Projective symmetry group classification of chiral spin liquids
Bieri, Samuel; Lhuillier, Claire; Messio, Laura
2016-03-01
We present a general review of the projective symmetry group classification of fermionic quantum spin liquids for lattice models of spin S =1 /2 . We then introduce a systematic generalization of the approach for symmetric Z2 quantum spin liquids to the one of chiral phases (i.e., singlet states that break time reversal and lattice reflection, but conserve their product). We apply this framework to classify and discuss possible chiral spin liquids on triangular and kagome lattices. We give a detailed prescription on how to construct quadratic spinon Hamiltonians and microscopic wave functions for each representation class on these lattices. Among the chiral Z2 states, we study the subset of U(1) phases variationally in the antiferromagnetic J1-J2-Jd Heisenberg model on the kagome lattice. We discuss static spin structure factors and symmetry constraints on the bulk spectra of these phases.
Symmetry breaking in the opinion dynamics of a multi-group project organization
Zhu, Zhen-Tao; Zhou, Jing; Li, Ping; Chen, Xing-Guang
2012-10-01
A bounded confidence model of opinion dynamics in multi-group projects is presented in which each group's opinion evolution is driven by two types of forces: (i) the group's cohesive force which tends to restore the opinion back towards the initial status because of its company culture; and (ii) nonlinear coupling forces with other groups which attempt to bring opinions closer due to collaboration willingness. Bifurcation analysis for the case of a two-group project shows a cusp catastrophe phenomenon and three distinctive evolutionary regimes, i.e., a deadlock regime, a convergence regime, and a bifurcation regime in opinion dynamics. The critical value of initial discord between the two groups is derived to discriminate which regime the opinion evolution belongs to. In the case of a three-group project with a symmetric social network, both bifurcation analysis and simulation results demonstrate that if each pair has a high initial discord, instead of symmetrically converging to consensus with the increase of coupling scale as expected by Gabbay's result (Physica A 378 (2007) p. 125 Fig. 5), project organization (PO) may be split into two distinct clusters because of the symmetry breaking phenomenon caused by pitchfork bifurcations, which urges that apart from divergence in participants' interests, nonlinear interaction can also make conflict inevitable in the PO. The effects of two asymmetric level parameters are tested in order to explore the ways of inducing dominant opinion in the whole PO. It is found that the strong influence imposed by a leader group with firm faith on the flexible and open minded follower groups can promote the formation of a positive dominant opinion in the PO.
Symmetry breaking in the opinion dynamics of a multi-group project organization
Zhu Zhen-Tao; Zhou Jing; Li Ping; Chen Xing-Guang
2012-01-01
A bounded confidence model of opinion dynamics in multi-group projects is presented in which each group's opinion evolution is driven by two types of forces:(i) the group's cohesive force which tends to restore the opinion back towards the initial status because of its company culture; and (ii) nonlinear coupling forces with other groups which attempt to bring opinions closer due to collaboration willingness.Bifurcation analysis for the case of a two-group project shows a cusp catastrophe phenomenon and three distinctive evolutionary regimes,i.e.,a deadlock regime,a convergence regime,and a bifurcation regime in opinion dynamics.The critical value of initial discord between the two groups is derived to discriminate which regime the opinion evolution belongs to.In the case of a three-group project with a symmetric social network,both bifurcation analysis and simulation results demonstrate that if each pair has a high initial discord,instead of symmetrically converging to consensus with the increase of coupling scale as expected by Gabbay's result (Physica A 378 (2007) p.125 Fig.5),project organization (PO) may be split into two distinct clusters because of the symmetry breaking phenomenon caused by pitchfork bifurcations,which urges that apart from divergence in participants' interests,nonlinear interaction can also make conflict inevitable in the PO.The effects of two asymmetric level parameters are tested in order to explore the ways of inducing dominant opinion in the whole PO.It is found that the strong influence imposed by a leader group with firm faith on the flexible and open minded follower groups can promote the formation of a positive dominant opinion in the PO.
Farmer, David W
1995-01-01
In most mathematics textbooks, the most exciting part of mathematics-the process of invention and discovery-is completely hidden from the reader. The aim of Groups and Symmetry is to change all that. By means of a series of carefully selected tasks, this book leads readers to discover some real mathematics. There are no formulas to memorize; no procedures to follow. The book is a guide: Its job is to start you in the right direction and to bring you back if you stray too far. Discovery is left to you. Suitable for a one-semester course at the beginning undergraduate level, there are no prerequ
Symmetry and group theory in chemistry
Ladd, M
1998-01-01
A comprehensive discussion of group theory in the context of molecular and crystal symmetry, this book covers both point-group and space-group symmetries.Provides a comprehensive discussion of group theory in the context of molecular and crystal symmetryCovers both point-group and space-group symmetriesIncludes tutorial solutions
Fuchigami, Kei; Schrandt, Matthew; Miessler, Gary L.
2016-01-01
A hands-on symmetry project is proposed as an innovative way of teaching point groups to undergraduate chemistry students. Traditionally, courses teaching symmetry require students to identify the point group of a given object. This project asks the reverse: students are instructed to identify an object that matches each point group. Doing so…
Parity-time symmetry broken by point-group symmetry
Fernández, Francisco M., E-mail: fernande@quimica.unlp.edu.ar; Garcia, Javier [INIFTA (UNLP, CCT La Plata-CONICET), División Química Teórica, Blvd. 113 S/N, Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina)
2014-04-15
We discuss a parity-time (PT) symmetric Hamiltonian with complex eigenvalues. It is based on the dimensionless Schrödinger equation for a particle in a square box with the PT-symmetric potential V(x, y) = iaxy. Perturbation theory clearly shows that some of the eigenvalues are complex for sufficiently small values of |a|. Point-group symmetry proves useful to guess if some of the eigenvalues may already be complex for all values of the coupling constant. We confirm those conclusions by means of an accurate numerical calculation based on the diagonalization method. On the other hand, the Schrödinger equation with the potential V(x, y) = iaxy{sup 2} exhibits real eigenvalues for sufficiently small values of |a|. Point group symmetry suggests that PT-symmetry may be broken in the former case and unbroken in the latter one.
Symmetry and group theory throughout physics
Villain J.
2012-03-01
Full Text Available As noticed in 1884 by Pierre Curie [1], physical properties of matter are tightly related to the kind of symmetry of the medium. Group theory is a systematic tool, though not always easy to handle, to exploit symmetry properties, for instance to find the eigenvectors and eigenvalues of an operator. Certain properties (optical activity, piezoelectricity are forbidden in molecules or crystals of high symmetry. A few theorems (Noether, Goldstone establish general relations between physical properties and symmetry. Applications of group theory to condensed matter physics, elementary particle physics, quantum mechanics, electromagnetism are reviewed. Group theory is not only a tool, but also a beautiful construction which casts insight into natural phenomena.
Continuous point symmetries in Group Field Theories
Kegeles, Alexander
2016-01-01
We discuss the notion of symmetries in non-local field theories characterized by integro-differential equation of motion, from a geometric perspective. We then focus on Group Field Theory (GFT) models of quantum gravity. We provide a general analysis of their continuous point symmetry transformations, including the generalized conservation laws following from them, and apply it to several GFT models of interest to current research.
Quregisters, Symmetry Groups and Clifford Algebras
Cervantes, D.; Morales-Luna, G.
2016-03-01
Natural one-to-one and two-to-one homomorphisms from SO(3) into SU(2) are built conventionally, and the collection of qubits, is identified with a subgroup of SU(2). This construction is suitable to be extended to corresponding tensor powers. The notions of qubits, quregisters and qugates are translated into the language of symmetry groups. The corresponding elements to entangled states in the tensor product of Hilbert spaces reflect entanglement properties as well, and in this way a notion of entanglement is realised in the tensor product of symmetry groups.
Group Parametrized Tunneling and Local Symmetry Conditions
Harter, William; Mitchell, Justin
2010-06-01
Recently, Hougen showed an ad hoc symmetry-based parameterization scheme for analyzing tunneling dynamics and high resolution spectra of fluxional molecular structure similar to S-parameter analysis of superfine structure in SF_6 or NH_3 maser inversion dynamics by Feynman et.al. The problem is that ad hoc parametrization, like path integration in general, can lead to logjams of parameters or ``paths'' with no way to pick out the relevant ones. We show a way to identify and use relevant parameters for a tunneling Hamiltonian H having global G-symmetry-defined bases by first expressing H as a linear combination bar γ ^i {bar g}_i of operators in dual symmetry group bar G. The coefficients bar γ ^i are parameters that define a complete set of allowed paths for any H with G-symmetry and are related thru spectral decomposition of G to eigensolutions of H. Quantum G vs.bar G duality generalizes lab -vs. -body and state -vs. -particle. The number of relevant bar γ ^i-parameters is reduced if a system tends to stick in states of a local symmetry subgroup LsubsetG so the H spectrum forms level clusters labeled by induced representations d(ℓ)(L)\\uparrowG. A cluster-(ℓ) has one E(epsilon)-level labeled by G species (epsilon) for each L species (ℓ) in Depsilon(G)downarrowL by Frobenius reciprocity. Then we apply local symmetry conditions to each irrep Depsilon(bar γ ^i {bar g}_i) that has already been reduced with respect to local symmetry L. This amounts to setting each off-diagonal component Dj,kepsilon(H) to zero. Local symmetry conditions may tell which bar γ ^i-parameters are redundant or zero and directly determine d(ℓ)\\uparrowG tunneling matrix eigenvalues that give E(epsilon)-levels as well as eigenvectors. Otherwise one may need to choose a particular localizing subgroup chain LsubsetL_1subsetL_2...G and further reduce the number of path parameters to facilitate spectral fitting. J.T. Hougen, 2009 MSS RJ01, {J Mol Spect 123, 197 (1987) W.G. Harter and
Holonomy groups and W-symmetries
Howe, Paul S
1993-01-01
Irreducible sigma models, i.e. those for which the partition function does not factorise, are defined on Riemannian spaces with irreducible holonomy groups. These special geometries are characterised by the existence of covariantly constant forms which in turn give rise to symmetries of the supersymmetric sigma model actions. The Poisson bracket algebra of the corresponding currents is a W-algebra. Extended supersymmetries arise as special cases.
Discrete flavour symmetries from the Heisenberg group
Floratos, E. G.; Leontaris, G. K.
2016-04-01
Non-abelian discrete symmetries are of particular importance in model building. They are mainly invoked to explain the various fermion mass hierarchies and forbid dangerous superpotential terms. In string models they are usually associated to the geometry of the compactification manifold and more particularly to the magnetised branes in toroidal compactifications. Motivated by these facts, in this note we propose a unified framework to construct representations of finite discrete family groups based on the automorphisms of the discrete and finite Heisenberg group. We focus in particular, on the PSL2 (p) groups which contain the phenomenologically interesting cases.
Discrete Flavour Symmetries from the Heisenberg Group
Floratos, E G
2015-01-01
Non-abelian discrete symmetries are of particular importance in model building. They are mainly invoked to explain the various fermion mass hierarchies and forbid dangerous superpotential terms. In string models they are usually associated to the geometry of the compactification manifold and more particularly to the magnetised branes in toroidal compactifications. Motivated by these facts, in this note we propose a unified framework to construct representations of finite discrete family groups based on the automorphisms of the discrete and finite Heisenberg group. We focus in particular in the $PSL_2(p)$ groups which contain the phenomenologically interesting cases.
Lie symmetries of the geodesic equations and projective collineations
Tsamparlis, Michael; Paliathanasis, Andronikos, E-mail: mtsampa@phys.uoa.g, E-mail: paliathanasis@gmail.co [Department of Physics, Section Astrophysics Astronomy Mechanics, University of Athens, University of Athens, Zografos 15783, Athens (Greece)
2009-10-01
We study the Lie symmetries of the geodesic equations in a Riemannian space and show that they coincide with the projective symmetries of the Riemannian metric. We apply the result to the spaces of constant curvature.
Inverse Symmetry Breaking and the Exact Renormalization Group
Pietroni, M; Tetradis, N
1997-01-01
We discuss the question of inverse symmetry breaking at non-zero temperature using the exact renormalization group. We study a two-scalar theory and concentrate on the nature of the phase transition during which the symmetry is broken. We also examine the persistence of symmetry breaking at temperatures higher than the critical one.
The symmetry groups of bifurcations of integrable Hamiltonian systems
Orlova, E I [M. V. Lomonosov Moscow State University, Faculty of Mechanics and Mathematics, Moscow (Russian Federation)
2014-11-30
Two-dimensional atoms are investigated; these are used to code bifurcations of the Liouville foliations of nondegenerate integrable Hamiltonian systems. To be precise, the symmetry groups of atoms with complexity at most 3 are under study. Atoms with symmetry group Z{sub p}⊕Z{sub q} are considered. It is proved that Z{sub p}⊕Z{sub q} is the symmetry group of a toric atom. The symmetry groups of all nonorientable atoms with complexity at most 3 are calculated. The concept of a geodesic atom is introduced. Bibliography: 9 titles.
Lie symmetries and differential galois groups of linear equations
Oudshoorn, W.R.; Put, M. van der
2002-01-01
For a linear ordinary differential equation the Lie algebra of its infinitesimal Lie symmetries is compared with its differential Galois group. For this purpose an algebraic formulation of Lie symmetries is developed. It turns out that there is no direct relation between the two above objects. In co
Symmetry, Group Theory, and the Physical Properties of Crystals
Powell, Richard C.
The intent of this book is to demonstrate the importance of symmetry in determining the properties of solids and the power of using group theory and tensor algebra to elucidate these properties. It is not meant to be a comprehensive text on solid state physics, so many important aspects of condensed matter physics not related to symmetry are not covered here. The book begins by discussing the concepts of symmetry relevant to crystal structures. This is followed by a summary of the basics of group theory and how it is applied to quantum mechanics. Next is a discussion of the description of the macroscopic properties of crystals by tensors and how symmetry determines the form of these tensors. The basic concepts covered in these early chapters are then applied to a series of different examples. There is a discussion of the use of point symmetry in the crystal field theory treatment of point defects in solids. Next is a discussion of crystal symmetry in determining the optical properties of solids, followed by a chapter on the nonlinear optical properties of solids. Then the role of symmetry in treating lattice vibrations is described. The last chapter discusses the effects of translational symmetry on electronic energy bands in solids.
Full Non-Rigid Group and Symmetry of Dimethyltrichlorophosphorus
ASHRAFI; AliReza
2005-01-01
In this work, a simple method is described, by means of which it is possible to calculate character tables for the symmetry group of molecules consisting of a number of NH3 groups attached to a rigid framework. The full non-rigid group (f-NRG) of dimethyltrichlorophosphorus with the symmetry group D3h was studied. It has been proven that it is a group of order 216 with 27 conjugacy classes and its character table computed. Finally, the Permutation-lnversion group of this molecule was calculated.
Using Group Theory to Obtain Eigenvalues of Nonsymmetric Systems by Symmetry Averaging
Marion L. Ellzey
2009-08-01
Full Text Available If the Hamiltonian in the time independent Schrödinger equation, HΨ = EΨ, is invariant under a group of symmetry transformations, the theory of group representations can help obtain the eigenvalues and eigenvectors of H. A finite group that is not a symmetry group of H is nevertheless a symmetry group of an operator Hsym projected from H by the process of symmetry averaging. In this case H = Hsym + HR where HR is the nonsymmetric remainder. Depending on the nature of the remainder, the solutions for the full operator may be obtained by perturbation theory. It is shown here that when H is represented as a matrix [H] over a basis symmetry adapted to the group, the reduced matrix elements of [Hsym] are simple averages of certain elements of [H], providing a substantial enhancement in computational efficiency. A series of examples are given for the smallest molecular graphs. The first is a two vertex graph corresponding to a heteronuclear diatomic molecule. The symmetrized component then corresponds to a homonuclear system. A three vertex system is symmetry averaged in the first case to Cs and in the second case to the nonabelian C3v. These examples illustrate key aspects of the symmetry-averaging process.
Xi-Zhong, Liu
2012-01-01
In this paper, We derive the symmetry group theorem to the Lin-Tsien equation by using the modified CK's direct method, from which we obtain the corresponding symmetry group. More importantly, conservation laws corresponding to the Kac-Moody-Virasoro symmetry algebra of Lin-Tsien equation is obtained up to second order group invariants.
Partial symmetry, reflection monoids and Coxeter groups
Everitt, Brent; Fountain, John
2008-01-01
This is the first of a series of papers in which we initiate and develop the theory of reflection monoids, motivated by the theory of reflection groups. The main results identify a number of important inverse semigroups as reflection monoids, introduce new examples, and determine their orders.
Determining Symmetry Properties of Gravitational Fields of Terrestrial Group Planets
R.A. Kascheev
2016-09-01
Full Text Available Numerous models of gravity fields of the Solar system bodies have been constructed recently owing to successful space missions. These models are sets of harmonic coefficients of gravity potential expansion in series of spherical functions, which is Laplace series. The sets of coefficients are different in quantity of numerical parameters, sources and composition of the initial observational data, methods to obtain and process them, and, consequently, in a variety of properties and accuracy characteristics. For this reason, the task of comparison of different models of celestial bodies considered in the paper is of interest and relevant. The main purpose of this study is comparison of the models of gravitational potential of the Earth, Moon, Mars, and Venus with the quantitative criteria of different types of symmetries developed by us. It is assumed that some particular symmetry of the density distribution function of the planetary body causes similar symmetry of its gravitational potential. The symmetry of gravitational potential, in its turn, imposes additional conditions (restrictions, which must be satisfied by the harmonic coefficients. The paper deals with seven main types of symmetries: central, axial, two symmetries specular relative to the equatorial planes and prime meridian, as well as three rotational symmetries (at π angle around the coordinate system axes. According to the results of calculations carried out for the Earth, Moon, Mars, and Venus, the values of the criteria vary considerably for different types of symmetries and for different planets. It means that the specific value of each criterion corresponding to a particular celestial body is indicative of the properties and internal structure characteristics of the latter and, therefore, it can be used as a tool for comparative planetology. On the basis of the performed calculations, it is possible to distinguish two groups of celestial bodies having similar properties of
Exotic Newton-Hooke group, noncommutative plane and superconformal symmetry
Alvarez, Pedro D
2009-01-01
In this thesis we have studied some systems with exotic symmetries, which are a peculiarity in 2+1 space-time dimensions. Coded in the exotic structure appears noncommutative coordinates and a phases structure. This kind of systems has attracted attention from different areas of physics independently. Among them we can mention: theory of ray representations of Lie groups, anyons physics, some condensed matter systems, for instance the quantum Hall effect, planar gauge and gravitation theories, noncommutative field theory, noncommutative geometry and noncommutative quantum mechanics. We will focus our study in some topics on exotic nonrelativistic symmetries, such as the exotic Newton-Hooke group, the relation between the systems of exotic Newton-Hooke and the noncommutative Landau problem and the symmetries of noncommutative Landau problem, its conformal and supersymmetric extensions. The exotic Newton-Hooke group correspond to the nonrelativistic limit of the de Sitter groups, and has as a particular case (f...
Renormalisation group improved leptogenesis in family symmetry models
Cooper, Iain K., E-mail: ikc1g08@soton.ac.uk [School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ (United Kingdom); King, Stephen F., E-mail: king@soton.ac.uk [School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Luhn, Christoph, E-mail: christoph.luhn@durham.ac.uk [School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Institute for Particle Physics Phenomenology, University of Durham, Durham, DH1 3LE (United Kingdom)
2012-06-11
We study renormalisation group (RG) corrections relevant for leptogenesis in the case of family symmetry models such as the Altarelli-Feruglio A{sub 4} model of tri-bimaximal lepton mixing or its extension to tri-maximal mixing. Such corrections are particularly relevant since in large classes of family symmetry models, to leading order, the CP violating parameters of leptogenesis would be identically zero at the family symmetry breaking scale, due to the form dominance property. We find that RG corrections violate form dominance and enable such models to yield viable leptogenesis at the scale of right-handed neutrino masses. More generally, the results of this paper show that RG corrections to leptogenesis cannot be ignored for any family symmetry model involving sizeable neutrino and {tau} Yukawa couplings.
Resource Letter SP-2: Symmetry and Group Theory in Physics.
Rosen, Joe
1981-01-01
Presents listings of selected reference materials relevant to symmetry and group theory in college physics and chemistry. Entries are classified according to a scheme involving 34 subject areas divided into four major groups. Comments on these materials and suggestions for future topics will be welcomed. (Author/SK)
Hypersurfaces in Pn with 1-parameter symmetry groups II
Plessis, Andrew du; Wall, C.T.C.
2010-01-01
We assume V a hypersurface of degree d in with isolated singularities and not a cone, admitting a group G of linear symmetries. In earlier work we treated the case when G is semi-simple; here we analyse the unipotent case. Our first main result lists the possible groups G. In each case we discuss...
Symmetry group analysis of an ideal plastic flow
Lamothe, Vincent
2011-01-01
In this paper, we study the Lie point symmetry group of a system describing an ideal plastic plane flow in two dimensions in order to find analytical solutions. The infinitesimal generators that span the Lie algebra for this system are obtained. We completely classify the subalgebras of up to codimension two in conjugacy classes under the action of the symmetry group. Based on invariant forms, we use Ansatzes to compute symmetry reductions in such a way that the obtained solutions cover simultaneously many invariant and partially invariant solutions. We calculate solutions of the algebraic, trigonometric, inverse trigonometric and elliptic type. Some solutions depending on one or two arbitrary functions of one variable have also been found. In some cases, the shape of a potentially feasible extrusion die corresponding to the solution is deduced. These tools could be used to thin, curve, undulate or shape a ring in an ideal plastic material.
On the construction of double group molecular symmetry functions
Visscher, L
1996-01-01
A new procedure for constructing double group symmetry functions is presented. Using this method integrals over Hermitian operators can become real quantities, even though the integrand and the functions themselves are complex. This is especially of interest to 4-component relativistic methods that
Flack, H D; Wondratschek, H; Hahn, T; Abrahams, S C
2000-01-01
The definition of 'symmetry element' given in the Report of the IUCr Ad-Hoc Committee on the Nomenclature of Symmetry by de Wolff et al. [Acta Cryst. (1989). A45, 494-499] is shown to contain an ambiguity in the case of space groups P6/m, P6/mmm, P6/mcc and point groups 6/m and 6/mmm. The ambiguity is removed by redefining the 'geometric element' as a labelled geometric item in which the label is related to the rotation angle of the rotation or rotoinversion symmetry operation. The complete set of different types of glide plane is shown to contain three more than the 15 that are illustrated in the 1992 Report by de Wolff et al. [Acta Cryst. (1992). A48, 727-732].
Symmetries of KdV and loop groups
Schiff, J; Schiff, Jeremy; Sci, Comp
1996-01-01
A simple version of the Segal-Wilson map from the SL(2,C) loop group to a class of solutions of the KdV hierarchy is given, clarifying certain aspects of this map. It is explained how the known symmetries, including Backlund transformations, of KdV arise from simple, field independent, actions on the loop group. A variety of issues in understanding the algebraic structure of Backlund transformations are thus resolved.
Space Group Symmetry Fractionalization in a Chiral Kagome Heisenberg Antiferromagnet.
Zaletel, Michael P; Zhu, Zhenyue; Lu, Yuan-Ming; Vishwanath, Ashvin; White, Steven R
2016-05-13
The anyonic excitations of a spin liquid can feature fractional quantum numbers under space group symmetries. Detecting these fractional quantum numbers, which are analogs of the fractional charge of Laughlin quasiparticles, may prove easier than the direct observation of anyonic braiding and statistics. Motivated by the recent numerical discovery of spin-liquid phases in the kagome Heisenberg antiferromagnet, we theoretically predict the pattern of space group symmetry fractionalization in the kagome lattice SO(3)-symmetric chiral spin liquid. We provide a method to detect these fractional quantum numbers in finite-size numerics which is simple to implement in the density matrix renormalization group. Applying these developments to the chiral spin liquid phase of a kagome Heisenberg model, we find perfect agreement between our theoretical prediction and numerical observations.
Clark, R. A.; Lewis, M
1985-09-01
This report is a summary of progress in the Surry Steam Generator Group Project for 1984. Information is presented on the analysis of two baseline eddy current inspections of the generator. Round robin series of tests using standard in-service inspection techniques are described along with some preliminary results. Observations are reported of degradation found on tubing specimens removed from the generator, and on support plates characterized in-situ. Residual stresses measured on a tubing specimen are reported. Two steam generator repair demonstrations are described; one for antivibration bar replacement, and one on tube repair methods. Chemical analyses are shown for sludge samples removed from above the tube sheet.
The analysis of crystallographic symmetry types in finite groups
Sani, Atikah Mohd; Sarmin, Nor Haniza; Adam, Nooraishikin; Zamri, Siti Norziahidayu Amzee
2014-06-01
Undeniably, it is human nature to prefer objects which are considered beautiful. Most consider beautiful as perfection, hence they try to create objects which are perfectly balance in shape and patterns. This creates a whole different kind of art, the kind that requires an object to be symmetrical. This leads to the study of symmetrical objects and pattern. Even mathematicians and ethnomathematicians are very interested with the essence of symmetry. One of these studies were conducted on the Malay traditional triaxial weaving culture. The patterns derived from this technique are symmetrical and this allows for further research. In this paper, the 17 symmetry types in a plane, known as the wallpaper groups, are studied and discussed. The wallpaper groups will then be applied to the triaxial patterns of food cover in Malaysia.
Characterizing symmetries in a projected entangled pair state
Perez-Garcia, D; Gonzalez-Guillen, C E [Departamento Analisis Matematico and IMI, Universidad Complutense de Madrid, 28040 Madrid (Spain); Sanz, M; Cirac, J I [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Str. 1, 85748 Garching (Germany); Wolf, M M [Niels Bohr Institute, Blegdamsvej 17, 2100 Copenhagen (Denmark)], E-mail: dperez@mat.ucm.es
2010-02-15
We show that two different tensors defining the same translational invariant injective projected entangled pair state (PEPS) in a square lattice must be the same up to a trivial gauge freedom. This allows us to characterize the existence of any local or spatial symmetry in the state. As an application of these results we prove that a SU(2) invariant PEPS with half-integer spin cannot be injective, which can be seen as a Lieb-Shultz-Mattis theorem in this context. We also give the natural generalization for U(1) symmetry in the spirit of Oshikawa-Yamanaka-Affleck, and show that a PEPS with Wilson loops cannot be injective.
Symmetry an introduction to group theory and its applications
McWeeny, R
2013-01-01
Symmetry: An Introduction to Group Theory and its Application is an eight-chapter text that covers the fundamental bases, the development of the theoretical and experimental aspects of the group theory. Chapter 1 deals with the elementary concepts and definitions, while Chapter 2 provides the necessary theory of vector spaces. Chapters 3 and 4 are devoted to an opportunity of actually working with groups and representations until the ideas already introduced are fully assimilated. Chapter 5 looks into the more formal theory of irreducible representations, while Chapter 6 is concerned largely w
Quantum group symmetry and q-tensor algebras
Biedenharn, Lawrence Christian
1995-01-01
Quantum groups are a generalization of the classical Lie groups and Lie algebras and provide a natural extension of the concept of symmetry fundamental to physics. This monograph is a survey of the major developments in quantum groups, using an original approach based on the fundamental concept of a tensor operator. Using this concept, properties of both the algebra and co-algebra are developed from a single uniform point of view, which is especially helpful for understanding the noncommuting co-ordinates of the quantum plane, which we interpret as elementary tensor operators. Representations
Generation of symmetry coordinates for crystals using multiplier representations of the space groups
Hansen, Flemming Yssing
1978-01-01
Symmetry coordinates play an important role in the normal-mode calculations of crystals. It is therefore of great importance to have a general method, which may be applied for any crystal at any wave vector, to generate these. The multiplier representations of the space groups as given by Kovalev...... and the projection-operator technique provide a basis for such a method. The method is illustrated for the nonsymmorphic D36 space group, and the theoretical background for the representations of space groups in general is reviewed and illustrated on the example above. It is desirable to perform the projection...... of symmetry coordinates in such a way that they may be used for as many wave vectors as possible. We discuss how to achieve this goal. The detailed illustrations should make it simple to apply the theory in any other case....
Flavor Symmetry and Galois Group of Elliptic Curves
Hattori, Chuichiro; Matsuoka, Takeo; Nakanishi, Kenichi
2009-01-01
A new approach to the generation structure of fermions is proposed. We consider a brane configuration in which the brane intersection yields a two-torus in the extra space. It is assumed that the two-torus is discretized and is given by the torsion points of the elliptic curve over Q . We direct our attention to the arithmetic structure of the elliptic curve with complex multiplication (CM). In our approach the flavor symmetry including the R-parity has its origin in the Galois group of elliptic curves with CM. We study the possible types of the Galois group. The Galois group is shown to be an extension of Z_2 by some abelian group. A phenomenologically viable example of the Galois group is presented, in which the characteristic texture of fermion masses and mixings is reproduced and the mixed-anomaly conditions are satisfied.
New Insights into Viral Architecture via Affine Extended Symmetry Groups
T. Keef
2008-01-01
Full Text Available Since the seminal work of Caspar and Klug on the structure of the protein containers that encapsulate and hence protect the viral genome, it has been recognized that icosahedral symmetry is crucial for the structural organization of viruses. In particular, icosahedral symmetry has been invoked in order to predict the surface structures of viral capsids in terms of tessellations or tilings that schematically encode the locations of the protein subunits in the capsids. Whilst this approach is capable of predicting the relative locations of the proteins in the capsids, a prediction on the relative sizes of different virus particles in a family cannot be made. Moreover, information on the full 3D structure of viral particles, including the tertiary structures of the capsid proteins and the organization of the viral genome within the capsid are inaccessible with their approach. We develop here a mathematical framework based on affine extensions of the icosahedral group that allows us to address these issues. In particular, we show that the relative radii of viruses in the family of Polyomaviridae and the material boundaries in simple RNA viruses can be determined with our approach. The results complement Caspar and Klug's theory of quasi-equivalence and provide details on virus structure that have not been accessible with previous methods, implying that icosahedral symmetry is more important for virus architecture than previously appreciated.
Jiménez-Hoyos, Carlos A; Scuseria, Gustavo E
2013-01-01
Recent work from our research group has demonstrated that symmetry-projected Hartree--Fock (HF) methods provide a compact representation of molecular ground state wavefunctions based on a superposition of non-orthogonal Slater determinants. The symmetry-projected ansatz can account for static correlations in a computationally efficient way. Here we present a variational extension of this methodology applicable to excited states of the same symmetry as the ground state. Benchmark calculations on the C$_2$ dimer with a modest basis set, which allows comparison with full configuration interaction results, indicate that this extension provides a high quality description of the low-lying spectrum for the entire dissociation profile. We apply the same methodology to obtain the full low-lying vertical excitation spectrum of formaldehyde, in good agreement with available theoretical and experimental data, as well as to a challenging model $C_{2v}$ insertion pathway for BeH$_2$. The variational excited state methodolo...
Duality, Gauge Symmetries, Renormalization Groups and the BKT Transition
José, Jorge V.
2017-03-01
In this chapter, I will briefly review, from my own perspective, the situation within theoretical physics at the beginning of the 1970s, and the advances that played an important role in providing a solid theoretical and experimental foundation for the Berezinskii-Kosterlitz-Thouless theory (BKT). Over this period, it became clear that the Abelian gauge symmetry of the 2D-XY model had to be preserved to get the right phase structure of the model. In previous analyses, this symmetry was broken when using low order calculational approximations. Duality transformations at that time for two-dimensional models with compact gauge symmetries were introduced by José, Kadanoff, Nelson and Kirkpatrick (JKKN). Their goal was to analyze the phase structure and excitations of XY and related models, including symmetry breaking fields which are experimentally important. In a separate context, Migdal had earlier developed an approximate Renormalization Group (RG) algorithm to implement Wilson’s RG for lattice gauge theories. Although Migdal’s RG approach, later extended by Kadanoff, did not produce a true phase transition for the XY model, it almost did asymptotically in terms of a non-perturbative expansion in the coupling constant with an essential singularity. Using these advances, including work done on instantons (vortices), JKKN analyzed the behavior of the spin-spin correlation functions of the 2D XY-model in terms of an expansion in temperature and vortex-pair fugacity. Their analysis led to a perturbative derivation of RG equations for the XY model which are the same as those first derived by Kosterlitz for the two-dimensional Coulomb gas. JKKN’s results gave a theoretical formulation foundation and justification for BKT’s sound physical assumptions and for the validity of their calculational approximations that were, in principle, strictly valid only at very low temperatures, away from the critical TBKT temperature. The theoretical predictions were soon tested
Duality, Gauge Symmetries, Renormalization Groups and the BKT Transition
José, Jorge V.
2013-06-01
In this chapter, I will briefly review, from my own perspective, the situation within theoretical physics at the beginning of the 1970s, and the advances that played an important role in providing a solid theoretical and experimental foundation for the Berezinskii-Kosterlitz-Thouless theory (BKT). Over this period, it became clear that the Abelian gauge symmetry of the 2D-XY model had to be preserved to get the right phase structure of the model. In previous analyses, this symmetry was broken when using low order calculational approximations. Duality transformations at that time for two-dimensional models with compact gauge symmetries were introduced by José, Kadanoff, Nelson and Kirkpatrick (JKKN). Their goal was to analyze the phase structure and excitations of XY and related models, including symmetry breaking fields which are experimentally important. In a separate context, Migdal had earlier developed an approximate Renormalization Group (RG) algorithm to implement Wilson's RG for lattice gauge theories. Although Migdal's RG approach, later extended by Kadanoff, did not produce a true phase transition for the XY model, it almost did asymptotically in terms of a non-perturbative expansion in the coupling constant with an essential singularity. Using these advances, including work done on instantons (vortices), JKKN analyzed the behavior of the spin-spin correlation functions of the 2D XY-model in terms of an expansion in temperature and vortex-pair fugacity. Their analysis led to a perturbative derivation of RG equations for the XY model which are the same as those first derived by Kosterlitz for the two-dimensional Coulomb gas. JKKN's results gave a theoretical formulation foundation and justification for BKT's sound physical assumptions and for the validity of their calculational approximations that were, in principle, strictly valid only at very low temperatures, away from the critical TBKT temperature. The theoretical predictions were soon tested
Gauged Flavor Group with Left-Right Symmetry
Guadagnoli, Diego; Sung, Ilmo
2011-01-01
We construct an anomaly-free extension of the left-right symmetric model, where the maximal flavor group is gauged and anomaly cancellation is guaranteed by adding new vectorlike fermion states. We address the question of the lowest allowed flavor symmetry scale consistent with data. Because of the mechanism recently pointed out by Grinstein et al. tree-level flavor changing neutral currents turn out to play a very weak constraining role. The same occurs, in our model, for electroweak precision observables. The main constraint turns out to come from WR-mediated flavor changing neutral current box diagrams, primarily K - Kbar mixing. In the case where discrete parity symmetry is present at the TeV scale, this constraint implies lower bounds on the mass of vectorlike fermions and flavor bosons of 5 and 10 TeV respectively. However, these limits are weakened under the condition that only SU(2)_R x U(1)_{B-L} is restored at the TeV scale, but not parity. For example, assuming the SU(2) gauge couplings in the rati...
Symmetries and Group-Invariant Solutions for Transonic Pressure-Gradient Equations
王丽真; 黄晴
2011-01-01
Lie symmetry group method is applied to study the transonic pressure-gradient equations in two-dimensional space. Its symmetry groups and corresponding optimal systems are determined, and several classes of irrotational groupinvariant solutions associated to the symmetries are obtained and special case of one-dimensional rarefaction wave is found.
Classification of finite reparametrization symmetry groups in the three-Higgs-doublet model
Ivanov, I P
2012-01-01
Symmetries play a crucial role in electroweak symmetry breaking models with non-minimal Higgs content. Within each class of these models, it is desirable to know which symmetry groups can be implemented via the scalar sector. In N-Higgs-doublet models, this classification problem was solved only for N=2 doublets. Very recently, we suggested a method to classify all realizable finite symmetry groups of Higgs-family transformations in the three-Higgs-doublet model (3HDM). Here, we present this classification in all detail together with an introduction to the theory of solvable groups, which play the key role in our derivation. We also consider generalized-CP symmetries, and discuss the interplay between Higgs-family symmetries and CP-conservation. In particular, we prove that presence of the $Z_4$ symmetry guarantees the explicit CP-conservation of the potential. This work completes classification of finite reparametrization symmetry groups in 3HDM.
Classification of finite reparametrization symmetry groups in the three-Higgs-doublet model
Ivanov, Igor P. [Universite de Liege, IFPA, Liege (Belgium); Sobolev Institute of Mathematics, Novosibirsk (Russian Federation); Vdovin, E. [Sobolev Institute of Mathematics, Novosibirsk (Russian Federation)
2013-02-15
Symmetries play a crucial role in electroweak symmetry breaking models with non-minimal Higgs content. Within each class of these models, it is desirable to know which symmetry groups can be implemented via the scalar sector. In N-Higgs-doublet models, this classification problem was solved only for N=2 doublets. Very recently, we suggested a method to classify all realizable finite symmetry groups of Higgs-family transformations in the three-Higgs-doublet model (3HDM). Here, we present this classification in all detail together with an introduction to the theory of solvable groups, which play the key role in our derivation. We also consider generalized-CP symmetries, and discuss the interplay between Higgs-family symmetries and CP-conservation. In particular, we prove that presence of the Z{sub 4} symmetry guarantees the explicit CP-conservation of the potential. This work completes classification of finite reparametrization symmetry groups in 3HDM. (orig.)
Classification of finite reparametrization symmetry groups in the three-Higgs-doublet model
Ivanov, Igor P.; Vdovin, E.
2013-02-01
Symmetries play a crucial role in electroweak symmetry breaking models with non-minimal Higgs content. Within each class of these models, it is desirable to know which symmetry groups can be implemented via the scalar sector. In N-Higgs-doublet models, this classification problem was solved only for N=2 doublets. Very recently, we suggested a method to classify all realizable finite symmetry groups of Higgs-family transformations in the three-Higgs-doublet model (3HDM). Here, we present this classification in all detail together with an introduction to the theory of solvable groups, which play the key role in our derivation. We also consider generalized- CP symmetries, and discuss the interplay between Higgs-family symmetries and CP-conservation. In particular, we prove that presence of the ℤ4 symmetry guarantees the explicit CP-conservation of the potential. This work completes classification of finite reparametrization symmetry groups in 3HDM.
Nilpotent Symmetries in Super-Group Field Cosmology
Upadhyay, Sudhaker
2015-01-01
In this paper we study the gauge invariance of the third quantized super-group field cosmology which is a model for multiverse. Further, we propose both the nfinitesimal (usual) as well as the finite superfield-dependent BRST symmetry transformations which leave the effective theory invariant. The effects of finite superfield-dependent BRST transformations on the path integral (so-called void functional in the case of third quantization) are implemented. Within the finite superfield-dependent BRST formulation, the finite superfield-dependent BRST transformations with specific parameter switch the void functional from one gauge to another. We establish this result for the most general gauge with the help of explicit calculations which holds for all possible sets of gauge choices at both the classical and the quantum levels.
Symmetry breaking, subgroup embeddings and the Weyl group
George, Damien P; Thompson, Jayne E; Volkas, Raymond R
2013-01-01
We present a systematic approach to writing adjoint Higgs vacuum expectation values (vevs), which break a symmetry G to differently embedded isomorphic copies of a subgroup belonging to the chain $G \\supset H_1 \\supset ... \\supset H_l $, as linear combinations of each other. Given an adjoint Higgs vacuum expectation value h breaking G \\rightarrow H, a full complement of vevs breaking G to different embeddings of the subgroup H can be generated through the Weyl group orbit of h. An explicit formula for recovering each vev is given. We focus on the case when H stabilizes the highest weight of the lowest dimensional fundamental representation, where the formula is exceedingly simple. We also discuss cases when the Higgs field is not in the adjoint representation and apply these techniques to current research problems, especially in domain-wall brane model building.
Symmetries, Information and Monster Groups before and after the Big Bang
Arturo Tozzi
2016-12-01
Full Text Available The Monster group, the biggest of the sporadic groups, is equipped with the highest known number of dimensions and symmetries. Taking into account variants of the Borsuk–Ulam theorem and a novel topological approach cast in a physical fashion that has the potential to be operationalized, the universe can be conceived as a lower-dimensional manifold encompassed in the Monster group. Our universe might arise from spontaneous dimension decrease and symmetry breaking that occur inside the very structure of the Monster Module. We elucidate how the energetic loss caused by projection from higher to lower dimensions and by the Monster group’s non-abelian features is correlated with the present-day asymmetry in the thermodynamic arrow. By linking the Monster Module to its theoretical physical counterparts, it is then possible to calculate its enthalpy and Lie group trajectories. Our approach also reveals how a symmetry break might lead to a universe based on multi-dimensional string theories and CFT/AdS (anti-de Sitter/conformal field theory correspondence.
Symmetry groups and spiral wave solution of a wave propagation equation
张全举; 屈长征
2002-01-01
We study a third-order nonlinear evolution equation, which can be transformed to the modified KdV equation,using the Lie symmetry method. The Lie point symmetries and the one-dimensional optimal system of the symmetryalgebras are determined. Those symmetries are some types of nonlocal symmetries or hidden symmetries of the modifiedKdV equation. The group-invariant solutions, particularly the travelling wave and spiral wave solutions, are discussedin detail, and a type of spiral wave solution which is smooth in the origin is obtained.
EXECUTIVE SUMMARY OF THE SNOWMASS 2001 WORKING GROUP : ELECTROWEAK SYMMETRY BREAKING.
CARENA,M.; GERDES,D.W.; HABER,H.E.; TURCOT,A.S.; ZERWAS,P.M.
2001-06-30
In this summary report of the 2001 Snowmass Electroweak Symmetry Breaking Working Group, the main candidates for theories of electroweak symmetry breaking are surveyed, and the criteria for distinguishing among the different approaches are discussed. The potential for observing electroweak symmetry breaking phenomena at the upgraded Tevatron and the LHC is described. We emphasize the importance of a high-luminosity e{sup +}e{sup -} linear collider for precision measurements to clarify the underlying electroweak symmetry breaking dynamics. Finally, we note the possible roles of the {mu}{sup +} {mu}{sup -} collider and VLHC for further elucidating the physics of electroweak symmetry breaking.
Dynamical symmetry breaking in chiral gauge theories with direct-product gauge groups
Shi, Yan-Liang; Shrock, Robert
2016-09-01
We analyze patterns of dynamical symmetry breaking in strongly coupled chiral gauge theories with direct-product gauge groups G . If the gauge coupling for a factor group Gi⊂G becomes sufficiently strong, it can produce bilinear fermion condensates that break the Gi symmetry itself and/or break other gauge symmetries Gj⊂G . Our comparative study of a number of strongly coupled direct-product chiral gauge theories elucidates how the patterns of symmetry breaking depend on the structure of G and on the relative sizes of the gauge couplings corresponding to factor groups in the direct product.
Dynamical Symmetry Breaking in Chiral Gauge Theories with Direct-Product Gauge Groups
Shi, Yan-Liang
2016-01-01
We analyze patterns of dynamical symmetry breaking in strongly coupled chiral gauge theories with direct-product gauge groups $G$. If the gauge coupling for a factor group $G_i \\subset G$ becomes sufficiently strong, it can produce bilinear fermion condensates that break the $G_i$ symmetry itself and/or break other gauge symmetries $G_j \\subset G$. Our comparative study of a number of strongly coupled direct-product chiral gauge theories elucidates how the patterns of symmetry breaking depend on the structure of $G$ and on the relative sizes of the gauge couplings corresponding to factor groups in the direct product.
Spontaneous R-symmetry breaking from the renormalization group flow
Amariti, Antonio
2012-01-01
We propose a mechanism of R-symmetry breaking in four-dimensional DSB models based on the RG properties of the coupling constants. By constraining the UV sector, we generate new hierarchies amongst the couplings that allow a spontaneously broken R-symmetry in models with pure chiral fields of R-charges R = 0 and R = 2 only. The result is obtained by a combination of one- and two-loop effects, both at the origin of field space and in the region dominated by leading log potentials.
Noncommutative Integration and Symmetry Algebra of the Dirac Equation on the Lie Groups
Breev, A. I.; Mosman, E. A.
2016-12-01
The algebra of first-order symmetry operators of the Dirac equation on four-dimensional Lie groups with right-invariant metric is investigated. It is shown that the algebra of symmetry operators is in general not a Lie algebra. Noncommutative reduction mediated by spin symmetry operators is investigated. For the Dirac equation on the Lie group SO(2,1) a parametric family of particular solutions obtained by the method of noncommutative integration over a subalgebra containing a spin symmetry operator is constructed.
Virtual and Printed 3D Models for Teaching Crystal Symmetry and Point Groups
Casas, Lluís; Estop, Euge`nia
2015-01-01
Both, virtual and printed 3D crystal models can help students and teachers deal with chemical education topics such as symmetry and point groups. In the present paper, two freely downloadable tools (interactive PDF files and a mobile app) are presented as examples of the application of 3D design to study point-symmetry. The use of 3D printing to…
Mirror symmetry and projective geometry of Reye congruences I
Hosono, Shinobu
2011-01-01
Studying the mirror symmetry of a Calabi-Yau threefold $X$ of the Reye congruence in $\\mP^4$, we conjecture that $X$ has a non-trivial Fourier-Mukai partner $Y$. We construct $Y$ as the double cover of a determinantal quintic in $\\mP^4$ branched over a curve. We also calculate BPS numbers of both $X$ and $Y$ (and also a related Calabi-Yau complete intersection $\\tilde X_0$) using mirror symmetry.
Symmetry and Condensed Matter Physics
El-Batanouny, M.; Wooten, F.
2008-03-01
Preface; 1. Symmetry and physics; 2. Symmetry and group theory; 3. Group representations: concepts; 4. Group representations: formalism and methodology; 5. Dixon's method for computing group characters; 6. Group action and symmetry projection operators; 7. Construction of the irreducible representations; 8. Product groups and product representations; 9. Induced representations; 10. Crystallographic symmetry and space-groups; 11. Space groups: Irreps; 12. Time-reversal symmetry: color groups and the Onsager relations; 13. Tensors and tensor fields; 14. Electronic properties of solids; 15. Dynamical properties of molecules, solids and surfaces; 16. Experimental measurements and selection rules; 17. Landau's theory of phase transitions; 18. Incommensurate systems and quasi-crystals; References; Bibliography; Index.
Fermat Surface and Group Theory in Symmetry of Rapidity Family in Chiral Potts Model
Roan, Shi-shyr
2013-01-01
The present paper discusses various mathematical aspects about the rapidity symmetry in chiral Potts model (CPM) in the context of algebraic geometry and group theory . We re-analyze the symmetry group of a rapidity curve in $N$-state CPM, explore the universal group structure for all $N$, and further enlarge it to modular symmetries of the complete rapidity family in CPM. As will be shown in the article that all rapidity curves in $N$-state CPM constitute a Fermat hypersurface in $\\PZ^3$ of degree 2N as the natural generalization of the Fermat K3 elliptic surface $(N=2)$, we conduct a thorough algebraic geometry study about the rapidity fibration of Fermat surface and its reduced hyperelliptic fibration via techniques in algebraic surface theory. Symmetries of rapidity family in CPM and hyperelliptic family in $\\tau^{(2)}$-model are exhibited through the geometrical representation of the universal structural group in mathematics.
Symmetries in a very special relativity and isometric group of Finsler space
LI Xin; CHANG Zhe; MO Xiao-Huan
2011-01-01
We present an explicit connection between the symmetries in a Very Special Relativity (VSR) and isometric group of a specific Finsler space. It is shown that the line element that is invariant under the VSR symmetric group is a Finslerian one. The Killing vectors in Finsler space are constructed in a systematic way. The Lie algebras corresponding to the symmetries of VSR are obtained from a geometric famework. The dispersion relation and the Lorentz invariance violation effect in the VSR are discussed.
Symmetries of preon interactions modeled as a finite group
Bellinger, James N.
1997-07-01
I model preon interactions as a finite group. Treating the elements of the group as the bases of a vector space, I examine those linear mappings under which the transformed bases may be treated as members of a group isomorphic to the original. In some cases these mappings are continuous Lie groups.
Symmetries of preon interactions modeled as a finite group
Bellinger, J.N. [University of Wisconsin at Madison, Madison, Wisconsin 53706 (United States)
1997-07-01
I model preon interactions as a finite group. Treating the elements of the group as the bases of a vector space, I examine those linear mappings under which the transformed bases may be treated as members of a group isomorphic to the original. In some cases these mappings are continuous Lie groups. {copyright} {ital 1997 American Institute of Physics.}
Building projected entangled pair states with a local gauge symmetry
Zohar, Erez; Burrello, Michele
2016-04-01
Tensor network states, and in particular projected entangled pair states (PEPS), suggest an innovative approach for the study of lattice gauge theories, both from a pure theoretic point of view, and as a tool for the analysis of the recent proposals for quantum simulations of lattice gauge theories. In this paper we present a framework for describing locally gauge invariant states on lattices using PEPS. The PEPS constructed hereby shall include both bosonic and fermionic states, suitable for all combinations of matter and gauge fields in lattice gauge theories defined by either finite or compact Lie groups.
Building Projected Entangled Pair States with a Local Gauge Symmetry
Zohar, Erez
2015-01-01
Tensor network states, and in particular projected entangled pair states (PEPS), suggest an innovative approach for the study of lattice gauge theories, both from a pure theoretic point of view, and as a tool for the analysis of the recent proposals for quantum simulations of lattice gauge theories. In this paper we present a framework for describing locally gauge invariant states on lattices using PEPS. The PEPS constructed hereby shall include both bosonic and fermionic states, suitable for all combinations of matter and gauge fields in lattice gauge theories defined by either finite or compact Lie groups.
Wahlen-Strothman, Jacob M; Hermes, Matthew R; Degroote, Matthias; Qiu, Yiheng; Zhao, Jinmo; Dukelsky, Jorge; Scuseria, Gustavo E
2016-01-01
Coupled cluster and symmetry projected Hartree-Fock are two central paradigms in electronic structure theory. However, they are very different. Single reference coupled cluster is highly successful for treating weakly correlated systems, but fails under strong correlation unless one sacrifices good quantum numbers and works with broken-symmetry wave functions, which is unphysical for finite systems. Symmetry projection is effective for the treatment of strong correlation at the mean-field level through multireference non-orthogonal configuration interaction wavefunctions, but unlike coupled cluster, it is neither size extensive nor ideal for treating dynamic correlation. We here examine different scenarios for merging these two dissimilar theories. We carry out this exercise over the integrable Lipkin model Hamiltonian, which despite its simplicity, encompasses non-trivial physics for degenerate systems and can be solved via diagonalization for a very large number of particles. We show how symmetry projection...
Symmetries and groups in particle physics; Symmetrien und Gruppen in der Teilchenphysik
Scherer, Stefan [Mainz Univ. (Germany)
2016-07-01
The aim of this book consists of a didactic introduction to the group-theoretical considerations and methods, which have led to an ever deeper understanding of the interactions of the elementary particles. The first three chapters deal primarily with the foundations of the representation theory of primarily finite groups, whereby many results are also transferable to compact Lie groups. In the third chapter we discuss the concept of Lie groups and their connection with Lie algebras. In the remaining chapter it is mainly about the application of group theory in physics. Chapter 4 deals with the groups SO(3) and SU(2), which occur in connection with the description of the angular momentum in quantum mechanics. We discuss the Wigner-Eckar theorem together with some applications. In chapter 5 we are employed to the composition properties of strongly interacting systems, so called hadrons, and discuss extensively the transformation properties of quarks with relation to the special unitary groups. The Noether theorem is generally treated in connection to the conservation laws belonging to the Galilei group and the Poincare group. We confine us in chapter 6 to internal symmetries, but explain for that extensively the application to quantum field theory. Especially an outlook on the effect of symmetries in form of so called Ward identities is granted. In chapter 7 we turn towards the gauge principle and discuss first the construction of quantum electrodynamics. In the following we generalize the gauge principle to non-Abelian groups (Yang-Mills theories) and formulate the quantum chromodynamics (QCD). Especially we take a view of ''random'' global symmetries of QCD, especially the chiral symmetry. In chapter 8 we illuminate the phenomenon of spontaneous symmetry breaking both for global and for local symmetries. In the final chapter we work out the group-theoretical structure of the Standard Model. Finally by means of the group SU(5) we take a view to
Symmetry group and group representations associated with the thermodynamic covariance principle
Sonnino, Giorgio; Evslin, Jarah; Sonnino, Alberto; Steinbrecher, György; Tirapegui, Enrique
2016-10-01
The main objective of this work [previously appeared in literature, the thermodynamical field theory (TFT)] is to determine the nonlinear closure equations (i.e., the flux-force relations) valid for thermodynamic systems out of Onsager's region. The TFT rests upon the concept of equivalence between thermodynamic systems. More precisely, the equivalent character of two alternative descriptions of a thermodynamic system is ensured if, and only if, the two sets of thermodynamic forces are linked with each other by the so-called thermodynamic coordinate transformations (TCT). In this work, we describe the Lie group and the group representations associated to the TCT. The TCT guarantee the validity of the so-called thermodynamic covariance principle (TCP): The nonlinear closure equations, i.e., the flux-force relations, everywhere and in particular outside the Onsager region, must be covariant under TCT. In other terms, the fundamental laws of thermodynamics should be manifestly covariant under transformations between the admissible thermodynamic forces, i.e., under TCT. The TCP ensures the validity of the fundamental theorems for systems far from equilibrium. The symmetry properties of a physical system are intimately related to the conservation laws characterizing that system. Noether's theorem gives a precise description of this relation. We derive the conserved (thermodynamic) currents and, as an example of calculation, a system out of equilibrium (tokamak plasmas) where the validity of TCP imposed at the level of the kinetic equations is also analyzed.
Symmetry group and group representations associated with the thermodynamic covariance principle.
Sonnino, Giorgio; Evslin, Jarah; Sonnino, Alberto; Steinbrecher, György; Tirapegui, Enrique
2016-10-01
The main objective of this work [previously appeared in literature, the thermodynamical field theory (TFT)] is to determine the nonlinear closure equations (i.e., the flux-force relations) valid for thermodynamic systems out of Onsager's region. The TFT rests upon the concept of equivalence between thermodynamic systems. More precisely, the equivalent character of two alternative descriptions of a thermodynamic system is ensured if, and only if, the two sets of thermodynamic forces are linked with each other by the so-called thermodynamic coordinate transformations (TCT). In this work, we describe the Lie group and the group representations associated to the TCT. The TCT guarantee the validity of the so-called thermodynamic covariance principle (TCP): The nonlinear closure equations, i.e., the flux-force relations, everywhere and in particular outside the Onsager region, must be covariant under TCT. In other terms, the fundamental laws of thermodynamics should be manifestly covariant under transformations between the admissible thermodynamic forces, i.e., under TCT. The TCP ensures the validity of the fundamental theorems for systems far from equilibrium. The symmetry properties of a physical system are intimately related to the conservation laws characterizing that system. Noether's theorem gives a precise description of this relation. We derive the conserved (thermodynamic) currents and, as an example of calculation, a system out of equilibrium (tokamak plasmas) where the validity of TCP imposed at the level of the kinetic equations is also analyzed.
Eye and Iris Detection Using Projection and Radial Symmetry Transform
XIANG Shu-lan; CAO Cheng; Aishy Amer
2010-01-01
This paper presents an eye and iris detection algorithm for human facial images. The authors combine three features of the eye to develop the algorithm: 1) the pixels surrounding the eyes are more variable than other parts of the face; 2) eye pixels are darker than their neighbors; 3) eyes often exhibit radial symmetric properties. Through the first feature, two rough regions of both eyes are detected on the face. Eye masks are then formed based on the second feature, and a fast radial symmetry transform is applied to the two rough regions of both eyes. Finally, accurate iris centers are located by searching the maximum value of the radial symmetry transform results. Using 450 human facial images from the Caltech face database, experiments show that the success rate of the proposed method is 91.7%. The effectiveness of the method was also verified through detection of video frames.
On the Physical Reasons for the Extension of Symmetry Groups in Molecular Spectroscopy
Carlo di Lauro
2010-02-01
Full Text Available Several situations of general interest, in which the symmetry groups usually applied to spectroscopy problems need to be extended, are reviewed. It is emphasized that any symmetry group of geometrical operations to be used in Molecular Spectroscopy should be extended for completeness by considering the time reversal operator, as far as the Hamiltonian is invariant with respect to the inversion of the direction of motion. This can explain the degeneracy of pairs of vibrational and rotational states spanning the so-called separably degenerate irreducible representations, in symmetric tops of low symmetry, and Kramers degeneracy in odd electron molecules in the absence of magnetic fields. An extension with account of time reversal is also useful to determine relative phase conventions on vibration-rotation wavefunctions, which render all vibration-rotation matrix elements real. An extension of a molecular symmetry group may be required for molecules which can attain different geometries by large amplitude periodical motions, if such motions are hindered and are not completely free. Special cases involving the internal rotation are discussed in detail. It is observed that the symmetry classification of vibrational modes involving displacements normal to the internal rotation axis is not univocal, but can be done in several ways, which actually correspond to different conventions on the separation of vibration and internal rotation in the adopted basis functions. The symmetry species of the separate vibrational and torsional factors of these functions depend on the adopted convention.
Projected Entangled Pair States with non-Abelian gauge symmetries: an SU(2) study
Zohar, Erez; Burrello, Michele; Cirac, J Ignacio
2016-01-01
Over the last years, Projected Entangled Pair States have demonstrated great power for the study of many body systems, as they naturally describe ground states of gapped many body Hamiltonians, and suggest a constructive way to encode and classify their symmetries. The PEPS study is not only limited to global symmetries, but has also been extended and applied for local symmetries, allowing to use them for the description of states in lattice gauge theories. In this paper we discuss PEPS with a local, SU(2) gauge symmetry, and demonstrate the use of PEPS features and techniques for the study of a simple family of many body states with a non-Abelian gauge symmetry. We present, in particular, the construction of fermionic PEPS able to describe both two-color fermionic matter and the degrees of freedom of an SU(2) gauge field with a suitable truncation.
Projected Entangled Pair States with non-Abelian gauge symmetries: An SU(2) study
Zohar, Erez; Wahl, Thorsten B.; Burrello, Michele; Cirac, J. Ignacio
2016-11-01
Over the last years, Projected Entangled Pair States have demonstrated great power for the study of many body systems, as they naturally describe ground states of gapped many body Hamiltonians, and suggest a constructive way to encode and classify their symmetries. The PEPS study is not only limited to global symmetries, but has also been extended and applied for local symmetries, allowing to use them for the description of states in lattice gauge theories. In this paper we discuss PEPS with a local, SU(2) gauge symmetry, and demonstrate the use of PEPS features and techniques for the study of a simple family of many body states with a non-Abelian gauge symmetry. We present, in particular, the construction of fermionic PEPS able to describe both two-color fermionic matter and the degrees of freedom of an SU(2) gauge field with a suitable truncation.
Morse Theory for Flows in Presence of a Symmetry Group.
1984-07-01
n. 2534. [15] J. J. Rotman , An Introduction to Homological Algebra , Academic Press, New York (1979). (16] S. H. Spanier, Algebraic Topology, McGraw... algebra , a method of treating finite groups is described. I ~-- *. --- ptA The responsibility for the wording and views expressed in this descriptive...Aut A. The definition of a G-module A, essentially means that there is an action of G on A which also considers the algebraic structure of A. In
Quantum groups as generalized gauge symmetries in WZNW models. Part I. The classical model
Hadjiivanov, L.; Furlan, P.
2017-07-01
Wess-Zumino-Novikov-Witten (WZNW) models over compact Lie groups G constitute the best studied class of (two dimensional, 2 D) rational conformal field theories (RCFTs). A WZNW chiral state space is a finite direct sum of integrable representations of the corresponding affine (current) algebra, and the correlation functions of primary fields are monodromy invariant combinations of left times right sector conformal blocks solving the Knizhnik-Zamolodchikov equation. However, even in this very well understood case of 2 D RCFT, the "internal" (gauge) symmetry that governs the ensuing fusion rules remains unclear. On the other hand, the canonical approach to the classical chiral WZNW theory developed by Faddeev, Alekseev, Shatashvili, Gawedzki and Falceto reveals its Poisson-Lie symmetry. After a covariant quantization, the latter gives rise to an associated quantum group symmetry which naturally requires an extension of the state space. This paper contains a review of earlier work on the subject with a special emphasis, in the case G = SU( n), on the emerging chiral "WZNW zero modes" which provide an adequate algebraic description of the internal symmetry structure of the model. Combining further left and right zero modes, one obtains a specific dynamical quantum group, the structure of its Fock representation resembling the axiomatic approach to gauge theories in which a "restricted" quantum group plays the role of a generalized gauge symmetry.
Orbifold groups, quasi-projectivity and covers
Bartolo, Enrique Artal; Matei, Daniel
2012-01-01
We discuss properties of complex algebraic orbifold groups, their characteristic varieties, and their abelian covers. In particular, we deal with the question of (quasi)-projectivity of orbifold groups. We also prove a structure theorem for the variety of characters of normal-crossing quasi-projective orbifold groups. Finally, we extend Sakuma's formula for the first Betti number of abelian covers of orbifold fundamental groups. Several examples are presented, including a compact orbifold group which is not projective and a Zariski pair of plane projective curves that can be told by considering an unbranched cover of the projective plane with an orbifold structure.
Symmetry group prerequisite for E-infinity in high energy physics
El Naschie, M.S. [Department of Physics, Alexandria University (United Kingdom); KACST, Riyadh (Saudi Arabia); Department of Astrophysics, Cairo University, Cairo (Egypt)], E-mail: Chaossf@aol.com
2008-01-15
The work addresses the question of extending certain symplectic and exceptional Lie Symmetry groups to the realm of chaotic dynamics. Using a collection of simple examples, the technique of transfinite continuation is illustrated and various physically relevant results are obtained. The paper is intended as an elementary introduction to the use of symmetry groups in transfinite physics and as such is a sequel to a series of previous papers constituting the elementary and advanced mathematical prerequisite for a proper understanding of E-infinity theory.
Painleve analysis and symmetry group for the coupled Zakharov-Kuznetsov equation
Hu, Heng-Chun, E-mail: hhengchun@163.com [College of Science, University of Shanghai for Science and Technology, Shanghai 200093 (China); Jia, Xiao-Qing; Sang, Ben-Wen [College of Science, University of Shanghai for Science and Technology, Shanghai 200093 (China)
2011-09-12
The Painleve property for the coupled Zakharov-Kuznetsov equation is verified with the WTC approach and new exact solutions of bell-type are constructed from standard truncated expansion. A symmetry transformation group theorem is also given out from a simple direct method. -- Highlights: → Painleve property for coupled Zakharov-Kuznetsov system is verified by WTC method. → Symmetry group for coupled ZK system is given out by a simple direct method. → Bell-type solution for coupled ZK system is constructed from standard truncation.
Similar Symmetries: The Role of Wallpaper Groups in Perceptual Texture Similarity
Fraser Halley
2011-05-01
Full Text Available Periodic patterns and symmetries are striking visual properties that have been used decoratively around the world throughout human history. Periodic patterns can be mathematically classified into one of 17 different Wallpaper groups, and while computational models have been developed which can extract an image's symmetry group, very little work has been done on how humans perceive these patterns. This study presents the results from a grouping experiment using stimuli from the different wallpaper groups. We find that while different images from the same wallpaper group are perceived as similar to one another, not all groups have the same degree of self-similarity. The similarity relationships between wallpaper groups appear to be dominated by rotations.
Light Cone $W_n$ Geometry and its Symmetries and Projective Field Theory
Zucchini, R
1993-01-01
I show that the generalized Beltrami differentials and projective connections which appear naturally in induced light cone $W_n$ gravity are geometrical fields parametrizing in one-to-one fashion generalized projective structures on a fixed base Riemann surface. I also show that $W_n$ symmetries are nothing but gauge transformations of the flat ${SL}(n,{\\bf C})$ vector bundles canonically associated to the generalized projective structures. This provides an original formulation of classical light cone $W_n$ geometry. From the knowledge of the symmetries, the full BRS algebra is derived. Inspired by the results of recent literature, I argue that quantum $W_n$ gravity may be formulated as an induced gauge theory of generalized projective connections. This leads to projective field theory. The possible anomalies arising at the quantum level are analyzed by solving Wess-Zumino consistency conditions. The implications for induced covariant $W_n$ gravity are briefly discussed. The results presented, valid for arbit...
More on PT-Symmetry in (Generalized Effect Algebras and Partial Groups
J. Paseka
2011-01-01
Full Text Available We continue in the direction of our paper on PT-Symmetry in (Generalized Effect Algebras and Partial Groups. Namely we extend our considerations to the setting of weakly ordered partial groups. In this setting, any operator weakly ordered partial group is a pasting of its partially ordered commutative subgroups of linear operators with a fixed dense domain over bounded operators. Moreover, applications of our approach for generalized effect algebras are mentioned.
de Klerk, E.; Sotirov, R.
2007-01-01
We consider semidefinite programming relaxations of the quadratic assignment problem, and show how to exploit group symmetry in the problem data. Thus we are able to compute the best known lower bounds for several instances of quadratic assignment problems from the problem library: [R.E. Burkard,
Structure of Symmetry Groups via Cartan's Method: Survey of Four Approaches
Oleg I. Morozov
2005-10-01
Full Text Available In this review article we discuss four recent methods for computing Maurer-Cartan structure equations of symmetry groups of differential equations. Examples include solution of the contact equivalence problem for linear hyperbolic equations and finding a contact transformation between the generalized Hunter-Saxton equation and the Euler-Poisson equation.
de Klerk, E.; Sotirov, R.
2007-01-01
We consider semidefinite programming relaxations of the quadratic assignment problem, and show how to exploit group symmetry in the problem data. Thus we are able to compute the best known lower bounds for several instances of quadratic assignment problems from the problem library: [R.E. Burkard, S.
Alexis De Vos
2011-06-01
Full Text Available Whereas quantum computing circuits follow the symmetries of the unitary Lie group, classical reversible computation circuits follow the symmetries of a finite group, i.e., the symmetric group. We confront the decomposition of an arbitrary classical reversible circuit with w bits and the decomposition of an arbitrary quantum circuit with w qubits. Both decompositions use the control gate as building block, i.e., a circuit transforming only one (qubit, the transformation being controlled by the other w−1 (qubits. We explain why the former circuit can be decomposed into 2w − 1 control gates, whereas the latter circuit needs 2w − 1 control gates. We investigate whether computer circuits, not based on the full unitary group but instead on a subgroup of the unitary group, may be decomposable either into 2w − 1 or into 2w − 1 control gates.
Aoki, Ken-Ichi; Sato, Daisuke
2016-01-01
We analyze the dynamical chiral symmetry breaking in gauge theory with the nonperturbative renormalization group equation (NPRGE), which is a first order nonlinear partial differential equation (PDE). In case that the spontaneous chiral symmetry breaking occurs, the NPRGE encounters some non-analytic singularities at the finite critical scale even though the initial function is continuous and smooth. Therefore there is no usual solution of the PDE beyond the critical scale. In this paper, we newly introduce the notion of a weak solution which is the global solution of the weak NPRGE. We show how to evaluate the physical quantities with the weak solution.
Non-Lie Symmetry Group and New Exact Solutions for the Two-Dimensional KdV-Burgers Equation
WANG Hong; TIAN Ying-Hui; CHEN Han-Lin
2011-01-01
@@ By using the modified Clarkson-Kruskal (CK) direct method, we obtain the non-Lie symmetry group of the two-dimensional KdV-Burgers equation.Under some constraint conditions, Lie point symmetry is also obtained.Through the symmetry group, some new exact solutions of the two-dimensional KdV-Burgers equation are found.%By using the modified Clarkson-Kruskal (CK) direct method, we obtain the non-Lie symmetry group of the two-dimensional KdV-Burgers equation. Under some constraint conditions, Lie point symmetry is also obtained.Through the symmetry group, some new exact solutions of the two-dimensional KdV-Burgers equation are found.
Full Symmetry Groups and Exact Solutions to BKP and GKP Equations
Bo Ren
2014-01-01
Full Text Available We investigate the (2+1-dimensional nonlinear BKP and GKP equations with the modified direct CK’s method. Then, we get its Lie point groups and the full symmetry group, and a relationship is constructed between the new solutions and the old one. Based on the relationship, the new solutions can be obtained by using a given solution of the equations.
Ibragimov, Nail H; Kovalev, Vladimir F
2011-01-01
74J30The maximal group of Lie point symmetries of a system of nonlinear equations used in geophysical fluid dynamics is presented. The Lie algebra of this group is infinite-dimensional and involves three arbitrary functions of time. The invariant solution under the rotation and dilation is constructed. Qualitative analysis of the invariant solution is provided and the energy of this solution is presented.
Fulbright-Hays Group Projects Abroad Program
Office of Postsecondary Education, US Department of Education, 2012
2012-01-01
The Fulbright-Hays Group Projects Abroad program provides grants to support overseas projects in training, research, and curriculum development in modern foreign languages and area studies by teachers, undergraduate and graduate students, and faculty engaged in a common endeavor. Projects may include short-term seminars, curriculum development,…
Higashikawa, Sho
2016-01-01
A symmetry broken phase of a system with internal degrees of freedom often features a complex order parameter, which generates a rich variety of topological excitations and topological influence between them, yet the very complexity of the order parameter makes it difficult to treat topological excitations and topological influence in a unified manner. To overcome this problem, we develop a general method to calculate homotopy groups and derive decomposition formulas which express homotopy groups of a quotient space $G/H$ in terms of those of the symmetry $G$ of the system and those of the remaining symmetry $H$ of the state. We apply these formulas to analyze a general monopole and a general three-dimensional skyrmion, and show that their textures are obtained through substitution of the corresponding $\\mathfrak{su}(2)$-subalgebra for the $\\mathfrak{su}(2)$-spin. We also show that a discrete symmetry of $H$ is necessary for the presence of topological influence and find the topological influence on a skyrmio...
Correlation functions in isotropic and anisotropic turbulence the role of the symmetry group
Arad, I; Procaccia, I; Arad, Itai; L'vov, Victor S.; Procaccia, Itamar
1998-01-01
The theory of fully developed turbulence is usually considered in an idealized homogeneous and isotropic state. Real turbulent flows exhibit the effects of anisotropic forcing. The analysis of correlation functions and structure functions in isotropic and anisotropic situations is facilitated and made rational when performed in terms of the irreducible representations of the relevant symmetry group which is the group of all rotations SO(3). In this paper we firstly consider the needed general theory and explain why we expect different (universal) scaling exponents in the different sectors of the symmetry group. We exemplify the theory context of isotropic turbulence (for third order tensorial structure functions) and in weakly anisotropic turbulence (for the second order structure function). The utility of the resulting expressions for the analysis of experimental data is demonstrated in the context of high Reynolds number measurements of turbulence in the atmosphere.
Symmetry breaking in fluid dynamics: Lie group reducible motions for real fluids
Holm, D.D.
1976-07-01
The physics of fluids is based on certain kinematical invariance principles, which refer to coordinate systems, dimensions, and Galilean reference frames. Other, thermodynamic, symmetry principles are introduced by the material description. In the present work, the interplay between these two kinds of invariance principles is used to solve for classes of one-dimensional non-steady isentropic motions of a fluid whose equation of state is of Mie-Gruneisen type. Also, the change in profile and attenuation of weak shock waves in a dissipative medium is studied at the level of Burgers' approximation from the viewpoint of its underlying symmetry structure. The mathematical method of approach is based on the theory of infinitesimal Lie groups. Fluid motions are characterized according to inequivalent subgroups of the full invariance group of the flow description and exact group reducible solutions are presented.
[Re]constructing Finite Flavour Groups: Horizontal Symmetry Scans from the Bottom-Up
Talbert, Jim
2014-01-01
We present a novel procedure for identifying discrete, leptonic flavour symmetries, given a class of unitary mixing matrices. By creating explicit 3D representations for generators of residual symmetries in both the charged lepton and neutrino sector, we reconstruct large(r) non-abelian flavour groups using the GAP language for computational finite algebra. We use experimental data to construct only those generators that yield acceptable (or preferable) mixing patterns. Such an approach is advantageous because it 1) can reproduce known groups from other 'top-down' scans while elucidating their origins from residuals, 2) find new previously unconsidered groups, and 3) serve as a powerful model building tool for theorists wishing to explore exotic flavour scenarios. We test our procedure on a generalization of the canonical tri-bimaximal (TBM) form.
Lifts of projective congruence groups, II
Kiming, Ian
2014-01-01
We continue and complete our previous paper ``Lifts of projective congruence groups'' concerning the question of whether there exist noncongruence subgroups of that are projectively equivalent to one of the groups or . A complete answer to this question is obtained: In case of such noncongruence...
Quantum groups as generalized gauge symmetries in WZNW models. Part II. The quantized model
Hadjiivanov, L.; Furlan, P.
2017-07-01
This is the second part of a paper dealing with the "internal" (gauge) symmetry of the Wess-Zumino-Novikov-Witten (WZNW) model on a compact Lie group G. It contains a systematic exposition, for G = SU( n), of the canonical quantization based on the study of the classical model (performed in the first part) following the quantum group symmetric approach first advocated by L.D. Faddeev and collaborators. The internal symmetry of the quantized model is carried by the chiral WZNW zero modes satisfying quadratic exchange relations and an n-linear determinant condition. For generic values of the deformation parameter the Fock representation of the zero modes' algebra gives rise to a model space of U q ( sl( n)). The relevant root of unity case is studied in detail for n = 2 when a "restricted" (finite dimensional) quotient quantum group is shown to appear in a natural way. The module structure of the zero modes' Fock space provides a specific duality with the solutions of the Knizhnik-Zamolodchikov equation for the four point functions of primary fields suggesting the existence of an extended state space of logarithmic CFT type. Combining left and right zero modes (i.e., returning to the 2 D model), the rational CFT structure shows up in a setting reminiscent to covariant quantization of gauge theories in which the restricted quantum group plays the role of a generalized gauge symmetry.
S-Matrices and Quantum Group Symmetry of q-Deformed Sigma Models
Hollowood, Timothy J; Schmidtt, David M
2015-01-01
Recently, several kinds of integrable deformations of the string world sheet theory in the gauge/gravity correspondence have been constructed. One class of these, the q-deformations with q a root of unity, has been shown to be related to a particular discrete deformation of the principal chiral models and (semi-)symmetric space sigma models involving a gauged WZW model. We conjecture a form for the exact S-matrices of the bosonic integrable field theories of this type. The S-matrices imply that the theories have a hidden infinite dimensional affine quantum group symmetry. We provide some evidence, via quantum inverse scattering techniques, that the theories do indeed possess the finite-dimensional part of this quantum group symmetry.
S-matrices and quantum group symmetry of k-deformed sigma models
Hollowood, Timothy J.; Miramontes, J. Luis; Schmidtt, David M.
2016-11-01
Recently, two kinds of integrable deformations of the string world sheet theory in the gauge/gravity correspondence have been constructed (Delduc et al 2014 Phys. Rev. Lett. 112 051601; Hollowood et al 2014 J. Phys. A: Math. Theor. 47 495402). One class of these, the k deformations associated to the more general q deformations but with q={{{e}}}{{i}π /k} a root of unity, has been shown to be related to a particular discrete deformation of the principal chiral models and (semi-)symmetric space sigma models involving a gauged WZW model. We conjecture a form for the exact S-matrices of the bosonic integrable field theories of this type. The S-matrices imply that the theories have a hidden infinite dimensional affine quantum group symmetry. We provide some evidence, via quantum inverse scattering techniques, that the theories do indeed possess the finite-dimensional part of this quantum group symmetry.
CP Symmetry and Lepton Mixing from a Scan of Finite Discrete Groups
Yao, Chang-Yuan
2016-01-01
Including the generalized CP symmetry, we have performed a comprehensive scan of leptonic mixing patterns which can be obtained from finite discrete groups with order less than 2000. Both the semidirect approach and its variant are considered. The lepton mixing matrices which can admit a good agreement with experimental data can be organized into eight different categories up to possible row and column permutations. These viable mixing patterns can be completely obtained from the discrete flavor groups $\\Delta(6n^2)$, $D^{(1)}_{9n,3n}$, $A_5$ and $\\Sigma(168)$ combined with CP symmetry. We perform a detailed analytical and numerical analysis for each possible mixing pattern. The resulting predictions for lepton mixing parameter, neutrinoless double decay and flavored leptogenesis are studied.
The Structure of Reduced Sudoku Grids and the Sudoku Symmetry Group
Siân K. Jones
2012-01-01
Full Text Available A Sudoku grid is a constrained Latin square. In this paper a reduced Sudoku grid is described, the properties of which differ, through necessity, from that of a reduced Latin square. The Sudoku symmetry group is presented and applied to determine a mathematical relationship between the number of reduced Sudoku grids and the total number of Sudoku grids for any size. This relationship simplifies the enumeration of Sudoku grids and an example of the use of this method is given.
Portfolio Assessment of an Undergraduate Group Project
Kuisma, Raija
2007-01-01
Students in the Physiotherapy Programme carried out a group project in their final year of studies. The objectives of the project were that the students learn and appreciate the process and activities involved in research, acquire deeper understanding of a topic in their professional interest, learn to work as a team, manage their own time,…
Regularities with random interactions in energy centroids defined by group symmetries
Kota, V K B
2005-01-01
Regular structures generated by random interactions in energy centroids defined over irreducible representations (irreps) of some of the group symmetries of the interacting boson models $sd$IBM, $sdg$IBM, $sd$IBM-$T$ and $sd$IBM-$ST$ are studied by deriving trace propagations equations for the centroids. It is found that, with random interactions, the lowest and highest group irreps in general carry most of the probability for the corresponding centroids to be lowest in energy. This generalizes the result known earlier, via numerical diagonalization, for the more complicated fixed spin ($J$) centroids where simple trace propagation is not possible.
Projective Normality of Weyl Group Quotients
S S Kannan; S K Pattanayak
2011-02-01
In this note, we prove that for the standard representation of the Weyl group of a semi-simple algebraic group of type $A_n,B_n,C_n,D_n,F_4$ and $G_2$ over $\\mathbb{C}$, the projective variety $\\mathbb{P}(V^m)/W$ is projectively normal with respect to the descent of $\\mathcal{O}(1)^{\\otimes|W|}$, where $V^m$ denote the direct sum of copies of .
Renormalization-group symmetries for solutions of nonlinear boundary value problems
Kovalev, V F
2008-01-01
Approximately 10 years ago, the method of renormalization-group symmetries entered the field of boundary value problems of classical mathematical physics, stemming from the concepts of functional self-similarity and of the Bogoliubov renormalization group treated as a Lie group of continuous transformations. Overwhelmingly dominating practical quantum field theory calculations, the renormalization-group method formed the basis for the discovery of the asymptotic freedom of strong nuclear interactions and underlies the Grand Unification scenario. This paper describes the logical framework of a new algorithm based on the modern theory of transformation groups and presents the most interesting results of application of the method to differential and/or integral equation problems and to problems that involve linear functionals of solutions. Examples from nonlinear optics, kinetic theory, and plasma dynamics are given, where new analytical solutions obtained with this algorithm have allowed describing the singular...
Molecular symmetry and group theory a programmed introduction to chemical applications
Vincent, Alan
2013-01-01
This substantially revised and expanded new edition of the bestselling textbook, addresses the difficulties that can arise with the mathematics that underpins the study of symmetry, and acknowledges that group theory can be a complex concept for students to grasp.Written in a clear, concise manner, the author introduces a series of programmes that help students learn at their own pace and enable to them understand the subject fully. Readers are taken through a series of carefully constructed exercises, designed to simplify the mathematics and give them a full understanding of how this
Michelot, F.
2004-04-01
We underline some inconsistencies in the work [J. Mol. Spectrosc. 219 (2003) 313] concerning symmetry adaptation in cubic groups. Also we show that some rather complicated methods presented can be easily avoided.
Symmetries and Laplacians introduction to harmonic analysis, group representations and applications
Gurarie, D
1992-01-01
Designed as an introduction to harmonic analysis and group representations,this book covers a wide range of topics rather than delving deeply into anyparticular one. In the words of H. Weyl ...it is primarily meant forthe humble, who want to learn as new the things set forth therein, rather thanfor the proud and learned who are already familiar with the subject and merelylook for quick and exact information.... The main objective is tointroduce the reader to concepts, ideas, results and techniques that evolvearound symmetry-groups, representations and Laplacians. Morespecifically, the main interest concerns geometrical objects and structures{X}, discrete or continuous, that possess sufficiently large symmetrygroup G, such as regular graphs (Platonic solids), lattices, andsymmetric Riemannian manifolds. All such objects have a natural Laplacian&Dgr;, a linear operator on functions over X, invariant underthe group action. There are many problems associated with Laplacians onX, such as continuous or discrete...
Symmetry Groups and Exact Solutions of New (4+1)-Dimensional Fokas Equation
YANG Zheng-Zheng; YAN Zhen-Ya
2009-01-01
In this paper, we investigate symmetries of the new (4+1)-dimensional Fokas equation, including point symmetries and the potential symmetries. We firstly employ the algorithmic procedure of computing the point symme-tries. And then we transform the Fokas equation into a potential system and gain the potential symmetries of Fokas equation. Finally, we use the obtained point symmetries and some constructive methods to get some doubly periodic wave solutions and other solutions of the Fokas equation. In particular, some solitary wave solutions are also given.
Gender and legitimacy in student project groups
Christensen, Gerd
Through empirical studies of project groups at university level, I have identified that there are a number of different forms of inclusion and exclusion processes in activity among the students. First, there are the processes that relate to the other students' skills. Here I found that the students....... The students who for some reason were categorized as stupid, lazy, dominant or antisocial had serious difficulties in finding a group to cooperate and write their project report with. In the worst case, this could mean that they had problems to complete their education. Even more surprising was the fact that I...
Cycle symmetry and its causes, Cisco Group (Virgilian and Wolfcampian), Texas
Yang, W. [Univ. of Texas, Austin, TX (United States). Dept. of Geological Sciences
1996-11-01
181 transgressive-regressive cycles composed of nonmarine and marine carbonate and siliciclastic rocks of the Cisco Group on the Eastern Shelf, Texas, display complex characteristics at both hemicycle and full-cycle scales. They are delineated on the basis of successive changes of depositional environments, stratal boundary relations, and stratigraphic position. Transgressive and regressive stratigraphic environment gradients are defined as the magnitude of environmental shift divided by thickness for each hemicycle. They indicate the rates of lateral environmental shifts during transgression and regression. Cycle symmetry index is defined as the ratio between transgressive and regressive stratigraphic environment gradients. It provides a measure of stratigraphic response to controlling processes. Five Cisco cycle types defined by the type of component lithofacies display the stratigraphic response mainly to noncyclic allogenic and autogenic processes. The cycle types have varying magnitude, thickness, and symmetry. They also vary in lateral extent and in abundance. A process-response model of cyclic sedimentation of the Cisco Group on the Eastern Shelf is established. It emphasizes the interplay between autogenic and allogenic processes at the sub-cycle scale. Understanding interactions among glacio-eustasy, climate, shelf subsidence, sediment supply, and depositional dynamics during various stages of transgression and regression is central to a clearer comprehension of the observed variations in cycle characteristics.
Group Organized Project Work in Distance Education
Helbo, Jan; Knudsen, Morten; Jensen, Lars Peter
2001-01-01
Project organized problem based learning is a successful concept for on-campus education at Aalborg University. Recently this "Aalborg concept" has been used in networked distance education as well. This paper describes the experiences from two years of Internet-mediated project work in a new...... Master of Information Technology education. The main conclusions are, that the project work is a strong learning motivator, enhancing peer collaboration, for off-campus students as well. However, the concept cannot be directly transferred to off-campus learning. The main reasons are that the students...... must communicate electronically, and that they are under a fierce time strain, studying part time and typically with a full time job and a family. In this paper, the main problems experienced with group organized project work in distance education are described, and some possible solutions are listed...
Group Organized Project Work in Distance Education
Helbo, Jan; Knudsen, Morten; Jensen, Lars Peter
2001-01-01
must communicate electronically, and that they are under a fierce time strain, studying part time and typically with a full time job and a family. In this paper, the main problems experienced with group organized project work in distance education are described, and some possible solutions are listed......Project organized problem based learning is a successful concept for on-campus education at Aalborg University. Recently this "Aalborg concept" has been used in networked distance education as well. This paper describes the experiences from two years of Internet-mediated project work in a new...... Master of Information Technology education. The main conclusions are, that the project work is a strong learning motivator, enhancing peer collaboration, for off-campus students as well. However, the concept cannot be directly transferred to off-campus learning. The main reasons are that the students...
Two dimentional lattice vibrations from direct product representations of symmetry groups
J. N. Boyd
1983-01-01
two dimensional crystals. First, the Born cyclic condition is applied to a double chain composed of coupled linear lattices to obtain a cylindrical arrangement. Then the quadratic Lagrangian function for the system is written in matrix notation. The Lagrangian is diagonalized to yield the natural frequencies of the system. The transformation to achieve the diagonalization was obtained from group theorectic considerations. Next, the techniques developed for the double chain are applied to a square lattice. The square lattice is transformed into the toroidal Ising model. The direct product nature of the symmetry group of the torus reveals the transformation to diagonalize the Lagrangian for the Ising model, and the natural frequencies for the principal directions in the model are obtained in closed form.
Marketing Environment Group Project Stimulates Student Interest.
Nastas, George, III
1984-01-01
Describes the Marketing Environment Group Project to be used by a marketing instructor. Indicates that through this teaching method, students have an increased interest in marketing and a greater understanding of how an organization's marketing strategy must adapt to its changing environment. (JOW)
Quantum Field Theories with Symmetries in the Wilsonian Exact Renormalization Group
Vian, Federica
1999-01-01
The purpose of the present thesis is the implementation of symmetries in the Wilsonian Exact Renormalization Group (ERG) approach. After recalling how the ERG can be introduced in a general theory (i.e. containing both bosons and fermions, scalars and vectors) and having applied it to the massless scalar theory as an example of how the method works, we discuss the formulation of the Quantum Action Principle (QAP) in the ERG and show that the Slavnov-Taylor identities can be directly derived for the cutoff effective action at any momentum scale. Firstly the QAP is exploited to analyse the breaking of dilatation invariance occurring in the scalar theory in this approach. Then we address SU(N) Yang-Mills theory and extensively treat the key issue of the boundary conditions of the flow equation which, in this case, have also to ensure restoration of symmetry for the physical theory. In case of a chiral gauge theory, we show how the chiral anomaly can be obtained in the ERG. Finally, we extend the ERG formulation ...
Revisiting the Lie-group symmetry method for turbulent channel flow with wall transpiration
Khujadze, George
2016-01-01
The Lie-group-based symmetry analysis, as first proposed in Avsarkisov et al. (2014) and then later modified in Oberlack et al. (2015), to generate invariant solutions in order to predict the scaling behavior of a channel flow with uniform wall transpiration, is revisited. By focusing first on the results obtained in Avsarkisov et al. (2014), we failed to reproduce two key results: (i) For different transpiration rates at a constant Reynolds number, the mean velocity profiles (in deficit form) do not universally collapse onto a single curve as claimed. (ii) The universally proposed logarithmic scaling law in the center of the channel does not match the direct numerical simulation (DNS) data for the presented parameter values. In fact, no universal scaling behavior in the center of the channel can be detected from their DNS data, as it is misleadingly claimed in Avsarkisov et al. (2014). Moreover, we will demonstrate that the assumption of a Reynolds-number independent symmetry analysis is not justified for th...
On symmetry groups of a 2D nonlinear diffusion equation with source
Radica Cimpoiasu
2015-04-01
Symmetry analysis of a 2D nonlinear evolutionary equation with mixed spatial derivative and general source term involving the dependent variable and its spatial derivatives is performed. The source terms for which the equation admits nontrivial Lie symmetries are identified for two different forms of the symmetry operator. In one of these cases, the symmetries do not depend on the form of nonlinearities and in the other case, nonlinearities of power, exponential and trigonometric forms are considered. There are no supplementary nonclassical symmetries for the investigated equation. The results reported here generalize the previous results on the 2D heat equation and the 2D Ricci model.
Peer Assessment in Engineering Group Projects
Triantafyllou, Eva; Timcenko, Olga
2014-01-01
Peer review has proved to be beneficial in project-based environments by involving students in the process and encouraging them to take ownership of their learning. This article reviews how peer assessment has been employed within group work for different engineering programs. Since...... the administrative burden is one of the common reported challenges of peer assessment, computer assisted peer assessment is also briefly reviewed. Finally, opportunities and challenges in applying peer assessment in a project-based creative engineering program are presented based on the review of the literature....
Group momentum space and Hopf algebra symmetries of point particles coupled to 2+1 gravity
Arzano, Michele; Lotito, Matteo
2014-01-01
We present an in-depth investigation of the $SL(2,\\mathbb{R})$ momentum space describing point particles coupled to Einstein gravity in three space-time dimensions. We introduce different sets of coordinates on the group manifold and discuss their properties under Lorentz transformations. In particular we show how a certain set of coordinates exhibits an upper bound on the energy under deformed Lorentz boosts which saturate at the Planck energy. We discuss how this deformed symmetry framework is generally described by a quantum deformation of the Poincar\\'e group: the quantum double of $SL(2,\\mathbb{R})$. We then illustrate how the space of functions on the group manifold momentum space has a dual representation on a non-commutative space of coordinates via a (quantum) group Fourier transform. In this context we explore the connection between Weyl maps and different notions of (quantum) group Fourier transform appeared in the literature in the past years and establish relations between them. Finally we write ...
The symmetry group and harmonic potentials of an electrostatic generalized multipole
李钰
1995-01-01
The concept of an electrostatic ordinary multipole has been extended to an electrostatic generalized multipole which consists of a pair of close placed electrostatic ordinary multipole and electrostatic round lens. The definition of the M function for an electrostatic ordinary multipole has been extended to that of the M function for an electrostatic generalized multipole. The relation between the symmetry group of anelectrostaticordinary multipole and that of its corresponding electrostatic generalized multipole, and the relation between their constraint relations among their mth partial harmonic potentials have been derived. By analyzing some important electrostatic generalized multipoles, it is concluded that if an electrostatic deflector-multipole and an electrostatic round lens are placed close to each other , one cannot assert that this combined system can always be treated by the aberration theory of a combined focusing-deflection system.
Quinto, A. G.; Ferrari, A. F.; Lehum, A. C.
2016-06-01
In this work, we investigate the consequences of the Renormalization Group Equation (RGE) in the determination of the effective superpotential and the study of Dynamical Symmetry Breaking (DSB) in an N = 1 supersymmetric theory including an Abelian Chern-Simons superfield coupled to N scalar superfields in (2 + 1) dimensional spacetime. The classical Lagrangian presents scale invariance, which is broken by radiative corrections to the effective superpotential. We calculate the effective superpotential up to two-loops by using the RGE and the beta functions and anomalous dimensions known in the literature. We then show how the RGE can be used to improve this calculation, by summing up properly defined series of leading logs (LL), next-to-leading logs (NLL) contributions, and so on... We conclude that even if the RGE improvement procedure can indeed be applied in a supersymmetric model, the effects of the consideration of the RGE are not so dramatic as it happens in the non-supersymmetric case.
Hierarchy of kissing numbers for exceptional Lie symmetry groups in high energy physics
El Naschie, M.S. [Donghua University, Shanghai (China); Department of Physics University of Alexandria, Alexandria (Egypt)], E-mail: Chaossf@aol.com
2008-01-15
We are constructing a hierarchy of kissing numbers representing singular contact points of hyper-spheres in exceptional Lie symmetry groups lattice arrangement embedded in the 26 dimensional bosonic strings spacetime. That way we find a total number of points and dimensions equal to 548. This is 52 more than the order of E{sub 8}E{sub 8} of heterotic string theory and leads to the prediction of 69 elementary particles at an energy scale under 1 T. In other words, our mathematical model predicts nine more particles than what is currently experimentally known to exist in the standard model of high energy physics namely only 60. The result is thus in full agreement with all our previous theoretical findings.
Symmetry fractionalization and twist defects
Tarantino, Nicolas; Lindner, Netanel H.; Fidkowski, Lukasz
2016-03-01
Topological order in two-dimensions can be described in terms of deconfined quasiparticle excitations—anyons—and their braiding statistics. However, it has recently been realized that this data does not completely describe the situation in the presence of an unbroken global symmetry. In this case, there can be multiple distinct quantum phases with the same anyons and statistics, but with different patterns of symmetry fractionalization—termed symmetry enriched topological order. When the global symmetry group G, which we take to be discrete, does not change topological superselection sectors—i.e. does not change one type of anyon into a different type of anyon—one can imagine a local version of the action of G around each anyon. This leads to projective representations and a group cohomology description of symmetry fractionalization, with the second cohomology group {H}2(G,{{ A }}{{abelian}}) being the relevant group. In this paper, we treat the general case of a symmetry group G possibly permuting anyon types. We show that despite the lack of a local action of G, one can still make sense of a so-called twisted group cohomology description of symmetry fractionalization, and show how this data is encoded in the associativity of fusion rules of the extrinsic ‘twist’ defects of the symmetry. Furthermore, building on work of Hermele (2014 Phys. Rev. B 90 184418), we construct a wide class of exactly-solvable models which exhibit this twisted symmetry fractionalization, and connect them to our formal framework.
Gao Ya-Jun
2006-01-01
The so-called extended hyperbolic complex (EHC) function method is used to study further the stationary axisymmetric Einstein-Maxwell theory with p Abelian gauge fields (EM-p theory, for short). Two EHC structural Riemann-Hilbert(RH) transformations are constructed and are then shown to give an infinite-dimensional symmetry group of the EM-p theory. This symmetry group is verified to have the structure of semidirect product of Kac-Moody group SU(p + 1, 1) and Virasoro group. Moreover, the infinitesimal forms of these two RH transformations are calculated and found to give exactly the same infinitesimal transformations as in previous author's paper by a different scheme. This demonstrates that the results obtained in the present paper provide some exponentiations of all the infinitesimal symmetry transformations obtained before.
Effect of a Collective Project on Group Cohesion.
Shipley, Robert H.
Immediately before their second group therapy session, 10 newly formed inpatient therapy groups were randomly assigned to complete either collective or individual art projects. The members of a group in the collective-project condition completed a single art project as a group. Each member of a group assigned to the individual project condition…
Seiler, Christian; Evers, Ferdinand
2016-10-01
A formalism for electronic-structure calculations is presented that is based on the functional renormalization group (FRG). The traditional FRG has been formulated for systems that exhibit a translational symmetry with an associated Fermi surface, which can provide the organization principle for the renormalization group (RG) procedure. We here advance an alternative formulation, where the RG flow is organized in the energy-domain rather than in k space. This has the advantage that it can also be applied to inhomogeneous matter lacking a band structure, such as disordered metals or molecules. The energy-domain FRG (ɛ FRG) presented here accounts for Fermi-liquid corrections to quasiparticle energies and particle-hole excitations. It goes beyond the state of the art G W -BSE , because in ɛ FRG the Bethe-Salpeter equation (BSE) is solved in a self-consistent manner. An efficient implementation of the approach that has been tested against exact diagonalization calculations and calculations based on the density matrix renormalization group is presented. Similar to the conventional FRG, also the ɛ FRG is able to signalize the vicinity of an instability of the Fermi-liquid fixed point via runaway flow of the corresponding interaction vertex. Embarking upon this fact, in an application of ɛ FRG to the spinless disordered Hubbard model we calculate its phase boundary in the plane spanned by the interaction and disorder strength. Finally, an extension of the approach to finite temperatures and spin S =1 /2 is also given.
Field cage development for a time-projection chamber to constrain the nuclear symmetry energy
Estee, J.; Barney, J.; Chajecki, Z.; Famiano, M.; Dunn, J.; Lu, F.; Lynch, W. G.; McIntosh, A. B.; Isobe, T.; Murakami, T.; Sakurai, H.; Shane, R.; Taketani, A.; Tangwancharoen, S.; Tsang, M. B.; Yennello, S.
2012-10-01
The SAMURAI time-projection chamber (sTPC) is being developed for use in the dipole magnet of the newly-commissioned SAMURAI spectrometer at the RIBF facility in Japan. The main scientific objective of the sTPC is to provide constraints on the nuclear symmetry energy at supra-saturation densities. The TPC allows for tracking and identification of light charged particles such as pions, protons, tritons and ^3He. The sTPC must have a Cartesian geometry to match the symmetry of the dipole magnet. The walls of the field cage (FC) detector volume consist of sections of rigid, two-layer circuit boards. Inside and outside copper strips form decreasing equipotentials via a resistor chain, and create a uniform electric field with a maximum of 400 V/cm. The FC volume is hermetically sealed from the enclosure volume to create an insulation volume which can be filled with dry N2 to inhibit corona discharge. I will be presenting the current status of the design and assembly of the sTPC field cage.
Reduction by Lie Group Symmetries in Diffeomorphic Image Registration and Deformation Modelling
Stefan Sommer
2015-05-01
Full Text Available We survey the role of reduction by symmetry in the large deformation diffeomorphic metric mapping framework for registration of a variety of data types (landmarks, curves, surfaces, images and higher-order derivative data. Particle relabelling symmetry allows the equations of motion to be reduced to the Lie algebra allowing the equations to be written purely in terms of the Eulerian velocity field. As a second use of symmetry, the infinite dimensional problem of finding correspondences between objects can be reduced for a range of concrete data types, resulting in compact representations of shape and spatial structure. Using reduction by symmetry, we describe these models in a common theoretical framework that draws on links between the registration problem and geometric mechanics. We outline these constructions and further cases where reduction by symmetry promises new approaches to the registration of complex data types.
Seiler, Christian
2016-01-01
A formalism for electronic-structure calculations is presented that is based on the functional renormalization group (FRG). The traditional FRG has been formulated for systems that exhibit a translational symmetry with an associated Fermi surface, which can provide the organization principle for the renormalization group (RG) procedure. We here advance an alternative formulation, where the RG-flow is organized in the energy-domain rather than in k-space. This has the advantage that it can also be applied to inhomogeneous matter lacking a band-structure, such as disordered metals or molecules. The energy-domain FRG ({\\epsilon}FRG) presented here accounts for Fermi-liquid corrections to quasi-particle energies and particle-hole excitations. It goes beyond the state of the art GW-BSE, because in {\\epsilon}FRG the Bethe-Salpeter equation (BSE) is solved in a self-consistent manner. An efficient implementation of the approach that has been tested against exact diagonalization calculations and calculations based on...
Homological Mirror Symmetry for Calabi-Yau hypersurfaces in projective space
Sheridan, Nicholas
2011-01-01
We prove Homological Mirror Symmetry for a smooth d-dimensional Calabi-Yau hypersurface in projective space, for any d > 2 (for example, d = 3 is the quintic three-fold). The main techniques involved in the proof are: the construction of an immersed Lagrangian sphere in the `d-dimensional pair of pants'; the introduction of the `relative Fukaya category', and an understanding of its grading structure; a description of the behaviour of this category with respect to branched covers (via an `orbifold' Fukaya category); a Morse-Bott model for the relative Fukaya category that allows one to make explicit computations; and the introduction of certain graded categories of matrix factorizations mirror to the relative Fukaya category.
Dynamical symmetries of the Kepler problem
Cariglia, Marco
2013-01-01
This work originates from a first year undergraduate research project on hidden symmetries of the dynamics for classical Hamiltonian systems, under the program 'Jovens talentos para a Ciencia' of Brazilian funding agency Capes. For pedagogical reasons the main subject chosen was Kepler's problem of motion under a central potential, since it is a completely solved system. It is well known that for this problem the group of dynamical symmetries is strictly larger than the isometry group O(3), the extra symmetries corresponding to hidden symmetries of the dynamics. By taking the point of view of examining the group action of the dynamical symmetries on the allowed trajectories, it is possible to teach in the same project basic elements of as many important subjects in physics as: Hamiltonian formalism, hidden symmetries, integrable systems, group theory, and the use of manifolds.
Guo, Jian-You; Chen, Shou-Wan; Niu, Zhong-Ming; Li, Dong-Peng; Liu, Quan
2014-02-14
Symmetry is an important and basic topic in physics. The similarity renormalization group theory provides a novel view to study the symmetries hidden in the Dirac Hamiltonian, especially for the deformed system. Based on the similarity renormalization group theory, the contributions from the nonrelativistic term, the spin-orbit term, the dynamical term, the relativistic modification of kinetic energy, and the Darwin term are self-consistently extracted from a general Dirac Hamiltonian and, hence, we get an accurate description for their dependence on the deformation. Taking an axially deformed nucleus as an example, we find that the self-consistent description of the nonrelativistic term, spin-orbit term, and dynamical term is crucial for understanding the relativistic symmetries and their breaking in a deformed nuclear system.
Symmetries, Symmetry Breaking, Gauge Symmetries
Strocchi, Franco
2015-01-01
The concepts of symmetry, symmetry breaking and gauge symmetries are discussed, their operational meaning being displayed by the observables {\\em and} the (physical) states. For infinitely extended systems the states fall into physically disjoint {\\em phases} characterized by their behavior at infinity or boundary conditions, encoded in the ground state, which provide the cause of symmetry breaking without contradicting Curie Principle. Global gauge symmetries, not seen by the observables, are nevertheless displayed by detectable properties of the states (superselected quantum numbers and parastatistics). Local gauge symmetries are not seen also by the physical states; they appear only in non-positive representations of field algebras. Their role at the Lagrangian level is merely to ensure the validity on the physical states of local Gauss laws, obeyed by the currents which generate the corresponding global gauge symmetries; they are responsible for most distinctive physical properties of gauge quantum field ...
Beyer, Florian; Frauendiener, Jörg
2015-01-01
We apply a single patch pseudo-spectral scheme based on integer spin-weighted spherical harmonics presented in [1, 2] to Einstein's equations. The particular hyperbolic reduction of Einstein's equations which we use is obtained by a covariant version of the generalized harmonic formalism and Geroch's symmetry reduction. In this paper we focus on spacetimes with a spatial S3-topology and symmetry group U(1). We discuss analytical and numerical issues related to our implementation. As a test, we reproduce numerically exact inhomogeneous cosmological solutions of the vacuum Einstein field equations obtained in [3].
Gender and legitimacy in student project groups
Christensen, Gerd
also found that some of the positive and negative characteristics were linked to the students due to their gender. Through the argument that female students talk too much or are having difficulty in coping with criticism, male students refused to cooperate with the female students. Conversely, the male...... students, who were few in the educations I studied, were quite in demand. For me it was very surprising to find these stereotypical perceptions and reasoning among young people in contemporary (and quite progressive) Danish educations. And the question is what it means for the students’ possibilities...... of completing their education. In my presentation I will unfold and discuss the ways in which the students attributed and disclaimed legitimacy to each other qua gender and thus how gender was linked to the relationship between inclusion and exclusion in the student project groups....
Dual identity, in-group projection, and out-group feelings among ethnic minority groups
Verkuyten, Maykel; Martinovic, Borja
2016-01-01
This study extends research on dual identity and in-group projection by considering category prototypicality and indispensability, and by focusing on ethnic minority members and their attitudes towards the native majority and minority out-groups. Among a sample of 491 participants of the three large
Potential energy curves for Mo2: multi-component symmetry-projected Hartree-Fock and beyond
Bytautas, Laimutis; Jiménez-Hoyos, Carlos A.; Rodríguez-Guzmán, R.; Scuseria, Gustavo E.
2014-07-01
The molybdenum dimer is an example of a transition metal system with a formal sextuple bond that constitutes a challenging case for ab initio quantum chemistry methods. In particular, the complex binding pattern in the Mo2 molecule requires a high-quality description of non-dynamic and dynamic electron correlation in order to yield the correct shape of the potential energy curve. The present study examines the performance of a recently implemented multi-component symmetry projected Hartree-Fock (HF) approach. In this work, the spin and spatial symmetries of a trial wavefunction written in terms of non-orthogonal Slater determinants are deliberately broken and then restored in a variation-after-projection framework. The resulting symmetry-projected HF wavefunctions, which possess well-defined quantum numbers, can account for static and some dynamic correlations. A single symmetry-projected configuration in a D∞hS-UHF or a D∞hKS-UHF framework offers a reasonable description of the potential energy curve of Mo2, though the binding energy is too small for the former. Our multi-component strategy offers a way to improve on the single configuration result in a systematic way towards the exact wavefunction: in the def2-TZVP basis set considered in this study, a 7-determinant multi-component D∞hS-UHF approach yields a bond length of 2.01 Å, in good agreement with experimental results, while the predicted binding energy is 39.2 mhartree. The results of this exploratory study suggest that a multi-component symmetry-projected HF stategy is a promising alternative in a high-accuracy description of the electronic structure of challenging systems. We also present and discuss some benchmark calculations based on the CEEIS-FCI (correlation energy extrapolation by intrinsic scaling - full configuration interaction) method for selected geometries.
Deriving diffeomorphism symmetry
Kleppe, Astri
2014-01-01
In an earlier article, we have "derived" space, as a part of the Random Dynamics project. In order to get locality we need to obtain reparametrization symmetry, or equivalently, diffeomorphism symmetry. There we sketched a procedure for how to get locality by first obtaining reparametrization symmetry, or equivalently, diffeomorphism symmetry. This is the object of the present article.
Yale, Paul B
2012-01-01
This book is an introduction to the geometry of Euclidean, affine, and projective spaces with special emphasis on the important groups of symmetries of these spaces. The two major objectives of the text are to introduce the main ideas of affine and projective spaces and to develop facility in handling transformations and groups of transformations. Since there are many good texts on affine and projective planes, the author has concentrated on the n-dimensional cases.Designed to be used in advanced undergraduate mathematics or physics courses, the book focuses on ""practical geometry,"" emphasi
Wang, Juven; Gu, Zheng-Cheng; Wen, Xiao-Gang
The challenge of identifying symmetry-protected topological states (SPTs) is due to their lack of symmetry-breaking order parameters and intrinsic topological orders. For this reason, it is impossible to formulate SPTs under Ginzburg-Landau theory or probe SPTs via fractionalized bulk excitations and topology-dependent ground state degeneracy. However, the partition functions from path integrals with various symmetry twists are universal SPT invariants, fully characterizing SPTs. In this work, we use gauge fields to represent those symmetry twists in closed spacetimes of any dimensionality and arbitrary topology. This allows us to express the SPT invariants in terms of continuum field theory. We show that SPT invariants of pure gauge actions describe the SPTs predicted by group cohomology, while the mixed gauge-gravity actions describe the beyond-group-cohomology SPTs, recently observed by Kapustin. We find new examples of mixed gauge-gravity actions for U(1) SPTs in 3+1D and 4+1D via the Stiefel-Whitney class and the gravitational Chern-Simons term. [Work based on Phys. Rev. Lett. 114, 031601 (2015) arXiv:1405.7689
Teaching Small Group Communication: The Do Good Project
Minei, Elizabeth M.
2016-01-01
This paper focuses on the parameters of a semester-long project called the "Do Good" project, geared towards developing small group communication skills in undergraduate students. This project highlights participation in a social engagement project that allows students to bridge concepts learned in small group communication lectures…
Group Project Support Agents for Helping Students Work Online.
Whatley, Janice; Staniford, Geof; Beer, Martin; Scown, Phil
1999-01-01
Discusses group projects in distance learning, describes factors affecting the successful completion of group projects, and considers whether agent technology (self-contained, concurrently executing software processes that encapsulate the current state in terms of knowledge) is able to support students doing group projects. (LRW)
SπRIT: A time-projection chamber for symmetry-energy studies
Shane, R. [NSCL and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); McIntosh, A.B. [Cyclotron Institute, Texas A& M University, College Station, TX 77843 (United States); Isobe, T. [RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351‐0198 (Japan); Lynch, W.G., E-mail: lynch@nscl.msu.edu [NSCL and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Baba, H. [RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351‐0198 (Japan); Barney, J.; Chajecki, Z. [NSCL and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Chartier, M. [Department of Physics, University of Liverpool, Liverpool, Merseyside, L69 7ZE (United Kingdom); Estee, J. [NSCL and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Famiano, M. [Department of Physics, Western Michigan University, Kalamazoo, MI 49008-5252 (United States); Hong, B. [Department of Physics, Korea University, Seoul 136-701 (Korea, Republic of); Ieki, K. [Department of Physics, Rikkyo University, Toshima‐ku, Tokyo 171‐8501 (Japan); Jhang, G. [Department of Physics, Korea University, Seoul 136-701 (Korea, Republic of); Lemmon, R. [Nuclear Physics Group, STFC Daresbury Laboratory, Daresbury, Cheshire WA4 4AD (United Kingdom); Lu, F. [NSCL and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Shanghai Institute of Applied Physics, CAS, Shanghai 201800 (China); Murakami, T.; Nakatsuka, N. [Department of Physics, Kyoto University, Kita-shirakawa, Kyoto 606-8502 (Japan); Nishimura, M. [RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351‐0198 (Japan); Olsen, R. [Cyclotron Institute, Texas A& M University, College Station, TX 77843 (United States); Powell, W. [Department of Physics, University of Liverpool, Liverpool, Merseyside, L69 7ZE (United Kingdom); and others
2015-06-01
A time-projection chamber (TPC) called the SAMURAI Pion-Reconstruction and Ion-Tracker (SπRIT) has recently been constructed at Michigan State University as part of an international effort to constrain the symmetry-energy term in the nuclear Equation of State (EoS). The SπRIT TPC will be used in conjunction with the SAMURAI spectrometer at the Radioactive Isotope Beam Factory (RIBF) at RIKEN to measure yield ratios for pions and other light isospin multiplets produced in central collisions of neutron-rich heavy ions, such as {sup 132}Sn+{sup 124}Sn. The SπRIT TPC can function both as a TPC detector and as an active target. It has a vertical drift length of 50 cm, parallel to the magnetic field. Gas multiplication is achieved through the use of a multi-wire anode plane. Image charges, produced in the 12096 pads, are read out with the recently developed Generic Electronics for TPCs.
S$\\pi$RIT: A time-projection chamber for symmetry-energy studies
Shane, R; Isobe, T; Lynch, W G; Baba, H; Barney, J; Chajecki, Z; Chartier, M; Estee, J; Famiano, M; Hong, B; Ieki, K; Jhang, G; Lemmon, R; Lu, F; Murakami, T; Nakatsuka, N; Nishimura, M; Olsen, R; Powell, W; Sakurai, H; Taketani, A; Tangwancharoen, S; Tsang, M B; Usukura, T; Wang, R; Yennello, S J; Yurkon, J
2014-01-01
A Time-Projection Chamber (TPC) called the SAMURAI Pion-Reconstruction and Ion-Tracker (S$\\pi$RIT) has recently been constructed at Michigan State University as part of an international effort to constrain the symmetry-energy term in the nuclear Equation of State (EoS). The S$\\pi$RIT TPC will be used in conjunction with the SAMURAI spectrometer at the Radioactive Isotope Beam Factory (RIBF) at RIKEN to measure yield ratios for pions and other light isospin multiplets produced in central collisions of neutron-rich heavy ions, such as $^{132}$Sn + $^{124}$Sn. The S$\\pi$RIT TPC can function both as a TPC detector and as an active target. It has a vertical drift length of 50 cm, parallel to the magnetic field. Gas multiplication is achieved through the use of a multi-wire anode. Image charges are produced in the 12096 pads, and are read out with the recently developed Generic Electronics for TPCs.
A Phase Transformation with no Change in Space Group Symmetry: Octafluoronaphtalene
Pawley, G. S.; Dietrich, O. W.
1975-01-01
, the shear movement being equal to one carbon-carbon bond of the naphthalene skeleton. In this process the molecules reorient, but are still related by the same symmetry operations. This transformation, although not unique, is probably the first of its kind to be discovered in molecular systems....
Jaffé, Hans H
1977-01-01
This book, devoted exclusively to symmetry in chemistry and developed in an essentially nonmathematical way, is a must for students and researchers. Topics include symmetry elements and operations, multiple symmetry operations, multiplication tables and point groups, group theory applications, and crystal symmetry. Extensive appendices provide useful tables.
Henley, E.M.
1981-09-01
Internal and space-time symmetries are discussed in this group of lectures. The first of the lectures deals with an internal symmetry, or rather two related symmetries called charge independence and charge symmetry. The next two discuss space-time symmetries which also hold approximately, but are broken only by the weak forces; that is, these symmetries hold for both the hadronic and electromagnetic forces. (GHT)
CIneGlobe Festival 2015 - Opening Night with projection of Symmetry
Brice, Maximilien
2015-01-01
Swiss Avant-PremièreSymmetry, by Ruben Van Leer (documentary, 28’, EN/ST FR) followed by Symmetry Unravelled, by Juliette Stevens (documentary, 23’, EN/ST FR) in the presence of the directors. Symmetry is a dance & opera film, in which CERN researcher Lukas is thrown off balance, while working on the theory of everything and the smallest particle. Through Claron’s singing he rediscovers love, in an endless landscape. She takes him back to the moment before the big bang, when time didn’t exist; a love with no end… Symmetry Unravelled shows the making of process of Symmetry. It’s filmed deep under the ground inside CERN and it’s detectors and far above sea level on the endless Bolivian miniral landscape Uyuni. Collaborating artists and renowned physicists unravel the relationship between art and science.
Integrated Project Support Study Group : findings
De Jonghe, J; Purvis, J; Smith, T; Van Uytvinck, E
2006-01-01
The challenges of the LHC project have lead CERN to produce a comprehensive set of project management tools covering engineering data management, project scheduling and costing, event management and document management. Each of these tools represents a significant and world-recognised advance in their respective domains. Reviewing the offering on the eve of LHC commissioning one can identify three major challenges: 1. How to integrate the tools to provide a uniform and integrated full-product lifecycle solution 2. How to evolve the functionality in certain areas to address weaknesses identified with our experience in constructing the LHC and integrate emerging industry best practices 3. How to coherently package the offering not just for future projects in CERN, but moreover in the context of providing a centre of excellence for worldwide collaboration in future HEP projects.
Baena, J D; Marques, R
2007-01-01
In this paper a systematic approach to the design of bulk isotropic magnetic metamaterials is presented. The role of the symmetries of both the constitutive element and the lattice are analyzed. For this purpose it is assumed that the metamaterial is composed by cubic SRR resonators, arranged in a cubic lattice. The minimum symmetries needed to ensure an isotropic behavior are analyzed, and some particular configurations are proposed. Besides, an equivalent circuit model is proposed for the considered cubic SRR resonators. Experiments are carried out in order to validate the proposed theory. We hope that this analysis will pave the way to the design of bulk metamaterials with strong isotropic magnetic response, including negative permeability and left-handed metamaterials.
Account of Nonpolynomial SU(3)-Breaking Effects By Use of Quantum Groups As Flavor Symmetries
Gavrilik, A M
1998-01-01
Using instead of ordinary flavour symmetries SU(n_f) their corresponding quantum (q-deformed) analogs yields new baryon mass sum rules of extreme accuracy. We show, in the 3-flavour case, that such approach accounts for highly nonlinear (nonpolynomial) SU(3)-breaking effects both in the octet and decuplet baryon masses. A version of this approach is considered that involves q-covariant ingredients in the mass operator. The resulting new 'q-deformed' mass relation (q-MR) is simpler than previously derived q-MRs, but requires, for its empirical validity, a fitting to fix the value of the deformation parameter q. Well-known Gell-Mann--Okubo (GMO) octet mass sum rule is found to result not only from usual SU(3), but also from some exotic symmetry corresponding to the q=-1 (i.e., singular) limit of the q-algebra U_q(su_3).
International Group Heterogeneity and Students' Business Project Achievement
Ding, Ning; Bosker, Roel J.; Xu, Xiaoyan; Rugers, Lucie; van Heugten, Petra PAM
2015-01-01
In business higher education, group project work plays an essential role. The purpose of the present study is to explore the relationship between the group heterogeneity of students' business project groups and their academic achievements at both group and individual levels. The sample consists of 536 freshmen from an International Business School…
Teaching Small Group Communication: A Do Good Project
Elizabeth M. Minei, PhD
2016-08-01
Full Text Available This paper focuses on the parameters of a semester-long project called the “Do Good” project, geared towards developing small group communication skills in undergraduate students. This project highlights participation in a social engagement project that allows students to bridge concepts learned in small group communication lectures (e.g., team dynamics, project management, conflict resolution, decision making, leadership with community outreach. Included are an overview of the project, and examples for how each component both challenges students’ ability to communicate in groups and provides motivation that foster students’ ability to link in-class knowledge with practical, real world application.
Dealing with Parasites in Group Projects.
Carter, Judy H.
While it is generally accepted that people working in groups can accomplish more than people working individually, it is equally accepted that parasites will attempt to feed on the other group members. Group work has been called by several names--group learning, cooperative learning, collaborative learning--all of which carry slightly different…
Beyer, F.; Escobar, L.; Frauendiener, J.
2016-02-01
In this paper we consider the single patch pseudospectral scheme for tensorial and spinorial evolution problems on the 2-sphere presented by Beyer et al. [Classical Quantum Gravity 32, 175013 (2015); Classical Quantum Gravity31, 075019 (2014)], which is based on the spin-weighted spherical harmonics transform. We apply and extend this method to Einstein's equations and certain classes of spherical cosmological spacetimes. More specifically, we use the hyperbolic reductions of Einstein's equations obtained in the generalized wave map gauge formalism combined with Geroch's symmetry reduction, and focus on cosmological spacetimes with spatial S3 -topologies and symmetry groups U(1) or U (1 )×U (1 ) . We discuss analytical and numerical issues related to our implementation. We test our code by reproducing the exact inhomogeneous cosmological solutions of the vacuum Einstein field equations obtained by Beyer and Hennig [Classical Quantum Gravity 31, 095010 (2014)].
Lattice Regularization and Symmetries
Hasenfratz, Peter; Von Allmen, R; Allmen, Reto von; Hasenfratz, Peter; Niedermayer, Ferenc
2006-01-01
Finding the relation between the symmetry transformations in the continuum and on the lattice might be a nontrivial task as illustrated by the history of chiral symmetry. Lattice actions induced by a renormalization group procedure inherit all symmetries of the continuum theory. We give a general procedure which gives the corresponding symmetry transformations on the lattice.
CP and other Symmetries of Symmetries
Trautner, Andreas
2016-01-01
Outer automorphisms of symmetries ("symmetries of symmetries") in relativistic quantum field theories are studied, including charge conjugation (C), space-reflection (P) , and time-reversal (T) transformations. The group theory of outer automorphisms is pedagogically introduced and it is shown that CP transformations are special outer automorphisms of the global, local, and space-time symmetries of a theory. It is shown that certain discrete groups allow for a group theoretical prediction of parameter independent CP violating complex phases with fixed geometrical values. The remainder of this thesis pioneers the study of outer automorphisms which are not related to C, P, or T. It is shown how outer automorphisms, in general, relate symmetry invariants and, in theories with spontaneous symmetry breaking, imply relations between different vacuum expectation values. Thereby, outer automorphisms can give rise to emergent symmetries. An example model with a discrete symmetry and three copies of the Standard Model ...
Low energy phenomena in a model with symmetry group SUSY SO (10) ×△(48)×U(1)
周光召; 吴岳良
1996-01-01
Fermion masses and mixing angles including that of neutrinos are studied in a model with symmetry group SUSY S0(10) x4(48) xU(i). Universality of Yukawa coupling of superfields is assumed. The resulting texture of mass matrices in the low energy region depends only on a single coupling constant and VEVs caused by necessary symmetry breaking. 13 parameters involving masses and mixing angles in the quark and charged lepton sector are successfully described by only five parameters with two of them determined by the scales of U(1), SO (10) and SU(5) symmetry breaking compatible with the requirement of grand unification and proton decay. The neutrino masses and mixing angles in the leptonic sector are also determined with the addition of a Majorana coupling term. It is found that LSND, events, atmospheric neutrino deficit and the mass limit put by hot dark matter can be naturally explained. Solar neutrino puzzle can be solved only by introducing sterile neutrino with one additional parameter. More precise me
Quasi-projectivity, Artin-Tits Groups, and Pencil Maps
Bartolo, Enrique Artal; Matei, Daniel
2010-01-01
We consider the problem of deciding if a group is the fundamental group of a smooth connected complex quasi-projective (or projective) variety using Alexander-based invariants. In particular, we solve the problem for large families of Artin-Tits groups. We also study finiteness properties of such groups and exhibit examples of hyperplane complements whose fundamental groups satisfy $\\text{F}_{k-1}$ but not $\\text{F}_k$ for any $k$.
Groups That Work: Student Achievement in Group Research Projects and Effects on Individual Learning
Monson, Renee
2017-01-01
Group research projects frequently are used to teach undergraduate research methods. This study uses multivariate analyses to examine the characteristics of higher-achieving groups (those that earn higher grades on group research projects) and to estimate the effects of participating in higher-achieving groups on subsequent individual learning…
Chubukov, A. V.
2009-05-01
We analyze antiferromagnetism and superconductivity in novel Fe-based superconductors within the weak-coupling, itinerant model of electron and hole pockets near (0, 0) and ( π, π) in the folded Brillouin zone. We discuss the interaction Hamiltonian, the nesting, the RG flow of the couplings at energies above and below the Fermi energy, and the interplay between SDW magnetism, superconductivity and charge orbital order. We argue that SDW antiferromagnetism wins at zero doping but looses to superconductivity upon doping. We show that the most likely symmetry of the superconducting gap is A1 g in the folded zone. This gap has no nodes on the Fermi surface but changes sign between hole and electron pockets. We also argue that at weak coupling, this pairing predominantly comes not from spin fluctuation exchange but from a direct pair hopping between hole and electron pockets.
Van Isacker, P
2010-01-01
The use of dynamical symmetries or spectrum generating algebras for the solution of the nuclear many-body problem is reviewed. General notions of symmetry and dynamical symmetry in quantum mechanics are introduced and illustrated with simple examples such as the SO(4) symmetry of the hydrogen atom and the isospin symmetry in nuclei. Two nuclear models, the shell model and the interacting boson model, are reviewed with particular emphasis on their use of group-theoretical techniques.
On the Picard group of a compact flat projective variety
Michelacakis, NJ
1996-01-01
In this note, we describe the Picard group of the class of compact, smooth, flat, projective varieties. In view of Charlap's work and Johnson's characterization, we construct line bundles over such manifolds as the holonomy-invariant elements of the Neron-Severi group of a projective flat torus cove
Group Projects in Chemical Engineering Using a Wiki
Heys, Jeffrey J.
2008-01-01
Group projects are common in undergraduate chemical engineering course. Wikis are a new medium for group projects because they are Webpages that are edited using the same software used to view the Webpage. Advantages include the ability to record changes made by each individual (helpful for grading), ability to continuously monitor progress, and a…
String cohomology groups of complex projective spaces
Ottosen, Iver; Bökstedt, Marcel
2007-01-01
Let X be a space and write LX for its free loop space equipped with the action of the circle group T given by dilation. The equivariant cohomology H*(LXhT;Z/p) is a module over H*(BT;Z/p). We give a computation of this module when X=CPr for any positive integer r and any prime number p. The compu......Let X be a space and write LX for its free loop space equipped with the action of the circle group T given by dilation. The equivariant cohomology H*(LXhT;Z/p) is a module over H*(BT;Z/p). We give a computation of this module when X=CPr for any positive integer r and any prime number p....... The computation does not use the fact that CPr is formal, nor does it use the Jones isomorphism and negative cyclic homology....
Ruf, Armin; Tetaz, Tim; Schott, Brigitte; Joseph, Catherine; Rudolph, Markus G
2016-11-01
Fructose-1,6-bisphosphatase (FBPase) is a key regulator of gluconeogenesis and a potential drug target for type 2 diabetes. FBPase is a homotetramer of 222 symmetry with a major and a minor dimer interface. The dimers connected via the minor interface can rotate with respect to each other, leading to the inactive T-state and active R-state conformations of FBPase. Here, the first crystal structure of human liver FBPase in the R-state conformation is presented, determined at a resolution of 2.2 Å in a tetragonal setting that exhibits an unusual arrangement of noncrystallographic symmetry (NCS) elements. Self-Patterson function analysis and various intensity statistics revealed the presence of pseudo-translation and the absence of twinning. The space group is P41212, but structure determination was also possible in space groups P43212, P4122 and P4322. All solutions have the same arrangement of three C2-symmetric dimers spaced by 1/3 along an NCS axis parallel to the c axis located at (1/4, 1/4, z), which is therefore invisible in a self-rotation function analysis. The solutions in the four space groups are related to one another and emulate a body-centred lattice. If all NCS elements were crystallographic, the space group would be I4122 with a c axis three times shorter and a single FBPase subunit in the asymmetric unit. I4122 is a minimal, non-isomorphic supergroup of the four primitive tetragonal space groups, explaining the space-group ambiguity for this crystal.
Lorenzen, R.
2007-03-15
Starting from the assumption of modular P{sub 1}CT symmetry in quantum field theory a representation of the universal covering of the Poincar'e group is constructed in terms of pairs of modular conjugations. The modular conjugations are associated with field algebras of unbounded operators localised in wedge regions. It turns out that an essential step consists in characterising the universal covering group of the Lorentz group by pairs of wedge regions, in conjunction with an analysis of its geometrical properties. In this thesis two approaches to this problem are developed in four spacetime dimensions. First a realisation of the universal covering as the quotient space over the set of pairs of wedge regions is presented. In spite of the intuitive definition, the necessary properties of a covering space are not straightforward to prove. But the geometrical properties are easy to handle. The second approach takes advantage of the well-known features of spin groups, given as subgroups of Clifford algebras. Characterising elements of spin groups by pairs of wedge regions is possible in an elegant manner. The geometrical analysis is performed by means of the results achieved in the first approach. These geometrical properties allow for constructing a representation of the universal cover of the Lorentz group in terms of pairs of modular conjugations. For this representation the derivation of the spin-statistics theorem is straightforward, and a PCT operator can be defined. Furthermore, it is possible to transfer the results to nets of field algebras in algebraic quantum field theory with ease. Many of the usual assumptions in quantum field theory like the spectrum condition or the existence of a covariant unitary representation, as well as the assumption on the quantum field to have only finitely many components, are not required. For the standard axioms, the crucial assumption of modular P{sub 1}CT symmetry constitutes no loss of generality because it is a
Mörschel, Philipp; Schmidt, Martin U
2015-01-01
A crystallographic quantum-mechanical/molecular-mechanical model (c-QM/MM model) with full space-group symmetry has been developed for molecular crystals. The lattice energy was calculated by quantum-mechanical methods for short-range interactions and force-field methods for long-range interactions. The quantum-mechanical calculations covered the interactions within the molecule and the interactions of a reference molecule with each of the surrounding 12-15 molecules. The interactions with all other molecules were treated by force-field methods. In each optimization step the energies in the QM and MM shells were calculated separately as single-point energies; after adding both energy contributions, the crystal structure (including the lattice parameters) was optimized accordingly. The space-group symmetry was maintained throughout. Crystal structures with more than one molecule per asymmetric unit, e.g. structures with Z' = 2, hydrates and solvates, have been optimized as well. Test calculations with different quantum-mechanical methods on nine small organic molecules revealed that the density functional theory methods with dispersion correction using the B97-D functional with 6-31G* basis set in combination with the DREIDING force field reproduced the experimental crystal structures with good accuracy. Subsequently the c-QM/MM method was applied to nine compounds from the CCDC blind tests resulting in good energy rankings and excellent geometric accuracies.
The symmetry groups of noncommutative quantum mechanics and coherent state quantization
Chowdhury, S. Hasibul Hassan; Ali, S. Twareque [Department of Mathematics and Statistics, Concordia University, Montreal, Quebec H3G 1M8 (Canada)
2013-03-15
We explore the group theoretical underpinning of noncommutative quantum mechanics for a system moving on the two-dimensional plane. We show that the pertinent groups for the system are the two-fold central extension of the Galilei group in (2+1)-space-time dimensions and the two-fold extension of the group of translations of R{sup 4}. This latter group is just the standard Weyl-Heisenberg group of standard quantum mechanics with an additional central extension. We also look at a further extension of this group and discuss its significance to noncommutative quantum mechanics. We build unitary irreducible representations of these various groups and construct the associated families of coherent states. A coherent state quantization of the underlying phase space is then carried out, which is shown to lead to exactly the same commutation relations as usually postulated for this model of noncommutative quantum mechanics.
Follow-groups, Enhancing Learning Potential at Project Exams
Tollestrup, Christian H. T.
2016-01-01
of their project evaluation in relation to the other projects in the class. The investigation shows that following another group’s exam significantly heightens the percentage of students that understand the evaluation of their project related to the other projects in the class. It also has minor positive effects......In the Problem Based, Project Oriented Learning Program of Industrial Design Engineering at AAU students work and are examined/evaluated in groups. Following a period of a 6 years of ban on group-based exams by the government, the return of the group-based exam at Universities in 2014 has...... into perspective by seeing other project exams? So in order to investigate whether there was a possibility to further enhance the learning potential and understanding of the learning outcome the study board for the Architecture & Design program opened for a trial period for 2 semesters for voluntarily organizing...
Symmetry, Symmetry Breaking and Topology
Siddhartha Sen
2010-07-01
Full Text Available The ground state of a system with symmetry can be described by a group G. This symmetry group G can be discrete or continuous. Thus for a crystal G is a finite group while for the vacuum state of a grand unified theory G is a continuous Lie group. The ground state symmetry described by G can change spontaneously from G to one of its subgroups H as the external parameters of the system are modified. Such a macroscopic change of the ground state symmetry of a system from G to H correspond to a “phase transition”. Such phase transitions have been extensively studied within a framework due to Landau. A vast range of systems can be described using Landau’s approach, however there are also systems where the framework does not work. Recently there has been growing interest in looking at such non-Landau type of phase transitions. For instance there are several “quantum phase transitions” that are not of the Landau type. In this short review we first describe a refined version of Landau’s approach in which topological ideas are used together with group theory. The combined use of group theory and topological arguments allows us to determine selection rule which forbid transitions from G to certain of its subgroups. We end by making a few brief remarks about non-Landau type of phase transition.
We Scrum Every Day: Using Scrum Project Management Framework for Group Projects
Pope-Ruark, Rebecca
2012-01-01
Collaborative group projects have documented learning benefits, yet collaboration is challenging for students because the educational system values individual achievement. This article explores Scrum, an approach to framing, planning, and managing group projects used in Web-software development. Designed for multi-faceted projects, this approach…
We Scrum Every Day: Using Scrum Project Management Framework for Group Projects
Pope-Ruark, Rebecca
2012-01-01
Collaborative group projects have documented learning benefits, yet collaboration is challenging for students because the educational system values individual achievement. This article explores Scrum, an approach to framing, planning, and managing group projects used in Web-software development. Designed for multi-faceted projects, this approach…
Frewer, Michael
2016-01-01
The study by Oberlack et al. (2006) consists of two main parts: a direct numerical simulation (DNS) of a turbulent plane channel flow with streamwise rotation and a preceding Lie-group symmetry analysis on the two-point correlation equation (TPC) to analytically predict the scaling of the mean velocity profiles for different rotation rates. We will only comment on the latter part, since the DNS result obtained in the former part has already been commented on by Recktenwald et al. (2009), stating that the observed mismatch between DNS and their performed experiment is possibly due to the prescription of periodic boundary conditions on a too small computational domain in the spanwise direction. By revisiting the group analysis part in Oberlack et al. (2006), we will generate more natural scaling laws describing better the mean velocity profiles than the ones proposed. However, due to the statistical closure problem of turbulence, this improvement is illusive. As we will demonstrate, any arbitrary invariant scal...
Parrish, Robert M; Parker, Trent M; Sherrill, C David
2014-10-14
Recently, we introduced an effective atom-pairwise partition of the many-body symmetry-adapted perturbation theory (SAPT) interaction energy decomposition, producing a method known as atomic SAPT (A-SAPT) [Parrish, R. M.; Sherrill, C. D. J. Chem. Phys. 2014, 141, 044115]. A-SAPT provides ab initio atom-pair potentials for force field development and also automatic visualizations of the spatial contributions of noncovalent interactions, but often has difficulty producing chemically useful partitions of the electrostatic energy, due to the buildup of oscillating partial charges on adjacent functional groups. In this work, we substitute chemical functional groups in place of atoms as the relevant local quasiparticles in the partition, resulting in a functional-group-pairwise partition denoted as functional-group SAPT (F-SAPT). F-SAPT assigns integral sets of local occupied electronic orbitals and protons to chemical functional groups and linking σ bonds. Link-bond contributions can be further assigned to chemical functional groups to simplify the analysis. This approach yields a SAPT partition between pairs of functional groups with integral charge (usually neutral), preventing oscillations in the electrostatic partition. F-SAPT qualitatively matches chemical intuition and the cut-and-cap fragmentation technique but additionally yields the quantitative many-body SAPT interaction energy. The conceptual simplicity, chemical utility, and computational efficiency of F-SAPT is demonstrated in the context of phenol dimer, proflavine(+)-DNA intercalation, and a cucurbituril host-guest inclusion complex.
Stokes, Harold T; Campbell, Branton J; van Smaalen, Sander
2011-01-01
A complete table of (3 + 1)D, (3 + 2)D and (3 + 3)D superspace groups (SSGs) has been enumerated that corrects omissions and duplicate entries in previous tables of superspace groups and Bravais classes. The theoretical methods employed are not new, though the implementation is both novel and robust. The paper also describes conventions for assigning a unique one-line symbol for each group in the table. Finally, a new online data repository is introduced that delivers more complete information about each SSG than has been presented previously.
Systematic analysis of finite family symmetry groups and their application to the lepton sector
Ludl, Patrick Otto
2009-01-01
In this work we will investigate Lagrangians of the standard model extended by three right-handed neutrinos, and the consequences of invariance under finite groups G for lepton masses and mixing matrices are studied. The main part of this thesis is the systematic analysis of finite subgroups of SU(3). The analysis of these groups may act as a toolkit for future model building.
Cheng, Meng; Zaletel, Michael; Barkeshli, Maissam; Vishwanath, Ashvin; Bonderson, Parsa
2016-10-01
The Lieb-Schultz-Mattis theorem and its higher-dimensional generalizations by Oshikawa and Hastings require that translationally invariant 2D spin systems with a half-integer spin per unit cell must either have a continuum of low energy excitations, spontaneously break some symmetries, or exhibit topological order with anyonic excitations. We establish a connection between these constraints and a remarkably similar set of constraints at the surface of a 3D interacting topological insulator. This, combined with recent work on symmetry-enriched topological phases with on-site unitary symmetries, enables us to develop a framework for understanding the structure of symmetry-enriched topological phases with both translational and on-site unitary symmetries, including the effective theory of symmetry defects. This framework places stringent constraints on the possible types of symmetry fractionalization that can occur in 2D systems whose unit cell contains fractional spin, fractional charge, or a projective representation of the symmetry group. As a concrete application, we determine when a topological phase must possess a "spinon" excitation, even in cases when spin rotational invariance is broken down to a discrete subgroup by the crystal structure. We also describe the phenomena of "anyonic spin-orbit coupling," which may arise from the interplay of translational and on-site symmetries. These include the possibility of on-site symmetry defect branch lines carrying topological charge per unit length and lattice dislocations inducing degeneracies protected by on-site symmetry.
Group Projects in Interior Design Studio Classes: Peer Feedback Benefits
Jurado, Juan A.
2011-01-01
Group projects have been shown to be effective for providing peer feedback in classrooms. While students in regular enrollment classes benefit from peer feedback, low-enrollment classes face many challenges. This study compares peer feedback effectiveness between two interior design studio classes with different design projects. In one class,…
Group Projects in Interior Design Studio Classes: Peer Feedback Benefits
Jurado, Juan A.
2011-01-01
Group projects have been shown to be effective for providing peer feedback in classrooms. While students in regular enrollment classes benefit from peer feedback, low-enrollment classes face many challenges. This study compares peer feedback effectiveness between two interior design studio classes with different design projects. In one class,…
Evaluating Projects Based on Intuitionistic Fuzzy Group Decision Making
Babak Daneshvar Rouyendegh
2012-01-01
Full Text Available There are various methods regarding project selection in different fields. This paper deals with an actual application of construction project selection, using two aggregation operators. First, the opinion of experts is used in a model of group decision making called intuitionistic fuzzy TOPSIS (IFT. Secondly, project evaluation is formulated by dynamic intuitionistic fuzzy weighted averaging (DIFWA. Intuitionistic fuzzy weighted averaging (IFWA operator is utilized to aggregate individual opinions of decision makers (DMs for rating the importance of criteria and alternatives. A numerical example for project selection is given to clarify the main developed result in this paper.
Poisson Lie symmetry and D-branes in WZW model on the Heisenberg Lie group $H_4$
Eghbali, A
2015-01-01
We show that the WZW model on the Heisenberg Lie group $H_4$ has Poisson-Lie symmetry only when the dual Lie group is ${ A}_2 \\oplus 2{ A}_1$. In this way, we construct the mutual T-dual sigma models on Drinfel'd double generated by the Heisenberg Lie group $H_4$ and its dual pair, ${ A}_2 \\oplus 2{ A}_1$, as the target space in such a way that the original model is the same as the $H_4$ WZW model. Furthermore, we show that the dual model is conformal up to two loops order. Finally, we discuss $D$-branes and the worldsheet boundary conditions defined by a gluing matrix on the $H_4$ WZW model. Using the duality map obtained from the canonical transformation description of the Poisson-Lie T-duality transformations for the gluing matrix which locally defines the properties of the $D$-brane, we find two different cases of the gluing matrices for the WZW model based on the Heisenberg Lie group $H_4$ and its dual model.
Poisson Lie symmetry and D-branes in WZW model on the Heisenberg Lie group H4
A. Eghbali
2015-10-01
Full Text Available We show that the WZW model on the Heisenberg Lie group H4 has Poisson–Lie symmetry only when the dual Lie group is A2⊕2A1. In this way, we construct the mutual T-dual sigma models on Drinfel'd double generated by the Heisenberg Lie group H4 and its dual pair, A2⊕2A1, as the target space in such a way that the original model is the same as the H4 WZW model. Furthermore, we show that the dual model is conformal up to two-loop order. Finally, we discuss D-branes and the worldsheet boundary conditions defined by a gluing matrix on the H4 WZW model. Using the duality map obtained from the canonical transformation description of the Poisson–Lie T-duality transformations for the gluing matrix which locally defines the properties of the D-brane, we find two different cases of the gluing matrices for the WZW model based on the Heisenberg Lie group H4 and its dual model.
Enhancing Astronomy Major Learning Through Group Research Projects
McGraw, Allison M.; Hardegree-Ullman, K.; Turner, J.; Shirley, Y. L.; Walker-Lafollette, A.; Scott, A.; Guvenen, B.; Raphael, B.; Sanford, B.; Smart, B.; Nguyen, C.; Jones, C.; Smith, C.; Cates, I.; Romine, J.; Cook, K.; Pearson, K.; Biddle, L.; Small, L.; Donnels, M.; Nieberding, M.; Kwon, M.; Thompson, R.; De La Rosa, R.; Hofmann, R.; Tombleson, R.; Smith, T.; Towner, A. P.; Wallace, S.
2013-01-01
The University of Arizona Astronomy Club has been using group research projects to enhance the learning experience of undergraduates in astronomy and related fields. Students work on two projects that employ a peer-mentoring system so they can learn crucial skills and concepts necessary in research environments. Students work on a transiting exoplanet project using the 1.55-meter Kuiper Telescope on Mt. Bigelow in Southern Arizona to collect near-UV and optical wavelength data. The goal of the project is to refine planetary parameters and to attempt to detect exoplanet magnetic fields by searching for near-UV light curve asymmetries. The other project is a survey that utilizes the 12-meter Arizona Radio Observatory on Kitt Peak to search for the spectroscopic signature of infall in nearby starless cores. These are unique projects because students are involved throughout the entire research process, including writing proposals for telescope time, observing at the telescopes, data reduction and analysis, writing papers for publication in journals, and presenting research at scientific conferences. Exoplanet project members are able to receive independent study credit for participating in the research, which helps keep the project on track. Both projects allow students to work on professional research and prepare for several astronomy courses early in their academic career. They also encourage teamwork and mentor-style peer teaching, and can help students identify their own research projects as they expand their knowledge.
Spin-Anisotropy Commensurable Chains Quantum Group Symmetries and N=2 SUSY
Berkovich, A; Sierra, G
1994-01-01
In this paper we consider a class of the 2D integrable models. These models are higher spin XXZ chains with an extra condition of the commensurability between spin and anisotropy. The mathematics underlying this commensurability is provided by the quantum groups with deformation parameter being an Nth root of unity. Our discussion covers a range of topics including new integrable deformations, thermodynamics, conformal behaviour, S-matrices and magnetization. The emerging picture strongly depends on the N-parity. For the N even case at the commensurable point, S-matrices factorize into N=2 supersymmetric Sine-Gordon matrix and an RSOS piece. The physics of the N odd case is rather different. Here, the supersymmetry does not manifest itself and the bootstrap hypothesis fails. Away from the commensurable point, we find an unusual behaviour. The magnetization of our chains depends on the sign of the external magnetic field.
Approximate and renormgroup symmetries
Ibragimov, Nail H. [Blekinge Institute of Technology, Karlskrona (Sweden). Dept. of Mathematics Science; Kovalev, Vladimir F. [Russian Academy of Sciences, Moscow (Russian Federation). Inst. of Mathematical Modeling
2009-07-01
''Approximate and Renormgroup Symmetries'' deals with approximate transformation groups, symmetries of integro-differential equations and renormgroup symmetries. It includes a concise and self-contained introduction to basic concepts and methods of Lie group analysis, and provides an easy-to-follow introduction to the theory of approximate transformation groups and symmetries of integro-differential equations. The book is designed for specialists in nonlinear physics - mathematicians and non-mathematicians - interested in methods of applied group analysis for investigating nonlinear problems in physical science and engineering. (orig.)
A Project Team: a Team or Just a Group?
Kateřina; Daniela; Martina,
2014-01-01
This paper deals with issues related to work in either teams or groups. The theoretical part discusses a team and a group with regards to its definition, classification and basic distinction, brings in more on the typology of team roles, personality assessment and sociometric methods. The analytical part tests the project (work) team of a medical center represented in terms of personality and motivational types, team roles and interpersonal team relations concerning the willingness of coopera...
A Project Team: A Team or Just a Group?
Katerina Hrazdilova Bockova; Daniela Maťovcikova
2013-01-01
This paper deals with issues related to work in either teams or groups. The theoretical part which discusses a team and a group with regards to its definition, classification and basic distinction brings in more on the typology of team roles, personality assessment and sociometric methods. The analytical part tests the project (work) team of a medical center represented in terms of personality and motivational types, team roles and interpersonal team relations concerning t...
Reducing Social Loafing in Group-Based Projects
Perron, Brian E.
2011-01-01
Social loafing in group-based projects is a common problem for college teachers. This problem has received great attention, including a Quick Fix article by Stevens (2007), whose recommendations remain useful today, particularly the mechanism for peer evaluations--a key strategy for reducing social loafing. Since the publication of Stevens's…
Xtranormal Learning for Millennials: An Innovative Tool for Group Projects
Stratton, Micheal T.; Julien, Mark
2014-01-01
Encouraging students to actively engage with course material is an ongoing challenge for many management educators. One common tactic is to use various technologies that allow tech-savvy Millennial Generation students to take a more active role in their learning. In this article, we describe an innovative group project that challenges students to…
Learning Effects of an International Group Competition Project
Akpinar, Murat; del Campo, Cristina; Eryarsoy, Enes
2015-01-01
This study investigates the effects of collaboration and competition on students' learning performance in a course of business statistics. The collaboration involved a simultaneously organised group competition project with analysis of real-life business problems among students. Students from the following schools participated: JAMK University of…
Xtranormal Learning for Millennials: An Innovative Tool for Group Projects
Stratton, Micheal T.; Julien, Mark
2014-01-01
Encouraging students to actively engage with course material is an ongoing challenge for many management educators. One common tactic is to use various technologies that allow tech-savvy Millennial Generation students to take a more active role in their learning. In this article, we describe an innovative group project that challenges students to…
Wang, Fa; Zhai, Hui; Ran, Ying; Vishwanath, Ashvin; Lee, Dung-Hai
2009-01-30
We apply the fermion functional renormalization-group method to determine the pairing symmetry and pairing mechanism of the FeAs-Based materials. Within a five band model with pure repulsive interactions, we find an electronic-driven superconducting pairing instability. For the doping and interaction parameters we have examined, extended s wave, whose order parameter takes on opposite sign on the electron and hole pockets, is always the most favorable pairing symmetry. The pairing mechanism is the inter-Fermi-surface Josephson scattering generated by the antiferromagnetic correlation.
Christodoulides, Kyriakos
2014-07-01
We study single and coupled first-order differential equations (ODEs) that admit symmetries with tangent vector fields, which satisfy the N-dimensional Cauchy-Riemann equations. In the two-dimensional case, classes of first-order ODEs which are invariant under Möbius transformations are explored. In the N dimensional case we outline a symmetry analysis method for constructing exact solutions for conformal autonomous systems. A very important aspect of this work is that we propose to extend the traditional technical usage of Lie groups to one that could provide testable predictions and guidelines for model-building and model-validation. The Lie symmetries in this paper are constrained and classified by field theoretical considerations and their phenomenological implications. Our results indicate that conformal transformations are appropriate for elucidating a variety of linear and nonlinear systems which could be used for, or inspire, future applications. The presentation is pragmatic and it is addressed to a wide audience.
SAMURAI Time-Projection Chamber: A device for constraining the symmetry energy
Shane, R.; Andrews, K.; Barney, J.; Brophy, B.; Chajecki, Z.; Chan, C. F.; Dunn, J. W.; Ersoy, E.; Estee, J.; Gilbert, J.; Lu, F.; Lynch, W. G.; Tsang, M. B.; McIntosh, A. B.; Yennello, S. J.; Dye, S.; Elhoussieny, M.; Famiano, M.; Snow, C.; Isobe, T.; Sakurai, H.; Taketani, A.; Murakami, T.; Powell, W.
2013-04-01
The SAMURAI-TPC is a time-projection chamber to be used in conjunction with the SAMURAI spectrometer at the Radioactive Isotope Beam Facility at RIKEN, Japan. It is designed to detect charged pions as well as light charged particles up to oxygen produced in heavy ion collisions. Design of the TPC is based on the EOS TPC with similar dimensions. However, the TPC will be equipped with the newly designed General Electronics for TPCs (GET). One of the proposed experimental programs using the TPC is to measure pi+/pi- ratios from heavy-ion collisions which should provide constraints on the asymmetry term in the nuclear equation of state at densities about twice saturation density. In this talk, the design and construction of the detector will be discussed.
Group dynamics for the acquisition of competences in Project Management
Taguas, E. V.; Aguilar, M. C.; Castillo, C.; Polo, M. J.; Pérez, R.
2012-04-01
The Bologna Process promotes European citizens' employability from teaching fields in the University which implies the design of activities addressed to the development of skills for the labor market and engagement of employers. This work has been conceived for improving the formation of Engineering Project Management through group dynamics focused on: 1) the use of the creativity for solving problems; 2) promoting leadership capacities and social skills in multidisciplinary/multicultural work groups; 3) the ethical, social and environmental compromise; 4) the continuous learning. Different types of activities were designed: short activities of 15-30 minutes where fragments of books or songs are presented and discussed and long activities (2 h) where groups of students take different roles for solving common problems and situations within the Engineering Projects context. An electronic book with the content of the dynamics and the material for the students has been carried out. A sample of 20 students of Electronic Engineering degree which had participated at least in two dynamics, evaluated the utility for improving their formation in Engineering Project Management with a mark of 8.2 (scale 0-10, standard deviation equal to 0.9). On the other hand, the teachers observed how this type of work, promotes the interdisciplinary training and the acquisition of social skills, usually not-included in the objectives of the subjects.
Brand, T; Böttcher, S; Jahn, I
2015-12-01
The aim of this study was to assess methods used to access target groups in prevention projects funded within the prevention research framework by the German Federal Ministry of Education and Research. A survey with prevention projects was conducted. Access strategies, communication channels, incentives, programme reach, and successful practical recruitment strategies were explored. 38 out of 60 projects took part in the survey. Most projects accessed their target group within structured settings (e. g., child day-care centers, schools, workplaces). Multiple communication channels and incentives were used, with written information and monetary incentives being used most frequently. Only few projects were able to report their programme reach adequately; programme reach was highest for programmes accessing the target groups in structured settings. The respondents viewed active recruitment via personal communication with the target group and key persons in the settings as the most successful strategy. The paper provides an overview on recruitment strategies used in current preven-tion projects. More systematic research on programme reach is necessary. © Georg Thieme Verlag KG Stuttgart · New York.
Johnson, Adam R.
2013-01-01
A molecular orbital (MO) diagram, especially its frontier orbitals, explains the bonding and reactivity for a chemical compound. It is therefore important for students to learn how to construct one. The traditional methods used to derive these diagrams rely on linear algebra techniques to combine ligand orbitals into symmetry-adapted linear…
Postlethwait, Ariana E.
2016-01-01
This study examined the impact of group size, group formation, group conflict, and division of labor on student outcomes in a group project for a sample of 112 BSW research seminar students at a large university in the Midwest. Students completed surveys on their experiences with the group project at the end of the semester. Multiple regression…
A Project Team: a Team or Just a Group?
Kateřina
2014-06-01
Full Text Available This paper deals with issues related to work in either teams or groups. The theoretical part discusses a team and a group with regards to its definition, classification and basic distinction, brings in more on the typology of team roles, personality assessment and sociometric methods. The analytical part tests the project (work team of a medical center represented in terms of personality and motivational types, team roles and interpersonal team relations concerning the willingness of cooperation and communication. The main objective of this work is to verify the validity of the assumptions that the analyzed team represents a very disparate group as for its composition from the perspective of personality types, types of motivation, team roles and interpersonal relations in terms of the willingness of cooperation and communication. A separate output shall focus on sociometric investigation of those team members where willingness to work together and communicate is based on the authors’ assumption of tight interdependence.
A Project Team: A Team or Just a Group?
Katerina Hrazdilova Bockova
2013-11-01
Full Text Available This paper deals with issues related to work in either teams or groups. The theoretical part which discusses a team and a group with regards to its definition, classification and basic distinction brings in more on the typology of team roles, personality assessment and sociometric methods. The analytical part tests the project (work team of a medical center represented in terms of personality and motivational types, team roles and interpersonal team relations concerning the willingness of cooperation and communication. The main objective of this work was to determine whether the existing team is not by its nature rather a working group that contributes to the generally perceived stagnation of that field.
Groner, Peter
2016-06-01
ERHAM has been used to analyze rotational spectra of many molecules with torsional splitting caused by one or two internal rotors. The gauche form of dimethyl ether-d1 whose equilibrium structure has C1 symmetry is an example of a molecule for which ERHAM could not model additional small splittings resolvable for many transitions, whereas the spectrum of the symmetric (anti, trans) form with a C{_s} equilibrium structure could be analyzed successfully with ERHAM. A more recent example where ERHAM failed is pinacolone CH_3-CO-C(CH_3)_3. In this case, the barriers to internal rotation of the methyl groups within the -C(CH_3)_3 unit are too high to produce observable internal rotation splittings, but the splittings due to the CH_3-CO methyl group could not be modeled correctly with ERHAM nor with any other available program (XIAM, BELGI-Cs, BELGI-C1, RAM36). In the paper, it was speculated that BELGI-Cs-2tops might be able to the job, but arguments against this possibility have also been put forward. The correlation between irreducible representations of groups and their subgroups according to Watson can be used not only to determine the total number of substates (components) to be expected but also to help decide which particular program has a chance for a successful analysis. As it turns out, the number of components of split lines depends on the molecular symmetry at equilibrium in relation to the highest possible symmetry for a given molecular symmetry group. Therefore, for pinacolone, the vibrational ground state is split into 10 torsional substates. P. Groner, J. Mol. Spectrosc. 278 (2012) 52-67. C. Richard et al. A&A 552 (2013), A117. Y. Zhao et al., J. Mol. Spectrosc. 318 (2015) 91-100, with references to all other programs mentioned in the abstract. J. K. G. Watson, Can. J. Physics 43 (1965) 1996-2007.
2012-02-23
... Fulbright-Hays Group Projects Abroad (GPA) Program supports overseas projects in training, research, and... grant application for the Fulbright- Hays GPA Programs at http://Grants.gov. You must search for the... Applications for New Awards; Fulbright-Hays Group Projects Abroad Program--Short-Term Projects and...
Group theory and its applications
Thapa, Ram Kumar
2019-01-01
Every molecule possesses symmetry and hence has symmetry operations and symmetry elements. From symmetry properties of a system we can deduce its significant physical results. Consequently it is essential to operations of a system forms a group. Group theory is an abstract mathematical tool that underlies the study of symmetry and invariance. By using the concepts of symmetry and group theory, it is possible to obtain the members of complete set of known basis functions of the various irreducible representations of the group. I practice this is achieved by applying the projection operators to linear combinations of atomic orbital (LCAO) when the valence electrons are tightly bound to the ions, to orthogonalized plane waves (OPW) when valence electrons are nearly free and to the other given functions that are judged to the particular system under consideration. In solid state physics the group theory is indispensable in the context of finding the energy bands of electrons in solids. Group theory can be applied...
Technology Applications Group Multimedia CD-ROM Project
McRacken, Kristi D.
1995-01-01
To produce a multimedia CD-ROM for the Technology Applications Group which would present the Technology Opportunity Showcase (TOPS) exhibits and Small Business Innovative Research (SBIR) projects to interested companies. The CD-ROM format is being used and developed especially for those companies who do not have Internet access, and cannot directly visit Langley through the World Wide Web. The CD-ROM will include text, pictures, sound, and movies. The information for the CD-ROM will be stored in a database from which the users can query and browse the information, and future CD's can be maintained and updated.
Nucci, M. C.
2016-09-01
We review some of our recent work devoted to the problem of quantization with preservation of Noether symmetries, finding hidden linearity in superintegrable systems, and showing that nonlocal symmetries are in fact local. In particular, we derive the Schrödinger equation for the isochronous Calogero goldfish model using its relation to Darwin equation. We prove the linearity of a classical superintegrable system on a plane of nonconstant curvature. We find the Lie point symmetries that correspond to the nonlocal symmetries (also reinterpreted as λ-symmetries) of the Riccati chain.
Nicolis, Alberto
2011-01-01
For relativistic quantum field theories, we consider Lorentz breaking, spatially homogeneous field configurations or states that evolve in time along a symmetry direction. We dub this situation "spontaneous symmetry probing" (SSP). We mainly focus on internal symmetries, i.e. on symmetries that commute with the Poincare group. We prove that the fluctuations around SSP states have a Lagrangian that is explicitly time independent, and we provide the field space parameterization that makes this manifest. We show that there is always a gapless Goldstone excitation that perturbs the system in the direction of motion in field space. Perhaps more interestingly, we show that if such a direction is part of a non-Abelian group of symmetries, the Goldstone bosons associated with spontaneously broken generators that do not commute with the SSP one acquire a gap, proportional to the SSP state's "speed". We outline possible applications of this formalism to inflationary cosmology.
Hamhalter, Jan; Turilova, Ekaterina
2017-02-01
Quantum symmetries of spectral lattices are studied. Basic properties of spectral order on A W ∗-algebras are summarized. Connection between projection and spectral automorphisms is clarified by showing that, under mild conditions, any spectral automorphism is a composition of function calculus and Jordan ∗-automorphism. Complete description of quantum spectral symmetries on Type I and Type II A W ∗-factors are completely described.
Democratic elements in group and project organized PBL
Qvist, Palle
2006-01-01
Students in a democratic learning system as the Aalborg Model knows of and uses democratics skills as e.g. the ability to discuss and accept other points of view, negotiate, compromise, reach consensus or accept the result of a vote in striving to reach specific common or personal learning goals,...... that students make decisions related to learning and learning goals, learning processes and behaviour after discussions and so called rounds which indicates hat they develop democratic skill useful in social relations....... learning system. It contrasts it to an authoritarian or elitist systems. Then it brings the results from an investigation of 9 process analyses’ written at the end of the second semester 2005 by project groups from The Technical Natural Scientific Basic Year at Aalborg University and concludes...
Steam Generator Group Project. Task 6. Channel head decontamination
Allen, R.P.; Clark, R.L.; Reece, W.D.
1984-08-01
The Steam Generator Group Project utilizes a retired-from-service pressurized-water-reactor steam generator as a test bed and source of specimens for research. An important preparatory step to primary side research activities was reduction of the radiation field in the steam generator channel head. This task report describes the channel head decontamination activities. Though not a programmatic research objective it was judged beneficial to explore the use of dilute reagent chemical decontamination techniques. These techniques presented potential for reduced personnel exposure and reduced secondary radwaste generation, over currently used abrasive blasting techniques. Two techniques with extensive laboratory research and vendors prepared to offer commercial application were tested, one on either side of the channel head. As indicated in the report, both techniques accomplished similar decontamination objectives. Neither technique damaged the generator channel head or tubing materials, as applied. This report provides details of the decontamination operations. Application system and operating conditions are described.
Loebbert, Florian
2016-01-01
In these introductory lectures we discuss the topic of Yangian symmetry from various perspectives. Forming the classical counterpart of the Yangian and an extension of ordinary Noether symmetries, first the concept of nonlocal charges in classical, two-dimensional field theory is reviewed. We then define the Yangian algebra following Drinfeld's original motivation to construct solutions to the quantum Yang-Baxter equation. Different realizations of the Yangian and its mathematical role as a Hopf algebra and quantum group are discussed. We demonstrate how the Yangian algebra is implemented in quantum, two-dimensional field theories and how its generators are renormalized. Implications of Yangian symmetry on the two-dimensional scattering matrix are investigated. We furthermore consider the important case of discrete Yangian symmetry realized on integrable spin chains. Finally we give a brief introduction to Yangian symmetry in planar, four-dimensional super Yang-Mills theory and indicate its impact on the dila...
Blum, Alexander Simon
2009-06-10
This thesis deals with the possibility of describing the flavor sector of the Standard Model of Particle Physics (with neutrino masses), that is the fermion masses and mixing matrices, with a discrete, non-abelian flavor symmetry. In particular, mass independent textures are considered, where one or several of the mixing angles are determined by group theory alone and are independent of the fermion masses. To this end a systematic analysis of a large class of discrete symmetries, the dihedral groups, is analyzed. Mass independent textures originating from such symmetries are described and it is shown that such structures arise naturally from the minimization of scalar potentials, where the scalars are gauge singlet flavons transforming non-trivially only under the flavor group. Two models are constructed from this input, one describing leptons, based on the group D{sub 4}, the other describing quarks and employing the symmetry D{sub 14}. In the latter model it is the quark mixing matrix element V{sub ud} - basically the Cabibbo angle - which is at leading order predicted from group theory. Finally, discrete flavor groups are discussed as subgroups of a continuous gauge symmetry and it is shown that this implies that the original gauge symmetry is broken by fairly large representations. (orig.)
Nomoto, Takuya; Ikeda, Hiroaki
2017-02-01
We present the group-theoretical classification of gap functions in superconductors coexisting with some magnetic order in non-symmorphic magnetic space groups. On the basis of the weak-coupling BCS theory, we show that UCoGe-type ferromagnetic superconductors must have horizontal line nodes on either the kz = 0 or ±π/c plane. Moreover, it is likely that additional Weyl point nodes exist at the axial point. On the other hand, in UPd2Al3-type antiferromagnetic superconductors, gap functions with Ag symmetry possess horizontal line nodes in the antiferromagnetic Brillouin zone boundary perpendicular to the c-axis. In other words, the conventional fully gapped s-wave superconductivity is forbidden in this type of antiferromagnetic superconductor, regardless of the pairing mechanism, as long as the Fermi surface crosses a zone boundary. UCoGe and UPd2Al3 are candidate unconventional superconductors possessing hidden symmetry-protected line nodes, peculiar to non-symmorphic magnetic space groups.
Discussion as media and tool in PBL project-groups
Spliid, Claus Monrad
2013-01-01
The Aalborg PBL Model encourages project-management as a way for students to achieve efficiency and effectiveness in their study-projects. This paper looks into how the development of conversation skills relates to project-management as well as other factors. Through analysis of interviews focusing...
75 FR 59049 - International Education Programs Service; Fulbright-Hays Group Projects Abroad Program
2010-09-24
... the Fulbright-Hays Group Projects Abroad (GPA) Program administered by the International Education... Education Fulbright-Hays Group Projects Abroad Program; Notices #0;#0;Federal Register / Vol. 75 , No. 185... Service; Fulbright-Hays Group Projects Abroad Program AGENCY: Office of Postsecondary...
Lovelady, Benjamin C
2015-01-01
According to the Coleman-Mandula theorem, any gauge theory of gravity combined with an internal symmetry based on a Lie group must take the form of a direct product in order to be consistent with basic assumptions of quantum field theory. However, we show that an alternative gauging of a simple group can lead dynamically to a spacetime with compact internal symmetry. The biconformal gauging of the conformal symmetry of n-dim Euclidean space doubles the dimension to give a symplectic manifold. Examining one of the Lagrangian submanifolds in the flat case, we find that in addition to the expected SO(n) connection and curvature, the solder form necessarily becomes Lorentzian. General coordinate invariance gives rise to an SO(n-1,1) connection on the spacetime. The principal fiber bundle character of the original SO(n) guarantees that the two symmetries enter as a direct product, in agreement with the Coleman-Mandula theorem.
Lovelady, Benjamin C.; Wheeler, James T.
2016-04-01
According to the Coleman-Mandula theorem, any gauge theory of gravity combined with an internal symmetry based on a Lie group must take the form of a direct product in order to be consistent with basic assumptions of quantum field theory. However, we show that an alternative gauging of a simple group can lead dynamically to a spacetime with compact internal symmetry. The biconformal gauging of the conformal symmetry of n-dimensional Euclidean space doubles the dimension to give a symplectic manifold. Examining one of the Lagrangian submanifolds in the flat case, we find that in addition to the expected S O (n ) connection and curvature, the solder form necessarily becomes Lorentzian. General coordinate invariance gives rise to an S O (n -1 ,1 ) connection on the spacetime. The principal fiber bundle character of the original S O (n ) guarantees that the two symmetries enter as a direct product, in agreement with the Coleman-Mandula theorem.
Vladan Nikolić
2015-02-01
Full Text Available The idea of construction of twin buildings is as old as architecture itself, and yet there is hardly any study emphasizing their specificity. Most frequently there are two objects or elements in an architectural composition of “twins” in which there may be various symmetry relations, mostly bilateral symmetries. The classification of “twins” symmetry in this paper is based on the existence of bilateral symmetry, in terms of the perception of an observer. The classification includes both, 2D and 3D perception analyses. We start analyzing a pair of twin buildings with projection of the architectural composition elements in 2D picture plane (plane of the composition and we distinguish four 2D keyframe cases based on the relation between the bilateral symmetry of the twin composition and the bilateral symmetry of each element. In 3D perception for each 2D keyframe case there are two sub-variants, with and without a symmetry plane parallel to the picture plane. The bilateral symmetry is dominant if the corresponding symmetry plane is orthogonal to the picture plane. The essence of the complete classification is relation between the bilateral (dominant symmetry of the architectural composition and the bilateral symmetry of each element of that composition.
An integrative framework for managing project issues across stakeholder groups
van Offenbeek, Marjolein A.G.; Vos, Janita F.J.
2016-01-01
The stakeholders and the issues associated with a project are different concepts but closely interconnected. Despite this, the project stakeholder management literature falls short in analyzing the linkages between the stakeholders and the issues they bring. This paper develops a multilayered
An integrative framework for managing project issues across stakeholder groups
van Offenbeek, Marjolein A.G.; Vos, Janita F.J.
2016-01-01
The stakeholders and the issues associated with a project are different concepts but closely interconnected. Despite this, the project stakeholder management literature falls short in analyzing the linkages between the stakeholders and the issues they bring. This paper develops a multilayered stakeh
Transmedia Teaching Framework: From Group Projects to Curriculum Development
Reid, James; Gilardi, Filippo
2016-01-01
This paper describes an innovative project-based learning framework theoretically based on the ideas of Transmedia Storytelling, Participatory Cultures and Multiple intelligences that can be integrated into the f?lipped classroom method, and practically addressed using Content- Based Instruction (CBI) and Project-Based Learning (PBL) approaches.…
Smart Video Communication for Social Groups - The Vconect Project
Ursu, M.; Stollenmayer, P.; Williams, D.; Torres, P.; Cesar Garcia, P.S.; Farber, N.; Geelhoed, E.
2014-01-01
This article introduces the Vconect project. Vconect (Video Communications for Networked Communities) is a collaborative European research and development project dealing with high-quality enriched video as a medium for mass communication within social communities. The technical capabilities where V
Skala, L.; Jungwirth, P.
1989-10-01
A group symmetry analysis of the Pauli master equation for the excitation energy transfer in the cyclic arrangement of N ( N= 6- 36) antenna Bchl molecules surrounding the bacterial reaction center of Rhodopseudomonas viridis is performed. The group theory allows to find analytic expressions for the most important observables (the antenna and reaction center fluorescence intensities and the quantum yield of the transfer to the charge transfer state) and to express their dependence on N. The time dependence of the fluorescence intensities is given by two exponentials, however, a single-exponential approximation can be used for t> t0 = 4-25 ps. The quantum yield of the excitation energy transfer to the reaction center charge transfer state is high (0.71- 0.98) for the whole range of physically acceptable values of the Förster radius R0 = 46-96 Å.
Voisin, Claire
1999-01-01
This is the English translation of Professor Voisin's book reflecting the discovery of the mirror symmetry phenomenon. The first chapter is devoted to the geometry of Calabi-Yau manifolds, and the second describes, as motivation, the ideas from quantum field theory that led to the discovery of mirror symmetry. The other chapters deal with more specialized aspects of the subject: the work of Candelas, de la Ossa, Greene, and Parkes, based on the fact that under the mirror symmetry hypothesis, the variation of Hodge structure of a Calabi-Yau threefold determines the Gromov-Witten invariants of its mirror; Batyrev's construction, which exhibits the mirror symmetry phenomenon between hypersurfaces of toric Fano varieties, after a combinatorial classification of the latter; the mathematical construction of the Gromov-Witten potential, and the proof of its crucial property (that it satisfies the WDVV equation), which makes it possible to construct a flat connection underlying a variation of Hodge structure in the ...
Häring, Reto Andreas
1993-01-01
The representations of the observable algebra of a low dimensional quantum field theory form the objects of a braided tensor category. The search for gauge symmetry in the theory amounts to finding an algebra which has the same representation category. In this paper we try to establish that every quantum field theory satisfying some basic axioms posseses a weak quasi Hopf algebra as gauge symmetry. The first step is to construct a functor from the representation category to the category of finite dimensional vector spaces. Given such a functor we can use a generalized reconstruction theorem to find the symmetry algebra. It is shown how this symmetry algebra is used to build a gauge covariant field algebra and we investigate the question why this generality is necessary.
Symmetry rules How science and nature are founded on symmetry
Rosen, Joe
2008-01-01
When we use science to describe and understand the world around us, we are in essence grasping nature through symmetry. In fact, modern theoretical physics suggests that symmetry is a, if not the, foundational principle of nature. Emphasizing the concepts, this book leads the reader coherently and comprehensively into the fertile field of symmetry and its applications. Among the most important applications considered are the fundamental forces of nature and the Universe. It is shown that the Universe cannot possess exact symmetry, which is a principle of fundamental significance. Curie's principle - which states that the symmetry of the effect is at least that of the cause - features prominently. An introduction to group theory, the mathematical language of symmetry, is included. This book will convince all interested readers of the importance of symmetry in science. Furthermore, it will serve as valuable background reading for all students in the physical sciences.
Notes on generalized global symmetries in QFT
Sharpe, E
2015-01-01
It was recently argued that quantum field theories possess one-form and higher-form symmetries, labelled `generalized global symmetries.' In this paper, we describe how those higher-form symmetries can be understood mathematically as special cases of more general 2-groups and higher groups, and discuss examples of quantum field theories admitting actions of more general higher groups than merely one-form and higher-form symmetries. We discuss analogues of topological defects for some of these higher symmetry groups, relating some of them to ordinary topological defects. We also discuss topological defects in cases in which the moduli `space' (technically, a stack) admits an action of a higher symmetry group. Finally, we outline a proposal for how certain anomalies might potentially be understood as describing a transmutation of an ordinary group symmetry of the classical theory into a 2-group or higher group symmetry of the quantum theory, which we link to WZW models and bosonization.
From groups to geometry and back
Climenhaga, Vaughn
2017-01-01
Groups arise naturally as symmetries of geometric objects, and so groups can be used to understand geometry and topology. Conversely, one can study abstract groups by using geometric techniques and ultimately by treating groups themselves as geometric objects. This book explores these connections between group theory and geometry, introducing some of the main ideas of transformation groups, algebraic topology, and geometric group theory. The first half of the book introduces basic notions of group theory and studies symmetry groups in various geometries, including Euclidean, projective, and hyperbolic. The classification of Euclidean isometries leads to results on regular polyhedra and polytopes; the study of symmetry groups using matrices leads to Lie groups and Lie algebras. The second half of the book explores ideas from algebraic topology and geometric group theory. The fundamental group appears as yet another group associated to a geometric object and turns out to be a symmetry group using covering space...
China’s Hongqi Group Invests 500 Million Yuan in Guixi Copper Processing Project
2008-01-01
<正>China’s Hongqi Group recently signed an agreement with Guixi municipality to invest 500 million yuan in developing the copper processing project in Guixi.It is reported that this is the seveth copper processing project with
Mir-Kasimov, R. M.
1997-03-01
The Quantum Field Theory (QFT) is considered in which momenta belong to the space of constant nonzero curvature. The conjugated configurational space is quantized space. It is connected with the momentum space by the Fourier expansion in matrix elements of the group of motions of this space. The generators of the translations in the configurational space are differential - difference operators and can be considered as the generators of the q- deformations of the Poincaré group. The deformed character of the translations leads to radical modification of the singularities of the field - theoretical functions. As a result, the S - matrix elements do not contain the non-integrable expressions.
Yunnan Smelting Group Examines an Aluminum Project for Possible Investment
2008-01-01
<正>Tian Yong,General Manager of Yunnan Smelt- ing Group,has gone to Zha gai NuoEr in Heilongjiang Province with a study group to conduct a full careful examination on the feasi- bility of the investment in the aluminum pro- ject.Yunnan Smelting Group is a large-scale
Computer-Mediated Collaborative Projects: Processes for Enhancing Group Development
Dupin-Bryant, Pamela A.
2008-01-01
Groups are a fundamental part of the business world. Yet, as companies continue to expand internationally, a major challenge lies in promoting effective communication among employees who work in varying time zones. Global expansion often requires group collaboration through computer systems. Computer-mediated groups lead to different communicative…
Zhou, Chunfang; Valero, Paola
2015-01-01
Different pedagogical strategies influence the development of creativity in project groups in science and engineering education. This study is a comparison between two cases: Problem-Based Learning (PBL) in Denmark and Project-Organized Learning (POL) in China.......Different pedagogical strategies influence the development of creativity in project groups in science and engineering education. This study is a comparison between two cases: Problem-Based Learning (PBL) in Denmark and Project-Organized Learning (POL) in China....
Matveev, Vladimir S.
2016-01-01
The paper is grown from the lecture course "Metric projective geometry" which I hold at the summer school "Finsler geometry with applications" at Karlovassi, Samos, in 2014, and at the workshop before the 8th seminar on Geometry and Topology of the Iranian Mathematical society at the Amirkabir University of Technology in 2015. The goal of this lecture course was to show how effective projectively invariant objects can be used to solve natural and named problems in differential geometry, and t...
Givental graphs and inversion symmetry
Dunin-Barkowski, P; Spitz, L
2012-01-01
Inversion symmetry is a very non-trivial discrete symmetry of Frobenius manifolds. It was obtained by Dubrovin from one of the elementary Schlesinger transformations of a special ODE associated to Frobenius manifold. In this paper, we review the Givental group action on Frobenius manifolds in terms of Feynman graphs and then we obtain an interpretation of the inversion symmetry in terms of the action of the Givental group. We also consider the implication of this interpretation of the inversion symmetry for the Schlesinger transformations and for the Hamiltonians of the associated principle hierarchy.
Hasselstroem, J.; Karis, O.; Weinelt, M. [Uppsala Univ. (Sweden)] [and others
1997-04-01
When a molecule is adsorbed on a metal surface by chemical bonding new electronic states are formed. For noble and transition metals these adsorption-induced states overlap with the much more intense metal d-valence band, making them difficult to probe by for instance direct photoemission. However, it has recently been shown that X-ray emission spectroscopy (XES) can be applied to adsorbate systems. Since the intermediate state involves a core hole, this technique has the power to project out the partial density of states around each atomic site. Both the excitation and deexcitation processes are in general governed by the dipole selection rules. For oriented system, it is hence possible to obtain a complete separation into 2p{sub x}, 2p{sub y} and 2p{sub z} contributions using angular resolved measurements. The authors have applied XES together with other core level spectroscopies to glycine adsorption on Cu(110). Glycine (NH{sub 2}CH{sub 2}COOH) is the smallest amino acid and very suitable to study by core level spectroscopy since it has several functional groups, all well separated in energy by chemical shifts. Its properties are futhermore of biological interest. In summary, the authors have shown that it is possible to apply XES to more complicated molecular adsorbates. The assignment of different electronic states is however not as straight forward as for simple diatomic molecules. For a complete understanding of the redistribution and formation of new electronic states associated with the surface chemical bond, experimental data must be compared to theoretical calculations.
2+1-Gravity and The Embedding its Dynamical Symmetry and Para-Supersymmetry into SO(4,c) Group
Jafarizadeh, M A; Moayedi, S K
1999-01-01
Some special solutions of the Einstein-Maxwell action with a non-negative cosmological constant and a very heavy point mass particle have been obtained. The solutions correspond to static spacetime of locally constant curvature in its spatial part and a constant magnetic field of a magnetic monopole together with deficit of angle at the location of point mass. The quantum mechanics of a point particle in these spacetimes in the absence of angular deficit has been solved algebraically both relativistically and non-relativistically. It has been also shown that these 2-dimensional Hamiltonians have the degeneracy group of GL(2,c) type and para-supersymmetry of arbitrary order or shape invariance, which is originated from a SO(4,c) group.
Haghshenas, R; Langari, A; Rezakhani, A T
2014-11-12
We study different phases of the one-dimensional bond-alternating spin-1/2 Heisenberg model by using the symmetry fractionalization mechanism. We employ the infinite matrix-product state representation of the ground state (through the infinite-size density matrix renormalization group algorithm) to obtain inequivalent projective representations and commutation relations of the (unbroken) symmetry groups of the model, which are used to identify the different phases. We find that the model exhibits trivial as well as symmetry-protected topological phases. The symmetry-protected topological phases are Haldane phases on even/odd bonds, which are protected by the time-reversal (acting on the spin as σ → -σ), parity (permutation of the chain about a specific bond), and dihedral (π-rotations about a pair of orthogonal axes) symmetries. Additionally, we investigate the phases of the most general two-body bond-alternating spin-1/2 model, which respects the time-reversal, parity, and dihedral symmetries, and obtain its corresponding twelve different types of the symmetry-protected topological phases.
Configuring Web-based Media for Communication in Dispersed Project Groups
Scheepers, Rens; Nicolajsen, Hanne Westh
2006-01-01
meetings, telephone) are not always viable options. Instead, computer-based communication media such as email, project intranets and extranets become surrogate conduits for day-to-day project communication and exchange of project-related content. We examined the effect of different media configurations......We studied how project groups in a pharmaceutical organization communicate project content. The project groups are geographically dispersed, and operate in different time zones. In such project environments, synchronous or geographically bounded modes of communication channels (e.g., face to face...... on the nature of content created by the project groups. We found that configuration decisions, notably the responsibility for content provision and who had access to content, influenced medium choice and the nature of communication taking place via the medium. More substantive content resulted when content...
Helping Students Understand the Role of Symmetry in Chemistry Using the Particle-in-a-Box Model
Manae, Meghna A.; Hazra, Anirban
2016-01-01
In a course on chemical applications of symmetry and group theory, students learn to use several useful tools (like character tables, projection operators, and correlation tables), but in the process of learning the mathematical details, they often miss the conceptual big picture about "why" and "how" symmetry leads to the…
Interest groups, the Lesotho Highlands Water Project Phase 1 and ...
attempts to influence public policy and their representation ... concept 'interest group', while in the third I investigate inter- ... groups will play certain roles within this arena and articulate ... Formally organised; have other social functions; part of a governmental ..... social problems that are likely to occur during Phase 1B and.
Horizontal Symmetry: Bottom Up and Top Down
Lam, C S
2011-01-01
A group-theoretical connection between horizontal symmetry $\\G$ and fermion mixing is established, and applied to neutrino mixing. The group-theoretical approach is consistent with a dynamical theory based on $U(1)\\times \\G$, but the dynamical theory can be used to pick out the most stable mixing that purely group-theoretical considerations cannot. A symmetry common to leptons and quarks is also discussed. This higher symmetry picks $A_4$ over $S_4$ to be the preferred symmetry for leptons.
Attanucci, Frank J.; Losse, John
2008-01-01
In a first calculus course, it is not unusual for students to encounter the theorems which state: If f is an even (odd) differentiable function, then its derivative is odd (even). In our paper, we prove some theorems which show how the symmetry of a continuous function f with respect to (i) the vertical line: x = a or (ii) with respect to the…
A Project in Small-Group Decision Making.
Kolb, Judith A.
1999-01-01
In small groups, business students choose and demonstrate a decision-making technique appropriate for an organizational situation they develop. Performance is evaluated by peers on the basis of situation choice, demonstration of technique, and quality of the solution. (SK)
Jinchuan Group Breaks Ground for a 300,000-ton Copper Deep Processing Project
2012-01-01
<正>According to Jinchang Municipal Government of Gansu,on August 21,Jinchuan Group broke ground for its 400,000-ton ionic membrane caustic soda project,300,000-ton PVC project,300,000-ton copper deep processing project,
New Opportunities for Women: A Group Entry Project at Newcastle Upon Tyne
Peacock, Geraldine; And Others
1978-01-01
The Newcastle project, "New Opportunities for Women," tests the feasibility of group admission for women who prefer to apply and study as a group at the Open University. Characteristics and achievement of 18 such women are described. (LBH)
A Poststructuralist View on Student’s Project Groups
Christensen, Gerd
2016-01-01
The aim of this paper is to demonstrate how poststructuralism and social constructionism can contribute to the empirical research on groups in problem-based learning (PBL). The paper outlines the analytical complexity and shows, through empirical examples, the potentials and limitations of this p...... no guidance for practice. Though both limitations raise serious problems for the practitioner, I intend to argue that the potentials of the analytical perspective are far more important than the challenges when it comes to social psychological research in groups in PBL...
SYMMETRY IN WORLD TRADE NETWORK
Hui WANG; Guangle YAN; Yanghua XIAO
2009-01-01
Symmetry of the world trade network provides a novel perspective to understand the world-wide trading system. However, symmetry in the world trade network (WTN) has been rarely studied so far. In this paper, the authors systematically explore the symmetry in WTN. The authors construct WTN in 2005 and explore the size and structure of its automorphism group, through which the authors find that WTN is symmetric, particularly, locally symmetric to a certain degree. Furthermore, the authors work out the symmetric motifs of WTN and investigate the structure and function of the symmetric motifs, coming to the conclusion that local symmetry will have great effect on the stability of the WTN and that continuous symmetry-breakings will generate complexity and diversity of the trade network. Finally, utilizing the local symmetry of the network, the authors work out the quotient of WTN, which is the structural skeleton dominating stability and evolution of WTN.
Symmetry of crystals and molecules
Ladd, Mark
2014-01-01
This book successfully combines a thorough treatment of molecular and crystalline symmetry with a simple and informal writing style. By means of familiar examples the author helps to provide the reader with those conceptual tools necessary for the development of a clear understanding of what are often regarded as 'difficult' topics. Christopher Hammond, University of Leeds This book should tell you everything you need to know about crystal and molecular symmetry. Ladd adopts an integrated approach so that the relationships between crystal symmetry, molecular symmetry and features of chemical interest are maintained and reinforced. The theoretical aspects of bonding and symmetry are also well represented, as are symmetry-dependent physical properties and the applications of group theory. The comprehensive coverage will make this book a valuable resource for a broad range of readers.
Legré, J.-P.; Albinet, G.; Firpo, J.-L.; Tremblay, A.-M. S.
1984-11-01
This paper is concerned with the liquid-expanded (LE) -liquid-condensed (LC) transition in monolayers of amphiphilic molecules at the air-water interface. A model, which can be mapped into the Blume-Emery-Griffiths Hamiltonian, has been considered before within the (mean-field) Bragg-Williams approximation and it gave results which could be successfully compared with experiment. The LE-LC transition has been associated with a chiral-symmetry breaking of the hydrocarbon-chain defects. This model is treated here with a Migdal-Kadanoff approximate position-space renormalization group. Renormalization-group flows are consistent with those obtained by previous authors. The connection between experimental and Hamiltonian parameters is easiest for a particular choice of ensemble, which turns out to be rather subtle for this problem. As in the work of Lavis, Southern, and Bell, isotherms in the surface-pressure-molecular-area plane do not show a signature of the LE-LC transition. The better agreement between experiments (showing a compressibility jump at the LE-LC transition) and mean-field theory suggests that in these cases long-range forces depending on the nature of the polar head and on the water substrate pH are responsible for the jump.
On m-ω1-pω+n-Projective Abelian p-Groups
Danchev Peter
2014-12-01
Full Text Available For any non-negative integers m and n, we define the classes of m-ω1-pω+n- projective groups and strongly m-ω1-pω+n-projective groups, which properly encompass the classes of ω1-pω+n-projectives introduced by Keef in J. Algebra Numb. Th. Acad. (2010 and strongly ω1-pω+n-projectives introduced by the present author in Hacettepe J. Math. Stat. (2014, respectively. The new group structures share many interesting properties, which are closely related to these of the aforementioned two own subclasses. Moreover, certain basic results in this direction are also established.
A New Group-Formation Method for Student Projects
Borges, Jose; Dias, Teresa Galvao; Cunha, Joao Falcao E.
2009-01-01
In BSc/MSc engineering programmes at Faculty of Engineering of the University of Porto (FEUP), the need to provide students with teamwork experiences close to a real world environment was identified as an important issue. A new group-formation method that aims to provide an enriching teamwork experience is proposed. Students are asked to answer a…
A Poststructuralist View on Student’s Project Groups
Christensen, Gerd
2016-01-01
The aim of this paper is to demonstrate how poststructuralism and social constructionism can contribute to the empirical research on groups in problem-based learning (PBL). The paper outlines the analytical complexity and shows, through empirical examples, the potentials and limitations of this p......The aim of this paper is to demonstrate how poststructuralism and social constructionism can contribute to the empirical research on groups in problem-based learning (PBL). The paper outlines the analytical complexity and shows, through empirical examples, the potentials and limitations...... of this perspective as an alternative to traditional group psychology. While the potentials of poststructuralism and social constructionism as an analytical complex seem to be the endeavor for relentless critique, the limitations are the ‘empty subject’ and the avoidance of any kind of normativity that leave...... no guidance for practice. Though both limitations raise serious problems for the practitioner, I intend to argue that the potentials of the analytical perspective are far more important than the challenges when it comes to social psychological research in groups in PBL...
A New Group-Formation Method for Student Projects
Borges, Jose; Dias, Teresa Galvao; Cunha, Joao Falcao E.
2009-01-01
In BSc/MSc engineering programmes at Faculty of Engineering of the University of Porto (FEUP), the need to provide students with teamwork experiences close to a real world environment was identified as an important issue. A new group-formation method that aims to provide an enriching teamwork experience is proposed. Students are asked to answer a…
A Poststructuralist View on Student's Project Groups: Possibilities and Limitations
Christensen, Gerd
2016-01-01
The aim of this paper is to demonstrate how poststructuralism and social constructionism can contribute to the empirical research on groups in problem-based learning (PBL). The paper outlines the analytical complexity and shows, through empirical examples, the potentials and limitations of this perspective as an alternative to traditional group…
A Poststructuralist View on Student's Project Groups: Possibilities and Limitations
Christensen, Gerd
2016-01-01
The aim of this paper is to demonstrate how poststructuralism and social constructionism can contribute to the empirical research on groups in problem-based learning (PBL). The paper outlines the analytical complexity and shows, through empirical examples, the potentials and limitations of this perspective as an alternative to traditional group…
The Role of Communication and Cohesion in Reducing Social Loafing in Group Projects
Lam, Chris
2015-01-01
This study examines previously untested variables that influence social loafing in professional and technical communication group projects by determining the influence of communication quality and task cohesion on social loafing. A set-up factors model, which included group size, peer review, project scope, and method of team formation, was also…
Social Loafing on Group Projects: Structural Antecedents and Effect on Student Satisfaction
Aggarwal, Praveen; O'Brien, Connie L.
2008-01-01
To respond to the expectations of the industry and business school accreditation bodies, marketing faculty have been making extensive use of group projects in their curricula. A common problem with the use of student groups, however, is that of social loafing. In this study, we identify some easy-to-implement project set-up factors and examine…
Romeu, Jorge Luis
2008-01-01
This article discusses our teaching approach in graduate level Engineering Statistics. It is based on the use of modern technology, learning groups, contextual projects, simulation models, and statistical and simulation software to entice student motivation. The use of technology to facilitate group projects and presentations, and to generate,…
600,000t/a High-Precision Aluminum Project of Yulian Group was Completed
2016-01-01
On January 11,Yulian Group 600,000t/a highprecision aluminum project was completed and launched into production,and entered production stage.It has been learned that,the production launching of this project signaled that Yulian Group became China’s first
Romeu, Jorge Luis
2008-01-01
This article discusses our teaching approach in graduate level Engineering Statistics. It is based on the use of modern technology, learning groups, contextual projects, simulation models, and statistical and simulation software to entice student motivation. The use of technology to facilitate group projects and presentations, and to generate,…
The Role of Communication and Cohesion in Reducing Social Loafing in Group Projects
Lam, Chris
2015-01-01
This study examines previously untested variables that influence social loafing in professional and technical communication group projects by determining the influence of communication quality and task cohesion on social loafing. A set-up factors model, which included group size, peer review, project scope, and method of team formation, was also…
Quantum entanglement and symmetry
Chruscinski, D; Kossakowski, A [Institute of Physics, Nicolaus Copernicus University, Grudziadzka 5/7, 87-100 Torun (Poland)
2007-11-15
One of the main problem in Quantum Information Theory is to test whether a given state of a composite quantum system is entangled or separable. It turns out that within a class of states invariant under the action of the symmetry group this problem considerably simplifies. We analyze multipartite invariant states and the corresponding symmetric quantum channels.
Quantum entanglement and symmetry
Chruściński, D.; Kossakowski, A.
2007-11-01
One of the main problem in Quantum Information Theory is to test whether a given state of a composite quantum system is entangled or separable. It turns out that within a class of states invariant under the action of the symmetry group this problem considerably simplifies. We analyze multipartite invariant states and the corresponding symmetric quantum channels.
Flavour from accidental symmetries
Ferretti, Luca [SISSA/ISAS and INFN, I-34013 Trieste (Italy); King, Stephen F. [School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Romanino, Andrea [SISSA/ISAS and INFN, I-34013 Trieste (Italy)
2006-11-15
We consider a new approach to fermion masses and mixings in which no special 'horizontal' dynamics is invoked to account for the hierarchical pattern of charged fermion masses and for the peculiar features of neutrino masses. The hierarchy follows from the vertical, family-independent structure of the model, in particular from the breaking pattern of the Pati-Salam group. The lightness of the first two fermion families can be related to two family symmetries emerging in this context as accidental symmetries.
Arzano, Michele; Kowalski-Glikman, Jerzy
2016-09-01
We construct discrete symmetry transformations for deformed relativistic kinematics based on group valued momenta. We focus on the specific example of κ-deformations of the Poincaré algebra with associated momenta living on (a sub-manifold of) de Sitter space. Our approach relies on the description of quantum states constructed from deformed kinematics and the observable charges associated with them. The results we present provide the first step towards the analysis of experimental bounds on the deformation parameter κ to be derived via precision measurements of discrete symmetries and CPT.
Linguistic Extension for Group Multicriteria Project Manager Selection
Javad Dodangeh
2014-01-01
Full Text Available Qualified human resource selection is one of the organizational key success factors. Since choosing the best candidate to fill the defined vacancy in a company is a complex task, intelligence analytical methods would be required to deal with this important issue. Regarding the vagueness and uncertainty of human resource selection process, it requires the linguistic extension of multicriteria decision making (MCDM models for robust recruitment. This research is aimed to develop a fuzzy MCDM model for linguistic reasoning under new fuzzy group decision making. The new linguistic reasoning for group decision making is able to aggregate subjective evaluation of the decision makers and hence create an opportunity to perform more robust human resource selection procedures. A numerical example demonstrates possibilities for the improvement of human resource management and any other business decision areas through applying the proposed model.
The focus group technique in electoral research - an experimental project
SANTOS NEVES, Manuela Lopes
2012-01-01
Full Text Available The article is about the application of focus group method in electoral research and its contribution to the strategic planning of campaigns. The methodological approach and analysis were based on the nature of information that this kind of research may provide. The starting point was an experimental research conducted by the campaign of a re-election candidate to the House of Representatives of the state of Espírito Santo.
Kirstin Peters
2010-11-01
Full Text Available A well-known result by Palamidessi tells us that πmix (the π-calculus with mixed choice is more expressive than πsep (its subset with only separate choice. The proof of this result argues with their different expressive power concerning leader election in symmetric networks. Later on, Gorla offered an arguably simpler proof that, instead of leader election in symmetric networks, employed the reducibility of incestual processes (mixed choices that include both enabled senders and receivers for the same channel when running two copies in parallel. In both proofs, the role of breaking (initial symmetries is more or less apparent. In this paper, we shed more light on this role by re-proving the above result - based on a proper formalization of what it means to break symmetries without referring to another layer of the distinguishing problem domain of leader election. Both Palamidessi and Gorla rephrased their results by stating that there is no uniform and reasonable encoding from πmix into πsep. We indicate how the respective proofs can be adapted and exhibit the consequences of varying notions of uniformity and reasonableness. In each case, the ability to break initial symmetries turns out to be essential.
Loebbert, Florian
2016-08-01
In these introductory lectures we discuss the topic of Yangian symmetry from various perspectives. Forming the classical counterpart of the Yangian and an extension of ordinary Noether symmetries, first the concept of nonlocal charges in classical, two-dimensional field theory is reviewed. We then define the Yangian algebra following Drinfel’d's original motivation to construct solutions to the quantum Yang-Baxter equation. Different realizations of the Yangian and its mathematical role as a Hopf algebra and quantum group are discussed. We demonstrate how the Yangian algebra is implemented in quantum, two-dimensional field theories and how its generators are renormalized. Implications of Yangian symmetry on the two-dimensional scattering matrix are investigated. We furthermore consider the important case of discrete Yangian symmetry realized on integrable spin chains. Finally we give a brief introduction to Yangian symmetry in planar, four-dimensional super Yang-Mills theory and indicate its impact on the dilatation operator and tree-level scattering amplitudes. These lectures are illustrated by several examples, in particular the two-dimensional chiral Gross-Neveu model, the Heisenberg spin chain and { N }=4 superconformal Yang-Mills theory in four dimensions.
Weiss, Asia; Whiteley, Walter
2014-01-01
This book contains recent contributions to the fields of rigidity and symmetry with two primary focuses: to present the mathematically rigorous treatment of rigidity of structures, and to explore the interaction of geometry, algebra, and combinatorics. Overall, the book shows how researchers from diverse backgrounds explore connections among the various discrete structures with symmetry as the unifying theme. Contributions present recent trends and advances in discrete geometry, particularly in the theory of polytopes. The rapid development of abstract polytope theory has resulted in a rich theory featuring an attractive interplay of methods and tools from discrete geometry, group theory, classical geometry, hyperbolic geometry and topology. The volume will also be a valuable source as an introduction to the ideas of both combinatorial and geometric rigidity theory and its applications, incorporating the surprising impact of symmetry. It will appeal to students at both the advanced undergraduate and gradu...
Binary Tetrahedral Flavor Symmetry
Eby, David A
2013-01-01
A study of the T' Model and its variants utilizing Binary Tetrahedral Flavor Symmetry. We begin with a description of the historical context and motivations for this theory, together with some conceptual background for added clarity, and an account of our theory's inception in previous works. Our model endeavors to bridge two categories of particles, leptons and quarks, a unification made possible by the inclusion of additional Higgs particles, shared between the two fermion sectors and creating a single coherent system. This is achieved through the use of the Binary Tetrahedral symmetry group and an investigation of the Tribimaximal symmetry evidenced by neutrinos. Our work details perturbations and extensions of this T' Model as we apply our framework to neutrino mixing, quark mixing, unification, and dark matter. Where possible, we evaluate model predictions against experimental results and find excellent matching with the atmospheric and reactor neutrino mixing angles, an accurate prediction of the Cabibb...
Symmetries of Ginsparg-Wilson Chiral Fermions
Mandula, Jeffrey E
2009-01-01
The group structure of the variant chiral symmetry discovered by Luscher in the Ginsparg-Wilson description of lattice chiral fermions is analyzed. It is shown that the group contains an infinite number of linearly independent symmetry generators, and the Lie algebra is given explicitly. CP is an automorphism of this extended chiral group, and the CP transformation properties of the symmetry generators are found. The group has an infinite-parameter subgroup, and the factor group whose elements are its cosets is isomorphic to the continuum chiral symmetry group. Features of the currents associated with these symmetries are discussed, including the fact that some different, non-commuting symmetry generators lead to the same Noether current. These are universal features of lattice chiral fermions based on the Ginsparg-Wilson relation; they occur in the overlap, domain-wall, and perfect-action formulations. In a solvable example - free overlap fermions - these non-canonical elements of lattice chiral symmetry are...
刘官厅; 范天佑
2003-01-01
The complex method of the plane elasticity in 2D quasicrystal with point group 10 mm tenfold rotational symmetry is established. First displacement potential function in the quasicrystal is represented by four analytic functions. Then by utilizing the properties of analytic function and through a great deal of derivation, the complex representations of stresses and displacements components of phonon fields and phason fields in the quasicrystal are given, which are the theoretical foundation for this method. From this theory, and by the help of conformal transformations in the theory of complex function, the problems of elliptic hole in the quasicrystal are solved. Its special cases are the solutions of well-known crack problem. Meanwhile, the results show that even if under the self-counterbalance force in the quasicrystal plane with elliptic hole, the stress components of phonon fields are also related to material constants of the quasicrystal when the phonon fields and phason fields are coupled, which is another distinctive difference from the properties of classical elastic theory. Besides, the present work is generalization and application of the complex method in the classical elastic theory established by Muskhelishvili to 2D quasicrystal. As in the classical elastic theory, if only conformal transformation from the quasicrystal plane to unit circle is found, any holey and crack problem in the quasicrystal plane could be solved.
Mei Symmetry and Noether Symmetry of the Relativistic Variable Mass System
FANG Jian-Hui
2004-01-01
The definition and criterion of the Mei symmetry of a relativistic variable mass system are given. The relation between the Mei symmetry and the Noether symmetry of the system is found under infinitesimal transformations of groups. The conserved quantities to which the Mei symmetry and Noether symmetry of the system lead are obtained.An example is given to illustrate the application of the result.
Discrete symmetries in the MSSM
Schieren, Roland
2010-12-02
The use of discrete symmetries, especially abelian ones, in physics beyond the standard model of particle physics is discussed. A method is developed how a general, abelian, discrete symmetry can be obtained via spontaneous symmetry breaking. In addition, anomalies are treated in the path integral approach with special attention to anomaly cancellation via the Green-Schwarz mechanism. All this is applied to the minimal supersymmetric standard model. A unique Z{sup R}{sub 4} symmetry is discovered which solves the {mu}-problem as well as problems with proton decay and allows to embed the standard model gauge group into a simple group, i.e. the Z{sup R}{sub 4} is compatible with grand unification. Also the flavor problem in the context of minimal flavor violation is addressed. Finally, a string theory model is presented which exhibits the mentioned Z{sup R}{sub 4} symmetry and other desirable features. (orig.)
Painlevé property, symmetries and symmetry reductions of the coupled Burgers system
Lian Zeng-Ju; Chen Li-Li; Lou Sen-Yue
2005-01-01
The Painlevé property, inverse recursion operator, infinite number of symmetries and Lie symmetry reductions of the coupled Burgers equation are given explicitly. Three sets of infinitely many symmetries of the considered model are obtained by acting the recursion operator and the inverse recursion operator on the trivial symmetries such as the identity transformation, the space translation and the scaling transformation respectively. These symmetries constitute an infinite dimensional Lie algebra while its finite dimensional Lie point symmetry subalgebra is used to find possible symmetry reductions and then the group invariant solutions.
Non-Crystallographic Symmetry in Packing Spaces
Valery G. Rau
2013-01-01
Full Text Available In the following, isomorphism of an arbitrary finite group of symmetry, non-crystallographic symmetry (quaternion groups, Pauli matrices groups, and other abstract subgroups, in addition to the permutation group, are considered. Application of finite groups of permutations to the packing space determines space tilings by policubes (polyominoes and forms a structure. Such an approach establishes the computer design of abstract groups of symmetry. Every finite discrete model of the real structure is an element of symmetry groups, including non-crystallographic ones. The set packing spaces of the same order N characterizes discrete deformation transformations of the structure.
Symmetry and quantum mechanics
Corry, Scott
2016-01-01
This book offers an introduction to quantum mechanics for professionals, students, and others in the field of mathematics who have a minimal background in physics with an understanding of linear algebra and group theory. It covers such topics as Lie groups, algebras and their representations, and analysis (Hilbert space, distributions, the spectral Theorem, and the Stone-Von Neumann Theorem). The book emphasizes the role of symmetry and is useful to physicists as it provides a mathematical introduction to the topic.
Symmetry Non-restoration at High Temperature
Rius, N
1998-01-01
We discuss the (non)-restoration of global and local symmetries at high temperature. First, we analyze a two-scalar model with $Z_2 \\times Z_2$ symmetry using the exact renormalization group. We conclude that inverse symmetry breaking is possible in this kind of models within the perturbative regime. Regarding local symmetries, we consider the $SU(2) \\otimes U(1)$ gauge symmetry and focus on the case of a strongly interacting scalar sector. Employing a model-independent chiral Lagrangian we find indications of symmetry restoration.
Westphal, Eduard; Gallardo, Hugo; Caramori, Giovanni Finoto; Sebastián, Nerea; Tamba, Maria-Gabriela; Eremin, Alexey; Kawauchi, Susumu; Prehm, Marko; Tschierske, Carsten
2016-06-01
Two isomeric achiral bent-core liquid crystals involving a 4-cyanoresorcinol core and containing a carbosilane unit as nanosegregating segment were synthesized and were shown to form ferroelectric liquid-crystalline phases. Inversion of the direction of one of the COO groups in these molecules leads to a distinct distribution of the electrostatic potential along the surface of the molecule and to a strong change of the molecular dipole moments. Thus, a distinct degree of segregation of the carbosilane units and consequent modification of the phase structure and coherence length of polar order result. For the compound with larger dipole moment (CN1) segregation of the carbosilane units is suppressed, and this compound forms paraelectric SmA and SmC phases; polar order is only achieved after transition to a new LC phase, namely, the ferroelectric leaning phase (SmCLs PS ) with the unique feature that tilt direction and polar direction coincide. The isomeric compound CN2 with a smaller dipole moment forms separate layers of the carbosilane groups and shows a randomized polar SmA phase (SmAPAR ) and ferroelectric polydomain SmCs PS phases with orthogonal combination of tilt and polar direction and much higher polarizations. Thus, surprisingly, the compound with the smaller molecular dipole moment shows increased polar order in the LC phases. Besides ferroelectricity, mirror-symmetry breaking with formation of a conglomerate of macroscopic chiral domains was observed in one of the SmC phases of CN1. These investigations contribute to the general understanding of the development of polar order and chirality in soft matter.
[Life project of a group of adolescents based on the theory of Paulo Freire].
Cardoso, Cristina Peres; Cocco, Maria Inês Monteiro
2003-01-01
This study aims to get to know the life project of a group of adolescents at a Basic Health Unit in Marilia-SP. A qualitative research was carried out through semi-structured interviews and group meetings, using the educational group technique with participant observation from the focus of Paulo Freire's theory. Throughout group discussions, three questions arose: what is being an adolescent; what is being healthy and what is the adolescent's life project. These themes were analyzed from the focus of Minayo. The analysis indicated that the adolescents have a life project, in spite of the characteristic difficulties of the socioeconomic conditions they belong to, a fact they perceive. The practice of Freire's ideals enhanced dialogue between the researcher and the group, pointing out that this is one way for a true critical reflection of the identified problems, providing adolescents with a means for making others aware and fighting for their life project.
Gauging without Initial Symmetry
Kotov, Alexei
2016-01-01
The gauge principle is at the heart of a good part of fundamental physics: Starting with a group G of so-called rigid symmetries of a functional defined over space-time Sigma, the original functional is extended appropriately by additional Lie(G)-valued 1-form gauge fields so as to lift the symmetry to Maps(Sigma,G). Physically relevant quantities are then to be obtained as the quotient of the solutions to the Euler-Lagrange equations by these gauge symmetries. In this article we show that one can construct a gauge theory for a standard sigma model in arbitrary space-time dimensions where the target metric is not invariant with respect to any rigid symmetry group, but satisfies a much weaker condition: It is sufficient to find a collection of vector fields v_a on the target M satisfying the extended Killing equation v_{a(i;j)}=0 for some connection acting on the index a. For regular foliations this is equivalent to merely requiring the distribution orthogonal to the leaves to be invariant with respect to leaf...
Marin MARINOV
2014-10-01
Full Text Available This paper introduces a special issue of the Journal Transport Problems on group research projects developed within the RailNewcastle summer school organised and held in Newcastle upon Tyne, North East England. The participants (both educators and students worked together in multinational and multidisciplinary groups to produce research projects. The topics of the group research projects were based around railway and logistics-related problems. As a result a collection of the best articles is produced for the purposes of this special issue.
Peters, Kirstin
2010-01-01
A well-known result by Palamidessi tells us that {\\pi}mix (the {\\pi}-calculus with mixed choice) is more expressive than {\\pi}sep (its subset with only separate choice). The proof of this result argues with their different expressive power concerning leader election in symmetric networks. Later on, Gorla of- fered an arguably simpler proof that, instead of leader election in symmetric networks, employed the reducibility of "incestual" processes (mixed choices that include both enabled senders and receivers for the same channel) when running two copies in parallel. In both proofs, the role of breaking (ini- tial) symmetries is more or less apparent. In this paper, we shed more light on this role by re-proving the above result-based on a proper formalization of what it means to break symmetries-without referring to another layer of the distinguishing problem domain of leader election. Both Palamidessi and Gorla rephrased their results by stating that there is no uniform and reason- able encoding from {\\pi}mix i...
Peters, Kirstin; 10.4204/EPTCS.41.10
2010-01-01
A well-known result by Palamidessi tells us that \\pimix (the \\pi-calculus with mixed choice) is more expressive than \\pisep (its subset with only separate choice). The proof of this result argues with their different expressive power concerning leader election in symmetric networks. Later on, Gorla offered an arguably simpler proof that, instead of leader election in symmetric networks, employed the reducibility of incestual processes (mixed choices that include both enabled senders and receivers for the same channel) when running two copies in parallel. In both proofs, the role of breaking (initial) symmetries is more or less apparent. In this paper, we shed more light on this role by re-proving the above result - based on a proper formalization of what it means to break symmetries without referring to another layer of the distinguishing problem domain of leader election. Both Palamidessi and Gorla rephrased their results by stating that there is no uniform and reasonable encoding from \\pimix into \\pisep. We...
How Do Students Define Their Roles and Responsibilities in Online Learning Group Projects?
Williams, Karen C.; Morgan, Kari; Cameron, Bruce A.
2011-01-01
The goal of this study was to explore the processes of group role formation in online class settings. Qualitative analysis was used to code chat logs and discussion threads in six undergraduate Family and Consumer Sciences online courses that required online group projects. Four themes related to the process of group role formation emerged:…
Symmetries in multi-Higgs-doublet models
Ivanov, I P
2012-01-01
We report the recent progress in understanding of symmetries which can be implemented in the scalar sector of electroweak symmetry breaking models with several Higgs doublets. In particular we present the list of finite reparametrization symmetry groups which can appear in the three-Higgs-doublet models.
Gauge origin of discrete flavor symmetries in heterotic orbifolds
Florian Beye
2014-09-01
Full Text Available We show that non-Abelian discrete symmetries in orbifold string models have a gauge origin. This can be understood when looking at the vicinity of a symmetry enhanced point in moduli space. At such an enhanced point, orbifold fixed points are characterized by an enhanced gauge symmetry. This gauge symmetry can be broken to a discrete subgroup by a nontrivial vacuum expectation value of the Kähler modulus T. Using this mechanism it is shown that the Δ(54 non-Abelian discrete symmetry group originates from a SU(3 gauge symmetry, whereas the D4 symmetry group is obtained from a SU(2 gauge symmetry.
Cornwell, J F
1989-01-01
Recent devopments, particularly in high-energy physics, have projected group theory and symmetry consideration into a central position in theoretical physics. These developments have taken physicists increasingly deeper into the fascinating world of pure mathematics. This work presents important mathematical developments of the last fifteen years in a form that is easy to comprehend and appreciate.
Choi, Youngsoo; Ro, Heejung
2012-01-01
The development of positive attitudes in team-based work is important in management education. This study investigates hospitality students' attitudes toward group projects by examining instructional factors and team problems. Specifically, we examine how the students' perceptions of project appropriateness, instructors' support, and evaluation…
Project-based learning in organizations : towards a methodology for learning in groups
Poell, R.F.; van der Krogt, F.J.
2003-01-01
This article introduces a methodology for employees in organizations to set up and carry out their own group learning projects. It is argued that employees can use project-based learning to make their everyday learning more systematic at times, without necessarily formalizing it. The article emphasi
Choi, Youngsoo; Ro, Heejung
2012-01-01
The development of positive attitudes in team-based work is important in management education. This study investigates hospitality students' attitudes toward group projects by examining instructional factors and team problems. Specifically, we examine how the students' perceptions of project appropriateness, instructors' support, and evaluation…
Project-based learning in organizations : towards a methodology for learning in groups
Poell, R.F.; van der Krogt, F.J.
2003-01-01
This article introduces a methodology for employees in organizations to set up and carry out their own group learning projects. It is argued that employees can use project-based learning to make their everyday learning more systematic at times, without necessarily formalizing it. The article
Secret Message Decryption: Group Consulting Projects Using Matrices and Linear Programming
Gurski, Katharine F.
2009-01-01
We describe two short group projects for finite mathematics students that incorporate matrices and linear programming into fictional consulting requests presented as a letter to the students. The students are required to use mathematics to decrypt secret messages in one project involving matrix multiplication and inversion. The second project…
Napa River Restoration Project: Oakville to Oak Knoll Reach, Group C Site 14
Information about the SFBWQP Napa River Restoration Project: Oakville to Oak Knoll Reach, Group C Site 14, part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquatic resources.
New Project in Huacheng Paper of Guangxi State Farms Sugar Group Laid the Foundation Stone
2010-01-01
@@ The foundation-stone laying ceremony of 200,000 t/y culture paper project in Huacheng Paper, a member of Guangxi State Farms Sugar Group, was held in Laibin, Guangxi Zhuang Autonomous Region, on October 18, 2009.
Homogeneous Operators and Projective Representations of the Möbius Group: A Survey
Bhaskar Bagchi; Gadadhar Misra
2001-11-01
This paper surveys the existing literature on homogeneous operators and their relationships with projective representations of $PSL(2, \\mathbb{R})$ and other Lie groups. It also includes a list of open problems in this area.
Symmetry of tetrahydroxycalix[4]arenes
M. GHORBANI
2006-10-01
Full Text Available Graph theory provides an elegant and natural representation of molecular symmetry and the resulting group expressed in terms of permutations is isomorphic to the permutation-inversion group of Longuet-Higgins. In this paper, using the group theory package GAP, the character table and the automorphism group of the Euclidean graph of tetrahydroxycalix[4]arenes were computed.
Grey Comprehensive Evaluation of Biomass Power Generation Project Based on Group Judgement
Xia, Huicong; Niu, Dongxiao
2017-06-01
The comprehensive evaluation of benefit is an important task needed to be carried out at all stages of biomass power generation projects. This paper proposed an improved grey comprehensive evaluation method based on triangle whiten function. To improve the objectivity of weight calculation result of only reference comparison judgment method, this paper introduced group judgment to the weighting process. In the process of grey comprehensive evaluation, this paper invited a number of experts to estimate the benefit level of projects, and optimized the basic estimations based on the minimum variance principle to improve the accuracy of evaluation result. Taking a biomass power generation project as an example, the grey comprehensive evaluation result showed that the benefit level of this project was good. This example demonstrates the feasibility of grey comprehensive evaluation method based on group judgment for benefit evaluation of biomass power generation project.
Group Creativity Development by Solving Real-life Project in Engineering Education
Zhou, Chunfang; Kolmos, Anette; Du, Xiangyun
2011-01-01
creativity can be developed by the mutual function of the four dimensions under the positive facilitation of supervisors. A case study was carried out with a student satellite project in the department of electronic systems at Aalborg University in Denmark. Multiple methods including interviews......In recent years, problem and project based learning (PBL) has been employed by a growing number of educational institutions to foster creative engineers. Among the diverse pedagogical practices of PBL, there has been an emergence of real-life project for students. Based on literature of creativity...... research, PBL theories and the social theory of learning, this paper analyzes and discusses four major dimensions of project work - problem analysis and solving, group learning, interdisciplinary learning and project management - as the factors in constructing creative learning environments. We think group...
Symmetries of Massive and Massless Neutrinos
Kim, Y S
2016-01-01
Wigner's little groups are subgroups of the Lorentz group dictating the internal space-time symmetries of massive and massless particles. These little groups are like O(3) and E(2) for massive and massless particles respectively. While the geometry of the O(3) symmetry is familiar to us, the geometry of the flat plane cannot explain the E(2)-like symmetry for massless particles. However, the geometry of a circular cylinder can explain the symmetry with the helicity and gauge degrees of freedom. It is shown further that the symmetry of the massless particle can be obtained as a zero-mass limit of O(3)-like symmetry for massive particles. It is shown further that the polarization of massless neutrinos is a consequence of gauge invariance, while the symmetry of massive neutrinos is still like O(3).
Symmetry constraints on many-body localization
Potter, Andrew C.; Vasseur, Romain
2016-12-01
We derive general constraints on the existence of many-body localized (MBL) phases in the presence of global symmetries, and show that MBL is not possible with symmetry groups that protect multiplets (e.g., all non-Abelian symmetry groups). Based on simple representation theoretic considerations, we derive general Mermin-Wagner-type principles governing the possible alternative fates of nonequilibrium dynamics in isolated, strongly disordered quantum systems. Our results rule out the existence of MBL symmetry-protected topological phases with non-Abelian symmetry groups, as well as time-reversal symmetry-protected electronic topological insulators, and in fact all fermion topological insulators and superconductors in the 10-fold way classification. Moreover, extending our arguments to systems with intrinsic topological order, we rule out MBL phases with non-Abelian anyons as well as certain classes of symmetry-enriched topological orders.
张素英; 邓子辰
2004-01-01
For the constrained generalized Hamiltonian system with dissipation, by introducing Lagrange multiplier and using projection technique, the Lie group integration method was presented, which can preserve the inherent structure of dynamic system and the constraint-invariant. Firstly, the constrained generalized Hamiltonian system with dissipative was converted to the non-constraint generalized Hamiltonian system, then Lie group integration algorithm for the non-constraint generalized Hamiltonian system was discussed, finally the projection method for generalized Hamiltonian system with constraint was given. It is found that the constraint invariant is ensured by projection technique, and after introducing Lagrange multiplier the Lie group character of the dynamic system can't be destroyed while projecting to the constraint manifold. The discussion is restricted to the case of holonomic constraint. A presented numerical example shows the effectiveness of the method.
Mixed symmetry tensors in the worldline formalism
Corradini, Olindo; Edwards, James P.
2016-05-01
We consider the first quantised approach to quantum field theory coupled to a non-Abelian gauge field. Representing the colour degrees of freedom with a single family of auxiliary variables the matter field transforms in a reducible representation of the gauge group which — by adding a suitable Chern-Simons term to the particle action — can be projected onto a chosen fully (anti-)symmetric representation. By considering F families of auxiliary variables, we describe how to extend the model to arbitrary tensor products of F reducible representations, which realises a U( F ) "flavour" symmetry on the world-line particle model. Gauging this symmetry allows the introduction of constraints on the Hilbert space of the colour fields which can be used to project onto an arbitrary irreducible representation, specified by a certain Young tableau. In particular the occupation numbers of the wavefunction — i.e. the lengths of the columns (rows) of the Young tableau — are fixed through the introduction of Chern-Simons terms. We verify this projection by calculating the number of colour degrees of freedom associated to the matter field. We suggest that, using the worldline approach to quantum field theory, this mechanism will allow the calculation of one-loop scattering amplitudes with the virtual particle in an arbitrary representation of the gauge group.
Inverse semigroups the theory of partial symmetries
Lawson, Mark V
1998-01-01
Symmetry is one of the most important organising principles in the natural sciences. The mathematical theory of symmetry has long been associated with group theory, but it is a basic premise of this book that there are aspects of symmetry which are more faithfully represented by a generalization of groups called inverse semigroups. The theory of inverse semigroups is described from its origins in the foundations of differential geometry through to its most recent applications in combinatorial group theory, and the theory tilings.
Web Environments for Group-Based Project Work in Higher Education
Diepen, van Nico; Collis, Betty; Andernach, Toine
1997-01-01
We discuss problems confronting the use of group-based project work as an instructional strategy in higher education and describe two courses in which course-specific World Wide Web (Web) environments have evolved over a series of course sequences and are used both as tool environments for group-pro
A Wiki-Based Group Project in an Inorganic Chemistry Foundation Course
Kristian, Kathleen E.
2015-01-01
A semester-long group project that utilizes wiki sites to enhance collaboration was developed for a foundation course in inorganic chemistry. Through structured assignments, student groups use metal-based or metal-combating therapeutic agents as a model for applying and understanding course concepts; they also gain proficiency with scientific- and…
Peer Assessment in Group Projects Accounting for Assessor Reliability by an Iterative Method
Ko, Sung-Seok
2014-01-01
This study proposes an advanced method to factor in the contributions of individual group members engaged in an integrated group project using peer assessment procedures. Conway et al. proposed the Individual Weight Factor (IWF) method for peer assessment which has been extensively developed over the years. However, most methods associated with…
A Wiki-Based Group Project in an Inorganic Chemistry Foundation Course
Kristian, Kathleen E.
2015-01-01
A semester-long group project that utilizes wiki sites to enhance collaboration was developed for a foundation course in inorganic chemistry. Through structured assignments, student groups use metal-based or metal-combating therapeutic agents as a model for applying and understanding course concepts; they also gain proficiency with scientific- and…
Jensen, Murray; Mattheis, Allison; Johnson, Brady
2012-01-01
Students in an interdisciplinary undergraduate introductory course were required to complete a group video project focused on nutrition and healthy eating. A mixed-methods approach to data collection involved observing and rating video footage of group work sessions and individual and focus group interviews. These data were analyzed and used to evaluate the effectiveness of the assignment in light of two student learning outcomes and two student development outcomes at the University of Minnesota. Positive results support the continued inclusion of the project within the course, and recommend the assignment to other programs as a viable means of promoting both content learning and affective behavioral objectives. PMID:22383619
Tlhoaele, Malefyane; Suhre, Cor; Hofman, Adriaan
2016-05-01
Cooperative learning may improve students' motivation, understanding of course concepts, and academic performance. This study therefore enhanced a cooperative, group-project learning technique with technology resources to determine whether doing so improved students' deep learning and performance. A sample of 118 engineering students, randomly divided into two groups, participated in this study and provided data through questionnaires issued before and after the experiment. The results, obtained through analyses of variance and structural equation modelling, reveal that technology-enhanced, cooperative, group-project learning improves students' comprehension and academic performance.
Zhou, Chunfang; Kolmos, Anette; Nielsen, Jens Frederik Dalsgaard
2012-01-01
In this paper, we explore how engineering students are motivated to develop group creativity in a Problem and Project- Based Learning (PBL) environment. Theoretically, we take a social cultural approach to group creativity and emphasize the influences of a learning environment on student motivation...... creativity. Thus, the supervisors are encouraged to be more aware of the complex relationships between student, teacher and task and the student response....... in group creativity development. Empirically, a case study was carried out on a student satellite project in the Department of Electronic System at Aalborg University in Denmark, by using qualitative methods including interviews and observation. The findings show that student motivation is stimulated...
Zhou, Chunfang; Kolmos, Anette; Nielsen, Jens Frederik Dalsgaard
2012-01-01
In this paper, we explore how engineering students are motivated to develop group creativity in a Problem and Project- Based Learning (PBL) environment. Theoretically, we take a social cultural approach to group creativity and emphasize the influences of a learning environment on student motivation...... in group creativity development. Empirically, a case study was carried out on a student satellite project in the Department of Electronic System at Aalborg University in Denmark, by using qualitative methods including interviews and observation. The findings show that student motivation is stimulated...
Symmetry and symmetry breaking in particle physics
Tsou, ST
1998-01-01
Symmetry, in particular gauge symmetry, is a fundamental principle in theoretical physics. It is intimately connected to the geometry of fibre bundles. A refinement to the gauge principle, known as ``spontaneous symmetry breaking'', leads to one of the most successful theories in modern particle physics. In this short talk, I shall try to give a taste of this beautiful and exciting concept.
Neculai Curteanu
2007-07-01
Full Text Available The aim of this paper is to investigate the syntactic / semantic substructures (called subgroups of the Romanian verbal group (VG [12], or verbal complex [25], starting with the achievements in the literature, and melted into the device of direct and inverse functional projection within FX-bar theory [7]. The paper examines several problems and their solutions for the syntactic-semantic theories of VG, as discussed in some fundamental papers, and we offer our explanation on the involved syntactic phenomena, the emphasis falling on the VG substructures (verbal subgroups, VSGs, VSG boundaries and composition within VG, direct and inverse FX-bar projections of VG, VG parsing, lexical semantics and intensional~/ extensional logic representations of the Romanian (verbal or nominal predicate.
Wing-Yi Cheng, Rebecca; Lam, Shui-Fong; Chung-Yan Chan, Joanne
2008-01-01
Background: There has been an ongoing debate about the inconsistent effects of heterogeneous ability grouping on students in small group work such as project-based learning. Aim: The present research investigated the roles of group heterogeneity and processes in project-based learning. At the student level, we examined the interaction effect…
Configuring Web-based Media for Communication in Dispersed Project Groups
Scheepers, Rens; Nicolajsen, Hanne Westh
2006-01-01
meetings, telephone) are not always viable options. Instead, computer-based communication media such as email, project intranets and extranets become surrogate conduits for day-to-day project communication and exchange of project-related content. We examined the effect of different media configurations...... on the nature of content created by the project groups. We found that configuration decisions, notably the responsibility for content provision and who had access to content, influenced medium choice and the nature of communication taking place via the medium. More substantive content resulted when content...... provision was decentralized and access to content restricted to specific sub-groups. Content providers resorted to superficial use of "openly configured" Web-based media or used email if unsure who could access content, or if they suspected that recipients might lack the background to understand...
The Perception of Critical Success Factors for PPP Projects in Different Stakeholder Groups
Joanna Węgrzyn
2016-06-01
Full Text Available Objective: The main goal of the research is to enhance understanding which factors are perceived as critical for the success of public-private partnerships (PPPs by different stakeholder groups on different stages of the project life cycle. Research Design & Methods: The paper builds on a larger research study looking at the development of the best practice framework for PPPs. The research is based on both a literature review and empirical studies. To examinethe perception of critical success factors (CSFs a questionnaire was conducted within different stakeholder groups for PPPs in Poland. Findings: The article concentrates on one of the two dimensions ofa PPP project success which is the idea of critical success factors. The research reveals that public and private parties do not share common perception of the PPPsuccess. In general, the private sector assigns lower values to the CSFs analysed from the whole life perspective of a PPP project. Implications & Recommendations: The research indicates that the interpretation of a PPP project success depends of the stakeholders' role in the project. Future research might try to integrate a wider range of stakeholdersengaged in PPPs such as financial institutions or a final user of the services provided under a PPP project. Contribution & Value Added: The results of the study provides helpful information to identify areas that stakeholders should pay a specialattention to in order to achieve the success of a PPP project.
Nonlocalization of Nonlocal Symmetry and Symmetry Reductions of the Burgers Equation
金艳; 贾曼; 楼森岳
2012-01-01
Symmetry reduction method is one of the best ways to find exact solutions. In this paper, we study the possibility of symmetry reductions of the well known Burgers equation including the nonlocal symmetry. The related new group Jnvariant solutions are obtained. Especially, the interactions among solitons, Airy waves, and Kummer waves are explicitly given.
Perception of Mirror Symmetry in Autism Spectrum Disorders
Falter, Christine M.; Bailey, Anthony J.
2012-01-01
Gestalt grouping in autism spectrum disorders (ASD) is selectively impaired for certain organization principles but for not others. Symmetry is a fundamental Gestalt principle characterizing many biological shapes. Sensitivity to symmetry was tested using the Picture Symmetry Test, which requires finding symmetry lines on pictures. Individuals…
External symmetry in general relativity
Cotaescu, I I
2000-01-01
We propose a generalization of the isometry transformations to the geometric context of the field theories with spin where the local frames are explicitly involved. We define the external symmetry transformations as isometries combined with suitable tetrad gauge transformations and we show that these form a group which is locally isomorphic with the isometry one. We point out that the symmetry transformations that leave invariant the equations of the fields with spin have generators with specific spin terms which represent new physical observables. The examples we present are the generators of the central symmetry and those of the maximal symmetries of the de Sitter and anti-de Sitter spacetimes derived in different tetrad gauge fixings. Pacs: 04.20.Cv, 04.62.+v, 11.30.-j
Michele Belliveau
2011-03-01
Full Text Available Changing demographics and an emphasis on competency-based social work education call for innovative approaches to the delivery of curricular content. In an effort to introduce BSW students to the socio-political issues facing the local Latino immigrant community, a service-learning project was developed in collaboration with the Spanish Language Department and a local middle school. An analysis of outcomes from social work student evaluations showed that students engaged with the community and issues in new and unexpected ways. Through their engagement in a cross-cultural group project, students developed greater cultural competency, honed their group practice skills in an unfamiliar context, provided a needed service to the community, and raised their awareness about the working conditions of new immigrants as part of a developing framework for social action. Details and implications of the project as a means to build student competencies are described.
"Fools Rush In": Developing Cross-Cultural Sensitivity Using Film-Based Group Projects.
Tidwell, Charles H., Jr.
Although role playing games and self-awareness surveys are typical methods of developing cross-cultural sensitivity, this presentation advocates the use small group projects focusing on feature films such as "Fools Rush In" as an effective class or training exercise to develop sensitivity to other cultures. Despite some disadvantages…
Power Distance and Group Dynamics of an International Project Team: A Case Study
Paulus, Trena M.; Bichelmeyer, Barbara; Malopinsky, Larissa; Pereira, Maura; Rastogi, Polly
2005-01-01
Project-based team activities are commonly used in higher education. Teams comprised of members from different national cultures can be faced with unique challenges during the creative process. Hofstede's (1991) cultural dimension of power distance was used to examine one such design team's intra- and inter-group interactions in a graduate-level…
Bailey, Sarah; Barber, Larissa K.; Ferguson, Amanda J.
2015-01-01
Group projects are often used in psychology courses to prepare students for future collaborative work. However, psychology alumni report that their education did not adequately prepare them for collaborative work. To better understand these perceptions, this study examined how instructor contributions (involvement and evaluation techniques)…
Group Projects Using Clients versus Not Using Clients: Do Students Perceive Any Differences?
Parsons, Amy L.; Lepkowska-White, Elzbieta
2009-01-01
Today's educators are faced with the challenge of preparing undergraduate students to be productive employees who can communicate effectively, work well in teams, and solve problems, as well as demonstrate content knowledge. Group projects are one tool that educators can use to help students develop these key skills. Educators may be tempted to…
Skirbekk, Vegard; Potancoková, Michaela; Hackett, Conrad; Stonawski, Marcin
2016-11-09
The religious landscape of older adults around the world is changing profoundly. Yet until now, no study has chronicled these changes or compared expected aging patterns of religious groups. Differential aging among religious groups can have important economic and social consequences. This study estimates and projects the future religious composition by age at the global and regional levels. This study presents estimates of age structures by religion for 2010 and projections until 2050. It is based on analyses of more than 2,500 censuses, registers, and surveys from 198 countries. Regional and global results are the aggregate of demographic projections carried out at the country level. In 2010, Muslims were least likely to be aged 60 or older (7% of all Muslims), and Jews were most likely to be in this age group (20% of all Jews). By 2050, we project that Buddhists and the religiously unaffiliated will have the oldest populations (both will have 32% above the age of 60), whereas Muslims will remain the youngest religious group (with only 16% above the age of 60). Christians will, globally, age relatively slowly, from 14% to 21% above the age of 60 from 2010 to 2050. The religious landscape among the world's seniors will change fundamentally in the coming years, due to the combination of rapid aging among the religiously unaffiliated and Buddhist populations and the persistence of relatively young age structures among Muslims and Christians, which are the dominant religions in Africa.
Does Like Seek Like?: The Formation of Working Groups in a Programming Project
Sanou Gozalo, Eduard; Hernández-Fernández, Antoni; Arias, Marta; Ferrer-i-Cancho, Ramon
2017-01-01
In a course of the degree of computer science, the programming project has changed from individual to teamed work, tentatively in couples (pair programming). Students have full freedom to team up with minimum intervention from teachers. The analysis of the working groups made indicates that students do not tend to associate with students with a…
Napa River Restoration Project: Oakville to Oak Knoll Reach, Group A Sites 21-23
Information about the SFBWQP Napa River Restoration Project: Oakville to Oak Knoll Reach, Group A Sites 21-23, part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquatic resources
Tlhoaele, Malefyane; Suhre, Cor; Hofman, Adriaan
2016-01-01
Cooperative learning may improve students' motivation, understanding of course concepts, and academic performance. This study therefore enhanced a cooperative, group-project learning technique with technology resources to determine whether doing so improved students' deep learning and performance. A sample of 118 engineering students, randomly…
Jian Guo
2013-01-01
Full Text Available Information system (IS project selection is of critical importance to every organization in dynamic competing environment. The aim of this paper is to develop a hybrid multicriteria group decision making approach based on intuitionistic fuzzy theory for IS project selection. The decision makers’ assessment information can be expressed in the form of real numbers, interval-valued numbers, linguistic variables, and intuitionistic fuzzy numbers (IFNs. All these evaluation pieces of information can be transformed to the form of IFNs. Intuitionistic fuzzy weighted averaging (IFWA operator is utilized to aggregate individual opinions of decision makers into a group opinion. Intuitionistic fuzzy entropy is used to obtain the entropy weights of the criteria. TOPSIS method combined with intuitionistic fuzzy set is proposed to select appropriate IS project in group decision making environment. Finally, a numerical example for information system projects selection is given to illustrate application of hybrid multi-criteria group decision making (MCGDM method based on intuitionistic fuzzy theory and TOPSIS method.
Group Communication and Critical Thinking Competence Development Using a Reality-Based Project
Paulson, Edward
2011-01-01
The presented merger and acquisition classroom exercise is based on a real yet incomplete transaction transpiring during the period of the class. The approach enables adult students to apply their previously acquired business experience to a strategic analysis project facilitating the development of group communication, critical thinking, and…
Nucleus Retroambiguus Projections To Lumbosacral Mononeuronal Cell Groups In The Male Cat.
VanderHorst, Veronique G.J.M.; Holstege, Gert
1997-01-01
Recently, in the female cat, nucleus retroambiguus (NRA) projections have been described as distinct motoneuronal cell groups in the lumbar enlargement, possibly involved in lordosis behavior. The present study deals with the NRA-lumbosacral pathway in the male cat. Lumbosacral injections of wheat g
Nucleus retroambiguous projections to lumbosacral motoneuronal cell groups in the male cat
Vanderhorst, VGJM; Holstege, G
1997-01-01
Recently, in the female cat, nucleus retroambiguus (NRA) projections have been described as distinct motoneuronal cell groups in the lumbar enlargement, possibly involved in lordosis behavior. The present study deals with the NRA-lumbosacral pathway in the male cat, Lumbosacral injections of wheat g
Using a Virtual Learning Environment to Manage Group Projects: A Case Study
Cleary, Yvonne; Marcus-Quinn, Ann
2008-01-01
Virtual Learning Environments (VLEs) are increasingly used by Higher Education Institutions to manage and enhance teaching and learning, and research. Discussion, chat, scheduling, and other collaboration tools make VLEs especially useful systems for designing and managing complex group projects. In the spring semester of 2006, students at the…
Catch It If You Can: How Contagious Motivation Improves Group Projects and Course Satisfaction
Krishen, Anjala S.
2013-01-01
This article proposes a theory-based contagious motivation model focusing on enhancing student perceptions of group projects and ultimately course satisfaction. Moreover, drawing from both pedagogical and organizational behavior literatures, a model is presented that ties together intrinsic motivation theory with social contagion and…
Taking Ownership of Learning in a Large Class: Group Projects and a Mini-Conference
Borda, Emily J.; Kriz, George S.; Popejoy, Kate L.; Dickinson, Alison K.; Olson, Amy L.
2009-01-01
Helping students take ownership of their learning is often a challenge in a large lecture course. In this article, the authors describe a nature of science-oriented group project in a chemistry course in which students gave presentations in concurrent conference sessions as well as its impact on student learning as evidenced through multiple data…
Taking Ownership of Learning in a Large Class: Group Projects and a Mini-Conference
Borda, Emily J.; Kriz, George S.; Popejoy, Kate L.; Dickinson, Alison K.; Olson, Amy L.
2009-01-01
Helping students take ownership of their learning is often a challenge in a large lecture course. In this article, the authors describe a nature of science-oriented group project in a chemistry course in which students gave presentations in concurrent conference sessions as well as its impact on student learning as evidenced through multiple data…
The Study of Small Groups and Microevolution: A Project for Physical Anthropology.
Rice, Patricia C.
1985-01-01
Describes a hands-on project in which anthropology students play the role of professional physical anthropologist in collecting and analyzing data on a small group of contemporary humans. Use of simulated data to represent ancestral populations results in an analysis of microevolution. (KH)
Bailey, Sarah; Barber, Larissa K.; Ferguson, Amanda J.
2015-01-01
Group projects are often used in psychology courses to prepare students for future collaborative work. However, psychology alumni report that their education did not adequately prepare them for collaborative work. To better understand these perceptions, this study examined how instructor contributions (involvement and evaluation techniques)…
United Nations Economic and Social Commission for Asia and the Pacific, Bangkok (Thailand).
A group of experts on population projections was convened in Thailand in late 1975. It was organized by the United Nations Economic and Social Commission for Asia and the Pacific. This report is the result of background papers used at the conference, reactions to the papers, and further writing. Chapter headings are: (1) Introduction; (2) The Role…
Innovation Group Will Invest 20 Billion Yuan to Launch a Hard Aluminum Alloy Project
2012-01-01
<正>On November 20, the People’s Government of Tongliao City of Inner Mongolia, the People’s Government of Huolinguole City and Shandong-based Innovation Group signed an investment framework agreement on a new-type hard aluminum alloy project. Under the agreement
Notes on generalized global symmetries in QFT
Sharpe, Eric [Department of Physics MC 0435, 850 West Campus Drive, Virginia Tech, Blacksburg, VA (United States)
2015-11-15
It was recently argued that quantum field theories possess one-form and higher-form symmetries, labelled 'generalized global symmetries.' In this paper, we describe how those higher-form symmetries can be understood mathematically as special cases of more general 2-groups and higher groups, and discuss examples of quantum field theories admitting actions of more general higher groups than merely one-form and higher-form symmetries. We discuss analogues of topological defects for some of these higher symmetry groups, relating some of them to ordinary topological defects. We also discuss topological defects in cases in which the moduli 'space' (technically, a stack) admits an action of a higher symmetry group. Finally, we outline a proposal for how certain anomalies might potentially be understood as describing a transmutation of an ordinary group symmetry of the classical theory into a 2-group or higher group symmetry of the quantum theory, which we link to WZW models and bosonization. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Cubic Icosahedra? A Problem in Assigning Symmetry
Lloyd, D. R.
2010-01-01
There is a standard convention that the icosahedral groups are classified separately from the cubic groups, but these two symmetry types have been conflated as "cubic" in some chemistry textbooks. In this note, the connection between cubic and icosahedral symmetries is examined, using a simple pictorial model. It is shown that octahedral and…
SASS: a symmetry adapted stochastic search algorithm exploiting site symmetry.
Wheeler, Steven E; Schleyer, Paul V R; Schaefer, Henry F
2007-03-14
A simple symmetry adapted search algorithm (SASS) exploiting point group symmetry increases the efficiency of systematic explorations of complex quantum mechanical potential energy surfaces. In contrast to previously described stochastic approaches, which do not employ symmetry, candidate structures are generated within simple point groups, such as C2, Cs, and C2v. This facilitates efficient sampling of the 3N-6 Pople's dimensional configuration space and increases the speed and effectiveness of quantum chemical geometry optimizations. Pople's concept of framework groups [J. Am. Chem. Soc. 102, 4615 (1980)] is used to partition the configuration space into structures spanning all possible distributions of sets of symmetry equivalent atoms. This provides an efficient means of computing all structures of a given symmetry with minimum redundancy. This approach also is advantageous for generating initial structures for global optimizations via genetic algorithm and other stochastic global search techniques. Application of the SASS method is illustrated by locating 14 low-lying stationary points on the cc-pwCVDZ ROCCSD(T) potential energy surface of Li5H2. The global minimum structure is identified, along with many unique, nonintuitive, energetically favorable isomers.
Quantum mechanics. Symmetries. 5. corr. ed.; Quantenmechanik. Symmetrien
Greiner, Walter [Frankfurt Univ. (Germany). Frankfurt Inst. for Advanced Studies; Mueller, Berndt [Duke Univ., Durham, NC (United States). Dept. of Physics
2014-07-01
The volume quantum mechanics treats the as elegant as mighty theory of the symmetry groups and their application in quantum mechanics and the theory of the elementary particles. By means of many examples and problems with worked-out solutions the application of the fundamental principles to realistic problems is elucidated. The themes are symmetries in quantum mechanics, representations of the algebra of the angular momentum operators as generators of the SO(3) group. fundamental properties of Lie groups as mathematical supplement, symmetry groups and their physical meaning, thr isospin group, the hypercharge, quarks and the symmetry group SU(3), representations of the permutation group and Young diagrams, group characters as mathematical supplement, charm and the symmetry group SU(4), Cartan-Weyl claasification as mathematical supplement, special discrete symmetries, dynamical symmetries and the hydrogen atom, non-compact Lie groups as mathematical supplement, a proof of Racah's theorem.
Beyond bilateral symmetry: geometric morphometric methods for any type of symmetry
Klingenberg Christian
2011-09-01
Full Text Available Abstract Background Studies of symmetric structures have made important contributions to evolutionary biology, for example, by using fluctuating asymmetry as a measure of developmental instability or for investigating the mechanisms of morphological integration. Most analyses of symmetry and asymmetry have focused on organisms or parts with bilateral symmetry. This is not the only type of symmetry in biological shapes, however, because a multitude of other types of symmetry exists in plants and animals. For instance, some organisms have two axes of reflection symmetry (biradial symmetry; e.g. many algae, corals and flowers or rotational symmetry (e.g. sea urchins and many flowers. So far, there is no general method for the shape analysis of these types of symmetry. Results We generalize the morphometric methods currently used for the shape analysis of bilaterally symmetric objects so that they can be used for analyzing any type of symmetry. Our framework uses a mathematical definition of symmetry based on the theory of symmetry groups. This approach can be used to divide shape variation into a component of symmetric variation among individuals and one or more components of asymmetry. We illustrate this approach with data from a colonial coral that has ambiguous symmetry and thus can be analyzed in multiple ways. Our results demonstrate that asymmetric variation predominates in this dataset and that its amount depends on the type of symmetry considered in the analysis. Conclusions The framework for analyzing symmetry and asymmetry is suitable for studying structures with any type of symmetry in two or three dimensions. Studies of complex symmetries are promising for many contexts in evolutionary biology, such as fluctuating asymmetry, because these structures can potentially provide more information than structures with bilateral symmetry.
On quaternions and octonions their geometry, arithmetic, and symmetry
AUTHOR|(CDS)2067326
2003-01-01
This book investigates the geometry of quaternion and octonion algebras. Following a comprehensive historical introduction, the book illuminates the special properties of 3- and 4-dimensional Euclidean spaces using quaternions, leading to enumerations of the corresponding finite groups of symmetries. The second half of the book discusses the less familiar octonion algebra, concentrating on its remarkable "triality symmetry" after an appropriate study of Moufang loops. The authors also describe the arithmetics of the quaternions and octonions. The book concludes with a new theory of octonion factorization. Topics covered include the geometry of complex numbers, quaternions and 3-dimensional groups, quaternions and 4-dimensional groups, Hurwitz integral quaternions, composition algebras, Moufang loops, octonions and 8-dimensional geometry, integral octonions, and the octonion projective plane.
Learning from data to design functional materials without inversion symmetry
Balachandran, Prasanna V.; Young, Joshua; Lookman, Turab; Rondinelli, James M.
2017-02-01
Accelerating the search for functional materials is a challenging problem. Here we develop an informatics-guided ab initio approach to accelerate the design and discovery of noncentrosymmetric materials. The workflow integrates group theory, informatics and density-functional theory to uncover design guidelines for predicting noncentrosymmetric compounds, which we apply to layered Ruddlesden-Popper oxides. Group theory identifies how configurations of oxygen octahedral rotation patterns, ordered cation arrangements and their interplay break inversion symmetry, while informatics tools learn from available data to select candidate compositions that fulfil the group-theoretical postulates. Our key outcome is the identification of 242 compositions after screening ~3,200 that show potential for noncentrosymmetric structures, a 25-fold increase in the projected number of known noncentrosymmetric Ruddlesden-Popper oxides. We validate our predictions for 19 compounds using phonon calculations, among which 17 have noncentrosymmetric ground states including two potential multiferroics. Our approach enables rational design of materials with targeted crystal symmetries and functionalities.
Mathieu Moonshine and Symmetry Surfing
Gaberdiel, Matthias R; Paul, Hynek
2016-01-01
Mathieu Moonshine, the observation that the Fourier coefficients of the elliptic genus on K3 can be interpreted as dimensions of representations of the Mathieu group M24, has been proven abstractly, but a conceptual understanding in terms of a representation of the Mathieu group on the BPS states, is missing. Some time ago, Taormina and Wendland showed that such an action can be naturally defined on the lowest non-trivial BPS states, using the idea of `symmetry surfing', i.e., by combining the symmetries of different K3 sigma models. In this paper we find non-trivial evidence that this construction can be generalized to all BPS states.
Symposium Symmetries in Science XIII
Gruber, Bruno J; Yoshinaga, Naotaka; Symmetries in Science XI
2005-01-01
This book is a collection of reviews and essays about the recent developments in the area of Symmetries and applications of Group Theory. Contributions have been written mostly at the graduate level but some are accessible to advanced undergraduates. The book is of interest to a wide audience and covers a broad range of topics with a strong degree of thematical unity. The book is part of a Series of books on Symmetries in Science and may be compared to the published Proceedings of the Colloquia on Group Theoretical Methods in Physics. Here, however, prevails a distinguished character for presenting extended reviews on present applications to Science, not restricted to Theoretical Physics.
Ermolenko, Alexander E; Perepada, Elena A
2007-01-01
The paper contains a description of basic regularities in the manifestation of symmetry of human structural organization and its ontogenetic and phylogenetic development. A concept of macrobiocrystalloid with inherent complex symmetry is proposed for the description of the human organism in its integrity. The symmetry can be characterized as two-plane radial (quadrilateral), where the planar symmetry is predominant while the layout of organs of radial symmetry is subordinated to it. Out of the two planes of symmetry (sagittal and horizontal), the sagittal plane is predominant. The symmetry of the chromosome, of the embrio at the early stages of cell cleavage as well as of some organs and systems in their phylogenetic development is described. An hypothesis is postulated that the two-plane symmetry is formed by two mechanisms: a) the impact of morphogenetic fields of the whole crystalloid organism during embriogenesis and, b) genetic mechanisms of the development of chromosomes having two-plane symmetry.
Mixed symmetry tensors in the worldline formalism
Corradini, Olindo
2016-01-01
We consider the first quantised approach to quantum field theory coupled to a non-Abelian gauge field. Representing the colour degrees of freedom with a single family of auxiliary variables the matter field transforms in a reducible representation of the gauge group which - by adding a suitable Chern-Simons term to the particle action - can be projected onto a chosen fully (anti-)symmetric representation. By considering F families of auxiliary variables, we describe how to extend the model to arbitrary tensor products of F reducible representations, which realises a U(F) "flavour" symmetry on the worldline particle model. Gauging this symmetry allows the introduction of constraints on the Hilbert space of the colour fields which can be used to project onto an arbitrary irreducible representation, specified by a certain Young Tableau. In particular the occupation numbers of the wavefunction - i.e. the lengths of the columns (rows) of the Young Tableau - are fixed through the introduction of Chern-Simons terms....
Magnetic translation group on Abrikosov lattice
Goto, Akira
1996-02-01
We investigate the magnetic translational symmetry of the Bogoliubov-de Gennes equation describing quasiparticles in the vortex lattice state. Magnetic translation group is formulated for the quasiparticles and the generalized Bloch theorem is established. Projection operators are obtained and used to construct the symmetry adopted basis functions. Careful treatment of the phase of the pair potential and its quasiperiodicity enable us to get the magnetic Wannier functions, which are utilized to justify a part of Canel's assertion about the effective Hamiltonian theory.
The Perception of Symmetry in Depth: Effect of Symmetry Plane Orientation
Bart Farell
2015-04-01
Full Text Available The visual system is sensitive to symmetries in the frontoparallel plane, and bilateral symmetry about a vertical axis has a particular salience. However, these symmetries represent only a subset of the symmetries realizable in three-dimensional space. The retinal image symmetries formed when viewing natural objects are typically the projections of three-dimensional objects—animals, for example—that have a symmetry in depth. To characterize human sensitivity to depth symmetry, experiments measured observers’ ability to discriminate stereo displays that were symmetrically distributed in depth and those that were asymmetrically distributed. Disparity values were distributed about one of four planes passing through the z-axis and differing in frontoparallel orientation. Asymmetrical patterns were generated by perturbing one of these disparities. Symmetrical-asymmetrical discrimination thresholds were lowest for symmetry about the vertical plane and highest for the horizontal plane. Thresholds for discriminating repetitions and non-repetitions of depth values did not differ across the four planes, whereas discriminations for depth gradients differed from both the symmetry and repetition cases. The heightened sensitivity to symmetry in depth about the vertical plane is a 3-D analog of 2-D mirror-image symmetry performance and could be its source.
Noether symmetry and Lie symmetry of discrete holonomic systems with dependent coordinates
Shi Shen-Yang; Huang Xiao-Hong
2008-01-01
The Noether symmetry,the Lie symmetry and the conserved quantity of discrete holonomic systems with dependent coordinates are investigated in this paper.The Noether symmetry provides a discrete Noether identity and a conserved qu中antity of the system.The invariance of discrete motion equations under infinitesimal transformation groups is defined as the Lie symmetry,and the condition of obtaining the Noether conserved quantity from the Lie symmetry is also presented.An example is discussed to show the applications of the results.
Configuring Web-based Media for Communication in Dispersed Project Groups
Scheepers, Rens; Nicolajsen, Hanne Westh
2006-01-01
the communicated. We explain these findings by proposing a “triad” of three interrelated concepts arising from both media richness theory and genre theory: content, medium and genre. We argue that substantive use (and acceptance of the medium and content) occurs when there is a “fit” between genre, medium...... meetings, telephone) are not always viable options. Instead, computer-based communication media such as email, project intranets and extranets become surrogate conduits for day-to-day project communication and exchange of project-related content. We examined the effect of different media configurations...... provision was decentralized and access to content restricted to specific sub-groups. Content providers resorted to superficial use of “openly configured” Web-based media or used email if unsure who could access content, or if they suspected that recipients might lack the background to understand...
Tetsuo Deguchi
2011-06-01
Full Text Available We show some symmetry relations among the correlation functions of the integrable higher-spin XXX and XXZ spin chains, where we explicitly evaluate the multiple integrals representing the one-point functions in the spin-1 case. We review the multiple-integral representations of correlation functions for the integrable higher-spin XXZ chains derived in a region of the massless regime including the anti-ferromagnetic point. Here we make use of the gauge transformations between the symmetric and asymmetric R-matrices, which correspond to the principal and homogeneous gradings, respectively, and we send the inhomogeneous parameters to the set of complete 2s-strings. We also give a numerical support for the analytical expression of the one-point functions in the spin-1 case.
Brading, Katherine; Castellani, Elena
2010-01-01
Preface; Copyright acknowledgements; List of contributors; 1. Introduction; Part I. Continuous Symmetries: 2. Classic texts: extracts from Weyl and Wigner; 3. Review paper: On the significance of continuous symmetry to the foundations of physics C. Martin; 4. The philosophical roots of the gauge principle: Weyl and transcendental phenomenological idealism T. Ryckman; 5. Symmetries and Noether's theorems K. A. Brading and H. R. Brown; 6. General covariance, gauge theories, and the Kretschmann objection J. Norton; 7. The interpretation of gauge symmetry M. Redhead; 8. Tracking down gauge: an ode to the constrained Hamiltonian formalism J. Earman; 9. Time-dependent symmetries: the link between gauge symmetries and indeterminism D. Wallace; 10. A fourth way to the Aharanov-Bohm effect A. Nounou; Part II. Discrete Symmetries: 11. Classic texts: extracts from Lebniz, Kant and Black; 12. Review paper: Understanding permutation symmetry S. French and D. Rickles; 13. Quarticles and the identity of discernibles N. Hugget; 14. Review paper: Handedness, parity violation, and the reality of space O. Pooley; 15. Mirror symmetry: what is it for a relational space to be orientable? N. Huggett; 16. Physics and Leibniz's principles S. Saunders; Part III. Symmetry Breaking: 17: Classic texts: extracts from Curie and Weyl; 18. Extract from G. Jona-Lasinio: Cross-fertilization in theoretical physics: the case of condensed matter and particle physics G. Jona-Lasinio; 19. Review paper: On the meaning of symmetry breaking E. Castellani; 20. Rough guide to spontaneous symmetry breaking J. Earman; 21. Spontaneous symmetry breaking: theoretical arguments and philosophical problems M. Morrison; Part IV. General Interpretative Issues: 22. Classic texts: extracts from Wigner; 23. Symmetry as a guide to superfluous theoretical structure J. Ismael and B. van Fraassen; 24. Notes on symmetries G. Belot; 25. Symmetry, objectivity, and design P. Kosso; 26. Symmetry and equivalence E. Castellani.
Rosensteel, George
1995-01-01
Riemann ellipsoids model rotating galaxies when the galactic velocity field is a linear function of the Cartesian coordinates of the galactic masses. In nuclear physics, the kinetic energy in the linear velocity field approximation is known as the collective kinetic energy. But, the linear approximation neglects intrinsic degrees of freedom associated with nonlinear velocity fields. To remove this limitation, the theory of symplectic dynamical symmetry is developed for classical systems. A classical phase space for a self-gravitating symplectic system is a co-adjoint orbit of the noncompact group SP(3,R). The degenerate co-adjoint orbit is the 12 dimensional homogeneous space Sp(3,R)/U(3), where the maximal compact subgroup U(3) is the symmetry group of the harmonic oscillator. The Hamiltonian equations of motion on each orbit form a Lax system X = (X,F), where X and F are elements of the symplectic Lie algebra. The elements of the matrix X are the generators of the symplectic Lie algebra, viz., the one-body collective quadratic functions of the positions and momenta of the galactic masses. The matrix F is composed from the self-gravitating potential energy, the angular velocity, and the hydostatic pressure. Solutions to the hamiltonian dynamical system on Sp(3,R)/U(3) are given by symplectic isospectral deformations. The Casimirs of Sp(3,R), equal to the traces of powers of X, are conserved quantities.
Assessing group dynamics by individual radio satellites in the Mars-500 project
Johannes, Bernd; Sitev, A. S.; Vinokhodova, A. G.; Salnitski, V.P.; Savchenko, Eduardo; Artyukhova, Anna; Bubeev, Yuri
2013-01-01
In a methodological feasibility experiment a wireless group structure (WLGS) monitor system was developed and tested during the Mars500 project. Twice a week each crew member brought a small short-distance radio satellite registering the presence of any other sensor in-room in five second intervals during the wake time. Six satellites were additionally attached to the wall of the simulator’s main compartments. The time being together was registered as well as the signal amplitude providing an...
Rašin, Andrija
1994-01-01
We discuss the idea of approximate flavor symmetries. Relations between approximate flavor symmetries and natural flavor conservation and democracy models is explored. Implications for neutrino physics are also discussed.
Joe Rosen
2005-12-01
Full Text Available Abstract: The symmetry principle is described in this paper. The full details are given in the book: J. Rosen, Symmetry in Science: An Introduction to the General Theory (Springer-Verlag, New York, 1995.
Using and Applying Focus Groups in Climate Change Impact Assessment Projects
DeLorme, D.; Hagen, S.
2011-12-01
The focus group social science research method is an efficient and flexible data collection tool with broad applicability across disciplines and contexts. Through group dynamics, this interviewing approach offers strengths in gathering candid, spontaneous comments and detailed firsthand descriptions from stakeholders' perspectives. The method, which can stand alone or be integrated with other research frameworks, has much potential for helping to manage complex issues of global change. For optimal outcomes, however, careful planning and procedures are paramount. This presentation offers guidance in this regard via examples, tips, and lessons learned from a multidisciplinary NOAA-funded project: Ecological Effects of Sea Level Rise in the Northern Gulf of Mexico (EESLR-NGOM). Focus groups are a key component of the EESLR-NGOM project as they are being used to better understand coastal resource managers' operational and information behaviors and needs regarding sea level rise (SLR), erosion, and hurricane storm surge impact; to learn how to best develop and translate the project's expected scientific results into straightforward, useful, and readily-disseminated products; and to gather outreach recommendations. As part of an EESLR-NGOM project kickoff workshop, 12 coastal resource managers participated voluntarily in a focus group. A summary of findings and illustrative participant quotations will be included in the presentation. The initial focus group was productive in gaining insights into challenges and opportunities associated with a climate change project such as the EESLR-NGOM. It highlighted the importance of considering the interrelationships of natural and built environments and new avenues for resilience and sustainability. The coastal resource managers are not only end-users but also opinion leaders in their local communities who will diffuse this information widely through their networks of other potential end-users. Engaging coastal resource managers in
Localization of Nonlocal Symmetries and Symmetry Reductions of Burgers Equation
Wu, Jian-Wen; Lou, Sen-Yue; Yu, Jun
2017-05-01
The nonlocal symmetries of the Burgers equation are explicitly given by the truncated Painlevé method. The auto-Bäcklund transformation and group invariant solutions are obtained via the localization procedure for the nonlocal residual symmetries. Furthermore, the interaction solutions of the solition-Kummer waves and the solition-Airy waves are obtained. Supported by the Global Change Research Program China under Grant No. 2015CB953904, the National Natural Science Foundations of China under Grant Nos. 11435005, 11175092, and 11205092, Shanghai Knowledge Service Platform for Trustworthy Internet of Things under Grant No. ZF1213, and K. C. Wong Magna Fund in Ningbo University
Acoustic project for installation of motor generator group by means of computer simulation
Ferreira, Jose C.; Zannin, Paulo T.
2001-05-01
This work presents an acoustical project for the installation of a motor generator group of electricity in a hotel by means of computer modeling. The noise levels at the site have been obtained without the motor generator group, and via the computer modeling it has been deduced how these levels would be after the installation of the equipment. A possible solution to mitigate the noise impact the equipment would cause on the neighborhood has been indicated, and it has been predicted how the impact would be reduced after the implantation of this solution.
Nilles, Hans Peter [Bonn Univ. (Germany). Bethe Center for Theoretical Physics; Bonn Univ. (Germany). Physikalisches Inst.; Ratz, Michael [Technische Univ. Muenchen, Garching (Germany). Physik-Department; Vaudrevange, Patrick K.S. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2012-04-15
Discrete (family) symmetries might play an important role in models of elementary particle physics. We discuss the origin of such symmetries in the framework of consistent ultraviolet completions of the standard model in field and string theory. The symmetries can arise due to special geometrical properties of extra compact dimensions and the localization of fields in this geometrical landscape. We also comment on anomaly constraints for discrete symmetries.
Neutrinos and flavor symmetries
Tanimoto, Morimitsu
2015-07-01
We discuss the recent progress of flavor models with the non-Abelian discrete symmetry in the lepton sector focusing on the θ13 and CP violating phase. In both direct approach and indirect approach of the flavor symmetry, the non-vanishing θ13 is predictable. The flavor symmetry with the generalised CP symmetry can also predicts the CP violating phase. We show the phenomenological analyses of neutrino mixing for the typical flavor models.
Neutrinos and flavor symmetries
Tanimoto, Morimitsu
2015-07-15
We discuss the recent progress of flavor models with the non-Abelian discrete symmetry in the lepton sector focusing on the θ{sub 13} and CP violating phase. In both direct approach and indirect approach of the flavor symmetry, the non-vanishing θ{sub 13} is predictable. The flavor symmetry with the generalised CP symmetry can also predicts the CP violating phase. We show the phenomenological analyses of neutrino mixing for the typical flavor models.
On the origin of neutrino flavour symmetry
King, Stephen F
2009-01-01
We study classes of models which are based on some discrete family symmetry which is completely broken such that the observed neutrino flavour symmetry emerges indirectly as an accidental symmetry. For such "indirect" models we discuss the D-term flavon vacuum alignments which are required for such an accidental flavour symmetry consistent with tri-bimaximal lepton mixing to emerge. We identify large classes of suitable discrete family symmetries, namely the $\\Delta(3n^2)$ and $\\Delta(6n^2)$ groups, together with other examples such as $Z_7\\rtimes Z_3$. In such indirect models the implementation of the type I see-saw mechanism is straightforward using constrained sequential dominance. However the accidental neutrino flavour symmetry may be easily violated, for example leading to a large reactor angle, while maintaining accurately the tri-bimaximal solar and atmospheric predictions.
Matrix product operators for symmetry-protected topological phases: Gauging and edge theories
Williamson, Dominic J.; Bultinck, Nick; Mariën, Michael; Şahinoǧlu, Mehmet B.; Haegeman, Jutho; Verstraete, Frank
2016-11-01
Projected entangled pair states (PEPS) provide a natural ansatz for the ground states of gapped, local Hamiltonians in which global characteristics of a quantum state are encoded in properties of local tensors. We develop a framework to describe onsite symmetries, as occurring in systems exhibiting symmetry-protected topological (SPT) quantum order, in terms of virtual symmetries of the local tensors expressed as a set of matrix product operators (MPOs) labeled by distinct group elements. These MPOs describe the possibly anomalous symmetry of the edge theory, whose local degrees of freedom are concretely identified in a PEPS. A classification of SPT phases is obtained by studying the obstructions to continuously deforming one set of MPOs into another, recovering the results derived for fixed-point models [Chen et al., Phys. Rev. B 87, 155114 (2013), 10.1103/PhysRevB.87.155114]. Our formalism accommodates perturbations away from fixed-point models, opening the possibility of studying phase transitions between different SPT phases. We also demonstrate that applying the recently developed quantum state gauging procedure to a SPT PEPS yields a PEPS with topological order determined by the initial symmetry MPOs. The MPO framework thus unifies the different approaches to classifying SPT phases, via fixed-point models, boundary anomalies, or gauging the symmetry, into the single problem of classifying inequivalent sets of matrix product operator symmetries that are defined purely in terms of a PEPS.
Maniplexes: Part 1: Maps, Polytopes, Symmetry and Operators
Steve Wilson
2012-04-01
Full Text Available This paper introduces the idea of a maniplex, a common generalization of map and of polytope. The paper then discusses operators, orientability, symmetry and the action of the symmetry group.
Geometric Approach to Lie Symmetry of Discrete Time Toda Equation
JIA Xiao-Yu; WANG Na
2009-01-01
By using the extended Harrison and Estabrook geometric approach,we investigate the Lie symmetry of discrete time Toda equation from the geometric point of view.Its one-dimensional continuous symmetry group is presented.
Lie Point Symmetries of Differential-Difference Equations
DING Wei; TANG Xiao-Yan
2004-01-01
In this paper, the classical Lie group approach is extended to find some Lie point symmetries of differentialdifference equations. It reveals that the obtained Lie point symmetries can constitute a Kac-Moody-Virasoro algebra.
On Gauging Symmetry of Modular Categories
Cui, Shawn X.; Galindo, César; Plavnik, Julia Yael; Wang, Zhenghan
2016-05-01
Topological order of a topological phase of matter in two spacial dimensions is encoded by a unitary modular (tensor) category (UMC). A group symmetry of the topological phase induces a group symmetry of its corresponding UMC. Gauging is a well-known theoretical tool to promote a global symmetry to a local gauge symmetry. We give a mathematical formulation of gauging in terms of higher category formalism. Roughly, given a UMC with a symmetry group G, gauging is a 2-step process: first extend the UMC to a G-crossed braided fusion category and then take the equivariantization of the resulting category. Gauging can tell whether or not two enriched topological phases of matter are different, and also provides a way to construct new UMCs out of old ones. We derive a formula for the {H^4} -obstruction, prove some properties of gauging, and carry out gauging for two concrete examples.
On Gauging Symmetry of Modular Categories
Cui, Shawn X.; Galindo, César; Plavnik, Julia Yael; Wang, Zhenghan
2016-12-01
Topological order of a topological phase of matter in two spacial dimensions is encoded by a unitary modular (tensor) category (UMC). A group symmetry of the topological phase induces a group symmetry of its corresponding UMC. Gauging is a well-known theoretical tool to promote a global symmetry to a local gauge symmetry. We give a mathematical formulation of gauging in terms of higher category formalism. Roughly, given a UMC with a symmetry group G, gauging is a 2-step process: first extend the UMC to a G-crossed braided fusion category and then take the equivariantization of the resulting category. Gauging can tell whether or not two enriched topological phases of matter are different, and also provides a way to construct new UMCs out of old ones. We derive a formula for the {H^4}-obstruction, prove some properties of gauging, and carry out gauging for two concrete examples.
Polynomial Graphs and Symmetry
Goehle, Geoff; Kobayashi, Mitsuo
2013-01-01
Most quadratic functions are not even, but every parabola has symmetry with respect to some vertical line. Similarly, every cubic has rotational symmetry with respect to some point, though most cubics are not odd. We show that every polynomial has at most one point of symmetry and give conditions under which the polynomial has rotational or…
Polynomial Graphs and Symmetry
Goehle, Geoff; Kobayashi, Mitsuo
2013-01-01
Most quadratic functions are not even, but every parabola has symmetry with respect to some vertical line. Similarly, every cubic has rotational symmetry with respect to some point, though most cubics are not odd. We show that every polynomial has at most one point of symmetry and give conditions under which the polynomial has rotational or…
Chiral symmetry and chiral-symmetry breaking
Peskin, M.E.
1982-12-01
These lectures concern the dynamics of fermions in strong interaction with gauge fields. Systems of fermions coupled by gauge forces have a very rich structure of global symmetries, which are called chiral symmetries. These lectures will focus on the realization of chiral symmetries and the causes and consequences of thier spontaneous breaking. A brief introduction to the basic formalism and concepts of chiral symmetry breaking is given, then some explicit calculations of chiral symmetry breaking in gauge theories are given, treating first parity-invariant and then chiral models. These calculations are meant to be illustrative rather than accurate; they make use of unjustified mathematical approximations which serve to make the physics more clear. Some formal constraints on chiral symmetry breaking are discussed which illuminate and extend the results of our more explicit analysis. Finally, a brief review of the phenomenological theory of chiral symmetry breaking is presented, and some applications of this theory to problems in weak-interaction physics are discussed. (WHK)
Dynamical gauge symmetry breaking on the lattice
Farakos, K.; Koutsoumbas, G.; Zoupanos, G. (National Research Centre for the Physical Sciences Democritos, Athens (Greece))
1990-10-11
We study, using lattice techniques, the dynamical symmetry breaking of a three-dimensional theory that mimics the electroweak sector of the standard model. We show that in the strong coupling limit of a QCD-like theory the fermion condensates which are produced induce dynamical symmetry breaking of the sector corresponding to the electroweak gauge group. (orig.).
de Leeuw, Marius; Moriyama, Sanefumi; Regelskis, Vidas; Torrielli, Alessandro
2012-01-01
We discuss special quantum group (secret) symmetries of the integrable system associated to the AdS/CFT correspondence. These symmetries have by now been observed in a variety of forms, including the spectral problem, the boundary scattering problem, n-point amplitudes, the pure-spinor formulation and quantum affine deformations.
Hidden flavor symmetries of SO(10 GUT
Borut Bajc
2016-08-01
Full Text Available The Yukawa interactions of the SO(10 GUT with fermions in 16-plets (as well as with singlets have certain intrinsic (“built-in” symmetries which do not depend on the model parameters. Thus, the symmetric Yukawa interactions of the 10 and 126 dimensional Higgses have intrinsic discrete Z2×Z2 symmetries, while the antisymmetric Yukawa interactions of the 120 dimensional Higgs have a continuous SU(2 symmetry. The couplings of SO(10 singlet fermions with fermionic 16-plets have U(13 symmetry. We consider a possibility that some elements of these intrinsic symmetries are the residual symmetries, which originate from the (spontaneous breaking of a larger symmetry group Gf. Such an embedding leads to the determination of certain elements of the relative mixing matrix U between the matrices of Yukawa couplings Y10, Y126, Y120, and consequently, to restrictions of masses and mixings of quarks and leptons. We explore the consequences of such embedding using the symmetry group conditions. We show how unitarity emerges from group properties and obtain the conditions it imposes on the parameters of embedding. We find that in some cases the predicted values of elements of U are compatible with the existing data fits. In the supersymmetric version of SO(10 such results are renormalization group invariant.
Hidden flavor symmetries of SO(10) GUT
Bajc, Borut; Smirnov, Alexei Yu.
2016-08-01
The Yukawa interactions of the SO(10) GUT with fermions in 16-plets (as well as with singlets) have certain intrinsic ("built-in") symmetries which do not depend on the model parameters. Thus, the symmetric Yukawa interactions of the 10 and 126 dimensional Higgses have intrinsic discrete Z2 ×Z2 symmetries, while the antisymmetric Yukawa interactions of the 120 dimensional Higgs have a continuous SU(2) symmetry. The couplings of SO(10) singlet fermions with fermionic 16-plets have U(1) 3 symmetry. We consider a possibility that some elements of these intrinsic symmetries are the residual symmetries, which originate from the (spontaneous) breaking of a larger symmetry group Gf. Such an embedding leads to the determination of certain elements of the relative mixing matrix U between the matrices of Yukawa couplings Y10, Y126, Y120, and consequently, to restrictions of masses and mixings of quarks and leptons. We explore the consequences of such embedding using the symmetry group conditions. We show how unitarity emerges from group properties and obtain the conditions it imposes on the parameters of embedding. We find that in some cases the predicted values of elements of U are compatible with the existing data fits. In the supersymmetric version of SO(10) such results are renormalization group invariant.
Cheng, Rebecca Wing-yi; Lam, Shui-fong; Chan, Joanne Chung-yan
2008-06-01
There has been an ongoing debate about the inconsistent effects of heterogeneous ability grouping on students in small group work such as project-based learning. The present research investigated the roles of group heterogeneity and processes in project-based learning. At the student level, we examined the interaction effect between students' within-group achievement and group processes on their self- and collective efficacy. At the group level, we examined how group heterogeneity was associated with the average self- and collective efficacy reported by the groups. The participants were 1,921 Hong Kong secondary students in 367 project-based learning groups. Student achievement was determined by school examination marks. Group processes, self-efficacy and collective efficacy were measured by a student-report questionnaire. Hierarchical linear modelling was used to analyse the nested data. When individual students in each group were taken as the unit of analysis, results indicated an interaction effect of group processes and students' within-group achievement on the discrepancy between collective- and self-efficacy. When compared with low achievers, high achievers reported lower collective efficacy than self-efficacy when group processes were of low quality. However, both low and high achievers reported higher collective efficacy than self-efficacy when group processes were of high quality. With 367 groups taken as the unit of analysis, the results showed that group heterogeneity, group gender composition and group size were not related to the discrepancy between collective- and self-efficacy reported by the students. Group heterogeneity was not a determinant factor in students' learning efficacy. Instead, the quality of group processes played a pivotal role because both high and low achievers were able to benefit when group processes were of high quality.
Klock, P.; Evans, D.
1979-01-01
The Executive Summary and Proceedings of the Working Group Meeting was analyzed to identify specific projects appropriate for Distribution Automation and Control DAC RD&D. Specific projects that should be undertaken in the DAC RD&D program were recommended. The projects are presented under broad categories of work selected based on ESC's interpretation of the results of the Working Group Meeting. Some of the projects are noted as utility industry projects. The ESC recommendations regarding program management are presented. Utility versus Government management responsibilities are noted.
Applications of chiral symmetry
Pisarski, R.D.
1995-03-01
The author discusses several topics in the applications of chiral symmetry at nonzero temperature. First, where does the rho go? The answer: up. The restoration of chiral symmetry at a temperature T{sub {chi}} implies that the {rho} and a{sub 1} vector mesons are degenerate in mass. In a gauged linear sigma model the {rho} mass increases with temperature, m{sub {rho}}(T{sub {chi}}) > m{sub {rho}}(0). The author conjectures that at T{sub {chi}} the thermal {rho} - a{sub 1}, peak is relatively high, at about {approximately}1 GeV, with a width approximately that at zero temperature (up to standard kinematic factors). The {omega} meson also increases in mass, nearly degenerate with the {rho}, but its width grows dramatically with temperature, increasing to at least {approximately}100 MeV by T{sub {chi}}. The author also stresses how utterly remarkable the principle of vector meson dominance is, when viewed from the modern perspective of the renormalization group. Secondly, he discusses the possible appearance of disoriented chiral condensates from {open_quotes}quenched{close_quotes} heavy ion collisions. It appears difficult to obtain large domains of disoriented chiral condensates in the standard two flavor model. This leads to the last topic, which is the phase diagram for QCD with three flavors, and its proximity to the chiral critical point. QCD may be very near this chiral critical point, and one might thereby generated large domains of disoriented chiral condensates.
El Naschie, M.S. [King Abdul Aziz City of Science and Technology, Riyadh (Saudi Arabia)
2007-04-15
The notion of a particle-like state emerging from a symmetry breaking is given five corresponding pictures. We start from a geometrical picture in two dimensions involving a modular curve constructed using 336 triangles. The same number of building blocks is found again, this time as 336 contact points in the ten dimensional space of super string theory in the context of the largest kissing number of lattice sphere packing. The next corresponding representation is an abstract one pertinent to the order of the simple linear Lie group SL(2, n) in seven dimensions (n = 7) which leads to 336 symmetries. Subsequently a tensorial picture is given using the Riemannian tensor of relativity theory but this time in an eight dimensional space (n = 8) for which the number of independent components is again 336. Finally we use a physical string theory related picture in the 12 dimensions of F theory to find 336 moduli space dimensions representing the instanton cells of our theory. It is evident that the five preceding pictures are ten fold interconnected and exchangeable. This additional mental freedom does not only enhance the feeling of understanding, but also facilitates the easy recognition of complex mathematical relations and its connection to the physical concepts.
Hidden Symmetries of Stochastic Models
Boyka Aneva
2007-05-01
Full Text Available In the matrix product states approach to $n$ species diffusion processes the stationary probability distribution is expressed as a matrix product state with respect to a quadratic algebra determined by the dynamics of the process. The quadratic algebra defines a noncommutative space with a $SU_q(n$ quantum group action as its symmetry. Boundary processes amount to the appearance of parameter dependent linear terms in the algebraic relations and lead to a reduction of the $SU_q(n$ symmetry. We argue that the boundary operators of the asymmetric simple exclusion process generate a tridiagonal algebra whose irriducible representations are expressed in terms of the Askey-Wilson polynomials. The Askey-Wilson algebra arises as a symmetry of the boundary problem and allows to solve the model exactly.
Bouwknegt, P G
1995-01-01
W-symmetry is an extension of conformal symmetry in two dimensions. Since its introduction in 1985, W-symmetry has become one of the central notions in the study of two-dimensional conformal field theory. The mathematical structures that underlie W-symmetry are so-called W-algebras, which are higher-spin extensions of the Virasoro algebra. This book contains a collection of papers on W-symmetry, covering the period from 1985 through 1993. Its main focus is the construction of W-algebras and their representation theory. A recurrent theme is the intimate connection between W-algebras and affine
The Influence of tolerance on the Learning Processes in Project Group Work
Wiberg, Merete
This paper presents a moral perspective on group work in higher education by addressing tolerance as a moral value of practice which is intertwined with learning of disciplinary knowledge. The relevance of tolerance among students is discussed in relation to Dewey's ideas of learning through...... of the concept. Project group work is an example of a social setting in an educational context where collaboration between students on the one hand is seen as a way to stimulate processes of learning and on the other hand to strengthen social and moral competences. To be discussed in the paper is how group work...... participation. A link between morality and learning via knowledge production is to be found in the concept of participation due to an understanding of education as constitutive for a democratic society.The aim is to sharpen and discuss the concept of tolerance with respect to both strength and limits...
Operating group as a follow-up strategy of a Nursing Course’s Pedagogical Project
Gabriella Cristine Guerra de Carvalho
2014-09-01
Full Text Available The aim of the study was to monitor and describe the implementation process of the Pedagogical Project of the Nursing Undergraduate Course, at the Catalão Campus of the Federal University of Goiás, from the perspective of professors and students. Qualitative and descriptive study, conducted with thirteen participants, of April, 2010 and June, 2011, in Catalão, GO, Brazil. It was possible to use the operative group as a technology for monitoring and data collection. At the end of each meeting, it was possible to set up a chronicle that was subjected to the thematic content analysis. Two categories emerged and showed as potentiality: the curricular matrix interdisciplinarity, and the students’ immaturity, the conflictive interpersonal relationship between students and professors as their constraints. Working in small groups and the operative group proved to be assertive in the teaching management and conducting research.
The Influence of tolerance on the Learning Processes in Project Group Work
Wiberg, Merete
This paper presents a moral perspective on group work in higher education by addressing tolerance as a moral value of practice which is intertwined with learning of disciplinary knowledge. The relevance of tolerance among students is discussed in relation to Dewey's ideas of learning through...... of the concept. Project group work is an example of a social setting in an educational context where collaboration between students on the one hand is seen as a way to stimulate processes of learning and on the other hand to strengthen social and moral competences. To be discussed in the paper is how group work...... participation. A link between morality and learning via knowledge production is to be found in the concept of participation due to an understanding of education as constitutive for a democratic society.The aim is to sharpen and discuss the concept of tolerance with respect to both strength and limits...
First results from the BOXING (Birmingham-OCIW XMM and IMACS Nearby Groups) project.
Miles, T. A.; Raychaudhury, S.; Mulchaey, J. S.
2004-12-01
We present the first results from the BOXING (Birmingham-OCIW XMM and IMACS Nearby Groups) project, a collaboration between the Observatories of the Carnegie Institute of Washington (OCIW) and the University of Birmingham U.K. to study a sample of 25 galaxy groups (z ˜ 0.06) by means of optical photometry and spectroscopy (du Pont 2.5m; IMACS/Magellan) combined with x-ray observations (XMM). The combination of x-ray with optical data allows us to study the nature of the relationship between the properties of the groups and the galaxies that they contain. In this preliminary study, we present optical luminosity functions, which shows bimodal behavior in the poorer systems, interpreted as result of rapid merging. We also examine the dependence of galaxy morphology on local environment. Once spectroscopic observations are completed, we will be able to study velocity dispersions, star formation and nuclear activity in individual galaxies.
2014-01-01
<正>On October 19,the Shanxi Province Pinglu County Phase I 800,000t/a Aluminum Oxide Project of Shanxi Fusheng Aluminum Co.,Ltd,a subordinate of Hangzhou Jinjiang Group,started operation.This is the fourth Aluminum oxide project constructed and operated by Jinjiang Group.
Planning and managing future space facility projects. [management by objectives and group dynamics
Sieber, J. E.; Wilhelm, J. A.; Tanner, T. A.; Helmreich, R. L.; Burgenbauch, S. F.
1979-01-01
To learn how ground-based personnel of a space project plan and organize their work and how such planning and organizing relate to work outcomes, longitudinal study of the management and execution of the Space Lab Mission Development Test 3 (SMD 3) was performed at NASA Ames Research Center. A view of the problems likely to arise in organizations and some methods of coping with these problems are presented as well as the conclusions and recommendations that pertain strictly to SMD 3 management. Emphasis is placed on the broader context of future space facility projects and additional problems that may be anticipated. A model of management that may be used to facilitate problem solving and communication - management by objectives (MBO) is presented. Some problems of communication and emotion management that MBO does not address directly are considered. Models for promoting mature, constructive and satisfying emotional relationships among group members are discussed.
A model for selecting project team members using multicriteria group decision making
Luciana Hazin Alencar
2010-04-01
Full Text Available Selecting a project team is a complex multi-criteria decision-making problem. For this reason, one appropriate way to tackle such problems involves the use of multi-criteria decision aid methods. However, most of the decisions taken regarding the selection of project teams are made by a group of people. It is this which changes the focus of the problem by moving from one decision-maker (DM to a group of DMs. Analysis needs to be extended in order to consider the preference structure of each individual group member. In this paper, we present a group decision model for project team selection based on a multi-criteria evaluation of the preferences of a client's representatives. It could be applied to any decision problem since it involves a group of decision makers whose preferences diverge little. An application of the model in order to select consultants for a construction project is presented.A seleção da equipe em um projeto é um problema de decisão multicritério. Uma forma apropriada de tratar tais problemas envolve o uso de métodos de apoio multicritério a decisão. Grande parte desses problemas envolve um grupo de decisores. Dessa forma, há uma mudança no foco da decisão de um decisor para um grupo de decisores. A análise deve ser ampliada no intuito de considerar a estrutura de preferência de cada membro do grupo. Nesse artigo, apresentamos um modelo aplicado à seleção de equipe de um projeto baseado na avaliação multicritério das preferências dos representantes do cliente do projeto. Pode ser aplicado a qualquer problema de decisão desde que envolva um grupo de decisores que tenham pequena divergência em relação às suas preferências. Uma aplicação para seleção de parte da equipe de um projeto de construção é apresentada.
Caiozzo, V. J.; Haddad, F.; Lee, S.; Baker, M.; Baldwin, K. M.
2007-01-01
The goal of this project was to examine the effects of artificial gravity (2.5 g) on skeletal muscle strength and key anabolic/catabolic markers known to regulate muscle mass. Two groups of subjects were selected for study: 1) a 21 day-bed rest (BR) control (C) group (N=7); and 2) an AG group (N=8), which was exposed to 21 days of bed-rest plus daily 1 hr exposures to AG (2.5 g). This particular experiment was part of an integrated AG Pilot Project sponsored by NASA/Johnson Space Center. The in vivo torque-velocity relationships of the knee extensors and plantar flexors of the ankle were determined pre and post treatment. Also, pre- and post treatment biopsy samples were obtained from both the vastus lateralis and soleus muscles and were used, in part, for a series of analyses on gene expression (mRNA abundance) of key factors implicated in the anabolic versus catabolic state of the muscle. Post/Pre toque-velocity determinations revealed greater decrements in knee extensor performance in the C versus AG group (P less than 0.04). The plantar flexor muscle group of the AG subjects actually demonstrated a net gain in torque-velocity relationship; whereas, in the C group the overall post/pre responses declined (AG vs C; P less than 0.001). Measurements of muscle fiber cross-sectional area (for both muscles) demonstrated a loss of approx. 20% in the C group while no losses were evident in the AG group. RT-PCR analyses of muscle biopsy specimens demonstrated that markers of growth and cytoskeletal integrity (IGF-1, IGF-1 BP4, mechano growth factor, total RNA, and pro-collagen 3a) were higher in the AG group, whereas catabolic markers (myostatin and atrogen) were elevated in the C group. Importantly, these patterns were seen in both muscles. Based on these observations we conclude that paradigms of AG have the potential to maintain the functional, biochemical, and structural homeostasis of skeletal muscle in the face of chronic unloading states. These findings also
A project by the SIDeMaST Immunopathology Group on cutaneous vasculitis.
Papini, M; Quaglino, P; La Placa, M; Marzano, A V
2015-04-01
Vasculitides are a challenge to the clinician, in terms of both diagnosis and therapy. Multiple classification systems have been implemented and the numerous classification schemes reflect the complexity of establishing a simple classification that could be functional for daily care. Although vasculitis classification has become increasingly elaborated, some areas remain ill defined. Some forms of vasculitis are still difficult to assign to a specific disease entity. Generally accepted operational criteria are available for many vasculitides, but for some entities there are no effective criteria. Moreover, diagnostic criteria for vasculitis with sufficient strength and/or confidence that can be universally accepted are not yet available. The need for diagnostic criteria validated and agreed upon is particularly relevant in the context of cutaneous vasculitis. The project of the SIDeMaST Italian Group of Immunopathology on cutaneous vasculitis is a national prospective observational study designed to develop and validate diagnostic criteria and to improve and validate classification criteria for cutaneous small vessel vasculitis also known as leukocytoclastic vasculitis (CLV). Primary objective of the study will also be that of developing the CUtaneous VAsculitis Severity Index (CUVASI). Secondary objectives of the project will be: 1) definition of the etiological agents that are most frequently associated with CLV; 2) search for possible correlations between causative agent and peculiar clinical and/or histopathological aspects; 3) evaluation of immunofluorescence pattern observed in this specific group of primitive cutaneous vasculitis in order to characterize the diagnostic sensitivity and specificity of this technique; 4) identification of a set of clinical investigations and laboratory tests to be performed for a correct CLV assessment. Actually 15 Italian dermatological clinics are contributing to the project and anticipated recruiting >100 patients with CLV
Hansen, Søren
2004-01-01
The article demonstrates how the supervisor can facilitate development of competencies as an implicit part of supervising study projects.......The article demonstrates how the supervisor can facilitate development of competencies as an implicit part of supervising study projects....
Symmetries of partial differential equations
Gaussier, Hervé; Merker, Joël
2004-01-01
We establish a link between the study of completely integrable systems of partial differential equations and the study of generic submanifolds in C^n. Using the recent developments of Cauchy-Riemann geometry we provide the set of symmetries of such a system with a Lie group structure. Finally we determine the precise upper bound of the dimension of this Lie group for some specific systems of partial differential equations.
Dynamics symmetries of Hamiltonian system on time scales
Peng, Keke, E-mail: pengkeke88@126.com; Luo, Yiping, E-mail: zjstulyp@126.com [Department of Physics, Zhejiang Sci-Tech University, Hangzhou 310018 (China)
2014-04-15
In this paper, the dynamics symmetries of Hamiltonian system on time scales are studied. We study the symmetries and quantities based on the calculation of variation and Lie transformation group. Particular focus lies in: the Noether symmetry leads to the Noether conserved quantity and the Lie symmetry leads to the Noether conserved quantity if the infinitesimal transformations satisfy the structure equation. As the new application of result, at end of the article, we give a simple example of Noether symmetry and Lie symmetry on time scales.
Dynamics symmetries of Hamiltonian system on time scales
Peng, Keke; Luo, Yiping
2014-04-01
In this paper, the dynamics symmetries of Hamiltonian system on time scales are studied. We study the symmetries and quantities based on the calculation of variation and Lie transformation group. Particular focus lies in: the Noether symmetry leads to the Noether conserved quantity and the Lie symmetry leads to the Noether conserved quantity if the infinitesimal transformations satisfy the structure equation. As the new application of result, at end of the article, we give a simple example of Noether symmetry and Lie symmetry on time scales.
Heeck, Julian
2013-04-15
Augmenting the Standard Model by three right-handed neutrinos allows for an anomaly-free gauge group extension G{sub max}=U(1){sub B−L}×U(1){sub L{sub e−L{sub μ}}}×U(1){sub L{sub μ−L{sub τ}}}. Simple U(1) subgroups of G{sub max} can be used to impose structure on the righthanded neutrino mass matrix, which then propagates to the active neutrino mass matrix via the seesaw mechanism. We show how this framework can be used to gauge the approximate lepton-number symmetries behind the normal, inverted, and quasidegenerate neutrino mass spectrum, and also how to generate texture-zeros and vanishing minors in the neutrino mass matrix, leading to testable relations among mixing parameters.
2010-07-01
... teacher in an elementary or secondary school; (3) Is an experienced education administrator responsible... 34 Education 3 2010-07-01 2010-07-01 false Who is eligible to participate in projects funded under the Fulbright-Hays Group Projects Abroad Program? 664.3 Section 664.3 Education Regulations of...
Melissa B. Littlefield
2002-05-01
Full Text Available Blackboard (TM provides social work educators integrated online communication tools that they can employ to facilitate student learning through features such as e-mail, discussion forums, file exchange, virtual classroom, and links to online resources. This study describes students’ experiences using Blackboard (TM to support a group project assignment. The majority of students found it easy to use and useful for the project, and indicated that they would like to use it in other courses. In addition, students gained technical skills as a result of the group project. Students’ group project grades and final course grades were comparable to those in other sections of the same course taught by this investigator. The findings of this study suggest that online technology can be used to facilitate group assignments for MSW students. The benefits include increased efficiency of group functioning and increased accountability of group members. The challenges include technical problems and student resistance to using the technology.
Dommeyer, Curt J.
2007-01-01
This article reports on the use of group and individual diaries to control social loafing on the group project. Although both forms of the diary were designed to prevent social loafing, neither appeared to do so. An unexpected result of the individual diaries is that they appeared to make the majority of the class, namely the "nonloafers," more…
Large neutrino mixing from large discrete symmetries
Neder, Thomas; King, Stephen F.; Stuart, Alexander J. [School of Physics and Astronomy, University of Southampton (United Kingdom)
2013-07-01
Several finite groups that are candidates for a flavor symmetry of leptons are investigated. Promising candidates are amongst others the groups Δ(150) and Δ(600). The group theory of these groups as well as results for the lepton mixing parameters resulting from these groups are presented.
Hidden flavor symmetries of SO(10) GUT
Bajc, Borut
2016-01-01
The Yukawa interactions of the SO(10) GUT with fermions in 16-plets (as well as with singlets) have certain intrinsic ("built-in") symmetries which do not depend on the model parameters. Thus, the symmetric Yukawa interactions of the 10 and 126 dimensional Higgses have intrinsic discrete $Z_2\\times Z_2$ symmetries, while the antisymmetric Yukawa interactions of the 120 dimensional Higgs have a continuous SU(2) symmetry. The couplings of SO(10) singlet fermions with fermionic 16-plets have $U(1)^3$ symmetry. We consider a possibility that some elements of these intrinsic symmetries are the residual symmetries, which originate from the (spontaneous) breaking of a larger symmetry group $G_f$. Such an embedding leads to the determination of certain elements of the relative mixing matrix $U$ between the matrices of Yukawa couplings $Y_{10}$, $Y_{126}$, $Y_{120}$, and consequently, to restrictions of masses and mixings of quarks and leptons. We explore the consequences of such embedding using the symmetry group con...
ON THE NOETHER SYMMETRY AND LIE SYMMETRY OF MECHANICAL SYSTEMS
梅凤翔; 郑改华
2002-01-01
The Noether symmetry is an invariance of Hamilton action under infinitesimal transformations of time and the coordinates. The Lie symmetry is an invariance of the differential equations of motion under the transformations. In this paper, the relation between these two symmetries is proved definitely and firstly for mechanical systems. The results indicate that all the Noether symmetries are Lie symmetries for Lagrangian systems meanwhile a Noether symmetry is a Lie symmetry for the general holonomic or nonholonomic systems provided that some conditions hold.
Affine extensions of non-crystallographic Coxeter groups induced by projection
Dechant, Pierre-Philippe; BÅ`hm, Céline; Twarock, Reidun
2013-09-01
In this paper, we show that affine extensions of non-crystallographic Coxeter groups can be derived via Coxeter-Dynkin diagram foldings and projections of affine extended versions of the root systems E8, D6, and A4. We show that the induced affine extensions of the non-crystallographic groups H4, H3, and H2 correspond to a distinguished subset of those considered in [P.-P. Dechant, C. Bœhm, and R. Twarock, J. Phys. A: Math. Theor. 45, 285202 (2012)]. This class of extensions was motivated by physical applications in icosahedral systems in biology (viruses), physics (quasicrystals), and chemistry (fullerenes). By connecting these here to extensions of E8, D6, and A4, we place them into the broader context of crystallographic lattices such as E8, suggesting their potential for applications in high energy physics, integrable systems, and modular form theory. By inverting the projection, we make the case for admitting different number fields in the Cartan matrix, which could open up enticing possibilities in hyperbolic geometry and rational conformal field theory.
Quantized Response and Topological Magnetic Insulators with Inversion Symmetry
Turner, A.M.; Zhang, Y.; Mong, R.S.K.; Vishwanath, A.
2012-01-01
We study three-dimensional insulators with inversion symmetry in which other point group symmetries, such as time reversal, are generically absent. We find that certain information about such materials’ behavior is determined by just the eigenvalues under inversion symmetry of occupied states at
Quantized Response and Topological Magnetic Insulators with Inversion Symmetry
Turner, A.M.; Zhang, Y.; Mong, R.S.K.; Vishwanath, A.
2012-01-01
We study three-dimensional insulators with inversion symmetry in which other point group symmetries, such as time reversal, are generically absent. We find that certain information about such materials’ behavior is determined by just the eigenvalues under inversion symmetry of occupied states at tim
Leptonic Dirac CP Violation Predictions from Residual Discrete Symmetries
Girardi, I; Stuart, Alexander J; Titov, A V
2016-01-01
Assuming that the observed pattern of 3-neutrino mixing is related to the existence of a (lepton) flavour symmetry, corresponding to a non-Abelian discrete symmetry group $G_f$, and that $G_f$ is broken to specific residual symmetries $G_e$ and $G_\
Anomalous Symmetry Fractionalization and Surface Topological Order
Xie Chen
2015-10-01
Full Text Available In addition to possessing fractional statistics, anyon excitations of a 2D topologically ordered state can realize symmetry in distinct ways, leading to a variety of symmetry-enriched topological (SET phases. While the symmetry fractionalization must be consistent with the fusion and braiding rules of the anyons, not all ostensibly consistent symmetry fractionalizations can be realized in 2D systems. Instead, certain “anomalous” SETs can only occur on the surface of a 3D symmetry-protected topological (SPT phase. In this paper, we describe a procedure for determining whether a SET of a discrete, on-site, unitary symmetry group G is anomalous or not. The basic idea is to gauge the symmetry and expose the anomaly as an obstruction to a consistent topological theory combining both the original anyons and the gauge fluxes. Utilizing a result of Etingof, Nikshych, and Ostrik, we point out that a class of obstructions is captured by the fourth cohomology group H^{4}(G,U(1, which also precisely labels the set of 3D SPT phases, with symmetry group G. An explicit procedure for calculating the cohomology data from a SET is given, with the corresponding physical intuition explained. We thus establish a general bulk-boundary correspondence between the anomalous SET and the 3D bulk SPT whose surface termination realizes it. We illustrate this idea using the chiral spin liquid [U(1_{2}] topological order with a reduced symmetry Z_{2}×Z_{2}⊂SO(3, which can act on the semion quasiparticle in an anomalous way. We construct exactly solved 3D SPT models realizing the anomalous surface terminations and demonstrate that they are nontrivial by computing three-loop braiding statistics. Possible extensions to antiunitary symmetries are also discussed.
The zonal satellite problem. III Symmetries
Mioc V.
2002-01-01
Full Text Available The two-body problem associated with a force field described by a potential of the form U =Sum(k=1,n ak/rk (r = distance between particles, ak = real parameters is resumed from the only standpoint of symmetries. Such symmetries, expressed in Hamiltonian coordinates, or in standard polar coordinates, are recovered for McGehee-type coordinates of both collision-blow-up and infinity-blow-up kind. They form diffeomorphic commutative groups endowed with a Boolean structure. Expressed in Levi-Civita’s coordinates, the problem exhibits a larger group of symmetries, also commutative and presenting a Boolean structure.
Tadpoles and Symmetries in Higgs-Gauge Unification Theories
Quirós, Mariano
2005-01-01
In theories with extra dimensions the Standard Model Higgs fields can be identified with internal components of bulk gauge fields (Higgs-gauge unification). The bulk gauge symmetry protects the Higgs mass from quadratic divergences, but at the fixed points localized tadpoles can be radiatively generated if U(1) subgroups are conserved, making the Higgs mass UV sensitive. We show that a global symmetry, remnant of the internal rotation group after orbifold projection, can prevent the generation of such tadpoles. In particular we consider the classes of orbifold compactifications T^d/Z_N (d even, N>2) and T^d/Z_2 (arbitrary d) and show that in the first case tadpoles are always allowed, while in the second they can appear only for d=2 (six dimensions).
From physical symmetries to emergent gauge symmetries
Barceló, Carlos [Instituto de Astrofísica de Andalucía (IAA-CSIC),Glorieta de la Astronomía, 18008 Granada (Spain); Carballo-Rubio, Raúl [Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía, 18008 Granada (Spain); Laboratory for Quantum Gravity & Strings,Department of Mathematics & Applied Mathematics, University of Cape Town,Private Bag, Rondebosch 7701 (South Africa); Di Filippo, Francesco [Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía, 18008 Granada (Spain); Dipartamento di Scienze Fisiche “E.R. Caianiello”, Università di Salerno,I-84081 Fisciano (Italy); Garay, Luis J. [Departamento de Física Teórica II, Universidad Complutense de Madrid, 28040 Madrid (Spain); Instituto de Estructura de la Materia (IEM-CSIC), Serrano 121, 28006 Madrid (Spain)
2016-10-17
Gauge symmetries indicate redundancies in the description of the relevant degrees of freedom of a given field theory and restrict the nature of observable quantities. One of the problems faced by emergent theories of relativistic fields is to understand how gauge symmetries can show up in systems that contain no trace of these symmetries at a more fundamental level. In this paper we start a systematic study aimed to establish a satisfactory mathematical and physical picture of this issue, dealing first with abelian field theories. We discuss how the trivialization, due to the decoupling and lack of excitation of some degrees of freedom, of the Noether currents associated with physical symmetries leads to emergent gauge symmetries in specific situations. An example of a relativistic field theory of a vector field is worked out in detail in order to make explicit how this mechanism works and to clarify the physics behind it. The interplay of these ideas with well-known results of importance to the emergent gravity program, such as the Weinberg-Witten theorem, are discussed.
From physical symmetries to emergent gauge symmetries
Barceló, Carlos; Carballo-Rubio, Raúl; Di Filippo, Francesco; Garay, Luis J.
2016-10-01
Gauge symmetries indicate redundancies in the description of the relevant degrees of freedom of a given field theory and restrict the nature of observable quantities. One of the problems faced by emergent theories of relativistic fields is to understand how gauge symmetries can show up in systems that contain no trace of these symmetries at a more fundamental level. In this paper we start a systematic study aimed to establish a satisfactory mathematical and physical picture of this issue, dealing first with abelian field theories. We discuss how the trivialization, due to the decoupling and lack of excitation of some degrees of freedom, of the Noether currents associated with physical symmetries leads to emergent gauge symmetries in specific situations. An example of a relativistic field theory of a vector field is worked out in detail in order to make explicit how this mechanism works and to clarify the physics behind it. The interplay of these ideas with well-known results of importance to the emergent gravity program, such as the Weinberg-Witten theorem, are discussed.
From physical symmetries to emergent gauge symmetries
Barceló, Carlos; Di Filippo, Francesco; Garay, Luis J
2016-01-01
Gauge symmetries indicate redundancies in the description of the relevant degrees of freedom of a given field theory and restrict the nature of observable quantities. One of the problems faced by emergent theories of relativistic fields is to understand how gauge symmetries can show up in systems that contain no trace of these symmetries at a more fundamental level. In this paper we start a systematic study aimed to establish a satisfactory mathematical and physical picture of this issue, dealing first with abelian field theories. We discuss how the trivialization, due to the decoupling and lack of excitation of some degrees of freedom, of the Noether currents associated with physical symmetries leads to emergent gauge symmetries in specific situations. An example of a relativistic field theory of a vector field is worked out in detail in order to make explicit how this mechanism works and to clarify the physics behind it. The interplay of these ideas with well-known results of importance to the emergent grav...
Optimization leads to symmetry
Chenghong WANG; Yuqian GUO; Daizhan CHENG
2004-01-01
The science of complexity studies the behavior and properties of complex systems in nature and human society.Particular interest has been put on their certain simple common properties.Symmetry is one of such properties.Symmetric phenomena can be found in many complex systems.The purpose of this paper is to reveal the internal reason of the symmetry.Using some physical systems and geometric objects,the paper shows that many symmetries are caused by optimization under certain criteria.It has also been revealed that an evolutional process may lead to symmetry.
Symmetries in atmospheric sciences
Bihlo, Alexander
2009-01-01
Selected applications of symmetry methods in the atmospheric sciences are reviewed briefly. In particular, focus is put on the utilisation of the classical Lie symmetry approach to derive classes of exact solutions from atmospheric models. This is illustrated with the barotropic vorticity equation. Moreover, the possibility for construction of partially-invariant solutions is discussed for this model. A further point is a discussion of using symmetries for relating different classes of differential equations. This is illustrated with the spherical and the potential vorticity equation. Finally, discrete symmetries are used to derive the minimal finite-mode version of the vorticity equation first discussed by E. Lorenz (1960) in a sound mathematical fashion.
Applications of Symmetry Methods to the Theory of Plasma Physics
Giampaolo Cicogna; Francesco Ceccherini; Francesco Pegoraro
2006-01-01
The theory of plasma physics offers a number of nontrivial examples of partial differential equations, which can be successfully treated with symmetry methods. We propose three different examples which may illustrate the reciprocal advantage of this "interaction" between plasma physics and symmetry techniques. The examples include, in particular, the complete symmetry analysis of system of two PDE's, with the determination of some conditional and partial symmetries, the construction of group-...
S4 as a natural flavor symmetry for lepton mixing
Bazzocchi, Federica
2008-01-01
Group theoretical motivations seem to indicate the discrete symmetry S4 as the minimal flavour symmetry compatible with tribimaximal neutrino mixing. We prove in a model independent way that indeed S4 can realize exact TriBimaximal mixing through different symmetry breaking patterns. We present two models in which lepton TriBimaximal mixing is realized in different ways and for each one we discuss the superpotential that leads to the correct breaking of the flavor symmetry.
Ermakov's Superintegrable Toy and Nonlocal Symmetries
Leach, P. G. L.; Karasu Kalkanli, A.; Nucci, M. C.; Andriopoulos, K.
2005-11-01
We investigate the symmetry properties of a pair of Ermakov equations. The system is superintegrable and yet possesses only three Lie point symmetries with the algebra sl(2, R). The number of point symmetries is insufficient and the algebra unsuitable for the complete specification of the system. We use the method of reduction of order to reduce the nonlinear fourth-order system to a third-order system comprising a linear second-order equation and a conservation law. We obtain the representation of the complete symmetry group from this system. Four of the required symmetries are nonlocal and the algebra is the direct sum of a one-dimensional Abelian algebra with the semidirect sum of a two-dimensional solvable algebra with a two-dimensional Abelian algebra. The problem illustrates the difficulties which can arise in very elementary systems. Our treatment demonstrates the existence of possible routes to overcome these problems in a systematic fashion.
Ermakov's Superintegrable Toy and Nonlocal Symmetries
P.G.L. Leach
2005-11-01
Full Text Available We investigate the symmetry properties of a pair of Ermakov equations. The system is superintegrable and yet possesses only three Lie point symmetries with the algebra sl(2, R. The number of point symmetries is insufficient and the algebra unsuitable for the complete specification of the system. We use the method of reduction of order to reduce the nonlinear fourth-order system to a third-order system comprising a linear second-order equation and a conservation law. We obtain the representation of the complete symmetry group from this system. Four of the required symmetries are nonlocal and the algebra is the direct sum of a one-dimensional Abelian algebra with the semidirect sum of a two-dimensional solvable algebra with a two-dimensional Abelian algebra. The problem illustrates the difficulties which can arise in very elementary systems. Our treatment demonstrates the existence of possible routes to overcome these problems in a systematic fashion.
Symmetry in critical random Boolean network dynamics
Hossein, Shabnam; Reichl, Matthew D.; Bassler, Kevin E.
2014-04-01
Using Boolean networks as prototypical examples, the role of symmetry in the dynamics of heterogeneous complex systems is explored. We show that symmetry of the dynamics, especially in critical states, is a controlling feature that can be used both to greatly simplify analysis and to characterize different types of dynamics. Symmetry in Boolean networks is found by determining the frequency at which the various Boolean output functions occur. There are classes of functions that consist of Boolean functions that behave similarly. These classes are orbits of the controlling symmetry group. We find that the symmetry that controls the critical random Boolean networks is expressed through the frequency by which output functions are utilized by nodes that remain active on dynamical attractors. This symmetry preserves canalization, a form of network robustness. We compare it to a different symmetry known to control the dynamics of an evolutionary process that allows Boolean networks to organize into a critical state. Our results demonstrate the usefulness and power of using the symmetry of the behavior of the nodes to characterize complex network dynamics, and introduce an alternative approach to the analysis of heterogeneous complex systems.
Symmetry in Critical Random Boolean Networks Dynamics
Bassler, Kevin E.; Hossein, Shabnam
2014-03-01
Using Boolean networks as prototypical examples, the role of symmetry in the dynamics of heterogeneous complex systems is explored. We show that symmetry of the dynamics, especially in critical states, is a controlling feature that can be used to both greatly simplify analysis and to characterize different types of dynamics. Symmetry in Boolean networks is found by determining the frequency at which the various Boolean output functions occur. Classes of functions occur at the same frequency. These classes are orbits of the controlling symmetry group. We find the nature of the symmetry that controls the dynamics of critical random Boolean networks by determining the frequency of output functions utilized by nodes that remain active on dynamical attractors. This symmetry preserves canalization, a form of network robustness. We compare it to a different symmetry known to control the dynamics of an evolutionary process that allows Boolean networks to organize into a critical state. Our results demonstrate the usefulness and power of using symmetry to characterize complex network dynamics, and introduce a novel approach to the analysis of heterogeneous complex systems. This work was supported by the NSF through grants DMR-0908286 and DMR-1206839, and by the AFSOR and DARPA through grant FA9550-12-1-0405.
Symmetry in critical random Boolean network dynamics.
Hossein, Shabnam; Reichl, Matthew D; Bassler, Kevin E
2014-04-01
Using Boolean networks as prototypical examples, the role of symmetry in the dynamics of heterogeneous complex systems is explored. We show that symmetry of the dynamics, especially in critical states, is a controlling feature that can be used both to greatly simplify analysis and to characterize different types of dynamics. Symmetry in Boolean networks is found by determining the frequency at which the various Boolean output functions occur. There are classes of functions that consist of Boolean functions that behave similarly. These classes are orbits of the controlling symmetry group. We find that the symmetry that controls the critical random Boolean networks is expressed through the frequency by which output functions are utilized by nodes that remain active on dynamical attractors. This symmetry preserves canalization, a form of network robustness. We compare it to a different symmetry known to control the dynamics of an evolutionary process that allows Boolean networks to organize into a critical state. Our results demonstrate the usefulness and power of using the symmetry of the behavior of the nodes to characterize complex network dynamics, and introduce an alternative approach to the analysis of heterogeneous complex systems.
Artificial Neural Networks, Symmetries and Differential Evolution
Urfalioglu, Onay
2010-01-01
Neuroevolution is an active and growing research field, especially in times of increasingly parallel computing architectures. Learning methods for Artificial Neural Networks (ANN) can be divided into two groups. Neuroevolution is mainly based on Monte-Carlo techniques and belongs to the group of global search methods, whereas other methods such as backpropagation belong to the group of local search methods. ANN's comprise important symmetry properties, which can influence Monte-Carlo methods. On the other hand, local search methods are generally unaffected by these symmetries. In the literature, dealing with the symmetries is generally reported as being not effective or even yielding inferior results. In this paper, we introduce the so called Minimum Global Optimum Proximity principle derived from theoretical considerations for effective symmetry breaking, applied to offline supervised learning. Using Differential Evolution (DE), which is a popular and robust evolutionary global optimization method, we experi...
Gillard, Steve; White, Rachel; Miller, Steve; Turner, Kati
2015-03-01
The SUN Project is an innovative, open access support group, based in the community, for people experiencing personality disorders, developed in response to UK Department of Health policy advocating improvements in personality disorders services. The aim of this article is to critically explore where and how the theoretically informed model underpinning the SUN Project is reflected in the view and experiences of people attending the project. This article reports an in-depth, qualitative interview-based study employing a critical realist approach. As part of a larger study about self-care and mental health, in-depth qualitative interviews were held with 38 people new to the SUN Project, and again 9 months later. Data were extracted that were relevant to core components of the project model and were subjected to thematic analysis. The critical realist approach was used to move back and forth between empirical data and theory underpinning the SUN project, providing critical insight into the model. Participant accounts were broadly concordant with core components of the SUN Project's underlying model: Open access and self-referral; group therapeutic processes; community-based support; service users as staff. There were some tensions between interviewee accounts and theoretical aspects of the model, notably around the challenges that group processes presented for some individuals. The model underlying the SUN Project is useful in informing good practice in therapeutic, community-based peer support groups for people experiencing personality disorders. Careful consideration should be given to a limited multi-modal approach, providing focused one-to-one support for vulnerable individuals who find it hard to engage in group processes. Facilitated peer support groups based in the community may act as a powerful therapeutic resource for people experiencing personality disorders. Promoting open access and self-referral to support groups may increase feelings of empowerment and
Bertrand FAURE
2008-01-01
Full Text Available This article reports the works of the research’s group on project based learning (PBL methodologies at the technological institute of Tarbes: assessing the specific contribution of PBL compared to traditional instructions and building an enriched measure of learning during the project. It also presents the future developments of these works (evaluation the impact of PBL on student success.
Marina Nikolić
2014-04-01
Full Text Available The aim of the CHANCE project is to develop novel and affordable nutritious foods to optimize the diet and reduce the risk of diet-related diseases among groups at risk of poverty (ROP. This paper describes the methodology used in the two initial steps to accomplish the project’s objective as follows: 1. a literature review of existing data and 2. an identification of ROP groups with which to design and perform the CHANCE nutritional survey, which will supply new data that is useful for formulating the new CHANCE food. Based on the literature review, a low intake of fruit and vegetables, whole grain products, fish, energy, fiber, vitamins B1, B2, B3, B6, B12 and C, folate, calcium, magnesium, iron, potassium and zinc and a high intake of starchy foods, processed meat and sodium were apparent. However, the available data appeared fragmented because of the different methodologies used in the studies. A more global vision of the main nutritional problems that are present among low-income people in Europe is needed, and the first step to achieve this goal is the use of common criteria to define the risk of poverty. The scoring system described here represents novel criteria for defining at-risk-of-poverty groups not only in the CHANCE-participating countries but also all over Europe.
Nikolić, Marina; Glibetić, Maria; Gurinović, Mirjana; Milešević, Jelena; Khokhar, Santosh; Chillo, Stefania; Abaravicius, Jonas Algis; Bordoni, Alessandra; Capozzi, Francesco
2014-01-01
The aim of the CHANCE project is to develop novel and affordable nutritious foods to optimize the diet and reduce the risk of diet-related diseases among groups at risk of poverty (ROP). This paper describes the methodology used in the two initial steps to accomplish the project’s objective as follows: 1. a literature review of existing data and 2. an identification of ROP groups with which to design and perform the CHANCE nutritional survey, which will supply new data that is useful for formulating the new CHANCE food. Based on the literature review, a low intake of fruit and vegetables, whole grain products, fish, energy, fiber, vitamins B1, B2, B3, B6, B12 and C, folate, calcium, magnesium, iron, potassium and zinc and a high intake of starchy foods, processed meat and sodium were apparent. However, the available data appeared fragmented because of the different methodologies used in the studies. A more global vision of the main nutritional problems that are present among low-income people in Europe is needed, and the first step to achieve this goal is the use of common criteria to define the risk of poverty. The scoring system described here represents novel criteria for defining at-risk-of-poverty groups not only in the CHANCE-participating countries but also all over Europe. PMID:24699195
Theo Hug
2010-06-01
Full Text Available Medienereignisse wie auch die Einführung und Verbreitung neuer Medientechnologien und Formate bringen mannigfaltige Wege des „Eintretens von Medien ins Leben“ mit sich. Im Projekt Globale Mediengenerationen (GMG wurden Medienerinnerungen aus der Kindheit im Kontext von Gruppendiskussionen am Beispiel dreier Generationen aus verschiedenen Ländern aller Kontinente untersucht. Dabei wurden medienbezogene Wissensbestände von drei Alterskohorten globaler Generationen analysiert. Der Artikel diskutiert methodologische Aspekte des Projekts und komplexe und selektive Prozesse des Erinnerns vergangener Ereignisse. Er untersucht Gemeinsamkeiten und Unterschiede des GMG-Ansatzes mit dem dokumentarischen Ansatz von Ralf Bohnsack, die beide in der Wissenssoziologie von Karl Mannheim verwurzelt sind. Darüber hinaus wird Medialität als basale methodologische Kategorie in Erwägung gezogen, nicht nur im Hinblick auf die Klärung begrifflicher Grundlagen, sondern auch als inhärente Dimension von Forschungsprozessen. Media events in general and the introduction and divulgence of new media technologies and formats in particular implicate various (new ways of “media entering life.” In the Global Media Generations (GMG research project, articulation of individuals’ memories of childhood experiences with the media was afforded by context of focus groups of three generations in different countries of six continents. In this project media related knowledge segments of different age cohorts have been analyzed and interpreted. The article deals with methodological questions of the project and complex processes of ‘remembering’ past events. It explores commonalities and differences of the GMG approach with Ralf Bohnsack’s documentary approach, both rooted in the sociology of knowledge of Karl Mannheim. Furthermore, mediality is taken into consideration as a basic methodological category, which means that it is perceived not only as subject matter to
Liu, Bingsheng; Huo, Tengfei; Wang, Xueqing; Shen, Qiping; Chen, Yuan
2013-01-01
... loss, thus social costs are formed. The current bid evaluation mechanism has not yet taken social costs into account, while the present bid evaluation model for construction projects has ignored experts' group character and fuzziness...
The APOSTLE project: Local Group kinematic mass constraints and simulation candidate selection
Fattahi, Azadeh; Sawala, Till; Frenk, Carlos S; Oman, Kyle A; Crain, Robert A; Furlong, Michelle; Schaller, Matthieu; Schaye, Joop; Theuns, Tom; Jenkins, Adrian
2015-01-01
We use a large sample of isolated dark matter halo pairs drawn from cosmological N-body simulations to identify candidate systems whose kinematics match that of the Local Group of Galaxies (LG). We find, in agreement with the "timing argument" and earlier work, that the separation and approach velocity of the Milky Way (MW) and Andromeda (M31) galaxies favour a total mass for the pair of ~ 5*10^12 M_sun. A mass this large, however, is difficult to reconcile with the small relative tangential velocity of the pair, as well as with the small deceleration from the Hubble flow observed for the most distant LG members. Halo pairs that match these three criteria have average masses a factor of ~2 times smaller than suggested by the timing argument, but with large dispersion, spanning more than a decade in mass. Guided by these results, we have selected 12 halo pairs with total mass in the range 1.6-3.6 *10^12 M_sun for the APOSTLE project (A Project Of Simulations of The Local Environment), a suite of resimulations ...
Symbolic Detection of Permutation and Parity Symmetries of Evolution Equations
Alghamdi, Moataz
2017-06-18
We introduce a symbolic computational approach to detecting all permutation and parity symmetries in any general evolution equation, and to generating associated invariant polynomials, from given monomials, under the action of these symmetries. Traditionally, discrete point symmetries of differential equations are systemically found by solving complicated nonlinear systems of partial differential equations; in the presence of Lie symmetries, the process can be simplified further. Here, we show how to find parity- and permutation-type discrete symmetries purely based on algebraic calculations. Furthermore, we show that such symmetries always form groups, thereby allowing for the generation of new group-invariant conserved quantities from known conserved quantities. This work also contains an implementation of the said results in Mathematica. In addition, it includes, as a motivation for this work, an investigation of the connection between variational symmetries, described by local Lie groups, and conserved quantities in Hamiltonian systems.
Marchis, Iuliana
2009-01-01
Symmetry is one of the fundamental concepts in Geometry. It is a Mathematical concept, which can be very well connected with Art and Ethnography. The aim of the article is to show how to link the geometrical concept symmetry with interculturality. For this mosaics from different countries are used.
2016-01-01
The Symmetry Festival is a science and art program series, the most important periodic event (see its history) to bring together scientists, artists, educators and practitioners interested in symmetry (its roots, what is behind, applications, etc.), or in the consequences of its absence.
Schaft, A.J. van der
1987-01-01
It is argued that the existence of symmetries may simplify, as in classical mechanics, the solution of optimal control problems. A procedure for obtaining symmetries for the optimal Hamiltonian resulting from the Maximum Principle is given; this avoids the actual calculation of the optimal
Dirac neutrinos from flavor symmetry
Aranda, Alfredo; Morisi, S; Peinado, E; Valle, J W F
2013-01-01
We present a model where Majorana neutrino mass terms are forbidden by the flavor symmetry group Delta(27). Neutrinos are Dirac fermions and their masses arise in the same way as that of the charged fermions, due to very small Yukawa couplings. The model fits current neutrino oscillation data and correlates the octant of the atmospheric angle with the magnitude of the lightest neutrino mass, with maximal mixing excluded for any neutrino mass
Partial Dynamical Symmetry as an Intermediate Symmetry Structure
Leviatan, A
2003-01-01
We introduce the notion of a partial dynamical symmetry for which a prescribed symmetry is neither exact nor completely broken. We survey the different types of partial dynamical symmetries and present empirical examples in each category.
Mei Symmetry and Lie Symmetry of Relativistic Hamiltonian System
FANG Jian-Hui; YAN Xiang-Hong; LI Hong; CHEN Pei-Sheng
2004-01-01
The Mei symmetry and the Lie symmetry of the relativistic Hamiltonian system are studied. The definition and criterion of the Mei symmetry and the Lie symmetry of the relativistic Hamiltonian system are given. The relationship between them is found. The conserved quantities which the Mei symmetry and the Lie symmetry lead to are obtained.An example is given to illustrate the application of the result.
Seyed javad Mosa kassamy
2012-06-01
Full Text Available The aim of this paper is to prioritize projects by a new approach . For prioritizing EFQM projects , self-assessment is conducted by industry experts and then , improve ment projects are determined . For these projects, “prioritizing” is the main problem in organizations. Because of resource constraints, those projects should be selected and implemented that provide most benefits. Selecting the appropriate indicators, such as " quantity of required resources", " impact on stakeholders" and " p robability of project success" can significantly influence selection of projects. These indicators have been considered in the Try-Success matrix. Also, since each project is depend ed on the EFQM’s criteria, the weights of the criteria have been localized . In the designed software of this study, the scoring mechanism is based on Try-Success matrix, and the local weights are determined by Fuzzy-group AHP. In this paper , the application of software in prioritization of projects has been also addressed. T he output of this approach together with software and investigation, are the determined projects that have higher priorities and provide considerable improvement to the industry .
Leviatan, A
2010-01-01
This overview focuses on the notion of partial dynamical symmetry (PDS), for which a prescribed symmetry is obeyed by a subset of solvable eigenstates, but is not shared by the Hamiltonian. General algorithms are presented to identify interactions, of a given order, with such intermediate-symmetry structure. Explicit bosonic and fermionic Hamiltonians with PDS are constructed in the framework of models based on spectrum generating algebras. PDSs of various types are shown to be relevant to nuclear spectroscopy, quantum phase transitions and systems with mixed chaotic and regular dynamics.
Schwichtenberg, Jakob
2015-01-01
This is a textbook that derives the fundamental theories of physics from symmetry. It starts by introducing, in a completely self-contained way, all mathematical tools needed to use symmetry ideas in physics. Thereafter, these tools are put into action and by using symmetry constraints, the fundamental equations of Quantum Mechanics, Quantum Field Theory, Electromagnetism, and Classical Mechanics are derived. As a result, the reader is able to understand the basic assumptions behind, and the connections between the modern theories of physics. The book concludes with first applications of the previously derived equations.
Mambrini, Matthieu; Orús, Román; Poilblanc, Didier
2016-11-01
We elaborate a simple classification scheme of all rank-5 SU(2) spin rotational symmetric tensors according to (i) the onsite physical spin S , (ii) the local Hilbert space V⊗4 of the four virtual (composite) spins attached to each site, and (iii) the irreducible representations of the C4 v point group of the square lattice. We apply our scheme to draw a complete list of all SU(2)-symmetric translationally and rotationally invariant projected entangled pair states (PEPS) with bond dimension D ≤6 . All known SU(2)-symmetric PEPS on the square lattice are recovered and simple generalizations are provided in some cases. More generally, to each of our symmetry class can be associated a (D -1 )-dimensional manifold of spin liquids (potentially) preserving lattice symmetries and defined in terms of D -independent tensors of a given bond dimension D . In addition, generic (low-dimensional) families of PEPS explicitly breaking either (i) particular point-group lattice symmetries (lattice nematics) or (ii) time-reversal symmetry (chiral spin liquids) or (iii) SU(2) spin rotation symmetry down to U(1 ) (spin nematics or Néel antiferromagnets) can also be constructed. We apply this framework to search for new topological chiral spin liquids characterized by well-defined chiral edge modes, as revealed by their entanglement spectrum. In particular, we show how the symmetrization of a double-layer PEPS leads to a chiral topological state with a gapless edge described by a SU (2) 2 Wess-Zumino-Witten model.
Huh, Yeol; Reigeluth, Charles M.; Lee, Dabae
2014-01-01
Based on Bandura's work, the four sources of efficacy shaping were examined in regard to frequency and students' perception of importance in a computer-mediated, project-based high school classroom. In a context of group work where there was no designated leader, groups' collective efficacy was examined if it has any relationship with individual's…
Collaborative Group Learning and Knowledge Building to Address Information Systems Project Failure
Angelo, Raymond
2011-01-01
Approximately half of the information systems (IS) projects implemented each year are considered failures. These failed projects cost billions of dollars annually. Failures can be due to projects being delivered late, over-budget, abandoned after significant time and resource investment, or failing to achieve desired results. More often than not,…
CP symmetry in optical systems
Dana, Brenda; Malomed, Boris A
2015-01-01
We introduce a model of a dual-core optical waveguide with opposite signs of the group-velocity-dispersion (GVD) in the two cores, and a phase-velocity mismatch between them. The coupler is embedded into an active host medium, which provides for the linear coupling of a gain-loss type between the two cores. The same system can be derived, without phenomenological assumptions, by considering the three-wave propagation in a medium with the quadratic nonlinearity, provided that the depletion of the second-harmonic pump is negligible. This linear system offers an optical realization of the charge-parity ($\\mathcal{CP}$) symmetry, while the addition of the intra-core cubic nonlinearity breaks the symmetry. By means of direct simulations and analytical approximations, it is demonstrated that the linear system generates expanding Gaussian states, while the nonlinear one gives rise to broad oscillating solitons, as well as a general family of stable stationary gap solitons.
Lepton mixing and discrete symmetries
Hernandez, D.; Smirnov, A. Yu.
2012-09-01
The pattern of lepton mixing can emerge from breaking a flavor symmetry in different ways in the neutrino and charged lepton Yukawa sectors. In this framework, we derive the model-independent conditions imposed on the mixing matrix by the structure of discrete groups of the von Dyck type which include A4, S4, and A5. We show that, in general, these conditions lead to at least two equations for the mixing parameters (angles and CP phase δ). These constraints, which correspond to unbroken residual symmetries, are consistent with nonzero 13 mixing and deviations from maximal 2-3 mixing. For the simplest case, which leads to an S4 model and reproduces the allowed values of the mixing angles, we predict δ=(90°-120°).
VanderHorst, Veronique G.J.M.; Holstege, Gert
1995-01-01
The nucleus retroambiguus (NRA) projects to distinct brainstem and cervical and thoracic cord motoneuronal cell groups. The present paper describes NRA projections to distinct motoneuronal cell groups in the lumbar enlargement. Lumbosacral injections of wheat germ agglutinin-horseradish peroxidase
VANDERHORST, VGJM; HOLSTEGE, G
1995-01-01
The nucleus retroambiguus (NRA) projects to distinct brainstem and cervical and thoracic cord motoneuronal cell groups. The present paper describes NRA projections to distinct motoneuronal cell groups in the lumbar enlargement. Lumbosacral injections of wheat germ agglutinin-horseradish peroxidase
Applications of Symmetry Methods to the Theory of Plasma Physics
Giampaolo Cicogna
2006-02-01
Full Text Available The theory of plasma physics offers a number of nontrivial examples of partial differential equations, which can be successfully treated with symmetry methods. We propose three different examples which may illustrate the reciprocal advantage of this "interaction" between plasma physics and symmetry techniques. The examples include, in particular, the complete symmetry analysis of system of two PDE's, with the determination of some conditional and partial symmetries, the construction of group-invariant solutions, and the symmetry classification of a nonlinear PDE.
Golubitsky, Martin
2012-04-01
Many gaits of four-legged animals are described by symmetry. For example, when a horse paces it moves both left legs in unison and then both right legs and so on. The motion is described by two symmetries: Interchange front and back legs, and swap left and right legs with a half-period phase shift. Biologists postulate the existence of a central pattern generator (CPG) in the neuronal system that sends periodic signals to the legs. CPGs can be thought of as electrical circuits that produce periodic signals and can be modeled by systems with symmetry. In this lecture we discuss animal gaits; use gait symmetries to construct a simplest CPG architecture that naturally produces quadrupedal gait rhythms; and make several testable predictions about gaits.
Gauge symmetry from decoupling
Wetterich, C., E-mail: c.wetterich@thphys.uni-heidelberg.de
2017-02-15
Gauge symmetries emerge from a redundant description of the effective action for light degrees of freedom after the decoupling of heavy modes. This redundant description avoids the use of explicit constraints in configuration space. For non-linear constraints the gauge symmetries are non-linear. In a quantum field theory setting the gauge symmetries are local and can describe Yang–Mills theories or quantum gravity. We formulate gauge invariant fields that correspond to the non-linear light degrees of freedom. In the context of functional renormalization gauge symmetries can emerge if the flow generates or preserves large mass-like terms for the heavy degrees of freedom. They correspond to a particular form of gauge fixing terms in quantum field theories.
Gauge symmetry from decoupling
C. Wetterich
2017-02-01
Full Text Available Gauge symmetries emerge from a redundant description of the effective action for light degrees of freedom after the decoupling of heavy modes. This redundant description avoids the use of explicit constraints in configuration space. For non-linear constraints the gauge symmetries are non-linear. In a quantum field theory setting the gauge symmetries are local and can describe Yang–Mills theories or quantum gravity. We formulate gauge invariant fields that correspond to the non-linear light degrees of freedom. In the context of functional renormalization gauge symmetries can emerge if the flow generates or preserves large mass-like terms for the heavy degrees of freedom. They correspond to a particular form of gauge fixing terms in quantum field theories.
CPT Symmetry Without Hermiticity
Mannheim, Philip D
2016-01-01
In the literature the $CPT$ theorem has only been established for Hamiltonians that are Hermitian. Here we extend the $CPT$ theorem to quantum field theories with non-Hermitian Hamiltonians. Our derivation is a quite minimal one as it requires only the time independent evolution of scalar products and invariance under complex Lorentz transformations. The first of these requirements does not force the Hamiltonian to be Hermitian. Rather, it forces its eigenvalues to either be real or to appear in complex conjugate pairs, forces the eigenvectors of such conjugate pairs to be conjugates of each other, and forces the Hamiltonian to admit of an antilinear symmetry. The latter requirement then forces this antilinear symmetry to be $CPT$, with Hermiticity of a Hamiltonian thus only being a sufficient condition for $CPT$ symmetry and not a necessary one. $CPT$ symmetry thus has primacy over Hermiticity, and it rather than Hermiticity should be taken as a guiding principle for constructing quantum theories. With confo...
Gauge symmetry from decoupling
Wetterich, C.
2017-02-01
Gauge symmetries emerge from a redundant description of the effective action for light degrees of freedom after the decoupling of heavy modes. This redundant description avoids the use of explicit constraints in configuration space. For non-linear constraints the gauge symmetries are non-linear. In a quantum field theory setting the gauge symmetries are local and can describe Yang-Mills theories or quantum gravity. We formulate gauge invariant fields that correspond to the non-linear light degrees of freedom. In the context of functional renormalization gauge symmetries can emerge if the flow generates or preserves large mass-like terms for the heavy degrees of freedom. They correspond to a particular form of gauge fixing terms in quantum field theories.
Zhou, Chunfang; Kolmos, Anette
2013-01-01
Recent studies regard Problem and Project Based Learning (PBL) as providing a learning environment which fosters both individual and group creativity. This paper focuses on the question: In a PBL environment, how do students perceive the interplay between individual and group creativity...... individual and group creativity: (1) the project as ‘‘an extra member’’ in student groups; (2) tacit modes of collaboration in student groups; and (3) students have both domain-general and domain-specific understandings of creativity. These findings suggest the need for improved approaches to develop......? Empirically, qualitative interviews were carried out with 53 students (12 groups) in Computer Science, Electronic Systems, Architecture and Design, and Medialogy at Aalborg University, Denmark. The data analysis shows that there are three aspects to the influences of a PBL environment on the interplay between...
Zhou, Chunfang; Kolmos, Anette
2013-01-01
Recent studies regard Problem and Project Based Learning (PBL) as providing a learning environment which fosters both individual and group creativity. This paper focuses on the question: In a PBL environment, how do students perceive the interplay between individual and group creativity......? Empirically, qualitative interviews were carried out with 53 students (12 groups) in Computer Science, Electronic Systems, Architecture and Design, and Medialogy at Aalborg University, Denmark. The data analysis shows that there are three aspects to the influences of a PBL environment on the interplay between...... individual and group creativity: (1) the project as ‘‘an extra member’’ in student groups; (2) tacit modes of collaboration in student groups; and (3) students have both domain-general and domain-specific understandings of creativity. These findings suggest the need for improved approaches to develop...
Borrajo, M.; Egido, J.L. [Universidad Autonoma de Madrid, Departamento de Fisica Teorica, Madrid (Spain)
2016-09-15
We present an approach for the calculation of odd nuclei with exact self-consistent blocking and particle number and angular-momentum projection with the finite-range density-dependent Gogny force. As an application we calculate the nucleus {sup 31}Mg at the border of the N = 20 inversion island. We evaluate the ground-state properties, the excited states and the transition probabilities. In general we obtain a good description of the measured observables. (orig.)
Superconductivity and symmetry breaking
Sarasua, L.G., E-mail: sarasua@fisica.edu.uy [Instituto de Fisica, Facultad de Ciencias, Universidad de la Republica, Montevideo (Uruguay)
2012-02-15
In the present work we consider the relation between superconductivity and spontaneous gauge symmetry breaking (SGBS). We show that ODLRO does not require in principle SBGS, even in the presence of particle number fluctuations, by examining exact solutions of a fermionic pairing model. The criteria become equivalent if a symmetry breaking field is allowed, which can be attributed to the interaction with the environment. However, superconducting states without SBGS are not forbidden.
Baldo, M.; Burgio, G. F.
2016-11-01
The nuclear symmetry energy characterizes the variation of the binding energy as the neutron to proton ratio of a nuclear system is varied. This is one of the most important features of nuclear physics in general, since it is just related to the two component nature of the nuclear systems. As such it is one of the most relevant physical parameters that affect the physics of many phenomena and nuclear processes. This review paper presents a survey of the role and relevance of the nuclear symmetry energy in different fields of research and of the accuracy of its determination from the phenomenology and from the microscopic many-body theory. In recent years, a great interest was devoted not only to the Nuclear Matter symmetry energy at saturation density but also to its whole density dependence, which is an essential ingredient for our understanding of many phenomena. We analyze the nuclear symmetry energy in different realms of nuclear physics and astrophysics. In particular we consider the nuclear symmetry energy in relation to nuclear structure, astrophysics of Neutron Stars and supernovae, and heavy ion collision experiments, trying to elucidate the connections of these different fields on the basis of the symmetry energy peculiarities. The interplay between experimental and observational data and theoretical developments is stressed. The expected future developments and improvements are schematically addressed, together with most demanded experimental and theoretical advances for the next few years.
Nonlocal Symmetries and Exact Solutions for PIB Equation
Xin, Xiang-Peng; Miao, Qian; Chen, Yong
2012-09-01
In this paper, the symmetry group of the (2+1)-dimensional Painlevé integrable Burgers (PIB) equations is studied by means of the classical symmetry method. Ignoring the discussion of the infinite-dimensional subalgebra, we construct an optimal system of one-dimensional group invariant solutions. Furthermore, by using the conservation laws of the reduced equations, we obtain nonlocal symmetries and exact solutions of the PIB equations.
Nonlocal Symmetries and Exact Solutions for PIB Equation
辛祥鹏; 苗倩; 陈勇
2012-01-01
In this paper, the symmetry group of the is studied by means of the classical symmetry method （2＋l）-dimensionM Painlevd integrable Burgers （PIB） equations Ignoring the discussion of the infinite-dimensional subalgebra, we construct an optimal system of one-dimensional group invariant solutions. Furthermore, by using the conservation laws of the reduced equations, we obtain nonlocal symmetries and exact solutions of the PIB equations.
Symmetries and Exact Solutions of the Breaking Soliton Equation
陈美; 刘希强
2011-01-01
With the aid of the classical Lie group method and nonclassical Lie group method, we derive the classical Lie point symmetry and the nonclassical Lie point symmetry of （2＋1）-dimensional breaking soliton （BS） equation. Using the symmetries, we find six classical similarity reductions and two nonclassical similarity reductions of the BS equation. Varieties of exact solutions of the BS equation are obtained by solving the reduced equations.
Jiahang Yuan
2017-01-01
Full Text Available In consideration of the interaction among attributes and the influence of decision makers’ risk attitude, this paper proposes an intuitionistic trapezoidal fuzzy aggregation operator based on Choquet integral and prospect theory. With respect to a multiattribute group decision-making problem, the prospect value functions of intuitionistic trapezoidal fuzzy numbers are aggregated by the proposed operator; then a grey relation-projection pursuit dynamic cluster method is developed to obtain the ranking of alternatives; the firefly algorithm is used to optimize the objective function of projection for obtaining the best projection direction of grey correlation projection values, and the grey correlation projection values are evaluated, which are applied to classify, rank, and prefer the alternatives. Finally, an illustrative example is taken in the present study to make the proposed method comprehensible.
Feather, Rebecca A; Carr, Doug E; Reising, Deanna L; Garletts, Derrick M
2016-01-01
Past research indicates that inadequacies in health care delivery create substantial preventable quality issues that can be addressed through improving relationships among clinicians to decrease the negative effects on patient outcomes. The purpose of this article is to describe the implementation of an interprofessional education project with senior nursing and third-year medical students working in teams in a clinical setting. Results include data from focus groups conducted at the conclusion of the project.
Geometrical symmetries of nuclear systems: D(3h) and T(d) symmetries in light nuclei
Bijker, Roelof
2016-01-01
The role of discrete (or point-group) symmetries in alpha-cluster nuclei is discussed in the framework of the algebraic cluster model which describes the relative motion of the alpha-particles. Particular attention is paid to the discrete symmetry of the geometric arrangement of the alpha-particles, and the consequences for the structure of the corresponding rotational bands. The method is applied to study cluster states in the nuclei 12C and 16O. The observed level sequences can be understood in a simple way as a consequence of the underlying discrete symmetry that characterizes the geometrical configuration of the alpha-particles, i.e. an equilateral triangle with D(3h) symmetry for 12C, and a tetrahedron with T(d) symmetry for 16O. The structure of rotational bands provides a fingerprint of the underlying geometrical configuration of alpha-particles.
Permutation Symmetry Determines the Discrete Wigner Function
Zhu, Huangjun
2016-01-01
The Wigner function provides a useful quasiprobability representation of quantum mechanics, with applications in various branches of physics. Many nice properties of the Wigner function are intimately connected with the high symmetry of the underlying operator basis composed of phase point operators: any pair of phase point operators can be transformed to any other pair by a unitary symmetry transformation. We prove that, in the discrete scenario, this permutation symmetry is equivalent to the symmetry group being a unitary 2 design. Such a highly symmetric representation can only appear in odd prime power dimensions besides dimensions 2 and 8. It suffices to single out a unique discrete Wigner function among all possible quasiprobability representations. In the course of our study, we show that this discrete Wigner function is uniquely determined by Clifford covariance, while no Wigner function is Clifford covariant in any even prime power dimension.
Gait Symmetry in Children with Autism
Victoria L. Chester
2012-01-01
Full Text Available Most studies examining gait asymmetry have focused on infants and toddlers and have tended to use subjective methods of evaluating movement. No previous studies have examined gait symmetry in older children with autism using objective motion capture systems. The purpose of this paper was to quantify gait symmetry in children with autism versus age-matched controls. Fourteen children with autism (N=14 and twenty-two (N=22 age, height, and weight-matched controls participated in the study. An eight camera Vicon motion capture system and four Kistler force plates were used to compute temporal-spatial parameters and symmetry indices during walking. Group differences in these measures were tested using MANOVAs. No significant differences between the autism and control group were found for any of the temporal-spatial measures or symmetry indices. Therefore, results suggest that children with autism demonstrate typical symmetry or interlimb movement during gait. Further research is needed to examine the use of different gait inputs to the symmetry indices (e.g., joint angles and moments. A greater awareness of the movement patterns associated with autism may increase our understanding of this disorder and have important implications for treatment planning.
Symmetries, Supersymmetries, and Pairing in Nuclei
Balantekin, A B
2011-01-01
These summer school lectures cover the use of algebraic techniques in various subfields of nuclear physics. After a brief description of groups and algebras, concepts of dynamical symmetry, dynamical supersymmetry, and supersymmetric quantum mechanics are introduced. Appropriate tools such as quasiparticles, quasispin, and Bogoliubov transformations are discussed with an emphasis on group theoretical foundations of these tools. To illustrate these concepts three physics applications are worked out in some detail: i) Pairing in nuclear physics; ii) Subbarrier fusion and associated group transformations; and iii) Symmetries of neutrino mass and of a related neutrino many-body problem.
Kawamura, Yoshiharu
2015-01-01
We study the quantization of systems with local particle-ghost symmetries. The systems contain ordinary particles including gauge bosons and their counterparts obeying different statistics. The particle-ghost symmetry is a kind of fermionic symmetry, different from the space-time supersymmetry and the BRST symmetry. Subsidiary conditions on states guarantee the unitarity of systems.
Discrete flavor symmetries in D-brane models
Marchesano, Fernando; Vázquez-Mercado, Liliana
2013-01-01
We study the presence of discrete flavor symmetries in D-brane models of particle physics. By analyzing the compact extra dimensions of these models one can determine when such symmetries exist both in the context of intersecting and magnetized D-brane constructions. Our approach allows to distinguish between approximate and exact discrete symmetries, and it can be applied to compactification manifolds with continuous isometries or to manifolds that only contain discrete isometries, like Calabi-Yau three-folds. We analyze in detail the class of rigid D-branes models based on a Z_2 x Z'_2 toroidal orientifold, for which the flavor symmetry group is either the dihedral group D_4 or tensor products of it. We construct explicit Pati-Salam examples in which families transform in non-Abelian representations of the flavor symmetry group, constraining Yukawa couplings beyond the effect of massive U(1) D-brane symmetries.
Fuzzy ta/2 symmetries of straight chain conjugate polyene molecules
无
2009-01-01
On the basis of our recent studies on the molecular fuzzy point group symmetry,we further probe into the more complicated planar one-dimensional fuzzy periodic molecules-straight chain conjugate polyene.Except for the fuzzy translation transformation,the space transformation of the fuzzy screw rotation and the glide plane will be referred to.In addition,other fuzzy point symmetry transformation lain in the space transformation is discussed.Usually there is a correlation between the fuzzy symmetry characterization caused by the transition of the point symmetry elements and by certain space symmetry transformation.For the molecular orbital,the irreducible representation component is analyzed besides the membership function of the fuzzy symmetry transformation.Also,we inquire into the relativity between some molecular property and the fuzzy symmetry characterization.
Symmetry Analysis and Exact Solutions of (2+1)-Dimensional Sawada-Kotera Equation
YU Jian-Ping; ZHI Hong-Yan; SUN Yong-Li; ZHANG Hong-Qing
2008-01-01
Based on the symbolic computation system Maple, the infinite-dimensional symmetry group of the (2+1)-dimensional Sawada Kotera equation is found by the classical Lie group method and the characterization of the group properties is given. The symmetry groups are used to perform the symmetry reduction. Moreover, with Lou's direct method that is based on Lax pairs, we obtain the symmetry transformations of the Sawada Kotera and Konopelchenko Dubrovsky equations, respectively.
Group Creativity Development by Solving Real-life Project in Engineering Education
Zhou, Chunfang; Kolmos, Anette; Du, Xiangyun
2011-01-01
In recent years, problem and project based learning (PBL) has been employed by a growing number of educational institutions to foster creative engineers. Among the diverse pedagogical practices of PBL, there has been an emergence of real-life project for students. Based on literature of creativit...
Invariants of broken discrete symmetries
Kalozoumis, P; Diakonos, F K; Schmelcher, P
2014-01-01
The parity and Bloch theorems are generalized to the case of broken global symmetry. Local inversion or translation symmetries are shown to yield invariant currents that characterize wave propagation. These currents map the wave function from an arbitrary spatial domain to any symmetry-related domain. Our approach addresses any combination of local symmetries, thus applying in particular to acoustic, optical and matter waves. Nonvanishing values of the invariant currents provide a systematic pathway to the breaking of discrete global symmetries.
Movement Symmetries and the Mammalian Vestibular System
McCollum, Gin; Boyle, Richard
2000-03-01
Unity of movement requires vertebrates to have an ability to symmetrize along the midline. For example, human erect stance involves symmetry with respect to gravity. The mammalian vestibular system provides a mechanism for maintaining symmetries, which is also open to influence and adaptation by the rest of the organism. The vestibular system includes the inner ear endorgans and central nuclei, along with projections to oculomotor, cerebellar, thalamic, and spinal motor centers. The vestibular endorgans - the semicircular canals and the otoliths - use sensory hairs to register inertia. The vestibular endorgans are right-left symmetric and the semicircular canals form an approximately orthogonal coordinate system for angular motion. Primary afferent axons project from the endorgans to the vestibular nuclei (and a few other places). The vestibular nuclei integrate vestibular, visual, and somatosensory signals, along with a proposed copy of the voluntary motor command and signals from other central structures. The relationship between the canals and the otoliths gives rise to symmetries among neurons, in the organization among the several vestibular nuclei, and in the projections from the vestibular nuclei. These symmetries organize the space of body movements so that functional relationships are maintained in spite of the many free variables of body movement. They also provide a foundation for adaptive reinterpretation of the relationship between canal and otolith signals, for example in freefall.
Using Group Drawings Activities to Facilitate the Understanding of Systemic Aspects of Projects
Arantes do Amaral, João Alberto; Hess, Aurélio; Gonçalves, Paulo
2017-01-01
) Making drawings in groups promotes knowledge sharing among team members; 3) Making drawings in group fosters creativity and communication between students; 4) Drawing in groups reduces the students’ boredom, makes the lecture more dynamic and interesting; 5) Drawing in groups reinforces bonds between...... students. Our systems analysis suggests that group drawing improves student participation in classroom activities, strengthens bonds between students, and enhances learning....
SU(5) symmetry of spdfg interacting boson model
LI; Jingsheng(李京生); LIU; Yuxin(刘玉鑫); GAO; Peng(高鹏)
2003-01-01
The extended interacting boson model with s-, p-, d-, f- and g-bosons included (spdfg IBM)is investigated. The algebraic structure including the generators, the Casimir operators of the groups at the SU(5) dynamical symmetry and the branching rules of the irreducible representation reductions along the group chain are obtained. The typical energy spectrum of the symmetry is given.
Baldo, M
2016-01-01
The nuclear symmetry energy characterizes the variation of the binding energy as the neutron to proton ratio of a nuclear system is varied. This is one of the most important features of nuclear physics in general, since it is just related to the two component nature of the nuclear systems. As such it is one of the most relevant physical parameters that affect the physics of many phenomena and nuclear processes. This review paper presents a survey of the role and relevance of the nuclear symmetry energy in different fields of research and of the accuracy of its determination from the phenomenology and from the microscopic many-body theory. In recent years, a great interest was devoted not only to the Nuclear Matter symmetry energy at saturation density but also to its whole density dependence, which is an essential ingredient for our understanding of many phenomena. We analyze the nuclear symmetry energy in different realms of nuclear physics and astrophysics. In particular we consider the nuclear symmetry ene...
Joshipura, A.S. [Physical Research Laboratory, Navarangpura, Ahmedabad (India)
2008-01-15
The possible maximal mixing seen in the oscillations of atmospheric neutrinos has led to the postulate of {mu}-{tau} symmetry, which interchanges {nu}{sub {mu}} and {nu}{sub {tau}}. We argue that such a symmetry need not be special to neutrinos but can be extended to all fermions. The assumption that all fermion mass matrices are approximately invariant under the interchange of the second and the third generation fields is shown to be phenomenologically viable and has interesting consequences. In the quark sector, the smallness of V{sub ub} and V{sub cb} can be consequences of this approximate 2-3 symmetry. The same approximate symmetry can simultaneously lead to a large atmospheric mixing angle and can describe the leptonic mixing quite well. We identify two generic scenarios leading to this. One is based on the conventional type-I seesaw mechanism and the other follows from the type-II seesaw model. The latter requires a quasi-degenerate neutrino spectrum for obtaining large atmospheric neutrino mixing in the presence of an approximate {mu}-{tau} symmetry. (orig.)
Operational symmetries basic operations in physics
Saller, Heinrich
2017-01-01
This book describes the endeavour to relate the particle spectrum with representations of operational electroweak spacetime, in analogy to the atomic spectrum as characterizing representations of hyperbolic space. The spectrum of hyperbolic position space explains the properties of the nonrelativistic atoms; the spectrum of electroweak spacetime is hoped to explain those of the basic interactions and elementary particles. In this book, the theory of operational symmetries is developed from the numbers, from Plato’s and Kepler’s symmetries over the simple Lie groups to their applications in nonrelativistic, special relativistic and general relativistic quantum theories with the atomic spectrum for hyperbolic position and, in first attempts, the particle spectrum for electroweak spacetime. The standard model of elementary particles and interactions is characterized by a symmetry group. In general, as initiated by Weyl and stressed by Heisenberg, quantum theory can be built as a theory of operation groups an...
Wigner-Eckart theorem for induced symmetries
Klein, D.J. (Texas A and M University, Galveston (USA). Department of Marine Sciences); Seligman, T.H. (Universidad Nacional Autonoma de Mexico, Mexico City. Inst. de Fisica)
1982-01-01
A unified treatment is given for all group-theoretic problems arising from the evaluation of matrix elements involving operators and states of induced symmetries. To achieve this general treatment two group-theoretic theorems are proven, the first characterizing recoupling coefficients between different symmetry adaptation schemes, and the second making a double coset factorization of a group algebraic matrix basis element. A number of problems previously discussed in the literature, including the conventional Wigner-Eckart theorem and more recent double coset expansions of matrix elements, are realized as special cases in the present treatment. These results entail two new types of recoupling coefficients, namely DC coefficients and 3-symmetry symbols, so that some of their properties are indicated.
2013-04-17
... regions of the world: Africa, East Asia, South Asia, Southeast Asia and the Pacific, the Western... modern foreign languages and area studies for groups of teachers, students, and faculty engaged in a... are required to use the electronic data instrument International Resource Information System (IRIS) to...
The Benefits of Peer-Mentoring in Undergraduate Group Research Projects at The University of Arizona
Hardegree-Ullman, Kevin; McGraw, A. M.; Towner, A. P.; Walker-LaFollette, A.; Robertson, A.; Smith, C.; Turner, J.; Biddle, L. I.; Thompson, R.
2013-06-01
According to the American Institute of Physics, the number of graduate students enrolled in astronomy programs in the US has been steadily increasing in the past 15 years. Research experience is one of the key factors graduate admissions committees look for when choosing students. The University of Arizona Astronomy Club is setting a new precedent in research by having students introduce other students to research. This eases the transition to research projects, and allows students to work in a comfortable setting without the sometimes-overwhelming cognitive disconnect between a professor and their students. The University of Arizona's research projects have many benefits to all students involved. It is well established that people learn a subject best when they have to teach it to others. Students leading the projects learn alongside their peers in a peer-mentoring setting. When project leaders move on in their academic career, other project members can easily take the lead. Students learn how to work in teams, practice effective communication skills, and begin the processes of conducting a full research project, which are essential skills for all budding scientists. These research projects also give students hands-on research experience that supplement and greatly expand on concepts taught in the classroom, and make them more attractive to graduate schools and REU programs.
Gilmore-Perelomov symmetry based approach to photonic lattices
Vergara, Liliana Villanueva
2015-01-01
We revisit electromagnetic field propagation through tight-binding arrays of coupled photonic waveguides, with properties independent of the propagation distance, and recast it as a symmetry problem. We focus our analysis on photonic lattices with underlying symmetries given by three well-known groups, $SU(2)$, $SU(1,1)$ and Heisenberg-Weyl, to show that disperssion relations, normal states and impulse functions can be constructed following a Gilmore-Perelomov coherent state approach. Furthermore, this symmetry based approach can be followed for each an every lattice with an underlying symmetry given by a dynamical group.
History of electroweak symmetry breaking
Kibble, T W B
2015-01-01
In this talk, I recall the history of the development of the unified electroweak theory, incorporating the symmetry-breaking Higgs mechanism, as I saw it from my standpoint as a member of Abdus Salam's group at Imperial College. I start by describing the state of physics in the years after the Second World War, explain how the goal of a unified gauge theory of weak and electromagnetic interactions emerged, the obstacles encountered, in particular the Goldstone theorem, and how they were overcome, followed by a brief account of more recent history, culminating in the historic discovery of the Higgs boson in 2012.
Seeing Science through Symmetry
Gould, L. I.
Seeing Through Symmetry is a course that introduces non-science majors to the pervasive influence of symmetry in science. The concept of symmetry is usedboth as a link between subjects (such as physics, biology, mathematics, music, poetry, and art) and as a method within a subject. This is done through the development and use of interactive multimedia learning environments to stimulate learning. Computer-based labs enable the student to further explore the concept by being gently led from the arts to science. This talk is an update that includes some of the latest changes to the course. Explanations are given on methodology and how a variety of interactive multimedia tools contribute to both the lecture and lab portion of the course (created in 1991 and taught almost every semester since then, including one in Sweden).
Segmentation Using Symmetry Deviation
Hollensen, Christian; Højgaard, L.; Specht, L.
2011-01-01
and evaluate the method. The method uses deformable registration on computed tomography(CT) to find anatomical symmetry deviations of Head & Neck squamous cell carcinoma and combining it with positron emission tomography (PET) images. The method allows the use anatomical and symmetrical information of CT scans...... to improve automatic delineations. Materials: PET/CT scans from 30 patients were used for this study, 20 without cancer in hypopharyngeal volume and 10 with hypharyngeal carcinoma. An head and neck atlas was created from the 20 normal patients. The atlas was created using affine and non-rigid registration...... of the CT-scans into a single atlas. Afterwards the standard deviation of anatomical symmetry for the 20 normal patients was evaluated using non-rigid registration and registered onto the atlas to create an atlas for normal anatomical symmetry deviation. The same non-rigid registration was used on the 10...
Leadership, power and symmetry
Spaten, Ole Michael
2016-01-01
Research publications concerning managers who coach their own employees are barely visible despite its wide- spread use in enterprises (McCarthy & Milner, 2013; Gregory & Levy, 2011; Crabb, 2011). This article focuses on leadership, power and moments of symmetry in the coaching relationship...... session. Thereafter we executed qualitative interviews with both managers and employees. Subsequently, a Thematic Analysis resulted in several themes, including power and moments of symmetry in the coaching relationship. One main conclusion is that the most fruitful coaching was obtained when the coachee...... experienced moments of symmetry and that necessary and sufficient conditions to bring forth such moments include a strong working alliance and the coach being aware of the power at play....
Chanowitz, M.S.
1990-09-01
The Higgs mechanism is reviewed in its most general form, requiring the existence of a new symmetry-breaking force and associated particles, which need not however be Higgs bosons. The first lecture reviews the essential elements of the Higgs mechanism, which suffice to establish low energy theorems for the scattering of longitudinally polarized W and Z gauge bosons. An upper bound on the scale of the symmetry-breaking physics then follows from the low energy theorems and partial wave unitarity. The second lecture reviews particular models, with and without Higgs bosons, paying special attention to how the general features discussed in lecture 1 are realized in each model. The third lecture focuses on the experimental signals of strong WW scattering that can be observed at the SSC above 1 TeV in the WW subenergy, which will allow direct measurement of the strength of the symmetry-breaking force. 52 refs., 10 figs.
Trautmann, Wolfgang; Russotto, Paolo
2016-01-01
The nuclear equation-of-state is a topic of highest current interest in nuclear structure and reactions as well as in astrophysics. In particular, the equation-of-state of asymmetric matter and the symmetry energy representing the difference between the energy densities of neutron matter and of symmetric nuclear matter are not sufficiently well constrained at present. The density dependence of the symmetry energy is conventionally expressed in the form of the slope parameter L describing the derivative with respect to density of the symmetry energy at saturation. Results deduced from nuclear structure and heavy-ion reaction data are distributed around a mean value L=60 MeV. Recent studies have more thoroughly investigated the density range that a particular observable is predominantly sensitive to. Two thirds of the saturation density is a value typical for the information contained in nuclear-structure data. Higher values exceeding saturation have been shown to be probed with meson production and collective ...
Gravitation and Duality Symmetry
D'Andrade, V C; Pereira, J G
2005-01-01
By generalizing the Hodge dual operator to the case of soldered bundles, and working in the context of the teleparallel equivalent of general relativity, an analysis of the duality symmetry in gravitation is performed. Although the basic conclusion is that, at least in the general case, gravitation does not present duality symmetry, there is a particular theory in which this symmetry is present. This theory is a self dual (or anti-self dual) teleparallel gravity in which, owing to the fact that it does not contribute to the gravitational interaction of fermions, the purely tensor part of torsion is assumed to vanish. The corresponding fermionic gravitational interaction is found to be chiral. Since duality is intimately related to renormalizability, this theory will probably be much more amenable to renormalization than teleparallel gravity or general relativity. Although obtained in the context of teleparallel gravity, these results must also be true for general relativity.
Discrete symmetries in the three-Higgs-doublet model
Ivanov, I P
2012-01-01
N-Higgs-doublet models (NHDM) are among the most popular examples of electroweak symmetry breaking mechanisms beyond the Standard Model. Discrete symmetries imposed on the NHDM scalar potential play a pivotal role in shaping the phenomenology of the model, and various symmetry groups have been studied so far. However, in spite of all efforts, the classification of finite Higgs-family symmetry groups realizable in NHDM for any N>2 is still missing. Here, we solve this problem for the three-Higgs-doublet model. Using recently found realizable abelian groups and applying Burnside's theorem and other group-theoretic tools, we find the full list of finite symmetry groups of Higgs-family transformations which are realizable in the scalar sector of 3HDM.