Ghost field realizations of the spinor W2,s strings based on the linear W1,2,s algebras
International Nuclear Information System (INIS)
Liu Yuxiao; Ren Jirong; Zhang Lijie
2005-01-01
It has been shown that certain W algebras can be linearized by the inclusion of a spin-1 current. This provides a way of obtaining new realizations of the W algebras. In this paper, we investigate the new ghost field realizations of the W 2,s (s=3,4) algebras, making use of the fact that these two algebras can be linearized. We then construct the nilpotent BRST charges of the spinor non-critical W 2,s strings with these new realizations. (author)
New spinor fields classes and applications
da Rocha, Roldao
2017-01-01
After revisiting the well-known Lounesto classification of spinor fields, wherefrom the bilinear covariants are considered as the landmark beyond Wigner classification, relevant features of regular and singular spinor fields are presented. Hence, non-standard spinor fields are scrutinised, together with their associated dynamics, paving recently found applications in Physics. The case of the new classes of spinors on 7-manifolds is revisited to provide concrete examples.
New spinor fields on Lorentzian 7-manifolds
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Bonora, L. [International School for Advanced Studies (SISSA),Via Bonomea 265, 34136 Trieste (Italy); Rocha, Roldão da [Centro de Matemática, Computação e Cognição, Universidade Federal do ABC,Avenida dos Estados, 5001, Santo André (Brazil)
2016-01-21
This paper deals with the classification of spinor fields according to the bilinear covariants in 7 dimensions. The previously investigated Riemannian case is characterized by either one spinor field class, in the real case of Majorana spinors, or three non-trivial classes in the most general complex case. In this paper we show that by imposing appropriate conditions on spinor fields in 7d manifolds with Lorentzian metric, the formerly obtained obstructions for new classes of spinor fields can be circumvented. New spinor fields classes are then explicitly constructed. In particular, on 7-manifolds with asymptotically flat black hole background, these spinors can define a generalized current density which further defines a time Killing vector at the spatial infinity.
Quantum wormhole with spinor field
International Nuclear Information System (INIS)
Wang Wenfu; Tao Caide
1994-01-01
Using the Hawking-Page boundary condition, we discuss the quantum wormhole with spinor field. The corresponding Wheeler-De Witt equation is derived, and the wave function of the wormhole calculated. After analysing the wormhole's wave function, the authors found that the probability density of the wormhole appearing at a = 0 is zero, and the minimal radius of the wormhole is on the Planck scale
Algebraic and Dirac-Hestenes spinors and spinor fields
International Nuclear Information System (INIS)
Rodrigues, Waldyr A. Jr.
2004-01-01
Almost all presentations of Dirac theory in first or second quantization in physics (and mathematics) textbooks make use of covariant Dirac spinor fields. An exception is the presentation of that theory (first quantization) offered originally by Hestenes and now used by many authors. There, a new concept of spinor field (as a sum of nonhomogeneous even multivectors fields) is used. However, a careful analysis (detailed below) shows that the original Hestenes definition cannot be correct since it conflicts with the meaning of the Fierz identities. In this paper we start a program dedicated to the examination of the mathematical and physical basis for a comprehensive definition of the objects used by Hestenes. In order to do that we give a preliminary definition of algebraic spinor fields (ASF) and Dirac-Hestenes spinor fields (DHSF) on Minkowski space-time as some equivalence classes of pairs (Ξ u ,ψ Ξ u ), where Ξ u is a spinorial frame field and ψ Ξ u is an appropriate sum of multivectors fields (to be specified below). The necessity of our definitions are shown by a careful analysis of possible formulations of Dirac theory and the meaning of the set of Fierz identities associated with the bilinear covariants (on Minkowski space-time) made with ASF or DHSF. We believe that the present paper clarifies some misunderstandings (past and recent) appearing on the literature of the subject. It will be followed by a sequel paper where definitive definitions of ASF and DHSF are given as appropriate sections of a vector bundle called the left spin-Clifford bundle. The bundle formulation is essential in order to be possible to produce a coherent theory for the covariant derivatives of these fields on arbitrary Riemann-Cartan space-times. The present paper contains also Appendixes A-E which exhibits a truly useful collection of results concerning the theory of Clifford algebras (including many tricks of the trade) necessary for the intelligibility of the text
Bilinear covariants and spinor fields duality in quantum Clifford algebras
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Abłamowicz, Rafał, E-mail: rablamowicz@tntech.edu [Department of Mathematics, Box 5054, Tennessee Technological University, Cookeville, Tennessee 38505 (United States); Gonçalves, Icaro, E-mail: icaro.goncalves@ufabc.edu.br [Instituto de Matemática e Estatística, Universidade de São Paulo, Rua do Matão, 1010, 05508-090, São Paulo, SP (Brazil); Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, 09210-170 Santo André, SP (Brazil); Rocha, Roldão da, E-mail: roldao.rocha@ufabc.edu.br [Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, 09210-170 Santo André, SP (Brazil); International School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste (Italy)
2014-10-15
Classification of quantum spinor fields according to quantum bilinear covariants is introduced in a context of quantum Clifford algebras on Minkowski spacetime. Once the bilinear covariants are expressed in terms of algebraic spinor fields, the duality between spinor and quantum spinor fields can be discussed. Thus, by endowing the underlying spacetime with an arbitrary bilinear form with an antisymmetric part in addition to a symmetric spacetime metric, quantum algebraic spinor fields and deformed bilinear covariants can be constructed. They are thus compared to the classical (non quantum) ones. Classes of quantum spinor fields classes are introduced and compared with Lounesto's spinor field classification. A physical interpretation of the deformed parts and the underlying Z-grading is proposed. The existence of an arbitrary bilinear form endowing the spacetime already has been explored in the literature in the context of quantum gravity [S. W. Hawking, “The unpredictability of quantum gravity,” Commun. Math. Phys. 87, 395 (1982)]. Here, it is shown further to play a prominent role in the structure of Dirac, Weyl, and Majorana spinor fields, besides the most general flagpoles and flag-dipoles. We introduce a new duality between the standard and the quantum spinor fields, by showing that when Clifford algebras over vector spaces endowed with an arbitrary bilinear form are taken into account, a mixture among the classes does occur. Consequently, novel features regarding the spinor fields can be derived.
Spinor Field Nonlinearity and Space-Time Geometry
Saha, Bijan
2018-03-01
Within the scope of Bianchi type VI,VI0,V, III, I, LRSBI and FRW cosmological models we have studied the role of nonlinear spinor field on the evolution of the Universe and the spinor field itself. It was found that due to the presence of non-trivial non-diagonal components of the energy-momentum tensor of the spinor field in the anisotropic space-time, there occur some severe restrictions both on the metric functions and on the components of the spinor field. In this report we have considered a polynomial nonlinearity which is a function of invariants constructed from the bilinear spinor forms. It is found that in case of a Bianchi type-VI space-time, depending of the sign of self-coupling constants, the model allows either late time acceleration or oscillatory mode of evolution. In case of a Bianchi VI 0 type space-time due to the specific behavior of the spinor field we have two different scenarios. In one case the invariants constructed from bilinear spinor forms become trivial, thus giving rise to a massless and linear spinor field Lagrangian. This case is equivalent to the vacuum solution of the Bianchi VI 0 type space-time. The second case allows non-vanishing massive and nonlinear terms and depending on the sign of coupling constants gives rise to accelerating mode of expansion or the one that after obtaining some maximum value contracts and ends in big crunch, consequently generating space-time singularity. In case of a Bianchi type-V model there occur two possibilities. In one case we found that the metric functions are similar to each other. In this case the Universe expands with acceleration if the self-coupling constant is taken to be a positive one, whereas a negative coupling constant gives rise to a cyclic or periodic solution. In the second case the spinor mass and the spinor field nonlinearity vanish and the Universe expands linearly in time. In case of a Bianchi type-III model the space-time remains locally rotationally symmetric all the time
Explicit field realizations of W algebras
International Nuclear Information System (INIS)
Wei Shaowen; Liu Yuxiao; Ren Jirong; Zhang Lijie
2009-01-01
The fact that certain nonlinear W 2,s algebras can be linearized by the inclusion of a spin-1 current can provide a simple way to realize W 2,s algebras from linear W 1,2,s algebras. In this paper, we first construct the explicit field realizations of linear W 1,2,s algebras with double scalar and double spinor, respectively. Then, after a change of basis, the realizations of W 2,s algebras are presented. The results show that all these realizations are Romans-type realizations.
Spinor description of the curvatures of D = 5 gauge fields
Uvarov, D. V.
2017-03-01
Spinor description of the curvatures of D = 5 Yang-Mills, Rarita-Schwinger and gravitational fields is considered. Restrictions imposed on the curvature spinors by the dynamical equations and Bianchi identities are studied. In the absence of sources symmetric curvature spinors with 2 s indices obey first-order equations that in the linearized limit reduce to Dirac-type equations for massless free fields. These equations allow for a higher-spin generalization similarly to 4 d case. Their solution in the form of the integral over Lorentz-harmonic variables parametrizing coset manifold SO(1, 4)/( SO(1,1) × ISO(3)) isomorphic to the three-sphere is considered.
Spinors fields in co-dimension one braneworlds
Mendes, W. M.; Alencar, G.; Landim, R. R.
2018-02-01
In this work we analyze the zero mode localization and resonances of 1/2-spin fermions in co-dimension one Randall-Sundrum braneworld scenarios. We consider delta-like, domain walls and deformed domain walls membranes. Beyond the influence of the spacetime dimension D we also consider three types of couplings: (i) the standard Yukawa coupling with the scalar field and parameter η 1, (ii) a Yukawa-dilaton coupling with two parameters η 2 and λ and (iii) a dilaton derivative coupling with parameter h. Together with the deformation parameter s, we end up with five free parameter to be considered. For the zero mode we find that the localization is dependent of D, because the spinorial representation changes when the bulk dimensionality is odd or even and must be treated separately. For case (i) we find that in odd dimensions only one chirality can be localized and for even dimension a massless Dirac spinor is trapped over the brane. In the cases (ii) and (iii) we find that for some values of the parameters, both chiralities can be localized in odd dimensions and for even dimensions we obtain that the massless Dirac spinor is trapped over the brane. We also calculated numerically resonances for cases (ii) and (iii) by using the transfer matrix method. We find that, for deformed defects, the increasing of D induces a shift in the peaks of resonances. For a given λ with domain walls, we find that the resonances can show up by changing the spacetime dimensionality. For example, the same case in D = 5 do not induces resonances but when we consider D = 10 one peak of resonance is found. Therefore the introduction of more dimensions, diversely from the bosonic case, can change drastically the zero mode and resonances in fermion fields.
Quantum theory of spinor field in four-dimensional Riemannian space-time
International Nuclear Information System (INIS)
Shavokhina, N.S.
1996-01-01
The review deals with the spinor field in the four-dimensional Riemannian space-time. The field beys the Dirac-Fock-Ivanenko equation. Principles of quantization of the spinor field in the Riemannian space-time are formulated which in a particular case of the plane space-time are equivalent to the canonical rules of quantization. The formulated principles are exemplified by the De Sitter space-time. The study of quantum field theory in the De Sitter space-time is interesting because it itself leads to a method of an invariant well for plane space-time. However, the study of the quantum spinor field theory in an arbitrary Riemannian space-time allows one to take into account the influence of the external gravitational field on the quantized spinor field. 60 refs
Non-minimal fields of the pure spinor string in general curved backgrounds
Energy Technology Data Exchange (ETDEWEB)
Chandia, Osvaldo [Departamento de Ciencias, Facultad de Artes Liberales, Universidad Adolfo Ibáñez,Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez,Diagonal Las Torres 2640, Peñalolén, Santiago (Chile); Vallilo, Brenno Carlini [Departamento de Ciencias Físicas, Facultad de Ciencias Exactas, Universidad Andrés Bello,República 220, Santiago (Chile)
2015-02-16
We study the coupling of the non-minimal ghost fields of the pure spinor superstring in general curved backgrounds. The coupling is found solving the consistency relations from the nilpotency of the non-minimal BRST charge.
Nonlinear Spinor Field in Non-Diagonal Bianchi Type Space-Time
Directory of Open Access Journals (Sweden)
Saha Bijan
2018-01-01
Full Text Available Within the scope of the non-diagonal Bianchi cosmological models we have studied the role of the spinor field in the evolution of the Universe. In the non-diagonal Bianchi models the spinor field distribution along the main axis is anisotropic and does not vanish in the absence of the spinor field nonlinearity. Hence within these models perfect fluid, dark energy etc. cannot be simulated by the spinor field nonlinearity. The equation for volume scale V in the case of non-diagonal Bianchi models contains a term with first derivative of V explicitly and does not allow exact solution by quadratures. Like the diagonal models the non-diagonal Bianchi space-time becomes locally rotationally symmetric even in the presence of a spinor field. It was found that depending on the sign of the coupling constant the model allows either an open Universe that rapidly grows up or a close Universe that ends in a Big Crunch singularity.
One-particle reducible contribution to the one-loop spinor propagator in a constant field
Directory of Open Access Journals (Sweden)
N. Ahmadiniaz
2017-11-01
Full Text Available Extending work by Gies and Karbstein on the Euler–Heisenberg Lagrangian, it has recently been shown that the one-loop propagator of a charged scalar particle in a constant electromagnetic field has a one-particle reducible contribution in addition to the well-studied irreducible one. Here we further generalize this result to the spinor case, and find the same relation between the reducible term, the tree-level propagator and the one-loop Euler–Heisenberg Lagrangian as in the scalar case. Our demonstration uses a novel worldline path integral representation of the photon-dressed spinor propagator in a constant electromagnetic field background.
One-particle reducible contribution to the one-loop spinor propagator in a constant field
Ahmadiniaz, N.; Bastianelli, F.; Corradini, O.; Edwards, J. P.; Schubert, C.
2017-11-01
Extending work by Gies and Karbstein on the Euler-Heisenberg Lagrangian, it has recently been shown that the one-loop propagator of a charged scalar particle in a constant electromagnetic field has a one-particle reducible contribution in addition to the well-studied irreducible one. Here we further generalize this result to the spinor case, and find the same relation between the reducible term, the tree-level propagator and the one-loop Euler-Heisenberg Lagrangian as in the scalar case. Our demonstration uses a novel worldline path integral representation of the photon-dressed spinor propagator in a constant electromagnetic field background.
Pure spinors as auxiliary fields in the ten-dimensional supersymmetric Yang-Mills theory
International Nuclear Information System (INIS)
Nilsson, B.E.W.
1986-01-01
A new way of introducing auxiliary fields into the ten-dimensional supersymmetric Yang-Mills theory is proposed. The auxiliary fields are commuting 'pure spinors' and constitute a non-linear realisation of the Lorentz group. This invalidates previous no-go theorems concerning the possibility of going off-shell in this theory. There seems to be a close relation between pure spinors and the concepts usually used in twistor theory. The non-Abelian theory can be constructed for all groups having pseudo-real representations. (author)
Energy Technology Data Exchange (ETDEWEB)
Hoff da Silva, J.M.; Rogerio, R.J.B. [Universidade Estadual Paulista, Departamento de Fisica e Quimica, Guaratingueta, SP (Brazil); Villalobos, C.H.C. [Universidade Estadual Paulista, Departamento de Fisica e Quimica, Guaratingueta, SP (Brazil); Universidade Federal Fluminense, Instituto de Fisica, Niteroi, RJ (Brazil); Rocha, Roldao da [Universidade Federal do ABC-UFABC, Centro de Matematica, Computacao e Cognicao, Santo Andre (Brazil)
2017-07-15
A systematic study of the spinor representation by means of the fermionic physical space is accomplished and implemented. The spinor representation space is shown to be constrained by the Fierz-Pauli-Kofink identities among the spinor bilinear covariants. A robust geometric and topological structure can be manifested from the spinor space, wherein the first and second homotopy groups play prominent roles on the underlying physical properties, associated to fermionic fields. The mapping that changes spinor fields classes is then exemplified, in an Einstein-Dirac system that provides the spacetime generated by a fermion. (orig.)
Spinor description of D = 5 massless low-spin gauge fields
Uvarov, D. V.
2016-07-01
Spinor description for the curvatures of D = 5 Yang-Mills, Rarita-Schwinger and gravitational fields is elaborated. Restrictions imposed on the curvature spinors by the dynamical equations and Bianchi identities are analyzed. In the absence of sources symmetric curvature spinors with 2s indices obey first-order equations that in the linearized limit reduce to Dirac-type equations for massless free fields. These equations allow for a higher-spin generalization similarly to 4d case. Their solution in the form of the integral over Lorentz-harmonic variables parametrizing coset manifold {SO}(1,4)/({SO}(1,1)× {ISO}(3)) isomorphic to the three-sphere is considered. Superparticle model that contains such Lorentz harmonics as dynamical variables, as well as harmonics parametrizing the two-sphere {SU}(2)/U(1) is proposed. The states in its spectrum are given by the functions on S 3 that upon integrating over the Lorentz harmonics reproduce on-shell symmetric curvature spinors for various supermultiplets of D = 5 space-time supersymmetry.
Population and phase dynamics of F=1 spinor condensates in an external magnetic field
International Nuclear Information System (INIS)
Romano, D.R.; Passos, E.J.V. de
2004-01-01
We show that the classical dynamics underlying the mean-field description of homogeneous mixtures of spinor F=1 Bose-Einstein condensates in an external magnetic field is integrable as a consequence of number conservation and axial symmetry in spin space. The population dynamics depends only on the quadratic term of the Zeeman energy and on the strength of the spin-dependent term of the atom-atom interaction. We determine the equilibrium populations as function of the ratio of these two quantities and the miscibility of the hyperfine components in the ground state spinors are thoroughly discussed. Outside the equilibrium, the populations are always a periodic function of time where the periodic motion can be a libration or a rotation. Our studies also indicate the absence of metastability
Nucleon-nucleon scattering in the functional quantum theory of the nonlinear spinor field
International Nuclear Information System (INIS)
Haegele, G.
1979-01-01
The author calculates the S matrix for the elastic nucleon-nucleon scattering in the lowest approximation using the quantum theory of nonlinear spinor fields with special emphasis to the ghost configuration of this theory. Introducing a general scalar product a new functional channel calculus is considered. From the results the R and T matrix elements and the differential and integral cross sections are derived. (HSI)
Some statistical aspects of the spinor field Fermi-Bose duality
Directory of Open Access Journals (Sweden)
V.M. Simulik
2012-12-01
Full Text Available The structure of 29-dimensional extended real Clifford-Dirac algebra, which has been introduced in our paper Phys. Lett. A, 2011, Vol. 375, 2479, is considered in brief. Using this algebra, the property of Fermi-Bose duality of the Dirac equation with nonzero mass is proved. It means that Dirac equation can describe not only the fermionic but also the bosonic states. The proof of our assertion based on the examples of bosonic symmetries, solutions and conservation laws is given. Some statistical aspects of the spinor field Fermi-Bose duality are discussed.
Exact spinor-scalar bound states in a quantum field theory with scalar interactions
International Nuclear Information System (INIS)
Shpytko, Volodymyr; Darewych, Jurij
2001-01-01
We study two-particle systems in a model quantum field theory in which scalar particles and spinor particles interact via a mediating scalar field. The Lagrangian of the model is reformulated by using covariant Green's functions to solve for the mediating field in terms of the particle fields. This results in a Hamiltonian in which the mediating-field propagator appears directly in the interaction term. It is shown that exact two-particle eigenstates of the Hamiltonian can be determined. The resulting relativistic fermion-boson equation is shown to have Dirac and Klein-Gordon one-particle limits. Analytical solutions for the bound state energy spectrum are obtained for the case of massless mediating fields
Approximate KMS states for scalar and spinor fields in Friedmann-Robertson-Walker spacetimes
International Nuclear Information System (INIS)
Dappiaggi, Claudio; Hack, Thomas-Paul; Pinamonti, Nicola
2010-09-01
We construct and discuss Hadamard states for both scalar and Dirac spinor fields in a large class of spatially flat Friedmann-Robertson-Walker spacetimes characterised by an initial phase either of exponential or of power-law expansion. The states we obtain can be interpreted as being in thermal equilibrium at the time when the scale factor a has a specific value a = a 0 . In the case a 0 = 0, these states fulfil a strict KMS condition on the boundary of the spacetime, which is either a cosmological horizon, or a Big Bang hypersurface. Furthermore, in the conformally invariant case, they are conformal KMS states on the full spacetime. However, they provide a natural notion of an approximate KMS state also in the remaining cases, especially for massive fields. On the technical side, our results are based on a bulk-to-boundary reconstruction technique already successfully applied in the scalar case and here proven to be suitable also for spinor fields. The potential applications of the states we find range over a broad spectrum, but they appear to be suited to discuss in particular thermal phenomena such as the cosmic neutrino background or the quantum state of dark matter. (orig.)
Approximate KMS states for scalar and spinor fields in Friedmann-Robertson-Walker spacetimes
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Dappiaggi, Claudio; Hack, Thomas-Paul [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik; Pinamonti, Nicola [Roma ' ' Tor Vergata' ' Univ. (Italy). Dipt. di Matematica
2010-09-15
We construct and discuss Hadamard states for both scalar and Dirac spinor fields in a large class of spatially flat Friedmann-Robertson-Walker spacetimes characterised by an initial phase either of exponential or of power-law expansion. The states we obtain can be interpreted as being in thermal equilibrium at the time when the scale factor a has a specific value a = a{sub 0}. In the case a{sub 0} = 0, these states fulfil a strict KMS condition on the boundary of the spacetime, which is either a cosmological horizon, or a Big Bang hypersurface. Furthermore, in the conformally invariant case, they are conformal KMS states on the full spacetime. However, they provide a natural notion of an approximate KMS state also in the remaining cases, especially for massive fields. On the technical side, our results are based on a bulk-to-boundary reconstruction technique already successfully applied in the scalar case and here proven to be suitable also for spinor fields. The potential applications of the states we find range over a broad spectrum, but they appear to be suited to discuss in particular thermal phenomena such as the cosmic neutrino background or the quantum state of dark matter. (orig.)
International Nuclear Information System (INIS)
Budinich, Paolo
2009-03-01
In a previous paper we proposed a purely mathematical way to quantum mechanics based on Cartan's simple spinors in their most elementary form of 2 components spinors. Here we proceed along that path proposing, this time, a symmetric tensor, quadrilinear in simple spinors, as a candidate for the symmetric tensor of general relativity. The procedure resembles closely that in which one builds bilinearly from simple spinors an asymmetric electromagnetic tensor, from which easily descend Maxwell's equations and the photon can be seen as a bilinear combination of neutrinos. Here Lorentzian spaces result compact, building up spheres, where hopefully the problems of the Standard Model could be solved. (author)
Spinor matter fields in SL(2,C) gauge theories of gravity: Lagrangian and Hamiltonian approaches
International Nuclear Information System (INIS)
Antonowicz, M.; Szczyrba, W.
1985-01-01
We consider the SL(2,C)-covariant Lagrangian formulation of gravitational theories with the presence of spinor matter fields. The invariance properties of such theories give rise to the conservation laws (the contracted Bianchi identities) having in the presence of matter fields a more complicated form than those known in the literature previously. A general SL(2,C) gauge theory of gravity is cast into an SL(2,C)-covariant Hamiltonian formulation. Breaking the SL(2,C) symmetry of the system to the SU(2) symmetry, by introducing a spacelike slicing of spacetime, we get an SU(2)-covariant Hamiltonian picture. The qualitative analysis of SL(2,C) gauge theories of gravity in the SU(2)-covariant formulation enables us to define the dynamical symplectic variables and the gauge variables of the theory under consideration as well as to divide the set of field equations into the dynamical equations and the constraints. In the SU(2)-covariant Hamiltonian formulation the primary constraints, which are generic for first-order matter Lagrangians (Dirac, Weyl, Fierz-Pauli), can be reduced. The effective matter symplectic variables are given by SU(2)-spinor-valued half-forms on three-dimensional slices of spacetime. The coupled Einstein-Cartan-Dirac (Weyl, Fierz-Pauli) system is analyzed from the (3+1) point of view. This analysis is complete; the field equations of the Einstein-Cartan-Dirac theory split into 18 gravitational dynamical equations, 8 dynamical Dirac equations, and 7 first-class constraints. The system has 4+8 = 12 independent degrees of freedom in the phase space
Spinor matter fields in SL(2,C) gauge theories of gravity: Lagrangian and Hamiltonian approaches
Antonowicz, Marek; Szczyrba, Wiktor
1985-06-01
We consider the SL(2,C)-covariant Lagrangian formulation of gravitational theories with the presence of spinor matter fields. The invariance properties of such theories give rise to the conservation laws (the contracted Bianchi identities) having in the presence of matter fields a more complicated form than those known in the literature previously. A general SL(2,C) gauge theory of gravity is cast into an SL(2,C)-covariant Hamiltonian formulation. Breaking the SL(2,C) symmetry of the system to the SU(2) symmetry, by introducing a spacelike slicing of spacetime, we get an SU(2)-covariant Hamiltonian picture. The qualitative analysis of SL(2,C) gauge theories of gravity in the SU(2)-covariant formulation enables us to define the dynamical symplectic variables and the gauge variables of the theory under consideration as well as to divide the set of field equations into the dynamical equations and the constraints. In the SU(2)-covariant Hamiltonian formulation the primary constraints, which are generic for first-order matter Lagrangians (Dirac, Weyl, Fierz-Pauli), can be reduced. The effective matter symplectic variables are given by SU(2)-spinor-valued half-forms on three-dimensional slices of spacetime. The coupled Einstein-Cartan-Dirac (Weyl, Fierz-Pauli) system is analyzed from the (3+1) point of view. This analysis is complete; the field equations of the Einstein-Cartan-Dirac theory split into 18 gravitational dynamical equations, 8 dynamical Dirac equations, and 7 first-class constraints. The system has 4+8=12 independent degrees of freedom in the phase space.
Introduction to 2-spinors in general relativity
O'Donnell, Peter
2003-01-01
This book deals with 2-spinors in general relativity, beginning by developing spinors in a geometrical way rather than using representation theory, which can be a little abstract. This gives the reader greater physical intuition into the way in which spinors behave. The book concentrates on the algebra and calculus of spinors connected with curved space-time. Many of the well-known tensor fields in general relativity are shown to have spinor counterparts. An analysis of the Lanczos spinor concludes the book, and some of the techniques so far encountered are applied to this. Exercises play an i
Dark energy model with spinor matter and its quintom scenario
International Nuclear Information System (INIS)
Cai Yifu; Wang Jing
2008-01-01
A class of dynamical dark energy models, dubbed spinor quintom, can be constructed by a spinor field ψ with a nontraditional potential. We find that, if choosing suitable potential, this model is able to allow the equation-of-state to cross the cosmological constant boundary without introducing any ghost fields. In a further investigation, we show that this model is able to mimic a perfect fluid of Chaplygin gas with p = -c/ρ during the evolution, and also realizes the quintom scenario with its equation-of-state across -1
Charged conformal Killing spinors
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Lischewski, Andree, E-mail: lischews@mathematik.hu-berlin.de [Humboldt-Universität zu Berlin, Institut für Mathematik, Rudower Chaussee 25, Room 1.310, D12489 Berlin (Germany)
2015-01-15
We study the twistor equation on pseudo-Riemannian Spin{sup c}-manifolds whose solutions we call charged conformal Killing spinors (CCKSs). We derive several integrability conditions for the existence of CCKS and study their relations to spinor bilinears. A construction principle for Lorentzian manifolds admitting CCKS with nontrivial charge starting from CR-geometry is presented. We obtain a partial classification result in the Lorentzian case under the additional assumption that the associated Dirac current is normal conformal and complete the classification of manifolds admitting CCKS in all dimensions and signatures ≤5 which has recently been initiated in the study of supersymmetric field theories on curved space.
Energy Technology Data Exchange (ETDEWEB)
Treder, H.J.
1976-10-01
The generally covariant Lagrangian density G = R + 2kappaL/sub matter/ of the Hamiltonian principle in general relativity, formulated by Einstein and Hilbert, can be interpreted as a functional of the potentials g/sub ik/ and Phi of the gravitational and matter fields. In this general relativistic interpretation, the Riemann-Christoffel form Gamma/sub kl//sup i/ = (/sub kl//sup i/) for the coefficients Gamma/sub kl//sup i/ of the affine connections is postulated a priori. Alternatively, one can interpret the Lagrangian G as a functional of Phi, g/sub ik/, and the coefficients Gamma/sub kl//sup i/. Then the Gamma/sub kl//sup i/ are determined by the Palatini equations. From these equations and from the symmetry Gamma/sub kl//sup i/ = Gamma/sub kl//sup i/ for all matter fields with deltaL/deltaGamma = 0 the Christoffel symbols again result. However, for Dirac's bispinor fields, deltaL/deltaGamma becomes dependent on the Dirac current, essentially with a coupling factor approx.kappadirac constant. In this case, the Palatini equations define a new transport rule for the spinor fields, according to which a second universal interaction results for the Dirac spinors, besides Einstein's gravitation. The generally covariant Dirac wave equations become the general relativistic nonlinear Heisenberg wave equations, and the second universal interaction is given by a Fermi-like interaction term of the V-A type. The geometrically induced Fermi constant is, however, very small and of the order 10/sup -81/erg cm/sup 3/.
Dirac operators and Killing spinors with torsion
International Nuclear Information System (INIS)
Becker-Bender, Julia
2012-01-01
On a Riemannian spin manifold with parallel skew torsion, we use the twistor operator to obtain an eigenvalue estimate for the Dirac operator with torsion. We consider the equality case in dimensions four and six. In odd dimensions we describe Sasaki manifolds on which equality in the estimate is realized by Killing spinors with torsion. In dimension five we characterize all Killing spinors with torsion and obtain certain naturally reductive spaces as exceptional cases.
Spins and charges in Grassmann space and Kähler spinors in space of differential forms
Borstnik, Norma Mankoc; Borstnik, Norma Mankoc; Nielsen, Holger Bech
1999-01-01
One of us got spins and charges of not only scalars and vectors but also of spinors out of fields, which are antisymmetric tensor fields. Kahler got spins of spinors out of differential forms, which again are antisymmetric tensor fields. Using our simple Grassmann formulation of spins and charges of either spinors or vectors and comparing it to the Dirac-Kahler formulation of spinors, we generalize the Dirac-Kahler approach to vector internal degrees of freedom and to charges of either spinors or vectors and tenzors and point out how at all spinors can appear in both approaches.
On the backreaction of scalar and spinor quantum fields in curved spacetimes
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Hack, Thomas-Paul
2010-10-15
In the first instance, the present work is concerned with generalising constructions and results in quantum field theory on curved spacetimes from the well-known case of the Klein-Gordon field to Dirac fields. To this end, the enlarged algebra of observables of the Dirac field is constructed in the algebraic framework. This algebra contains normal-ordered Wick polynomials in particular, and an extended analysis of one of its elements, the stress-energy tensor, is performed. Based on detailed calculations of the Hadamard coe?cients of the Dirac field, it is found that a local, covariant, and covariantly conserved construction of the stress-energy tensor is possible. Additionally, the mathematically sound Hadamard regularisation prescription of the stress-energy tensor is compared to the mathematically less rigorous DeWitt-Schwinger regularisation. It is found that both prescriptions are essentially equivalent, particularly, it turns out to be possible to formulate the DeWitt-Schwinger prescription in a well-defined way. While the aforementioned results hold in generic curved spacetimes, particular attention is also devoted to a specific class of Robertson-Walker spacetimes with a lightlike Big Bang hypersurface. Employing holographic methods, Hadamard states for the Klein-Gordon and the Dirac field are constructed. These states are preferred in the sense that they constitute asymptotic equilibrium states in the limit to the Big Bang hypersurface. Finally, solutions of the semiclassical Einstein equation for quantum fields of arbitrary spin are analysed in the flat Robertson-Walker case. One finds that these solutions explain the measured supernova Ia data as good as the {lambda}CDM model. Hence, one arrives at a natural explanation of dark energy and a simple quantum model of cosmological dark matter. (orig.)
On the backreaction of scalar and spinor quantum fields in curved spacetimes
International Nuclear Information System (INIS)
Hack, Thomas-Paul
2010-10-01
In the first instance, the present work is concerned with generalising constructions and results in quantum field theory on curved spacetimes from the well-known case of the Klein-Gordon field to Dirac fields. To this end, the enlarged algebra of observables of the Dirac field is constructed in the algebraic framework. This algebra contains normal-ordered Wick polynomials in particular, and an extended analysis of one of its elements, the stress-energy tensor, is performed. Based on detailed calculations of the Hadamard coe?cients of the Dirac field, it is found that a local, covariant, and covariantly conserved construction of the stress-energy tensor is possible. Additionally, the mathematically sound Hadamard regularisation prescription of the stress-energy tensor is compared to the mathematically less rigorous DeWitt-Schwinger regularisation. It is found that both prescriptions are essentially equivalent, particularly, it turns out to be possible to formulate the DeWitt-Schwinger prescription in a well-defined way. While the aforementioned results hold in generic curved spacetimes, particular attention is also devoted to a specific class of Robertson-Walker spacetimes with a lightlike Big Bang hypersurface. Employing holographic methods, Hadamard states for the Klein-Gordon and the Dirac field are constructed. These states are preferred in the sense that they constitute asymptotic equilibrium states in the limit to the Big Bang hypersurface. Finally, solutions of the semiclassical Einstein equation for quantum fields of arbitrary spin are analysed in the flat Robertson-Walker case. One finds that these solutions explain the measured supernova Ia data as good as the ΛCDM model. Hence, one arrives at a natural explanation of dark energy and a simple quantum model of cosmological dark matter. (orig.)
Borstnik, Norma Susana Mankoc
2008-01-01
The genuine Kaluza-Klein-like theories--with no fields in addition to gravity--have difficulties with the existence of massless spinors after the compactification of some space dimensions \\cite{witten}. We proposed in previous paper a boundary condition for spinors in d=(1+5) compactified on a flat disk that ensures masslessness of spinors (with all positive half integer charges) in d=(1+3) as well as their chiral coupling to the corresponding background gauge gravitational field. In this paper we study the same toy model, proposing a boundary condition allowing a massless spinor of one handedness and only one charge (1/2) and infinitely many massive spinors of the same charge, allowing disc to be curved. We define the operator of momentum to be Hermitean on the vector space of spinor states--the solutions on a disc with the boundary.
International Nuclear Information System (INIS)
Wilczek, F.; Zee, A.
1982-01-01
The possible utility of spinor representations of large orthogonal internal-symmetry groups is explored. The repetitive structure of families is incorporated quite naturally, but there is a difficulty with extra ''conjugate'' families having V+A weak currents. Possible methods for removing these conjugate families from the low-energy spectrum are discussed. An SO(18) example is discussed in some detail. An occurrence of spinors as a classification of composite particles is discussed. A long appendix discusses useful techniques for practical calculations involving spinors
On Action Invariance under Linear Spinor-Vector Supersymmetry
Directory of Open Access Journals (Sweden)
Kazunari Shima
2006-01-01
Full Text Available We show explicitly that a free Lagrangian expressed in terms of scalar, spinor, vector and Rarita-Schwinger (RS fields is invariant under linear supersymmetry transformations generated by a global spinor-vector parameter. A (generalized gauge invariance of the Lagrangian for the RS field is also discussed.
International Nuclear Information System (INIS)
Todorov, Ivan
2010-12-01
Expository notes on Clifford algebras and spinors with a detailed discussion of Majorana, Weyl, and Dirac spinors. The paper is meant as a review of background material, needed, in particular, in now fashionable theoretical speculations on neutrino masses. It has a more mathematical flavour than the over twenty-six-year-old Introduction to Majorana masses [M84] and includes historical notes and biographical data on past participants in the story. (author)
Quantization of a non-linearly realized supersymmetric theory
International Nuclear Information System (INIS)
Shima, Kazunari
1976-01-01
The two-dimensional version of the Volkov-Akulov's Lagrngian, where the super-symmetry is realized non-linearly by means of a single Majorana spinor psi(x), is quantized. The equal time anti-commutators for the field are not c-numbers but functions of the field itself. By the explicite calculation we shall show that supersymmetry charges of the model form the supersymmetry algebra(the graded Lie algebra) and the supersymmetry charges exactly generate a constant translation of psi(x) in the spinor space. In this work we restrict our investigation to the two-dimensional space-time for the sake of simplicity. (auth.)
Spinor Structure and Internal Symmetries
Varlamov, V. V.
2015-10-01
Spinor structure and internal symmetries are considered within one theoretical framework based on the generalized spin and abstract Hilbert space. Complex momentum is understood as a generating kernel of the underlying spinor structure. It is shown that tensor products of biquaternion algebras are associated with the each irreducible representation of the Lorentz group. Space-time discrete symmetries P, T and their combination PT are generated by the fundamental automorphisms of this algebraic background (Clifford algebras). Charge conjugation C is presented by a pseudoautomorphism of the complex Clifford algebra. This description of the operation C allows one to distinguish charged and neutral particles including particle-antiparticle interchange and truly neutral particles. Spin and charge multiplets, based on the interlocking representations of the Lorentz group, are introduced. A central point of the work is a correspondence between Wigner definition of elementary particle as an irreducible representation of the Poincaré group and SU(3)-description (quark scheme) of the particle as a vector of the supermultiplet (irreducible representation of SU(3)). This correspondence is realized on the ground of a spin-charge Hilbert space. Basic hadron supermultiplets of SU(3)-theory (baryon octet and two meson octets) are studied in this framework. It is shown that quark phenomenologies are naturally incorporated into presented scheme. The relationship between mass and spin is established. The introduced spin-mass formula and its combination with Gell-Mann-Okubo mass formula allows one to take a new look at the problem of mass spectrum of elementary particles.
An introduction to Clifford algebras and spinors
Vaz, Jayme
2016-01-01
This text explores how Clifford algebras and spinors have been sparking a collaboration and bridging a gap between Physics and Mathematics. This collaboration has been the consequence of a growing awareness of the importance of algebraic and geometric properties in many physical phenomena, and of the discovery of common ground through various touch points: relating Clifford algebras and the arising geometry to so-called spinors, and to their three definitions (both from the mathematical and physical viewpoint). The main point of contact are the representations of Clifford algebras and the periodicity theorems. Clifford algebras also constitute a highly intuitive formalism, having an intimate relationship to quantum field theory. The text strives to seamlessly combine these various viewpoints and is devoted to a wider audience of both physicists and mathematicians. Among the existing approaches to Clifford algebras and spinors this book is unique in that it provides a didactical presentation of the topic and i...
Black Holes and Exotic Spinors
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J. M. Hoff da Silva
2016-05-01
Full Text Available Exotic spin structures are non-trivial liftings, of the orthogonal bundle to the spin bundle, on orientable manifolds that admit spin structures according to the celebrated Geroch theorem. Exotic spin structures play a role of paramount importance in different areas of physics, from quantum field theory, in particular at Planck length scales, to gravity, and in cosmological scales. Here, we introduce an in-depth panorama in this field, providing black hole physics as the fount of spacetime exoticness. Black holes are then studied as the generators of a non-trivial topology that also can correspond to some inequivalent spin structure. Moreover, we investigate exotic spinor fields in this context and the way exotic spinor fields branch new physics. We also calculate the tunneling probability of exotic fermions across a Kerr-Sen black hole, showing that the exotic term does affect the tunneling probability, altering the black hole evaporation rate. Finally we show that it complies with the Hawking temperature universal law.
DEFF Research Database (Denmark)
Borstnik, N. M.; Nielsen, Holger Frits Bech
2008-01-01
all positive half integer charges) in d=(1+3) as well as their chiral coupling to the corresponding background gauge gravitational field. In this Letter we study the same toy model, proposing a boundary condition allowing a massless spinor of one handedness and only one charge (1/2) and infinitely...... Technical Rep. PRINT-83-1056, October 1983]. We proposed in [N.S. Mankoc Borštnik, H.B. Nielsen, Phys. Lett. B 633 (2006) 771, hep-th/0509101; N.S. Mankoc Borštnik, H.B. Nielsen, hep-th/0311037] a boundary condition for spinors in (1+5) compactified on a flat disk that ensures masslessness of spinors (with...... many massive spinors of the same charge, allowing disc to be curved. We define the operator of momentum to be Hermitean on the vector space of spinor states-the solutions on a disc with the boundary. Udgivelsesdato: May 22...
Quantization of a conformal invariant pure spinor model
International Nuclear Information System (INIS)
Akdeniz, K.G.; Hortacsu, M.; Pak, N.K.; Arik, M.
1982-08-01
The Gursey model, a conformally invariant pure spinor model in four dimensions, is shown to yield a renormalizable field theory, which is asymptotically free in the phase which has discrete ν 5 -invariance. (author)
Instantons and Killing spinors
Harland, Derek; Nölle, Christoph
2012-03-01
We investigate instantons on manifolds with Killing spinors and their cones. Examples of manifolds with Killing spinors include nearly Kähler 6-manifolds, nearly parallel G 2-manifolds in dimension 7, Sasaki-Einstein manifolds, and 3-Sasakian manifolds. We construct a connection on the tangent bundle over these manifolds which solves the instanton equation, and also show that the instanton equation implies the Yang-Mills equation, despite the presence of torsion. We then construct instantons on the cones over these manifolds, and lift them to solutions of heterotic supergravity. Amongst our solutions are new instantons on even-dimensional Euclidean spaces, as well as the well-known BPST, quaternionic and octonionic instantons.
On spinor geometry: A genesis of extended supersymmetry
International Nuclear Information System (INIS)
Budini, P.
1980-08-01
It is conjectured that euclidean geometry should be derived from spinor geometry through the equivalence of simple semispinor with isotropic semi n-vectors. The only tensors of complex 2n dimensional Euclidean space Esub(c)sup(2n) should then be: isotropic n - vectors and their intersections. Esub(c) 4 spinor geometry generates two isotropic semi bivectors equivalent to the semispinors of Esub(c) 4 (their geometrical properties are those of light propagating in vacuum), and their intersection: an isotropic vector (possibly representing momenta of massless particle and/or light rays); but no scalar, pseudoscalar or pseudovector is generated. In order to generate vectors outside the light cone in Msup(3.1) one needs not less than Esub(c) 6 spinor geometry which also generates Lorentz pseudoscalars and non isotropic pseudovectors and tensors. Besides, Dirac spinor should then always appear in doublets in Msup(3.1). Furthermore the mere geometrical structure of Esub(c) 6 spinor geometry seems to suggest formally, both Poincare (extended) and conformal supersymmetry. The suggested spinor-geometrical approach privileges the elementary role of semispinors. Its relevance for the real world should be manifested by the privileged role of semispinors in elementary interactions as in fact seems to be the case with Lorentz semispinors in weak interactions (and could perhaps also be the case for strong ones where conformal semispinors (or twistors) could be the interacting spinor fields). (author)
The b ghost of the pure spinor formalism is nilpotent
Energy Technology Data Exchange (ETDEWEB)
Chandia, Osvaldo, E-mail: osvaldo.chandia@uai.c [Departamento de Ciencias, Facultad de Artes Liberales and Facultad de Ingenieria y Ciencias, Universidad Adolfo Ibanez, Santiago (Chile)
2011-01-10
The ghost for world-sheet reparametrization invariance is not a fundamental field in the pure spinor formalism. It is written as a combination of pure spinor variables which have conformal dimension two and such that it commutes with the BRST operator to give the world-sheet stress tensor. We show that the ghost variable defined in this way is nilpotent since the OPE of b with itself does not have singularities.
GR angular momentum in the quadratic spinor Lagrangian formulation
Li, Siao-Jing
2016-08-01
We inquire into the question of whether the quadratic spinor Lagrangian (QSL) formulation can describe the angular momentum for a general-relativistic system. The QSL Hamiltonian has previously been shown to be able to yield an energy-momentum quasilocalization which brings a proof of the positive gravitational energy when the spinor satisfies the conformal Witten equation. After inspection, we find that, under the constraint that the spinor on the asymptotic boundary is a constant, the QSL Hamiltonian is successful in giving an angular momentum quasilocalization. We also make certain the spinor in the Hamiltonian plays the role of a gauge field, a warrant of our permission to impose constraints on the spinor. Then, by some adjustment of the QSL Hamiltonian, we gain a covariant center-of-mass moment quasilocalization only under the condition that the displacement on the asymptotic boundary is a Killing boost vector. We expect the spinor expression will bring a proof of some connection between the gravitational energy and angular momentum.
Spinor pregeometry at finite temperature
International Nuclear Information System (INIS)
Yoshimoto, Seiji.
1985-10-01
We derive the effective action for gravity at finite temperature in spinor pregeometry. The temperature-dependent effective potential for the vierbein which is parametrized as e sub(kμ) = b.diag(1, xi, xi, xi) has the minimum at b = 0 for fixed xi, and behaves as -xi 3 for fixed b. These results indicate that the system of fundamental matters in spinor pregeometry cannot be in equilibrium. (author)
Spinor and isospinor structure of relativistic particle propagators
International Nuclear Information System (INIS)
Gitman, D.M.; Shvartsman, Sh.M.
1993-07-01
Representations by means of path integrals are used to find spinor and isospinor structure of relativistic particle propagators in external fields. For Dirac propagator in an external electromagnetic field all Grassmannian integrations are performed and a general result is presented via a bosonic path integral. The spinor structure of the integrand is given explicitly by its decomposition in the independent γ-matrix structures. A similar technique is used to get the isospinor structure of the scalar particle propagator in an external non-Abelian field. (author). 21 refs
The realization of strong, stray static magnetic fields
Czech Academy of Sciences Publication Activity Database
Žežulka, Václav; Straka, Pavel
2012-01-01
Roč. 9, č. 1 (2012), s. 71-77 ISSN 1214-9705 Institutional research plan: CEZ:AV0Z30460519 Keywords : magnetic fields * magnetic circuits * permanent NdFeB magnets Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.530, year: 2011 http://www.irsm.cas.cz/materialy/acta_content/2012_01/7_Zezulka.pdf
Dirac operators and Killing spinors with torsion; Dirac-Operatoren und Killing-Spinoren mit Torsion
Energy Technology Data Exchange (ETDEWEB)
Becker-Bender, Julia
2012-12-17
On a Riemannian spin manifold with parallel skew torsion, we use the twistor operator to obtain an eigenvalue estimate for the Dirac operator with torsion. We consider the equality case in dimensions four and six. In odd dimensions we describe Sasaki manifolds on which equality in the estimate is realized by Killing spinors with torsion. In dimension five we characterize all Killing spinors with torsion and obtain certain naturally reductive spaces as exceptional cases.
Witten spinors on maximal, conformally flat hypersurfaces
International Nuclear Information System (INIS)
Frauendiener, Joerg; Nester, James M; Szabados, Laszlo B
2011-01-01
The boundary conditions that exclude zeros of the solutions of the Witten equation (and hence guarantee the existence of a 3-frame satisfying the so-called special orthonormal frame gauge conditions) are investigated. We determine the general form of the conformally invariant boundary conditions for the Witten equation, and find the boundary conditions that characterize the constant and the conformally constant spinor fields among the solutions of the Witten equations on compact domains in extrinsically and intrinsically flat, and on maximal, intrinsically globally conformally flat spacelike hypersurfaces, respectively. We also provide a number of exact solutions of the Witten equation with various boundary conditions (both at infinity and on inner or outer boundaries) that single out nowhere vanishing spinor fields on the flat, non-extreme Reissner-Nordstroem and Brill-Lindquist data sets. Our examples show that there is an interplay between the boundary conditions, the global topology of the hypersurface and the existence/non-existence of zeros of the solutions of the Witten equation.
Spinor particle creation in near extremal Reissner-Nordström black holes
Chen, Chiang-Mei; Sun, Jia-Rui; Tang, Fu-Yi; Tsai, Ping-Yen
2015-10-01
The pair production of spinor particles, which can be captured by the solution of the Dirac equation with an appropriate boundary condition, in charged black holes is investigated. We obtain the closed form of the production rate in the near extremal limit of Reissner-Nordström black holes. The cosmic censorship conjecture is seemingly guaranteed by the pair production process. Moreover, the absorption cross section ratio and retarded Green’s functions of the spinor fields calculated from the gravity side match well with those of spinor operators in the dual conformal field theory (CFT) side.
Spinors in Four-Dimensional Spaces
Torres del Castillo, Gerardo F
2010-01-01
Without using the customary Clifford algebras frequently studied in connection with the representations of orthogonal groups, this book gives an elementary introduction to the two-component spinor formalism for four-dimensional spaces with any signature. Some of the useful applications of four-dimensional spinors, such as Yang–Mills theory, are derived in detail using illustrative examples. Key topics and features: • Uniform treatment of the spinor formalism for four-dimensional spaces of any signature, not only the usual signature (+ + + −) employed in relativity • Examples taken from Riemannian geometry and special or general relativity are discussed in detail, emphasizing the usefulness of the two-component spinor formalism • Exercises in each chapter • The relationship of Clifford algebras and Dirac four-component spinors is established • Applications of the two-component formalism, focusing mainly on general relativity, are presented in the context of actual computations Spinors in Four-Dim...
Quarks as conformal semi-spinors
International Nuclear Information System (INIS)
Budini, P.
1979-07-01
The hypothesis is formulated that quarks may be represented by Cartan conformal semi-spinors. Some of the properties usually assigned to standard Dirac spinor quarks may also be assigned to semi-spinor quarks and some of them result quite simply from the geometry of semi-spinors. A charge matrix is obtained which is fractional for Cartan semi-spinors (quarks) and integer for Dirac spinors (leptons) through an orthogonal rotation in the flavour-colour plane. The angle of rotation depends on the ratio of flavour and colour coupling constants. When restricted to the νe lepton doublet, the Salam-Weinberg Lagrangian is easily obtained from the postulated hypothesis. (author)
Phantom metrics with Killing spinors
Directory of Open Access Journals (Sweden)
W.A. Sabra
2015-11-01
Full Text Available We study metric solutions of Einstein–anti-Maxwell theory admitting Killing spinors. The analogue of the IWP metric which admits a space-like Killing vector is found and is expressed in terms of a complex function satisfying the wave equation in flat (2+1-dimensional space–time. As examples, electric and magnetic Kasner spaces are constructed by allowing the solution to depend only on the time coordinate. Euclidean solutions are also presented.
A new proposal for the picture changing operators in the minimal pure spinor formalism
Bedoya, Oscar A.; Gomez, Humberto
2011-08-01
Using a new proposal for the "picture lowering" operators, we compute the tree level scattering amplitude in the minimal pure spinor formalism by performing the integration over the pure spinor space as a multidimensional Cauchy-type integral. The amplitude will be written in terms of the projective pure spinor variables, which turns out to be useful to relate rigorously the minimal and non-minimal versions of the pure spinor formalism. The natural language for relating these formalisms is the Čech-Dolbeault isomorphism. Moreover, the Dolbeault cocycle corresponding to the tree-level scattering amplitude must be evaluated in SO(10)/SU(5) instead of the whole pure spinor space, which means that the origin is removed from this space. Also, the Čech-Dolbeault language plays a key role for proving the invariance of the scattering amplitude under BRST, Lorentz and supersymmetry transformations, as well as the decoupling of unphysical states. We also relate the Green's function for the massless scalar field in ten dimensions to the tree-level scattering amplitude and comment about the scattering amplitude at higher orders. In contrast with the traditional picture lowering operators, with our new proposal the tree level scattering amplitude is independent of the constant spinors introduced to define them and the BRST exact terms decouple without integrating over these constant spinors.
Spinor calculus on 5-dimensional spacetimes
International Nuclear Information System (INIS)
Gomez-Lobo, Alfonso Garcia-Parrado; Martin-Garcia, Jose M
2010-01-01
We explain how Penrose's spinor calculus of 4-dimensional Lorentzian geometry is implemented in a 5-dimensional Lorentzian manifold. A number of issues, such as the essential spin algebra, the spin covariant derivative and the algebro-differential properties of the curvature spinors are discussed.
Directory of Open Access Journals (Sweden)
Kazuharu Bamba
2014-10-01
Full Text Available We reconstruct scalar field theories to realize inflation compatible with the BICEP2 result as well as the Planck. In particular, we examine the chaotic inflation model, natural (or axion inflation model, and an inflationary model with a hyperbolic inflaton potential. We perform an explicit approach to find out a scalar field model of inflation in which any observations can be explained in principle.
Electrodynamics: a consequence of nonlinear realizations of the Lorentz group
International Nuclear Information System (INIS)
Dalton, B.
1981-01-01
Extensions from the representations of the Lorentz group to include local nonlinear diagonal transformations is sufficient to generate, via the covariant derivative, the interaction of minimal coupling. These diagonal realizations are characterized by six functions phisub(i) which must satisfy a system of transformation equations. Inequivalent categories of solutions for the phisub(i) give rise to different electromagnetic fields. The Dirac monopole and Coulomb potentials follow directly from two different categories of these nonlinear realizations. Within this theory, charge becomes simply the nonlinear counterpart of intrinsic spin for a particular nonlinear realization of the Lorentz group. Charge is thus placed on equal footing with intrinsic spin in the sense that both phenomena can be described as consequences of our space-time symmetry. Other solutions for the six phisub(i) exist, including a spinor. The possibility that with these other solutions, these realizations could represent some other basic properties of elementary particles is discussed. (author)
Study and realization of a power circuit of a superconducting dipole generator of a magnetic field
International Nuclear Information System (INIS)
Rouanet, E.
1993-01-01
The project of experimental reactor building on controlled fusion (I.T.E.R) needed the development of a superconducting cable made of niobium-tin. Tested with a current of fifty kilo amperes under a twelve tesla constant field, this cable has to be tested under a variable field. The installation of the power circuit of the dipole field generator, consisted to the study and realization of the four following points: an important power cable; a tension protection organ of the dipole, under a seventeen milli Henrys inductance and four kilo amperes; a current regulating system given by the generator; a complete pilot system of the test station
Some basic properties of Killing spinors
International Nuclear Information System (INIS)
Hacyan, S.; Plebanski, J.
1976-01-01
The concept of Killing spinor is analyzed in a general way by using the spinorial formalism. It is shown, among other things, that higher derivatives of Killing spinors can be expressed in terms of lower order derivatives. Conformal Killing vectors are studied in some detail in the light of spinorial analysis: Classical results are formulated in terms of spinors. A theorem on Lie derivatives of Debever--Penrose vectors is proved, and it is shown that conformal motion in vacuum with zero cosmological constant must be homothetic, unless the conformal tensor vanishes or is of type N. Our results are valid for either real or complex space--time manifolds
Pitsalidis, Charalampos; Pappa, Anna-Maria; Hunter, Simon; Payne, Marcia M; Anthony, John E; Anthopoulos, Thomas D; Logothetidis, Stergios
2015-04-01
Functionalized acenes have proven to be promising compounds in the field of molecular electronics because of their unique features in terms of the stability, performance, and ease of processing. The emerging concept of large-area-compatible techniques for flexible electronics has brought about a wide variety of well-established techniques for the deposition of soluble acenes, with spray-coating representing an especially fruitful approach. In the present study, electrostatic spray deposition is proposed as an alternative to the conventional spray-coating processes, toward the realization of high-performance organic field-effect transistors (OFETs), on both rigid and flexible substrates. Particularly, a thorough study on the effect of the solvent and spraying regime on the resulting crystalline film's morphology is performed. By optimization of the process conditions in terms of control over the size as well as the crystallization scheme of the droplets, desirable morphological features along with high-quality crystal domains are obtained. The fabricated OFETs exhibit excellent electrical characteristics, with high field-effect mobility up to 0.78 cm(2)/(V s), I(on)/I(off) >10(4), and near-zero threshold voltages. Additionally, the good performance of the OFETs realized on plastic substrates gives great potentiality to the proposed method for applications in the challenging field of large-area electronics.
Directory of Open Access Journals (Sweden)
J. Buitrago
Full Text Available A new classical 2-spinor approach to U(1 gauge theory is presented in which the usual four-potential vector field is replaced by a symmetric second rank spinor. Following a lagrangian formulation, it is shown that the four-rank spinor representing the Maxwell field tensor has a U(1 local gauge invariance in terms of the electric and magnetic field strengths. When applied to the magnetic field of a monopole, this formulation, via the irreducible representation condition for the gauge group, leads to a quantization condition differing by a factor 2 of the one predicted by Dirac without relying on any kind of singular vector potentials. Finally, the U(1 invariant spinor equations, are applied to electron magnetic resonance which has many applications in the study of materials. Keywords: Weyl 2-spinor lenguage, Dirac equation, Gauge theories, Charge quantization
Disordered spinor Bose-Hubbard model
International Nuclear Information System (INIS)
LaPcki, Mateusz; Paganelli, Simone; Ahufinger, Veronica; Sanpera, Anna; Zakrzewski, Jakub
2011-01-01
We study the zero-temperature phase diagram of the disordered spin-1 Bose-Hubbard model in a two-dimensional square lattice. To this aim, we use a mean-field Gutzwiller ansatz and a probabilistic mean-field perturbation theory. The spin interaction induces two different regimes, corresponding to a ferromagnetic and antiferromagnetic order. In the ferromagnetic case, the introduction of disorder reproduces analogous features of the disordered scalar Bose-Hubbard model, consisting in the formation of a Bose glass phase between Mott insulator lobes. In the antiferromagnetic regime, the phase diagram differs more from the scalar case. Disorder in the chemical potential can lead to the disappearance of Mott insulator lobes with an odd-integer filling factor and, for sufficiently strong spin coupling, to Bose glass of singlets between even-filling Mott insulator lobes. Disorder in the spinor coupling parameter results in the appearance of a Bose glass phase only between the n and the n+1 lobes for n odd. Disorder in the scalar Hubbard interaction inhibits Mott insulator regions for occupation larger than a critical value.
Non-Gaussian statistics, classical field theory, and realizable Langevin models
International Nuclear Information System (INIS)
Krommes, J.A.
1995-11-01
The direct-interaction approximation (DIA) to the fourth-order statistic Z ∼ left-angle λψ 2 ) 2 right-angle, where λ is a specified operator and ψ is a random field, is discussed from several points of view distinct from that of Chen et al. [Phys. Fluids A 1, 1844 (1989)]. It is shown that the formula for Z DIA already appeared in the seminal work of Martin, Siggia, and Rose (Phys. Rev. A 8, 423 (1973)] on the functional approach to classical statistical dynamics. It does not follow from the original generalized Langevin equation (GLE) of Leith [J. Atmos. Sd. 28, 145 (1971)] and Kraichnan [J. Fluid Mech. 41, 189 (1970)] (frequently described as an amplitude representation for the DIA), in which the random forcing is realized by a particular superposition of products of random variables. The relationship of that GLE to renormalized field theories with non-Gaussian corrections (''spurious vertices'') is described. It is shown how to derive an improved representation, that realizes cumulants through O(ψ 4 ), by adding to the GLE a particular non-Gaussian correction. A Markovian approximation Z DIA M to Z DIA is derived. Both Z DIA and Z DIA M incorrectly predict a Gaussian kurtosis for the steady state of a solvable three-mode example
Solitons in Skyrme - Faddeev spinor model and quantum mechanics
International Nuclear Information System (INIS)
Rybakov, Y
2016-01-01
We discuss the possibility of unification of Skyrme and Faddeev approaches for the description of baryons and leptons respectively as topological solitons within the scope of 16-spinor model. The motivation for such a unification is based on a special 8- semispinor identity invented by the Italian geometrician F. Brioschi. This remarkable identity permits one to realize baryon or lepton states through the effect of spontaneous symmetry breaking emerging due to special structure of the Higgs potential in the model. At large distances from the particle - soliton small excitation of the vacuum satisfies Klein - Gordon equation with some mass that permits one to establish the correspondence with quantum mechanics in special stochastic representation of the wave function for extended particles - solitons. Finally, we illustrate the peculiar properties of stochastic representation by the famous T. Young's experiment with n slits in soliton realization. (paper)
Spinor techniques for massive fermions with arbitrary polarization
International Nuclear Information System (INIS)
Andreev, V.V.
1999-12-01
We present a new variant of spinor techniques for calculating the amplitudes of processes involving massive fermions with arbitrary polarization. It is relatively simple and leads to basic spinor products. Our procedure is riot more complex than CALCUL spinor techniques for massless fermions. We obtained spinor Chisholm identities for massive fermions. As an illustration, expressions are given for the amplitudes of elect ron- positron annihilation into fermions-pairs for several polarizations. (author)
Spinors, tensors and the covariant form of Dirac's equation
International Nuclear Information System (INIS)
Chen, W.Q.; Cook, A.H.
1986-01-01
The relations between tensors and spinors are used to establish the form of the covariant derivative of a spinor, making use of the fact that certain bilinear combinations of spinors are vectors. The covariant forms of Dirac's equation are thus obtained and examples in specific coordinate systems are displayed. (author)
Naka, S.; Toyoda, H.; Takanashi, T.; Umezawa, E.
2014-04-01
In kappa -Minkowski spacetime, the coordinates are Lie algebraic elements such that time and space coordinates do not commute, whereas space coordinates commute with each other. The noncommutativity is proportional to a Planck-length-scale constant kappa ^{-1}, which is a universal constant other than the velocity of light, under the kappa -Poincaré transformation. In this sense, the spacetime has a structure called "doubly special relativity." Such a noncommutative structure is known to be realized by SO(1,4) generators in 4-dimensional de Sitter space. In this paper, we try to construct a noncommutative spacetime having a commutative n-dimensional Minkowski spacetime based on AdS_{n+1} space with SO(2,n) symmetry. We also study an invariant wave equation corresponding to the first Casimir invariant of this symmetry as a nonlocal field equation expected to yield finite loop amplitudes.
About Twistor Spinors with Zero in Lorentzian Geometry
Directory of Open Access Journals (Sweden)
Felipe Leitner
2009-07-01
Full Text Available We describe the local conformal geometry of a Lorentzian spin manifold (M,g admitting a twistor spinor φ with zero. Moreover, we describe the shape of the zero set of φ. If φ has isolated zeros then the metric g is locally conformally equivalent to a static monopole. In the other case the zero set consists of null geodesic(s and g is locally conformally equivalent to a Brinkmann metric. Our arguments utilise tractor calculus in an essential way. The Dirac current of φ, which is a conformal Killing vector field, plays an important role for our discussion as well.
Nonadiabatic production of spinor condensates with a quadrupole-Ioffe-configuration trap
International Nuclear Information System (INIS)
Zhang, P.; Xu, Z.; You, L.
2006-01-01
Motivated by the recent experimental observation of multicomponent spinor condensates via a time-dependent quadrupole-Ioffe-configuration trap, we provide a general framework for the investigation of nonadiabatic Landau-Zener dynamics of a hyperfine spin, e.g., from an atomic magnetic dipole moment coupled to a weak time-dependent magnetic (B-) field. The spin flipped population distribution, or the so-called Majorona formula, is expressed in terms of system parameters and experimental observables; thus, the distribution provides much needed insight into the underlying mechanism for the production of spinor condensates due to nonadiabatic level crossings
Clifford algebras, spinors, spin groups and covering groups
International Nuclear Information System (INIS)
Magneville, C.; Pansart, J.P.
1991-03-01
The Dirac equation uses matrices named Υ matrices which are representations of general algebraic structures associated with a metric space. These algebras are the Clifford algebras. In the first past, these algebras are studied. Then the notion of spinor is developed. It is shown that Majorana and Weyl spinors only exist for some particular metric space. In the second part, Clifford and spinor groups are studied. They may be interpreted as the extension of the notion of orthogonal group for Clifford algebras and their spaces for representation. The rotation of a spinor is computed. In the last part, the connexion between the spinor groups and the Universal Covering Groups is presented [fr
Three-axis magnetic field induction sensor realized on buckled cantilever plate
Alfadhel, Ahmed
2013-07-01
This work presents the fabrication and characterization of a three-axis induction sensor consisting of one planar microcoil, fixed on the substrate, and two microcoils fabricated on Bbuckled cantilever plates (BCP) oriented perpendicularly to the substrate and each other. The BCP allows an out-of-plane translation while preserving a direct connection to the substrate, which aids the routing of electrical lines. The fabricated sensor is integrated on a single substrate, allowing interaction and integration with other systems. The devices are fabricated using a MEMS polymer fabrication process. Different microcoil configurations are realized with 17-30 turns, 5 μm track width, and 15-20 μm track pitch. The sensor showed up to 6.8 nT/√Hz resolution to magnetic fields within a frequency range of 40 Hz to 1 MHz. The BCP concept provides a strikingly simple method to fabricate a three-axis field sensor that can readily be integrated with electronic circuits, and the sensor\\'s performance can easily be adjusted within a wide range by changing the dimensions of the coils. © 2013 IEEE.
Directory of Open Access Journals (Sweden)
ALEX RAJ S. M.
2017-09-01
Full Text Available Underwater images raise new challenges in the field of digital image processing technology in recent years because of its widespread applications. There are many tangled matters to be considered in processing of images collected from water medium due to the adverse effects imposed by the environment itself. Image segmentation is preferred as basal stage of many digital image processing techniques which distinguish multiple segments in an image and reveal the hidden crucial information required for a peculiar application. There are so many general purpose algorithms and techniques that have been developed for image segmentation. Discontinuity based segmentation are most promising approach for image segmentation, in which Canny Edge detection based segmentation is more preferred for its high level of noise immunity and ability to tackle underwater environment. Since dealing with real time underwater image segmentation algorithm, which is computationally complex enough, an efficient hardware implementation is to be considered. The FPGA based realization of the referred segmentation algorithm is presented in this paper.
Black Hole Attractors and Pure Spinors
Energy Technology Data Exchange (ETDEWEB)
Hsu, Jonathan P.; Maloney, Alexander; Tomasiello, Alessandro
2006-02-21
We construct black hole attractor solutions for a wide class of N = 2 compactifications. The analysis is carried out in ten dimensions and makes crucial use of pure spinor techniques. This formalism can accommodate non-Kaehler manifolds as well as compactifications with flux, in addition to the usual Calabi-Yau case. At the attractor point, the charges fix the moduli according to {Sigma}f{sub k} = Im(C{Phi}), where {Phi} is a pure spinor of odd (even) chirality in IIB (A). For IIB on a Calabi-Yau, {Phi} = {Omega} and the equation reduces to the usual one. Methods in generalized complex geometry can be used to study solutions to the attractor equation.
Black Hole Attractors and Pure Spinors
International Nuclear Information System (INIS)
Hsu, Jonathan P.; Maloney, Alexander; Tomasiello, Alessandro
2006-01-01
We construct black hole attractor solutions for a wide class of N = 2 compactifications. The analysis is carried out in ten dimensions and makes crucial use of pure spinor techniques. This formalism can accommodate non-Kaehler manifolds as well as compactifications with flux, in addition to the usual Calabi-Yau case. At the attractor point, the charges fix the moduli according to Σf k = Im(CΦ), where Φ is a pure spinor of odd (even) chirality in IIB (A). For IIB on a Calabi-Yau, Φ = (Omega) and the equation reduces to the usual one. Methods in generalized complex geometry can be used to study solutions to the attractor equation
Scattering equations, supergravity integrands, and pure spinors
International Nuclear Information System (INIS)
Adamo, Tim; Casali, Eduardo
2015-01-01
The tree-level S-matrix of type II supergravity can be computed in scattering equation form by correlators in a worldsheet theory analogous to a chiral, infinite tension limit of the pure spinor formalism. By defining a non-minimal version of this theory, we give a prescription for computing correlators on higher genus worldsheets which manifest space-time supersymmetry. These correlators are conjectured to provide the loop integrands of supergravity scattering amplitudes, supported on the scattering equations. We give non-trivial evidence in support of this conjecture at genus one and two with four external states. Throughout, we find a close correspondence with the pure spinor formalism of superstring theory, particularly regarding regulators and zero-mode counting.
Scattering equations, supergravity integrands, and pure spinors
Energy Technology Data Exchange (ETDEWEB)
Adamo, Tim; Casali, Eduardo [Department of Applied Mathematics & Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)
2015-05-25
The tree-level S-matrix of type II supergravity can be computed in scattering equation form by correlators in a worldsheet theory analogous to a chiral, infinite tension limit of the pure spinor formalism. By defining a non-minimal version of this theory, we give a prescription for computing correlators on higher genus worldsheets which manifest space-time supersymmetry. These correlators are conjectured to provide the loop integrands of supergravity scattering amplitudes, supported on the scattering equations. We give non-trivial evidence in support of this conjecture at genus one and two with four external states. Throughout, we find a close correspondence with the pure spinor formalism of superstring theory, particularly regarding regulators and zero-mode counting.
Wigner function for the Dirac oscillator in spinor space
International Nuclear Information System (INIS)
Ma Kai; Wang Jianhua; Yuan Yi
2011-01-01
The Wigner function for the Dirac oscillator in spinor space is studied in this paper. Firstly, since the Dirac equation is described as a matrix equation in phase space, it is necessary to define the Wigner function as a matrix function in spinor space. Secondly, the matrix form of the Wigner function is proven to support the Dirac equation. Thirdly, by solving the Dirac equation, energy levels and the Wigner function for the Dirac oscillator in spinor space are obtained. (authors)
A formalism for the calculus of variations with spinors
International Nuclear Information System (INIS)
Bäckdahl, Thomas; Valiente Kroon, Juan A.
2016-01-01
We develop a frame and dyad gauge-independent formalism for the calculus of variations of functionals involving spinorial objects. As a part of this formalism, we define a modified variation operator which absorbs frame and spin dyad gauge terms. This formalism is applicable to both the standard spacetime (i.e., SL(2, ℂ)) 2-spinors as well as to space (i.e., SU(2, ℂ)) 2-spinors. We compute expressions for the variations of the connection and the curvature spinors
A formalism for the calculus of variations with spinors
Energy Technology Data Exchange (ETDEWEB)
Bäckdahl, Thomas, E-mail: thobac@chalmers.se [The School of Mathematics, University of Edinburgh, JCMB 6228, Peter Guthrie Tait Road, Edinburgh EH9 3FD, United Kingdom and Mathematical Sciences - Chalmers University of Technology and University of Gothenburg - SE-412 96 Gothenburg (Sweden); Valiente Kroon, Juan A., E-mail: j.a.valiente-kroon@qmul.ac.uk [School of Mathematical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS (United Kingdom)
2016-02-15
We develop a frame and dyad gauge-independent formalism for the calculus of variations of functionals involving spinorial objects. As a part of this formalism, we define a modified variation operator which absorbs frame and spin dyad gauge terms. This formalism is applicable to both the standard spacetime (i.e., SL(2, ℂ)) 2-spinors as well as to space (i.e., SU(2, ℂ)) 2-spinors. We compute expressions for the variations of the connection and the curvature spinors.
Notes on the ambitwistor pure spinor string
Czech Academy of Sciences Publication Activity Database
Lipinski Jusinskas, Renann
2016-01-01
Roč. 2016, č. 5 (2016), s. 1-12, č. článku 116. ISSN 1029-8479 R&D Projects: GA ČR GBP201/12/G028 Institutional support: RVO:68378271 Keywords : ambitwistor string * pure spinor formalism Subject RIV: BE - Theoretical Physics OBOR OECD: Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect) Impact factor: 6.063, year: 2016
Propagation of gravitational waves in the nonperturbative spinor vacuum
Energy Technology Data Exchange (ETDEWEB)
Dzhunushaliev, Vladimir [Al-Farabi Kazakh National University, Department of Theoretical and Nuclear Physics, Almaty (Kazakhstan); Al-Farabi Kazakh National University, Institute of Experimental and Theoretical Physics, Almaty (Kazakhstan); Eurasian National University, Institute for Basic Research, Astana (Kazakhstan); Institute of Physicotechnical Problems and Material Science of the NAS of the Kyrgyz Republic, Bishkek (Kyrgyzstan); Folomeev, Vladimir [Institute of Physicotechnical Problems and Material Science of the NAS of the Kyrgyz Republic, Bishkek (Kyrgyzstan)
2014-09-15
The propagation of gravitational waves on the background of a nonperturbative vacuum of a spinor field is considered. It is shown that there are several distinctive features in comparison with the propagation of plane gravitational waves through empty space: there exists a fixed phase difference between the h{sub yy,zz} and h{sub yz} components of the wave; the phase and group velocities of gravitational waves are not equal to the velocity of light; the group velocity is always less than the velocity of light; under some conditions the gravitational waves are either damped or absent; for given frequency, there exist two waves with different wave vectors. We also discuss the possibility of an experimental verification of the obtained effects as a tool to investigate nonperturbative quantum field theories. (orig.)
Non-linear realization of supersymmetry in de Sitter space
Zumino, B
1977-01-01
The author derives the non-linear transformation law and the non- linear Lagrangian for a Goldstone spinor corresponding to spontaneous breaking of global supersymmetry in a de Sitter space with O(3,2) invariance (anti de Sitter space). With a suitable choice of the Goldstone spinor field the Lagrangian agrees with the form suggested by the coupling to supergravity. The construction is also valid for the case of extended supersymmetry. (21 refs).
Parametric Amplification of Vacuum Fluctuations in a Spinor Condensate
DEFF Research Database (Denmark)
Klempt, C.; Topic, O.; Gebreyesus, G.
2010-01-01
Parametric amplification of vacuum fluctuations is crucial in modern quantum optics, enabling the creation of squeezing and entanglement. We demonstrate the parametric amplification of vacuum fluctuations for matter waves using a spinor F=2 87Rb condensate. Interatomic interactions lead...... to correlated pair creation in the mF=±1 states from an initial mF=0 condensate, which acts as a vacuum for mF≠0. Although this pair creation from a pure mF=0 condensate is ideally triggered by vacuum fluctuations, unavoidable spurious initial mF=±1 atoms induce a classical seed which may become the dominant...... triggering mechanism. We show that pair creation is insensitive to a classical seed for sufficiently large magnetic fields, demonstrating the dominant role of vacuum fluctuations. The presented system thus provides a direct path towards the generation of nonclassical states of matter....
Solitons and rogue waves in spinor Bose-Einstein condensates
Li, Sitai; Prinari, Barbara; Biondini, Gino
2018-02-01
We present a general classification of one-soliton solutions as well as families of rogue-wave solutions for F =1 spinor Bose-Einstein condensates (BECs). These solutions are obtained from the inverse scattering transform for a focusing matrix nonlinear Schrödinger equation which models condensates in the case of attractive mean-field interactions and ferromagnetic spin-exchange interactions. In particular, we show that when no background is present, all one-soliton solutions are reducible via unitary transformations to a combination of oppositely polarized solitonic solutions of single-component BECs. On the other hand, we show that when a nonzero background is present, not all matrix one-soliton solutions are reducible to a simple combination of scalar solutions. Finally, by taking suitable limits of all the solutions on a nonzero background we also obtain three families of rogue-wave (i.e., rational) solutions.
Origin of the pure spinor and Green-Schwarz formalisms
Energy Technology Data Exchange (ETDEWEB)
Berkovits, Nathan [ICTP South American Institute for Fundamental Research,Instituto de Física Teórica, UNESP - Universidade Estadual Paulista,Rua Dr. Bento T. Ferraz 271, 01140-070, São Paulo, SP (Brazil)
2015-07-20
The pure spinor formalism for the superstring was recently obtained by gauge-fixing a purely bosonic classical action involving a twistor-like constraint ∂x{sup m}(γ{sub m}λ){sub α}=0 where λ{sup α} is a d=10 pure spinor. This twistor-like constraint replaces the usual Virasoro constraint ∂x{sup m}∂x{sub m}=0, and the Green-Schwarz fermionic spacetime spinor variables θ{sup α} arise as Faddeev-Popov ghosts for this constraint. In this paper, the purely bosonic classical action is simplified by replacing the classical d=10 pure spinor λ{sup α} with a d=10 projective pure spinor. The pure spinor and Green-Schwarz formalisms for the superparticle and superstring are then obtained as different gauge-fixings of this purely bosonic classical action, and the Green-Schwarz kappa symmetry is directly related to the pure spinor BRST symmetry. Since a d=10 projective pure spinor parameterizes ((SO(10))/(U(5))), this action can be interpreted as a standard ĉ=5 topological action where one integrates over the ((SO(10))/(U(5))) choice of complex structure. Finally, a purely bosonic action for the d=11 supermembrane is proposed which reduces upon double-dimensional reduction to the purely bosonic action for the d=10 Type IIA superstring.
AdS pure spinor superstring in constant backgrounds
Energy Technology Data Exchange (ETDEWEB)
Chandia, Osvaldo [Departamento de Ciencias, Facultad de Artes Liberales, Universidad Adolfo Ibáñez,Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez,Diagonal Las Torres 2640, Peñalolén, Santiago (Chile); Bevilaqua, L. Ibiapina [Escola de Ciências e Tecnologia, Universidade Federal do Rio Grande do Norte,Caixa Postal 1524, 59072-970, Natal, RN (Brazil); Vallilo, Brenno Carlini [Facultad de Ciencias Exactas, Departamento de Ciencias Físicas, Universidad Andres Bello,Republica 220, Santiago (Chile)
2014-06-05
In this paper we study the pure spinor formulation of the superstring in AdS{sub 5}×S{sup 5} around point particle solutions of the classical equations of motion. As a particular example we quantize the pure spinor string in the BMN background.
Realization and field emission of CdSe nano-tetrapods with different arm lengths
International Nuclear Information System (INIS)
Zhao Lijuan; Pang Qi; Yang Shihe; Ge Weikun; Wang Jiannong
2009-01-01
The arms of CdSe nano-tetrapods can be greatly elongated with the core diameters and arm width unchanged by multiple injections. Room-temperature absorption and photoluminescence (PL) spectra of tetrapods with different arm lengths show that these tetrapods have almost the same core size, which is consistent with the high resolution TEM results. Field emission characteristics show that the onset field required drawing a current density of ∼0.1 μAcm -2 from CdSe nano-tetrapods with different arm lengths are 22 Vμm -1 , 9 Vμm -1 , and 4 Vμm -1 , respectively, and the field enhancement factors are determined to be about 218, 554, and 946, respectively. Results show that the longer is the arm of the tetrapods, the lower the turn-on field and the higher the field enhancement factor.
Spinor and twistor formulations of massless particles with rigidity
Energy Technology Data Exchange (ETDEWEB)
Deguchi, Shinichi, E-mail: deguchi@phys.cst.nihon-u.ac.jp [Institute of Quantum Science, College of Science and Technology, Nihon University, Chiyoda-ku, Tokyo 101-8308 (Japan); Suzuki, Takafumi [Junior College Funabashi Campus, Nihon University, Narashinodai, Funabashi, Chiba 274-8501 (Japan)
2014-04-04
The 4-dimensional model of a massless particle with rigidity whose Lagrangian is proportional to its world-line curvature is reformulated in terms of spinor and twistor variables. We begin with a first-order Lagrangian that is equivalent to the original Lagrangian proportional to the extrinsic curvature of a particle world-line. The first-order Lagrangian is written in terms of spacetime and spinor variables, leading to a spinor representation of the Lagrangian. Then its corresponding action is expressed in terms of twistor variables, leading to the gauged Shirafuji action.
Spinor formalism and complex-vector formalism of general relativity
International Nuclear Information System (INIS)
Han-ying, G.; Yong-shi, W.; Gendao, L.
1974-01-01
In this paper, using E. Cartan's exterior calculus, we give the spinor form of the structure equations, which leads naturally to the Newman--Penrose equations. Furthermore, starting from the spinor spaces and the el (2C) algebra, we construct the general complex-vector formalism of general relativity. We find that both the Cahen--Debever--Defrise complex-vector formalism and that of Brans are its special cases. Thus, the spinor formalism and the complex-vector formalism of general relativity are unified on the basis of the uni-modular group SL(2C) and its Lie algebra
Towards exact solutions of the non-linear Heisenberg-Pauli-Weyl spinor equation
International Nuclear Information System (INIS)
Mielke, E.W.
1980-03-01
In ''color geometrodynamics'' fundamental spinor fields are assumed to obey a GL(2f,C) x GL(2c,C) gauge-invariant nonlinear spinor equation of the Heisenberg-Pauli-Weyl type. Quark confinement, assimilating a scheme of Salam and Strathdee, is (partially) mediated by the tensor ''gluons'' of strong gravity. This hypothesis is incorporated into the model by considering the nonlinear Dirac equation in a curved space-time of hadronic dimensions. Disregarding internal degrees of freedom, it is then feasible, for a particular background space-time, to obtain exact solutions of the spherical bound-state problem. Finally, these solutions are tentatively interpreted as droplet-type solitons and remarks on their interrelation with Wheeler's geon construction are made. (author)
Continuous-wave solutions and modulational instability in spinor condensates of positronium
Bhat, Ishfaq Ahmad; Mithun, T.; Malomed, B. A.; Porsezian, K.
2018-02-01
We obtain general continuous-wave (CW) solutions in the model of a spinor positronium condensate in the absence of magnetic field. The CW solutions with both in-phase (n = 0) and out-of-phase (n = 1) spin components exist, with their ranges limited by the total particle density, ρ. In the limit of negligible population exchange between the spin components, the CW solutions are found to be stable or unstable, depending on the particle density of the para-positronium. Ortho-positronium, in the F = 1 spinor state, forms a ferromagnetic condensate with stable in-phase CW solutions only. Subsequent examination of the modulational instability is carried out both in the limit case of identical wavenumbers in the spin components, {{Δ }}k\\equiv {k}1-{k}-1=0, and in the more general case of {{Δ }}k\
Problems of vector Lagrangians in field theories
International Nuclear Information System (INIS)
Krivsky, I.Yu.; Simulik, V.M.
1997-01-01
A vector Lagrange approach to the Dirac spinor field and the relationship between the vector Lagrangians for the spinor and electromagnetic fields are considered. A vector Lagrange approach for the system of interacting electromagnetic B=(B μ υ)=(E-bar,H-bar) and spinor Ψ fields is constructed. New Lagrangians (scalar and vector) for electromagnetic field in terms of field strengths are found. The foundations of two new QED models are formulated
Experimental demonstration of spinor slow light
Lee, Meng-Jung; Ruseckas, Julius; Lee, Chin-Yuan; Kudriašov, Viačeslav; Chang, Kao-Fang; Cho, Hung-Wen; JuzeliÅ«nas, Gediminas; Yu, Ite A.
2016-03-01
Over the last decade there has been a continuing interest in slow and stored light based on the electromagnetically induced transparency (EIT) effect, because of their potential applications in quantum information manipulation. However, previous experimental works all dealt with the single-component slow light which cannot be employed as a qubit. In this work, we report the first experimental demonstration of two-component or spinor slow light (SSL) using a double tripod (DT) atom-light coupling scheme. The oscillations between the two components, similar to the Rabi oscillation of a two-level system or a qubit, were observed. Single-photon SSL can be considered as two-color qubits. We experimentally demonstrated a possible application of the DT scheme as quantum memory and quantum rotator for the two-color qubits. This work opens up a new direction in the slow light research.
Holomorphic field realization of SH{sup c} and quantum geometry of quiver gauge theories
Energy Technology Data Exchange (ETDEWEB)
Bourgine, Jean-Emile [INFN Bologna, Università di Bologna,Via Irnerio 46, 40126 Bologna (Italy); Matsuo, Yutaka [Department of Physics, The University of Tokyo,Hongo 7-3-1, Bunkyo-ku, Tokyo (Japan); Zhang, Hong [Department of Physics and Center for Quantum Spacetime (CQUeST),Sogang University,35 Baekbeom-ro, Mapo-gu, Seoul 04107 (Korea, Republic of)
2016-04-27
In the context of 4D/2D dualities, SH{sup c} algebra, introduced by Schiffmann and Vasserot, provides a systematic method to analyse the instanton partition functions of N=2 supersymmetric gauge theories. In this paper, we rewrite the SH{sup c} algebra in terms of three holomorphic fields D{sub 0}(z), D{sub ±1}(z) with which the algebra and its representations are simplified. The instanton partition functions for arbitrary N=2 super Yang-Mills theories with A{sub n} and A{sub n}{sup (1)} type quiver diagrams are compactly expressed as a product of four building blocks, Gaiotto state, dilatation, flavor vertex operator and intertwiner which are written in terms of SH{sup c} and the orthogonal basis introduced by Alba, Fateev, Litvinov and Tarnopolskiy. These building blocks are characterized by new conditions which generalize the known ones on the Gaiotto state and the Carlsson-Okounkov vertex. Consistency conditions of the inner product give algebraic relations for the chiral ring generating functions defined by Nekrasov, Pestun and Shatashvili. In particular we show the polynomiality of the qq-characters which have been introduced as a deformation of the Yangian characters. These relations define a second quantization of the Seiberg-Witten geometry, and, accordingly, reduce to a Baxter TQ-equation in the Nekrasov-Shatashvili limit of the Omega-background.
Type I supergravity effective action from pure spinor formalism
International Nuclear Information System (INIS)
Alencar, Geova
2009-01-01
Using the pure spinor formalism, we compute the tree-level correlation functions for three strings, one closed and two open, in N = 1 D = 10 superspace. Expanding the superfields in components, the respective terms of the effective action for the type I supergravity are obtained. All terms found agree with the effective action known in the literature. This result gives one more consistency test for the pure spinor formalism.
The naked spinor a rewrite of Clifford algebra
Morris, Dennis
2015-01-01
This book is about spinors. The whole mathematical theory of spinors is within Clifford algebra, and so this book is about Clifford algebra. Spinor theory is really the theory of empty space, and so this book is about empty space. The whole of Clifford algebra is rewritten in a much simpler form, and so the whole of spinor theory is rewritten in a much simpler form. Not only does this book make Clifford algebra simple and obvious, but it lifts the fog and mirrors from this area of mathematics to make it clear and obvious. In doing so, the true nature of spinors is revealed to the reader, and, with that, the true nature of empty space. To understand this book you will need an elementary knowledge of linear algebra (matrices) an elementary knowledge of finite groups and an elementary knowledge of the complex numbers. From no more than that, you will gain a very deep understanding of Clifford algebra, spinors, and empty space. The book is well written with all the mathematical steps laid before the reader in a w...
Cordes, V.
1983-09-01
Three solar generator projects in developing countries are discussed. A brackish water desalination unit was developed and built. A 2.4 kW solar generator supplies the desalination unit which produces 1.5 cum drinking water per day, and the pump installed for a hoisting depth of 20 m. The unit switches on if the solar energy is sufficiently high; a 160 Ahr battery guarantees constant operation. A photovoltaically supplied UHF transmitter was installed. A 3.6 kW solar generator and a battery make transmitter and air traffic warning illumination self-sufficient. A small diesel generator is installed for emergency cases. Experience shows that solar generator (4 kW) and battery have to be enlarged. An emergency solar energy generator was installed in a hospital. The solar generator has a maximum power of 150 W; together with a battery it can deliver the energy for a minimum 5 hr of emergency illumination.
Spinor Slow Light and Two-Color Qubits
Yu, Ite; Lee, Meng-Jung; Ruseckas, Julius; Lee, Chin-Yuan; Kudriasov, Viaceslav; Chang, Kao-Fang; Cho, Hung-Wen; Juzeliunas, Gediminas; Yu, Ite A.
2015-05-01
We report the first experimental demonstration of two-component or spinor slow light (SSL) using a double tripod (DT) atom-light coupling scheme. The scheme involves three atomic ground states coupled to two excited states by six light fields. The oscillation due to the interaction between the two components was observed. SSL can be used to achieve high conversion efficiencies in the sum frequency generation and is a better method than the widely-used double- Λ scheme. On the basis of the stored light, our data showed that the DT scheme behaves like the two outcomes of an interferometer enabling precision measurements of frequency detuning. Furthermore, the single-photon SSL can be considered as the qubit with the superposition state of two frequency modes or, simply, as the two-color qubit. We experimentally demonstrated a possible application of the DT scheme as quantum memory/rotator for the two-color qubit. This work opens up a new direction in the EIT/slow light research. yu@phys.nthu.edu.tw
Directory of Open Access Journals (Sweden)
Aleksandr G. Avdeiko
2017-12-01
Full Text Available The article discusses the existing forms of realization of administrative-jurisdictional powers in the field of public order protection and crime prevention. The problems of organization of activity are analyzed of commissions on juvenile affairs and protection of their rights, the administrative commissions established in municipalities. The necessity of the creation of municipal militia as a solution to the issue of the realization of local self-government bodies of administrative-jurisdictional powers
Numerical simulation of spin motion in circular accelerators using spinor formulation
International Nuclear Information System (INIS)
Nghiem, P.; Tkatchenko, A.
1992-07-01
A simple method is presented based on spinor algebra formalism for tracking the spin motion in circular accelerators. Using an analytical expression of the one-turn transformation matrix including the effects of perturbating fields or of siberian snakes, a simple and very fast numerical code has been written for studying spin motion in various circumstances. In particular, effects of synchrotron oscillations on final polarization after one isolated resonance crossing are simulated. Results of these calculations agree very well with those which have been obtained previously from analytical approaches or from other numerical-simulation programs. (author) 8 refs.; 14 figs
International Nuclear Information System (INIS)
Nous, M.H.
1983-01-01
From the theory of higher-spin fields as proposed by Bargmann-Wigner, the formulation of the fourth rank symmetric spinor psisub(abcd)(x), which describes the massive spin-2 field, is presented and discussed. The spinor is then used for the formulation of the Lagrangian and the derivation of the field equation and all the additional conditions
Null fields realizations of W3 from W (sl(4), sl(3)) and W (sl(3/1), sl(3)) algebras
International Nuclear Information System (INIS)
Bellucci, S.; Krivonos, S.; Sorin, A.
1995-09-01
It is considered the nonlinear algebras W(sl(4), sl(3)) and W(sl(3/1), sl(3)) and it is found their realizations in terms of currents spanning conformal linearizing algebras. The specific structure of these algebras, allows to construct realizations modulo null fields of the W 3 algebra that lies in the cosets W(sl(4), sl(3))/u(1) and W(sl(3/1), sl(3))/u(1). Such realizations exist for the following values of the W 3 algebra central charge: cw=-30, -40/7, -98/5, -2. The first two values are listed for the first time, whereas for the remaining values the new realizations get in terms of an arbitrary stress tensor and u(1) x sl(2) affine currents
On the pure spinor heterotic superstring b ghost
Energy Technology Data Exchange (ETDEWEB)
Fleury, Thiago [Instituto de Física Teórica, UNESP - University Estadual Paulista, ICTP South American Institute for Fundamental Research, Rua Dr. Bento Teobaldo Ferraz 271, 01140-070, São Paulo, SP (Brazil); Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5 (Canada)
2016-03-30
A simplified pure spinor superstring b ghost in a curved heterotic background was constructed recently. The b ghost is a composite operator and it is not holomorphic. However, it satisfies ∂̄b=[Q,Ω], where Q is the BRST charge. In this paper, we find a possible Ω.
Magnons interaction of spinor Bose–Einstein condensates in an ...
Indian Academy of Sciences (India)
Abstract. We study the interaction of magnons in dipolar spinor Bose–Einstein conden- sates in an optical lattice. By means of Holstein–Primakoff and Fourier transformations the energy spectra of the ground and the excited states is obtained analytically. Our results show that the collision of magnons is elastic which is ...
Spontaneous symmetry breaking in spinor Bose-Einstein condensates
DEFF Research Database (Denmark)
Scherer, Manuel; Lücke, Bernd; Peise, Jan
2013-01-01
We present an analytical model for the theoretical analysis of spin dynamics and spontaneous symmetry breaking in a spinor Bose-Einstein condensate (BEC). This allows for an excellent intuitive understanding of the processes and provides good quantitative agreement with the experimental results...
Ambitwistor pure spinor string in a type II supergravity background
Energy Technology Data Exchange (ETDEWEB)
Chandia, Osvaldo [Departamento de Ciencias, Facultad de Artes Liberales, Universidad Adolfo Ibáñez,Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez,Diagonal Las Torres 2640, Peñalolén, Santiago (Chile); Vallilo, Brenno Carlini [Departamento de Ciencias Físicas, Facultad de Ciencias Exactas, Universidad Andres Bello,República 220, Santiago (Chile)
2015-06-30
We construct the ambitwistor pure spinor string in a general type II supergravity background in the semi-classical regime. Almost all supergravity constraints are obtained from nilpotency of the BRST charge and further consistency conditions from additional world-sheet the case of AdS{sub 5}×S{sup 5} background.
Phase-space spinor amplitudes for spin-1/2 systems
International Nuclear Information System (INIS)
Watson, P.; Bracken, A. J.
2011-01-01
The concept of phase-space amplitudes for systems with continuous degrees of freedom is generalized to finite-dimensional spin systems. Complex amplitudes are obtained on both a sphere and a finite lattice, in each case enabling a more fundamental description of pure spin states than that previously given by Wigner functions. In each case the Wigner function can be expressed as the star product of the amplitude and its conjugate, so providing a generalized Born interpretation of amplitudes that emphasizes their more fundamental status. The ordinary product of the amplitude and its conjugate produces a (generalized) spin Husimi function. The case of spin-(1/2) is treated in detail, and it is shown that phase-space amplitudes on the sphere transform correctly as spinors under rotations, despite their expression in terms of spherical harmonics. Spin amplitudes on a lattice are also found to transform as spinors. Applications are given to the phase space description of state superposition, and to the evolution in phase space of the state of a spin-(1/2) magnetic dipole in a time-dependent magnetic field.
Dirac bi-spinor entanglement under local noise and its simulation by Jaynes-Cummings interactions
Bittencourt, Victor A. S. V.; Bernardini, Alex E.
2017-08-01
A description of the effects of the local noise on the quantum entanglement constraining the internal degrees of freedom of Dirac bi-spinor structures driven by arbitrary Poincaré invariant potentials is proposed. Given that the Dirac equation dynamics including external potentials can be simulated by a suitable four level trapped ion setup, quantum entanglement of two-qubit ionic states with quantum numbers related to the total angular momentum and to its projection onto the direction of the external magnetic field (used for lift the ions degeneracy), are recovered by means of a suitable ansatz. This formalism allows the inclusion of noise effects, which leads to disentanglement in the four level trapped ion quantum system. Our results indicate the role of interactions in bi-spinor entanglement, as well as the description of disentanglement in ionic states under local noises. For a state prepared initially in one of the ionic levels, local noise induces entanglement sudden death followed by sudden revivals driven by the noiseless dynamics of the state. Residual quantum correlations are observed in the intervals where such state is separable. Schrödinger cat and Werner states partially loose their initial entanglement content due to the interaction with the noisy environment but presenting entanglement oscillations without sudden death. Because Dirac equation describes low energy excitations of mono layer and bi-layer graphene, the formalism can also be applied to compute, for instance, electron-hole or electron/electron entanglement in various circumstances.
Harmonic spinors of Dirac operator of connection with torsion in dimension 4
International Nuclear Information System (INIS)
Dalakov, P.; Ivanov, S.
2000-06-01
It is shown that the existence of parallel (-)-spinor with respect to a metric connection with totally skew-symmetric torsion requires more local restriction than the existence of parallel (+)-spinor. It is proved that every harmonic spinor with respect to the Dirac operator of this connection on a compact four dimensional spin Riemannian manifold is parallel with respect to a naturally arising metric connection with totally skew-symmetric torsion and all these spaces are classified up to a conformal transformations. (author)
On the photoproduction of gravitons on spinor particles
International Nuclear Information System (INIS)
Hoang Ngoc Long; Le Khac Huong
1989-09-01
The photoproduction of the gravitons on the spinor particles in the gravitational theory is considered. In contradiction with the previous result we show that, in the low energy limit, the photon intermediate states give a main contribution in the cross-section and, in both low and high energy limits, the probability of the graviton creation is higher in the direction of the photon motion. (author). 13 refs
Field theories with subcanonical fields
International Nuclear Information System (INIS)
Bigi, I.I.Y.
1976-01-01
The properties of quantum field theories with spinor fields of dimension less than the canonical value of 3/2 are studied. As a starting point for the application of common perturbation theory we look for the linear version of these theories. A gange-interaction is introduced and with the aid of power counting the renormalizability of the theory is shown. It follows that in the case of a spinor-field with negative dimension renormalization can only be attained if the interaction has a further symmetry. By this symmetry the theory is determined in an unequivocal way. The gange-interaction introduced in the theory leads to a spontaneous breakdown of scale invariance whereby masses are produced. At the same time the spinor-field operators can now be separated in two orthogonal sections with opposite norm. It is proposed to use the section with negative (positive) norm to describe hadrons (leptons) respectively. (orig./WL) [de
Alam, Mehboob; Waqas Sumra, Muhammad; Ahmad, Daniyal; Shah, Rizwan Mustafa; Binyameen, Muhammad; Ali Shad, Sarfraz
2017-06-01
Mosquitoes are known to be vectors of numerous diseases leading to human morbidity and mortality at large scale in the world. Insecticide resistance has become a serious concern in controlling the insect vectors of public health importance. Dimethoate is an organophosphate insecticide used to control different insect pests including mosquitoes. Biological parameters of susceptible, unselected, and dimethoate-selected strains of Culex quinquefasciatus Say were studied in the laboratory to recognize resistance development potential and associated fitness cost. The dimethoate-selected strain showed 66.48-fold resistance to dimethoate compared with the susceptible strain after three continuous selections of generations. Realized heritability estimates of dimethoate resistance in Cx. quinquefasciatus yielded a value of 0.19. In dimethoate-selected strain, the biological traits including larval weight, survival from first instar to pupae, fecundity, number of next-generation larvae, relative fitness, net reproductive rate, intrinsic rate of natural increase, and biotic potential were significantly reduced as compared with the unselected strain. However, adult longevity, mean relative growth rate, weight of egg raft, female ratio, pupal duration, and emergence rate of the dimethoate-selected strain did not differ significantly compared with that of the unselected strain. This study provides useful information to devise retrospective management strategy for dimethoate resistance in Cx. quinquefasciatus. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
3+1D Massless Weyl Spinors from Bosonic Scalar-Tensor Duality
Directory of Open Access Journals (Sweden)
Andrea Amoretti
2014-01-01
Full Text Available We consider the fermionization of a bosonic-free theory characterized by the 3+1D scalar-tensor duality. This duality can be interpreted as the dimensional reduction, via a planar boundary, of the 4+1D topological BF theory. In this model, adopting the Sommerfield tomographic representation of quantized bosonic fields, we explicitly build a fermionic operator and its associated Klein factor such that it satisfies the correct anticommutation relations. Interestingly, we demonstrate that this operator satisfies the massless Dirac equation and that it can be identified with a 3+1D Weyl spinor. Finally, as an explicit example, we write the integrated charge density in terms of the tomographic transformed bosonic degrees of freedom.
Modeling a nonperturbative spinor vacuum interacting with a strong gravitational wave
Energy Technology Data Exchange (ETDEWEB)
Dzhunushaliev, Vladimir [Al-Farabi Kazakh National University, Department of Theoretical and Nuclear Physics, Almaty (Kazakhstan); Al-Farabi Kazakh National University, Institute of Experimental and Theoretical Physics, Almaty (Kazakhstan); Folomeev, Vladimir [Institute of Physicotechnical Problems and Material Science, NAS of the Kyrgyz Republic, Bishkek (Kyrgyzstan)
2015-07-15
We consider the propagation of strong gravitational waves interacting with a nonperturbative vacuum of spinor fields. To described the latter, we suggest an approximate model. The corresponding Einstein equation has the form of the Schroedinger equation. Its gravitational-wave solution is analogous to the solution of the Schroedinger equation for an electron moving in a periodic potential. The general solution for the periodic gravitational waves is found. The analog of the Kronig-Penney model for gravitational waves is considered. It is shown that the suggested gravitational-wave model permits the existence of weak electric charge and current densities concomitant with the gravitational wave. Based on this observation, a possible experimental verification of the model is suggested. (orig.)
Adak, M.; Dereli, T.
2004-05-01
A Dirac spinor is coupled to topologically massive gravity and the D = 3 dimensional action is reduced to D = 2 dimensions with a metric that includes both the electromagnetic potential 1-form A and a dilaton scalar phgr. The dimensionally reduced spinor is made a mass eigenstate with a (local) chiral rotation. The non-trivial interactions thus induced are discussed.
International Nuclear Information System (INIS)
Watabe, Shohei; Ohashi, Yoji; Kato, Yusuke
2011-01-01
We investigate tunneling properties of collective modes in the polar phase of a spin-1 spinor Bose-Einstein condensate (BEC). This spinor BEC state has two kinds of gapless modes (i.e., Bogoliubov and spin-wave). Within the framework of mean-field theory at T=0, we show that these Goldstone modes exhibit perfect transmission in the low-energy limit. Their anomalous tunneling behavior still holds in the presence of superflow, except in the critical current state. In the critical current state, while the tunneling of Bogoliubov mode is accompanied by finite reflection, the spin wave still exhibits perfect transmission, unless the strengths of spin-dependent and spin-independent interactions take the same value. We discuss the relation between perfect transmission of a spin wave and underlying superfluidity through a comparison of wave functions of the spin wave and the condensate.
Energy Technology Data Exchange (ETDEWEB)
Watabe, Shohei; Ohashi, Yoji [Department of Physics, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); CREST (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Kato, Yusuke [Department of Basic Science, University of Tokyo, Tokyo 153-8902 (Japan)
2011-07-15
We investigate tunneling properties of collective modes in the polar phase of a spin-1 spinor Bose-Einstein condensate (BEC). This spinor BEC state has two kinds of gapless modes (i.e., Bogoliubov and spin-wave). Within the framework of mean-field theory at T=0, we show that these Goldstone modes exhibit perfect transmission in the low-energy limit. Their anomalous tunneling behavior still holds in the presence of superflow, except in the critical current state. In the critical current state, while the tunneling of Bogoliubov mode is accompanied by finite reflection, the spin wave still exhibits perfect transmission, unless the strengths of spin-dependent and spin-independent interactions take the same value. We discuss the relation between perfect transmission of a spin wave and underlying superfluidity through a comparison of wave functions of the spin wave and the condensate.
The spinor heat kernel in maximally symmetric spaces
International Nuclear Information System (INIS)
Camporesi, R.
1992-01-01
The heat kernel K(x, x', t) of the iterated Dirac operator on an N-dimensional simply connected maximally symmetric Riemannian manifold is calculated. On the odd-dimensional hyperbolic spaces K is a Minakshisundaram-DeWitt expansion which terminates to the coefficient a (N-1)/2 and is exact. On the odd spheres the heat kernel may be written as an image sum of WKB kernels, each term corresponding to a classical path (geodesic). In the even dimensional case the WKB approximation is not exact, but a closed form of K is derived both in terms of (spherical) eigenfunctions and of a 'sum over classical paths'. The spinor Plancherel measure μ(λ) and ζ function in the hyperbolic case are also calculated. A simple relation between the analytic structure of μ on H N and the degeneracies of the Dirac operator on S N is found. (orig.)
Spontaneous Breaking of Spatial and Spin Symmetry in Spinor Condensates
DEFF Research Database (Denmark)
Scherer, M.; Lücke, B.; Gebreyesus, G.
2010-01-01
Parametric amplification of quantum fluctuations constitutes a fundamental mechanism for spontaneous symmetry breaking. In our experiments, a spinor condensate acts as a parametric amplifier of spin modes, resulting in a twofold spontaneous breaking of spatial and spin symmetry in the amplified...... broken, but phase squeezing prevents spin-symmetry breaking. If, however, nondegenerate spin modes contribute to the amplification, quantum interferences lead to spin-dependent density profiles and hence spontaneously formed patterns in the longitudinal magnetization....... clouds. Our experiments permit a precise analysis of the amplification in specific spatial Bessel-like modes, allowing for the detailed understanding of the double symmetry breaking. On resonances that create vortex-antivortex superpositions, we show that the cylindrical spatial symmetry is spontaneously...
Moon, Hyungbae; Yoon, Yong-Joong; Kim, Wan-Chin; Park, No-Cheol; Park, Kyoung-Su; Park, Young-Pil
2010-08-02
We report on the realization of solid immersion lens (SIL)-based near-field (NF) optics with an annular aperture, which is targeted to achieve high optical resolution. A numerical aperture (NA) = 1.84 hemisphere SIL-optics with an annular aperture achieves higher optical resolution than the conventional NA = 2.0 SIL-optics. The designed aperture is fabricated by photo-lithography and dry-etching technique. Experimental verification of the designed optics was performed through beam spot profile measurement under NF imaging conditions. A 15% smaller full-width-at-half-maximum spot diameter is obtained by the aperture. We verified that this method gives an improvement of the resolution in the optical imaging systems requiring higher resolution.
Directory of Open Access Journals (Sweden)
J. Buitrago
Full Text Available In a new classical Weyl 2-spinor approach to non abelian gauge theories, starting with the U(1 gauge group in a previous work, we study now the SU(3 case corresponding to quarks (antiquarks interacting with color fields. The principal difference with the conventional approach is that particle-field interactions are not described by means of potentials but by the field strength magnitudes. Some analytical expressions showing similarities with electrodynamics are obtained. Classical equations that describe the behavior of quarks under gluon fields might be in principle applied to the quarkâgluon plasma phase existing during the first instants of the Universe.
Directory of Open Access Journals (Sweden)
Bo Zhao
2015-09-01
Full Text Available This paper presents the design and realization of a three degrees of freedom (DOFs displacement measurement system composed of Hall sensors, which is built for the XYθz displacement measurement of the short stroke stage of the reticle stage of lithography. The measurement system consists of three pairs of permanent magnets mounted on the same plane on the short stroke stage along the Y, Y, X directions, and three single axis Hall sensors correspondingly mounted on the frame of the reticle stage. The emphasis is placed on the decoupling and magnetic field fitting of the three DOFs measurement system. The model of the measurement system is illustrated, and the XY positions and θZ rotation of the short stroke stage can be obtained by decoupling the sensor outputs. A magnetic field fitting by an elliptic function-based compensation method is proposed. The practical field intensity of a permanent magnet at a certain plane height can be substituted for the output voltage of a Hall sensors, which can be expressed by the elliptic function through experimental data as the crucial issue to calculate the three DOFs displacement. Experimental results of the Hall sensor displacement measurement system are presented to validate the proposed three DOFs measurement system.
Spinor-electron wave guided modes in coupled quantum wells structures by solving the Dirac equation
Energy Technology Data Exchange (ETDEWEB)
Linares, Jesus [Area de Optica, Departamento de Fisica Aplicada, Facultade de Fisica, Escola Universitaria de Optica e Optometria, Universidade de Santiago de Compostela, E-15782 Santiago de Compostela, Galicia (Spain)], E-mail: suso.linares.beiras@usc.es; Nistal, Maria C. [Area de Optica, Departamento de Fisica Aplicada, Facultade de Fisica, Escola Universitaria de Optica e Optometria, Universidade de Santiago de Compostela, E-15782 Santiago de Compostela, Galicia (Spain)
2009-05-04
A quantum analysis based on the Dirac equation of the propagation of spinor-electron waves in coupled quantum wells, or equivalently coupled electron waveguides, is presented. The complete optical wave equations for Spin-Up (SU) and Spin-Down (SD) spinor-electron waves in these electron guides couplers are derived from the Dirac equation. The relativistic amplitudes and dispersion equations of the spinor-electron wave-guided modes in a planar quantum coupler formed by two coupled quantum wells, or equivalently by two coupled slab electron waveguides, are exactly derived. The main outcomes related to the spinor modal structure, such as the breaking of the non-relativistic degenerate spin states, the appearance of phase shifts associated with the spin polarization and so on, are shown.
Existence of parallel spinors on non-simply-connected Riemannian manifolds
International Nuclear Information System (INIS)
McInnes, B.
1997-04-01
It is well known, and important for applications, that Ricci-flat Riemannian manifolds of non-generic holonomy always admit a parallel [covariant constant] spinor if they are simply connected. The non-simply-connected case is much more subtle, however. We show that a parallel spinor can still be found in this case provided that the [real] dimension is not a multiple of four, and provided that the spin structure is carefully chosen. (author). 10 refs
Solutions to Yang-Baxter equation for the spinor representations of q-Bl
International Nuclear Information System (INIS)
Hou Boyuan; Ma Zhongqi.
1990-10-01
In this paper, both trigonometric and rational solutions to the Yang-Baxter equation associated with the spinor representations of the quantum B l universal enveloping algebras are obtained. The corresponding representations of the braid group and the link polynomials are also computed through a standard method. The quantum Clebsch-Gordan matrix, the quantum projectors and the solutions associated with the spinor representation of the quantum B 3 are presented explicitly. (author). 16 refs, 2 tabs
Vortex creation during magnetic trap manipulations of spinor Bose-Einstein condensates
International Nuclear Information System (INIS)
Itin, A. P.; Morishita, T.; Satoh, M.; Watanabe, S.; Tolstikhin, O. I.
2006-01-01
We investigate several mechanisms of vortex creation during splitting of a spinor Bose-Einstein condensate (BEC) in a magnetic double-well trap controlled by a pair of current carrying wires and bias magnetic fields. Our study is motivated by a recent MIT experiment on splitting BECs with a similar trap [Y. Shin et al., Phys. Rev. A 72, 021604 (2005)], where an unexpected fork-like structure appeared in the interference fringes indicating the presence of a singly quantized vortex in one of the interfering condensates. It is well known that in a spin-1 BEC in a quadrupole trap, a doubly quantized vortex is topologically produced by a 'slow' reversal of bias magnetic field B z . Since in the experiment a doubly quantized vortex had never been seen, Shin et al. ruled out the topological mechanism and concentrated on the nonadiabatic mechanical mechanism for explanation of the vortex creation. We find, however, that in the magnetic trap considered both mechanisms are possible: singly quantized vortices can be formed in a spin-1 BEC topologically (for example, during the magnetic field switching-off process). We therefore provide a possible alternative explanation for the interference patterns observed in the experiment. We also present a numerical example of creation of singly quantized vortices due to 'fast' splitting; i.e., by a dynamical (nonadiabatic) mechanism
Comments on the symmetry of AdS6 solutions in string/M-theory and Killing spinor equations
Directory of Open Access Journals (Sweden)
Hyojoong Kim
2016-09-01
Full Text Available It was recently pointed out in [1] that AdS6 solutions in IIB theory enjoy an extended symmetry structure and the consistent truncation to D=4 internal space leads to a nonlinear sigma model with target SL(3,R/SO(2,1. We continue to study the purely bosonic D=4 effective action, and elucidate how the addition of scalar potential term still allows Killing spinor equations in the absence of gauge fields. In particular, the potential turns out to be a single diagonal component of the coset representative. Furthermore, we perform a general analysis of the integrability conditions of Killing spinor equations and establish that the effective action can be in fact generalized to arbitrary sizes and signatures, e.g. with target SL(n,R/SO(p,n−p and the scalar potential expressible by a single diagonal component of the coset representative. We also comment on a similar construction and its generalizations of effective D=5 purely bosonic non-linear sigma model action related to AdS6 in M-theory.
Oscillators from nonlinear realizations
Kozyrev, N.; Krivonos, S.
2018-02-01
We construct the systems of the harmonic and Pais-Uhlenbeck oscillators, which are invariant with respect to arbitrary noncompact Lie algebras. The equations of motion of these systems can be obtained with the help of the formalism of nonlinear realizations. We prove that it is always possible to choose time and the fields within this formalism in such a way that the equations of motion become linear and, therefore, reduce to ones of ordinary harmonic and Pais-Uhlenbeck oscillators. The first-order actions, that produce these equations, can also be provided. As particular examples of this construction, we discuss the so(2, 3) and G 2(2) algebras.
Magneto-optical quantum interferences in a system of spinor excitons
Kuan, Wen-Hsuan; Gudmundsson, Vidar
2018-04-01
In this work we investigate magneto-optical properties of two-dimensional semiconductor quantum-ring excitons with Rashba and Dresselhaus spin-orbit interactions threaded by a magnetic flux perpendicular to the plane of the ring. By calculating the excitonic Aharonov-Bohm spectrum, we study the Coulomb and spin-orbit effects on the Aharonov-Bohm features. From the light-matter interactions of the excitons, we find that for scalar excitons, there are open channels for spontaneous recombination resulting in a bright photoluminescence spectrum, whereas the forbidden recombination of dipolar excitons results in a dark photoluminescence spectrum. We investigate the generation of persistent charge and spin currents. The exploration of spin orientations manifests that by adjusting the strength of the spin-orbit interactions, the exciton can be constructed as a squeezed complex with specific spin polarization. Moreover, a coherently moving dipolar exciton acquires a nontrivial dual Aharonov-Casher phase, creating the possibility to generate persistent dipole currents and spin dipole currents. Our study reveals that in the presence of certain spin-orbit generated fields, the manipulation of the magnetic field provides a potential application for quantum-ring spinor excitons to be utilized in nano-scaled magneto-optical switches.
Spinor-based approach on wave processes in optical fiber
Bagmanov, Valeriy Kh.; Sultanov, Albert Kh.
2017-04-01
In this paper we introduce a novel approach for analysis of the information transmission process in mode-divisionmultiplexed (MDM) optical fiber communications. This approach is based on the representation of Maxwell's equations in the form of quantum-mechanical Schrödinger and Dirac equations. This representation allows application of the well-developed quantum electrodynamics formalism for the case of classical EM fields and reveals key properties of the optical fiber mode distribution in MDM systems following from the total angular momentum conservation law. We demonstrate the need of using coupled mode compositions instead of separate eigenmodes for realization of MDM communications based on angular momentum transfer. Such coupled modal compositions obey the law of total angular momentum conservation within spatial transformation and allow information transmission.
Resonant amplification of quantum fluctuations in a spinor gas
DEFF Research Database (Denmark)
Topic, O.; Scherer, M.; Gebreyesus, G.
2010-01-01
Bose-Einstein condensates of atoms with non-zero spin are known to constitute an ideal system to investigate fundamental properties of magnetic superfluids. More recently it was realized that they also provide the fascinating opportunity to investigate the macroscopic amplification of quantum...... and classical fluctuations. This is strikingly manifested in a sample initially prepared in the m F = 0 state, where spin-changing collisions triggered by quantum fluctuations may lead to the creation of correlated pairs in m F = ±1. We show that the pair creation efficiency is strongly influenced...... by the interplay between the external trapping potential and the Zeeman effect. It thus reflects the confinement-induced magnetic field dependence of elementary spin excitations of the condensate. Remarkably, pair production in our experiments is therefore characterized by a multi-resonant dependence...
Superradiant MeV γ Scattered by a Room-Temperature Spinor Quantum Fluid
Directory of Open Access Journals (Sweden)
Yao Cheng
2017-07-01
Full Text Available Recent reports have revealed the rich long-lived Mossbauer phenomenon of 93mNb, in which it has long been speculated that the delocalized 93mNb undergoes Bose-Einstein condensation following an increase in the 93mNb density beyond the threshold of 1012 cm−3 at room temperature. We now report on the superradiant Rayleigh of the M4 γ at 662 keV scattered into end-fire modes along the long axis of the sample, as evidence of Bose-Einstein condensation. We observed the Arago (Poisson’s spot in order to demonstrate a near-field γ-ray diffraction from a mm-sized γ source, as well as a γ interference beyond the Huygens-Fresnel principle. During the 107-day monitoring period, seven Sisyphus cycles of mode hopping appeared in the superradiance, which demonstrates the optomechanic bistabilty provided by the collective interaction between the spinor quantum fluid and the impinging γs. Condensate-light interaction produces a pm matter-wave grating to become a Fabry-Pérot resonator with a Q-factor on the order of 1020, from which end-fired γs lase.
Spinor metrics, spin connection compatibility and spacetime geometry from spin geometry
International Nuclear Information System (INIS)
Crawford, James P
2003-01-01
We show first that it is possible to consider the charge conjugation matrix as a metric (inner product) on the spin space. This metric is complementary to the usual Dirac spinor metric in that the Dirac metric defines the inner product of a spinor with a conjugate spinor, whereas the charge conjugation metric defines the inner product of a spinor with another spinor. The invariance group of the Dirac metric, U(2, 2), is distinct from that of the charge metric, Sp(4; C), but their joint subgroup, Sp(4; R), contains the cover of the Lorentz group, Sl(2; C). It is possible to find a spin connection that is metric compatible with both spin metrics, and also compatible with covariant constancy of the Dirac matrices, and this condition also then determines the spacetime curvature as the spin curvature. However, we show that if the condition of covariant constancy of the Dirac matrices is relaxed, it is possible to maintain metricity for both spin metrics, and to obtain both spacetime curvature and torsion from the spin curvature
Killing spinors for the bosonic string and Kaluza-Klein theory with scalar potentials
International Nuclear Information System (INIS)
Liu, Haishan; Lue, H.; Wang, Zhao-Long
2012-01-01
The paper consists mainly of two parts. In the first part, we obtain well-defined Killing spinor equations for the low-energy effective action of the bosonic string with the conformal anomaly term. We show that the conformal anomaly term is the only scalar potential that one can add into the action that is consistent with the Killing spinor equations. In the second part, we demonstrate that Kaluza-Klein theory can be gauged so that the Killing spinors are charged under the Kaluza-Klein vector. This gauging process generates a scalar potential with a maximum that gives rise to an AdS spacetime. We also construct solutions of these theories. (orig.)
Supersymmetry breaking effects using the pure spinor formalism of the superstring
Berkovits, Nathan; Witten, Edward
2014-06-01
The SO(32) heterotic superstring on a Calabi-Yau manifold can spontaneously break supersymmetry at one-loop order even when it is unbroken at tree-level. It is known that calculating the supersymmetry-breaking effects in this model gives a relatively accessible test case of the subtleties of superstring perturbation theory in the RNS formalism. In the present paper, we calculate the relevant amplitudes in the pure spinor approach to superstring perturbation theory, and show that the regulator used in computing loop amplitudes in the pure spinor formalism leads to subtleties somewhat analogous to the more familiar subtleties of the RNS approach.
Supersymmetry breaking effects using the pure spinor formalism of the superstring
Energy Technology Data Exchange (ETDEWEB)
Berkovits, Nathan [ICTP South American Institute for Fundamental Research,Instituto de Física Teórica, UNESP - Univ. Estadual Paulista,Rua Dr. Bento T. Ferraz 271, 01140-070, São Paulo, SP (Brazil); Witten, Edward [School of Natural Sciences, Institute for Advanced Study, Princeton, NJ 08540 (United States)
2014-06-23
The SO(32) heterotic superstring on a Calabi-Yau manifold can spontaneously break supersymmetry at one-loop order even when it is unbroken at tree-level. It is known that calculating the supersymmetry-breaking effects in this model gives a relatively accessible test case of the subtleties of superstring perturbation theory in the RNS formalism. In the present paper, we calculate the relevant amplitudes in the pure spinor approach to superstring perturbation theory, and show that the regulator used in computing loop amplitudes in the pure spinor formalism leads to subtleties somewhat analogous to the more familiar subtleties of the RNS approach.
Fujioka, Shinsuke; Arikawa, Yasunobu; Kojima, Sadaoki; Johzaki, Tomoyuki; Nagatomo, Hideo; Sawada, Hiroshi; Lee, Seung Ho; Shiroto, Takashi; Ohnishi, Naofumi; Morace, Alessio; Vaisseau, Xavier; Sakata, Shohei; Abe, Yuki; Matsuo, Kazuki; Farley Law, King Fai; Tosaki, Shota; Yogo, Akifumi; Shigemori, Keisuke; Hironaka, Yoichiro; Zhang, Zhe; Sunahara, Atsushi; Ozaki, Tetsuo; Sakagami, Hitoshi; Mima, Kunioki; Fujimoto, Yasushi; Yamanoi, Kohei; Norimatsu, Takayoshi; Tokita, Shigeki; Nakata, Yoshiki; Kawanaka, Junji; Jitsuno, Takahisa; Miyanaga, Noriaki; Nakai, Mitsuo; Nishimura, Hiroaki; Shiraga, Hiroyuki; Kondo, Kotaro; Bailly-Grandvaux, Mathieu; Bellei, Claudio; Santos, João Jorge; Azechi, Hiroshi
2016-05-01
A petawatt laser for fast ignition experiments (LFEX) laser system [N. Miyanaga et al., J. Phys. IV France 133, 81 (2006)], which is currently capable of delivering 2 kJ in a 1.5 ps pulse using 4 laser beams, has been constructed beside the GEKKO-XII laser facility for demonstrating efficient fast heating of a dense plasma up to the ignition temperature under the auspices of the Fast Ignition Realization EXperiment (FIREX) project [H. Azechi et al., Nucl. Fusion 49, 104024 (2009)]. In the FIREX experiment, a cone is attached to a spherical target containing a fuel to prevent a corona plasma from entering the path of the intense heating LFEX laser beams. The LFEX laser beams are focused at the tip of the cone to generate a relativistic electron beam (REB), which heats a dense fuel core generated by compression of a spherical deuterized plastic target induced by the GEKKO-XII laser beams. Recent studies indicate that the current heating efficiency is only 0.4%, and three requirements to achieve higher efficiency of the fast ignition (FI) scheme with the current GEKKO and LFEX systems have been identified: (i) reduction of the high energy tail of the REB; (ii) formation of a fuel core with high areal density using a limited number (twelve) of GEKKO-XII laser beams as well as a limited energy (4 kJ of 0.53-μm light in a 1.3 ns pulse); (iii) guiding and focusing of the REB to the fuel core. Laser-plasma interactions in a long-scale plasma generate electrons that are too energetic to efficiently heat the fuel core. Three actions were taken to meet the first requirement. First, the intensity contrast of the foot pulses to the main pulses of the LFEX was improved to >109. Second, a 5.5-mm-long cone was introduced to reduce pre-heating of the inner cone wall caused by illumination of the unconverted 1.053-μm light of implosion beam (GEKKO-XII). Third, the outside of the cone wall was coated with a 40-μm plastic layer to protect it from the pressure caused by imploding
Nonrelativistic counterparts of twistors and the realizations of Galilean conformal algebra
Energy Technology Data Exchange (ETDEWEB)
Fedoruk, S., E-mail: fedoruk@theor.jinr.r [Bogoliubov Laboratory of Theoretical Physics, JINR, 141980 Dubna, Moscow region (Russian Federation); Kosinski, P., E-mail: pkosinsk@uni.lodz.p [Department of Theoretical Physics II, University of Lodz, Pomorska 149/153, 90-236 Lodz (Poland); Lukierski, J., E-mail: lukier@ift.uni.wroc.p [Institute for Theoretical Physics, University of Wroclaw, pl. Maxa Borna 9, 50-204 Wroclaw (Poland); Maslanka, P., E-mail: pmaslan@uni.lodz.p [Department of Theoretical Physics II, University of Lodz, Pomorska 149/153, 90-236 Lodz (Poland)
2011-05-02
Using the notion of Galilean conformal algebra (GCA) in arbitrary space dimension d, we introduce for d=3 quantized nonrelativistic counterpart of twistors as the spinorial representation of SO(2,1)+SO(3) which is the maximal semisimple subalgebra of three-dimensional GCA. The GC-covariant quantization of such nonrelativistic spinors, which shall be called also Galilean twistors, is presented. We consider for d=3 the general spinorial matrix realizations of GCA, which are further promoted to quantum-mechanical operator representations, expressed as bilinears in quantized Galilean twistors components. For arbitrary Hermitian quantum-mechanical Galilean twistor realizations we obtain the result that the representations of GCA with positive-definite Hamiltonian do not exist. For non-positive H we construct for N{>=}2 the Hermitian Galilean N-twistor realizations of GCA; for N=2 such realization is provided explicitly.
Parametric amplification of matter waves in dipolar spinor Bose-Einstein condensates
DEFF Research Database (Denmark)
Deuretzbacher, F.; Gebreyesus, G.; Topic, O.
2010-01-01
Spin-changing collisions may lead under proper conditions to the parametric amplification of matter waves in spinor Bose-Einstein condensates. Magnetic dipole-dipole interactions, although typically very weak in alkali-metal atoms, are shown to play a very relevant role in the amplification process...
Weyl-van der Waerden spinor technic for spin-3/2 fermions
International Nuclear Information System (INIS)
Novaes, S.F.; Spehler, D.
1991-09-01
We use the Weyl-van der Waerden spinor technic to construct helicity wave functions for massless and massive spin-3/2 fermions. We apply our formalism to evaluate helicity amplitudes taking into account some phenomenological couplings involving these particles. (author)
The non-minimal heterotic pure spinor string in a curved background
Energy Technology Data Exchange (ETDEWEB)
Chandia, Osvaldo [Facultad de Artes Liberales and Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez,Diagonal Las Torres 2640, Peñalolén, Santiago (Chile)
2014-03-21
We study the non-minimal pure spinor string in a curved background. We find that the minimal BRST invariance implies the existence of a non-trivial stress-energy tensor for the minimal and non-minimal variables in the heterotic curved background. We find constraint equations for the b ghost. We construct the b ghost as a solution of these constraints.
Simplified pure spinor b ghost in a curved heterotic superstring background
Energy Technology Data Exchange (ETDEWEB)
Berkovits, Nathan [ICTP South American Institute for Fundamental Research,Instituto de Física Teórica, UNESP - Universidade Estadual Paulista,Rua Dr. Bento T. Ferraz 271, 01140-070, São Paulo, SP (Brazil); Chandia, Osvaldo [Departamento de Ciencias, Facultad de Artes Liberales,Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez,Diagonal Las Torres 2640, Peñalolén, Santiago (Chile)
2014-06-03
Using the RNS-like fermionic vector variables introduced in arXiv:1305.0693, the pure spinor b ghost in a curved heterotic superstring background is easily constructed. This construction simplifies and completes the b ghost construction in a curved background of arXiv:1311.7012.
Department of Veterans Affairs — This dataset is provided as a requirement of OMB’s Integrated Data Collection (IDC) and links to VA’s Realized Cost Savings and Avoidances data in JSON format. Cost...
International Nuclear Information System (INIS)
1986-01-01
Most typical papers on the Ganil construction have been gathered in this book to somehow notice the success of its realization. Papers concern the accelerator and beam line, excluding experimental areas
International Nuclear Information System (INIS)
Getmanov, B.S.
1988-01-01
The results of classification of two-dimensional relativistic field models (1) spinor; (2) essentially-nonlinear scalar) possessing higher conservation laws using the system of symbolic computer calculations are presented shortly
Euclidean Majorana and Dirac fields
International Nuclear Information System (INIS)
Kupsch, Joachim
1996-01-01
Euclidean Majorana fields are constructed within the Berezin calculus and as random fields on the measure space of fermionic white noise. These fields are covariant under Euclidean transformations, and their expectation values reproduce the Schwinger functions of Majorana fermions in d = 2,3,4 mod 8 dimensions. Euclidean Dirac fields and their conjugate fields can be obtained as linear functions of two independent Majorana fields by equations known from classical spinor fields on the Minkowski space. (author). 15 refs
Connection with torsion, parallel spinors and geometry of Spin(7) manifolds
International Nuclear Information System (INIS)
Ivanov, Stefan
2001-11-01
We show that on every Spin(7)-manifold there always exists a unique linear connection with totally skew-symmetric torsion preserving a nontrivial spinor and the Spin(7) structure. We express its torsion and the Riemannian scalar curvature in terms of the fundamental 4-form. We present an explicit formula for the Riemannian covariant derivative of the fundamental 4-form in terms of its exterior differential. We show the vanishing and the A-circumflex genus and obtain a linear relation between Betti numbers of a compact Spin(7) manifolds which are locally but not globally conformally equivalent to a space with closed fundamental 4-form. A general solution to the Killing spinor equations is presented. (author)
Realizing Controllable Quantum States
Takayanagi, Hideaki; Nitta, Junsaku
-- 4. Mesoscopic superconductivity with unconventional superconductor or ferromagnet. Ultraefficient microrefrigerators realized with ferromagnet-superconductor junctions / F. Giazotto et al. Anomalous charge transport in triplet superconductor junctions by the synergy effect of the proximity effect and the mid gap Andreev resonant states / Y. Tanaka and S. Kashiwaya. Paramagnetic and glass states in superconductive YBa[symbol]Cu[symbol]O[symbol] ceramics of sub-micron scale grains / H. Deguchi et al. Quantum properties of single-domain triplet superconductors / A. M. Gulian and K. S. Wood. A numerical study of Josephson current in p wave superconducting junctions / Y. Asano et al. Tilted bi-crystal sapphire substrates improve properties of grain boundary YBa[symbol]Cu[symbol]O[symbol] junctions and extend their Josephson response to THZ frequencies / E. Stepantsov et al. Circuit theory analysis of AB-plane tunnel junctions of unconventional superconductor Bi[symbol]Sr[symbol]Ca[symbol]Cu[symbol]O[symbol] / I. Shigeta et al. Transport properties of normal metal/anisotropic superconductor junctions in the eutectic system Sr[symbol]RuO[symbol]Ru / M. Kawamura et al. Macroscopic quantum tunneling in d-wave superconductor Josephson / S. Kawabata et al. Quasiparticle states of high-T[symbol] oxides observed by a Zeeman magnetic field response / S. Kashiwaya et al. Experimentally realizable devices for controlling the motion of magnetic flux quanta in anisotropic superconductors: vortex lenses, vortex diodes and vortex pumps / S. Savel'ev and F. Nori. Stability of vortex-antivortex "molecules" in mesoscopic superconducting triangles / V. R. Misko et al. Superconducting network with magnetic decoration - Hofstadter butterfly in spatially modulated magnetic field / Y. Iye et al. Observation of paramagnetic supercurrent in mesoscopic superconducting rings and disks using multiple-small-tunnel-junction method / A. Kanda et al. Guidance of vortices in high
The lattice spinor QED Hamiltonian critique of the continuous space approach
International Nuclear Information System (INIS)
Sidorov, A.V.; Zastavenko, L.G.
1993-01-01
We give the irreproachable, from the point of view of gauge invariance, derivation of the lattice spinor QED Hamiltonian. Our QED Hamiltonian is manifestly gauge invariant. We point out important defects of the continuous space formulation of the QED that make, in our opinion, the lattice QED obviously preferable to the continuous space QED. We state that it is impossible to give a continuous space QED formulation which is compatible with the condition of gauge invariance. 17 refs
DEFF Research Database (Denmark)
Barndorff-Nielsen, Ole Eiler; Hansen, P. Reinhard; Lunde, Asger
2009-01-01
Realized kernels use high-frequency data to estimate daily volatility of individual stock prices. They can be applied to either trade or quote data. Here we provide the details of how we suggest implementing them in practice. We compare the estimates based on trade and quote data for the same stock...
International Nuclear Information System (INIS)
Vash, K.
1974-01-01
The latest progress in the implementation of a joint FAO/IAEA programm in the field of food irradiation and preservation is reported. After giving a historic background to this program, the tasks facing the relevant UN agencies are listed, and the latest developments in foodstuff preservation by radiation treatment methods are presented. (E.T.)
Design and realization of simulators
International Nuclear Information System (INIS)
Mathey, C.
1984-01-01
The two main categories of simulators are training simulators of which aim is the education of the nuclear power plant operators, and the study simulators. The French park of simulators is reviewed, as also their field of utilization. One deals with the simulator design: general description, calculation tools, middleware, and programming, mathematical models and numerical methods. Then, the instructor post of the EDF's simulators are more particularly described. The realization of a simulator includes two main stages: the development of the material and, the development of the software [fr
Super-gauge field in de Sitter universe
Energy Technology Data Exchange (ETDEWEB)
Parsamehr, S.; Takook, M.V. [Islamic Azad University, Department of Physics, Science and Research Branch, Tehran (Iran, Islamic Republic of); Enayati, M. [Razi University, Department of Physics, Kermanshah (Iran, Islamic Republic of)
2016-05-15
The Gupta-Bleuler triplet for a vector-spinor gauge field is presented in the de Sitter ambient space formalism. The invariant space of field equation solutions is obtained with respect to an indecomposable representation of the de Sitter group. By using the general solution of the massless spin-(3)/(2) field equation, the vector-spinor quantum field operator and its corresponding Fock space is constructed. The quantum field operator can be written in terms of the vector-spinor polarization states and a quantum conformally coupled massless scalar field, which is constructed on Bunch-Davies vacuum state. The two-point function is also presented, which is de Sitter covariant and analytic. (orig.)
International Nuclear Information System (INIS)
Dappiagi, Claudio; Hack, Thomas-Paul; Pinamonti, Nicola
2009-03-01
We discuss from scratch the classical structure of Dirac spinors on an arbitrary globally hyperbolic, Lorentzian spacetime, their formulation as a locally covariant quantum field theory, and the associated notion of a Hadamard state. Eventually, we develop the notion of Wick polynomials for spinor fields, and we employ the latter to construct a covariantly conserved stress-energy tensor suited for back-reaction computations. We explicitly calculate its trace anomaly in particular. (orig.)
Sonmez, Bedri Gurkan; Ertop, Ozan; Mutlu, Senol
2017-09-22
We introduced a novel water-gated field effect transistor (WG-FET) which uses 16-nm-thick mono-Si film as active layer. WG-FET devices use electrical double layer (EDL) as gate insulator and operate under 1 V without causing any electrochemical reactions. Performance parameters based on voltage distribution on EDL are extracted and current-voltage relations are modelled. Both probe- and planar-gate WG-FETs with insulated and uninsulated source-drain electrodes are simulated, fabricated and tested. Best on/off ratios are measured for probe-gate devices as 23,000 A/A and 85,000 A/A with insulated and uninsulated source-drain electrodes, respectively. Planar-gate devices with source-drain insulation had inferior on/off ratio of 1,100 A/A with 600 μm gate distance and it decreased to 45 A/A when gate distance is increased to 3000 μm. Without source-drain electrode insulation, proper transistor operation is not obtained with planar-gate devices. All measurement results were in agreement with theoretical models. WG-FET is a promising device platform for microfluidic applications where sensors and read-out circuits can be integrated at transistor level.
Rushton, Simon
2016-01-01
In their hypothesis published in IJHPM, Lisa Forman and colleagues examined the prominence of the right to health and sexual and reproductive health rights (as well as related language) in four of the key reports that fed into the process of negotiating the Sustainable Development Goals (SDGs). Now that the SDGs have been formally adopted, this comment builds on some of the insights of Forman and colleagues to examine the extent to which those rights have been incorporated in SDGs 3 and 5. I argue that sexual and reproductive health rights are relatively well-covered within the SDGs. In terms of the right to health, however, the picture is much less clear. Some of the elements that make up that right are present and correct, but the SDGs have delivered no coherent vision of how a ‘right to health’ might actually be realized. An important task facing global health and human rights advocates is to continue pushing human rights framings so that progress is made both on meeting the SDGs and on realizing the right to health. PMID:27239886
General-transformation matrix for Dirac spinors and the calculation of spinorial amplitudes
International Nuclear Information System (INIS)
Nam, K.; Moravcsik, M.J.
1983-01-01
A general transformation matrix T(p's';p,s) is constructed which transforms a Dirac spinor psi(p,s) into another Dirac spinor psi(p',s') with arbitrarily given momenta and polarization states by expoloting the so-called Stech operator as one of generators for those transformations. This transformation matrix is then used in a calculation to yield the spinorial matrix element M = anti psi(p',s')GAMMApsi(p,s) for any spin polarization state. The final expressions of these matrix elements show the explicit structure of spin dependence for the process described by these spinorial amplitudes. The kinematical limiting cases such as very low energy or high energy of the various matrix elements can also be easily displayed. Our method is superior to the existing one in the following points. Since we have a well-defined transformation operator between two Dirac spinor states, we can evaluate the necessary phase factor of the matrix elements in an unambiguous way without introducing the coordinate system. This enables us to write down the Feynman amplitudes of complicated processes in any spin basis very easily in terms of previously calculated matrix elements of anti psiGAMMApsi which are building blocks of those Feynman amplitudes. The usefulness of the results is illustrated on Compton scattering and on the elastic scattering of two identical massive leptons where the phase factor is important. It is also shown that the Stech operator as a polarization operator is simply related to the operator K = #betta#(polarized μ . polarized L + 1)/2 which is often used in bound state problems
Λ( t ) cosmology induced by a slowly varying Elko field
Energy Technology Data Exchange (ETDEWEB)
Pereira, S.H.; Pinho, A.S.S.; Silva, J.M. Hoff da [Universidade Estadual Paulista (Unesp), Faculdade de Engenharia, Guaratinguetá, Departamento de Física e Química Av. Dr. Ariberto Pereira da Cunha 333, 12516-410—Guaratinguetá, SP (Brazil); Jesus, J.F., E-mail: shpereira@feg.unesp.br, E-mail: alexandre.pinho510@gmail.com, E-mail: hoff@feg.unesp.br, E-mail: jfjesus@itapeva.unesp.br [Universidade Estadual Paulista (Unesp), Campus Experimental de Itapeva, R. Geraldo Alckmin, 519 Itapeva, SP (Brazil)
2017-01-01
In this work the exact Friedmann-Robertson-Walker equations for an Elko spinor field coupled to gravity in an Einstein-Cartan framework are presented. The torsion functions coupling the Elko field spin-connection to gravity can be exactly solved and the FRW equations for the system assume a relatively simple form. In the limit of a slowly varying Elko spinor field there is a relevant contribution to the field equations acting exactly as a time varying cosmological model Λ( t )=Λ{sub *}+3β H {sup 2}, where Λ{sub *} and β are constants. Observational data using distance luminosity from magnitudes of supernovae constraint the parameters Ω {sub m} and β, which leads to a lower limit to the Elko mass. Such model mimics, then, the effects of a dark energy fluid, here sourced by the Elko spinor field. The density perturbations in the linear regime were also studied in the pseudo-Newtonian formalism.
Exact periodic and solitonic states of the spinor condensates in a uniform external potential
Energy Technology Data Exchange (ETDEWEB)
Zhang, Zhi-Hai [School of Physics and Electronics, Yancheng Teachers University, Yancheng 224051 (China); Yang, Shi-Jie, E-mail: yangshijie@tsinghua.org.cn [Department of Physics, Beijing Normal University, Beijing 100875 (China)
2016-08-15
We propose a method to analytically solve the one-dimensional coupled nonlinear Gross–Pitaevskii equations which govern the motion of the spinor Bose–Einstein condensates. In a uniform external potential, several classes of exact periodic and solitonic solutions, either in real or in complex forms, are obtained for both the F=1 and F=2 condensates for the Hamiltonian comprising the kinetic energy, the linear and the quadratic Zeeman energies. Real solutions take the form of composite soliton trains. Complex solutions correspond to the mass counter-flows as well as spin currents. These solutions are general that contains neither approximations nor constraints on the system parameters.
International Nuclear Information System (INIS)
Nous, M.H.
1983-01-01
The plane-wave solution for the fourth-rank spinor psisub(abcd)(x), which represents the massive spin-2 field, is discussed. The relativistic transformations of this field and the bilinear combinations of the components of the wave function are considered
PREFACE: Nanospintronics design and realization
Akai, Hisazumi; Katayama-Yoshida, Hiroshi; Kasai, Hideaki
2004-12-01
This special issue of Journal of Physics: Condensed Matter contains selected papers from the 1st International Conference on Nanospintronics Design and Realization (ICNDR 2004), which was held in Kyoto, Japan, 24--28 May 2004. This conference was organized by the Nanospintronics Design and Realization project members: Hideaki Kasai, Osaka (Chair of the Conference) Hisazumi Akai, Osaka Hajime Asahi, Osaka Wilson Agerico Diño, Osaka Hiroshi Harima, Kyoto Tomoyuki Kakeshita, Osaka Junjiro Kanamori, Kyoto Hiroshi Katayama-Yoshida, Osaka Koichi Kusakabe, Osaka Hiroshi Nakanishi, Osaka (Secretary) Tamio Oguchi, Hiroshima Teruo Ono, Osaka Naoshi Suzuki, Osaka Hitoshi Tabata, Osaka under the auspices of the Japan Ministry of Education, Culture, Sports, Science and Technology (MEXT) Special Coordination Funds for Promoting Science and Technology, and the sponsorship of Osaka University and the International Institute for Advanced Studies (IIAS). The conference is intended to provide an international forum for experimental and theoretical researchers, in the rapidly developing field of nanospintronics. It aims to: provide an overview of our current understanding of the physics of spin transport in (magnetic) semiconductors and hybrid magnetic/semiconductor structures; provide a venue to present and discuss the latest developments in using spin-dependent phenomena in nano-(opto-) electronics and computing applications; provide a venue for discussion and assessment of other possible means of exploiting the spin-dependent phenomena in future nano-(opto-) electronic and computing applications; address current (and foreseeable future) problems, of fundamental and applied nature, in an effort to bridge the physics and technology gap between semiconducting and magnetic materials. All of these being geared towards bringing about the realization of a functioning nanospintronics. A total of 127 delegates from 15 countries took part in ICNDR 2004, which was comprised of 62 invited
Stepwise Bose-Einstein Condensation in a Spinor Gas.
Frapolli, C; Zibold, T; Invernizzi, A; Jiménez-García, K; Dalibard, J; Gerbier, F
2017-08-04
We observe multistep condensation of sodium atoms with spin F=1, where the different Zeeman components m_{F}=0,±1 condense sequentially as the temperature decreases. The precise sequence changes drastically depending on the magnetization m_{z} and on the quadratic Zeeman energy q (QZE) in an applied magnetic field. For large QZE, the overall structure of the phase diagram is the same as for an ideal spin-1 gas, although the precise locations of the phase boundaries are significantly shifted by interactions. For small QZE, antiferromagnetic interactions qualitatively change the phase diagram with respect to the ideal case, leading, for instance, to condensation in m_{F}=±1, a phenomenon that cannot occur for an ideal gas with q>0.
Richter, Johannes; Krupnitska, Olesia; Baliha, Vasyl; Krokhmalskii, Taras; Derzhko, Oleg
2018-01-01
The search for flat-band solid-state realizations is a crucial issue to verify or to challenge theoretical predictions for quantum many-body flat-band systems. For frustrated quantum magnets flat bands lead to various unconventional properties related to the existence of localized many-magnon states. The recently synthesized magnetic compound Ba2CoSi2O6Cl2 seems to be an almost perfect candidate to observe these features in experiments. We develop a theory for Ba2CoSi2O6Cl2 by adapting the localized-magnon concept to this compound. We first show that our theory describes the known experimental facts and then we propose new experimental studies to detect a field-driven phase transition related to a Wigner-crystal-like ordering of localized magnons at low temperatures.
Exotic dual of type II double field theory
Directory of Open Access Journals (Sweden)
Eric A. Bergshoeff
2017-04-01
Full Text Available We perform an exotic dualization of the Ramond–Ramond fields in type II double field theory, in which they are encoded in a Majorana–Weyl spinor of O(D,D. Starting from a first-order master action, the dual theory in terms of a tensor–spinor of O(D,D is determined. This tensor–spinor is subject to an exotic version of the (self-duality constraint needed for a democratic formulation. We show that in components, reducing O(D,D to GL(D, one obtains the expected exotically dual theory in terms of mixed Young tableaux fields. To this end, we generalize exotic dualizations to self-dual fields, such as the 4-form in type IIB string theory.
Parametric excitation and squeezing in a many-body spinor condensate
Hoang, T. M.; Anquez, M.; Robbins, B. A.; Yang, X. Y.; Land, B. J.; Hamley, C. D.; Chapman, M. S.
2016-01-01
Atomic spins are usually manipulated using radio frequency or microwave fields to excite Rabi oscillations between different spin states. These are single-particle quantum control techniques that perform ideally with individual particles or non-interacting ensembles. In many-body systems, inter-particle interactions are unavoidable; however, interactions can be used to realize new control schemes unique to interacting systems. Here we demonstrate a many-body control scheme to coherently excite and control the quantum spin states of an atomic Bose gas that realizes parametric excitation of many-body collective spin states by time varying the relative strength of the Zeeman and spin-dependent collisional interaction energies at multiples of the natural frequency of the system. Although parametric excitation of a classical system is ineffective from the ground state, we show that in our experiment, parametric excitation from the quantum ground state leads to the generation of quantum squeezed states. PMID:27044675
Master symmetry in the AdS{sub 5}×S{sup 5} pure spinor string
Energy Technology Data Exchange (ETDEWEB)
Chandía, Osvaldo [Departamento de Ciencias, Facultad de Artes Liberales & Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez,Diagonal Las Torres 2640, Peñalolén, Santiago (Chile); III, William Divine Linch [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy,Texas A& M University,College Station, TX 77843-4242 (United States); Vallilo, Brenno Carlini [Departamento de Ciencias Físicas, Universidad Andres Bello,Sazie 2212, Santiago (Chile)
2017-01-09
We lift the set of classical non-local symmetries recently studied by Klose, Loebbert, and Münkler in the context of ℤ{sub 2} cosets to the pure spinor description of the superstring in the AdS{sub 5}×S{sup 5} background.
Realizations of polylogarithms
Wildeshaus, Jörg
1997-01-01
Classically, higher logarithms appear as multivalued functions on the projective line. Today they can be interpreted as entries of the period matrix of a certain variation of Hodge structure, itself called the "polylogarithm". The aim of the book is to document the sheaf-theoretical foundations of the field of polylogarithms. Earlier, partly unpublished results and constructions of Beilinson, Deligne, and Levin on the classical and elliptic polylog are generalized to the context of Shimura varieties. The reader is expected to have a sound background in algebraic geometry. Large parts of the book are expository, and intended as a reference for the working mathematician. Where a self-contained exposition was not possible, the author gives references in order to make the material accessible for advanced graduate students.
Realistic Realizations Of Threshold Circuits
Razavi, Hassan M.
1987-08-01
Threshold logic, in which each input is weighted, has many theoretical advantages over the standard gate realization, such as reducing the number of gates, interconnections, and power dissipation. However, because of the difficult synthesis procedure and complicated circuit implementation, their use in the design of digital systems is almost nonexistant. In this study, three methods of NMOS realizations are discussed, and their advantages and shortcomings are explored. Also, the possibility of using the methods to realize multi-valued logic is examined.
International Nuclear Information System (INIS)
Ryder, L.H.
1985-01-01
This introduction to the ideas and techniques of quantum field theory presents the material as simply as possible and is designed for graduate research students. After a brief survey of particle physics, the quantum theory of scalar and spinor fields and then of gauge fields, is developed. The emphasis throughout is on functional methods, which have played a large part in modern field theory. The book concludes with a bridge survey of ''topological'' objects in field theory and assumes a knowledge of quantum mechanics and special relativity
On the field-antifield (a)symmetry of the pure spinor superstring
Czech Academy of Sciences Publication Activity Database
Lipinski Jusinskas, Renann
2015-01-01
Roč. 2015, č. 12 (2015), s. 136 ISSN 1029-8479 R&D Projects: GA ČR GBP201/12/G028 Institutional support: RVO:68378271 Keywords : superstrings and heterotic strings * superspaces Subject RIV: BD - Theory of Information Impact factor: 6.023, year: 2015
Approximate solutions for half-dark solitons in spinor non-equilibrium Polariton condensates
Energy Technology Data Exchange (ETDEWEB)
Pinsker, Florian, E-mail: florian.pinsker@gmail.com
2015-11-15
In this work I generalize and apply an analytical approximation to analyze 1D states of non-equilibrium spinor polariton Bose–Einstein condensates (BEC). Solutions for the condensate wave functions carrying black solitons and half-dark solitons are presented. The derivation is based on the non-conservative Lagrangian formalism for complex Ginzburg–Landau type equations (cGLE), which provides ordinary differential equations for the parameters of the dark soliton solutions in their dynamic environment. Explicit expressions for the stationary dark soliton solution are stated. Subsequently the method is extended to spin sensitive polariton condensates, which yields ordinary differential equations for the parameters of half-dark solitons. Finally a stationary case with explicit expressions for half-dark solitons is presented.
Spin 3/2 field and Cartan's geometry
International Nuclear Information System (INIS)
Baaklini, N.S.
1977-02-01
The coupled spin-2-spin-3/2 system (supergravity) is expressed in Cartan's geometrical language of differential forms. The spin 3/2 field is introduced through a canonical spinor differential one-form. Two points are discussed: the introduction of higher spin fields and the origin of local supersymmetry
To the theory of quantum processes in the field of an intense electromagnetic wave
International Nuclear Information System (INIS)
Bajer, V.N.; Katkov, V.M.; Mil'shtejn, A.I.; Strakhovenko, V.M.
1975-01-01
The operator diagram technique, developed earlier for considering phenomena in a homogeneous external field, is applied to processes occurring in a plane electromagnetic wave field. Calculations are carried out on the basis of a specific technique of ''entangling'' of operator expressions. The mass operator of scalar and spinor particles determined by a double integral is found in the field of an elliptically polarized wave of a general type. Imaginary part of the operator presents a new concept of the full probability of a particle emission in a wave field. Polarization effects are analyzed for spinor particles
Realization of chiral symmetry in the ERG
International Nuclear Information System (INIS)
Echigo, Yoshio; Igarashi, Yuji
2011-01-01
We discuss within the framework of the ERG how chiral symmetry is realized in a linear σ model. A generalized Ginsparg-Wilson relation is obtained from the Ward-Takahashi identities for the Wilson action assumed to be bilinear in the Dirac fields. We construct a family of its non-perturbative solutions. The family generates the most general solutions to the Ward-Takahashi identities. Some special solutions are discussed. For each solution in this family, chiral symmetry is realized in such a way that a change in the Wilson action under non-linear symmetry transformation is canceled with a change in the functional measure. We discuss that the family of solutions reduces via a field redefinition to a family of the Wilson actions with some composite object of the scalar fields which has a simple transformation property. For this family, chiral symmetry is linearly realized with a continuum analog of the operator extension of γ 5 used on the lattice. We also show that there exist some appropriate Dirac fields which obey the standard chiral transformations with γ 5 in contrast to the lattice case. Their Yukawa interaction with scalars, however, becomes non-linear. (author)
Physical Realizations of Quantum Computing
Kanemitsu, Shigeru; Salomaa, Martti; Takagi, Shin; Are the DiVincenzo Criteria Fulfilled in 2004 ?
2006-01-01
The contributors of this volume are working at the forefront of various realizations of quantum computers. They survey the recent developments in each realization, in the context of the DiVincenzo criteria, including nuclear magnetic resonance, Josephson junctions, quantum dots, and trapped ions. There are also some theoretical contributions which have relevance in the physical realizations of a quantum computer. This book fills the gap between elementary introductions to the subject and highly specialized research papers to allow beginning graduate students to understand the cutting-edge of r
Sun, Wen-Rong; Wang, Lei
2018-01-01
To show the existence and properties of matter rogue waves in an F =1 spinor Bose-Einstein condensate (BEC), we work on the three-component Gross-Pitaevskii (GP) equations. Via the Darboux-dressing transformation, we obtain a family of rational solutions describing the extreme events, i.e. rogue waves. This family of solutions includes bright-dark-bright and bright-bright-bright rogue waves. The algebraic construction depends on Lax matrices and their Jordan form. The conditions for the existence of rogue wave solutions in an F =1 spinor BEC are discussed. For the three-component GP equations, if there is modulation instability, it is of baseband type only, confirming our analytic conditions. The energy transfers between the waves are discussed.
On semiclassical analysis of pure spinor superstring in an AdS{sub 5} x S{sup 5} background
Energy Technology Data Exchange (ETDEWEB)
Aisaka, Yuri [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Sao Paulo State Univ. (Brazil). Inst. de Fisica Teorica; Ibiapina Bevilaqua, L. [Univ. Federal do Rio Grande do Norte, Natal (Brazil). Esola de Ciencias e Tecnologia; Vallilo, Brenno C. [Santiago Univ. (Chile). Dept. de Ciencias Fisicas
2012-06-15
Relation between semiclassical analyses of Green-Schwarz and pure spinor formalisms in an AdS{sub 5} x S{sup 5} background is clarified. It is shown that the two formalisms have identical semiclassical partition functions for a simple family of classical solutions. It is also shown that, when the classical string is furthermore rigid, this in turn implies that the two formalisms predict the same one-loop corrections to spacetime energies.
Proposal and realization advertising campaign
RYCHLÁ, Marie
2008-01-01
The Bachelor Paper contains proposal and realization advertising campaign, including make charge for cost amount. The advertising campaign is made for chosen product of firm. Advertising campaign is planning by the medium of broadsheet and advertising on the Internet.
Realizations of the canonical representation
Indian Academy of Sciences (India)
A characterisation of the maximal abelian subalgebras of the bounded operators on Hilbert space that are normalised by the canonical representation of the Heisenberg group is given. This is used to classify the perfect realizations of the canonical representation.
Vortex and half-vortex dynamics in a nonlinear spinor quantum fluid.
Dominici, Lorenzo; Dagvadorj, Galbadrakh; Fellows, Jonathan M; Ballarini, Dario; De Giorgi, Milena; Marchetti, Francesca M; Piccirillo, Bruno; Marrucci, Lorenzo; Bramati, Alberto; Gigli, Giuseppe; Szymańska, Marzena H; Sanvitto, Daniele
2015-12-01
Vortices are archetypal objects that recur in the universe across the scale of complexity, from subatomic particles to galaxies and black holes. Their appearance is connected with spontaneous symmetry breaking and phase transitions. In Bose-Einstein condensates and superfluids, vortices are both point-like and quantized quasiparticles. We use a two-dimensional (2D) fluid of polaritons, bosonic particles constituted by hybrid photonic and electronic oscillations, to study quantum vortex dynamics. Polaritons benefit from easiness of wave function phase detection, a spinor nature sustaining half-integer vorticity, strong nonlinearity, and tuning of the background disorder. We can directly generate by resonant pulsed excitations a polariton condensate carrying either a full or half-integer vortex as initial condition and follow their coherent evolution using ultrafast imaging on the picosecond scale. The observations highlight a rich phenomenology, such as the spiraling of the half-vortex and the joint path of the twin charges of a full vortex, until the moment of their splitting. Furthermore, we observe the ordered branching into newly generated secondary couples, associated with the breaking of radial and azimuthal symmetries. This allows us to devise the interplay of nonlinearity and sample disorder in shaping the fluid and driving the vortex dynamics. In addition, our observations suggest that phase singularities may be seen as fundamental particles whose quantized events span from pair creation and recombination to 2D+t topological vortex strings.
The birth ofE8out of the spinors of the icosahedron.
Dechant, Pierre-Philippe
2016-01-01
E 8 is prominent in mathematics and theoretical physics, and is generally viewed as an exceptional symmetry in an eight-dimensional (8D) space very different from the space we inhabit; for instance, the Lie group E 8 features heavily in 10D superstring theory. Contrary to that point of view, here we show that the E 8 root system can in fact be constructed from the icosahedron alone and can thus be viewed purely in terms of 3D geometry. The 240 roots of E 8 arise in the 8D Clifford algebra of 3D space as a double cover of the 120 elements of the icosahedral group, generated by the root system H 3 . As a by-product, by restricting to even products of root vectors (spinors) in the 4D even subalgebra of the Clifford algebra, one can show that each 3D root system induces a root system in 4D, which turn out to also be exactly the exceptional 4D root systems. The spinorial point of view explains their existence as well as their unusual automorphism groups. This spinorial approach thus in fact allows one to construct all exceptional root systems within the geometry of three dimensions, which opens up a novel interpretation of these phenomena in terms of spinorial geometry.
Dirac spinors for doubly special relativity and κ-Minkowski noncommutative spacetime
International Nuclear Information System (INIS)
Agostini, Alessandra; Amelino-Camelia, Giovanni; Arzano, Michele
2004-01-01
We construct a Dirac equation that is consistent with one of the recently-proposed schemes for a 'doubly special relativity', a relativity with both an observer-independent velocity scale (still naturally identified with the speed-of-light constant) and an observer-independent length/momentum scale (possibly given by the Planck length/momentum). We find that the introduction of the second observer-independent scale only induces a mild deformation of the structure of Dirac spinors. We also show that our modified Dirac equation naturally arises in constructing a Dirac equation in the κ-Minkowski noncommutative spacetime. Previous, more heuristic studies had already argued for a possible role of doubly special relativity in κ-Minkowski, but remained vague on the nature of the consistency requirements that should be implemented in order to assure the observer-independence of the two scales. We find that a key role is played by the choice of a differential calculus in κ-Minkowski. A much-studied choice of the differential calculus does lead to our doubly special relativity Dirac equation, but a different scenario is encountered for another popular choice of differential calculus
Acoustic wave science realized by metamaterials.
Lee, Dongwoo; Nguyen, Duc Minh; Rho, Junsuk
2017-01-01
Artificially structured materials with unit cells at sub-wavelength scale, known as metamaterials, have been widely used to precisely control and manipulate waves thanks to their unconventional properties which cannot be found in nature. In fact, the field of acoustic metamaterials has been much developed over the past 15 years and still keeps developing. Here, we present a topical review of metamaterials in acoustic wave science. Particular attention is given to fundamental principles of acoustic metamaterials for realizing the extraordinary acoustic properties such as negative, near-zero and approaching-infinity parameters. Realization of acoustic cloaking phenomenon which is invisible from incident sound waves is also introduced by various approaches. Finally, acoustic lenses are discussed not only for sub-diffraction imaging but also for applications based on gradient index (GRIN) lens.
Covariant representations of massless Fermi fields
International Nuclear Information System (INIS)
Borek, R.
1983-01-01
The author shows in the framework of algebraic quantum field theory that representations of the quasi-local algebra of a free, massless spinor field exist which fulfil two axioms of von Neumann. Furthermore, the current algebra of a charged, massless fermion is considered. Finally, representations with the spectral condition of a charged, massless fermion and the quasi-local algebra of a free, massless Majorana particle are constructed. (HSI) [de
PRAGMATIC TRANSFER IN REQUEST REALIZATIONS
Directory of Open Access Journals (Sweden)
Indawan Syahri
2007-01-01
Full Text Available This study investigates the pragmatic transfer in English request realizations made by EFL learners, i.e. the proficient learners. The subjects were students of an English Study Program who obtained TOEFL-like scores of at least 450. The data were collected by means of DCT-questionnaires and Role-plays. The results show that the subjects realize requests in the form of external modifications more frequently. Most of them embed their requests with supportive moves dominantly. They enfold the acts with the moves before, after or in both positions. Of the three positions, they mostly insert the moves initial position, i.e., through inductive patterns. This is due to pragmatic transfer.
Realizations of the canonical representation
Indian Academy of Sciences (India)
Note that the symplectic group Sp(2n, R)acts onR2n preservinge. ... Observe that a maximal inductive algebra is weakly closed. DEFINITION 2.3 ... Let E be a perfect realization over (B, μ). Let B be a standard G-space. Suppose f : B → B is a Borel G-map. Set μ = f∗μ. Then μ is G-quasi-invariant. Sup- pose μ is σ-finite.
Realizations of the canonical representation
Indian Academy of Sciences (India)
Sup- pose μ is σ-finite. We get a G-quasi-equivariant disintegration λb of μ over μ . Set ... For the proof of existence of a disintegration, see Theorem 7.1 of [3]. DEFINITION 2.9. A perfect realization E is minimal if ... certain family of Hilbert spaces (in fact, a line bundle) over R2n/M. It is not hard to see that E is a minimal perfect ...
Realization of Environmental Targets. Progress Report 2008
International Nuclear Information System (INIS)
Hoen, A.; Kruitwagen, S.
2008-01-01
35 indicators that link up to the articles from the VROM budget are used to describe current developments in the field of the environment. It is also indicated whether the Netherlands will meet the national and European obligatory environmental objectives. This report shows that the trends in environmental stress and environmental quality are positive. Some exceptions are the trend of the energy saving pace and the CO2 emission of traffic and transport. Contrary to the generally favorable trends there is also much uncertainty for many environmental dossiers whether the established objectives can be realized in time. [mk] [nl
Democracy of internal symmetries in supersymmetrical quantum field theory
Energy Technology Data Exchange (ETDEWEB)
Lopuszanski, J.T.
1981-12-01
The freedom of choice of some discrete and internal symmetries in the supersymmetric, massive, interacting quantum field theory is discussed. It is shown that the discrete symmetry consisting of changing the sign of some (not all) scalar fields is incompatible with the supersymmetric structure of the theory. It is further demonstrated that an internal symmetry which transforms only some of the fields of fixed spin leaving the other fields invariant and which acts nontrivially on the supercharges can not be admitted as a symmetry; although it can be a good internal symmetry in absence of supersymmetric covariance. Moreover, in case of a model consisting of scalar, spinor and vector fields even a symmetry which transforms all of the scalar (vector) fields leaving spinor and vector (scalar) fields unaffected is ruled out provided it acts nontrivially on some of the supercharges.
N=2, 4 supersymmetric gauge field theory in two-time physics
International Nuclear Information System (INIS)
Bars, Itzhak; Kuo, Y.-C.
2009-01-01
In the context of two-time physics in 4+2 dimensions we construct the most general N=2, 4 supersymmetric Yang-Mills gauge theories for any gauge group G. This builds on our previous work for N=1 supersymmetry (SUSY). The action, the conserved SUSY currents, and the SU(N) covariant SUSY transformation laws are presented for both N=2 and N=4. When the equations of motion are used the SUSY transformations close to the supergroup SU(2,2|N) with N=1, 2, 4. The SU(2,2)=SO(4,2) subsymmetry is realized linearly on 4+2 dimensional flat spacetime. All fields, including vectors and spinors, are in 4+2 dimensions. The extra gauge symmetries in 2T field theory, together with the kinematic constraints that follow from the action, remove all the ghosts to give a unitary theory. By choosing gauges and solving the kinematic equations, the 2T field theory in 4+2 flat spacetime can be reduced to various shadows in various 3+1 dimensional (generally curved) spacetimes. These shadows are related to each other by dualities. The conformal shadows of our theories in flat 3+1 dimensions coincide with the well known counterpart N=1, 2, 4 supersymmetric massless renormalizable field theories in 3+1 dimensions. It is expected that our more symmetric new structures in 4+2 spacetime may be useful for nonperturbative or exact solutions of these theories.
Realizing the Haldane Phase with Bosons in Optical Lattices
Xu, Junjun; Gu, Qiang; Mueller, Erich J.
2018-02-01
We analyze an experimentally realizable model of bosons in a zigzag optical lattice, showing that, by rapidly modulating the magnetic field, one can tune interaction parameters and realize an analog of the Haldane phase. We explain how quantum gas microscopy can be used to detect this phase's nonlocal string order and its topological edge states. We model the detection process. We also find that this model can display supersolid correlations, but argue that they only occur at parameter values which would be challenging to realize in an experiment.
Covariant extensions and the nonsymmetric unified field
International Nuclear Information System (INIS)
Borchsenius, K.
1976-01-01
The problem of generally covariant extension of Lorentz invariant field equations, by means of covariant derivatives extracted from the nonsymmetric unified field, is considered. It is shown that the contracted curvature tensor can be expressed in terms of a covariant gauge derivative which contains the gauge derivative corresponding to minimal coupling, if the universal constant p, characterizing the nonsymmetric theory, is fixed in terms of Planck's constant and the elementary quantum of charge. By this choice the spinor representation of the linear connection becomes closely related to the spinor affinity used by Infeld and Van Der Waerden (Sitzungsber. Preuss. Akad. Wiss. Phys. Math. Kl.; 9:380 (1933)) in their generally covariant formulation of Dirac's equation. (author)
Massless conformal fields, AdS(d+1/CFTd higher spin algebras and their deformations
Directory of Open Access Journals (Sweden)
Sudarshan Fernando
2016-03-01
Full Text Available We extend our earlier work on the minimal unitary representation of SO(d,2 and its deformations for d=4,5 and 6 to arbitrary dimensions d. We show that there is a one-to-one correspondence between the minrep of SO(d,2 and its deformations and massless conformal fields in Minkowskian spacetimes in d dimensions. The minrep describes a massless conformal scalar field, and its deformations describe massless conformal fields of higher spin. The generators of Joseph ideal vanish identically as operators for the quasiconformal realization of the minrep, and its enveloping algebra yields directly the standard bosonic AdS(d+1/CFTd higher spin algebra. For deformed minreps the generators of certain deformations of Joseph ideal vanish as operators and their enveloping algebras lead to deformations of the standard bosonic higher spin algebra. In odd dimensions there is a unique deformation of the higher spin algebra corresponding to the spinor singleton. In even dimensions one finds infinitely many deformations of the higher spin algebra labelled by the eigenvalues of Casimir operator of the little group SO(d−2 for massless representations.
Dreams, Perception, and Creative Realization.
Glaskin, Katie
2015-10-01
This article draws on the ethnography of Aboriginal Australia to argue that perceptual openness, extending from waking life into dreaming experience, provides an important cognitive framework for the apprehension of dreamt experience in these contexts. I argue that this perceptual openness is analogous to the "openness to experience" described as a personality trait that had been linked with dream recall frequency (among other things). An implication of identifying perceptual openness at a cultural rather than at an individual level is two-fold. It provides an example of the ways in which cultural differences affect perception, indicative of cognitive diversity; and, given the relationship between dreams and creativity suggested anecdotally and through research, a cultural orientation toward perceptual openness is also likely to have implications for the realization of creativity that occurs through dreams. Such creativity though cannot be separated from the relational context in which such dreamt material is elaborated and understood. Copyright © 2015 Cognitive Science Society, Inc.
Realization of fiber optic displacement sensors
Guzowski, Bartlomiej; Lakomski, Mateusz
2018-03-01
Fiber optic sensors are very promising because of their inherent advantages such as very small size, hard environment tolerance and impact of electromagnetic fields. In this paper three different types of Intensity Fiber Optic Displacement Sensors (I-FODS) are presented. Three configurations of I-FODS were realized in two varieties. In the first one, the cleaved multimode optical fibers (MMF) were used to collect reflected light, while in the second variety the MMF ended with ball lenses were chosen. To ensure an accurate alignment of optical fibers in the sensor head the MTP C9730 optical fiber ferrules were used. In this paper the influence of distribution of transmitting and detecting optical fibers on sensitivity and linear range of operation of developed I-FODS were investigated. We have shown, that I-FODS with ball lenses receive average 10.5% more reflected power in comparison to the cleaved optical fibers and they increase linearity range of I-FODS by 33%. In this paper, an analysis of each type of the realized sensor and detailed discussion are given.
String theory realizations of the nilpotent goldstino
Energy Technology Data Exchange (ETDEWEB)
Kallosh, Renata [Department of Physics and SITP, Stanford University, Stanford, CA 94305 (United States); Quevedo, Fernando [ICTP, Strada Costiera 11, 34151 Trieste (Italy); DAMTP, CMS, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom); Uranga, Angel M. [Instituto de Física Teórica UAM-CSIC, c/ Nicolás Cabrera 13-15, 28049 Madrid (Spain)
2015-12-09
We describe in detail how the spectrum of a single anti-D3-brane in four-dimensional orientifolded IIB string models reproduces precisely the field content of a nilpotent chiral superfield with the only physical component corresponding to the fermionic goldstino. In particular we explicitly consider a single anti-D3-brane on top of an O3-plane in warped throats, induced by (2,1) fluxes. More general systems including several anti-branes and other orientifold planes are also discussed. This provides further evidence to the claim that non-linearly realized supersymmetry due to the presence of antibranes in string theory can be described by supersymmetric theories including nilpotent superfields. Implications to the KKLT and related scenarios of de Sitter moduli stabilization, to cosmology and to the structure of soft SUSY-breaking terms are briefly discussed.
String theory realizations of the nilpotent goldstino
Kallosh, Renata; Quevedo, Fernando; Uranga, Angel M.
2015-12-01
We describe in detail how the spectrum of a single anti-D3-brane in four-dimensional orientifolded IIB string models reproduces precisely the field content of a nilpotent chiral superfield with the only physical component corresponding to the fermionic goldstino. In particular we explicitly consider a single anti-D3-brane on top of an O3-plane in warped throats, induced by (2, 1) fluxes. More general systems including several anti-branes and other orientifold planes are also discussed. This provides further evidence to the claim that non-linearly realized supersymmetry due to the presence of antibranes in string theory can be described by supersymmetric theories including nilpotent superfields. Implications to the KKLT and related scenarios of de Sitter moduli stabilization, to cosmology and to the structure of soft SUSY-breaking terms are briefly discussed.
Realization of an integral using anticommuting variables
International Nuclear Information System (INIS)
Valuev, B.N.
1979-01-01
It is shown that the integral defined by Berezin over anticommuting variables may be realized as a trace on the Clifford algebra. In fact, this realization makes precise the definition of the integral
Twistors and four-dimensional conformal field theory
International Nuclear Information System (INIS)
Singer, M.A.
1990-01-01
This is a report (with technical details omitted) on work concerned with generalizations to four dimensions of two-dimensional Conformed Field Theory. Accounts of this and related material are contained elsewhere. The Hilbert space of the four-dimensional theory has a natural interpretation in terms of massless spinor fields on real Minkowski space. From the twistor point of view this follows from the boundary CR-manifold P being precisely the space of light rays in real compactified Minkowski space. All the amplitudes can therefore be regarded as defined on Hilbert spaces built from Lorentzian spinor fields. Thus the twistor picture provides a kind of halfway house between the Lorentzian and Euclidean field theories. (author)
Worldsheet Realization of the Refined Topological String
Antoniadis, I; Hohenegger, S; Narain, K S; Assi, A Zein
2013-01-01
A worldsheet realization of the refined topological string is proposed in terms of physical string amplitudes that compute generalized N=2 F-terms of the form F_{g,n} W^{2g}Y^{2n} in the effective supergravity action. These terms involve the chiral Weyl superfield W and a superfield Y defined as an N=2 chiral projection of a particular anti-chiral T-bar vector multiplet. In Heterotic and Type I theories, obtained upon compactification on the six-dimensional manifold K3xT2, T is the usual K\\"ahler modulus of the T2 torus. These amplitudes are computed exactly at the one-loop level in string theory. They are shown to reproduce the correct perturbative part of the Nekrasov partition function in the field theory limit when expanded around an SU(2) enhancement point of the string moduli space. The two deformation parameters epsilon_- and epsilon_+ of the Omega-supergravity background are then identified with the constant field-strength backgrounds for the anti-self-dual graviphoton and self-dual gauge field of the...
A Direct Road to Majorana Fields
Directory of Open Access Journals (Sweden)
Andreas Aste
2010-10-01
Full Text Available A concise discussion of spin-1/2 field equations with a special focus on Majorana spinors is presented. The Majorana formalism which describes massive neutral fermions by the help of two-component or four-component spinors is of fundamental importance for the understanding of mathematical aspects of supersymmetric and other extensions of the Standard Model of particle physics, which may play an increasingly important role at the beginning of the LHC era. The interplay between the two-component and the four-component formalism is highlighted in an introductory way. Majorana particles are predicted both by grand unified theories, in which these particles are neutrinos, and by supersymmetric theories, in which they are photinos, gluinos and other states.
Primitive recursive realizability and basic propositional logic
Plisko, Valery
2007-01-01
Two notions of primitive recursive realizability for arithmetic sentences are considered. The first one is strictly primitive recursive realizability introduced by Z. Damnjanovic in 1994. We prove that intuitionistic predicate logic is not sound with this kind of realizability. Namely there
Supporting networks for realizing rights
DEFF Research Database (Denmark)
Wilson, Fiona
2005-01-01
The chapter explores how DFID, the British bi-lateral aid donor, adopted an innovative rights' based approach that rested on supporting in existing networks in Peru. Focus is put on the history and challenges of DFID's engagement with three networks in particular: in the fields of health, local...
Pair creation in inhomogeneous fields from worldline instantons
International Nuclear Information System (INIS)
Dunne, Gerald V.; Schubert, Christian
2006-01-01
We show how to do semiclassical nonperturbative computations within the worldline approach to quantum field theory using ''worldline instantons''. These worldline instantons are classical solutions to the Euclidean worldline loop equations of motion, and are closed spacetime loops parametrized by the proper-time. Specifically, we compute the imaginary part of the one loop effective action in scalar and spinor QED using worldline instantons, for a wide class of inhomogeneous electric field backgrounds
Classical realizability in the CPS target language
DEFF Research Database (Denmark)
Frey, Jonas
2016-01-01
Motivated by considerations about Krivine's classical realizability, we introduce a term calculus for an intuitionistic logic with record types, which we call the CPS target language. We give a reformulation of the constructions of classical realizability in this language, using the categorical...... techniques of realizability triposes and toposes. We argue that the presentation of classical realizability in the CPS target language simplifies calculations in realizability toposes, in particular it admits a nice presentation of conjunction as intersection type which is inspired by Girard's ludics....
Digital, realizable Wiener filtering in two-dimensions
International Nuclear Information System (INIS)
Ekstrom, M.P.
1979-01-01
The extension of Wiener's classical mean-square filtering theory to the estimation of two-dimensional (2-D), discrete random fields is discussed. In analogy with the 1-D case, the optimal realizable filter is derived by solution of a 2-D discrete Wiener--Hopf equation using a spectral factorization procedure. Computational algorithms for performing the required calculations are discussed. 3 figures
Symmetry realization of texture zeros
International Nuclear Information System (INIS)
Grimus, W.; Joshipura, A.S.; Lavoura, L.; Tanimoto, M.
2004-01-01
We show that it is possible to enforce texture zeros in arbitrary entries of the fermion mass matrices by means of Abelian symmetries; in this way, many popular mass-matrix textures find a symmetry justification. We propose two alternative methods which allow one to place zeros in any number of elements of the mass matrices that one wants. They are applicable simultaneously in the quark and lepton sectors. They are also applicable in grand unified theories. The number of scalar fields required by our methods may be large; still, in many interesting cases this number can be reduced considerably. The larger the desired number of texture zeros is, the simpler are the models which reproduce the texture. (orig.)
Realization of structural maps drawing algorithm for petroleum deposits
International Nuclear Information System (INIS)
Begendikov, A.Zh.; Esekeev, K.B.; Kakimzhanov, E.P.; Shaporenko, D.A.
1997-01-01
One of algorithms for realization of map drawing with help of computer is considered in the paper. Essence of problem consists in recovering of field by selective measuring in few points and graphical image of iso-lines of this field. In the problem an error value has being admitted up 30 % from square limited by iso-line. Initial data of problem have been set of points with arbitrary coordinates in which field value is given. Algorithm is founded on programming of two-dimension function calculation, recovering value of field by means interpolation
Realization of an optimized 3D USCT
Ruiter, Nicole V.; Göbel, Georg; Berger, Lutz; Zapf, Michael; Gemmeke, Hartmut
2011-03-01
A promising candidate for improved imaging of breast cancer is ultrasound computer tomography (USCT). Current experimental USCT systems are still focused in elevation dimension resulting in a large slice thickness, limited depth of field, loss of out-of-plane reflections, and a large number of movement steps to acquire a stack of images. 3DUSCT emitting and receiving spherical wave fronts overcomes these limitations. We built an optimized 3DUSCT with nearly isotropic 3D point spread function, realizing for the first time the full benefits of a 3D system. The 3DUSCT II is based on a semi-ellipsoidal transducer holder cut from polyoxymethylene. The aperture is implemented together with water supply, disinfection unit, temperature control, and movement mechanics in a patient bed. 2041 transducers are mounted in the aperture holder grouped into transducer array systems with embedded amplifiers and emitter electronics. The data acquisition is carried out with 480 parallel channels at 20MHz and with 12 bit resolution. 3.5 million A-Scans with 20 GByte of raw data are acquired for one breast volume. With data acquisition time of less than two minutes for one breast volume, the new system enables the next step of our research: a first clinical study.
Electronic circuit realization of the logistic map
Indian Academy of Sciences (India)
Abstract. An electronic circuit realization of the logistic difference equation is presented using analog electronics. The behaviour of the realized system is evalu- ated against computer simulations of the same. The circuit is found to exhibit the entire range of dynamics of the logistic equation: fixed points, periodicity, period.
Electronic circuit realization of the logistic map
Indian Academy of Sciences (India)
An electronic circuit realization of the logistic difference equation is presented using analog electronics. The behaviour of the realized system is evaluated against ... Author Affiliations. Madhekar Suneel1. PGAD (DRDO, Ministry of Defence, Government of India), DRDL Complex, Kanchanbagh, Hyderabad 500 058, India ...
Temperamental Prerequisites of Personality Self-Realization
Directory of Open Access Journals (Sweden)
S I Kudinov
2015-12-01
Full Text Available The article discusses the problem of individual and typological conditionality of personality self-realization. The results of an empirical research are submitted, the typological features of temperament properties with the variables of self-realization in teachers are compared.
Hausberg, Maria Christina; Schulz, Holger; Andreas, Sylke
2013-01-01
There has been a recent effort to investigate the role of individual resources in the field of mental health, but systematic research on this topic is lacking. The overall aim of the present study was the exploration of resource realization and other related variables in patients with mental disorders to provide basic knowledge on the upcoming field of psychotherapy research, which focuses on patients' strengths. Current resource realization was assessed with a shortened form of the Resource Realization Questionnaire in a sample of 332 inpatients with mental disorders. To explore the association between resource realization and related variables, group differences (t tests, analyses of variance) in gender, age, marital status, educational level, and type and number of diagnoses were calculated. The relationships between resource realization, symptom severity, interpersonal behavior, and therapeutic alliance were examined, and a regression tree analysis was calculated to establish relevant predictors of resource realization. There are several significant differences in current resource realization regarding marital status and number and type of diagnoses. A significant relationship between resource realization and symptom severity was found. The results regarding interpersonal behavior and therapeutic alliance were more heterogeneous. Symptom severity, gender, and chronic depression were found to be relevant predictors of resource realization. The close association between resource realization and symptom severity supports further investigation of the construct of resource realization within psychotherapy research. © 2012 Wiley Periodicals, Inc.
Classical field theory with fermions
International Nuclear Information System (INIS)
Borsanyi, Sz.; Hindmarsh, M.
2009-01-01
Classical field theory simulations have been essential for our understanding of non-equilibrium phenomena in particle physics. In this talk we discuss the possible extension of the bosonic classical field theory simulations to include fermions. In principle we use the inhomogeneous mean field approximation as introduced by Aarts and Smit. But in practice we turn from their deterministic technique to a stochastic approach. We represent the fermion field as an ensemble of pairs of spinor fields, dubbed male and female. These c-number fields solve the classical Dirac equation. Our improved algorithm enables the extension of the originally 1+1 dimensional analyses and is suitable for large-scale inhomogeneous settings, like defect networks.
Realized Volatility in Seoul Foreign Exchange Market
Directory of Open Access Journals (Sweden)
Chae-Shick Chung
2003-12-01
Full Text Available This paper constructs model-free estimates of daily KRW/USD's volatility, termed realized volatility, using two minutes frequency and compares the volatility with two major currencies of JPY/USD and EURO/USD. We confirm that the empirical properties of KRW/USD's realized volatility are very similar to early findings major currencies as argued by Andersen et. al(2003. Noteworthy results include the distribution of realized volatility are leptokurtic, but the distributions of logarithmic standard deviations are nearly Gaussian. We also find that the correlation between KRW/USD and major currency, JPY/USD and EURO/USD, are positive and increase with volatility.
True reference nanosensor realized with silicon nanowires.
Tarasov, A; Wipf, M; Bedner, K; Kurz, J; Fu, W; Guzenko, V A; Knopfmacher, O; Stoop, R L; Calame, M; Schönenberger, C
2012-06-26
Conventional gate oxide layers (e.g., SiO(2), Al(2)O(3), or HfO(2)) in silicon field-effect transistors (FETs) provide highly active surfaces, which can be exploited for electronic pH sensing. Recently, great progress has been achieved in pH sensing using compact integrateable nanowire FETs. However, it has turned out to be much harder to realize a true reference electrode, which--while sensing the electrostatic potential--does not respond to the proton concentration. In this work, we demonstrate a highly effective reference sensor, a so-called reference FET, whose proton sensitivity is suppressed by as much as 2 orders of magnitude. To do so, the Al(2)O(3) surface of a nanowire FET was passivated with a self-assembled monolayer of silanes with a long alkyl chain. We have found that a full passivation can be achieved only after an extended period of self-assembling lasting several days at 80 °C. We use this slow process to measure the number of active proton binding sites as a function of time by a quantitative comparison of the measured nonlinear pH-sensitivities to a theoretical model (site-binding model). Furthermore, we have found that a partially passivated surface can sense small changes in the number of active binding sites reaching a detection limit of δN(s) ≈ 170 μm(-2) Hz(-1/2) at 10 Hz and pH 3.
Modelling and Forecasting Multivariate Realized Volatility
DEFF Research Database (Denmark)
Halbleib, Roxana; Voev, Valeri
2011-01-01
This paper proposes a methodology for dynamic modelling and forecasting of realized covariance matrices based on fractionally integrated processes. The approach allows for flexible dependence patterns and automatically guarantees positive definiteness of the forecast. We provide an empirical appl...
Hamiltonian Realizations of Nonlinear Adjoint Operators
Fujimoto, Kenji; Scherpen, Jacquelien M.A.; Gray, W. Steven
2000-01-01
This paper addresses state-space realizations for nonlinear adjoint operators. In particular the relationship among nonlinear Hilbert adjoint operators, Hamiltonian extensions and port-controlled Hamiltonian systems are clarified. The characterization of controllability, observability and Hankel
Researchers Realize Major Breakthrough in Understanding Endometriosis
... 16, 2014 Researchers Realize Major Breakthrough in Understanding Endometriosis For a disease that affects an estimated 6 ... 10% of women, surprisingly little is known about endometriosis — a disorder that causes uterine tissue to grow ...
Some experiences with the Eigensystem Realization Algorithm
Pappa, Richard S.; Juang, Jer-Nan
1988-01-01
The Eigensystem Realization Algorithm (ERA) is a multiinput/multioutput time-domain algorithm for minimum-order system realization and modal parameter identification. It has been used for structural dynamics data analysis at the Langley Research Center for several years. Some of the practical experiences encountered in these projects are discussed in this paper. Three examples are used: the Galileo spacecraft, the Solar Array Flight Experiment, and a laboratory space-truss model. Several techniques for assessing identification accuracy are illustrated.
Realization of FRC interior and exterior furniture
Šonka, Š.; Frantová, M.; Štemberk, P.; Havrda, J.; Janouch, P.
2017-09-01
This article deals with the implementation of fibre reinforced concrete for interior and exterior furniture. The use of fibre reinforced concrete for non-traditional and small structures brings some specifics in design and realization. These are, in particular, the design of a suitable mixture, the choice of the shape of the structure in relation to the technological possibilities of realization, the static effects and finally the actual production of the element.
A Realization Approach for Residual Expressions
DEFF Research Database (Denmark)
Skovmose Kallesøe, Carsten; Izadi-Zamanabadi, Roozbeh; Wisniewski, Rafal
2006-01-01
This paper is concerned with state space realization of inherent redundant information in subsystems, which are identified by structural analysis (SA) approach. The identified subsystems are assumed to involve algebraic variables, representing unknown signals. The proposed realization method is b...... is based on a state space transformation, with which the unknown signals are decoupled. For the illustration purposes the method is applied on the model of a small satellite....
The linguistic realization of information packaging
Vallduví, Enric; Engdahl, Elisabet
1996-01-01
There is increasing awareness of the large degree of crosslinguistic diversity involved in the structural realization of information packaging (or information structure). Whereas English and many Germanic languages primarily exploit intonation for informational purposes, in other languages, like Catalan, syntax plays the primary role in the realization of information packaging and intonation is reduced to a secondary role. In yet another group of languages the primary structural correlate is ...
System Realization of Broad Band Digital Beam Forming for Digital Array Radar
Directory of Open Access Journals (Sweden)
Wang Feng
2013-09-01
Full Text Available Broad band Digital Beam Forming (DBF is the key technique for the realization of Digital Array Radar (DAR. We propose the method of combination realization of the channel equalization and DBF time delay filter function by using adaptive Sample Matrix Inversion algorithm. The broad band DBF function is realized on a new DBF module based on parallel fiber optic engines and Field Program Gate Array (FPGA. Good performance is achieved when it is used to some radar products.
A five dimensional unification of the vierbein and electromagnetic fields
International Nuclear Information System (INIS)
Kawai, Toshiharu
1982-01-01
A Kaluza-Klein type unification of the vierbein and electromagnetic fields is developed on the basis of the principal fiber bundle over the four dimensional space-time with the group U(1). A parameter γ which is directly related to the ''length'' of the fifth dimensional side of the bundle space is introduced. A spinor field PHI on the bundle space is introduced, and a pullback psi of PHI by a cross section to the base space is identified with the Dirac field. A spinor field PSI (not equal PHI) on the bundle space is defined from PHI, and its five dimensional Lagrangian density which leads to the Dirac equation for psi is given. The vierbein fields and electromagnetic vector potential are unified into the ''funfbein'' fields on the bundle space. The most general Lagrangian density of the funfbein fields, which is a function of these fields and of their first derivatives and is quadratic in the derivatives, is given. It has four parameters in addition to γ and is reduced to a linear sum of the Lagrangian densities of the vierbein fields and of the electromagnetic fields. Restrictions on the parameters imposed by experimental data and by a physical requirement are given. We discuss also a Lagrangian density which is reducible to the Einstein-Maxwell Lagrangian density. We can safely say that the bundle space is a five dimensional Lorentzian manifold and that the length of its fifth dimensional side is of the order of the Planck length or less. Any Dirac field defined as a pullback of the spinor field on the bundle space is expected to have an electric dipole moment with the magnitude h/2πc√x/8, if the gravitational and electromagnetic fields are described by the Einstein-Maxwell theory. (author)
Dynamical creation of complex vector solitons in spinor Bose-Einstein condensates
International Nuclear Information System (INIS)
Xiong Bo; Gong Jiangbin
2010-01-01
By numerical simulations of the Gross-Pitaevskii mean-field equations, we show that the dynamical creation of stable complex vector solitons in a homogeneous spin-1 Bose-Einstein condensate can be achieved by applying a localized magnetic field for a certain duration, with the initial uniform density prepared differently for the formation of different vector solitons. In particular, it is shown that stable dark-bright-dark vector solitons, dark-bright-bright vector solitons, and other analogous solutions can be dynamically created. It is also found that the peak intensity and the group velocity of the vector solitons thus generated can be tuned by adjusting the applied magnetic field. Extensions of our approach also allow for the creation of vector-soliton chains or the pumping of many vector solitons. The results can be useful for possible vector-soliton-based applications of dilute Bose-Einstein condensates.
4 pi-Periodicity of the spinor wave function under space rotation
Fischer, P; Jacobson, D L; Arif, M; Mezei, F
2000-01-01
We report the results of an experiment which observed the 4 pi-symmetry of the neutron wave function under space rotation by the use of a slowly rotating magnetic field which trapped the precessing neutron spin and turned it in space.
Invariant renormalization method for nonlinear realizations of dynamical symmetries
International Nuclear Information System (INIS)
Kazakov, D.I.; Pervushin, V.N.; Pushkin, S.V.
1977-01-01
The structure of ultraviolet divergences is investigated for the field theoretical models with nonlinear realization of the arbitrary semisimple Lie group, with spontaneously broken symmetry of vacuum. An invariant formulation of the background field method of renormalization is proposed which gives the manifest invariant counterterms off mass shell. A simple algorithm for construction of counterterms is developed. It is based on invariants of the group of dynamical symmetry in terms of the Cartan forms. The results of one-loop and two-loop calculations are reported
Energy Technology Data Exchange (ETDEWEB)
Delgado Acosta, E.G.; Banda Guzman, V.M.; Kirchbach, M. [UASLP, Instituto de Fisica, San Luis Potosi (Mexico)
2015-03-01
We propose a general method for the description of arbitrary single spin-j states transforming according to (j, 0) + (0, j) carrier spaces of the Lorentz algebra in terms of Lorentz tensors for bosons, and tensor-spinors for fermions, and by means of second-order Lagrangians. The method allows to avoid the cumbersome matrix calculus and higher ∂{sup 2j} order wave equations inherent to the Weinberg-Joos approach. We start with reducible Lorentz tensor (tensor-spinor) representation spaces hosting one sole (j, 0) + (0, j) irreducible sector and design there a representation reduction algorithm based on one of the Casimir invariants of the Lorentz algebra. This algorithm allows us to separate neatly the pure spin-j sector of interest from the rest, while preserving the separate Lorentz and Dirac indexes. However, the Lorentz invariants are momentum independent and do not provide wave equations. Genuine wave equations are obtained by conditioning the Lorentz tensors under consideration to satisfy the Klein-Gordon equation. In so doing, one always ends up with wave equations and associated Lagrangians that are of second order in the momenta. Specifically, a spin-3/2 particle transforming as (3/2, 0) + (0, 3/2) is comfortably described by a second-order Lagrangian in the basis of the totally anti-symmetric Lorentz tensor-spinor of second rank, Ψ {sub [μν]}. Moreover, the particle is shown to propagate causally within an electromagnetic background. In our study of (3/2, 0) + (0, 3/2) as part of Ψ {sub [μν]} we reproduce the electromagnetic multipole moments known from the Weinberg-Joos theory. We also find a Compton differential cross-section that satisfies unitarity in forward direction. The suggested tensor calculus presents itself very computer friendly with respect to the symbolic software FeynCalc. (orig.)
A Langevin Approach to a Classical Brownian Oscillator in an Electromagnetic Field
International Nuclear Information System (INIS)
Espinoza Ortiz, J. S.; Bauke, F. C.; Lagos, R. E.
2016-01-01
We consider a charged Brownian particle bounded by an harmonic potential, embedded in a Markovian heat bath and driven from equilibrium by external electric and magnetic fields. We develop a quaternionic-like (or Pauli spinor-like) representation, hitherto exploited in classical Lorentz related dynamics. Within this formalism, in a very straight forward and elegant fashion, we compute the exact solution for the resulting generalized Langevin equation, for the case of a constant magnetic field. For the case the source electromagnetic fields satisfy Maxwell's equations, yielding spinor-like Mathieu equations, we compute the solutions within the JWKB approximation. With the solutions at hand we further compute spatial, velocities and crossed time correlations. In particular we study the (kinetically defined) nonequilbrium temperature. Therefore, we can display the system's time evolution towards equilibrium or towards non equilibrium (steady or not) states. (paper)
A Langevin Approach to a Classical Brownian Oscillator in an Electromagnetic Field
Espinoza Ortiz, J. S.; Bauke, F. C.; Lagos, R. E.
2016-08-01
We consider a charged Brownian particle bounded by an harmonic potential, embedded in a Markovian heat bath and driven from equilibrium by external electric and magnetic fields. We develop a quaternionic-like (or Pauli spinor-like) representation, hitherto exploited in classical Lorentz related dynamics. Within this formalism, in a very straight forward and elegant fashion, we compute the exact solution for the resulting generalized Langevin equation, for the case of a constant magnetic field. For the case the source electromagnetic fields satisfy Maxwell's equations, yielding spinor-like Mathieu equations, we compute the solutions within the JWKB approximation. With the solutions at hand we further compute spatial, velocities and crossed time correlations. In particular we study the (kinetically defined) nonequilbrium temperature. Therefore, we can display the system's time evolution towards equilibrium or towards non equilibrium (steady or not) states.
Fifteen years of cold matter on the atom chip: promise, realizations, and prospects
Keil, Mark; Amit, Omer; Zhou, Shuyu; Groswasser, David; Japha, Yonathan; Folman, Ron
2016-01-01
Here we review the field of atom chips in the context of Bose–Einstein Condensates (BEC) as well as cold matter in general. Twenty years after the first realization of the BEC and 15 years after the realization of the atom chip, the latter has been found to enable extraordinary feats: from producing BECs at a rate of several per second, through the realization of matter-wave interferometry, and all the way to novel probing of surfaces and new forces. In addition, technological applications are also being intensively pursued. This review will describe these developments and more, including new ideas which have not yet been realized. PMID:27499585
High-speed DC transport of emergent monopoles in spinor photonic fluids.
Terças, H; Solnyshkov, D D; Malpuech, G
2014-07-18
We investigate the spin dynamics of half-solitons in quantum fluids of interacting photons (exciton polaritons). Half-solitons, which behave as emergent monopoles, can be accelerated by the presence of effective magnetic fields. We study the generation of dc magnetic currents in a gas of half-solitons. At low densities, the current is suppressed due to the dipolar oscillations. At moderate densities, a magnetic current is recovered as a consequence of the collisions between the carriers. We show a deviation from Ohm's law due to the competition between dipoles and monopoles.
Gravitational gauge fields and the cosmological constant
International Nuclear Information System (INIS)
Pagels, H.R.
1984-01-01
We describe field theories for which the action is completely independent of the metric and connection of the space-time manifold. The metric in our approach is no more a fundamental field than a hadron field is a fundamental field in QCD. The fundamental fields in the action are O(5) gauge fields and combinations of these fields are interpreted as the metric and connection so that conventional general relativity is obtained. Remarkably, all renormalizable matter actions for scalar, spinor, and Yang-Mills gauge fields can be made metric independent. Significantly, we find a new elementary invariance of the action which implies the cosmological constant must vanish. Finally, we discuss the quantum theory resulting from these ideas
Banach spaces that realize minimal fillings
Energy Technology Data Exchange (ETDEWEB)
Bednov, B. B.; Borodin, P. A., E-mail: noriiii@inbox.ru, E-mail: pborodin@inbox.ru [Faculty of Mechanics and Mathematics, Moscow State University (Russian Federation)
2014-04-30
It is proved that a real Banach space realizes minimal fillings for all its finite subsets (a shortest network spanning a fixed finite subset always exists and has the minimum possible length) if and only if it is a predual of L{sub 1}. The spaces L{sub 1} are characterized in terms of Steiner points (medians). Bibliography: 25 titles. (paper)
TECHNOLOGY EDUCATION: THE MEANS TO THE REALIZATION ...
African Journals Online (AJOL)
4. a land of bright and full opportunities, and. 5. a free and democratic society. The realization of the vision and the missions depend to a large extent on technology education. The minimum GNI per capital of the high income economies which Nigeria intends to join is at least USD 10,680 in the current rating. (Adebayo ...
Non-linear realizations and bosonic branes
International Nuclear Information System (INIS)
West, P.
2001-01-01
In this very short note, following hep-th/0001216, we express the well known bosonic brane as a non-linear realization. The reader may also consult hep-th/9912226, 0001216 and 0005270 where the branes of M theory are constructed as a non-linear realisation. The automorphisms of the supersymmetry algebra play an essential role. (author)
Evaluating realized genetic gains from tree improvement.
J.B. St. Clair
1993-01-01
Tree improvement has become an essential part of the management of forest lands for wood production, and predicting yields and realized gains from forests planted with genetically-improved trees will become increasingly important. This paper discusses concepts of tree improvement and genetic gain important to growth and yield modeling, and reviews previous studies of...
IMPEDIMENTS AGAINST THE REALIZATION OF FOOD SECURITY ...
African Journals Online (AJOL)
Is corruption of public officials responsible for food security policy problems in the state? •. Is the high rate ... food security fails. Uzoh, A. B. – Impediments Against The Realization of Food Security Policy in Imo State, Nigeria. .... power between men and women and between leaders are evident in agricultural credit scheme.
New Realization of Periodic Cycled Separation
DEFF Research Database (Denmark)
Toftegard, Bjarne; Clausen, Charlotte H.; Jørgensen, Sten B.
2016-01-01
A new realization of periodic cycled gas/liquid separation is presented. Separation factors and column efficiencies are compared for a column stripping ammonia from water with air, using three different sets of internals: conventional sieve trays, Sulzer BX gauze packings, and periodically cycled...... for columns with sieve trays....
The economic value of realized volatility
DEFF Research Database (Denmark)
Christoffersen, Peter; Feunou, Bruno; Jacobs, Kris
2014-01-01
Many studies have documented that daily realized volatility estimates based on intraday returns provide volatility forecasts that are superior to forecasts constructed from daily returns only. We investigate whether these forecasting improvements translate into economic value added. To do so, we ...
Measuring volatility with the realized range
M.P.E. Martens (Martin); D.J.C. van Dijk (Dick)
2006-01-01
textabstractRealized variance, being the summation of squared intra-day returns, has quickly gained popularity as a measure of daily volatility. Following Parkinson (1980) we replace each squared intra-day return by the high-low range for that period to create a novel and more efficient estimator
Twistors and supertwistors for exceptional field theory
Energy Technology Data Exchange (ETDEWEB)
Cederwall, Martin [Dept. of Fundamental Physics, Chalmers University of Technology, Gothenburg, SE 412 96 (Sweden)
2015-12-18
As a means of examining the section condition and its possible solutions and relaxations, we perform twistor transforms related to versions of exceptional field theory with Minkowski signature. The spinor parametrisation of the momenta naturally solves simultaneously both the mass-shell condition and the (weak) section condition. It is shown that the incidence relations for multi-particle twistors force them to share a common section, but not to be orthogonal. The supersymmetric extension contains additional scalar fermionic variables shown to be kappa-symmetry invariants. We speculate on some implications, among them a possible relation to higher spin theory.
Energy Technology Data Exchange (ETDEWEB)
Berkovits, Nathan [ICTP South American Institute for Fundamental Research,Instituto de Física Teórica, UNESP - Universidade Estadual Paulista,Rua Dr. Bento T. Ferraz 271, 01140-070, São Paulo, SP (Brazil)
2016-06-21
The pure spinor formalism for the superstring can be formulated as a twisted N=2 worldsheet theory with fermionic generators j{sub BRST} and composite b ghost. After untwisting the formalism to an N=1 worldsheet theory with fermionic stress tensor j{sub BRST}+b, the worldsheet variables combine into N=1 worldsheet superfields X{sup m} and Θ{sup α} together with a superfield constraint relating DX{sup m} and DΘ{sup α}. The constraint implies that the worldsheet superpartner of θ{sup α} is a bosonic twistor variable, and different solutions of the constraint give rise to the pure spinor or extended RNS formalisms, as well as a new twistor-string formalism with manifest N=1 worldsheet supersymmetry. These N=1 worldsheet methods generalize in curved Ramond-Ramond backgrounds, and a manifestly N=1 worldsheet supersymmetric action is proposed for the superstring in an AdS{sub 5}×S{sup 5} background in terms of the twistor superfields. This AdS{sub 5}×S{sup 5} worldsheet action is a remarkably simple fermionic coset model with manifest PSU(2,2|4) symmetry and might be useful for computing AdS{sub 5}×S{sup 5} superstring scattering amplitudes.
General Relativistic Mean Field Theory for rotating nuclei
Energy Technology Data Exchange (ETDEWEB)
Madokoro, Hideki [Kyushu Univ., Fukuoka (Japan). Dept. of Physics; Matsuzaki, Masayuki
1998-03-01
The {sigma}-{omega} model Lagrangian is generalized to an accelerated frame by using the technique of general relativity which is known as tetrad formalism. We apply this model to the description of rotating nuclei within the mean field approximation, which we call General Relativistic Mean Field Theory (GRMFT) for rotating nuclei. The resulting equations of motion coincide with those of Munich group whose formulation was not based on the general relativistic transformation property of the spinor fields. Some numerical results are shown for the yrast states of the Mg isotopes and the superdeformed rotational bands in the A {approx} 60 mass region. (author)
The nursing discipline and self-realization.
Kristoffersen, Margareth; Friberg, Febe
2015-09-01
It is obvious from literature within the nursing discipline that nursing is related to moral or moral-philosophical related ideas which are other-oriented. The socio-cultural process of change in modern society implies that more self-oriented ideas have been found to be significant. The overall aim of this article is to highlight self-oriented moral or moral-philosophical related ideas as an important part of the nursing discipline. This is achieved by (a) exploring self-realization as a significant self-oriented moral or moral-philosophical related idea based on a philosophical anthropological perspective, (b) demonstrating how moral or moral-philosophical related ideas are expressed by nurses, (c) discussing the relevance of self-realization for the nursing discipline, and (d) pointing out possible consequences for the future development of the discipline of nursing. This theoretical study draws empirical examples from interviews. Data consisted of interviews with 13 nurses with varying work experience within the primary and secondary somatic and psychiatric health service, from inside as well as outside institutions. The empirical study was approved by the Norwegian Social Science Data Services. Information was given and consent was obtained from the study participants. Findings are presented in two themes: (a) other-oriented ideas and (b) self-oriented ideas. More concretely, the findings show that nurses hope to make life as good as possible for the patient and they have a wish to improve themselves as human beings, to become better persons. The relevance of self-realization for the nursing discipline is discussed along two lines, first, by connecting nurses' self-understanding to a horizon of identity and second, by considering what self-realization could offer. It is of ultimate concern for the nursing discipline to highlight self-realization connected to the positive view of freedom understood as an exercise-concept. Further identifying and articulating the
Exploring heterogeneous market hypothesis using realized volatility
Chin, Wen Cheong; Isa, Zaidi; Mohd Nor, Abu Hassan Shaari
2013-04-01
This study investigates the heterogeneous market hypothesis using high frequency data. The cascaded heterogeneous trading activities with different time durations are modelled by the heterogeneous autoregressive framework. The empirical study indicated the presence of long memory behaviour and predictability elements in the financial time series which supported heterogeneous market hypothesis. Besides the common sum-of-square intraday realized volatility, we also advocated two power variation realized volatilities in forecast evaluation and risk measurement in order to overcome the possible abrupt jumps during the credit crisis. Finally, the empirical results are used in determining the market risk using the value-at-risk approach. The findings of this study have implications for informationally market efficiency analysis, portfolio strategies and risk managements.
Realizing Mobile Web Services for Dynamic Applications
Zaplata, Sonja; Dreiling, Viktor; Lamersdorf, Winfried
Use of web services also on mobile devices becomes increasingly relevant. However, realizing such mobile web services based on the standard protocol stack is often inappropriate for resource-restricted mobile devices in dynamic networks. On the other hand, using specialized alternative protocols restricts compatibility with traditional service applications. Thus, existing approaches often do not allow to integrate heterogeneous service instances dynamically, as it is, e.g., required for executing mobile service-based business processes.
Realization of Thermal Inertia in Frequency Domain
Hong, Boe-Shong; Chou, Chia-Yu
2014-01-01
To realize the lagging behavior in heat conduction observed in these two decades, this paper firstly theoretically excludes the possibility that the underlying thermal inertia is a result of the time delay in heat diffusion. Instead, we verify in experiments the electro-thermal analogy, wherein the thermal inertial is parameterized by thermal inductance that formulates hyperbolic heat-conduction. The thermal hyperbolicity exhibits a special frequency response in Bode plot, wherein the amplitu...
Experimental functional realization of attribute grammar system
Directory of Open Access Journals (Sweden)
I. Attali
2002-07-01
Full Text Available In this paper we present an experimental functional realization of attribute grammar(AG system for personal computers. For AG system functioning only Turbo Prolog compiler is required. The system functioning is based on a specially elaborated metalanguage for AG description, universal syntactic and semantic constructors. The AG system provides automatic generation of target compiler (syntax--oriented software using Turbo Prolog as object language.
Realization of superconductive films by screen printing
International Nuclear Information System (INIS)
Baudry, H.
1988-01-01
Screen printing is a promising method to manufacture superconductive lines making use of superconductive ceramics. An ink has been realized with YBa 2 Cu 3 0 7-x' and the process conditions defined by thermal analysis. A superconductive transition is observed after screen printing on MgO. The firing of the layer is made at 920 0 C followed by a reoxidation step at 420 0 C. The silver electrical contacts are also screen printed [fr
Mathematical aspects of quantum field theory
de Faria, Edson
2010-01-01
Over the last century quantum field theory has made a significant impact on the formulation and solution of mathematical problems and inspired powerful advances in pure mathematics. However, most accounts are written by physicists, and mathematicians struggle to find clear definitions and statements of the concepts involved. This graduate-level introduction presents the basic ideas and tools from quantum field theory to a mathematical audience. Topics include classical and quantum mechanics, classical field theory, quantization of classical fields, perturbative quantum field theory, renormalization, and the standard model. The material is also accessible to physicists seeking a better understanding of the mathematical background, providing the necessary tools from differential geometry on such topics as connections and gauge fields, vector and spinor bundles, symmetries and group representations.
An inductorless CMOS realization of Chua's circuit
Radwan, A G; El-Sedeek, A L
2003-01-01
In this paper, an inductorless CMOS realization of Chua's circuit [IEEE Trans. Circ. Syst.--I 1985;32:798] is presented. The circuit is derived from the dimensionless form of Chua's circuit and can generate Rossler or double-scroll attractors by changing a single capacitor's value. Variables are represented in the current domain to facilitate adding or subtracting variables. New G sub m -C representation of the Chua diode as well as the Chua circuit are presented. The circuit can operate from supply voltage as low as +-1.5 V. Transistor-level simulation results using PSpice in 0.5 mu m Mietec process are presented.
Realized Variance and Market Microstructure Noise
DEFF Research Database (Denmark)
Hansen, Peter R.; Lunde, Asger
2006-01-01
-based estimator dominates the RV for the estimation of integrated variance (IV). An empirical analysis of the Dow Jones Industrial Average stocks reveals that market microstructure noise its time-dependent and correlated with increments in the efficient price. This has important implications for volatility......We study market microstructure noise in high-frequency data and analyze its implications for the realized variance (RV) under a general specification for the noise. We show that kernel-based estimators can unearth important characteristics of market microstructure noise and that a simple kernel...
FPGA Realization of Memory 10 Viterbi Decoder
DEFF Research Database (Denmark)
Paaske, Erik; Bach, Thomas Bo; Andersen, Jakob Dahl
1997-01-01
A feasibility study for a low cost, iterative, serially concatenated coding system is performed. The system uses outer (255,223) Reed-Solomon codes and convolutional inner codes with memory 10 and rates 1/4 or 1/6. The corresponding inner decoder is a Viterbi decoder, which can operate in a forced...... sequence mode when feedback from the Reed-Solomon decoder is available. The Viterbi decoder is realized using two Altera FLEX 10K50 FPGA's. The overall operating speed is 30 kbit/s, and since up to three iterations are performed for each frame and only one decoder is used, the operating speed...
Developing communications requirements for Agile Product Realization
Energy Technology Data Exchange (ETDEWEB)
Forsythe, C.; Ashby, M.R.
1994-03-01
Sandia National Laboratories has undertaken the Agile Product Realization for Innovative electroMEchanical Devices (A-PRIMED) pilot project to develop and implement technologies for agile design and manufacturing of electrochemical components. Emphasis on information-driven processes, concurrent engineering and multi-functional team communications makes computer-supported cooperative work critical to achieving significantly faster product development cycles. This report describes analyses conducted in developing communications requirements and a communications plan that addresses the unique communications demands of an agile enterprise.
APM Best Practices Realizing Application Performance Management
Sydor, Michael J
2011-01-01
The objective of APM Best Practices: Realizing Application Performance Management is to establish reliable application performance management (APM) practices - to demonstrate value, to do it quickly, and to adapt to the client circumstances. It's important to balance long-term goals with short-term deliverables, but without compromising usefulness or correctness. The successful strategy is to establish a few reasonable goals, achieve them quickly, and then iterate over the same topics two more times, with each successive iteration expanding the skills and capabilities of the APM team. This str
Enablers & Barriers for Realizing Modularity Benefits
DEFF Research Database (Denmark)
Storbjerg, Simon Haahr; Brunø, Thomas Ditlev; Thyssen, Jesper
2012-01-01
far less attention compared to the theories and methods concerning modularization of technical systems. Harvesting the full potential of modularization, particularly in relation to product development agility, depends on more than an optimal architecture. Key enablers in this context...... are the organizational and systems related aspects. Recognizing the need for guidance to realize the benefits of modularity, the purpose of this study is through a literature study and a case study to improve the insight into the organizational and systems related enablers and barriers with regard to obtaining the full...
Matrix realization of string algebra axioms and conditions of invariance
International Nuclear Information System (INIS)
Babichev, L.F.; Kuvshinov, V.I.; Fedorov, F.I.
1990-01-01
The matrix representations of Witten's and B-algebras of the field string theory in finite dimensional space of the ghost states are suggested for the case of Virasoro algebra truncated to its SU(1,1) subalgebra. In this case all algebraic operations of Witten's and B-algebras are realized in explicit form as some matrix operations in the graded complex vector space. The structure of string action coincides with the universal non-linear cubic matrix form of action for the gauge field theories. These representations lead to matrix conditions of theory invariance which can be used for finding of the explicit form of corresponding operators of the string algebras. (author)
Lounesto, Pertti
1993-01-01
This volume contains a facsimile reproduction of Marcel Riesz's notes of a set of lectures he delivered at the University of Maryland, College Park, between October 1957 and January 1958, which has not been formally published to date This seminal material (arranged in four chapters), which contributed greatly to the start of modern research on Clifford algebras, is supplemented in this book by notes which Riesz dictated to E Folke Bolinder in the following year and which were intended to be a fifth chapter of the Riesz lecture notes In addition, Riesz's work on Clifford algebra is put into an historical perspective in a separate review by P Lounesto As well as providing an introduction to Clifford algebra, this volume will be of value to those interested in the history of mathematics
Regularizing cubic open Neveu-Schwarz string field theory
International Nuclear Information System (INIS)
Berkovits, Nathan; Siegel, Warren
2009-01-01
After introducing non-minimal variables, the midpoint insertion of Y Y-bar in cubic open Neveu-Schwarz string field theory can be replaced with an operator N ρ depending on a constant parameter ρ. As in cubic open superstring field theory using the pure spinor formalism, the operator N ρ is invertible and is equal to 1 up to a BRST-trivial quantity. So unlike the linearized equation of motion Y Y-bar QV = 0 which requires truncation of the Hilbert space in order to imply QV = 0, the linearized equation N ρ QV = 0 directly implies QV = 0.
Quantum processes in a strong electromagnetic field producing pairs. 3
International Nuclear Information System (INIS)
Gitman, D.M.; Gavrilov, S.P.
1977-01-01
The Furry picture in quantum electrodynamics with an external field producing real pairs has been generalized. For the required generalization to be achieved all operators of a spinor field are expressed through functions of production and annihilation operators and formulated are the rules for reduction to a generalized normal form, i.e., to such a form in which all the production operators in each term are on the left from all the annihilation operators. The diagram technique for matrix elements of random processes has been considered
Realization of quantum Fourier transform over ZN
International Nuclear Information System (INIS)
Fu Xiang-Qun; Bao Wan-Su; Li Fa-Da; Zhang Yu-Chao
2014-01-01
Since the difficulty in preparing the equal superposition state of amplitude is 1/√N, we construct a quantile transform of quantum Fourier transform (QFT) over Z N based on the elementary transforms, such as Hadamard transform and Pauli transform. The QFT over Z N can then be realized by the quantile transform, and used to further design its quantum circuit and analyze the requirements for the quantum register and quantum gates. However, the transform needs considerable quantum computational resources and it is difficult to construct a high-dimensional quantum register. Hence, we investigate the design of t-bit quantile transform, and introduce the definition of t-bit semiclassical QFT over Z N . According to probability amplitude, we prove that the transform can be used to realize QFT over Z N and further design its quantum circuit. For this transform, the requirements for the quantum register, the one-qubit gate, and two-qubit gate reduce obviously when compared with those for the QFT over Z N . (general)
Estimating quadratic variation using realized variance
DEFF Research Database (Denmark)
Barndorff-Nielsen, Ole Eiler; Shephard, N.
2002-01-01
This paper looks at some recent work on estimating quadratic variation using realized variance (RV) - that is, sums of M squared returns. This econometrics has been motivated by the advent of the common availability of high-frequency financial return data. When the underlying process is a semimar......This paper looks at some recent work on estimating quadratic variation using realized variance (RV) - that is, sums of M squared returns. This econometrics has been motivated by the advent of the common availability of high-frequency financial return data. When the underlying process...... is a semimartingale we recall the fundamental result that RV is a consistent (as M ) estimator of quadratic variation (QV). We express concern that without additional assumptions it seems difficult to give any measure of uncertainty of the RV in this context. The position dramatically changes when we work...... with a rather general SV model - which is a special case of the semimartingale model. Then QV is integrated variance and we can derive the asymptotic distribution of the RV and its rate of convergence. These results do not require us to specify a model for either the drift or volatility functions, although we...
Geometrization of the electromagnetic field and dark matter
International Nuclear Information System (INIS)
Pestov, I.B.
2005-01-01
A general concept of potential field is introduced. The potential field that one puts in correspondence with dark matter, has fundamental geometrical interpretation (parallel transport) and has intrinsically inherent local symmetry. The equations of dark matter field are derived that are invariant with respect to the local transformations. It is shown how to reduce these equations to the Maxwell equations. Thus, the dark matter field may be considered as generalized electromagnetic field and a simple solution of the old problem is given to connect electromagnetic field with geometrical properties of the physical manifold itself. It is shown that gauge fixing renders generalized electromagnetic field effectively massive while the Maxwell electromagnetic field remains massless. To learn more about interactions between matter and dark matter on the microscopical level (and to recognize the fundamental role of internal symmetry) the general covariant Dirac equation is derived in the Minkowski space-time which describes the interactions of spinor field with dark matter field
Realization and characterization of a stabilized power supply for a laser diode
International Nuclear Information System (INIS)
Houji, Imen
2010-01-01
This final project study is entitled realization and characterization of a stabilized power supply for a diode laser. It was developed at the National Center for Nuclear Sciences and Technology at Sidi Thabet. In a first step, we are interested on the physics of lasers and its applications in different fields. We have also focused on the electronic manufacturing of diode lasers. In a second part, we have presented in detail the current stabilized power supply and the detailed description of the various blocks of this electronic schema. Before the experimental realization, we simulated the electronic schema using the commercial software P roteus 7 . Finally we presented the practical realization of various cards.
Design and Realization of Universal Data Interface
Directory of Open Access Journals (Sweden)
Jong-Woo Kim
2005-03-01
Full Text Available KARI studied data interface of Space Applications for developing Space Experimental Instrument in International Space Station, designed, and manufactured the UDIS (International Sapce Station Universal Data Interface simulator according to requirements of the data interface. This paper explains the design and implementation of UDIS for space application. UDIS is the instrument which simulate to interface the data from ISS to experiment module, payload and habitation module and use the development of a experiment system in the space. This simulator will be used to the GSE (Ground Support Equipment for test of experiment system. By realization of the simulator, we ensure data interface skills for a manned-space data communication system.
Realization of Thermal Inertia in Frequency Domain
Directory of Open Access Journals (Sweden)
Boe-Shong Hong
2014-02-01
Full Text Available To realize the lagging behavior in heat conduction observed in these two decades, this paper firstly theoretically excludes the possibility that the underlying thermal inertia is a result of the time delay in heat diffusion. Instead, we verify in experiments the electro-thermal analogy, wherein the thermal inertial is parameterized by thermal inductance that formulates hyperbolic heat-conduction. The thermal hyperbolicity exhibits a special frequency response in Bode plot, wherein the amplitude ratios is kept flat after crossing some certain frequency, as opposed to Fourier heat-conduction. We apply this specialty to design an instrument that reliably identifies thermal inductances of some materials in frequency domain. The instrument is embedded with a DSP-based frequency synthesizer capable of modulating frequencies in utmost high-resolution. Thermal inertia implies a new possibility for energy storage in analogy to inductive energy storage in electricity or mechanics.
Effective Complexity of Stationary Process Realizations
Directory of Open Access Journals (Sweden)
Arleta Szkoła
2011-06-01
Full Text Available The concept of effective complexity of an object as the minimal description length of its regularities has been initiated by Gell-Mann and Lloyd. The regularities are modeled by means of ensembles, which is the probability distributions on finite binary strings. In our previous paper [1] we propose a definition of effective complexity in precise terms of algorithmic information theory. Here we investigate the effective complexity of binary strings generated by stationary, in general not computable, processes. We show that under not too strong conditions long typical process realizations are effectively simple. Our results become most transparent in the context of coarse effective complexity which is a modification of the original notion of effective complexity that needs less parameters in its definition. A similar modification of the related concept of sophistication has been suggested by Antunes and Fortnow.
Design and Realization of Intelligent Flow Controller
Directory of Open Access Journals (Sweden)
Jianxiong Ye
2014-09-01
Full Text Available According to accurate flow rate control requirements in large irrigation zone, a fuzzy controller with dead-band is designed on the characteristics analysis and comparison of PID and Fuzzy. The setting values of water flow for gates are determined by real-time water level detection sensors, and the realistic value of discharged water and gate opening are detected out with relative sensors, simulation manifest that the specific control strategy can adjust the gate swiftly in circumstance of huge offset, and regulate the gate slightly in time of small bias, it is realized with Siemens S315 PLC (Programmable Logical Controller and has being working steadily for 2 years, the aim of regulation is performed properly.
Social network analysis realization and exploitation
Davenport, Jack H.; Nolan, James J.
2015-05-01
Intelligence analysts demand rapid information fusion capabilities to develop and maintain accurate situational awareness and understanding of dynamic enemy threats in asymmetric military operations. The ability to extract meaning in relationships between people, objects, and locations from a variety of unstructured text datasets is critical to proactive decision making. Additionally, the ability to automatically cluster text documents about entities and discover connections between those documents allows the analyst to navigate an extremely large collection of documents. Analysts also demand a temporal understanding of the extracted relationships between entities and connections between documents. We describe approaches to automatically realize the social networks via concept extraction, relationship extraction, and document connection algorithms; we also describe approaches to exploit the network by visualizing the results to the analyst such that changes over time are evident.
Realization of the chess mate solver application
Directory of Open Access Journals (Sweden)
Vučković Vladan V.
2004-01-01
Full Text Available This paper presents details of the chess mate solver application, which is a part of the author’s Geniss general chess application. The problem chess is an important domain connected with solving of the chess problems. The Geniss Mate Solver (G.M.S. application solves Mate-in-N-move problems. Main techniques used for the implementation of the application are full-width searching with Alpha-Beta pruning technique and zero evaluation function. The application is written in Delphi for Windows programming environment and the searching engine is completely coded in assembly language (about 10000 lines. This hybrid software structure enables efficient program development by using high-level programming environment and the realization of a very fast searching engine at the same time. The machine code is manually coded and could achieve above 7 million generated positions per second on the 1Ghz Celeron PC.
Realization of mechanical rotation in superfluid helium
Gordon, E. B.; Kulish, M. I.; Karabulin, A. V.; Matyushenko, V. I.; Dyatlova, E. V.; Gordienko, A. S.; Stepanov, M. E.
2017-09-01
The possibility of using miniaturized low-power electric motors submerged in superfluid helium for organization of rotation inside a cryostat has been investigated. It has been revealed that many of commercial micromotors can operate in liquid helium consuming low power. Turret with 5 sample holders, assembled on the base of stepper motor, has been successfully tested in experiments on the nanowire production in quantized vortices of superfluid helium. Application of the stepper motor made it possible in a single experiment to study the effect of various experimental parameters on the yield and quality of the nanowires. The promises for continuous fast rotation of the bath filled by superfluid helium by using high-speed brushless micromotor were outlined and tested. Being realized, this approach will open new possibility to study the guest particles interaction with the array of parallel linear vortices in He II.
Master formulas for the dressed scalar propagator in a constant field
Ahmad, Aftab; Ahmadiniaz, Naser; Corradini, Olindo; Kim, Sang Pyo; Schubert, Christian
2017-06-01
The worldline formalism has previously been used for deriving compact master formulas for the one-loop N-photon amplitudes in both scalar and spinor QED, and in the vacuum as well as in a constant external field. For scalar QED, there is also an analogous master formula for the propagator dressed with N photons in the vacuum. Here, we extend this master formula to include a constant field. The two-photon case is worked out explicitly, yielding an integral representation for the Compton scattering cross section in the field suitable for numerical integration in the full range of electric and magnetic field strengths.
Master formulas for the dressed scalar propagator in a constant field
Energy Technology Data Exchange (ETDEWEB)
Ahmad, Aftab [Department of Physics, Gomal University, 29220 D.I. Khan, K.P.K (Pakistan); Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio C-3, Ciudad Universitaria, Morelia 58040, Michoacán (Mexico); Ahmadiniaz, Naser, E-mail: Ahmadiniaz@ibs.re.kr [Center for Relativistic Laser Science, Institute for Basic Science, Gwangju 61005 (Korea, Republic of); Department of Physics, Kunsan National University, Kunsan 54150 (Korea, Republic of); Corradini, Olindo [Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Università di Modena e Reggio Emilia, Via Campi 213/A, I-41125 Modena (Italy); INFN, Sezione di Bologna, Via Irnerio 46, I-40126 Bologna (Italy); Kim, Sang Pyo [Center for Relativistic Laser Science, Institute for Basic Science, Gwangju 61005 (Korea, Republic of); Department of Physics, Kunsan National University, Kunsan 54150 (Korea, Republic of); Schubert, Christian [Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio C-3, Ciudad Universitaria, Morelia 58040, Michoacán (Mexico)
2017-06-15
The worldline formalism has previously been used for deriving compact master formulas for the one-loop N-photon amplitudes in both scalar and spinor QED, and in the vacuum as well as in a constant external field. For scalar QED, there is also an analogous master formula for the propagator dressed with N photons in the vacuum. Here, we extend this master formula to include a constant field. The two-photon case is worked out explicitly, yielding an integral representation for the Compton scattering cross section in the field suitable for numerical integration in the full range of electric and magnetic field strengths.
Master formulas for the dressed scalar propagator in a constant field
Directory of Open Access Journals (Sweden)
Aftab Ahmad
2017-06-01
Full Text Available The worldline formalism has previously been used for deriving compact master formulas for the one-loop N-photon amplitudes in both scalar and spinor QED, and in the vacuum as well as in a constant external field. For scalar QED, there is also an analogous master formula for the propagator dressed with N photons in the vacuum. Here, we extend this master formula to include a constant field. The two-photon case is worked out explicitly, yielding an integral representation for the Compton scattering cross section in the field suitable for numerical integration in the full range of electric and magnetic field strengths.
Intercultural Education and the Realization of Intercultural Capital in Mexico
Directory of Open Access Journals (Sweden)
Andreas Pöllmann
2017-07-01
Full Text Available Contrary to what the seductive marketing power of neoliberal “free”-trade ideology and its more or less explicit postulation of homo interculturalis might suggest, the multi-dimensional realization of intercultural capital cannot simply be taken for granted, but needs to be subjected to critical empirically grounded scrutiny. Drawing on the findings of three recent research projects, the present article explores the prospects and limitations of intercultural capital realization in contemporary Mexico – at nearly two and a half decades of the country’s membership in the quintessentially neoliberal North Atlantic Free Trade Agreement (NAFTA and with a particular interest in the field of intercultural education. Whilst the article does not engage in evaluations of NAFTA, nor offer a contribution to the critique of neoliberal globalization and the mercantilization of formal education, it nonetheless raises important questions for all those interested in alternative forms of intercultural cooperation that convey a vision beyond narrowly instrumental business interests. As our three research examples forcefully illustrate, it is high time for a socioculturally sensitive educational development toward more intercultural literacy – both inside the multicultural national context and internationally.
Realized GARCH: A Complete Model of Returns and Realized Measures of Volatility
DEFF Research Database (Denmark)
Hansen, Peter Reinhard; Huang, Zhuo (Albert); Shek, Howard Howan
to latent volatility. This equation facilitates a simple modeling of the dependence between returns and future volatility that is commonly referred to as the leverage effect. An empirical application with DJIA stocks and an exchange traded index fund shows that a simple Realized GARCH structure leads...
On the physical realizability of quantum stochastic walks
Taketani, Bruno; Govia, Luke; Schuhmacher, Peter; Wilhelm, Frank
Quantum walks are a promising framework that can be used to both understand and implement quantum information processing tasks. The recently developed quantum stochastic walk combines the concepts of a quantum walk and a classical random walk through open system evolution of a quantum system, and have been shown to have applications in as far reaching fields as artificial intelligence. However, nature puts significant constraints on the kind of open system evolutions that can be realized in a physical experiment. In this work, we discuss the restrictions on the allowed open system evolution, and the physical assumptions underpinning them. We then introduce a way to circumvent some of these restrictions, and simulate a more general quantum stochastic walk on a quantum computer, using a technique we call quantum trajectories on a quantum computer. We finally describe a circuit QED approach to implement discrete time quantum stochastic walks.
Dynamical realizations of l-conformal Newton–Hooke group
International Nuclear Information System (INIS)
Galajinsky, Anton; Masterov, Ivan
2013-01-01
The method of nonlinear realizations and the technique previously developed in [A. Galajinsky, I. Masterov, Nucl. Phys. B 866 (2013) 212, (arXiv:1208.1403)] are used to construct a dynamical system without higher derivative terms, which holds invariant under the l-conformal Newton–Hooke group. A configuration space of the model involves coordinates, which parametrize a particle moving in d spatial dimensions and a conformal mode, which gives rise to an effective external field. The dynamical system describes a generalized multi-dimensional oscillator, which undergoes accelerated/decelerated motion in an ellipse in accord with evolution of the conformal mode. Higher derivative formulations are discussed as well. It is demonstrated that the multi-dimensional Pais–Uhlenbeck oscillator enjoys the l=3/2 -conformal Newton–Hooke symmetry for a particular choice of its frequencies
Realizing the promise of breast cancer vaccines
Directory of Open Access Journals (Sweden)
Jackson E
2012-08-01
Full Text Available Erica Jackson, Hatem SolimanUniversity of South Florida/Moffitt Cancer Center and Research Institute, Tampa, FL, USAAbstract: Breast cancer vaccines are being developed to stimulate adaptive antitumor immune responses in patients. These vaccines have the potential to treat breast cancer with minimal side effects and toxicity. However, many obstacles still need to be overcome to fully realize the vaccines' clinical benefit. A review of the literature was conducted to assess the use of vaccines in targeting transformed cells. Four vaccines currently under study were discussed, each summarizing the different vaccine platforms used to introduce target antigen to the patient's immune system. The advantages and disadvantages of each method were discussed, although no one method was found to be superior. Additional issues addressed included overcoming tumor-induced immunosuppression, immune evasion of transformed cells, the use of vaccines in combination therapy, and the challenges of using these vaccines in various clinical settings. Vaccines may be most effective in patients with minimal residual disease, as opposed to using them in the metastatic setting. Also, specific clinical trial design considerations for the use of vaccines in cancer patients, such as time-to-failure end points, were discussed. Understanding these various elements will be important to the translation of breast cancer vaccine therapy into routine clinical practice.Keywords: breast cancer, vaccine, immunotherapy, immune tolerance, peptide vaccine, dendritic cell vaccine
Realizing the potential of nuclear energy
International Nuclear Information System (INIS)
Walske, C.
1982-01-01
The future of nuclear power, just as the future of America, can be viewed with optimism. There is hope in America's record of overcoming obstacles, but growth is essential for that hope to be realized. Despite the downturn in energy demand made possible by conservation, we will need a 35% growth in total energy for new workers and production. Electricity generated by nuclear or coal can make US production more cost-competitive, and it can power mass-transit systems, electric heat pumps, and communications and information systems. Changes in electricity and gross national product (GNP) have been more closely in step since 1973 than have total energy and GNP. The nuclear power units now under construction will add 80,000 megawatts to the 56,000 now on line. It is important to note that, while utilities are cancelling plans for nuclear plants, they aren't ordering new coal plants, which shows the impact of the high cost of money. Interest rates must come down and public-relations efforts to sell electricity must improve to change the situation. Although capital shortages are real, waste disposal is a problem of perception that was politically induced because the government failed to provide a demonstration of safety as the French are doing. Streamlined regulatory and insurance procedures can help to justify optimism in the nuclear option. 4 figures
Next-generation LWRs development toward realization
International Nuclear Information System (INIS)
Mitsumata, Hiroki; Kasai, S.; Ohga, Y.; Kurosaki, T.
2010-01-01
This special article introduced the round-table talk of 'next-generation LWRs development toward realization' at the issue of an intermediate evaluation report about technology development of next-generation LWRs in 2010. 'Recent trends around nuclear energy and next-generation LWRs development' and 'summary of the report' were also included. After a 2-year feasibility study on development of next-generation LWRs, the vision of this development has been established as follows; the new designs of HP-BWR and HP-PWR, based on ABWR and APWR, are to lead to a large reduction in construction and generation costs and a 30% reduction of spent fuel quantity with improved safety, 30-month construction and a design life of 80 years with 24-month operating cycle. In 2008 the project was established within the Institute of Applied Energy to pursue this vision, involving three manufacturers. Over eight years, the project is to develop designs of BWR and PWR with 1700-1800 MWe. Basic designs are to be finished by 2015, with significant deployment as new alternative reactors in Japan or internationally by 2030. (T. Tanaka)
Dual realizations of dynamical symmetry breaking
International Nuclear Information System (INIS)
Dudas, Emilian; Papineau, Chloe
2006-01-01
We show the infrared equivalence between a recently proposed model containing a six dimensional scalar field with a four-dimensional localized Higgs type potential and the four-dimensional Nambu-Jona-Lasinio (NJL) model. In the dual NJL description, the fermions are localized at the origin of a large two-dimensional compact space. Due to a classical running effect above the compactification scale, the four-fermion coupling of the NJL model increases from the cutoff scale down to the compactification scale, providing the large Fermi coupling needed for the dynamical symmetry breaking. We also present a string theory embedding of our field-theory construction. On more general grounds, our results suggest that 4d models with dynamical symmetry breaking can be given a higher dimensional description in terms of field theories with nontrivial boundary conditions in the internal space
Realizing e-government benefits with minimal capabilities
DEFF Research Database (Denmark)
Pedersen, Keld
2017-01-01
Abstract Purpose — The purpose is to increase our understanding of the requirements for public sector organizations to implement benefits realization practices. The research compares benefits realization practices as suggested by the literature with actual practice with the goal of identifying bo...... the research studies benefits realization from an organizational process perspective, and not from the perspective of IT projects. Keywords — Benefits realization, E-government, Local government, Challenges. Paper type — Research paper....
Realizable planar gradient-index solar lenses.
Kotsidas, Panagiotis; Modi, Vijay; Gordon, Jeffrey M
2012-04-01
The design of single element planar hemispherical gradient-index solar lenses that can accommodate the constraints of realistic materials and fabrication techniques are presented, and simulated with an extended and polychromatic solar source for concentrator photovoltaics at flux concentration values exceeding 1000 suns. The planar hemispherical far-field lens is created from a near-field unit magnification spherical gradient-index design, and illustrated with an f/1.40 square solar lens that allows lossless packing within a concentrator module.
Generating physically realizable stellar structures via embedding
Energy Technology Data Exchange (ETDEWEB)
Maurya, S.K. [University of Nizwa, Department of Mathematical and Physical Sciences, College of Arts and Science, Nizwa (Oman); Govender, M. [Durban University of Technology, Department of Mathematics, Faculty of Applied Sciences, Durban (South Africa)
2017-05-15
In this work we present an exact solution of the Einstein-Maxwell field equations describing compact charged objects within the framework of classical general relativity. Our model is constructed by embedding a four-dimensional spherically symmetric static metric into a five-dimensional flat metric. The source term for the matter field is composed of a perfect fluid distribution with charge. We show that our model obeys all the physical requirements and stability conditions necessary for a realistic stellar model. Our theoretical model approximates observations of neutron stars and pulsars to a very good degree of accuracy. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Goon, Garrett [Institute of Physics, Universiteit van Amsterdam,Science Park 904, Amsterdam, 1090 GL (Netherlands)
2017-01-11
We study the effects of heavy fields on 4D spacetimes with flat, de Sitter and anti-de Sitter asymptotics. At low energies, matter generates specific, calculable higher derivative corrections to the GR action which perturbatively alter the Schwarzschild-(A)dS family of solutions. The effects of massive scalars, Dirac spinors and gauge fields are each considered. The six-derivative operators they produce, such as ∼R{sup 3} terms, generate the leading corrections. The induced changes to horizon radii, Hawking temperatures and entropies are found. Modifications to the energy of large AdS black holes are derived by imposing the first law. An explicit demonstration of the replica trick is provided, as it is used to derive black hole and cosmological horizon entropies. Considering entropy bounds, it’s found that scalars and fermions increase the entropy one can store inside a region bounded by a sphere of fixed size, but vectors lead to a decrease, oddly. We also demonstrate, however, that many of the corrections fall below the resolving power of the effective field theory and are therefore untrustworthy. Defining properties of black holes, such as the horizon area and Hawking temperature, prove to be remarkably robust against higher derivative gravitational corrections.
Bootstrapping realized volatility and realized beta under a local Gaussianity assumption
DEFF Research Database (Denmark)
Hounyo, Ulrich
The main contribution of this paper is to propose a new bootstrap method for statistics based on high frequency returns. The new method exploits the local Gaussianity and the local constancy of volatility of high frequency returns, two assumptions that can simplify inference in the high frequency...... context, as recently explained by Mykland and Zhang (2009). Our main contributions are as follows. First, we show that the local Gaussian bootstrap is firstorder consistent when used to estimate the distributions of realized volatility and ealized betas. Second, we show that the local Gaussian bootstrap...... matches accurately the first four cumulants of realized volatility, implying that this method provides third-order refinements. This is in contrast with the wild bootstrap of Gonçalves and Meddahi (2009), which is only second-order correct. Third, we show that the local Gaussian bootstrap is able...
The Semantic Web: From Representation to Realization
Thórisson, Kristinn R.; Spivack, Nova; Wissner, James M.
A semantically-linked web of electronic information - the Semantic Web - promises numerous benefits including increased precision in automated information sorting, searching, organizing and summarizing. Realizing this requires significantly more reliable meta-information than is readily available today. It also requires a better way to represent information that supports unified management of diverse data and diverse Manipulation methods: from basic keywords to various types of artificial intelligence, to the highest level of intelligent manipulation - the human mind. How this is best done is far from obvious. Relying solely on hand-crafted annotation and ontologies, or solely on artificial intelligence techniques, seems less likely for success than a combination of the two. In this paper describe an integrated, complete solution to these challenges that has already been implemented and tested with hundreds of thousands of users. It is based on an ontological representational level we call SemCards that combines ontological rigour with flexible user interface constructs. SemCards are machine- and human-readable digital entities that allow non-experts to create and use semantic content, while empowering machines to better assist and participate in the process. SemCards enable users to easily create semantically-grounded data that in turn acts as examples for automation processes, creating a positive iterative feedback loop of metadata creation and refinement between user and machine. They provide a holistic solution to the Semantic Web, supporting powerful management of the full lifecycle of data, including its creation, retrieval, classification, sorting and sharing. We have implemented the SemCard technology on the semantic Web site Twine.com, showing that the technology is indeed versatile and scalable. Here we present the key ideas behind SemCards and describe the initial implementation of the technology.
Preparation and realization of HPP Zilina
International Nuclear Information System (INIS)
Cizik, F.
1997-01-01
The results achieved in finishing of the preparation and in realization of the Hydro Power Project (HPP) Zilina proved advantageousness of such approach even if an increasing presence of eccentric competing interests should be mentioned. Integration of mutual interest within the established company limited by shares means to create equal conditions for all of the partners and not a power liquidation of specificities and not a power liquidation of specificities, specialties and individualities, both of value and legal ones. HPPs with power utilization must be built in such places in which there are suitable conditions for their operation created by the nature on a stream. Their power contribution is, as a rule, a contribution for the whole electric system. The part beneficial to the public is a contribution for the region affected by the construction. During the construction, they offer jobs not only, but especially, for the residents of the region affected by the construction but also for workers in cement works, brick works, steels works, and other kinds of industries providing supplies for the construction, industry of services. Changes in legislation supporting construction of HPPs with power utilization, purchasing system and electric energy prices remain still unsolved. Energy prices are distorted compared to relations in western in western market economies and do not allow either reproduction of a production base or gain and pay back the credits and compound interest. An additional idea of the state about financing the part of HPPs with power utilization beneficial to the public from resources gained in operation of the built objects without any form of easement of taxation and changes shifts a return of invested resources behind a border of an entrepreneurial interest
Gkillas (Gillas), Konstantinos; Vortelinos, Dimitrios I.; Saha, Shrabani
2018-02-01
This paper investigates the properties of realized volatility and correlation series in the Indian stock market by employing daily data converting to monthly frequency of five different stock indices from January 2, 2006 to November 30, 2014. Using non-parametric estimation technique the properties examined include normality, long-memory, asymmetries, jumps, and heterogeneity. The realized volatility is a useful technique which provides a relatively accurate measure of volatility based on the actual variance which is beneficial for asset management in particular for non-speculative funds. The results show that realized volatility and correlation series are not normally distributed, with some evidence of persistence. Asymmetries are also evident in both volatilities and correlations. Both jumps and heterogeneity properties are significant; whereas, the former is more significant than the latter. The findings show that properties of volatilities and correlations in Indian stock market have similarities as that show in the stock markets in developed countries such as the stock market in the United States which is more prevalent for speculative business traders.
International Nuclear Information System (INIS)
Chau, L.L.
1984-01-01
Integrable properties, i.e., existence of linear systems, infinite number of conservation laws, Riemann-Hilbert transforms, affine Lie algebra of Kac-Moody, and Bianchi-Backlund transformation, are discussed for the constraint equations of the supersymmetric Yang-Mills fields. For N ≥ 3 these constraint equations give equations of motion of the fields. These equations of motion reduce to the ordinary Yang-Mills equations as the spinor and scalar fields are eliminated. These understandings provide a possible method to solve the full Yang-Mills equations. Connections with other non-linear systems are also discussed
String-localized quantum fields and modular localization
Energy Technology Data Exchange (ETDEWEB)
Mund, J. [Juiz de Fora Univ., MG (Brazil). Dept. de Fisica; Schroer, B. [FU-Berlin, Berlin (Germany). Inst. fuer Theoretische Physik; Yngvason, J. [Erwin Schroedinger Institute for Mathematical Physics, Vienna (Austria)
2005-12-15
We study free, covariant, quantum (Bose) fields that are associated with irreducible representations of the Poincare group and localized in semi-infinite strings extending to spacelike infinity. Among these are fields that generate the irreducible representations of mass zero and infinite spin that are known to be incompatible with point-like localized fields. For the massive representation and the massless representations of finite helicity, all string-localized free fields can be written as an integral, along the string, of point-localized tensor or spinor fields. As a special case we discuss the string-localized vector fields associated with the point-like electromagnetic field and their relation to the axial gauge condition in the usual setting. (author)
String-localized quantum fields and modular localization
International Nuclear Information System (INIS)
Mund, J.
2005-12-01
We study free, covariant, quantum (Bose) fields that are associated with irreducible representations of the Poincare group and localized in semi-infinite strings extending to spacelike infinity. Among these are fields that generate the irreducible representations of mass zero and infinite spin that are known to be incompatible with point-like localized fields. For the massive representation and the massless representations of finite helicity, all string-localized free fields can be written as an integral, along the string, of point-localized tensor or spinor fields. As a special case we discuss the string-localized vector fields associated with the point-like electromagnetic field and their relation to the axial gauge condition in the usual setting. (author)
Realization of the Najafi-Golestanian microswimmer
Hubert, Maxime; Grosjean, Galien; Lagubeau, Guillaume; Vandewalle, Nicolas; Grasp Lab, Cesam Research Unit Team; Departamento de Fısica Team
The development of artificial microswimmers, microscopic robots that swim in a fluid like sperm cells and motile bacteria, could cause a leap forward in various fields such as microfluidics, microsystems, or minimally invasive medicine. Nature provides plenty of examples of efficient microswimmers. However, a bottom-up approach, looking at the simplest ingredients needed to generate a microswimmer, can lead to a deeper understanding of the swimming problem. First described by Najafi and Golestanian, a paradigmatic microswimmer is the three-linked-spheres model, which follows a minimalist approach for propulsion by shape shifting. In this presentation, we describe the experimental realisation of this microswimmer using self-assembled ferromagnetic particle at an air-water interface, powered by an uniform oscillating magnetic field. A model, using two harmonic oscillators, reproduces the experimental findings. Because the model remains general, the same approach could be used to design a variety of efficient microswimmers.
Experimental Realization of a Quantum Spin Pump
DEFF Research Database (Denmark)
Watson, Susan; Potok, R.; M. Marcus, C.
2003-01-01
We demonstrate the operation of a quantum spin pump based on cyclic radio-frequency excitation of a GaAs quantum dot, including the ability to pump pure spin without pumping charge. The device takes advantage of bidirectional mesoscopic fluctuations of pumped current, made spin......-dependent by the application of an in-plane Zeeman field. Spin currents are measured by placing the pump in a focusing geometry with a spin-selective collector....
Realization of an endoscope equipped with microprojection system for optogenetics
Baumgartner, Ryan; Falk, Ryan; Pashaie, Ramin
2012-03-01
Optogenetics is the science where recent progresses in the field of photonics are combined with the techniques in molecular genetics to develop a methodology for modulation of neural activities.1-9 Despite enormous enthusiasm in using optogenetics for brain studies, little has been done on the engineering side such as technology development for light delivery or realization of reliable systems for optical monitoring of the induced activities. In this project, we have implemented a Digital Micromirror Device based microprojection system capable of delivering illumination patterns through a high-resolution imaging fiber bundle that guides the pattern to the region of interest on the surface or within the brain tissue. The system is also equipped with an imaging path for detection of calcium signals and monitoring the induced patterns of cellular activities. A very interesting application of the system is extracting topographic computational maps of cortex or cellular receptive fields in-vivo. It is known that such maps are the engine of information processing in the cortex. Better understanding of the structure of such maps will help to unravel the mysteries of brain higher level computations. Another application of this system is related to the high-resolution stimulation patterns that cannot be produced with electrode arrays. Production of high-resolution patterns is important in the study of specific modes of brain activities. We report the details of our optical design, preliminary results produced by testing the system on tissue, and we discuss our strategy to extract new data from the brain tissue.
DEFF Research Database (Denmark)
Hansen, Peter Reinhard; Lunde, Asger; Voev, Valeri
the model to market returns in conjunction with an individual asset yields a model for the conditional regression coefficient, known as the beta. We apply the model to a set of highly liquid stocks and find that conditional betas are much more variable than usually observed with rolling-window OLS...... regressions with dailty data. In the empirical part of the paper we examine the cross-sectional as well as the time variation of the conditional beta series. The model links the conditional and realized second moment measures in a self-contained system of equations, making it amenable to extensions and easy...
Realized gains from block-plot coastal Douglas-fir trials in the northern Oregon Cascades
Terrence Z. Ye; Keith J.S. Jayawickrama; J. Bradley. St. Clair
2010-01-01
Realized gains for coastal Douglas-fir (Pseudotsuga menziesii var. menziesii) were evaluated using data collected from 15-year-old trees from five field trials planted in large block plots in the northern Oregon Cascades. Three populations with different genetic levels (elite--high predicted gain; intermediate--moderate predicted gain; and an...
Success factors in the realization of large ice projects in education
Pronk, Arno; Luo, Peng; Li, Q.; Sanders, F.C.; Overtoom, M.E.; Coar, Lancelot; Bögle, Annette; Grohmann, Manfred
There has been a long tradition in making ice structures, but the development of technical improvements for making ice buildings is a new field with just a handful of researchers. Most of the projects were realized by professors in cooperation with their students as part of their education in
ROLE OF PROFESSIONAL IDENTITY IN SELF-REALIZATION OF PSYCHOLOGISTS-TEACHERS
Directory of Open Access Journals (Sweden)
S I Kudinov
2015-12-01
Full Text Available The article highlights the problem of the role of professional identity in self-realization of psychologists- teachers. Within the frame of a system-defined approach the research identifies and describes the individual- typological features of the phenomena interesting to us. The works that focus on the study of self-realization are subjected to the analysis, as the result it is noted that in this field there are still gaps in the understanding of this issue. Thus, the study from the perspective of the influence of professional identity on the successful self-realization of the personality is recognized as relevant. In the framework of this study the following assumptions are put forward: there is a relationship between the professional identity and successful self- realization of the personality; the level of formation of professional identity has an impact on the success of personality self-realization; the professional identity not fully formed acts as a barrier for creativity, activity, internality and constructive self- realization; fully formed professional identity provides a high success rate of self-realization. The purpose of this study was to investigate the features of self- realization and professional identity of psychologists-teachers. For the study, we used “Multidimensional questionnaire of personality self-realization” (MQPS by S.I. Kudinov, for the study of professional identity the following methods were used: “Professional identity-marginalism” questionnaire by E.P. Ermolaeva and Methods of measuring professional identity (MMPI by L.B. Schneider. The results obtained were subjected to quantitative analysis. In the article the author relies on the data gathered as a result of a study conducted at the Institute of Education Development of the Republic of Bashkortostan (GAOU DPO IRO RB, city of Ufa. The sample consisted of 142 educational psychologists. As a result of the conducted research, the specific relationship
Realization of Bohr-like circular wavepackets
Mestayer, Jeff; Wyker, B.; Dunning, F. B.; Reinhold, C.; Yoshida, S.; Burgdörfer, J.
2008-05-01
We demonstrate a protocol to create localized wavepackets in very-high n Rydberg states that travel in near-circular orbits around the nucleus. Although these wavepackets slowly dephase and eventually lose their localization, their motion can be followed for several orbital periods. These wavepackets represent the closest analog yet achieved to the original Bohr model of the atom, i.e., an electron in circular classical orbit around the nucleus. The time evolution of the momentum and position of the wavepackets is monitored using, respectively, short half-cycle pulses and sudden field steps, which are applied after a variable time delay and along different directions. The present technique is explained with the aid of CTMC simulations, and possible extension to creation of elusive ``planetary atoms'' in highly correlated stable multiply-excited states is discussed. Research supported by the NSF, the Robert A. Welch Foundation, the OBES, U.S. DoE to ORNL, and by the FWF (Austria).
Banda Guzmán, V. M.; Kirchbach, M.
2016-09-01
A boson of spin j≥ 1 can be described in one of the possibilities within the Bargmann-Wigner framework by means of one sole differential equation of order twice the spin, which however is known to be inconsistent as it allows for non-local, ghost and acausally propagating solutions, all problems which are difficult to tackle. The other possibility is provided by the Fierz-Pauli framework which is based on the more comfortable to deal with second-order Klein-Gordon equation, but it needs to be supplemented by an auxiliary condition. Although the latter formalism avoids some of the pathologies of the high-order equations, it still remains plagued by some inconsistencies such as the acausal propagation of the wave fronts of the (classical) solutions within an electromagnetic environment. We here suggest a method alternative to the above two that combines their advantages while avoiding the related difficulties. Namely, we suggest one sole strictly D^{(j,0)oplus (0,j)} representation specific second-order differential equation, which is derivable from a Lagrangian and whose solutions do not violate causality. The equation under discussion presents itself as the product of the Klein-Gordon operator with a momentum-independent projector on Lorentz irreducible representation spaces constructed from one of the Casimir invariants of the spin-Lorentz group. The basis used is that of general tensor-spinors of rank 2 j.
The Realization and Study of Optical Wings
Artusio-Glimpse, Alexandra Brae
Consider the airfoil: a carefully designed structure capable of stable lift in a uniform air flow. It so happens that air pressure and radiation (light) pressure are similar phenomena because each transfer momentum to flow-disturbing objects. This, then, begs the question: does an optical analogue to the airfoil exist? Though an exceedingly small effect, scientists harness radiation pressure in a wide gamut of applications from micromanipulation of single biological particles to the propulsion of large spacecrafts called solar sails. We introduce a cambered, refractive rod that is subjected to optical forces analogous to those seen in aerodynamics, and I call this analogue the optical wing. Flight characteristics of optical wings are determined by wing shape and material in a uniform radiation field. Theory predicts the lift force and axial torque are functions of the wing's angle of attack with stable and unstable orientations. These structures can operate as intensity-dependent, parametrically driven oscillators. In two-dimensions, the wings exhibit bistability when analyzed in an accelerating frame. In three-dimensions, the motion of axially symmetric spinning hemispherical wings is analogous to a spinning top. Experiments on semi-buoyant wings in water found semicylindrically shaped, refractive microparticles traversed a laser beam and rotated to an illumination-dependent stable orientation. Preliminary tests aid in the development of a calibrated force measurement experiment to directly evaluate the optical forces and torque on these samples. A foundational study of the optical wing, this work contributes to future advancements of flight-by-light.
Design and Realization of Network Teaching System
Directory of Open Access Journals (Sweden)
Ji Shan Shan
2016-01-01
Full Text Available Since 21 century, with the wide spread in family and public, network has been applied in many new fields, and the application in classes is of no exception. In traditional education, teachers give lessons to students face to face. Hence, the teaching quality depends largely on the quality and initiative of the individual teacher. However, the serious disadvantages of this mode are that teachers completely dominate the classroom and may ignore the subjective cognition role of the students, which may be bad for the growth of creativity and the innovative thinking ability. Obviously, traditional education mode cannot meet the requirements of the this new era which leads to the booming developing tendency of the network. As a new teaching measure, scientifically combining modern information technology and teaching practice, network teaching not only changes the traditional education by the means and form, but even also gives new meanings to teaching concept, process, method as well as teacher-student role and other deep levels. With the help of network teaching system, on-line classroom learning, relevant information systematization, standardization and automation, this system provides students with an efficient online learning method with high quality. This also helps to solve the disadvantages of the traditional teaching mode and promote the teaching methods to a new stage. It improves the network teaching platform, enriches the network teaching resources, and establishes a network teaching system, so as to improve information quality of teachers and students and assist in improving teaching quality of schools.
Realizing Technologies for Magnetized Target Fusion
Energy Technology Data Exchange (ETDEWEB)
Wurden, Glen A. [Los Alamos National Laboratory
2012-08-24
Researchers are making progress with a range of magneto-inertial fusion (MIF) concepts. All of these approaches use the addition of a magnetic field to a target plasma, and then compress the plasma to fusion conditions. The beauty of MIF is that driver power requirements are reduced, compared to classical inertial fusion approaches, and simultaneously the compression timescales can be longer, and required implosion velocities are slower. The presence of a sufficiently large Bfield expands the accessibility to ignition, even at lower values of the density-radius product, and can confine fusion alphas. A key constraint is that the lifetime of the MIF target plasma has to be matched to the timescale of the driver technology (whether liners, heavy ions, or lasers). To achieve sufficient burn-up fraction, scaling suggests that larger yields are more effective. To handle the larger yields (GJ level), thick liquid wall chambers are certainly desired (no plasma/neutron damage materials problem) and probably required. With larger yields, slower repetition rates ({approx}0.1-1 Hz) for this intrinsically pulsed approach to fusion are possible, which means that chamber clearing between pulses can be accomplished on timescales that are compatible with simple clearing techniques (flowing liquid droplet curtains). However, demonstration of the required reliable delivery of hundreds of MJ of energy, for millions of pulses per year, is an ongoing pulsed power technical challenge.
The Method of Realizing IPLL with Software
Directory of Open Access Journals (Sweden)
Lingzhi Xia
2014-12-01
Full Text Available The concept of Phase-locked loop is earliest described in the 1820’s. In the late 1970 s, the theory of phase locked loop was given good description, but because of the difficulty of hardware implementation of a phase-locked loop, phase-locked loop, until a long time, was not widely used. In the 1970’s, with the rapidly development of integrated circuit (IC, PLL was widely used in modern communication system. Since then, the phase-locked loop had made great progress, and it was transferred from the earlier only used in field of high precision equipment to the all kinds of electronic products used in the consumer. Due to the rapid development of power system, power system signal analysis is more and more important. In this paper, according to the characteristics of the virtual radio technology and the basic principle of phase-locked loop to build software phase-locked loop, through the analysis of the improved phase-locked loop (IPLL, designed IPLL by way of the software. In this paper, based on the MATLAB simulation, the above analysis shows that the software phase-locked loop can be extracted grid signal, frequency, amplitude and phase of fundamental wave information for demand.
Realized Bond-Stock Correlation: Macroeconomic Announcement Effects
DEFF Research Database (Denmark)
Christiansen, Charlotte; Ranaldo, Angelo
2005-01-01
We investigate the effects of macroeconomic announcements on the realized correlation between bond and stock returns. Our results deliver insights into the dominating drivers of bond-stock comovements. We find that it is not so much the surprise component of the announcement, but the mere fact...... that an announcement occurs that influences the realized bond-stock correlation. The impact of macroeconomic announcements varies across the business cycle. Announcement effects are highly dependent on the sign of the realized bond-stock correlation which has recently gone from positive to negative. Macroeconomic...... announcement effects on realized bond and stock volatilities are also investigated....
A Realization of Theoretical Maximum Performance in IPSec on Gigabit Ethernet
Onuki, Atsushi; Takeuchi, Kiyofumi; Inada, Toru; Tokiniwa, Yasuhisa; Ushirozawa, Shinobu
This paper describes “IPSec(IP Security) VPN system" and how it attains a theoretical maximum performance on Gigabit Ethernet. The Conventional System is implemented by software. However, the system has several bottlenecks which must be overcome to realize a theoretical maximum performance on Gigabit Ethernet. Thus, we newly propose IPSec VPN System with the FPGA(Field Programmable Gate Array) based hardware architecture, which transmits a packet by the pipe-lined flow processing and has 6 parallel structure of encryption and authentication engines. We show that our system attains the theoretical maximum performance in the short packet which is difficult to realize until now.
Singh, Sanjay; Sharma, Arati; Robertson, Gavin P
2012-11-15
Nanotechnology has the potential to make smart drugs that would be capable of targeting cancer but not normal cells and to load combinations of cooperating agents into a single nanosized particle to more effectively treat this disease. However, to realize the full potential of this technology, the negative aspects associated with these nanoparticles need to be overcome. This review discusses concerns in the field limiting realization of the full clinical potential of this technology, which are toxicity and targeted delivery. Strategies to overcome these hurdles are also reviewed, which could lead to attainment of the full clinical potential of this exciting technology. ©2012 AACR.
Singh, Sanjay; Sharma, Arati; Robertson, Gavin P.
2013-01-01
Nanotechnology has the potential to make smart drugs that would be capable of targeting cancer but not normal cells and loading combinations of cooperating agents into a single nano-sized particle to more effectively treat this disease. However, to realize the full potential of this technology the negative aspects associated with these nanoparticles needs to be overcome. This review discusses concerns in the field limiting realization of the full clinical potential of this technology, which are toxicity and targeted delivery. Strategies to overcome these hurdles are also reviewed which could lead to attainment of the full clinical potential of this exciting technology. PMID:23139207
Dirac bound states of anharmonic oscillator in external fields
Energy Technology Data Exchange (ETDEWEB)
Hamzavi, Majid, E-mail: majid.hamzavi@gmail.com [Department of Physics, University of Zanjan, Zanjan (Iran, Islamic Republic of); Ikhdair, Sameer M., E-mail: sikhdair@gmail.com [Department of Physics, Faculty of Science, an-Najah National University, Nablus, West Bank, Palestine (Country Unknown); Department of Electrical and Electronic Engineering, Near East University, 922022 Nicosia, Northern Cyprus, Mersin 10 (Turkey); Falaye, Babatunde J., E-mail: fbjames11@physicist.net [Theoretical Physics Section, Department of Physics, University of Ilorin, P. M. B. 1515, Ilorin (Nigeria)
2014-02-15
We explore the effect of the external magnetic and Aharonov–Bohm (AB) flux fields on the energy levels of Dirac particle subjects to mixed scalar and vector anharmonic oscillator field in the two-dimensional (2D) space. We calculate the exact energy eigenvalues and the corresponding un-normalized two-spinor-components wave functions in terms of the chemical potential parameter, magnetic field strength, AB flux field and magnetic quantum number by using the Nikiforov–Uvarov (NU) method. -- Highlights: • Effect of the external fields on the energy levels of Dirac particle with the anharmonic oscillator is investigated. • The solutions are discussed in view of spin and pseudospin symmetries limits. • The energy levels and wave function are presented by the Nikiforov–Uvarov method.
Dirac bound states of anharmonic oscillator in external fields
International Nuclear Information System (INIS)
Hamzavi, Majid; Ikhdair, Sameer M.; Falaye, Babatunde J.
2014-01-01
We explore the effect of the external magnetic and Aharonov–Bohm (AB) flux fields on the energy levels of Dirac particle subjects to mixed scalar and vector anharmonic oscillator field in the two-dimensional (2D) space. We calculate the exact energy eigenvalues and the corresponding un-normalized two-spinor-components wave functions in terms of the chemical potential parameter, magnetic field strength, AB flux field and magnetic quantum number by using the Nikiforov–Uvarov (NU) method. -- Highlights: • Effect of the external fields on the energy levels of Dirac particle with the anharmonic oscillator is investigated. • The solutions are discussed in view of spin and pseudospin symmetries limits. • The energy levels and wave function are presented by the Nikiforov–Uvarov method
International Nuclear Information System (INIS)
Chau, L.L.
1983-01-01
Integrable properties, i.e., existence of linear systems, infinite number of conservation laws, Reimann-Hilbert transforms, affine Lie algebra of Kac-Moody, and Bianchi-Baecklund transformation, are discussed for the constraint equations of the supersymmetric Yang-Mills fields. For N greater than or equal to 3 these constraint equations give equations of motion of the fields. These equations of motion reduce to the ordinary Yang-Mills equations as the spinor and scalar fields are eliminated. These understandings provide a possible method to solve the full Yang-Mills equations. Connections with other non-linear systems are also discussed. 53 references
Hardware realization of an SVM algorithm implemented in FPGAs
Wiśniewski, Remigiusz; Bazydło, Grzegorz; Szcześniak, Paweł
2017-08-01
The paper proposes a technique of hardware realization of a space vector modulation (SVM) of state function switching in matrix converter (MC), oriented on the implementation in a single field programmable gate array (FPGA). In MC the SVM method is based on the instantaneous space-vector representation of input currents and output voltages. The traditional computation algorithms usually involve digital signal processors (DSPs) which consumes the large number of power transistors (18 transistors and 18 independent PWM outputs) and "non-standard positions of control pulses" during the switching sequence. Recently, hardware implementations become popular since computed operations may be executed much faster and efficient due to nature of the digital devices (especially concurrency). In the paper, we propose a hardware algorithm of SVM computation. In opposite to the existing techniques, the presented solution applies COordinate Rotation DIgital Computer (CORDIC) method to solve the trigonometric operations. Furthermore, adequate arithmetic modules (that is, sub-devices) used for intermediate calculations, such as code converters or proper sectors selectors (for output voltages and input current) are presented in detail. The proposed technique has been implemented as a design described with the use of Verilog hardware description language. The preliminary results of logic implementation oriented on the Xilinx FPGA (particularly, low-cost device from Artix-7 family from Xilinx was used) are also presented.
Hofstadter butterflies in nonlinear Harper lattices, and their optical realizations
Energy Technology Data Exchange (ETDEWEB)
Manela, Ofer; Segev, Mordechai [Department of Physics and Solid State Institute, Technion, Haifa 32000 (Israel); Christodoulides, Demetrios N [College of Optics/CREOL, University of Central Florida, FL 32816-2700 (United States); Kip, Detlef, E-mail: msegev@tx.technion.ac.i [Department of Electrical Engineering, Helmut Schmidt University, 22043 Hamburg (Germany)
2010-05-15
The ubiquitous Hofstadter butterfly describes a variety of systems characterized by incommensurable periodicities, ranging from Bloch electrons in magnetic fields and the quantum Hall effect to cold atoms in optical lattices and more. Here, we introduce nonlinearity into the underlying (Harper) model and study the nonlinear spectra and the corresponding extended eigenmodes of nonlinear quasiperiodic systems. We show that the spectra of the nonlinear eigenmodes form deformed versions of the Hofstadter butterfly and demonstrate that the modes can be classified into two families: nonlinear modes that are a 'continuation' of the linear modes of the system and new nonlinear modes that have no counterparts in the linear spectrum. Finally, we propose an optical realization of the linear and nonlinear Harper models in transversely modulated waveguide arrays, where these Hofstadter butterflies can be observed. This work is relevant to a variety of other branches of physics beyond optics, such as disorder-induced localization in ultracold bosonic gases, localization transition processes in disordered lattices, and more.
[The design and realization of Web-view PACS browser].
Yu, Pei-liang; Ye, Zhi-qian
2006-05-01
This article analyses the system structure and realization model of Web-view PACS browser in combination with the characteristic of PACS, and presents the realizing process of the web-view PACS browser using JSP mode and B/S model.
Psychological Features of Self-Realization in Chinese Women
Directory of Open Access Journals (Sweden)
S I Kudinov
2013-12-01
Full Text Available The article analyzes the results of the empirical study of self-realization of an individual. The study was performed on the Chinese respondents in the frame of the polysystemic concept of self-realization of the personality.
Exponential GARCH Modeling with Realized Measures of Volatility
DEFF Research Database (Denmark)
Hansen, Peter Reinhard; Huang, Zhuo
returns and volatility. We apply the model to DJIA stocks and an exchange traded fund that tracks the S&P 500 index and find that specifications with multiple realized measures dominate those that rely on a single realized measure. The empirical analysis suggests some convenient simplifications...
Aspect-Oriented Change Realizations and Their Interaction
DEFF Research Database (Denmark)
Vranić, Valentino; Menkyna, Radoslav; Bebjak, Michal
2009-01-01
With aspect-oriented programming, changes can be treated explicitly and directly at the programming language level. An approach to aspect-oriented change realization based on a two-level change type model is presented in this paper. In this approach, aspect-oriented change realizations are mainly...
An exact realization of the Kac-Moody algebra
International Nuclear Information System (INIS)
Baaquie, B.E.
1986-06-01
The Kac-Moody generators are explicitly realized as functional differential operators expressed in terms of the co-ordinates of the (infinite dimensional) group manifold. As an application of this realization, the two-dimensional Wess-Zumino chiral action is derived from the Hamiltonian formulation. (author)
Proposal of Realization Restricted Quantum Game with Linear Optic Method
International Nuclear Information System (INIS)
Zhao Haijun; Fang Ximing
2006-01-01
We present a quantum game with the restricted strategic space and its realization with linear optical system, which can be played by two players who are separated remotely. This game can also be realized on any other quantum computers. We find that the constraint brings some interesting properties that are useful for making game models.
Demonstrating and Testing the BML Compliance of BML Realizers
van Welbergen, H.; Xu, Yuyu; Thiebaux, Marcus; Feng, Wei-Wen; Fu, Jingqiao; Reidsma, Dennis; Shapiro, Ari; Vilhjalmsson, Hannes Högni; Kopp, Stefan; Marsella, Stacy; Thorisson, Kristinn R.
BML realizers are complex software modules that implement a standardized interface -the BML specication language- to steer the behavior of a virtual human. We aim to promote and test the compliance of realizers that implement this interface. To this end we contribute a corpus of example BML scripts
Technology Education: The Means to the Realization of Nigeria's ...
African Journals Online (AJOL)
The realization of Nigeria's vision 2020 is now a challenging problem. However, using Technology Education as a means to the realization is the focus of this paper. This paper highlighted the current state of technology education in Nigeria and stated its efficacy to advance development and improve the nation's economy.
Energy Technology Data Exchange (ETDEWEB)
Alperovich, Igor; Smolentsev, Grigory; Moonshiram, Dooshaye; Jurss, Jonah W.; Concepcion, Javier J.; Meyer, Thomas J.; Soldatov, Alexander; Pushkar, Yulia (UNC); (Purdue); (SFU-Russia); (Lund)
2015-09-17
L{sub 2,3}-edge X-ray absorption spectroscopy (XAS) has demonstrated unique capabilities for the analysis of the electronic structure of di-Ru complexes such as the blue dimer cis,cis-[Ru{sub 2}{sup III}O(H{sub 2}O){sub 2}(bpy){sub 4}]{sup 4+} water oxidation catalyst. Spectra of the blue dimer and the monomeric [Ru(NH{sub 3}){sub 6}]{sup 3+} model complex show considerably different splitting of the Ru L{sub 2,3} absorption edge, which reflects changes in the relative energies of the Ru 4d orbitals caused by hybridization with a bridging ligand and spin-orbit coupling effects. To aid the interpretation of spectroscopic data, we developed a new approach, which computes L{sub 2,3}-edges XAS spectra as dipole transitions between molecular spinors of 4d transition metal complexes. This allows for careful inclusion of the spin-orbit coupling effects and the hybridization of the Ru 4d and ligand orbitals. The obtained theoretical Ru L{sub 2,3}-edge spectra are in close agreement with experiment. Critically, existing single-electron methods (FEFF, FDMNES) broadly used to simulate XAS could not reproduce the experimental Ru L-edge spectra for the [Ru(NH{sub 3}){sub 6}]{sup 3+} model complex nor for the blue dimer, while charge transfer multiplet (CTM) calculations were not applicable due to the complexity and low symmetry of the blue dimer water oxidation catalyst. We demonstrated that L-edge spectroscopy is informative for analysis of bridging metal complexes. The developed computational approach enhances L-edge spectroscopy as a tool for analysis of the electronic structures of complexes, materials, catalysts, and reactive intermediates with 4d transition metals.
Classical field configurations and infrared slavery
Swanson, Mark S.
1987-09-01
The problem of determining the energy of two spinor particles interacting through massless-particle exchange is analyzed using the path-integral method. A form for the long-range interaction energy is obtained by analyzing an abridged vertex derived from the parent theory. This abridged vertex describes the radiation of zero-momentum particles by pointlike sources. A path-integral formalism for calculating the energy of the radiation field associated with this abridged vertex is developed and applications are made to determine the energy necessary for adiabatic separation of two sources in quantum electrodynamics and for an SU(2) Yang-Mills theory. The latter theory is shown to be consistent with confinement via infrared slavery.
Realization of φ Josephson junctions with a ferromagnetic interlayer
International Nuclear Information System (INIS)
Sickinger, Hanna Sabine
2014-01-01
In this thesis, φ Josephson junctions based on 0-π junctions with a ferromagnetic interlayer are studied. Josephson junctions (JJs) with a ferromagnetic interlayer can have a phase drop of 0 or π in the ground state, depending on the thickness of the ferromagnet (0 JJs or π JJs). Also, 0-π JJs can be realized, where one segment of the junction (if taken separately) is in the 0 state, while the other segment is in the π state. One can use these π Josephson junctions as a device in superconducting circuits, where it provides a constant phase shift, i.e., it acts as a π phase battery. A generalization of a π JJ is a φ JJ, which has the phase ±φ in the ground state. The value of φ can be chosen by design and tuned in the interval 0<φ<π. The φ JJs used in this experiment were fabricated as 0-π JJs with asymmetric current densities in the 0 and π facets. This system can be described by an effective current-phase relation which is tunable by an externally applied magnetic field. The first experimental evidence of such a φ JJ is presented in this thesis. In particular it is demonstrated that (a) a φ JJ has two ground states +φ and -φ, (b) the unknown state can be detected (read out) by measuring the critical current I c (I c+ or I c- ), and (c) a particular state can be prepared by applying a magnetic field or a special bias sweep sequence. These properties of a φ JJ can be utilized, for example, as a memory cell (classical bit). Furthermore, a φ Josephson junction can be used as a deterministic ratchet. This is due to the tunable asymmetry of the potential that can be changed by the external magnetic field. Rectification curves are observed for the overdamped and the underdamped case. Moreover, experimental data of the retrapping process of the phase of a φ Josephson junction depending on the temperature is presented.
Structure Design and Realization of Rapid Medicine Dispensing System
Liu, Xiangquan
In this paper, the main components and function of rapid medicine dispensing system is analyzed, structure design of automatic feeding device, sloping storeroom, automatic dispensing device and automatic sorting device is completed. The system adopts medicine conveyer working in with manipulator to realize automatic batch supply of the boxed medicine, adopts sloping storeroom as warehouse of medicine to realize dense depositing, adopts dispensing mechanism which includes elevator, turning panel and electric magnet to realize rapid medicine dispensing, adopts sorting conveyor belt and sorting device to send medicine to designated outlet.
Realization of parking task based on affine system modeling
International Nuclear Information System (INIS)
Kim, Young Woo; Narikiyo, Tatsuo
2007-01-01
This paper presents a motion control system of an unmanned vehicle, where parallel parking task is realized based on a self-organizing affine system modeling and a quadratic programming based robust controller. Because of non-linearity of the vehicle system and complexity of the task to realize, control objective is not always realized with a single algorithm or control mode. This paper presents a hybrid model for parallel parking task in which seven modes for describing sub-tasks constitute an entire model
A multichannel analyzer software system realized by C Language
International Nuclear Information System (INIS)
Zheng Lifang; Xue Liudong
1995-01-01
The specialty of a multichannel analyzer software system realized by C Language is introduced. Because of its superior performance, the software has brilliant prospects for applications. The function of the software is also introduced
Validity of Edgeworth expansions for realized volatility estimators
DEFF Research Database (Denmark)
Hounyo, Ulrich; Veliyev, Bezirgen
The main contribution of this paper is to establish the formal validity of Edgeworth expansions for realized volatility estimators. First, in the context of no microstructure effects, our results rigorously justify the Edgeworth expansions for realized volatility derived in Gonalves and Meddahi...... (2009). Second, we show that the validity of the Edgeworth expansions for realized volatility may not cover the optimal two-point distribution wild bootstrap proposed by Gonçalves and Meddahi (2009). Then, we propose a new optimal nonlattice distribution which ensures the second-order correctness...... of the bootstrap. Third, in the presence of microstructure noise, based on our Edgeworth expansions, we show that the new optimal choice proposed in the absence of noise is still valid in noisy data for the pre-averaged realized volatility estimator proposed by Podolskij and Vetter (2009). Finally, we show how...
Computing weakly reversible realizations of chemical reaction networks
Szederkenyi, Gabor; Hangos, Katalin M.; Tuza, Zsolt
2011-01-01
An algorithm is given in this paper for the computation of dynamically equivalent weakly reversible realizations with the maximal number of reactions, for chemical reaction networks (CRNs) with mass action kinetics.
PRINCIPLES OF FORMATION AND REALIZATION OF REGIONAL INDUSTRIAL POLICY
Directory of Open Access Journals (Sweden)
R.I. Chenenova
2007-09-01
Full Text Available It is analysed existing norm-legal base of realization of regional industrial policy from a position of conformity of principles of its formation and realization to problems of development of the industry in conditions of an openness to the world market. Opportunities of their evolution in the directions promoting becoming of competitive structure of an industrial complex of region are shown.
On the algebraic realization of SU(4) symmetry
International Nuclear Information System (INIS)
Asatryan, G.M.; Zaslavsky, A.N.
1976-01-01
A possibility of nonlinear realization of the symmetry with linearization on the SU(4)xYxC group is discussed. Algebraic properties of SU(4) are restored from the Weinberg condition: amplitudes of goldstone scattering on particles should have a reasonable (as in the Regge theory) asymptotic behaviour. In this case the breaking appears to be minimal. Large values of psi meson masses lead to high-lying charmed trajectories in the SU(4) algebraic realization
THE ROLE OF PERSISTENCE IN STUDENTS’ SELF-REALIZATION
Directory of Open Access Journals (Sweden)
Sergey I. Kudinov
2017-12-01
Full Text Available The paper analyzes the results of an empirical research obtained with the help of a sample of students. The research of persistence was carried out within the framework of the dispositional concept of personality traits and individuality by A. I. Krupnov. The techniques developed by A. I. Krupnov as well as the author’s test of persistence were used in the study. After allocating the levels of persistence, the features of self-realization were analyzed in each group of the respondents. The specificity of self-realization was revealed in the context of the author’s polysystemic concept, the author’s multidimensional questionnaire on personality’s self-realization (MQPSR was used as a diagnostic tool. The empirical study revealed statistically significant differences in the specifics of self-realization of the students with different levels of persistence manifestation. The respondents with a high level of persistence realize themselves more successfully in different spheres of life due to the obvious active behaviour, optimistic attitude, high motivation, creative methods and techniques of self-expression, internal self-regulation and constructive behavior. The students with low persistence lack successful self-realization because of passivity, pessimism, external locus of self-control, a high level of barriers and standard simple schemes of self-expression.
The controllable L-H transition realized by injection of electrons
International Nuclear Information System (INIS)
Pan Yuan; Wang Maoquan; Mao Jianshan; Li Jiangang
1996-02-01
A new way to get and control H mode is proposed. Theoretic analysis and calculation show that the electron injection by pulsed E x B drift can trigger the H mode without direct contact with plasma and could realize the feedback control for the H mode. A repeatable pulsed field and electron beam system with a frequency of 1 k Hz that has been demonstrated enough for HT-6M Tokamak experiment are given in detail. (3 figs.)
Bound states in a model of interaction of Dirac field with material plane
Directory of Open Access Journals (Sweden)
Pismak Yu. M.
2016-01-01
Full Text Available In the framework of the Symanzik approach model of the interaction of the Dirac spinor field with the material plane in the 3 + 1-dimensional space is constructed. The model contains eight real parameters characterizing the properties of the material plane. The general solution of the Euler-Lagrange equations of the model and dispersion equations for bound states are analyzed. It is shown that there is a choice of parameters of the model in which the connected states are characterized by dispersion law of a mass-less particle moving along the material plane with the dimensionless Fermi velocity not exceeding one.
Energy Technology Data Exchange (ETDEWEB)
Loeffler, Andreas
2008-11-05
At the beginning, we improved the three dimensional optical confinement of the micropillars. The quality factor of the pillars could be increased by the use of higher reflectivity mirrors and a matched V/III ratio for the different epitaxial layers. Hence, a record quality factor of about 90000 was achieved for an active micropillar with 26 (30) mirror pairs in the top (bottom) DBR and a diameter of 4 {mu}m. In parallel to this, we made studies on the growth of self-assembled GaInAs quantum dots on GaAs substrates. Here, the nucleation of three dimensional islands as well as their optical properties were object of the investigation. The morphological properties of the dots were analyzed by transmission and scanning electron microscopy, and the optical properties were investigated by photoluminescence and photoreflectance measurements. The optical and particularly the morphological properties of the self-assembled GaInAs quantum dots were essentially improved. Due to a low strain nucleation layer with an indium content of 30 %, the dot density could be reduced to 6-9 x 10{sup 9} cm{sup -2} and their geometric dimensions were increased to typical lengths between 50 and 100 nm and widths of about 30 nm. The lattice mismatch between the quantum dots and the surrounding matrix is decreased due to the reduced indium content. The minimized strain during the dot growth leads to an enhanced migration length of the deposited atoms on the surface. Finally, the obtained findings of the MBE growth of microcavities, their fabrication and the self-assembled island growth of GaInAs on GaAs were used for the realization of further samples. Low strain GaInAs quantum dots were embedded into the microresonators. These structures allowed for the first time the observation of strong coupling between light and matter in a semiconductor. In case of the low strain quantum dots with enlarged dimensions in the strong coupling regime, a vacuum Rabi-splitting of about 140 {mu}eV between the
Higher-spin charges in Hamiltonian form. II. Fermi fields
Energy Technology Data Exchange (ETDEWEB)
Campoleoni, A.; Henneaux, M. [Université Libre de Bruxelles, and International Solvay Institutes,ULB-Campus Plaine CP231, 1050 Brussels (Belgium); Hörtner, S. [Centro de Estudios Científicos (CECs), Casilla 1469, Valdivia (Chile); Leonard, A. [Université Libre de Bruxelles, and International Solvay Institutes,ULB-Campus Plaine CP231, 1050 Brussels (Belgium)
2017-02-10
We build the asymptotic higher-spin charges associated with “improper' gauge transformations for fermionic higher-spin gauge fields on Anti de Sitter backgrounds of arbitrary dimension. This is achieved within the canonical formalism. We consider massless fields of spin s+1/2, described by a symmetric spinor-tensor of rank s in the Fang-Fronsdal approach. We begin from a detailed analysis of the spin 5/2 example, for which we cast the Fang-Fronsdal action in Hamiltonian form, we derive the charges and we propose boundary conditions on the canonical variables that secure their finiteness. We then extend the computation of charges and the characterisation of boundary conditions to arbitrary half-integer spin. Our construction generalises to higher-spin fermionic gauge fields the known Hamiltonian derivation of supercharges in AdS supergravity.
The potential and realized spread of wildfires across Canada.
Wang, Xianli; Parisien, Marc-André; Flannigan, Mike D; Parks, Sean A; Anderson, Kerry R; Little, John M; Taylor, Steve W
2014-08-01
Given that they can burn for weeks or months, wildfires in temperate and boreal forests may become immense (eg., 10(0) - 10(4) km(2) ). However, during the period within which a large fire is 'active', not all days experience weather that is conducive to fire spread; indeed most of the spread occurs on a small proportion (e.g., 1 - 15 days) of not necessarily consecutive days during the active period. This study examines and compares the Canada-wide patterns in fire-conducive weather ('potential' spread) and the spread that occurs on the ground ('realized' spread). Results show substantial variability in distributions of potential and realized spread days across Canada. Both potential and realized spread are higher in western than in eastern Canada; however, whereas potential spread generally decreases from south to north, there is no such pattern with realized spread. The realized-to-potential fire-spread ratio is considerably higher in northern Canada than in the south, indicating that proportionally more fire-conducive days translate into fire progression. An exploration of environmental correlates to spread show that there may be a few factors compensating for the lower potential spread in northern Canada: a greater proportion of coniferous (i.e., more flammable) vegetation, lesser human impacts (i.e., less fragmented landscapes), sufficient fire ignitions, and intense droughts. Because a linear relationship exists between the frequency distributions of potential spread days and realized spread days in a fire zone, it is possible to obtain one from the other using a simple conversion factor. Our methodology thus provides a means to estimate realized fire spread from weather-based data in regions where fire databases are poor, which may improve our ability to predict future fire activity. © 2014 John Wiley & Sons Ltd.
Management of purchase process in realization of building investment
Directory of Open Access Journals (Sweden)
M. Radoń
2010-07-01
Full Text Available In building companies process of product and service purchase is one of the main processes of quality management system [1]. Because ofshort time-limits of contract realization, high specialization of works, necessity of fulfillment of high quality requirements and assurance of profitable financial effects the management of purchase process becomes very important element of work of the building company. The serious problem in creating and keeping the efficient system of purchase management is special type of purchase in building companies. Particular investments are realized in different country regions, objects are built based on the individual design documentations and each building becomes independent organization unit that organize purchase necessary for investment realization.An example of the management system of purchase process in building company is described in the paper. Just In Time system is widelyused during the realization of building investment. This system is especially useful in buildings because some investments, especially inbig cities, are characterized by restriction in building site. This makes impossible storing the products. In such cases close synchronization between times of delivery and requirements of purchase schedule and schedule of building realization is very important. Criteria of supplier selection as well as the methods of choosing the supplier are also presented in the paper. Special attention is paid to necessity of valuation of the purchase efficiency and the purchase risk. Basic coefficients of purchase efficiency are also described in the paper.
Realization of Multistage FIR Filters using Pipelining-Interleaving
Directory of Open Access Journals (Sweden)
M. Ciric
2012-11-01
Full Text Available Multistage digital filters can be one of the solutions for the realization of filters with a narrow transition zone. If requirements for the width of transition zone are too strict, then they are the only alternative, and the decimation/interpolation must be performed in several steps. Combining decimation/interpolation operations related to the implementation of multi-channel filters in the PI (pipelining/interleaving technique can give an efficient structure of multichannel multistage filter. Using the advantages offered by newer generations of FPGA chips in terms of digital design structure, it is possible to realize such filters with considerable savings of hardware resources and reduce the effect of finite length codeword. This paper proposes such an efficient implementation and presents the results of such a realization with FPGA components.
Research and realization of key technology in HILS interactive system
Liu, Che; Lu, Huiming; Wang, Fankai
2018-03-01
This paper designed HILS (Hardware In the Loop Simulation) interactive system based on xPC platform . Through the interface between C++ and MATLAB engine, establish the seamless data connection between Simulink and interactive system, complete data interaction between system and Simulink, realize the function development of model configuration, parameter modification and off line simulation. We establish the data communication between host and target machine through TCP/IP protocol to realize the model download and real-time simulation. Use database to store simulation data, implement real-time simulation monitoring and simulation data management. Realize system function integration by Qt graphic interface library and dynamic link library. At last, take the typical control system as an example to verify the feasibility of HILS interactive system.
Methods of total spectral radiant flux realization at VNIIOFI
Ivashin, Evgeniy; Lalek, Jan; Rybczyński, Andrzej; Ogarev, Sergey; Khlevnoy, Boris; Dobroserdov, Dmitry; Sapritsky, Victor
2018-02-01
VNIIOFI carries out works on realization of independent methods for realization of the total spectral radiant flux (TSRF) of incoherent optical radiation sources - reference high-temperature blackbodies (BB), halogen lamps, and LED with quasi-Lambert spatial distribution of radiance. The paper describes three schemes for measuring facilities using photometers, spectroradiometers and computer-controlled high class goniometer. The paper describes different approaches for TSRF realization at the VNIIOFI National radiometric standard on the basis of high-temperature BB and LED sources, and gonio-spectroradiometer. Further, they are planned to be compared, and the use of fixed-point cells (in particular, based on the high-temperature δ(MoC)-C metal-carbon eutectic with a phase transition temperature of 2583 °C corresponding to the metrological optical “source-A”) as an option instead of the BB is considered in order to enhance calibration accuracy.
RESEMBLANCE OF INDIRECTNESS IN POLITENESS OF EFL LEARNERS’ REQUEST REALIZATIONS
Directory of Open Access Journals (Sweden)
Indawan Syahri
2013-07-01
Full Text Available Abstract: Politeness principles are universally utilized by the speakers of any language when realizing various speech acts. However, the speakers of particular languages relatively apply politeness due to the cultural norms embedded. The present study attempts to delineate how the Indonesian learners of English (ILE apply the politeness principles in request realizations. Specifically it devotes to the types of politeness strategies applied and resemblance of the indirectness in politeness strategies in requesting acts. The FTAs and indirectness are the theoretical bases used to trace the typologies of both politeness and request strategies. The data werere collected by means of certain elicitation techniques, i.e. DCTs and Role-plays. The analyses werere done through three stages; determining request strategies, politeness strategies, and resemblance of indirectness in politeness. The results show that the indirectness generally is parallel to politeness. Besides, some pragmatic transfers are found in terms of applying native-culture norms in realizing target speech acts.
Definition and Proposed Realization of the International Height Reference System (IHRS)
Ihde, Johannes; Sánchez, Laura; Barzaghi, Riccardo; Drewes, Hermann; Foerste, Christoph; Gruber, Thomas; Liebsch, Gunter; Marti, Urs; Pail, Roland; Sideris, Michael
2017-05-01
Studying, understanding and modelling global change require geodetic reference frames with an order of accuracy higher than the magnitude of the effects to be actually studied and with high consistency and reliability worldwide. The International Association of Geodesy, taking care of providing a precise geodetic infrastructure for monitoring the Earth system, promotes the implementation of an integrated global geodetic reference frame that provides a reliable frame for consistent analysis and modelling of global phenomena and processes affecting the Earth's gravity field, the Earth's surface geometry and the Earth's rotation. The definition, realization, maintenance and wide utilization of the International Terrestrial Reference System guarantee a globally unified geometric reference frame with an accuracy at the millimetre level. An equivalent high-precision global physical reference frame that supports the reliable description of changes in the Earth's gravity field (such as sea level variations, mass displacements, processes associated with geophysical fluids) is missing. This paper addresses the theoretical foundations supporting the implementation of such a physical reference surface in terms of an International Height Reference System and provides guidance for the coming activities required for the practical and sustainable realization of this system. Based on conceptual approaches of physical geodesy, the requirements for a unified global height reference system are derived. In accordance with the practice, its realization as the International Height Reference Frame is designed. Further steps for the implementation are also proposed.
Sign and Quantiles of the Realized Stock-Bond Correlation
DEFF Research Database (Denmark)
Aslanidis, Nektarios; Christiansen, Charlotte
We scrutinize the monthly realized stock-bond correlation based upon high frequency returns. In particular, we use a probit model to track the dynamics of the sign of the correlation relative to its various economic forces. The sign is predictable to a large extent with bond market liquidity being...... the most important variable. Moreover, stock market volatility, inflation uncertainty, short rate volatility, and bond volatility have significant effects upon the sign. In addition, we use quantile regressions to pin down the systematic variation of the extreme tails of the realized stock-bond correlation...... of the stock-bond correlation....
PROLOG language application for alarm system realization in accelerator control
International Nuclear Information System (INIS)
Frolov, I.; Vaguine, A.; Abe, I.; Nakahara, K.; Furukawa, K.; Kamikubota, N.
1994-01-01
Such PROLOG features as backtracking, matching and recursive data representation are powerful tools for ALARM system realization. Although the main idea is the possibility to describe some technical system in recursive form, backtracking and matching are ideal for processing recursive data structures. This paper represents a technique which would allow PROLOG language application for ALARM system realization using an example of the KEK LINAC magnet system. The technique is based on an object-oriented internal data representation in terms of objects, properties, relations and knowledge conception. In addition, each property value is characterized by a typical 'time life'. (author)
Polylingual Education Realization, Based on Ethnolingual Didactic Approach
Directory of Open Access Journals (Sweden)
Gulnara T. Smagulova
2013-01-01
Full Text Available The article examines the problems of polylingual education development in the context of the state program documents, particularly determines socio-pedagogical factors of its realization. The author presents the study of current sociolinguistic issues by means of educational measurement. The article gives brief analysis of ethnolingual didactics definitions by different sources. Ethnolingual didactic approach is defined as the strategic methodological feature for the realization of polylingual education, which is the trinity of individual education, upbringing and development as a polylingual personality on the basis of simultaneous acquisition of several languages.
Higher-order Brunnian structures and possible physical realizations
DEFF Research Database (Denmark)
A. Baas, Nils; V. Fedorov, D.; S. Jensen, A.
2014-01-01
to the binding of systems in nature. It now appears that recent generalization to higher order Brunnian structures may potentially be realized as laboratory made or naturally occurring systems. With the binding energy as measure, we discuss possibilities of physical realization in nuclei, cold atoms......, and condensed matter systems. Appearance is not excluded. However, both the form and the strengths of the interactions must be rather special. The most promising subfields for present searches would be in cold atoms because of external control of effective interactions, or perhaps in condensed-matter systems...... with non-local interactions. In nuclei, it would only be by sheer luck due to a lack of tunability....
Graphics processor efficiency for realization of rapid tabular computations
International Nuclear Information System (INIS)
Dudnik, V.A.; Kudryavtsev, V.I.; Us, S.A.; Shestakov, M.V.
2016-01-01
Capabilities of graphics processing units (GPU) and central processing units (CPU) have been investigated for realization of fast-calculation algorithms with the use of tabulated functions. The realization of tabulated functions is exemplified by the GPU/CPU architecture-based processors. Comparison is made between the operating efficiencies of GPU and CPU, employed for tabular calculations at different conditions of use. Recommendations are formulated for the use of graphical and central processors to speed up scientific and engineering computations through the use of tabulated functions
Research and realization of info-net security controlling system
Xu, Tao; Zhang, Wei; Li, Xuhong; Wang, Xia; Pan, Wenwen
2017-03-01
The thesis introduces some relative concepts about Network Cybernetics, and we design and realize a new info-net security controlling system based on Network Cybernetics. The system can control the endpoints, safely save files, encrypt communication, supervise actions of users and show security conditions, in order to realize full-scale security management. At last, we simulate the functions of the system. The results show, the system can ensure the controllability of users and devices, and supervise them real-time. The system can maximize the security of the network and users.
Some quantum optical states as realizations of Lie groups
Directory of Open Access Journals (Sweden)
Abdel-Shafy Fahmy Obada
2011-04-01
Full Text Available We start with the Heisenberg–Weyl algebra and after the definitions of the Fock states we give the definition of the coherent state of this group. This is followed by the exposition of the SU(2 and SU(1,1 algebras and their coherent states. From there we go on describing the binomial state and its extensions as realizations of the SU(2 group. This is followed by considering the negative binomial states, and some squeezed states as realizations of the SU(1,1 group. Generation schemes based on physical systems are mentioned for some of these states.
Mechanism of realization economic strategy of transport organization
Palkina, E. S.
2017-10-01
In modern conditions of economic globalization, high dynamism of external environment, economic strategy of transport organization plays an important role in maintaining its competitive advantages, long-term development. For effective achievement of set strategic goals it is necessary to use an adequate mechanism based on completeness and interrelation of its constituent instruments. The main objective of the study presented in this paper is to develop methodological provisions on formation the mechanism of realization economic strategy for transport organizations. The principles of its construction have been proposed, the key components have been defined. Finally, an attempt to implementation this mechanism into the transport organization management system has been realized.
Star product realizations of kappa-Minkowski space
DEFF Research Database (Denmark)
Durhuus, Bergfinnur; Sitarz, Andrzej
2013-01-01
We define a family of star products and involutions associated with κ -Minkowski space. Applying corresponding quantization maps we show that these star products restricted to a certain space of Schwartz functions have isomorphic Banach algebra completions. For two particular star products...... it is demonstrated that they can be extended to a class of polynomially bounded smooth functions allowing a realization of the full Hopf algebra structure on κ -Minkowski space. Furthermore, we give an explicit realization of the action of the κ -Poincaré algebra as an involutive Hopf algebra on this representation...
Hardware Realization of Chaos Based Symmetric Image Encryption
Barakat, Mohamed L.
2012-06-01
This thesis presents a novel work on hardware realization of symmetric image encryption utilizing chaos based continuous systems as pseudo random number generators. Digital implementation of chaotic systems results in serious degradations in the dynamics of the system. Such defects are illuminated through a new technique of generalized post proceeding with very low hardware cost. The thesis further discusses two encryption algorithms designed and implemented as a block cipher and a stream cipher. The security of both systems is thoroughly analyzed and the performance is compared with other reported systems showing a superior results. Both systems are realized on Xilinx Vetrix-4 FPGA with a hardware and throughput performance surpassing known encryption systems.
THERAPEUTIC SUPPORT OF REALIZATION OF THE COMPETENCE APPROACH IN EDUCATION
Directory of Open Access Journals (Sweden)
Viktoriia A. Lykova
2010-08-01
Full Text Available The article analyses mechanisms of realization of the competence approach in education. Its therapeutic support actualizes factors of nonlinearity, processuality, subjectivity, conformity with nature, feedback in the educational environment. Behind each person there is a variety of tendencies, therefore to foresee or plan, «limit by standards» what exactly will be personally significant for a particular student in pedagogical interaction, is impossible. Therapeutic competence of teachers allows to realize individual learning pathways with support on a «fan of indicators» within a circle of competences.
THE PROCEDURE OF REALIZATION OF THE DIDACTIC PRINCIPLE OF VISUAL METHOD IN AN EDUCATIONAL LABORATORY
Directory of Open Access Journals (Sweden)
Anatolii H. Protasov
2010-08-01
Full Text Available This paper is devoted to the procedure of realization of the main didactic principle – use visual method which becomes an essential factor of student perception of educational sources. The procedure is realized with series of laboratory works which are based on the principle – “device-computer-software”. The transformers of a physical magnitude into electrical signal are used in laboratory works. The combination of these transformers and a computer form the device which can measure a physical magnitude. The software allows reconstructing a virtual field distribution of this magnitude in area and observing its history. MATLAB is used as software and it provides with computation of different physical processes. The proposed procedure provides with a direct visual method and an indirect one as well. This matter promotes forming future specialists’ professional competence.
Additive manufacturing: a new approach to realize complex and unconventional optical components
Heinrich, Andreas; Rank, Manuel; Suresh Nair, Sangeetha; Bauckhage, Y.; Maillard, Phillipe
2017-02-01
In recent years, additive manufacturing methods became more and more prominent. Thereby, these techniques are mainly used in order to realize mechanical components. But the additive manufacturing technology offers a high potential in the field of optics as well. Owing to new design possibilities, completely new solutions are possible. We report on the realization of complex freeform optics using standard 3D printers. We briefly point out the characteristics of 3D printing and its influence on the optical properties. Additionally we address the needed rework of 3D printed optical components. Therefore we apply two different methods - a robot-based fluid jet polishing and a coating method. The advantage of a 3D printed optic lies in its shape complexity. Thus different complex shaped optical elements are discussed. They are used for either metrology tasks or illumination tasks.
International Nuclear Information System (INIS)
Bina, B.; Guenaydin, M.
1997-01-01
We give a complete classification of the real forms of simple non-linear superconformal algebras (SCA) and quasi-superconformal algebras (QSCA) and present a unified realization of these algebras with simple symmetry groups. This classification is achieved by establishing a correspondence between simple non-linear QSCA's and SCA's and quaternionic and super-quaternionic symmetric spaces of simple Lie groups and Lie supergroups, respectively. The unified realization we present involves a dimension zero scalar field (dilaton), dimension-1 symmetry currents, and dimension-1/2 free bosons for QSCA's and dimension-1/2 free fermions for SCA's. The free bosons and fermions are associated with the quaternionic and super-quaternionic symmetric spaces of corresponding Lie groups and Lie supergroups, respectively. We conclude with a discussion of possible applications of our results. (orig.)
Directory of Open Access Journals (Sweden)
R. Seller
2007-09-01
Full Text Available A novel radio channel compensation method aiming to give optimal calibration for microstrip antenna array systems is presented in this paper, realized for an actual DOA measurement antenna system using microstrip antennas to sample the electromagnetic field, operating at 4.5GHz. This new approach considers mismatch between antennas and channel RF ports, channel transmission inequalities, and also decreases the effects of multipath propagation components of calibration reference signals by placing the calibration reference signal feeding network on the microstrip antenna array bearer, directly beside the antenna patches. It is combined with orthogonal spread spectrum calibration signal utility for continuous uninterrupted measurements. The spread spectrum calibration signal is orthogonal to the continuous wave (CW signal to be measured, therefore, the 2 signals can be separated in the receiver, enabling them to be present simultaneously. DOA measurement results are shown, measured with the realized integrated microstrip patch antenna array with calibration network hardware.
Directory of Open Access Journals (Sweden)
M. De la Sen
2008-01-01
Full Text Available This paper investigates key aspects of realization and partial realization theories for linear time-invariant systems being subject to a set of incommensurate internal and external point delays. The results are obtained based on the use of formal Laurent expansions whose coefficients are polynomial matrices of appropriate orders and which are also appropriately related to truncated and infinite block Hankel matrices. The above-mentioned polynomial matrices arise in a natural way from the transcendent equations associated with the delayed dynamics. The results are linked to the properties of controllability and observability of dynamic systems. Some related overview is given related to robustness concerned with keeping the realization properties under mismatching between a current transfer matrix and a nominal one.
Knowledge management as an element in realizing nuclear technology
International Nuclear Information System (INIS)
Schmatjko, K.J.
2007-01-01
Full text: A company is not defined by its competences but it lives in realizing these competences in products. The technical knowledge within the field, i.e. here in nuclear technology, is taken as granted at a first glance. For analyzing the role of knowledge management (KM) in the application this knowledge for our products, one can follow two different dimensions, thereby elucidating the needs and development requirements for KM methods: When first considering the 'operational' dimension, one can start from the scope of the manufacturer's knowledge which covers the construction of plants, then accompanying its life cycle, and pursues the development of the technology for the future. A board spectrum of KM activities has been established yet for these different phases, comprising tools with close product orientation or KM elements applied in 'support processes'. In cases of close KM integration in the business process, diversity over the different sectors of the company has emerged: 'locally' optimized solutions are favoured due to specific requirements of the technical field, to continuity or to ease of daily application. On the other hand, 'global' KM tools are often preferred for integration in 'global' support processes (as human resource (HR) management). This can be illustrated by some examples deployed yet, and their benefit: 1. Feedback procedures for new plant projects: capturing the experience during construction (e.g. by standardised reports), thereby strengthening quality criteria for the project and integrating evaluation into the project management (PM) process of the current project; thus reducing erection time - and related capital cost - for future plants. 2. Follow up event information on nuclear plants globally: by collecting and assessing events systematically for proactive technical action and as input for quality management (QM); thus identifying market needs in advance also. 3. IT based KM tool used in nuclear maintenance service
The Wettzell System Monitoring Concept and First Realizations
Ettl, Martin; Neidhardt, Alexander; Muehlbauer, Matthias; Ploetz, Christian; Beaudoin, Christopher
2010-01-01
Automated monitoring of operational system parameters for the geodetic space techniques is becoming more important in order to improve the geodetic data and to ensure the safety and stability of automatic and remote-controlled observations. Therefore, the Wettzell group has developed the system monitoring software, SysMon, which is based on a reliable, remotely-controllable hardware/software realization. A multi-layered data logging system based on a fanless, robust industrial PC with an internal database system is used to collect data from several external, serial, bus, or PCI-based sensors. The internal communication is realized with Remote Procedure Calls (RPC) and uses generative programming with the interface software generator idl2rpc.pl developed at Wettzell. Each data monitoring stream can be configured individually via configuration files to define the logging rates or analog-digital-conversion parameters. First realizations are currently installed at the new laser ranging system at Wettzell to address safety issues and at the VLBI station O Higgins as a meteorological data logger. The system monitoring concept should be realized for the Wettzell radio telescope in the near future.
Reading on the Internet: Realizing and Constructing Potential Texts
Cho, Byeong-Young; Afflerbach, Peter
2015-01-01
Successful Internet reading requires making strategic decisions about what texts to read and a sequence for reading them, all in accordance with readers' goals. In this paper, we describe the process of realizing and constructing potential texts as an important and critical part of successful Internet reading and use verbal report data to…
Starting Anew: Entrepreneurial Intentions and Realizations Subsequent to Business Closure
V. Schutjens (Veronique); F.C. Stam (Erik)
2006-01-01
textabstractWe know that most businesses fail. But what is not known is to what extent failed ex-entrepreneurs set up in business again. The objective of this article is to explore potential and realized serial entrepreneurship. Based on three disciplines – psychology, labour economics, and the
Exploring Phonetic Realization in Danish by Transformation-Based Learning
DEFF Research Database (Denmark)
Uneson, Marcus; Schachtenhaufen, Ruben
2011-01-01
We align phonemic and semi-narrow phonetic transcriptions in the DanPASS corpus and extend the phonemic description with sound classes and with traditional phonetic features. From this representation, we induce rules for phonetic realization by Transformation-Based Learning (TBL). The rules thus...
Inclusive development as an imperative to realizing the human right ...
African Journals Online (AJOL)
There are a plethora of governance instruments for operationalizing human rights obligations on water and sanitation at multiple levels of governance. The realization that the human right to water and sanitation depends on the discourses and approaches used in a country to implement it implies that it is not self-evident that ...
Exploiting network redundancy for low-cost neural network realizations.
Keegstra, H; Jansen, WJ; Nijhuis, JAG; Spaanenburg, L; Stevens, H; Udding, JT
1996-01-01
A method is presented to optimize a trained neural network for physical realization styles. Target architectures are embedded microcontrollers or standard cell based ASIC designs. The approach exploits the redundancy in the network, required for successful training, to replace the synaptic weighting
Modeling and Forecasting Large Realized Covariance Matrices and Portfolio Choice
Callot, Laurent A.F.; Kock, Anders B.; Medeiros, Marcelo C.
2017-01-01
We consider modeling and forecasting large realized covariance matrices by penalized vector autoregressive models. We consider Lasso-type estimators to reduce the dimensionality and provide strong theoretical guarantees on the forecast capability of our procedure. We show that we can forecast
Suggestions for Realization Rather than Professionalization in Adult Basic Education.
Allen, Fred
1987-01-01
A literature review shows lack of consensus in defining adult education and rejection of the application of the traditional model of professionalism to adult basic education (ABE). Carl Rogers' concept of substituting realization for professionalization, as well as the literature of staff preservice and inservice training, can help practitioners…
Realizing the right to development in Nigeria: an examination of ...
African Journals Online (AJOL)
The United Nations General Assembly has, through several Conventions, emphasized the need for the full realization of the right to development, alongside the rights to food and clean water, the right to shelter and the right to housing. According to the United Nations, if Economic Social and Cultural Rights (ESCR) are ...
Realization of fertility intentions by different time frames.
Dommermuth, Lars; Klobas, Jane; Lappegård, Trude
2015-06-01
This paper focuses on the realization of positive fertility intentions with different time frames. The analyses are based on a unique combination of survey data and information from Norwegian administrative registers on childbearing in the years following the complete selected sample. Guided by the theoretical and empirical framework of the Theory of Planned Behavior (TPB), the results suggest that a fertility intention's time frame is relevant for childbearing behaviour, but the patterns are somewhat different for respondents who were childless at the time of the interview compared to those who already had children. Overall, childless were less likely to realize their fertility intentions than parents. Following the TPB, childless may underestimate the difficulty of acting on their intentions and therefore have more difficulty realizing their intentions, versus parents who take into account their ability to manage another child. The results also show that childless with an immediate fertility intention are more likely to succeed than those with a longer-term intention. Likewise, parents with an immediate fertility intention are more likely to realize their intention during the two first years after the interview, but after four years the childbearing rate was higher among those with longer-term fertility intentions. Copyright © 2015 Elsevier Ltd. All rights reserved.
Realization of an optical interferometer based on holographic optics ...
Indian Academy of Sciences (India)
The proposed interferometer set-up is quite suitable for performing optical test studies on phase (transparent) objects in real-time. Recording schemes for the formation of holographic optical elements and the related technique for the realization of the interferometer set-up along with the experimental results have been ...
Realized range-based estimation of integrated variance
DEFF Research Database (Denmark)
Christensen, Kim; Podolskij, Mark
2007-01-01
solve this problem to get a consistent, mixed normal estimator, irrespective of non-trading effects. This estimator has varying degrees of efficiency over realized variance, depending on how many observations that are used to construct the high-low. The methodology is applied to TAQ data and compared...
The realization of the word in church cathechism
Directory of Open Access Journals (Sweden)
C.J.H. Venter
1988-03-01
Full Text Available The issue that is investigated concerns the dynamic realization processes which occur on the basis of the preaching of the Word of God in church catechism. The study is undertaken by means of a survey and evaluation of relevant data from Dutch, German, American and South African literature. Following that, with the Bible as the primary source, data with regard to the realization of the Bible in the concrete life of the congregation are surveyed and collated. From the analysis of relevant Biblical data the conclusion is reached that the realization, the making real, of the Word in everyday life and existence follows on the act of preaching. This brings us to the awareness that catechetical teaching (that is, preaching of the Word should not stop at the dissemination of knowledge only, but the child should be guided to realise the Word in practical terms in everyday life. Lastly, attention is directed to methods of catechetical teaching, to demands for the construction of the lesson and to the person and the actions of the catechist, and how all these combine to serve the child in the process of realization of the Word in his life.
Computing Realized Compound Yield with a Financial Calculator: A Note
Moy, Ronald L.; Terregrossa, Ralph
2011-01-01
This note points out that realized compound yield (RCY) has a similar concept from capital budgeting; namely, modified internal rate of return. Recognizing this relationship makes it easier to teach the concept and allows students to easily compute RCY using a financial calculator.
Properties of realized variance under alternative sampling schemes
Oomen, R.C.A.
2006-01-01
This paper investigates the statistical properties of the realized variance estimator in the presence of market microstructure noise. Different from the existing literature, the analysis relies on a pure jump process for high frequency security prices and explicitly distinguishes among alternative
Analysis of enabling factors in realizing modularization benefits
DEFF Research Database (Denmark)
Storbjerg, Simon Haahr; Brunø, Thomas Ditlev
2012-01-01
Although modularization is becoming a welldescribed and broadly applied concept, many of today’s firms still struggle to realize the promised benefits of this approach. Managing modularization is a complex matter, and in spite of this, a topic that has received far less attention compared...... with regard to obtaining the full potential of modularization....
Realization of an optical interferometer based on holographic optics ...
Indian Academy of Sciences (India)
The paper describes a simple and cost effective method for the realization of an optical interferometer based on holographic optics, which use minimal bulk optical components. The optical arrangement in the proposed method involves a very simple alignment procedure and inexpensive holographic recording material is ...
Good quality virtual realization of unit disk graphs
Directory of Open Access Journals (Sweden)
Sriram Pemmaraju
2011-08-01
Full Text Available We consider the problem of finding a realization of an n-vertex unit disk graph (UDG expressed in general form, say, as an adjacency matrix. The problem is to construct an embedding of the graph in low-dimensional Euclidean space so that the ratio of the length of the longest edge under the embedding to the length of the shortest non-edge under the embedding is as small as possible; the measure is known as the quality of the realization. Thus, an optimum quality realization has quality between 1/2 and 1. Kuhn et al. gave aO(log3.5 n (loglog n1/2} quality realization that requires solving a linear program with exponentially many constraints by using the ellipsoid algorithm. In this article, we give a combinatorial algorithm that achieves an O(log3 n quality realization of an n-vertex UDG expressed in general form. Thus, not only is our algorithm an improvement, it also bypasses the standard and costly technique of solving a linear program with exponentially many “spreading constraints.” As a side effect of our construction, we get the first constant-factor approximation to the minimum clique partition problem for UDGs expressed in general form. Such a clique partition also represents our key technical contribution. If the embedding is allowed to reside in higher dimensional space, we obtain improved results: a quality-2 embedding in constant dimensional Euclidean space.
Carmeli, Moshe
2000-01-01
This is the only book on the subject of group theory and Einstein's theory of gravitation. It contains an extensive discussion on general relativity from the viewpoint of group theory and gauge fields. It also puts together in one volume many scattered, original works, on the use of group theory in general relativity theory.There are twelve chapters in the book. The first six are devoted to rotation and Lorentz groups, and their representations. They include the spinor representation as well as the infinite-dimensional representations. The other six chapters deal with the application of groups
High-resolution bistable nematic liquid crystal device realized on orientational surface patterns
International Nuclear Information System (INIS)
Kim, Jong-Hyun; Yoneya, Makoto; Yokoyama, Hiroshi
2003-01-01
The four-fold symmetry of a checkerboard-like surface alignment consisted of square domains arrived at the macroscopic orientational bistability of nematic liquid crystals. Switching between the two orientations took place with an appropriate electric field. Here the threshold field of bistable switching decreased as temperature increased, and the light could heat only the selected region in the cell including a light-absorbing medium. Irradiating the laser concurrently with an electric field, we addressed a selected region in the alignment pattern without the disturbance of neighboring regions. Extending this process, we realized an extremely fine bistable device of nematic liquid crystal with a pixel size down to about 2 μm
Realization of collective strong coupling with ion Coulomb crystals in an optical cavity
DEFF Research Database (Denmark)
Herskind, Peter Fønss; Dantan, Aurélien; Marler, Joan
2009-01-01
Cavity quantum electrodynamics (CQED) focuses on understanding the interactions between matter and the electromagnetic field in cavities at the quantum level 1, 2 . In the past years, CQED has attracted attention 3, 4, 5, 6, 7, 8, 9 especially owing to its importance for the field of quantum...... crystal 16 and an optical field. The obtained coherence times are in the millisecond range and indicate that Coulomb crystals positioned inside optical cavities are promising for realizing a variety of quantum-information devices, including quantum repeaters 12 and quantum memories for light 17, 18...... . Moreover, cavity optomechanics 19 using Coulomb crystals might enable the exploration of similar phenomena investigated using more traditional solids, such as micro-mechanical oscillators 20 ....
Tunable defect mode realized by graphene-based photonic crystal
Fu, Jiahui; Chen, Wan; Lv, Bo
2016-04-01
In this literature, we propose an active terahertz 1D photonic crystal, which consists of silicon layers and air layers. A graphene sheet is embedded at the interface between dielectric and air. Tunable photonic band gap is realized by changing the Fermi level of graphene. Transmission Matrix Method is utilized to explain the influence of the graphene layer. We also demonstrate that a dielectric slab attached with a thin sheet made of single-negative metamaterial acts like a pure dielectric slab with a thinner thickness. A tunable blue shift of the band gap can be realized by simply applying different chemical potentials on the graphene sheet. This feature can be utilized for the design of tunable high-gain antenna array and force generator in terahertz band.
Realization problem of multi-layer cellular neural networks.
Ban, Jung-Chao; Chang, Chih-Hung
2015-10-01
This paper investigates whether the output space of a multi-layer cellular neural network can be realized via a single layer cellular neural network in the sense of the existence of finite-to-one map from one output space to the other. Whenever such realization exists, the phenomena exhibited in the output space of the revealed single layer cellular neural network is at most a constant multiple of the phenomena exhibited in the output space of the original multi-layer cellular neural network. Meanwhile, the computation complexity of a single layer system is much less than the complexity of a multi-layer system. Namely, one can trade the precision of the results for the execution time. We remark that a routine extension of the proposed methodology in this paper can be applied to the substitution of hidden spaces although the detailed illustration is omitted. Copyright © 2015 Elsevier Ltd. All rights reserved.
Hardware Realization of Chaos-based Symmetric Video Encryption
Ibrahim, Mohamad A.
2013-05-01
This thesis reports original work on hardware realization of symmetric video encryption using chaos-based continuous systems as pseudo-random number generators. The thesis also presents some of the serious degradations caused by digitally implementing chaotic systems. Subsequently, some techniques to eliminate such defects, including the ultimately adopted scheme are listed and explained in detail. Moreover, the thesis describes original work on the design of an encryption system to encrypt MPEG-2 video streams. Information about the MPEG-2 standard that fits this design context is presented. Then, the security of the proposed system is exhaustively analyzed and the performance is compared with other reported systems, showing superiority in performance and security. The thesis focuses more on the hardware and the circuit aspect of the system’s design. The system is realized on Xilinx Vetrix-4 FPGA with hardware parameters and throughput performance surpassing conventional encryption systems.
Realization of a reference system for the generation radon 222
International Nuclear Information System (INIS)
Guelin, M.
1990-11-01
After some general considerations on radon and its calibration techniques, the methods and technologies developed in order to realize a reference system for the generation of radon 222 are presented. Two original patented techniques have been developed. The former technique deals with the realization of radon 222 solid sources from radium 226 deposit on acrylic fibres. This new technology offers the advantage of very quickly obtaining a constant emission rate near to 100%. The latter technique deals with the standard measurement of radon 222 volumic activity via gamma spectrometry of its short-lived daughters. This new procedure is the only one allowing to relate this measure to gaseous standards. An aeraulic/ventilation circuit makes it possible to calibrate the radon measurement instrumentation within a wide volumic activity range from to 4 to 4 000 Bq/m 3
Realized Jump Risk and Equity Return in China
Directory of Open Access Journals (Sweden)
Guojin Chen
2014-01-01
Full Text Available We utilize the realized jump components to explore a new jump (including nonsystematic jump and systematic jump risk factor model. After estimating daily realized jumps from high-frequency transaction data of the Chinese A-share stocks, we calculate monthly jump size, monthly jump standard deviation, and monthly jump arrival rate and then use those monthly jump factors to explain the return of the following month. Our empirical results show that the jump tail risk can explain the equity return. For the large capital-size stocks, large cap stock portfolios, and index, one-month lagged jump risk factor significantly explains the asset return variation. Our results remain the same even when we add the size and value factors in the robustness tests.
Large quantum Fourier transforms are never exactly realized by braiding conformal blocks
International Nuclear Information System (INIS)
Freedman, Michael H.; Wang, Zhenghan
2007-01-01
Fourier transform is an essential ingredient in Shor's factoring algorithm. In the standard quantum circuit model with the gate set {U(2), controlled-NOT}, the discrete Fourier transforms F N =(ω ij ) NxN , i,j=0,1,...,N-1, ω=e 2πi at ∼sol∼ at N , can be realized exactly by quantum circuits of size O(n 2 ), n=ln N, and so can the discrete sine or cosine transforms. In topological quantum computing, the simplest universal topological quantum computer is based on the Fibonacci (2+1)-topological quantum field theory (TQFT), where the standard quantum circuits are replaced by unitary transformations realized by braiding conformal blocks. We report here that the large Fourier transforms F N and the discrete sine or cosine transforms can never be realized exactly by braiding conformal blocks for a fixed TQFT. It follows that an approximation is unavoidable in the implementation of Fourier transforms by braiding conformal blocks
Realization of the Axion Insulator State in Quantum Anomalous Hall Sandwich Heterostructures
Xiao, Di; Jiang, Jue; Shin, Jae-Ho; Wang, Wenbo; Wang, Fei; Zhao, Yi-Fan; Liu, Chaoxing; Wu, Weida; Chan, Moses H. W.; Samarth, Nitin; Chang, Cui-Zu
2018-02-01
The "magnetoelectric effect" arises from the coupling between magnetic and electric properties in materials. The Z2 invariant of topological insulators (TIs) leads to a quantized version of this phenomenon, known as the topological magnetoelectric (TME) effect. This effect can be realized in a new topological phase called an "axion insulator" whose surface states are all gapped but the interior still obeys time reversal symmetry. We demonstrate such a phase using electrical transport measurements in a quantum anomalous Hall (QAH) sandwich heterostructure, in which two compositionally different magnetic TI layers are separated by an undoped TI layer. Magnetic force microscopy images of the same sample reveal sequential magnetization reversals of the top and bottom layers at different coercive fields, a consequence of the weak interlayer exchange coupling due to the spacer. When the magnetization is antiparallel, both the Hall resistance and Hall conductance show zero plateaus, accompanied by a large longitudinal resistance and vanishing longitudinal conductance, indicating the realization of an axion insulator state. Our findings thus show evidence for a phase of matter distinct from the established QAH state and provide a promising platform for the realization of the TME effect.
ModelSim/Simulink Cosimulation and FPGA Realization of a Multiaxis Motion Controller
Directory of Open Access Journals (Sweden)
Ying-Shieh Kung
2015-01-01
Full Text Available This paper is to implement a multiaxis servo controller and a motion trajectory planning within one chip. At first, SoPC (system on a programmable chip technology which is composed of an Altera FPGA (field programmable gate arrays chip and an embedded soft-core Nios II processor is taken as the development of a multiaxis motion control IC. The multiaxis motion control IC has two modules. The first module is Nios II processor which realizes the motion trajectory planning by software. It includes the step, circular, window, star, and helical motion trajectory. The second module presents a function of the multiaxis position/speed/current controller IP (intellectual property by hardware. And VHDL (VHSIC Hardware Description Language is applied to describe the multiaxis servo controller behavior. Before the FPGA realization, a cosimulation work by ModelSim/Simulink is applied to test the VHDL code. Then, this IP combined by Nios II processor will be downloaded to FPGA. Therefore, a fully digital multiaxis motion controller can be realized by a single FPGA chip. Finally, to verify the effectiveness and correctness of the proposed multiaxis motion control IP, a three-axis motion platform (XYZ table is constructed and some experimental results are presented.
IDC Re-Engineering Phase 2 Iteration E2 Use Case Realizations Version 1.2.
Energy Technology Data Exchange (ETDEWEB)
Hamlet, Benjamin R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Harris, James M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Burns, John F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lober, Randall R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Vickers, James Wallace [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2016-12-01
This document contains 4 use case realizations generated from the model contained in Rational Software Architect. These use case realizations are the current versions of the realizations originally delivered in Elaboration Iteration 2.
IDC Re-Engineering Phase 2 Iteration E3 Use Case Realizations Version 1.2
Energy Technology Data Exchange (ETDEWEB)
Hamlet, Benjamin R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Harris, James M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Burns, John F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2017-01-01
This document contains 4 use case realizations generated from the model contained in Rational Software Architect. These use case realizations are the current versions of the realizations originally delivered in Elaboration Iteration 3.
IDC Re-Engineering Phase 2 Iteration E1 Use Case Realizations version 1.2.
Energy Technology Data Exchange (ETDEWEB)
Hamlet, Benjamin R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Harris, James M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Burns, John F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Montoya, Mark Sinclair [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sandoval, Rudy Daniel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2016-12-01
This document contains 4 use case realizations generated from the model contained in Rational Software Architect. These use case realizations are the current versions of the realizations originally delivered in Elaboration Iteration 1.
Abbas, N; Mansoor, M M; Shad, S A; Pathan, A K; Waheed, A; Ejaz, M; Razaq, M; Zulfiqar, M A
2014-12-01
The common green lacewing Chrysoperla carnea is a key biological control agent employed in integrated pest management (IPM) programs for managing various insect pests. Spinosad is used for the management of pests in ornamental plants, fruit trees, vegetable and field crops all over the world, including Pakistan. A field-collected population of C. carnea was selected with spinosad and fitness costs and realized heritability were investigated. After selection for five generations, C. carnea developed 12.65- and 73.37-fold resistance to spinosad compared to the field and UNSEL populations. The resistant population had a relative fitness of 1.47, with substantially higher emergence rate of healthy adults, fecundity and hatchability and shorter larval duration, pupal duration, and development time as compared to a susceptible laboratory population. Mean relative growth rate of larvae, intrinsic rate of natural population increase and biotic potential was higher for the spinosad-selected population compared to the susceptible laboratory population. Chrysoperla species are known to show resistance to insecticides which makes the predator compatible with most IPM systems. The realized heritability (h 2) value of spinosad resistance was 0.37 in spinosad-selected population of C. carnea.
Interests, Preferences, and the Realization of Goals: Nigeria and ...
African Journals Online (AJOL)
Mrs Afam
An International Multidisciplinary Journal, Ethiopia. Vol. 8(4), Serial No. 35, September, 2014:122-132. ISSN 1994-9057 (Print). ISSN 2070--0083 (Online). DOI: http://dx.doi.org/10.4314/afrrev.v8i4.10. Interests, Preferences, and the Realization of Goals: Nigeria and Vision 20:2020 (A follow-up to Eddy Erhagbe's Position). 1.
Open Chemistry: Realizing Open Data, Open Standards, and Open Source
Hanwell, Marcus; Harris, Chris; Lonie, David; Lutz, Kyle; Cole, David
2012-01-01
The Blue Obelisk has brought together the computational chemistry community and those who are passionate about Open Chemistry and realizing the promise of Open Data, Open Standards, and Open Software (ODOSOS); the three pillars the group promotes. We will present current work that has taken place over the past five years, which is inspired by these pillars, and present plans for future work.The group is actively engaged in multiple open source projects that rely on and promote open standards ...
Hardware realization of chaos based block cipher for image encryption
Barakat, Mohamed L.
2011-12-01
Unlike stream ciphers, block ciphers are very essential for parallel processing applications. In this paper, the first hardware realization of chaotic-based block cipher is proposed for image encryption applications. The proposed system is tested for known cryptanalysis attacks and for different block sizes. When implemented on Virtex-IV, system performance showed high throughput and utilized small area. Passing successfully in all tests, our system proved to be secure with all block sizes. © 2011 IEEE.
Wigner crystals: New realizations of an old idea
Directory of Open Access Journals (Sweden)
Sólyom J.
2014-01-01
Full Text Available In this review, after a brief discussion of Wigner’s ideas about the localization of electrons due to Coulomb interaction in a low-density electron system with neutralizing background and the formation of a periodic array, we present the various possibilities to realize Wigner crystals: on the surface of liquid helium, in semiconductor heterostructures, in graphene, in 1D systems and the analogous crystalline states in dusty plasma or in the assembly of trapped ions.
Manipulating electromagnetic waves with metamaterials: Concept and microwave realizations
International Nuclear Information System (INIS)
He Qiong; Xiao Shi-Yi; Li Xin; Song Zheng-Yong; Sun Wu-Jiong; Zhou Lei; Sun Shu-Lin
2014-01-01
Our recent efforts in manipulating electromagnetic (EM) waves using metamaterials (MTMs) are reviewed with emphasis on 1) manipulating wave polarization and transporting properties using homogeneous MTMs, 2) manipulating surface-wave properties using plasmonic MTMs, and 3) bridging propagating and surface waves using inhomogeneous meta-surfaces. For all these topics, we first illustrate the physical concepts and then present several typical practical realizations and applications in the microwave regime. (topical review - plasmonics and metamaterials)
Realization of the revival of silenced echo (ROSE) quantum memory scheme in orthogonal geometry
Minnegaliev, M. M.; Gerasimov, K. I.; Urmancheev, R. V.; Moiseev, S. A.; Chanelière, T.; Louchet-Chauvet, A.
2018-02-01
We demonstrated quantum memory scheme on revival of silenced echo in orthogonal geometry in Tm3+: Y3Al5O12 crystal. The retrieval efficiency of ˜14% was demonstrated with the 36 µs storage time. In this scheme for the first time we also implemented a suppression of the revived echo signal by applying an external electric field and the echo signal has been recovered on demand if we then applied a second electric pulse with opposite polarity. This technique opens the possibilities for realizing addressing in multi-qubit quantum memory in Tm3+: Y3Al5O12 crystal.
Circuit QED scheme for realization of the Lipkin-Meshkov-Glick model
Larson, Jonas
2010-01-01
We propose a scheme in which the Lipkin-Meshkov-Glick model is realized within a circuit QED system. An array of N superconducting qubits interacts with a driven cavity mode. In the dispersive regime, the cavity mode is adiabatically eliminated generating an effective model for the qubits alone. The characteristic long-range order of the Lipkin-Meshkov-Glick model is here mediated by the cavity field. For a closed qubit system, the inherent second order phase transition of the qubits is refle...
Realization of Anisotropic Diamagnetic Kepler Problem in a Solid State Environment
International Nuclear Information System (INIS)
Chen Zhanghai; Zhou Weihang; Zhang Bo; Yu, C. H.; Zhu Jingbing; Lu Wei; Shen, S. C.
2009-01-01
The anisotropic diamagnetic Kepler problem (ADKP) is realized experimentally by the orbital electrons of a P donor in Si under magnetic fields. The interference of electron wave packets which leads to quasi-Landau resonances (QLR) were observed. Applying the closed-orbit theory to an anisotropic solid state environment, we have identified orbits responsible for the QLR manifesting the quantum chaotic behavior in Rydberg atoms. The excellent consistency between the measured spectra and theoretical calculation provides unambiguous evidence of quantum chaotic dynamics of electrons in the ADKP.
Hardware and software realization of EDSD for acupuncture research and practice.
Fico, T; Duchon, F; Dubravsky, J
2014-07-01
Traditional acupuncture as a diagnostic and therapeutic method has been known in China for more than 3000 years. Electrodermal screening tests (EDSTs) and electrodermal screening devices (EDSDs) that are based on the knowledge derived from traditional Chinese medicine appeared in the 1950s. This article deals with design, development and realization of such a device. The design considers the principles of two widely used EDSTs and modern trends in the field of electronics and data management. A computer program with simple user interface that provides graphic evaluation and intercomparison of measured data are presented. The designed system is suitable not only for acupuncture research but also for ordinary acupuncture diagnostics.
Nonlinear symmetry realizations and the generalized CP sup(n-1) model
International Nuclear Information System (INIS)
Santos, T.A.
1982-01-01
The genralized CP sup(n-1) model having U(p) as Gauge group in the two-dimension Euclidean space in the several existing formulations is presented. Such a model is described as a nonlinear symmetry realization which becames linear when restricted to a determined sub-groups treating therefore of fields which have values in the quocient space G/H. Classical instanton and meron solutions for this model are presented and the existence of a mechanism to generate a family of non auto-dual solutions with finite action, taking as starting point the instanton solutions, is demonstrated. (L.C.) [pt
Directory of Open Access Journals (Sweden)
U. A. Sychou
2014-01-01
Full Text Available In this article, the problem of the practical realization of nonlinear systems with chaotic dynam-ics for targeted generation of chaotic sequences in digital devices is considered. The possible applica-tion in this task with using fixed-point arithmetic to ensure the identity of the obtained results on dif-ferent hardware and software platforms is studied. The implementation of logistic mapping is described; carry out the analysis of the results. This article proposes using the obtained results for the various tasks of the field of mobile robotics.
Realization of Copper Melting Point for Thermocouple Calibrations
Directory of Open Access Journals (Sweden)
Y. A. ABDELAZIZ
2011-08-01
Full Text Available Although the temperature stability and uncertainty of the freezing plateau is better than that of the melting plateau in most of the thermometry fixed points, but realization of melting plateaus are easier than that of freezing plateaus for metal fixed points. It will be convenient if the melting points can be used instead of the freezing points in calibration of standard noble metal thermocouples because of easier realization and longer plateau duration of melting plateaus. In this work a comparison between the melting and freezing points of copper (Cu was carried out using standard noble metal thermocouples. Platinum - platinum 10 % rhodium (type S, platinum – 30 % rhodium / platinum 6 % rhodium (type B and platinum - palladium (Pt/Pd thermocouples are used in this study. Uncertainty budget analysis of the melting points and freezing points is presented. The experimental results show that it is possible to replace the freezing point with the melting point of copper cell in the calibration of standard noble metal thermocouples in secondary-level laboratories if the optimal methods of realization of melting points are used.
Tunable defect mode realized by graphene-based photonic crystal
Energy Technology Data Exchange (ETDEWEB)
Fu, Jiahui; Chen, Wan, E-mail: dhtyyobdc@126.com; Lv, Bo
2016-04-29
In this literature, we propose an active terahertz 1D photonic crystal, which consists of silicon layers and air layers. A graphene sheet is embedded at the interface between dielectric and air. Tunable photonic band gap is realized by changing the Fermi level of graphene. Transmission Matrix Method is utilized to explain the influence of the graphene layer. We also demonstrate that a dielectric slab attached with a thin sheet made of single-negative metamaterial acts like a pure dielectric slab with a thinner thickness. A tunable blue shift of the band gap can be realized by simply applying different chemical potentials on the graphene sheet. This feature can be utilized for the design of tunable high-gain antenna array and force generator in terahertz band. - Highlights: • A novel PhC embedded with grapheme sheets is presented, tunable defect is realized. • The mechanism of the tunable defect is explained using the change of equivalent thickness. • The electromagnetic force of a slab is calculated, which indicates the structure can serve as a tunable force generator.
Experimental realization of an optical second with strontium lattice clocks.
Le Targat, R; Lorini, L; Le Coq, Y; Zawada, M; Guéna, J; Abgrall, M; Gurov, M; Rosenbusch, P; Rovera, D G; Nagórny, B; Gartman, R; Westergaard, P G; Tobar, M E; Lours, M; Santarelli, G; Clairon, A; Bize, S; Laurent, P; Lemonde, P; Lodewyck, J
2013-01-01
Progress in realizing the SI second had multiple technological impacts and enabled further constraint of theoretical models in fundamental physics. Caesium microwave fountains, realizing best the second according to its current definition with a relative uncertainty of 2-4 × 10(-16), have already been overtaken by atomic clocks referenced to an optical transition, which are both more stable and more accurate. Here we present an important step in the direction of a possible new definition of the second. Our system of five clocks connects with an unprecedented consistency the optical and the microwave worlds. For the first time, two state-of-the-art strontium optical lattice clocks are proven to agree within their accuracy budget, with a total uncertainty of 1.5 × 10(-16). Their comparison with three independent caesium fountains shows a degree of accuracy now only limited by the best realizations of the microwave-defined second, at the level of 3.1 × 10(-16).
The Realized Hierarchical Archimedean Copula in Risk Modelling
Directory of Open Access Journals (Sweden)
Ostap Okhrin
2017-06-01
Full Text Available This paper introduces the concept of the realized hierarchical Archimedean copula (rHAC. The proposed approach inherits the ability of the copula to capture the dependencies among financial time series, and combines it with additional information contained in high-frequency data. The considered model does not suffer from the curse of dimensionality, and is able to accurately predict high-dimensional distributions. This flexibility is obtained by using a hierarchical structure in the copula. The time variability of the model is provided by daily forecasts of the realized correlation matrix, which is used to estimate the structure and the parameters of the rHAC. Extensive simulation studies show the validity of the estimator based on this realized correlation matrix, and its performance, in comparison to the benchmark models. The application of the estimator to one-day-ahead Value at Risk (VaR prediction using high-frequency data exhibits good forecasting properties for a multivariate portfolio.
Stress-energy tensor of quantized massive fields in static wormhole spacetimes
Kocuper, Ewa; Matyjasek, Jerzy; Zwierzchowska, Kasia
2017-11-01
In order to be traversable, the static Lorentzian wormhole must be made out of some exotic matter that violates the weak energy condition. The quantized fields are the natural candidates as their stress-energy tensor, in many cases, possesses desired properties. In this paper we construct and examine the stress-energy tensor of the quantized massive scalar, spinor and vector fields in six static wormhole spacetimes. We find that in all considered cases the quantum fields violate the Morris-Thorne conditions and do not have the form necessary to support the wormhole throat. This is in concord with the previous results and indicates that the massive quantum fields make the wormholes less operable.
A Dyson realization and a Holstein-Primakoff realization for the quantum superalgebra $U_q[gl(n/m)]$
Palev, T. D.
1998-01-01
The Holstein-Primakoff and the Dyson realizations of the Lie superalgebra $gl(n/m)$ are generalized to the class of the quantum superalgebras $U_q[gl(n/m)]$ for any $n$ and $m$. It is shown how the elements of $U_q[gl(n/m)]$ can be expressed via $n-1$ pairs of Bose creation and annihilation operators and $m$ pairs of Fermi creation and annihilation operators.
International Nuclear Information System (INIS)
Peter, I. J.
1995-06-01
The work deals with space-times with fixed background metric. The topics were arranged in a straight course, the first chapter collects basic facts on Lorentzian manifolds as time-orientability, causal structure, ... Further free neutral scalar fields and spinor fields described by the Klein-Gordon equation resp. the Dirac equation are dealt with. Having in mind the construction of the Weyl algebra and the Fermi algebra in the second chapter, it was put emphasis on the structure of the spaces of solutions of these equations: In the first case the space of solutions is a symplectic vector space in a canonical manner, in the second case a Hilbert space. It was made some effort to stay as general as possible. Most of the material in the second chapter already exists for several years, but it is largely scattered over various journal articles. In the third chapter the construction of a vacuum on the special example of deSitter universe is described. A close investigation of a recent work by J. Bros and U. Moschella made it possible to refine a result concerning temperature felt by an accelerated observer in deSitter space. The last part of this thesis is concerned with vacua for spinor fields on the two-dimensional deSitter universe. A procedure introduced by R. Haag, H. Narnhofer and U. Stein for four dimensional space-times does not seem to work in two dimensions. (author)
Tachyons and virtual fields for elementary particles in strong interactions. Part 1
International Nuclear Information System (INIS)
Van der Spuy, E.
1978-01-01
An infinite component free field is constructed and carries an infinite tower of unstable selfcompounds which is defined by a mass-squared trajectory. The field transforms locally under the Poincare group, being a direct sum of spinor representations. The norm or propagator of the field can be written as an infinite partial series (in spin j) of contributions of positive definite metric, which permits transformation to a Regge pole plus background contribution. The Regge pole dominates in the relativistic domain p→infinity. The associated continuation to complex j values introduces an indefinite metric into the propagator and has associated oscillatory characteristic functions of the spinor representation. The constraint on the mass-squared function permits the propogator to be written in terms of partial propagators such that the resonances appear in the correct position on the second z sheet and the Regge poles in the correct Regge j-quadrants. The partial propagator can be written in a TCP invariant form in terms of a spectral function determined by the dispersion integral for a particular condition on the mass-squared trajectory and involving continua of the real mass-squared variable r (r>=4m 2 0 and r 0 is the stable mass corresponding to spin j=0). This allows the complete infinite component free field corresponding to the real mass-squared and spin spectrum to be constructed in such a way that it transforms locally under Lorentz transformatons and has a propagator which has the right resonances and motion of Regge poles. Since there is one mass spectral function, the field should be considered in toto and as a fully virtual field, and furthermore as a possible solution of nonlinear field equation of motion. The tachyonic field component r [af
CT use for nasopharingeal molds realization in endocavitary brachytherapy
International Nuclear Information System (INIS)
Lopez, J. Torrecilla; Crispin, V.; Chust, M.; Guinot, J.; Arribas, L.; Mengual, J.; Carrasco, P.; Miragall, E.; Hernandez, A.; Guardino, C.; Carrascosa, M.; Cardenal, R.; Casana, M.; Prats, C.
1996-01-01
Purpose: We present the following procedure for the making of individual molds with dental silicone for endocavitary brachytherapy of nasopharingeal cancer aided by CT scan. Procedure: Head immobilization during the realization of nasopharynx CT. Planification of treatment using these CT images, to determine the optimum position of radioactive sources. Printing on paper CT images with the nasopharynx contoured walls and the radioactive sources position. Realization of the mold in plastiline with the aid of the cuts of printer paper cut out with the nasopharynx form. Obtaining of the negative of the mold of plastiline by means of the use of alginate. Placement of two number 20 rectal rigid catheters with metal malleable bars inside them, in order to give them an adequate form in relation to the previous carried out planning. Filling in of alginato negative, where rectal catheters were placed, with Provil MCD Bayer Dental, a silicone based material for precision impression. We recommend to crossing the catheters' end with a number 2 silk thread to secure the catheter. An end of the silk thread is left outside the mold in order to help the extraction at the end of application. We advise to carry out a neuroleptic anaesthesia for its insertion, for the purpose of achieving a soft palate suitable relaxation. It makes the insertion easier. Repeat CT with the mold and phantoms in position to know a definitive dose distribution calculation. Conclusion: This method avoids the necessity of general anaesthesia in the realization of individual molds of nasopharyx for endocavitary brachytherapy and it improves the implant dosimetry
A first theoretical realization of honeycomb topological magnon insulator
Owerre, S. A.
2016-09-01
It has been recently shown that in the Heisenberg (anti)ferromagnet on the honeycomb lattice, the magnons (spin wave quasipacticles) realize a massless two-dimensional (2D) Dirac-like Hamiltonian. It was shown that the Dirac magnon Hamiltonian preserves time-reversal symmetry defined with the sublattice pseudo spins and the Dirac points are robust against magnon-magnon interactions. The Dirac points also occur at nonzero energy. In this paper, we propose a simple realization of nontrivial topology (magnon edge states) in this system. We show that the Dirac points are gapped when the inversion symmetry of the lattice is broken by introducing a next-nearest neighbour Dzyaloshinskii-Moriya (DM) interaction. Thus, the system realizes magnon edge states similar to the Haldane model for quantum anomalous Hall effect in electronic systems. However, in contrast to electronic spin current where dissipation can be very large due to Ohmic heating, noninteracting topological magnons can propagate for a long time without dissipation as magnons are uncharged particles. We observe the same magnon edge states for the XY model on the honeycomb lattice. Remarkably, in this case the model maps to interacting hardcore bosons on the honeycomb lattice. Quantum magnetic systems with nontrivial magnon edge states are called topological magnon insulators. They have been studied theoretically on the kagome lattice and recently observed experimentally on the kagome magnet Cu(1-3, bdc) with three magnon bulk bands. Our results for the honeycomb lattice suggests an experimental procedure to search for honeycomb topological magnon insulators within a class of 2D quantum magnets and ultracold atoms trapped in honeycomb optical lattices. In 3D lattices, Dirac and Weyl points were recently studied theoretically, however, the criteria that give rise to them were not well-understood. We argue that the low-energy Hamiltonian near the Weyl points should break time-reversal symmetry of the pseudo spins
Design and Realization of Laser Diode Power Supply
Directory of Open Access Journals (Sweden)
Jiri Svarny
2008-01-01
Full Text Available Under the terms of development of specialized system for transmissions of analogue high frequency signals by means of optical fibres, the source of coherent infrared radiation has been designed and manufactured. The source has to excite Mach–Zehnder type external intensity electro-optical modulator. That is why the generated radiation has to meet certain requirements. Rigorously constant optical power and wavelength as well as linear polarisation of the radiation have tobe reached. The parameters must be time stable and independent on external influences – especially temperature changes.The article is focused on structure of the realized appliance and submits achieved results.
Geometric Realizations of Bi-Hamiltonian Completely Integrable Systems
Directory of Open Access Journals (Sweden)
Gloria Marí Beffa
2008-03-01
Full Text Available In this paper we present an overview of the connection between completely integrable systems and the background geometry of the flow. This relation is better seen when using a group-based concept of moving frame introduced by Fels and Olver in [Acta Appl. Math. 51 (1998, 161-213; 55 (1999, 127-208]. The paper discusses the close connection between different types of geometries and the type of equations they realize. In particular, we describe the direct relation between symmetric spaces and equations of KdV-type, and the possible geometric origins of this connection.
Realization of an all optical exciton-polariton router
International Nuclear Information System (INIS)
Marsault, Félix; Nguyen, Hai Son; Tanese, Dimitrii; Lemaître, Aristide; Galopin, Elisabeth; Sagnes, Isabelle; Amo, Alberto; Bloch, Jacqueline
2015-01-01
We report on the experimental realization of an all optical router for exciton-polaritons. This device is based on the design proposed by Flayac and Savenko [Appl. Phys. Lett. 103, 201105 (2013)], in which a zero-dimensional island is connected through tunnel barriers to two periodically modulated wires of different periods. Selective transmission of polaritons injected in the island, into either of the two wires, is achieved by tuning the energy of the island state across the band structure of the modulated wires. We demonstrate routing of ps polariton pulses using an optical control beam which controls the energy of the island quantum states, thanks to polariton-exciton interactions
Superworld volume dynamics of super branes from nonlinear realizations
International Nuclear Information System (INIS)
Bellucci, S.; Ivanov, E.; Krivonos, S.
2000-01-01
Based on the concept of the partial breaking of global supersymmetry (PBGS), it has been derived the world volume superfield equations of motion for N=1, D=4 supermembrane, as well as for the space-time filling D2- and D3-branes, from nonlinear realizations of the corresponding supersymmetries. It has been argued that it is of no need to take care of the relevant automorphism groups when being interested in the dynamical equations. This essentially facilitates computations. As a by-product, it has been obtained a new polynomial representation for the d=3,4 Born-Infeld equations, with merely a cubic nonlinearity
Realization of a complementary medium using dielectric photonic crystals.
Xu, Tao; Fang, Anan; Jia, Ziyuan; Ji, Liyu; Hang, Zhi Hong
2017-12-01
By exploiting the scaling invariance of photonic band diagrams, a complementary photonic crystal slab structure is realized by stacking two uniformly scaled double-zero-index dielectric photonic crystal slabs together. The space cancellation effect in complementary photonic crystals is demonstrated in both numerical simulations and microwave experiments. The refractive index dispersion of double-zero-index dielectric photonic crystal is experimentally measured. Using pure dielectrics, our photonic crystal structure will be an ideal platform to explore various intriguing properties related to a complementary medium.
Nonlinear realization of supersymmetric AdS space isometries
International Nuclear Information System (INIS)
Clark, T. E.; Love, S. T.
2006-01-01
The isometries of AdS 5 space and supersymmetric AdS 5 xS 1 space are nonlinearly realized on four-dimensional Minkowski space. The resultant effective actions in terms of the Nambu-Goldstone modes are constructed. The dilatonic mode governing the motion of the Minkowski space probe brane into the covolume of supersymmetric AdS 5 space is found to be unstable and the bulk of the AdS 5 space is unable to sustain the brane. No such instability appears in the nonsupersymmetric case
Conception of personal career as a self-realization project
Tarasova, Julija
2017-01-01
SUMMARY Conception of personal career as a self-realization project. Bachelor work. Relevance: Nowadays career is an important aspect in an individual’s life where the main author of the script, the director and creator is the person who takes responsibility for his/her own life. Modern career management is a life long process, which is more like a self monitored project based on self realisation. A successful career in project management is not only about an individual’s personal qualities, ...
Christiansen filter realized by an odd smooth cylindrical lens.
Li, Jian; Goddard, N; Xie, Kang
2010-01-01
The Christiansen filter that is realized by odd smooth cylindrical lenses is analyzed in detail. Several popular filtering functions are discussed. The corresponding lens profile functions are obtained by an inverse scattering theory, which enables the filter to synthesize a desired prescribed response function. This kind of Christiansen filter has a passband narrower than that of the traditional Christiansen filter. Three Christiansen filters centered at 545 nm with full width at half-maximum of 2 nm are synthesized, and the approach to a better suppression of halos from the main transmission peak of the filters is presented in a systematic way.
Amorphous graphene: a realization of Zachariasen’s glass
International Nuclear Information System (INIS)
Kumar, Avishek; Thorpe, M F; Wilson, Mark
2012-01-01
Amorphous graphene is a realization of a two-dimensional Zachariasen glass as first proposed 80 years ago. Planar continuous random networks of this archetypal two-dimensional network are generated by two complementary simulation methods. In the first, a Monte Carlo bond switching algorithm is employed to systematically amorphize a crystalline graphene sheet. In the second, molecular dynamics simulations are utilized to quench from the high temperature liquid state. The two approaches lead to similar results as detailed here, through the pair distribution function and the associated diffraction pattern. Details of the structure, including ring statistics and angular distortions, are shown to be sensitive to preparation conditions, and await experimental confirmation.
Confidence Intervals from Realizations of Simulated Nuclear Data
Energy Technology Data Exchange (ETDEWEB)
Younes, W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ratkiewicz, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ressler, J. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2017-09-28
Various statistical techniques are discussed that can be used to assign a level of confidence in the prediction of models that depend on input data with known uncertainties and correlations. The particular techniques reviewed in this paper are: 1) random realizations of the input data using Monte-Carlo methods, 2) the construction of confidence intervals to assess the reliability of model predictions, and 3) resampling techniques to impose statistical constraints on the input data based on additional information. These techniques are illustrated with a calculation of the keff value, based on the ^{235}U(n, f) and ^{239}Pu (n, f) cross sections.
Direct-write graded index materials realized in protein hydrogels
Kaehr, Bryan; Scrymgeour, David A.
2016-09-01
The ability to create optical materials with arbitrary index distributions would prove transformative for optics design and applications. However, current fabrication techniques for graded index (GRIN) materials rely on diffusion profiles and therefore are unable to realize arbitrary distribution GRIN design. Here, we demonstrate the laser direct writing of graded index structures in protein-based hydrogels using multiphoton lithography. We show index changes spanning a range of 10-2, which is comparable with laser densified glass and polymer systems. Further, we demonstrate the conversion of these written density variation structures into SiO2, opening up the possibility of transforming GRIN hydrogels to a wide range of material systems.
Practical realization of a microwave Bessel beam launcher
Manzhura, Oksana
2011-08-01
An experimental setup is realized to practically generate Bessel beams in the microwave regime. The setup, which consists of a series of circular loop antennas inserted coaxially inside a circular metallic waveguide, excites the waveguide\\'s transverse-electric modes such that their superposition forms a Bessel beam at the open-end of the waveguide. The excitation currents are calculated from the needed excitation coefficients of each guided mode, which, in turn, are calculated from the modal decomposition of the beam. The efficiency of the setup is evaluated and the obtained experimental results are compared to the theoretical estimates. © 2011 IEEE.
International Nuclear Information System (INIS)
Lee, Eun-Kyu; Kim, Jong-Hyun
2008-01-01
We have observed the alignment property and switching behaviour of nematic liquid crystals (NLCs) on orientation patterns that were realized on a photo-active alignment layer by using interferring beams of two coherent laser lights. Linearly polarized light orients the liquid crystals in a direction perpendicular to the polarization and the interferring laser light induced a one-dimensional periodic texture following the interference pattern. Using double irradiation, in which the direction of the second irradiation was rotated by 90 0 to the first irradiation, we constructed a quasi-four-fold symmetric orientation pattern. The NLCs exhibited bistability in two average directions of polarization of the laser light, and they stably switched between the two directions by the in-plane electric field. Furthermore, the NLCs indicated the capability of continuous and memorized switching with a changing electric field on the orientation pattern
Realizing a new paradigm in radiation therapy treatment planning
International Nuclear Information System (INIS)
Ziegenhein, Peter
2013-01-01
This thesis investigates the feasibility of a new IMRT planning paradigm called Interactive Dose Shaping (IDS). The IDS paradigm enables the therapist to directly impose local dose features into the therapy plan. In contrast to the conventional IMRT planning approach, IDS does not employ an objective function to drive an iterative optimization procedure. In the first part of this work, the conventional IMRT plan optimization method is investigated. Concepts for a near-optimal implementation of the planning problem are provided. The second part of this work introduces the IDS concept. It is designed to overcome clinical drawbacks of the conventional method on the one hand and to provide interactive planning strategies which exploit the full potential of modern high-performance computer hardware on the other hand. The realization of the IDS concept consists of three main parts. (1)A two-step Dose Variation and Recovery (DVR) strategy which imposes localized plan features and recovers for unintentional plan modifications elsewhere. (2)A new dose calculation method (3)The design of an IDS planning framework which provides a powerful graphical user interface. It could be shown that the IDS paradigm is able to reproduce conventionally optimized therapy plans and that the IDS concepts can be realized in real-time.
Practical Quantum Realization of the Ampere from the Elementary Charge
Directory of Open Access Journals (Sweden)
J. Brun-Picard
2016-12-01
Full Text Available One major change of the future revision of the International System of Units is a new definition of the ampere based on the elementary charge e. Replacing the former definition based on Ampère’s force law will allow one to fully benefit from quantum physics to realize the ampere. However, a quantum realization of the ampere from e, accurate to within 10^{-8} in relative value and fulfilling traceability needs, is still missing despite the many efforts made for the development of single-electron tunneling devices. Starting again with Ohm’s law, applied here in a quantum circuit combining the quantum Hall resistance and Josephson voltage standards with a superconducting cryogenic amplifier, we report on a practical and universal programmable quantum current generator. We demonstrate that currents generated in the milliampere range are accurately quantized in terms of ef_{J} (f_{J} is the Josephson frequency with measurement uncertainty of 10^{-8}. This new quantum current source, which is able to deliver such accurate currents down to the microampere range, can greatly improve the current measurement traceability, as demonstrated with the calibrations of digital ammeters. In addition, it opens the way to further developments in metrology and in fundamental physics, such as a quantum multimeter or new accurate comparisons to single-electron pumps.
Binary higher order neural networks for realizing Boolean functions.
Zhang, Chao; Yang, Jie; Wu, Wei
2011-05-01
In order to more efficiently realize Boolean functions by using neural networks, we propose a binary product-unit neural network (BPUNN) and a binary π-ς neural network (BPSNN). The network weights can be determined by one-step training. It is shown that the addition " σ," the multiplication " π," and two kinds of special weighting operations in BPUNN and BPSNN can implement the logical operators " ∨," " ∧," and " ¬" on Boolean algebra 〈Z(2),∨,∧,¬,0,1〉 (Z(2)={0,1}), respectively. The proposed two neural networks enjoy the following advantages over the existing networks: 1) for a complete truth table of N variables with both truth and false assignments, the corresponding Boolean function can be realized by accordingly choosing a BPUNN or a BPSNN such that at most 2(N-1) hidden nodes are needed, while O(2(N)), precisely 2(N) or at most 2(N), hidden nodes are needed by existing networks; 2) a new network BPUPS based on a collaboration of BPUNN and BPSNN can be defined to deal with incomplete truth tables, while the existing networks can only deal with complete truth tables; and 3) the values of the weights are all simply -1 or 1, while the weights of all the existing networks are real numbers. Supporting numerical experiments are provided as well. Finally, we present the risk bounds of BPUNN, BPSNN, and BPUPS, and then analyze their probably approximately correct learnability.
Performance optimization of queueing systems with perturbation realization
Xia, Li
2012-04-01
After the intensive studies of queueing theory in the past decades, many excellent results in performance analysis have been obtained, and successful examples abound. However, exploring special features of queueing systems directly in performance optimization still seems to be a territory not very well cultivated. Recent progresses of perturbation analysis (PA) and sensitivity-based optimization provide a new perspective of performance optimization of queueing systems. PA utilizes the structural information of queueing systems to efficiently extract the performance sensitivity information from a sample path of system. This paper gives a brief review of PA and performance optimization of queueing systems, focusing on a fundamental concept called perturbation realization factors, which captures the special dynamic feature of a queueing system. With the perturbation realization factors as building blocks, the performance derivative formula and performance difference formula can be obtained. With performance derivatives, gradient-based optimization can be derived, while with performance difference, policy iteration and optimality equations can be derived. These two fundamental formulas provide a foundation for performance optimization of queueing systems from a sensitivity-based point of view. We hope this survey may provide some inspirations on this promising research topic. © 2011 Elsevier B.V. All rights reserved.
Kullie, O; Zhang, H; Kolb, J; Kolb, D
2006-12-28
In previous work the authors have presented a highly accurate two-spinor fully relativistic solution of the two-center Coulomb problem utilizing the finite-element method (FEM) and furthermore developed a relativistic minimax two-spinor linear combination of atomic orbitals (LCAO). In the present paper the authors present Dirac-Fock-Slater (DFS-) density functional calculations for two-atomic molecules up to super heavy systems using the fully nonlinear minimax FEM and the minimax LCAO in its linearized approximation (linear approximation to relativistic minimax). The FEM gives highly accurate benchmark results for the DFS functional. Especially considering molecules with up to super heavy atoms such as UubO and Rg2, the authors found that LCAO fails to give the correct systematic trends. The accurate FEM results shed a new light on the quality of the DFS-density functional.
Spin tunnelling dynamics for spin-1 Bose-Einstein condensates in a swept magnetic field
International Nuclear Information System (INIS)
Wang Guanfang; Fu Libin; Liu Jie
2008-01-01
We investigate the spin tunnelling of spin-1 Bose-Einstein condensates in a linearly swept magnetic field with a mean-field treatment. We focus on the two typical alkali Bose atoms 87 Rb and 23 Na condensates and study their tunnelling dynamics according to the sweep rates of the external magnetic fields. In the adiabatic (i.e. slowly sweeping) and sudden (i.e. fast sweeping) limits, no tunnelling is observed. For the case of moderate sweep rates, the tunnelling dynamics is found to be very sensitive to the sweep rates, so the plots of tunnelling probability versus sweep rate only become resolvable at a resolution of 10 -4 G s -1 . Moreover, a conserved quantity standing for the magnetization in experiments is found to affect dramatically the dynamics of the spin tunnelling. Theoretically we have given a complete interpretation of the above findings, and our studies could stimulate the experimental study of spinor Bose-Einstein condensates
Gravitational Field effects on the Decoherence Process and the Quantum Speed Limit.
Dehdashti, Sh; Avazzadeh, Z; Xu, Z; Shen, J Q; Mirza, B; Wang, H
2017-11-08
In this paper we use spinor transformations under local Lorentz transformations to investigate the curvature effect on the quantum-to-classical transition, described in terms of the decoherence process and of the quantum speed limit. We find that gravitational fields (introduced adopting the Schwarzschild and anti-de Sitter geometries) affect both the decoherence process and the quantum speed limit of a quantum particle with spin-1/2. In addition, as a tangible example, we study the effect of the Earth's gravitational field, characterized by the Rindler space-time, on the same particle. We find that the effect of the Earth's gravitational field on the decoherence process and quantum speed limit is very small, except when the mean speed of the quantum particle is comparable to the speed of light.
Maxwell, Yang-Mills, Weyl and eikonal fields defined by any null shear-free congruence
Kassandrov, Vladimir V.; Rizcallah, Joseph A.
We show that (specifically scaled) equations of shear-free null geodesic congruences on the Minkowski space-time possess intrinsic self-dual, restricted gauge and algebraic structures. The complex eikonal, Weyl 2-spinor, SL(2, ℂ) Yang-Mills and complex Maxwell fields, the latter produced by integer-valued electric charges (“elementary” for the Kerr-like congruences), can all be explicitly associated with any shear-free null geodesic congruence. Using twistor variables, we derive the general solution of the equations of the shear-free null geodesic congruence (as a modification of the Kerr theorem) and analyze the corresponding “particle-like” field distributions, with bounded singularities of the associated physical fields. These can be obtained in a straightforward algebraic way and exhibit nontrivial collective dynamics simulating physical interactions.
Yang-Mills Field from Quaternion Space Geometry, and its Klein-Gordon Representation
Directory of Open Access Journals (Sweden)
Yefremov A.
2007-07-01
Full Text Available Analysis of covariant derivatives of vectors in quaternion (Q- spaces performed using Q-unit spinor-splitting technique and use of SL(2C-invariance of quaternion multiplication reveals close connexion of Q-geometry objects and Yang-Mills (YM field principle characteristics. In particular, it is shown that Q-connexion (with quaternion non-metricity and related curvature of 4 dimensional (4D space-times with 3D Q-space sections are formally equivalent to respectively YM-field potential and strength, traditionally emerging from the minimal action assumption. Plausible links between YM field equation and Klein-Gordon equation, in particular via its known isomorphism with Duffin-Kemmer equation, are also discussed.
A Chargeless Complex Vector Matter Field in Supersymmetric Scenario
Directory of Open Access Journals (Sweden)
L. P. Colatto
2015-01-01
Full Text Available We construct and study a formulation of a chargeless complex vector matter field in a supersymmetric framework. To this aim we combine two nochiral scalar superfields in order to take the vector component field to build the chargeless complex vector superpartner where the respective field strength transforms into matter fields by a global U1 gauge symmetry. For the aim of dealing with consistent terms without breaking the global U1 symmetry we imposes a choice to the complex combination revealing a kind of symmetry between the choices and eliminates the extra degrees of freedom which is consistent with the supersymmetry. As the usual case the mass supersymmetric sector contributes as a complement to dynamics of the model. We obtain the equations of motion of the Proca’s type field for the chiral spinor fields and for the scalar field on the mass-shell which show the same mass as expected. This work establishes the first steps to extend the analysis of charged massive vector field in a supersymmetric scenario.
International Nuclear Information System (INIS)
Kucheryavy, V.I.
1993-01-01
The character of a canonical Ward identities violation in the quantum field theory (QFT) is extremely important for QFT itself and for its applications in physics. Triangle spinor amplitudes are the most popular objects of QFT in such investigations. The result of an application some effective realization of the Bogoliubov-Parasiuk (BP) renormalization scheme to the well-known subject is present
Realizing dignity as a part of intercultural competence
DEFF Research Database (Denmark)
Breunig, Steven
2014-01-01
The aim of this paper is to present the concept of dignity as a refl ective concept that may serve as a strategy for enhancing intercultural competence. Within the fi eld of intercultural communication, intercultural competence seeks to impart essential knowledge and skills for engaging...... within intercultural communication. This project contributes to the objectives of intercultural communication and competence by theorizing how awareness of social dynamics and emotional regulation may support the realization of dignity during intercultural encounters. Dignity may complement other...... in intercultural encounters with cognitive, behavioral and affective competence. Dignity contributes to intercultural competence by enabling persons to view the social world anew. In this paper, dignity is conceptualized as the development and self-expression of persons free from social categorization, while...
Landau-Ginzburg Realization of Open String TFT
Brunner, I; Lerche, Wolfgang; Scheuner, B; Brunner, Ilka; Herbst, Manfred; Lerche, Wolfgang; Scheuner, Bernhard
2006-01-01
We investigate B-type topological Landau-Ginzburg theory with one variable, with D2-brane boundary conditions. We find that the allowed brane configurations are determined in terms of the possible factorizations of the superpotential, and compute the corresponding open string chiral rings. These are characterized by bosonic and fermionic generators that satisfy certain relations. Moreover we show that the disk correlators, being continuous functions of deformation parameters, satisfy the topological sewing constraints, thereby proving consistency of the theory. In addition we show that the open string LG model is, in its content, equivalent to a certain triangulated category introduced by Kontsevich, and thus may be viewed as a concrete physical realization of it.
Pedagogical Dramas and Transformational Play: Realizing Narrative through Videogames Design
Barab, Sasha A.; Dodge, Tyler; Ingram-Goble, Adam; Volk, Charlene; Peppler, Kylie; Pettyjohn, Patrick; Solomou, Maria
Whereas traditionally stories involve an author, a performer, and an audience, much of the power of videogames as media for advancing narrative springs from their affordance for the player to occupy more than one role—and sometimes all three—simultaneously. In the narratively-rich videogames that we design, players have the opportunity to perform actions, experience consequences, and reflect on the underlying social values that these situations were designed to engage. Here, our focus is on the use of these games to engage children in experiencing ideological struggles associated with realizing social commitments. Toward this end, we will present our theoretical argument for the power of games as a contemporary story medium, grounding this discussion in the demonstration of three game design projects and their implementations.
Experimental Realization of High-Efficiency Counterfactual Computation.
Kong, Fei; Ju, Chenyong; Huang, Pu; Wang, Pengfei; Kong, Xi; Shi, Fazhan; Jiang, Liang; Du, Jiangfeng
2015-08-21
Counterfactual computation (CFC) exemplifies the fascinating quantum process by which the result of a computation may be learned without actually running the computer. In previous experimental studies, the counterfactual efficiency is limited to below 50%. Here we report an experimental realization of the generalized CFC protocol, in which the counterfactual efficiency can break the 50% limit and even approach unity in principle. The experiment is performed with the spins of a negatively charged nitrogen-vacancy color center in diamond. Taking advantage of the quantum Zeno effect, the computer can remain in the not-running subspace due to the frequent projection by the environment, while the computation result can be revealed by final detection. The counterfactual efficiency up to 85% has been demonstrated in our experiment, which opens the possibility of many exciting applications of CFC, such as high-efficiency quantum integration and imaging.
CONCEPTUAL APPROACHES TO FORMING MECHANISM OF INVESTMENT SAFETY REALIZATION
Directory of Open Access Journals (Sweden)
Vladimir Talover
2016-11-01
Full Text Available The purpose of the paper is theoretical justification of theoretical approaches while developing the mechanism of the state investment safety. The tasks of the system of the national economy investment safety are the following: developing investment potential, creating favourable investment climate, forming mechanisms of stable investment activity in the key branches of economy. At the same time, it should also be noted that the complex approach that would allow sufficiently justifying and practically solve the problems of defining indicators, factors of the investment policy and directions of its assurance in realization of the mechanism of investment policy is not sufficiently developed nowadays. This fact determines research topicality. The issue of assuring investment safety is of a special importance in Ukraine that has to assure market economy development, to overcome deformations in the economy structure, to renew products and production apparatus in the industry, to master new kinds of activities. Methodology. The survey is based on the generalization and development of views of the scientific-economic schools, uses approaches of the international agencies and recommendation and normative materials of Ukraine concerning realization of the state investment policy as a totality of interrelated levels and subsystems that allows establishing main functions of the investment safety system. Results of the survey shows that the mechanism of investment safety includes some kinds, forms and methods of organizing investment relations and investment activity, ways of their quantitative determination and establishing interdependence. The concept of investment policy is based on the complex approach and includes the blocks which are locally structured in such way that they allow forming adequate system of its indicators and conducting monitoring of their changes under the influence of the determined factors. The peculiarities and elements of
Realization of Multi-Delay Filter Using Fermat Number Transforms
Alaeddine, Hamzé Haidar; Baghious, El Houssaïn; Madre, Guillaume; Burel, Gilles
This paper is about an efficient implementation of adaptive filtering for echo cancelers. The first objective of this paper is to propose a simplified method of the flexible block Multi-Delay Filter (MDF) algorithm in the time-domain. Then, we will derive a new method for the step-size adaptation coefficient. The second objective is about the realization of a Block Proportionate Normalized Least Mean Squares (BPNLMS++) with the simplified MDF (SMDF) implementation. Using the new step-size method and the smaller block dimension proposed by SMDF, we achieve a faster convergence of the adaptive process with a limited computational cost. Then, an efficient implementation of the new procedure (SMDF-BPNLMS++) block filtering is proposed using Fermat Number Transform, which can significantly reduce the computation complexity of filter implantation on Digital Signal Processor.
Realization of a Service Robot for Cleaning Spherical Surfaces
Directory of Open Access Journals (Sweden)
Houxiang Zhang
2005-03-01
Full Text Available There are more and more buildings with complicated shape emerging all over the world. Their walls require constant cleaning which is difficult to realize. In this paper, based on analyzing the characteristics of the working target, a new kind of auto-climbing robot is proposed, which is used for cleaning the spherical surface of the National GrandTheatre in China. The robots' mechanism and unique aspects are presented in detail. A distributed controller based onCAN bus is designed to meet the requirements of controlling the robot. The control system is divided into 6 parts, fiveCAN bus control nodes and a remote controller, which are designed and established based mainly on the P80C592. Finally, the motion function is described in detail. The experimental results confirm the principle described above andthe robot's ability to work on the spherical surface.
Realization of a passive micromixer using herringbone structure
Whulanza, Yudan; Utomo, Muhammad S.; Hilman, Adam
2018-02-01
Micromixing is an important research area for a variety of applications in sensing and diagnostics. In this paper, we are trying to develop an overall understanding of the process of mixing by allowing two fluid flows to flow through various asymmetrical structures. We have successfully realized and compared the performance of different passive micromixer designs based on the idea of staggered herringbone micromixer. The herringbone structure is expected to affect the flow rate. We design few microchannels using varieties on velocity, height and distance between herringbone. The layout of the structure is based on the staggered herringbone bilayers where the layer is positioned on the bottom wall of the microchannel. From simulation and experiment, it is known that the height of the channel and herringbone structure affect the flow, and the most effective height of the main channel and herringbone structure is 0.3 and 0.14 mm (2:1 ratio).
The management and realizing of image data flow in PACS
International Nuclear Information System (INIS)
Tao Yonghao; Miao Jingtao
2002-01-01
Objective: To explore the management model and realizing of PACS image data-flow. Methods: Based on the implementing environment and management model of PACS image data-flow after full digital reengineering for radiology department in Shanghai First Hospital was completed, analysis on image data flow types, procedure, and achieving pattern were conducted. Results: Two kinds of image data-flow management were set up for the PACS of Shanghai First Hospital, which included image archiving procedure and image forward procedure. The former was implemented with central management model while the latter was achieved with a program that functionally acted as workflow management running on the central server. Conclusion: The image data-flow management pattern, as a key factor for PACS, has to be designed and implemented functionally and effectively depending on the performance environment, the tasks and requirements specified to particular user
Concentric circular focusing reflector realized using high index contrast gratings
Fang, Wenjing; Huang, Yongqing; Fei, Jiarui; Duan, Xiaofeng; Liu, Kai; Ren, Xiaomin
2017-11-01
A non-periodic concentric circular high index contrast grating (CC-HCG) focusing reflector on 500 nm silicon-on-insulator (SOI) platform is fabricated and experimentally demonstrated. The proposed mirror is realized with phase modulation of wave front in a high reflectivity region. The circular structure based HCG focusing reflector has a spot of high concentration at the 10.87 mm with normal incidence for radially polarization, along with the center wavelength set at 1550 nm. The FWHM spot size of the focusing beam decreases to 260 μm, and the intensity increases to 1.26 compared with the incident beam. The focusing efficiency of about 80% is observed at 1550 nm in the experimental measurement.
Realizing compact system for Schlieren visualization of transonic flows
International Nuclear Information System (INIS)
Bassi, F.; Osnaghi, C.; Savini, M.
1992-01-01
This paper describes a Schlieren system for flow visualization thought to overcome most of the drawbacks connected with the Z-configuration usually adopted: lack of transportability, wide overall dimensions, long and difficult alignment of the components, restricted sensitivity. The system, originally designed and realized, is of the double-pass type with all the emitting and receiving components mounted on an optical table and aligned during the initial assembly. The paper shows both monochromatic (Helium-Neon laser) and white-light (Mercury or Xenon arc lamps) visualizations of flames and transonic flows in calibrating nozzles and in turbine cascades in a wind tunnel. The accuracy and versatility displayed make this Schlieren system easily usable in fluid dynamics researches
Working Memory: Maintenance, Updating, and the Realization of Intentions
Nyberg, Lars; Eriksson, Johan
2016-01-01
“Working memory” refers to a vast set of mnemonic processes and associated brain networks, relates to basic intellectual abilities, and underlies many real-world functions. Working-memory maintenance involves frontoparietal regions and distributed representational areas, and can be based on persistent activity in reentrant loops, synchronous oscillations, or changes in synaptic strength. Manipulation of content of working memory depends on the dorsofrontal cortex, and updating is realized by a frontostriatal ‘“gating” function. Goals and intentions are represented as cognitive and motivational contexts in the rostrofrontal cortex. Different working-memory networks are linked via associative reinforcement-learning mechanisms into a self-organizing system. Normal capacity variation, as well as working-memory deficits, can largely be accounted for by the effectiveness and integrity of the basal ganglia and dopaminergic neurotransmission. PMID:26637287
Full service access networks: experimental realization and performance
Faulkner, David W.; Quayle, Alan; Smith, Phillip A.; Clarke, Don; Fisher, Simon; Adams, Richard; Kelly, James; Smee, Dave; Cook, John G.
1997-10-01
This paper describes how an experimental full services access network has been constructed at BT Labs and presents views on how its performance could be improved to meet the reliability and traffic loading requirements expected in real applications such as fiber to the business and fiber to the cabinet. The experimental network included: asynchronous transfer mode (ATM) switch, an ATM passive optical network (PON), very high speed digital subscriber loop (VDSL) customer drop and ATM forum 25 Mbit/s customer network. The design and realization of the VDSL customer drop, the signaling system and the interfaces between the system elements formed a major part of the design and construction work at BT Labs. The ability to cope with varying service demand and achieving the necessary quality of service are important requirements for roll-out systems. This paper describes how these requirements could be met in the design of future proprietary equipment.
Experimental Realization of High-Efficiency Counterfactual Computation
Kong, Fei; Ju, Chenyong; Huang, Pu; Wang, Pengfei; Kong, Xi; Shi, Fazhan; Jiang, Liang; Du, Jiangfeng
2015-08-01
Counterfactual computation (CFC) exemplifies the fascinating quantum process by which the result of a computation may be learned without actually running the computer. In previous experimental studies, the counterfactual efficiency is limited to below 50%. Here we report an experimental realization of the generalized CFC protocol, in which the counterfactual efficiency can break the 50% limit and even approach unity in principle. The experiment is performed with the spins of a negatively charged nitrogen-vacancy color center in diamond. Taking advantage of the quantum Zeno effect, the computer can remain in the not-running subspace due to the frequent projection by the environment, while the computation result can be revealed by final detection. The counterfactual efficiency up to 85% has been demonstrated in our experiment, which opens the possibility of many exciting applications of CFC, such as high-efficiency quantum integration and imaging.
Non-linear realizations and higher curvature supergravity
Energy Technology Data Exchange (ETDEWEB)
Farakos, F. [Dipartimento di Fisica e Astronomia ' ' Galileo Galilei' ' , Universita di Padova (Italy); INFN, Sezione di Padova (Italy); Ferrara, S. [Department of Theoretical Physics, Geneva (Switzerland); INFN - Laboratori Nazionali di Frascati, Frascati (Italy); Department of Physics and Astronomy, Mani L. Bhaumik Institute for Theoretical Physics, U.C.L.A., Los Angeles, CA (United States); Kehagias, A. [Physics Division, National Technical University of Athens (Greece); Luest, D. [Arnold Sommerfeld Center for Theoretical Physics, Muenchen (Germany); Max-Planck-Institut fuer Physik, Muenchen (Germany)
2017-12-15
We focus on non-linear realizations of local supersymmetry as obtained by using constrained superfields in supergravity. New constraints, beyond those of rigid supersymmetry, are obtained whenever curvature multiplets are affected as well as higher derivative interactions are introduced. In particular, a new constraint, which removes a very massive gravitino is introduced, and in the rigid limit it merely reduces to an explicit supersymmetry breaking. Higher curvature supergravities free of ghosts and instabilities are also obtained in this way. Finally, we consider direct coupling of the goldstino multiplet to the super Gauss-Bonnet multiplet and discuss the emergence of a new scalar degree of freedom. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Design and realization of high voltage disconnector condition monitoring system
Shi, Jinrui; Xu, Tianyang; Yang, Shuixian; Li, Buoyang
2017-08-01
The operation status of the high voltage disconnector directly affects the safe and stable operation of the power system. This article uses the wireless frequency hopping communication technology of the communication module to achieve the temperature acquisition of the switch contacts and high voltage bus, to introduce the current value of the loop in ECS, and judge the operation status of the disconnector by considering the ambient temperature, calculating the temperature rise; And through the acquisition of the current of drive motor in the process of switch closing and opening, and fault diagnosis of the disconnector by analyzing the change rule of the drive motor current, the condition monitoring of the high voltage disconnector is realized.
Realization of matching conditions for high-resolution spectrometers
International Nuclear Information System (INIS)
Fujita, H.; Fujita, Y.; Berg, G.P.A.; Bacher, A.D.; Foster, C.C.; Hara, K.; Hatanaka, K.; Kawabata, T.; Noro, T.; Sakaguchi, H.; Shimbara, Y.; Shinada, T.; Stephenson, E.J.; Ueno, H.; Yosoi, M.
2002-01-01
For precise measurements of nuclear-reaction spectra using a beam from an accelerator, a high-resolution magnetic spectrometer is a powerful tool. The full capability of a magnetic spectrometer, however, can be achieved only if the characteristics of the beam coming from the accelerator are matched to those required by the spectrometer by properly adjusting the beam line conditions. The matching methods, lateral dispersion matching, focus matching and also the kinematic correction compensate the spectrum line-broadening effects caused by the beam momentum spread and reaction kinematics. In addition, angular dispersion matching should be performed if good resolution of the scattering angle is important. Diagnostic methods developed to realize these matching conditions for the spectrometers K600 at IUCF and Grand Raiden at RCNP are presented
Clean Floquet Time Crystals: Models and Realizations in Cold Atoms
Huang, Biao; Wu, Ying-Hai; Liu, W. Vincent
2018-03-01
Time crystals, a phase showing spontaneous breaking of time-translation symmetry, has been an intriguing subject for systems far away from equilibrium. Recent experiments found such a phase in both the presence and the absence of localization, while in theories localization by disorder is usually assumed a priori. In this work, we point out that time crystals can generally exist in systems without disorder. A series of clean quasi-one-dimensional models under Floquet driving are proposed to demonstrate this unexpected result in principle. Robust time crystalline orders are found in the strongly interacting regime along with the emergent integrals of motion in the dynamical system, which can be characterized by level statistics and the out-of-time-ordered correlators. We propose two cold atom experimental schemes to realize the clean Floquet time crystals, one by making use of dipolar gases and another by synthetic dimensions.
Realization of matching conditions for high-resolution spectrometers
Fujita, H; Berg, G P A; Bacher, A D; Foster, C C; Hara, K; Hatanaka, K; Kawabata, T; Noro, T; Sakaguchi, H; Shimbara, Y; Shinada, T; Stephenson, E J; Ueno, H; Yosoi, M
2002-01-01
For precise measurements of nuclear-reaction spectra using a beam from an accelerator, a high-resolution magnetic spectrometer is a powerful tool. The full capability of a magnetic spectrometer, however, can be achieved only if the characteristics of the beam coming from the accelerator are matched to those required by the spectrometer by properly adjusting the beam line conditions. The matching methods, lateral dispersion matching, focus matching and also the kinematic correction compensate the spectrum line-broadening effects caused by the beam momentum spread and reaction kinematics. In addition, angular dispersion matching should be performed if good resolution of the scattering angle is important. Diagnostic methods developed to realize these matching conditions for the spectrometers K600 at IUCF and Grand Raiden at RCNP are presented.
Realizing the next generation of CPV cells using transfer printing
Lumb, Matthew P.; Schmieder, Kenneth J.; González, María; Mack, Shawn; Yakes, Michael K.; Meitl, Matthew; Burroughs, Scott; Ebert, Chris; Bennett, Mitchell F.; Forbes, David V.; Sheng, Xing; Rogers, John A.; Walters, Robert J.
2015-09-01
Transfer-printing is an important, commercial technology for manufacturing state of the art CPV modules, and has emerged recently as a key enabling technology for the realization of ultra-high-efficiency, mechanically stacked III-V solar cells with low cost. This paper presents the latest results for microscale CPV cells grown on GaAs, InP and GaSb substrates for ultra-high-efficiency, four-terminal, mechanically stacked architectures. The latest findings from a combination of modeling, growth, processing and characterization of single and multijunction solar cells are described, and the roadmap to the long-term goal of using transfer-printing to produce the first solar cell with 50% conversion efficiency is outlined.
Industrial Application of Configurators: From Motivations to Realized Benefits
DEFF Research Database (Denmark)
Kristjansdottir, Katrin; Shafiee, Sara; Hvam, Lars
to support companies applying mass customization strategies. This articles analysis the relationship between the initial motivations manufacturing companies have for implementing configurators and the realized benefits from the application of configurators. The results presented in this paper are based......Manufacturing companies are increasingly seeking to gain the benefits from mass customization strategies as a response to increased customers’ demand for customized products. To automate the process of generating products’ specifications and guide the sales process, configurators are commonly used...... on a survey followed with interviews in 22 industrial companies. The findings show that the main motivations can be grouped into seven categories, where the successfulness of achieving the targeted benefits varies between the individual categories. Furthermore, the results highlights that substantial benefits...
Design and realization of an autonomous solar system
Gaga, A.; Diouri, O.; Es-sbai, N.; Errahimi, F.
2017-03-01
The aim of this work is the design and realization of an autonomous solar system, with MPPT control, a regulator charge/discharge of batteries, an H-bridge multi-level inverter with acquisition system and supervising based on a microcontroller. The proposed approach is based on developing a software platform in the LabVIEW environment which gives the system a flexible structure for controlling, monitoring and supervising the whole system in real time while providing power maximization and best quality of energy conversion from DC to AC power. The reliability of the proposed solar system is validated by the simulation results on PowerSim and experimental results achieved with a solar panel, a Lead acid battery, solar regulator and an H-bridge cascaded topology of single-phase inverter.
Realization of a Service Robot for Cleaning Spherical Surfaces
Directory of Open Access Journals (Sweden)
Guanghua Zong
2008-11-01
Full Text Available There are more and more buildings with complicated shape emerging all over the world. Their walls require constant cleaning which is difficult to realize. In this paper, based on analyzing the characteristics of the working target,a new kind of auto-climbing robot is proposed, which is used for cleaning the spherical surface of the National GrandTheatre in China. The robots' mechanism and unique aspects are presented in detail. A distributed controller based onCAN bus is designed to meet the requirements of controlling the robot. The control system is divided into 6 parts, fiveCAN bus control nodes and a remote controller, which are designed and established based mainly on the P80C592.Finally, the motion function is described in detail. The experimental results confirm the principle described above andthe robot's ability to work on the spherical surface.
Experimental realization of a minimal microscopic heat engine
Argun, Aykut; Soni, Jalpa; Dabelow, Lennart; Bo, Stefano; Pesce, Giuseppe; Eichhorn, Ralf; Volpe, Giovanni
2017-11-01
Microscopic heat engines are microscale systems that convert energy flows between heat reservoirs into work or systematic motion. We have experimentally realized a minimal microscopic heat engine. It consists of a colloidal Brownian particle optically trapped in an elliptical potential well and simultaneously coupled to two heat baths at different temperatures acting along perpendicular directions. For a generic arrangement of the principal directions of the baths and the potential, the symmetry of the system is broken, such that the heat flow drives a systematic gyrating motion of the particle around the potential minimum. Using the experimentally measured trajectories, we quantify the gyrating motion of the particle, the resulting torque that it exerts on the potential, and the associated heat flow between the heat baths. We find excellent agreement between the experimental results and the theoretical predictions.
Experiencing and the realization of motherhood by teenage mothers
Directory of Open Access Journals (Sweden)
Ewa Rzechowska
2015-04-01
Full Text Available Background Early motherhood constitutes a difficult challenge for girls, and the level of their performance in that role is varied. In this article, teenage motherhood as a process is considered. The objective of the research was to determine the paths by which teenage girls enter the mother role. Particular attention was paid to the nature of individual differences in the ways of experiencing and the realization of the successive steps of teenage motherhood: how the girls reacted to the fact of being a mother, what they experienced and how they behaved during pregnancy and performed child care. Participants and procedure In the research, 166 mothers who had given birth to their children between the 15th and 19th year of life were included (at the moment of giving birth to the child, the age of the mother was M = 17.22. A follower interview was used. It was directed towards recreating the course of their lives from the period preceding becoming pregnant to the period of pregnancy and looking after the child, taking into consideration the complex situations connected with life and development of the female teenagers. Results In the research, we applied the Reconstruction Strategy of the Process Transformation, setting the direction of qualitative analyses: (1 the level of single cases (case study, and (2 the level of the collection of cases (extracting groups of girls with common characteristics using the artificial intelligence algorithm C4.5. The analysis revealed the diversity and the internal structure of paths of the experience and realization of early motherhood: from negating oneself as a responsible mother to accepting the role of mother. Conclusions The final result is constituted by the model revealing the transformation of teenage motherhood and mechanisms underlying it.
Consistent realization of Celestial and Terrestrial Reference Frames
Kwak, Younghee; Bloßfeld, Mathis; Schmid, Ralf; Angermann, Detlef; Gerstl, Michael; Seitz, Manuela
2018-03-01
The Celestial Reference System (CRS) is currently realized only by Very Long Baseline Interferometry (VLBI) because it is the space geodetic technique that enables observations in that frame. In contrast, the Terrestrial Reference System (TRS) is realized by means of the combination of four space geodetic techniques: Global Navigation Satellite System (GNSS), VLBI, Satellite Laser Ranging (SLR), and Doppler Orbitography and Radiopositioning Integrated by Satellite. The Earth orientation parameters (EOP) are the link between the two types of systems, CRS and TRS. The EOP series of the International Earth Rotation and Reference Systems Service were combined of specifically selected series from various analysis centers. Other EOP series were generated by a simultaneous estimation together with the TRF while the CRF was fixed. Those computation approaches entail inherent inconsistencies between TRF, EOP, and CRF, also because the input data sets are different. A combined normal equation (NEQ) system, which consists of all the parameters, i.e., TRF, EOP, and CRF, would overcome such an inconsistency. In this paper, we simultaneously estimate TRF, EOP, and CRF from an inter-technique combined NEQ using the latest GNSS, VLBI, and SLR data (2005-2015). The results show that the selection of local ties is most critical to the TRF. The combination of pole coordinates is beneficial for the CRF, whereas the combination of Δ UT1 results in clear rotations of the estimated CRF. However, the standard deviations of the EOP and the CRF improve by the inter-technique combination which indicates the benefits of a common estimation of all parameters. It became evident that the common determination of TRF, EOP, and CRF systematically influences future ICRF computations at the level of several μas. Moreover, the CRF is influenced by up to 50 μas if the station coordinates and EOP are dominated by the satellite techniques.
Spoof surface plasmon based planar antennas for the realization of Terahertz hotspots
Zhang, Yusheng; Han, Zhanghua
2015-01-01
Novel spoof surface plasmon based terahertz (THz) antennas are realized using a few number of rectangular grooves perforated in ultrathin metal stripes and the properties of them, including both scattering cross sections and field enhancement, are numerically analyzed. The dependence of these properties on the incident angle and groove number is discussed and the results show that sharp resonances in scattering cross section spectra associated with strong local field enhancement can be achieved. These resonances are due to the formation of Fabry-Perot resonances of the spoof surface plasmon mode and it is found that the order of resonance exhibiting strongest field enhancements is found to coincide with the number of grooves at normal incidence, due to hybridization of the antenna resonance with the individual groove resonance. The terahertz hotspots within the grooves at resonances due to the local field enhancement may open up new possibilities for the investigation of terahertz-matter interactions and boost a variety of THz applications including novel sensing and THz detections. The planar stripe antennas with sharper resonances than dipolar-like resonances, together with their ease of fabrication may also promise new design methodology for metamaterials. PMID:26691003
Aharonov-Bohm effect for a fermion field in a planar black hole ''spacetime''
Energy Technology Data Exchange (ETDEWEB)
Anacleto, M.A.; Mohammadi, A. [Universidade Federal de Campina Grande, Departamento de Fisica, Caixa Postal 10071, Campina Grande, Paraiba (Brazil); Brito, F.A. [Universidade Federal de Campina Grande, Departamento de Fisica, Caixa Postal 10071, Campina Grande, Paraiba (Brazil); Universidade Federal da Paraiba, Departamento de Fisica, Caixa Postal 5008, Joao Pessoa, Paraiba (Brazil); Passos, E. [Universidade Federal de Campina Grande, Departamento de Fisica, Caixa Postal 10071, Campina Grande, Paraiba (Brazil); Universidade Federal do Rio de Janeiro, Instituto de Fisica, Caixa Postal 21945, Rio de Janeiro (Brazil)
2017-04-15
In this paper we consider the dynamics of a massive spinor field in the background of the acoustic black hole spacetime. Although this effective metric is acoustic and describes the propagation of sound waves, it can be considered as a toy model for the gravitational black hole. In this manner, we study the properties of the dynamics of the fermion field in this ''gravitational'' rotating black hole as well as the vortex background. We compute the differential cross section through the use of the partial wave approach and show that an effect similar to the gravitational Aharonov-Bohm effect occurs for the massive fermion field moving in this effective metric. We discuss the limiting cases and compare the results with the massless scalar field case. (orig.)
Realization of 16-channel digital PGC demodulator for fiber laser sensor array
Energy Technology Data Exchange (ETDEWEB)
Wang Lin; He Jun; Li Fang; Liu Yuliang, E-mail: wlcas@semi.ac.cn [Optoelectronics System Laboratory, Institute of Semiconductors, Chinese Academy of Sciences, PO Box 912, Beijing 100083 (China)
2011-02-01
This paper describes a 16-element DFB FL (distributed feedback fiber laser) sensor array system interrogated by NI-PXI-based (PCI extensions for Instrumentation) digital PGC (phase generated carrier) technique. The lasing wavelengths of the DFB FLs are changed by the external strains or temperatures, and hence they can be used as sensors by detecting the wavelength shifts. An unbalanced MI (Michelson interferometer) is employed in the sensor array system to amplify the wavelength shifts of DFB FL sensors to detectable phase shifts. The output phase signals of the MI are separated into different channels by a DWDM, and then detected by a low-noise photodiode array. The digital PGC algorithm is realized on a PXI platform (NI, National Instruments), which consists of three FPGA (Field Programmable Gate Array) modules and a high performance system controller. The normalization of the interference fringe is proposed and realized in this paper to reduce the influence of the light intensity fluctuations, and a trigger mechanism is introduced into the digital multi-channel PGC demodulation scheme to synchronize the date among different channels. A 16-element DFB fiber laser sensor array system has been set up in the experiment and the demodulated results have demonstrated a minimum detectable wavelength shift of 1x10{sup -6} pmA/{radical}Hz, a linearity of as high as 0.9994, and a dynamic range of 110dB-100Hz.
Realization of a Hole-Doped Mott Insulator on a Triangular Silicon Lattice
Ming, Fangfei; Johnston, Steve; Mulugeta, Daniel; Smith, Tyler S.; Vilmercati, Paolo; Lee, Geunseop; Maier, Thomas A.; Snijders, Paul C.; Weitering, Hanno H.
2017-12-01
The physics of doped Mott insulators is at the heart of some of the most exotic physical phenomena in materials research including insulator-metal transitions, colossal magnetoresistance, and high-temperature superconductivity in layered perovskite compounds. Advances in this field would greatly benefit from the availability of new material systems with a similar richness of physical phenomena but with fewer chemical and structural complications in comparison to oxides. Using scanning tunneling microscopy and spectroscopy, we show that such a system can be realized on a silicon platform. The adsorption of one-third monolayer of Sn atoms on a Si(111) surface produces a triangular surface lattice with half filled dangling bond orbitals. Modulation hole doping of these dangling bonds unveils clear hallmarks of Mott physics, such as spectral weight transfer and the formation of quasiparticle states at the Fermi level, well-defined Fermi contour segments, and a sharp singularity in the density of states. These observations are remarkably similar to those made in complex oxide materials, including high-temperature superconductors, but highly extraordinary within the realm of conventional s p -bonded semiconductor materials. It suggests that exotic quantum matter phases can be realized and engineered on silicon-based materials platforms.
Energy Technology Data Exchange (ETDEWEB)
Stevanovic, Vladan [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Jones, Eric [National Renewable Energy Laboratory (NREL), Golden, CO (United States)
2017-11-03
With few systems of technological interest having been studied as extensively as elemental silicon, there currently exists a wide disparity between the number of predicted low-energy silicon polymorphs and those that have been experimentally realized as metastable at ambient conditions. We put forward an explanation for this disparity wherein the likelihood of formation of a given polymorph under near-equilibrium conditions can be estimated on the basis of mean-field isothermal-isobaric (N,p,T) ensemble statistics. The probability that a polymorph will be experimentally realized is shown to depend upon both the hypervolume of that structure's potential energy basin of attraction and a Boltzmann factor weight containing the polymorph's potential enthalpy per particle. Both attributes are calculated using density functional theory relaxations of randomly generated initial structures. We find that the metastable polymorphism displayed by silicon can be accounted for using this framework to the exclusion of a very large number of other low-energy structures.
Mansoor, Muhammad Mudassir; Abbas, Naeem; Shad, Sarfraz Ali; Pathan, Attaullah Khan; Razaq, Muhammad
2013-10-01
The common green lacewing Chrysoperla carnea is a key biological control agent employed in integrated pest management (IPM) programs for managing various insect pests. A field collected population of C. carnea was selected for emamectin benzoate resistance in the laboratory and fitness costs and realized heritability were investigated. After five generations of selection with emamectin benzoate, C. carnea developed a 318-fold resistance to the insecticide. The resistant population had a relative fitness of 1.49, with substantially higher emergence rate of healthy adults, fecundity and hatchability and shorter larval duration, pupal duration, and development time compared to the susceptible population. Mean population growth rates; such as the intrinsic rate of natural population increase and biotic potential were higher for the emamectin benzoate selected population compared to the susceptible population. The realized heritability (h(2)) value of emamectin benzoate resistance was 0.34 in emamectin benzoate selected population of C. carnea. Chrysoperla species which show resistance to insecticides makes them compatible with those IPM systems where emamectin benzoate is employed.
Limongi, Tania
2015-06-01
Material science, cell biology, and engineering are all part of the research field of tissue engineering. It is the application of knowledge, methods and instrumentations of engineering and life science to the development of biocompatible solutions for repair and/or replace tissues and damaged organs. Last generation microfabrication technologies utilizing natural and synthetic biomaterials allow the realization of scaffolds resembling tissue-like structures as skin, brain, bones, muscles, cartilage and blood vessels. In this work we describe an effective and simple micromolding fabrication process allowing the realization of 3D polycaprolactone (PCL) scaffold for human neural stem cells (hNSC) culture. Scanning Electron Microscopy has been used to investigate the micro and nano features characterizing the surface of the device. Immunofluorescence analysis showed how, after seeding cells onto the substrate, healthy astrocytes grew up in a well-organized 3D network. Thus, we proposed this effective fabrication method for the production of nanopatterned PCL pillared scaffold providing a biomimetic environment for the growth of hNSC, a promising and efficient means for future applications in tissue engineering and regenerative medicine.
Does Realized Skewness Predict the Cross-Section of Equity Returns?
DEFF Research Database (Denmark)
Amaya, Diego; Christoffersen, Peter; Jacobs, Kris
We use intraday data to compute weekly realized variance, skewness, and kurtosis for equity returns and study the realized moments’ time-series and cross-sectional properties. We investigate if this week’'s realized moments are informative for the cross-section of next week'’s stock returns. We...... find a very strong negative relationship between realized skewness and next week’'s stock returns. A trading strategy that buys stocks in the lowest realized skewness decile and sells stocks in the highest realized skewness decile generates an average weekly return of 24 basis points with a t...
Quantum learning of classical stochastic processes: The completely positive realization problem
International Nuclear Information System (INIS)
Monràs, Alex; Winter, Andreas
2016-01-01
Among several tasks in Machine Learning, a specially important one is the problem of inferring the latent variables of a system and their causal relations with the observed behavior. A paradigmatic instance of this is the task of inferring the hidden Markov model underlying a given stochastic process. This is known as the positive realization problem (PRP), [L. Benvenuti and L. Farina, IEEE Trans. Autom. Control 49(5), 651–664 (2004)] and constitutes a central problem in machine learning. The PRP and its solutions have far-reaching consequences in many areas of systems and control theory, and is nowadays an important piece in the broad field of positive systems theory. We consider the scenario where the latent variables are quantum (i.e., quantum states of a finite-dimensional system) and the system dynamics is constrained only by physical transformations on the quantum system. The observable dynamics is then described by a quantum instrument, and the task is to determine which quantum instrument — if any — yields the process at hand by iterative application. We take as a starting point the theory of quasi-realizations, whence a description of the dynamics of the process is given in terms of linear maps on state vectors and probabilities are given by linear functionals on the state vectors. This description, despite its remarkable resemblance with the hidden Markov model, or the iterated quantum instrument, is however devoid of any stochastic or quantum mechanical interpretation, as said maps fail to satisfy any positivity conditions. The completely positive realization problem then consists in determining whether an equivalent quantum mechanical description of the same process exists. We generalize some key results of stochastic realization theory, and show that the problem has deep connections with operator systems theory, giving possible insight to the lifting problem in quotient operator systems. Our results have potential applications in quantum machine
Atom lasers, coherent states, and coherence. I. Physically realizable ensembles of pure states
International Nuclear Information System (INIS)
A laser, be it an optical laser or an atom laser, is an open quantum system that produces a coherent beam of bosons (photons or atoms, respectively). Far above threshold, the stationary state ρ ss of the laser mode is a mixture of coherent-field states with random phase, or, equivalently, a Poissonian mixture of number states. This paper answers the question: can descriptions such as these, of ρ ss as a stationary ensemble of pure states, be physically realized? Here physical realization is as defined previously by us [H. M. Wiseman and J. A. Vaccaro, Phys. Lett. A 250, 241 (1998)]: an ensemble of pure states for a particular system can be physically realized if, without changing the dynamics of the system, an experimenter can (in principle) know at any time that the system is in one of the pure-state members of the ensemble. Such knowledge can be obtained by monitoring the baths to which the system is coupled, provided that coupling is describable by a Markovian master equation. Using a family of master equations for the (atom) laser, we solve for the physically realizable (PR) ensembles. We find that for any finite self-energy χ of the bosons in the laser mode, the coherent-state ensemble is not PR; the closest one can come to it is an ensemble of squeezed states. This is particularly relevant for atom lasers, where the self-energy arising from elastic collisions is expected to be large. By contrast, the number-state ensemble is always PR. As the self-energy χ increases, the states in the PR ensemble closest to the coherent-state ensemble become increasingly squeezed. Nevertheless, there are values of χ for which states with well-defined coherent amplitudes are PR, even though the atom laser is not coherent (in the sense of having a Bose-degenerate output). We discuss the physical significance of this anomaly in terms of conditional coherence (and hence conditional Bose degeneracy)
Quantum learning of classical stochastic processes: The completely positive realization problem
Energy Technology Data Exchange (ETDEWEB)
Monràs, Alex [Física Teòrica: Informació i Fenòmens Quàntics, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona) (Spain); Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543 (Singapore); Winter, Andreas [Física Teòrica: Informació i Fenòmens Quàntics, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona) (Spain); Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543 (Singapore); ICREA—Institució Catalana de Recerca i Estudis Avançats, Pg. Lluis Companys, 23, 08010 Barcelona (Spain)
2016-01-15
Among several tasks in Machine Learning, a specially important one is the problem of inferring the latent variables of a system and their causal relations with the observed behavior. A paradigmatic instance of this is the task of inferring the hidden Markov model underlying a given stochastic process. This is known as the positive realization problem (PRP), [L. Benvenuti and L. Farina, IEEE Trans. Autom. Control 49(5), 651–664 (2004)] and constitutes a central problem in machine learning. The PRP and its solutions have far-reaching consequences in many areas of systems and control theory, and is nowadays an important piece in the broad field of positive systems theory. We consider the scenario where the latent variables are quantum (i.e., quantum states of a finite-dimensional system) and the system dynamics is constrained only by physical transformations on the quantum system. The observable dynamics is then described by a quantum instrument, and the task is to determine which quantum instrument — if any — yields the process at hand by iterative application. We take as a starting point the theory of quasi-realizations, whence a description of the dynamics of the process is given in terms of linear maps on state vectors and probabilities are given by linear functionals on the state vectors. This description, despite its remarkable resemblance with the hidden Markov model, or the iterated quantum instrument, is however devoid of any stochastic or quantum mechanical interpretation, as said maps fail to satisfy any positivity conditions. The completely positive realization problem then consists in determining whether an equivalent quantum mechanical description of the same process exists. We generalize some key results of stochastic realization theory, and show that the problem has deep connections with operator systems theory, giving possible insight to the lifting problem in quotient operator systems. Our results have potential applications in quantum machine
International Nuclear Information System (INIS)
Capitaine, Nicole
2012-01-01
improvements in the fields of astrometry, celestial mechanics, geodynamics, geodesy, etc. Of special interest are the improvements in the model for variations in Earth's rotation, which, in turn, can provide better knowledge of the dynamics of the Earth's interior. These have also contributed to a significant improvement in the accuracy of the ephemerides of the solar system bodies as determined from modern measurements, with a large number of scientific applications. This paper recalls the main aspects of the recent IAU resolutions on reference systems as well as their consequences on the concepts, definitions, nomenclature and models that are suitable for the definition, realization and transformation of reference frames at a microarcsecond level.
Quantum learning of classical stochastic processes: The completely positive realization problem
Monràs, Alex; Winter, Andreas
2016-01-01
Among several tasks in Machine Learning, a specially important one is the problem of inferring the latent variables of a system and their causal relations with the observed behavior. A paradigmatic instance of this is the task of inferring the hidden Markov model underlying a given stochastic process. This is known as the positive realization problem (PRP), [L. Benvenuti and L. Farina, IEEE Trans. Autom. Control 49(5), 651-664 (2004)] and constitutes a central problem in machine learning. The PRP and its solutions have far-reaching consequences in many areas of systems and control theory, and is nowadays an important piece in the broad field of positive systems theory. We consider the scenario where the latent variables are quantum (i.e., quantum states of a finite-dimensional system) and the system dynamics is constrained only by physical transformations on the quantum system. The observable dynamics is then described by a quantum instrument, and the task is to determine which quantum instrument — if any — yields the process at hand by iterative application. We take as a starting point the theory of quasi-realizations, whence a description of the dynamics of the process is given in terms of linear maps on state vectors and probabilities are given by linear functionals on the state vectors. This description, despite its remarkable resemblance with the hidden Markov model, or the iterated quantum instrument, is however devoid of any stochastic or quantum mechanical interpretation, as said maps fail to satisfy any positivity conditions. The completely positive realization problem then consists in determining whether an equivalent quantum mechanical description of the same process exists. We generalize some key results of stochastic realization theory, and show that the problem has deep connections with operator systems theory, giving possible insight to the lifting problem in quotient operator systems. Our results have potential applications in quantum machine
Energy Technology Data Exchange (ETDEWEB)
Latimer, M. L.; Berdiyorov, G. R.; Xiao, Z. L.; Peeters, F. M.; Kwok, W. K.
2013-08-05
We report an anomalous matching effect in MoGe thin films containing pairs of circular holes arranged in such a way that four of those pairs meet at each vertex point of a square lattice. A remarkably pronounced fractional matching was observed in the magnetic field dependences of both the resistance and the critical current. At the half matching field the critical current can be even higher than that at zero field. This has never been observed before for vortices in superconductors with pinning arrays. Numerical simulations within the nonlinear Ginzburg-Landau theory reveal a square vortex ice configuration in the ground state at the half matching field and demonstrate similar characteristic features in the field dependence of the critical current, confirming the experimental realization of an artificial ice system for vortices for the first time.
Portfolio management using realized covariances: Evidence from Brazil
Directory of Open Access Journals (Sweden)
João F. Caldeira
2017-09-01
Full Text Available It is often argued that intraday returns can be used to construct covariance estimates that are more accurate than those based on daily returns. However, it is still unclear whether high frequency data provide more precise covariance estimates in markets more contaminated from microstructure noise such as higher bid-ask spreads and lower liquidity. We address this question by investigating the benefits of using high frequency data in the Brazilian equities market to construct optimal minimum variance portfolios. We implement alternative realized covariance estimators based on intraday returns sampled at alternative frequencies and obtain their dynamic versions using a multivariate GARCH framework. Our evidence based on a high-dimensional data set suggests that realized covariance estimators performed significantly better from an economic point of view in comparison to standard estimators based on low-frequency (close-to-close data as they delivered less risky portfolios. Resumo: Argumenta-se frequentemente que retornos intradiários podem ser usados para construir estimativas de covariâncias mais precisas em relação àquelas obtidas com retornos diários. No entanto, ainda não está claro se os dados de alta freqüência fornecem estimativas de covariância mais precisas em mercados mais contaminados pelo ruído da microestrutura, como maiores spreads entre ofertas de compra e venda e baixa liquidez. Abordamos essa questão investigando os benefícios do uso de dados de alta freqüência no mercado de ações brasileiro através da construção de portfólios ótimos de variância mínima. Implementamos diversos estimadores de covariâncias realizadas com base em retornos intradiários amostrados em diferentes frequências e obtemos suas versões dinâmicas usando uma estrutura GARCH multivariada. Nossa evidência baseada em um conjunto de dados de alta dimensão sugere que os estimadores de covariâncias realizadas obtiveram um desempenho
Status of the realization of the neutral beam test facility
International Nuclear Information System (INIS)
Toigo, Vanni
2015-01-01
The ITER Neutral Beam Injectors (NBI) are required to deliver 16.5 MW of additional heating power to the plasma, accelerating negative ions up to -1 MV with a beam current of 40A lasting up to 1 hour. Since these outstanding requirements were never achieved all together so far, the realization of a Neutral Beam Test Facility (NBTF), called PRIMA, currently under construction in Padova, was launched with the aim to test the operation of the NB injector and to study the relevant physical and technological issues, in advance to the implementation in ITER. Two projects are under development: MITICA and SPIDER. MITICA is a full scale prototype of the ITER NB injector; the design is based on a similar scheme and layout, with the same power supply system and also the control and protection systems are being designed according to the ITER rules and constraints. The HV components are procured by JADA; the low voltage ones and the injector are procured by F4E. SPIDER project is an ion source with the same characteristics of the ITER one, specifically addressed to study the issues related to the RF operation; for this reason, the beam energy is limited to 100keV. It can generate both Hydrogen and Deuterium Ions; the design includes provisions to filter electrons and also to allow the use of cesium to attain the high values of current density required. SPIDER is procured by F4E and INDA. The construction of PRIMA buildings and auxiliaries, started in autumn 2008, was completed in summer 2015. SPIDER plant systems procurement is well advanced and some systems are under installation or site acceptance tests. In 2016 integrated commissioning and power supply integrated tests will be performed followed by the beginning of the first experimental phase. MITICA design was completed; many procurement contracts have been signed or will be launched in the next months. Installation activity will start in December 2015 with the installation of the first HV power supply components provided
Realization of the electrical Sentinel 4 detector integration
Hermsen, M.; Hohn, R.; Skegg, M.; Woffinden, C.; Reulke, R.
2017-09-01
The detectors of the Sentinel 4 multi spectral imager are operated in flight at 215K while the analog electronics is operated at ambient temperature. The detector is cooled by means of a radiator. For thermal reasons no active component has been allowed in the cooled area closest to the detector as the passive radiator is restricted in its size. For thermal decoupling of detector and electronics a long distance between detector and electronics is considered ideal as thermal conductivity decreases with the length of the connection. In contradiction a short connection between detector and electronics is ideal for the electronic signals. Only a short connection ensures the signal integrity of both the weak detector output signal but similarly also the clock signals for driving the detector. From a mechanical and thermal point of view the connection requires a certain minimum length. The selected solution serves all these needs but had to approach the limits of what is electrically, mechanically and thermally feasible. In addition, shielding from internal (self distortion) and external distorting signals has to be realized for the connection between FEE(Front End Electronics) and detectors. At the time of the design of the flex it was not defined whether the mechanical structure between FEE and FPA (Focal Plane Assembly) would act as a shielding structure. The physical separation between CCD detector and the Front-end Electronics, the adverse EMI environment in which the instrument will be operated in (the location of the instrument on the satellite is in vicinity to a down-link K-band communication antenna of the S/C) require at least the video output signals to be shielded. Both detectors (a NIR and a UVVIS detector) are sensitive to contamination and difficult to be cleaned in case of any contamination. This brings up extreme cleanliness requirements for the detector in manufacturing and assembly. Effectively the detector has to be kept in an ISO 5 environment and
Energy Technology Data Exchange (ETDEWEB)
Pereira, S.H.; Guimarães, T.M., E-mail: shpereira@feg.unesp.br, E-mail: thiago.mogui@gmail.com [Universidade Estadual Paulista (Unesp), Faculdade de Engenharia, Guaratinguetá, Departamento de Física e Química, Av. Dr. Ariberto Pereira da Cunha 333, 12516-410, Guaratinguetá, SP (Brazil)
2017-09-01
In this paper we construct the complete evolution of the universe driven by the mass dimension one dark spinor called Elko, starting with inflation, passing by the matter dominated era and finishing with the recent accelerated expansion. The dynamic of the fermionic Elko field with a symmetry breaking type potential can reproduce all phases of the universe in a natural and elegant way. The dynamical equations in general case and slow roll conditions in the limit H || m {sub pl} are also presented for the Elko system. Numerical analysis for the number of e-foldings during inflation, energy density after inflation and for present time and also the actual size of the universe are in good agreement with the standard model of cosmology. An interpretation of the inflationary phase as a result of Pauli exclusion principle is also possible if the Elko field is treated as an average value of its quantum analogue.
Are fundamental niches larger than the realized? Testing a 50-year-old prediction by Hutchinson.
Soberón, J; Arroyo-Peña, B
2017-01-01
For more than 50 years ecological niches have been defined as combinations of multidimensional environmental conditions permitting a species to survive and reproduce. A fundamental niche (NF) is defined as the set of conditions within which a species can live in the absence of competitors, and a realized niche (NR) is a NF hypothetically reduced by competitive interactions (and some other limiting factors). This definition implies that NF is "larger" than NR, something that has been nearly universally accepted by ecologists. However, there have been few attempts at empirical tests. Here, we present a novel quantitative test using one-dimensional estimates of NF for 105 species of reptiles and amphibians, and estimates of NR obtained from ~1.4 x 104 field observations. To specify our test, we operationalize the original classification of niche types. Our results predominantly support the hypothesis that NF 'is larger' than NR and we highlight the theoretical and practical importance of quantifying niches.
Are fundamental niches larger than the realized? Testing a 50-year-old prediction by Hutchinson.
Directory of Open Access Journals (Sweden)
J Soberón
Full Text Available For more than 50 years ecological niches have been defined as combinations of multidimensional environmental conditions permitting a species to survive and reproduce. A fundamental niche (NF is defined as the set of conditions within which a species can live in the absence of competitors, and a realized niche (NR is a NF hypothetically reduced by competitive interactions (and some other limiting factors. This definition implies that NF is "larger" than NR, something that has been nearly universally accepted by ecologists. However, there have been few attempts at empirical tests. Here, we present a novel quantitative test using one-dimensional estimates of NF for 105 species of reptiles and amphibians, and estimates of NR obtained from ~1.4 x 104 field observations. To specify our test, we operationalize the original classification of niche types. Our results predominantly support the hypothesis that NF 'is larger' than NR and we highlight the theoretical and practical importance of quantifying niches.
Realization of OFDM modulation and demodulation for visible light communication based on FPGA
Wu, Chun-hui; Gao, Zong-yu; Li, Hong-lei; Chen, Xiong-bin; Mao, Xu-rui; Lu, Hui-min; Wang, Jian-ping; He, Lin; Cui, Shi-gang; Chen, Hong-da
2017-01-01
In order to ensure stable, correct and real-time high-speed transmission of indoor visible light communication (VLC), the key modulation and demodulation technologies of orthogonal frequency division multiplexing (OFDM) are studied in this paper. The time-domain synchronization, frequency synchronization and channel equalization of receiver are analyzed and optimized by utilizing short and long training preamble. Moreover, field programmable gate array (FPGA) development board (Xilinx Kintex-7) and Verilog hardware description language are used to realize the design of proposed OFDM-VLC system. Simulation and experiment both verify the feasibility of the hardware designs of this system. The proposed OFDM-based VLC system can process signal in real-time, which can be used in actual VLC application systems.
Realization of low-scattering metamaterial shell based on cylindrical wave expanding theory.
Wu, Xiaoyu; Hu, Chenggang; Wang, Min; Pu, Mingbo; Luo, Xiangang
2015-04-20
In this paper, we demonstrate the design of a low-scattering metamaterial shell with strong backward scattering reduction and a wide bandwidth at microwave frequencies. Low echo is achieved through cylindrical wave expanding theory, and such shell only contains one metamaterial layer with simultaneous low permittivity and permeability. Cut-wire structure is selected to realize the low electromagnetic (EM) parameters and low loss on the resonance brim region. The full-model simulations show good agreement with theoretical calculations, and illustrate that near -20dB reduction is achieved and the -10 dB bandwidth can reach up to 0.6 GHz. Compared with the cloak based on transformation electromagnetics, the design possesses advantage of simpler requirement of EM parameters and is much easier to be implemented when only backward scattering field is cared.
Final Report for the Virtual Reliability Realization System LDRD
Energy Technology Data Exchange (ETDEWEB)
DELLIN, THEODORE A.; HENDERSON, CHRISTOPHER L.; O' TOOLE, EDWARD J.
2000-12-01
Current approaches to reliability are not adequate to keep pace with the need for faster, better and cheaper products and systems. This is especially true in high consequence of failure applications. The original proposal for the LDRD was to look at this challenge and see if there was a new paradigm that could make reliability predictions, along with a quantitative estimate of the risk in that prediction, in a way that was faster, better and cheaper. Such an approach would be based on the underlying science models that are the backbone of reliability predictions. The new paradigm would be implemented in two software tools: the Virtual Reliability Realization System (VRRS) and the Reliability Expert System (REX). The three-year LDRD was funded at a reduced level for the first year ($120K vs. $250K) and not renewed. Because of the reduced funding, we concentrated on the initial development of the expertise system. We developed an interactive semiconductor calculation tool needed for reliability analyses. We also were able to generate a basic functional system using Microsoft Siteserver Commerce Edition and Microsoft Sequel Server. The base system has the capability to store Office documents from multiple authors, and has the ability to track and charge for usage. The full outline of the knowledge model has been incorporated as well as examples of various types of content.
Detrending the realized volatility in the global FX market
Schmidt, Anatoly B.
2009-05-01
There has been growing interest in realized volatility (RV) of financial assets that is calculated using intra-day returns. The choice of optimal time grid for these calculations is not trivial and generally requires analysis of RV dependence on the grid spacing (so-called RV signature). Typical RV signatures have a maximum at the finest time grid spacing available, which is attributed to the microstructure effects. This maximum decays into a plateau at lower frequencies, which implies (almost) stationary return variance. We found that the RV signatures in the modern global FX market may have no plateau or even have a maximum at lower frequencies. Simple averaging methods used to address the microstructure effects in equities have no practical effect on the FX RV signatures. We show that local detrending of the high-frequency FX rate samples yields RV signatures with a pronounced plateau. This implies that FX rates can be described with a Brownian motion having non-stationary trend and stationary variance. We point at a role of algorithmic trading as a possible cause of micro-trends in FX rates.
Government Support and Infrastructure: Realizing the value of collaborative work
Directory of Open Access Journals (Sweden)
Peter Levesque
2008-09-01
Full Text Available CCommunity-campus research has undergone significant growth over the last two decades. While there has been some support in the form of government programs, significant gaps remain. The identification of collaborative research – what Gibbons et al. (1994 called Mode Two, complementing more traditional Mode One research – necessitates a better understanding of the incentives and infrastructure needed to produce greater value from both modes of research production. This article presents an argument that research is fundamentally three questions: what, so what and now what. It further argues that while the system is good at producing data and information as well as interpretation and analysis, it is not quite so competent when it comes to decisions that produce value beyond products, programs and sometimes, policies. This article introduces concepts related to knowledge mobilization and the need for dedicated incentives and infrastructure to realize the value of collaborative work. It introduces a taxonomy of legal government powers to protect and promote public health that may be adapted to the creation of support for community-campus research. This article suggests that government support for collaborative research must be built from arguments that demonstrate the added value that comes from engaging in these processes. It further argues that this is essentially a political process that must include explicit and open conversations across sectors and stakeholders.
Realization of a Complex Control & Diagnosis System on Simplified Hardware
Stetter, R.; Swamy Prasad, M.
2015-11-01
Energy is an important factor in today's industrial environment. Pump systems account for about 20% of the total industrial electrical energy consumption. Several studies show that with proper monitoring, control and maintenance, the efficiency of pump systems can be increased. Controlling pump systems with intelligent systems can help to reduce a pump's energy consumption by up to one third of its original consumption. The research in this paper was carried out in the scope of a research project which involves modelling and simulation of pump systems. This paper focuses on the future implementation of modelling capabilities in PLCs (programmable logic controllers). The whole project aims to use a pump itself as the sensor rather than introducing external sensors into the system, which would increase the cost considerably. One promising approach for an economic and robust industrial implementation of this intelligence is the use of PLCs. PLCs can be simulated in multiple ways; in this project, Codesys was chosen for several reasons which are explained in this paper. The first part of this paper explains the modelling of a pump itself, the process load of the asynchronous motor with a control system, and the simulation possibilities of the motor in Codesys. The second part describes the simulation and testing of a system realized. The third part elaborates the Codesys system structure and interfacing of the system with external files. The final part consists of comparing the result with an earlier Matlab/SIMULINK model and original test data.
Mechanical characterization of copper coatings realized by thermal spraying
International Nuclear Information System (INIS)
Gassot, H.; Junquera, T.; Legoff, A.; Lescornet, J.C.; Ji, V.; Grandsire, L.
2000-11-01
The stiffening of superconducting cavities is required to assure mechanical stability. The stiffening method used for the tesla test facility (TTF) is non-sufficient for the Tesla project (TeV energy superconducting linear accelerator). A new method has been developed, this method is based on the thermal spraying of a copper coating on the backside of a niobium cavity, simulations show a promising future for this technique. This report presents the structure, the behaviour and the characteristics of a copper coating realized by thermal spraying. The elastic properties of the coating plays an important role for the stiffening of the cavity. A stress analysis has been achieved on samples by using X-ray diffraction, this technique is the only one that takes into account anisotropy effects. From the results of tensile tests it appears that copper coatings are very fragile and far less ductile than massive metal, it is mainly due to the strong oxidation rate of the coating (about 12%). The hardness of a coating is 20% higher than of massive copper. Other tensile tests have been performed to evaluate the adherence of the coating to the niobium, an adherence force of 50 MPa has been deduced from testing. (A.C.)