, Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, P.O. Box 91, H-1521 Budapest (Hungary); Ferenczy, György G. [Medicinal Chemistry Research Group, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, H-1117 Budapest (Hungary); Department of Biophysics and Radiation Biology, Semmelweis University, Tűzoltó u. 37-47, H-1094 Budapest (Hungary)

2016-08-14

Exact schemes for the embedding of density functional theory (DFT) and wave function theory (WFT) methods into lower-level DFT or WFT approaches are introduced utilizing orbital localization. First, a simple modification of the projector-based embedding scheme of Manby and co-workers [J. Chem. Phys. 140, 18A507 (2014)] is proposed. We also use localized orbitals to partition the system, but instead of augmenting the Fock operator with a somewhat arbitrary level-shift projector we solve the Huzinaga-equation, which strictly enforces the Pauli exclusion principle. Second, the embedding of WFT methods in local correlation approaches is studied. Since the latter methods split up the system into local domains, very simple embedding theories can be defined if the domains of the active subsystem and the environment are treated at a different level. The considered embedding schemes are benchmarked for reaction energies and compared to quantum mechanics (QM)/molecular mechanics (MM) and vacuum embedding. We conclude that for DFT-in-DFT embedding, the Huzinaga-equation-based scheme is more efficient than the other approaches, but QM/MM or even simple vacuum embedding is still competitive in particular cases. Concerning the embedding of wave function methods, the clear winner is the embedding of WFT into low-level local correlation approaches, and WFT-in-DFT embedding can only be more advantageous if a non-hybrid density functional is employed.

Local probe studies on lattice distortions and electronic correlations in manganites

CERN Document Server

lopes, Armandina; Correia, João Guilherme

This thesis presents an experimental study on lattice distortions and electronic correlations in colossal magnetoresistive magnetic oxides. The Perturbed Angular Correlation local probe technique is used to study selected manganite systems in order to obtain relevant insight into microscopic phenomena responsible for their macroscopic pr operties. Complementary structural, magnetic and electric characterization was performed. The work is focused on the following aspects: \\\\Lattice distortions and polaron clusters in LaMnO$_{3+ \\Delta}$ system. A study of the electric field gradi ent and magnetic hyperfine field was performed in representative samples of the LaMnO$_{3+ \\Delta}$ system, and correlated with macroscopic information obtained in the same samples. Particular attention was given to the LaMnO$_{3.12}$ sample since this compound is a prototype of a ferromagnetic-insulat or manganite, presenting a rhombohedric- orthorhombic structural phase transition near room temperature. We found that random distribu...

Logarithmic two-point correlation functions from a z=2 Lifshitz model

International Nuclear Information System (INIS)

Zingg, T.

2014-01-01

The Einstein-Proca action is known to have asymptotically locally Lifshitz spacetimes as classical solutions. For dynamical exponent z=2, two-point correlation functions for fluctuations around such a geometry are derived analytically. It is found that the retarded correlators are stable in the sense that all quasinormal modes are situated in the lower half-plane of complex frequencies. Correlators in the longitudinal channel exhibit features that are reminiscent of a structure usually obtained in field theories that are logarithmic, i.e. contain an indecomposable but non-diagonalizable highest weight representation. This provides further evidence for conjecturing the model at hand as a candidate for a gravity dual of a logarithmic field theory with anisotropic scaling symmetry

Performance of exchange-correlation functionals in density functional theory calculations for liquid metal: A benchmark test for sodium

Science.gov (United States)

Han, Jeong-Hwan; Oda, Takuji

2018-04-01

The performance of exchange-correlation functionals in density-functional theory (DFT) calculations for liquid metal has not been sufficiently examined. In the present study, benchmark tests of Perdew-Burke-Ernzerhof (PBE), Armiento-Mattsson 2005 (AM05), PBE re-parameterized for solids, and local density approximation (LDA) functionals are conducted for liquid sodium. The pair correlation function, equilibrium atomic volume, bulk modulus, and relative enthalpy are evaluated at 600 K and 1000 K. Compared with the available experimental data, the errors range from -11.2% to 0.0% for the atomic volume, from -5.2% to 22.0% for the bulk modulus, and from -3.5% to 2.5% for the relative enthalpy depending on the DFT functional. The generalized gradient approximation functionals are superior to the LDA functional, and the PBE and AM05 functionals exhibit the best performance. In addition, we assess whether the error tendency in liquid simulations is comparable to that in solid simulations, which would suggest that the atomic volume and relative enthalpy performances are comparable between solid and liquid states but that the bulk modulus performance is not. These benchmark test results indicate that the results of liquid simulations are significantly dependent on the exchange-correlation functional and that the DFT functional performance in solid simulations can be used to roughly estimate the performance in liquid simulations.

Relativistic quantum theory of composite systems

International Nuclear Information System (INIS)

Sogami, I.

1978-01-01

A relativistic quantum theory free from the difficulties of tachyons and ghosts is formulated to describe the scattering processes between composite systems of spinless quarks. To evade the complication brewed by introducing gluon fields or strings, valence quarks are effectively assumed to be in the relative motion of harmonic oscillation correlating with the motion of the composite system as a whole. A quark-antiquark system is represented by a bilocal field describing a sequence of mesons and every meson is identified with the composite system in a definite eigenstate of relative motion. The quantization is performed in the interaction picture, so that the microcausal condition is satisfied by local fields which result from the decomposition of bilocal fields. Imposing a weakened macrocausal condition on the whole motion of the extended system, a causal bilocal propagator is defined and a consistent time ordering among bilocal fields is defined. The invariant S-matrix is obtained and the graphical method for the calculation of its elements is developed in parallel with the conventional local field theory. For the (bilocal field) 3 interaction any malignant divergence does not appear excepting those in the renormalizable local field theory. The theory provides one promising and comprehensive phenomenology of hadrons which is suitable especially to describe the hard structure of hadrons. (author)

Supergravity, Non-Conformal Field Theories and Brane-Worlds

CERN Document Server

Gherghetta, Tony; Gherghetta, Tony; Oz, Yaron

2002-01-01

We consider the supergravity dual descriptions of non-conformal super Yang-Mills theories realized on the world-volume of Dp-branes. We use the dual description to compute stress-energy tensor and current correlators. We apply the results to the study of dilatonic brane-worlds described by non-conformal field theories coupled to gravity. We find that brane-worlds based on D4 and D5 branes exhibit a localization of gauge and gravitational fields. We calculate the corrections to the Newton and Coulomb laws in these theories.

D-branes in N=2 Liouville theory and its mirror

International Nuclear Information System (INIS)

Israel, Dan; Pakman, Ari; Troost, Jan

2005-01-01

We study D-branes in the mirror pair N=2 Liouville/supersymmetric SL(2,R)/U(1) coset superconformal field theories. We build D0-, D1- and D2-branes, on the basis of the boundary state construction for the H 3 + conformal field theory. We also construct D0-branes in an orbifold that rotates the angular direction of the cigar. We show how the poles of correlators associated to localized states and bulk interactions naturally decouple in the one-point functions of localized and extended branes. We stress the role played in the analysis of D-brane spectra by primaries in SL(2,R)/U(1) which are descendents of the parent theory

Quasispin model of itinerant magnetism: High-temperature theory

International Nuclear Information System (INIS)

Liu, S.H.

1977-01-01

The high-temperature properties of itinerant magnetic systems are examined by using the coherent-potential approximation. We assume a local moment on each atom so that at elevated temperatures there is a number of reversed spins. The coherent potential is solved, and from that the moment on each atom is determined self-consistently. It is found that when the condition for ferromagnetic ordering is satisfied, the local moments persist even above the critical temperature. Conversely, if local moments do not exist at high temperatures, the system can at most condense into a spin-density-wave state. Furthermore, spin-flip scatterings of the conduction electrons from the local moments give rise to additional correlation not treated in the coherent-potential approximation. This correlation energy is an important part of the coupling energy of the local moments. The relations between our work and the theories of Friedel, Hubbard, and others are discussed

Correlation functions with fusion-channel multiplicity in W{sub 3} Toda field theory

Energy Technology Data Exchange (ETDEWEB)

Belavin, Vladimir [I.E. Tamm Department of Theoretical Physics, P.N. Lebedev Physical Institute,Leninsky Avenue 53, 119991 Moscow (Russian Federation); Department of Quantum Physics, Institute for Information Transmission Problems,Bolshoy Karetny per. 19, 127994 Moscow (Russian Federation); Estienne, Benoit [LPTHE, CNRS and Université Pierre et Marie Curie,Sorbonne Universités, 4 Place Jussieu, 75252 Paris Cedex 05 (France); Foda, Omar [School of Mathematics and Statistics, University of Melbourne,Parkville, Victoria 3010 (Australia); Santachiara, Raoul [LPTMS, CNRS (UMR 8626), Université Paris-Saclay,15 rue Georges Clémenceau, 91405 Orsay (France)

2016-06-22

Current studies of W{sub N} Toda field theory focus on correlation functions such that the W{sub N} highest-weight representations in the fusion channels are multiplicity-free. In this work, we study W{sub 3} Toda 4-point functions with multiplicity in the fusion channel. The conformal blocks of these 4-point functions involve matrix elements of a fully-degenerate primary field with a highest-weight in the adjoint representation of sl{sub 3}, and a fully-degenerate primary field with a highest-weight in the fundamental representation of sl{sub 3}. We show that, when the fusion rules do not involve multiplicities, the matrix elements of the fully-degenerate adjoint field, between two arbitrary descendant states, can be computed explicitly, on equal footing with the matrix elements of the semi-degenerate fundamental field. Using null-state conditions, we obtain a fourth-order Fuchsian differential equation for the conformal blocks. Using Okubo theory, we show that, due to the presence of multiplicities, this differential equation belongs to a class of Fuchsian equations that is different from those that have appeared so far in W{sub N} theories. We solve this equation, compute its monodromy group, and construct the monodromy-invariant correlation functions. This computation shows in detail how the ambiguities that are caused by the presence of multiplicities are fixed by requiring monodromy-invariance.

Social cognitive theory correlates of moderate-intensity exercise among adults with type 2 diabetes.

Science.gov (United States)

Heiss, Valerie J; Petosa, R L

2016-01-01

The purpose of this study was to identify social cognitive theory (SCT) correlates of moderate- to vigorous-intensity exercise (MVPA) among adults with type 2 diabetes. Adults with type 2 diabetes (N = 181) participated in the study. Participants were recruited through ResearchMatch.org to complete an online survey. The survey used previously validated instruments to measure dimensions of self-efficacy, self-regulation, social support, outcome expectations, the physical environment, and minutes of MVPA per week. Spearman Rank Correlations were used to determine the relationship between SCT variables and MVPA. Classification and Regression Analysis using a decision tree model was used to determine the amount of variance in MVPA explained by SCT variables. Due to low levels of vigorous activity, only moderate-intensity exercise (MIE) was analyzed. SCT variables explained 42.4% of the variance in MIE. Self-monitoring, social support from family, social support from friends, and self-evaluative outcome expectations all contributed to the variability in MIE. Other contributing variables included self-reward, task self-efficacy, social outcome expectations, overcoming barriers, and self-efficacy for making time for exercise. SCT is a useful theory for identifying correlates of MIE among adults with type 2 diabetes. The SCT correlates can be used to refine diabetes education programs to target the adoption and maintenance of regular exercise.

Effective field theories for correlated electrons

International Nuclear Information System (INIS)

Wallington, J.P.

1999-10-01

In this thesis, techniques of functional integration are applied to the construction of effective field theories for models of strongly correlated electrons. This is accomplished by means of the Hubbard-Stratonovic transformation which maps a system of interacting fermions onto one of free fermions interacting, not with each other, but with bosonic fields representing the collective modes of the system. Different choices of transformation are investigated throughout the thesis. It is shown that there exists a new group of discrete symmetries and transformations of the Hubbard model. Using this new group, the problem of choosing a Hubbard-Stratonovic decomposition of the Hubbard interaction term is solved. In the context of the exotic doped barium bismuthates, an extended Hubbard model with on-site attraction and nearest neighbour repulsion is studied. Mean field and renormalisation group analyses show a 'pseudospin-flop' from charge density wave to superconductivity as a function of filling. The nearest neighbour attractive Hubbard model on a quasi-2D lattice is studied as a simple phenomenological model for the high-T c cuprates. Mean field theory shows a transition from pure d-wave to pure s-wave superconductivity, via a mixed symmetry s + id state. Using Gaussian fluctuations, the BCS-Bose crossover is examined and suggestions are made about the origin of the angle dependence of the pseudogap. The continuum delta-shell potential model is introduced for anisotropic superconductors. Its mean field phases are studied and found to have some unusual properties. The BCS-Bose crossover is examined and the results are compared with those of the lattice model. Quasi-2D (highly anisotropic 3D) systems are considered. The critical properties of a Bose gas are investigated as the degree of anisotropy is varied. A new 2D Bose condensate state is found. A renormalisation group analysis is used to investigate the crossover from 2D to 3D. (author)

Local Correlation during Ostwald ripening of two-dimensional islands on Ag(111)

NARCIS (Netherlands)

Morgenstern, Karina; Rosenfeld, G.; Comsa, George

1999-01-01

Using two-dimensional Ag adatom islands on Ag(111) as a model system, we study the importance of local correlations in diffusion-limited Ostwald ripening. For the coverages studied (0.08, 0.21, and 0.3 ML), we find that the ripening can be surprisingly well described in a nearest neighbour model

Correlation Matrix Renormalization Theory: Improving Accuracy with Two-Electron Density-Matrix Sum Rules.

Science.gov (United States)

Liu, C; Liu, J; Yao, Y X; Wu, P; Wang, C Z; Ho, K M

2016-10-11

We recently proposed the correlation matrix renormalization (CMR) theory to treat the electronic correlation effects [Phys. Rev. B 2014, 89, 045131 and Sci. Rep. 2015, 5, 13478] in ground state total energy calculations of molecular systems using the Gutzwiller variational wave function (GWF). By adopting a number of approximations, the computational effort of the CMR can be reduced to a level similar to Hartree-Fock calculations. This paper reports our recent progress in minimizing the error originating from some of these approximations. We introduce a novel sum-rule correction to obtain a more accurate description of the intersite electron correlation effects in total energy calculations. Benchmark calculations are performed on a set of molecules to show the reasonable accuracy of the method.

Operator theory of angular momentum nad orientational auto-correlation functions

International Nuclear Information System (INIS)

Evans, M.W.

1982-01-01

The rigorous relation between the orientational auto-correlation function and the angular momentum autocorrelation function is described in two cases of interest. First when description of the complete zero THz- spectrum is required from the Mori continued fraction expansion for the angular momentum autocorrelation function and second when rotation/translation effects are important. The Mori-Evans theory of 1976, relying on the simple Shimizu relation is found to be essentially unaffected by the higher order corrections recently worked out by Ford and co-workers in the Markov limit. The mutual interaction of rotation and translation is important in determining the details of both the orientational and angular momentum auto-correlation function's (a.c.f.'s) in the presence of sample anisotropy or a symmetry breaking field. In this case it is essential to regard the angular momentum a.c.f. as non-Markovian and methods are developed to relate this to the orientational a.c.f. in the presence of rotation/translation coupling. (author)

Comparison of Subset-Based Local and Finite Element-Based Global Digital Image Correlation

KAUST Repository

Pan, Bing; Wang, B.; Lubineau, Gilles; Moussawi, Ali

2015-01-01

Digital image correlation (DIC) techniques require an image matching algorithm to register the same physical points represented in different images. Subset-based local DIC and finite element-based (FE-based) global DIC are the two primary image matching methods that have been extensively investigated and regularly used in the field of experimental mechanics. Due to its straightforward implementation and high efficiency, subset-based local DIC has been used in almost all commercial DIC packages. However, it is argued by some researchers that FE-based global DIC offers better accuracy because of the enforced continuity between element nodes. We propose a detailed performance comparison between these different DIC algorithms both in terms of measurement accuracy and computational efficiency. Then, by measuring displacements of the same calculation points using the same calculation algorithms (e.g., correlation criterion, initial guess estimation, subpixel interpolation, optimization algorithm and convergence conditions) and identical calculation parameters (e.g., subset or element size), the performances of subset-based local DIC and two FE-based global DIC approaches are carefully compared in terms of measurement error and computational efficiency using both numerical tests and real experiments. A detailed examination of the experimental results reveals that, when subset (element) size is not very small and the local deformation within a subset (element) can be well approximated by the shape function used, standard subset-based local DIC approach not only provides better results in measured displacements, but also demonstrates much higher computation efficiency. However, several special merits of FE-based global DIC approaches are indicated.

Comparison of Subset-Based Local and Finite Element-Based Global Digital Image Correlation

KAUST Repository

Pan, Bing

2015-02-12

Digital image correlation (DIC) techniques require an image matching algorithm to register the same physical points represented in different images. Subset-based local DIC and finite element-based (FE-based) global DIC are the two primary image matching methods that have been extensively investigated and regularly used in the field of experimental mechanics. Due to its straightforward implementation and high efficiency, subset-based local DIC has been used in almost all commercial DIC packages. However, it is argued by some researchers that FE-based global DIC offers better accuracy because of the enforced continuity between element nodes. We propose a detailed performance comparison between these different DIC algorithms both in terms of measurement accuracy and computational efficiency. Then, by measuring displacements of the same calculation points using the same calculation algorithms (e.g., correlation criterion, initial guess estimation, subpixel interpolation, optimization algorithm and convergence conditions) and identical calculation parameters (e.g., subset or element size), the performances of subset-based local DIC and two FE-based global DIC approaches are carefully compared in terms of measurement error and computational efficiency using both numerical tests and real experiments. A detailed examination of the experimental results reveals that, when subset (element) size is not very small and the local deformation within a subset (element) can be well approximated by the shape function used, standard subset-based local DIC approach not only provides better results in measured displacements, but also demonstrates much higher computation efficiency. However, several special merits of FE-based global DIC approaches are indicated.

Explicitly-correlated ring-coupled-cluster-doubles theory: Including exchange for computations on closed-shell systems

Energy Technology Data Exchange (ETDEWEB)

Hehn, Anna-Sophia; Holzer, Christof; Klopper, Wim, E-mail: klopper@kit.edu

2016-11-10

Highlights: • Ring-coupled-cluster-doubles approach now implemented with exchange terms. • Ring-coupled-cluster-doubles approach now implemented with F12 functions. • Szabo–Ostlund scheme (SO2) implemented for use in SAPT. • Fast convergence to the limit of a complete basis. • Implementation in the TURBOMOLE program system. - Abstract: Random-phase-approximation (RPA) methods have proven to be powerful tools in electronic-structure theory, being non-empirical, computationally efficient and broadly applicable to a variety of molecular systems including small-gap systems, transition-metal compounds and dispersion-dominated complexes. Applications are however hindered due to the slow basis-set convergence of the electron-correlation energy with the one-electron basis. As a remedy, we present approximate explicitly-correlated RPA approaches based on the ring-coupled-cluster-doubles formulation including exchange contributions. Test calculations demonstrate that the basis-set convergence of correlation energies is drastically accelerated through the explicitly-correlated approach, reaching 99% of the basis-set limit with triple-zeta basis sets. When implemented in close analogy to early work by Szabo and Ostlund [36], the new explicitly-correlated ring-coupled-cluster-doubles approach including exchange has the perspective to become a valuable tool in the framework of symmetry-adapted perturbation theory (SAPT) for the computation of dispersion energies of molecular complexes of weakly interacting closed-shell systems.

Local realistic theories and quantum mechanics for the two-neutral-kaon system

International Nuclear Information System (INIS)

Dalitz, R.H.; Garbarino, G.

2001-01-01

The predictions of local realistic theories for the observables concerning the evolution of a K 0 K-bar 0 quantum entangled pair (created in the decay of the phi-meson) are discussed. It is shown, in agreement with Bell's theorem, that the most general local hidden-variable model fails in reproducing the whole set of quantum-mechanical joint probabilities. We achieve these conclusion by employing two different approaches. In the first approach, the local realistic observables are deduced from the most general premises concerning locality and realism, and Bell-like inequalities are not employed. The other approach makes use of Bell's inequalities. In the first approach, under particular conditions for the detection times, the discrepancy between quantum mechanics and local realism for the time-dependent asymmetry turns out to be not less than 20%. A similar incompatibility can be made evident by means of a Bell-type test by employing both Wigner's and (once properly normalized probabilities are used) Clauser-Horne-Shimony-Holt's inequalities. Because of its relatively low experimental accuracy, the data obtained by the CPLEAR collaboration for the asymmetry parameter do not yet allow a decisive test of local realism. Such a test, both with and without the use of Bell's inequalities, should be feasible in the future at the Frascati PHI-factory

Recent developments in LIBXC - A comprehensive library of functionals for density functional theory

Science.gov (United States)

Lehtola, Susi; Steigemann, Conrad; Oliveira, Micael J. T.; Marques, Miguel A. L.

2018-01-01

LIBXC is a library of exchange-correlation functionals for density-functional theory. We are concerned with semi-local functionals (or the semi-local part of hybrid functionals), namely local-density approximations, generalized-gradient approximations, and meta-generalized-gradient approximations. Currently we include around 400 functionals for the exchange, correlation, and the kinetic energy, spanning more than 50 years of research. Moreover, LIBXC is by now used by more than 20 codes, not only from the atomic, molecular, and solid-state physics, but also from the quantum chemistry communities.

Dynamical self-arrest in symmetric and asymmetric diblock copolymer melts using a replica approach within a local theory.

Science.gov (United States)

Wu, Sangwook

2009-03-01

We investigate dynamical self-arrest in a diblock copolymer melt using a replica approach within a self-consistent local method based on dynamical mean-field theory (DMFT). The local replica approach effectively predicts (chiN)_{A} for dynamical self-arrest in a block copolymer melt for symmetric and asymmetric cases. We discuss the competition of the cubic and quartic interactions in the Landau free energy for a block copolymer melt in stabilizing a glassy state depending on the chain length. Our local replica theory provides a universal value for the dynamical self-arrest in block copolymer melts with (chiN)_{A} approximately 10.5+64N;{-3/10} for the symmetric case.

Mathematical correlation of modal-parameter-identification methods via system-realization theory

Science.gov (United States)

Juang, Jer-Nan

1987-01-01

A unified approach is introduced using system-realization theory to derive and correlate modal-parameter-identification methods for flexible structures. Several different time-domain methods are analyzed and treated. A basic mathematical foundation is presented which provides insight into the field of modal-parameter identification for comparison and evaluation. The relation among various existing methods is established and discussed. This report serves as a starting point to stimulate additional research toward the unification of the many possible approaches for modal-parameter identification.

A note on local GUT models in F-theory

International Nuclear Information System (INIS)

Chen, C.-M.; Chung, Y.-C.

2010-01-01

We construct non-minimal GUT local models in the F-theory configuration. The gauge group on the bulk G S is one rank higher than the GUT gauge group. The line bundles on the curves are nontrivial to break G S down to the GUT gauge groups. We demonstrate examples of SU(5) GUT from G S =SU(6) and G S =SO(10), the flipped SU(5) from G S =SO(10), and the SO(10) GUT from G S =SO(12) and G S =E 6 . We obtain complete GUT matter spectra and couplings, with minimum exotic matter contents. GUT gauge group breaking to MSSM is achievable by instanton configurations.

General Theory versus ENA Theory: Comparing Their Predictive Accuracy and Scope.

Science.gov (United States)

Ellis, Lee; Hoskin, Anthony; Hartley, Richard; Walsh, Anthony; Widmayer, Alan; Ratnasingam, Malini

2015-12-01

General theory attributes criminal behavior primarily to low self-control, whereas evolutionary neuroandrogenic (ENA) theory envisions criminality as being a crude form of status-striving promoted by high brain exposure to androgens. General theory predicts that self-control will be negatively correlated with risk-taking, while ENA theory implies that these two variables should actually be positively correlated. According to ENA theory, traits such as pain tolerance and muscularity will be positively associated with risk-taking and criminality while general theory makes no predictions concerning these relationships. Data from Malaysia and the United States are used to test 10 hypotheses derived from one or both of these theories. As predicted by both theories, risk-taking was positively correlated with criminality in both countries. However, contrary to general theory and consistent with ENA theory, the correlation between self-control and risk-taking was positive in both countries. General theory's prediction of an inverse correlation between low self-control and criminality was largely supported by the U.S. data but only weakly supported by the Malaysian data. ENA theory's predictions of positive correlations between pain tolerance, muscularity, and offending were largely confirmed. For the 10 hypotheses tested, ENA theory surpassed general theory in predictive scope and accuracy. © The Author(s) 2014.

Highly-correlated charges in polyelectrolyte gels

Science.gov (United States)

Sing, Charles; Zwanikken, Johannes; Olvera de La Cruz, Monica

2013-03-01

Polyelectrolyte gels are ubiquitous in polymer physics due to their attractive combination of structural and chemical features that permit the realization of ``environmentally responsive'' systems. The conventional conceptual picture of the volume response of these systems is based on a competition between osmotic and elastic effects. We elaborate on this fundamental understanding by including ion correlations through the use of liquid-state integral equation theory. This allows for a statistical mechanical representation of the state of the system that not only surpasses traditional Poisson-Boltzmann theories but also renders structural features in a highly accurate fashion. In particular, the local ion structure is elucidated, allowing for detailed articulation of charge inversion and condensation effects in the context of gel swelling. The inclusion of correlations has a number of ramifications that become apparent, with enhanced gel collapse and excluded volume competitions that give rise to novel and ion-dependent reentrant swelling effects. We expect this rigorous theory to prove instructive in understanding any number of gelated structures, such as chromosomes or designed synthetic materials for drug delivery.

Investigation of the local component of power-reactor noise via diffusion theory

International Nuclear Information System (INIS)

Kosaly, G.

1975-03-01

The aim of the paper is to provide a theoretical background for the phenomenological model, which postulates the existence of a local component in the neutron noise of a light water cooled boiling water reactor. After the introductory review of the phenomenological model, noise calculation are performed by help of the one-group and two-group diffusion theory. Only in the two-group diffusion model it is succeeded to find a term in the response to a propagating disturbance of density which results in a small volume of neutrons physical sensivity around the point of observation. The problem, whether this local component can be a dominating term in the solution or not, is investigated in the Appenix. (Sz.Z.)

Measurement of Local Deformations in Steel Monostrands Using Digital Image Correlation

DEFF Research Database (Denmark)

Winkler, Jan; Fischer, Gregor; Georgakis, Christos T.

2014-01-01

The local deformation mechanisms in steel monostrands have a significant influence on their fatigue life and failure mode. However, the observation and quantification of deformations in monostrands experiencing axial and transverse deformations is challenging because of their complex geometry......, difficulties with the placement of strain gauges in the vicinity of the anchorage, and, most importantly, the relatively small magnitude of deformation occurring in the monostrand. This paper focuses on the measurement of localized deformations in high-strength steel monostrands using the digital image...... correlation (DIC) technique. The presented technique enables the measurement of individual wire strains along the length of the monostrand and also provides quantitative information on the relative movement between individual wires, leading to a more in-depth understanding of the underlying fatigue mechanisms...

Boson spectra and correlations for thermal locally equilibrium systems

International Nuclear Information System (INIS)

Sinyukov, Y.M.

1999-01-01

The single- and multi-particle inclusive spectra for strongly inhomogeneous thermal boson systems are studied using the method of statistical operator. The thermal Wick's theorem is generalized and the analytical solution of the problem for a boost-invariant expanding boson gas is found. The results demonstrate the effects of inhomogeneity for such a system: the spectra and correlations for particles with wavelengths larger than the system's homogeneity lengths change essentially as compared with the results based on the local Bose-Einstein thermal distributions. The effects noticeably grow for overpopulated media, where the chemical potential associated with violation of chemical equilibrium is large enough. (author)

Correlation Dimension Estimates of Global and Local Temperature Data.

Science.gov (United States)

Wang, Qiang

1995-11-01

The author has attempted to detect the presence of low-dimensional deterministic chaos in temperature data by estimating the correlation dimension with the Hill estimate that has been recently developed by Mikosch and Wang. There is no convincing evidence of low dimensionality with either global dataset (Southern Hemisphere monthly average temperatures from 1858 to 1984) or local temperature dataset (daily minimums at Auckland, New Zealand). Any apparent reduction in the dimension estimates appears to be due large1y, if not entirely, to effects of statistical bias, but neither is it a purely random stochastic process. The dimension of the climatic attractor may be significantly larger than 10.

Nonlocal gauge theories

International Nuclear Information System (INIS)

Partovi, M.H.

1982-01-01

From a generalization of the covariant derivative, nonlocal gauge theories are developed. These theories enjoy local gauge invariance and associated Ward identities, a corresponding locally conserved current, and a locally conserved energy-momentum tensor, with the Ward identities implying the masslessness of the gauge field as in local theories. Their ultraviolet behavior allows the presence as well as the absence of the Adler-Bell-Jackiw anomaly, the latter in analogy with lattice theories

Global hybrids from the semiclassical atom theory satisfying the local density linear response.

Science.gov (United States)

Fabiano, Eduardo; Constantin, Lucian A; Cortona, Pietro; Della Sala, Fabio

2015-01-13

We propose global hybrid approximations of the exchange-correlation (XC) energy functional which reproduce well the modified fourth-order gradient expansion of the exchange energy in the semiclassical limit of many-electron neutral atoms and recover the full local density approximation (LDA) linear response. These XC functionals represent the hybrid versions of the APBE functional [Phys. Rev. Lett. 2011, 106, 186406] yet employing an additional correlation functional which uses the localization concept of the correlation energy density to improve the compatibility with the Hartree-Fock exchange as well as the coupling-constant-resolved XC potential energy. Broad energetic and structural testing, including thermochemistry and geometry, transition metal complexes, noncovalent interactions, gold clusters and small gold-molecule interfaces, as well as an analysis of the hybrid parameters, show that our construction is quite robust. In particular, our testing shows that the resulting hybrid, including 20% of Hartree-Fock exchange and named hAPBE, performs remarkably well for a broad palette of systems and properties, being generally better than popular hybrids (PBE0 and B3LYP). Semiempirical dispersion corrections are also provided.

Near-Edge X-ray Absorption Fine Structure within Multilevel Coupled Cluster Theory.

Science.gov (United States)

Myhre, Rolf H; Coriani, Sonia; Koch, Henrik

2016-06-14

Core excited states are challenging to calculate, mainly because they are embedded in a manifold of high-energy valence-excited states. However, their locality makes their determination ideal for local correlation methods. In this paper, we demonstrate the performance of multilevel coupled cluster theory in computing core spectra both within the core-valence separated and the asymmetric Lanczos implementations of coupled cluster linear response theory. We also propose a visualization tool to analyze the excitations using the difference between the ground-state and excited-state electron densities.

Foundations of complex analysis in non locally convex spaces function theory without convexity condition

CERN Document Server

Bayoumi, A

2003-01-01

All the existing books in Infinite Dimensional Complex Analysis focus on the problems of locally convex spaces. However, the theory without convexity condition is covered for the first time in this book. This shows that we are really working with a new, important and interesting field. Theory of functions and nonlinear analysis problems are widespread in the mathematical modeling of real world systems in a very broad range of applications. During the past three decades many new results from the author have helped to solve multiextreme problems arising from important situations, non-convex and

Characterization of the spatial structure of local functional connectivity using multi-distance average correlation measures.

Science.gov (United States)

Macia, Didac; Pujol, Jesus; Blanco-Hinojo, Laura; Martínez-Vilavella, Gerard; Martín-Santos, Rocío; Deus, Joan

2018-04-24

There is ample evidence from basic research in neuroscience of the importance of local cortico-cortical networks. Millimetric resolution is achievable with current functional MRI (fMRI) scanners and sequences, and consequently a number of "local" activity similarity measures have been defined to describe patterns of segregation and integration at this spatial scale. We have introduced the use of Iso-Distant local Average Correlation (IDAC), easily defined as the average fMRI temporal correlation of a given voxel with other voxels placed at increasingly separated iso-distant intervals, to characterize the curve of local fMRI signal similarities. IDAC curves can be statistically compared using parametric multivariate statistics. Furthermore, by using RGB color-coding to display jointly IDAC values belonging to three different distance lags, IDAC curves can also be displayed as multi-distance IDAC maps. We applied IDAC analysis to a sample of 41 subjects scanned under two different conditions, a resting state and an auditory-visual continuous stimulation. Multi-distance IDAC mapping was able to discriminate between gross anatomo-functional cortical areas and, moreover, was sensitive to modulation between the two brain conditions in areas known to activate and de-activate during audio-visual tasks. Unlike previous fMRI local similarity measures already in use, our approach draws special attention to the continuous smooth pattern of local functional connectivity.

Mathematical correlation of modal parameter identification methods via system realization theory

Science.gov (United States)

Juang, J. N.

1986-01-01

A unified approach is introduced using system realization theory to derive and correlate modal parameter identification methods for flexible structures. Several different time-domain and frequency-domain methods are analyzed and treated. A basic mathematical foundation is presented which provides insight into the field of modal parameter identification for comparison and evaluation. The relation among various existing methods is established and discussed. This report serves as a starting point to stimulate additional research towards the unification of the many possible approaches for modal parameter identification.

Multiple-scattering formalism for correlated systems: A KKR-DMFT approach

International Nuclear Information System (INIS)

Minar, J.; Perlov, A.; Ebert, H.; Chioncel, L.; Katsnelson, M. I.; Lichtenstein, A.I.

2005-01-01

We present a charge and self-energy self-consistent computational scheme for correlated systems based on the Korringa-Kohn-Rostoker (KKR) multiple scattering theory with the many-body effects described by the means of dynamical mean field theory (DMFT). The corresponding local multiorbital and energy dependent self-energy is included into the set of radial differential equations for the single-site wave functions. The KKR Green's function is written in terms of the multiple scattering path operator, the later one being evaluated using the single-site solution for the t-matrix that in turn is determined by the wave functions. An appealing feature of this approach is that it allows to consider local quantum and disorder fluctuations on the same footing. Within the coherent potential approximation (CPA) the correlated atoms are placed into a combined effective medium determined by the DMFT self-consistency condition. Results of corresponding calculations for pure Fe, Ni, and Fe x Ni 1-x alloys are presented

Correlations of zero-entropy critical states in the XXZ model: integrability and Luttinger theory far from the ground state

Directory of Open Access Journals (Sweden)

R. Vlijm, I. S. Eliëns, J. -S. Caux

2016-10-01

Full Text Available Pumping a finite energy density into a quantum system typically leads to `melted' states characterized by exponentially-decaying correlations, as is the case for finite-temperature equilibrium situations. An important exception to this rule are states which, while being at high energy, maintain a low entropy. Such states can interestingly still display features of quantum criticality, especially in one dimension. Here, we consider high-energy states in anisotropic Heisenberg quantum spin chains obtained by splitting the ground state's magnon Fermi sea into separate pieces. Using methods based on integrability, we provide a detailed study of static and dynamical spin-spin correlations. These carry distinctive signatures of the Fermi sea splittings, which would be observable in eventual experimental realizations. Going further, we employ a multi-component Tomonaga-Luttinger model in order to predict the asymptotics of static correlations. For this effective field theory, we fix all universal exponents from energetics, and all non-universal correlation prefactors using finite-size scaling of matrix elements. The correlations obtained directly from integrability and those emerging from the Luttinger field theory description are shown to be in extremely good correspondence, as expected, for the large distance asymptotics, but surprisingly also for the short distance behavior. Finally, we discuss the description of dynamical correlations from a mobile impurity model, and clarify the relation of the effective field theory parameters to the Bethe Ansatz solution.

SU-F-R-20: Image Texture Features Correlate with Time to Local Failure in Lung SBRT Patients

Energy Technology Data Exchange (ETDEWEB)

Andrews, M; Abazeed, M; Woody, N; Stephans, K; Videtic, G; Xia, P; Zhuang, T [The Cleveland Clinic Foundation, Cleveland, OH (United States)

2016-06-15

Purpose: To explore possible correlation between CT image-based texture and histogram features and time-to-local-failure in early stage non-small cell lung cancer (NSCLC) patients treated with stereotactic body radiotherapy (SBRT).Methods and Materials: From an IRB-approved lung SBRT registry for patients treated between 2009–2013 we selected 48 (20 male, 28 female) patients with local failure. Median patient age was 72.3±10.3 years. Mean time to local failure was 15 ± 7.1 months. Physician-contoured gross tumor volumes (GTV) on the planning CT images were processed and 3D gray-level co-occurrence matrix (GLCM) based texture and histogram features were calculated in Matlab. Data were exported to R and a multiple linear regression model was used to examine the relationship between texture features and time-to-local-failure. Results: Multiple linear regression revealed that entropy (p=0.0233, multiple R2=0.60) from GLCM-based texture analysis and the standard deviation (p=0.0194, multiple R2=0.60) from the histogram-based features were statistically significantly correlated with the time-to-local-failure. Conclusion: Image-based texture analysis can be used to predict certain aspects of treatment outcomes of NSCLC patients treated with SBRT. We found entropy and standard deviation calculated for the GTV on the CT images displayed a statistically significant correlation with and time-to-local-failure in lung SBRT patients.

SU-F-R-20: Image Texture Features Correlate with Time to Local Failure in Lung SBRT Patients

International Nuclear Information System (INIS)

Andrews, M; Abazeed, M; Woody, N; Stephans, K; Videtic, G; Xia, P; Zhuang, T

2016-01-01

Purpose: To explore possible correlation between CT image-based texture and histogram features and time-to-local-failure in early stage non-small cell lung cancer (NSCLC) patients treated with stereotactic body radiotherapy (SBRT).Methods and Materials: From an IRB-approved lung SBRT registry for patients treated between 2009–2013 we selected 48 (20 male, 28 female) patients with local failure. Median patient age was 72.3±10.3 years. Mean time to local failure was 15 ± 7.1 months. Physician-contoured gross tumor volumes (GTV) on the planning CT images were processed and 3D gray-level co-occurrence matrix (GLCM) based texture and histogram features were calculated in Matlab. Data were exported to R and a multiple linear regression model was used to examine the relationship between texture features and time-to-local-failure. Results: Multiple linear regression revealed that entropy (p=0.0233, multiple R2=0.60) from GLCM-based texture analysis and the standard deviation (p=0.0194, multiple R2=0.60) from the histogram-based features were statistically significantly correlated with the time-to-local-failure. Conclusion: Image-based texture analysis can be used to predict certain aspects of treatment outcomes of NSCLC patients treated with SBRT. We found entropy and standard deviation calculated for the GTV on the CT images displayed a statistically significant correlation with and time-to-local-failure in lung SBRT patients.

Increasing the applicability of density functional theory. IV. Consequences of ionization-potential improved exchange-correlation potentials.

Science.gov (United States)

Verma, Prakash; Bartlett, Rodney J

2014-05-14

This paper's objective is to create a "consistent" mean-field based Kohn-Sham (KS) density functional theory (DFT) meaning the functional should not only provide good total energy properties, but also the corresponding KS eigenvalues should be accurate approximations to the vertical ionization potentials (VIPs) of the molecule, as the latter condition attests to the viability of the exchange-correlation potential (VXC). None of the prominently used DFT approaches show these properties: the optimized effective potential VXC based ab initio dft does. A local, range-separated hybrid potential cam-QTP-00 is introduced as the basis for a "consistent" KS DFT approach. The computed VIPs as the negative of KS eigenvalue have a mean absolute error of 0.8 eV for an extensive set of molecule's electron ionizations, including the core. Barrier heights, equilibrium geometries, and magnetic properties obtained from the potential are in good agreement with experiment. A similar accuracy with less computational efforts can be achieved by using a non-variational global hybrid variant of the QTP-00 approach.

Plasma heating by relativistic electron beams: correlations between experiment and theory

International Nuclear Information System (INIS)

Thode, L.E.; Godfrey, B.B.

1975-01-01

The streaming instability is the primary heating mechanism in most, if not all, experiments in which the beam is injected into partially or fully ionized gas. In plasma heating experiments, the relativistic beam must traverse an anode foil before interacting with the plasma. The linear theory for such a scattered beam is discussed, including a criterion for the onset of the kinetic interaction. A nonlinear model of the two-stream instability for a scattered beam is developed. Using this model, data from ten experiments are unfolded to obtain the following correlations: (i) for a fixed anode foil, the dependence of the plasma heating on the beam-to-plasma density ratio is due to anode foil scattering, (ii) for a fixed beam-to-plasma density ratio, the predicted change in the magnitude of plasma heating as a function of the anode foil is in agreement with experiment, and (iii) the plasma heating tentatively appears to be proportional to the beam kinetic energy density and beam pulse length. For a fixed anode foil, theory also predicts that the energy deposition is improved by increasing the beam electron energy γmc 2 . Presently, no experiment has been performed to confirm this aspect of the theory

Using the electron localization function to correct for confinement physics in semi-local density functional theory

International Nuclear Information System (INIS)

Hao, Feng; Mattsson, Ann E.; Armiento, Rickard

2014-01-01

We have previously proposed that further improved functionals for density functional theory can be constructed based on the Armiento-Mattsson subsystem functional scheme if, in addition to the uniform electron gas and surface models used in the Armiento-Mattsson 2005 functional, a model for the strongly confined electron gas is also added. However, of central importance for this scheme is an index that identifies regions in space where the correction provided by the confined electron gas should be applied. The electron localization function (ELF) is a well-known indicator of strongly localized electrons. We use a model of a confined electron gas based on the harmonic oscillator to show that regions with high ELF directly coincide with regions where common exchange energy functionals have large errors. This suggests that the harmonic oscillator model together with an index based on the ELF provides the crucial ingredients for future improved semi-local functionals. For a practical illustration of how the proposed scheme is intended to work for a physical system we discuss monoclinic cupric oxide, CuO. A thorough discussion of this system leads us to promote the cell geometry of CuO as a useful benchmark for future semi-local functionals. Very high ELF values are found in a shell around the O ions, and take its maximum value along the Cu–O directions. An estimate of the exchange functional error from the effect of electron confinement in these regions suggests a magnitude and sign that could account for the error in cell geometry

Connections on the state-space over conformal field theories

International Nuclear Information System (INIS)

Ranganathan, K.; Sonoda, H.; Zwiebach, B.

1994-01-01

Motivated by the problem of background independence of closed string field theory we study geometry on the infinite vector bundle of local fields over the space of conformal field theories (CFTs). With any connection we can associate an excluded domain D for the integral of marginal operators, and an operator one-form ω μ . The pair (D, ω μ ) determines the covariant derivative of any correlator of local fields. We obtain interesting classes of connections in which ω μ 's can be written in terms of CFT data. For these connections we compute their curvatures in terms of four-point correlators, D, and ω μ . Among these connections three are of particular interest. A flat, metric compatible connection Γ, and connections c and c with non-vanishing curvature, with the latter metric compatible. The flat connection cannot be used to do parallel transport over a finite distance. Parallel transport with either c or c, however, allows us to construct a CFT in the state-space of another CFT a finite distance away. The construction is given in the form of perturbation theory manifestly free of divergences. (orig.)

Long-time tails of the heat-conductivity time correlation functions for a magnetized plasma - a kinetic theory approach

NARCIS (Netherlands)

Schoolderman, A.J.; Suttorp, L.G.

1989-01-01

The long-time behaviour of the longitudinal and the transverse heat conductivity time correlation functions for a magnetized one-component plasma is studied by means of kinetic theory. To that end these correlation functions, which are defined as the inverse Laplace transforms of the dynamic heat

Non-local correlations via Wigner-Yanase skew information in two SC-qubit having mutual interaction under phase decoherence

Science.gov (United States)

Mohamed, Abdel-Baset A.

2017-10-01

An analytical solution of the master equation that describes a superconducting cavity containing two coupled superconducting charge qubits is obtained. Quantum-mechanical correlations based on Wigner-Yanase skew information, as local quantum uncertainty and uncertainty-induced quantum non-locality, are compared to the concurrence under the effects of the phase decoherence. Local quantum uncertainty exhibits sudden changes during its time evolution and revival process. Sudden death and sudden birth occur only for entanglement, depending on the initial state of the two coupled charge qubits, while the correlations of skew information does not vanish. The quantum correlations of skew information are found to be sensitive to the dephasing rate, the photons number in the cavity, the interaction strength between the two qubits, and the qubit distribution angle of the initial state. With a proper initial state, the stationary correlation of the skew information has a non-zero stationary value for a long time interval under the phase decoherence, that it may be useful in quantum information and computation processes.

Analysis of correlation structure in Lymantria dispar L. larvae from locally adapted populations

Directory of Open Access Journals (Sweden)

Mrdaković Marija

2013-01-01

Full Text Available The influence of allelochemical stress and population origin on the patterns of phenotypic and genetic correlations among life history traits and digestive enzyme activities were investigated in larvae of the gypsy moth (Lymantria dispar L.; Lepidoptera: Lymantriidae. Thirty-two full-sib families from oak (suitable host plant, Quercus population, and twenty-six full-sib families from locust-tree (unsuitable host plant, Robinia population forests were reared on an artificial diet, with or without a 5% tannic acid supplement. Comparison of correlation matrices revealed significant similarity between the two populations in the structure of phenotypic and genetic correlations of life history traits and of digestive enzyme activities. The patterns of correlations of the examined traits, within each of the two locally adapted populations and in the presence of allelochemical stress, remained stabile despite the different selection pressures that mold these traits. [Projekat Ministarstva nauke Republike Srbije, br. 173027

Analytical energy gradients for explicitly correlated wave functions. I. Explicitly correlated second-order Møller-Plesset perturbation theory

Science.gov (United States)

Győrffy, Werner; Knizia, Gerald; Werner, Hans-Joachim

2017-12-01

We present the theory and algorithms for computing analytical energy gradients for explicitly correlated second-order Møller-Plesset perturbation theory (MP2-F12). The main difficulty in F12 gradient theory arises from the large number of two-electron integrals for which effective two-body density matrices and integral derivatives need to be calculated. For efficiency, the density fitting approximation is used for evaluating all two-electron integrals and their derivatives. The accuracies of various previously proposed MP2-F12 approximations [3C, 3C(HY1), 3*C(HY1), and 3*A] are demonstrated by computing equilibrium geometries for a set of molecules containing first- and second-row elements, using double-ζ to quintuple-ζ basis sets. Generally, the convergence of the bond lengths and angles with respect to the basis set size is strongly improved by the F12 treatment, and augmented triple-ζ basis sets are sufficient to closely approach the basis set limit. The results obtained with the different approximations differ only very slightly. This paper is the first step towards analytical gradients for coupled-cluster singles and doubles with perturbative treatment of triple excitations, which will be presented in the second part of this series.

Correlated Keldysh-Faisal-Reiss theory of above-threshold double ionization of He in intense laser fields

International Nuclear Information System (INIS)

Becker, A.; Faisal, F.H.M.

1994-01-01

We have developed a correlated Keldysh-Faisal-Reiss theory of laser-induced double ionization of a two-electron atom. The basic N-photon T matrix and the expression for N-photon triple-differential rates or cross sections (TDCS's) are derived. The theory is applied to investigate the TDCS's for very-high-order multiphoton double ionization of He with lasers of wavelength λ=248 nm and λ=617 nm. Comparison with the uncorrelated results reveals a dramatic influence of the final-state e-e correlation on the above-threshold TDCS's to be measured in coincidence experiments in intense laser fields. The limiting case of the TDCS's for weak-field double ionization of He by a synchrotron photon is also investigated; the results confirm the earlier theoretical findings and recent experimental results in that case

Extended BPH renormalization of cutoff scalar field theories

International Nuclear Information System (INIS)

Chalmers, G.

1996-01-01

We show through the use of diagrammatic techniques and a newly adapted BPH renormalization method that general momentum cutoff scalar field theories in four dimensions are perturbatively renormalizable. Weinberg close-quote s convergence theorem is used to show that operators in the Lagrangian with dimension greater than four, which are divided by powers of the cutoff, produce perturbatively only local divergences in the two-, three-, and four-point correlation functions. The naive use of the convergence theorem together with the BPH method is not appropriate for understanding the local divergences and renormalizability of these theories. We also show that the renormalized Green close-quote s functions are the same as in ordinary Φ 4 theory up to corrections suppressed by inverse powers of the cutoff. These conclusions are consistent with those of existing proofs based on the renormalization group. copyright 1996 The American Physical Society

Correlation functions of the energy-momentum tensor in SU(2) gauge theory at finite temperature

DEFF Research Database (Denmark)

Huebner, K.; Karsch, F.; Pica, Claudio

2008-01-01

We calculate correlation functions of the energy-momentum tensor in the vicinity of the deconfinement phase transition of (3+1)-dimensional SU(2) gauge theory and discuss their critical behavior in the vicinity of the second order deconfinement transition. We show that correlation functions...... of the trace of the energy momentum tensor diverge uniformly at the critical point in proportion to the specific heat singularity. Correlation functions of the pressure, on the other hand, stay finite at the critical point. We discuss the consequences of these findings for the analysis of transport...... coefficients, in particular the bulk viscosity, in the vicinity of a second order phase transition point....

Correlation effects in superconducting quantum dot systems