Special Issue "Feature Papers: Symmetry Concepts and Applications"
QuicklinksA special issue of Symmetry (ISSN 2073-8994).
Deadline for manuscript submissions: closed (31 December 2009)
Special Issue Editors
Managing Editor
Dr. Shu-Kun Lin
MDPI, Kandererstrasse 25, CH-4057 Basel, Switzerland
Website: http://www.mdpi.org/lin/
E-Mail:
Interests: molecular recognition; entropy; Gibbs paradox; irreversibility; stability; symmetry; similarity; diversity; diversity preservation; evolution; information theory; thermodynamics; enzyme inhibitors; heterocycles; isotopically-labeled compounds; Lewis acids and bases; quninoxaline N-oxides; photochemistry ESR; aromaticity; protein folding; nature of chemical processes
Assistant Editor
Ms. Laura Simon
MDPI, Kandererstrasse 25, CH-4057 Basel, Switzerland
E-Mail:
Published Papers
Special Issue Information
Submission Information
All papers should be submitted to symmetry@mdpi.org. To be published continuously until the deadline and papers will be listed together at the special issue website.
Submitted papers should not have been published nor be under consideration for publication elsewhere. All papers are refereed through a peer-review process. A guide for authors is available on the Instructions for Authors page. Symmetry is a new international, peer-reviewed, quarterly open access journal published by Molecular Diversity Preservation International.
Open Access publication is free of charge for manuscripts submitted in 2009 and published in the first few issues od Symmetry. English correction fees and/or formatting fees of 250 CHF will be billed in certain cases (250 CHF per paper for those papers that require extensive additional formatting and/or English corrections).
Planned Papers
Type of Paper: Article
Title: Magnetization Dynamics Symmetry in Spin Torque Induced Magnetization Switchin
Author: Xiaobin Wang; E-mail: Xiaobin.Wang@Seagate.com
Abstract: Magnetization dynamics symmetry plays important roles in spin torque induced magnetization switching. Spin moment transferring from polarized itinerant electrons to local magnetization provides a magnetization switching mechanism without using external magnetic field. Besides its importance in fundamental magnetization switching dynamics, spin torque magnetization switching has great application potential for future nanoscale magnetoelectronic devices. The concept of magnetization dynamics symmetry in spin torque induced magnetization switching has not been fully explored. One such example is the widely cited result of spin torque critical switching current in a thin film element strongly depends upon the out of plane demagnetization field. This is quite different from critical switching field for magnetic field induced switching [1]. The fundamental physics reason behind this is the broken rotational symmetry of the spin torque excited thin film magnetization dynamics. Understanding this concept is important for designing magnetic structures with efficient spin torque switching [2]. In this paper we will explore magnetization dynamics symmetry effects on spin torque induced magnetization switching, and its interactions with random fluctuation effects. We will illustrate the consequences of magnetization dynamics symmetry on critical switching current magnitude and thermal stability energy of spin torque induced magnetization switching [3][4], which are the two most important design criterions for nanoscale spin torque magnetic devices. Based upon recently developed concept of logarithmic magnetization susceptibility [5], the interaction between magnetization dynamics symmetry and fluctuations are explored to extract rich information on spin torque induced nonlinear magnetization dynamic processes, and provide paths to control spin torque induced switching under fluctuating environment.
Type of Paper: Article
Title: Invariace Induced Gravity
Authors: Salvatore Capozziello, Mariafelicia De Laurentis; E-mail: capozzie@na.infn.it
Abstract: Starting from a general invariance principle, we discuss the global and the local Poincare' invariance. We show that gravitational interaction comes out as a deformation of the Poincare' group by a conformal-affine group of symmetry transformations. As result a compact, self-contained approach to gravitation is achieved. The resulting Einstein-Cartan theory describes a space endowed with non-vanishing curvature and torsion while the gravitational field equations are Yang-Mills-like ones with the torsion tensor playing the role of the Yang-Mills field strength. The byproduct of this approach is a naturally unified theory of interactions where gravity emerges from invariance principles.
Type of Paper: Article
Title: A Call to Update the Molecular Structural Formula
Author: Joseph Alia; E-mail: aliaj@morris.umn.edu
Affiliation: Division of Science and Mathematics, University of Minnesota, Morris, 600 E 4th St, Morris, MN 56267, USA
Abstract: Since the time of the ancient Greeks atomic theory has sought to establish relationship between geometry of fundamental elements and empirical experience; to this day Platonic solids find relevance in chemistry. The initial sketches of the Lewis diagram had a geometric form but no well established basis in physical theory. Now that quantum concepts have been applied toward the understanding of atoms and molecules for more than eighty years, it is time to update the molecular structural formula. Some suggestions for doing this are made. They involve the integration of the Lewis structure with molecular orbital theory by use of the valency interaction formula, VIF. Examples demonstrate how visually simple pictures based on quantum chemistry describe common bonding types found in molecules.
Type of Paper: Review
Title: Enrich the Symmetry of Maxwell Equations by Exciting Unprecedented Magnetic Responses and their Revolutionary Applications
Author: Ta-Jen Yen; Email: tjyen@mx.nthu.edu.tw
Abstract: To be added soon
Type of Paper: Article
Title: Symmetry Studies for Data Analysis
Authors: Marlos Viana; E-mail: marlos.viana@gmail.com
Affiliation: University of Illinois at Chicago Eye Center
Abstract: The methodology if symmetry studies [1] is centered on the notion of data that are indexed by a finite set of indices or labels upon which certain symmetry relations can be defined. The studies explore the symmetry transformations identified by the set of labels to facilitate the classification, interpretation and statistical analysis of the data indexed by these labels. A finite group acts on the set of labels and determines a linear representation in the data vector space. The resulting factorization of the of data vector space into a sum of invariant subspaces is the consequence of defining a set of algebraically orthogonal projections, one for each irreducible representation of the selected group. The canonical projections are the key elements leading to the explicit calculation and interpretation of the analytical (symmetry-related) properties in the data. Moreover, they provide a formal connection with the statistical theory of the distributions of quadratic forms and the many applications of the underlying statistical methods of decomposition of sum of squares. In this paper, the many applications of the methodology will be described, in connection with the data analytic aspects of Fourier analysis over finite groups.
References: [1] Viana, M. {it Symmetry Studies- An introduction to the analysis of structured data in applications} Cambridge University Press (2008)
Type of Paper: Article
Title: Minimum Phi-Divergence Estimators and Phi-Divergence Test Statistics in Continency Tables with Symmetry Structure: An Overview
Authors: N. Martin 1 and L. Pardo 2
Affiliation: 1 Department of Statistics and O.R. (III) School of Statistics Complutense University of Madrid, 28040 Madrid, Spain
2 Department of Statistics and O.R. (I) Faculty of Mathematics Complutense University of Madrid, 28040 Madrid, Spain; E-mail: lpardo@mat.ucm.es
Abstract: In the last years minimum phi-divergence estimators (M E) and phi-divergence test statistics ( TS) have been introduced as a very good alternative to classical likelihood ratio test and maximum likelihood estimator for di¤erent statistical problems. The main purpose of this paper is to present an overview of the main results presented until now in contingency tables with symmetry structure on the basis of (M E) and ( TS).
Type of Paper: Article
Title: Time-Symmetric Boundary Conditions and Quantum Foundations
Author: K.B. Wharton; E-mail: wharton@science.sjsu.edu
Affiliation: Department of Physics and Astronomy, San Jose State University
Abstract: Despite the widely-held premise that initial boundary conditions (BCs) corresponding to measurements/interactions can fully specify a physical subsystem, taking the "Lagrangian Schema" seriously would imply that both initial and final BCs are required (or more generally, a BC on a closed hypersurface in spacetime). Such a time-symmetric perspective of BCs, as applied to classical fields, leads to interesting parallels with quantum theory. This paper will map out the consequences of this mathematically well-defined (if counter-intuitive) premise, as applied to covariant classical fields. The most notable result is the contextuality of fields constrained in this manner, naturally bypassing the usual arguments against classically-based interpretations of quantum theory.
Title: Asymmetry of Brain and Behaviour in Animals
Authors: Lesley Rogers and Giorgio Vallortigara
E-mail: lrogers@pobox.une.edu.au and giorgio.vallortigara@unitn.it
Type of Paper: Article
Title: Symmetries and Their Applications in Beam Physics
Author: Bela Erdelyi
Affiliations: Department of Physics, Northern Illinois University, DeKalb, IL 60115, USA; Physics Division, Argonne National Laboratory, Argonne, IL 60439, USA; Email erdelyi@anl.gov
Abstract: Beam Physics is a branch of physics that concerns itself with the study of the formation, transport, control and manipulation of streams of particles or waves that undertake a directed energy and information transfer. Besides the fundamental importance of understanding their behavior, they are enabling a vast array of scientific endeavors ranging from the ubiquitous cathode ray tube to the largest man-made scientific instrument in existence, the Large Hadron Collider. In this review, several symmetries and their applications are surveyed, which provide simple conceptual approaches to studies spanning design optimization of charged particle beam optical devices to development of numerical algorithms for long term stability of particle orbits in accelerators.
Type of Paper: Article
Title: Symmetry as a Genuine Dynamic Visual Feature
Authors: Bertrand Zavidovique, Vito DiGesu and Marco Tabacchi; Email: bertrand.zavidovique@u-psud.fr
Type of Paper: Article
Title: On the Selection of a Unique Universe
Author: J. Towe
Affiliation: Department of Physics, The Antelope Valley College, Lancaster, CA 93536, USA; Email: jtowe@avc.edu
Abstract: Although the string landscape embodies a large number of possible cosmologies, a unique universe is selected if admissible super-gravitational states are gauge invariant states within local super-symmetry (analogues of atomic states in F. London’s version of Weyl’s theory). Complementary calibrations result in a galactic hierarchy and fermionic spectrum that parallel observation. Since calibrations are related by one-to-one correspondence, each lepto-quark (flavor-generation) state is related uniquely to an admissible super-gravitational state. Super-gravitational mediators of quark-lepton transitions adjointly represent SU(7), predicting a new lepto-quark state of cumulative mass M~30 GeV/c^2.
Type of Paper: Review
Title: How the Higher Plants Shape the Organ Symmetry
Authors: Marco Fambrini1, Marco Baldanzi2 and Claudio Pugliesi1, *
Affiliations: 1 Dipartimento di Biologia delle Piante Agrarie, Sezione di Genetica, via Matteotti 1B, 56124 Pisa, Italy
2 Dipartimento di Agronomia e Gestione dell Agroecosistema Via S. Michele degli Scalzi 2, 56124 Pisa, Italy
* Corresponding author: Email: cpuglies@agr.unipi.it; Fax +39 50 2216661
Type of Paper: Review
Title: Behind the Looking-Glass: A Review on Human Symmetry Perception
Author: Matthias S. Treder; E-mail: matthias.treder@gmail.com
Affiliation: Berlin Institute of Technology, Machine Learning, Laboratory, Berlin, Germany
Abstract: Human vision is highly proficient in extracting mirror-symmetry from visual input. This review paper compiles empirical and theoretical work on human mirror-symmetry perception with a focus on recent issues in the field, such as spatial filtering, the neural basis of symmetry detection, and its role in the reconstruction of 3D objects. Despite the lack of a mature neural model of symmetry perception, evidence converges towards the idea that it is subserved by a preprocessing stage involving local spatial filters followed by information integration across the visual field in higher-tier areas of visual cortex.
Type of Paper: Review
Title: Symmetry and Asymmetry in Bouncing Gaits
Author: G.A. Cavagna; E-mail: giovanni.cavagna@unimi.it
Affiliation: Dipartimento di Fisiologia Umana, Università degli Studi di Milano, 20133 Milan, Italy
Abstract: In running, hopping and trotting gaits, the centre of mass of the body oscillates each step below and above an equilibrium position where the vertical force on the ground equals body weight. In trotting, low speed running of young humans and all speed running of old humans, the duration of the lower part of the oscillation is about equal to that of the upper part, i.e. the rebound is symmetric. In hopping and high speed running the duration of the upper part exceeds that of the lower part: the rebound is asymmetric. Here we examine the physical and physiological constraints resulting in this on-off-ground symmetry, or asymmetry, of the rebound. Furthermore the average force exerted during the brake when the body decelerates downwards and forwards is greater than that exerted during the push when the body is reaccelerated upwards and forwards. This landing-takeoff asymmetry, which would be nil in an elastic rebound, may help to assess elastic energy storage and recovery during the bouncing step.
Type of Paper: Review
Title: Asymmetry versus Symmetry Decisions in the Vertebrate Embryo
Authors: Raquel Lourenço and Leonor Saúde; E-mail: msaude@fm.ul.pt
Abstract: The design of the vertebrate body plan involves the establishment of asymmetries between the left and the right side of the lateral plate mesoderm, allowing the asymmetric positioning of the internal organs inside the body cavities. At the same time, it is fundamental to promote symmetry within the presomitic mesoderm territory to ensure the symmetric formation of the somites and therefore the correct bilateral allocation of the axial skeleton and skeletal muscles. We will review recent data on how these asymmetry versus symmetry decisions are controlled during embryonic development and discuss the clinical implications of a lack of coordination between these two processes.
Type of Paper: Article
Title: Symmetry in Boolean Satisfiability
Author: Fadi Aloul; Email: faloul@aus.edu
Type of Paper: Review
Title: Applications of the Symmetry Principle in Condensed Matter and Cold Atom Physics
Author: Congjun Wu, Email: wucj@physics.ucsd.edu
Abstract: The symmetry principle plays an important role in various aspects of modern physics, such as analyzing spectra, describing phase transitions, identifying new states of matter, and unifying seemingly different physical phenomena. This review article consists of several applications of this principle in condensed matter and cold atom systems. First, we study the relative spin-orbit symmetry breaking effect in the Fermi surface instability of the Landau-Pomeranchuk type in the F_1^a channel. It provides a new mechanism to generate spin-orbit coupling arising from many-body interactions, in contrast to the conventional mechanism which originates from the single-body effect. After the instability happens, the resulting ordered phase is still isotropic. However, neither spin nor orbit angular momentum is conserved. Instead, their sum, i.e., the total angular momentum, is still a good quantum number. This mechanism is essentially a p-wave generalization of ferromagnetism, and also a particle-hole channel analogy of the %superfluid ^3 He-B phase. Second, we rigorously prove a hidden and {it generic} $SO(5)$ symmetry in spin-3/2 systems with contact interactions, which may be realized in cold atom systems in optical traps or lattices. This symmetry sets up a framework to unify many seemingly unrelated properties of Fermi liquid theory, Cooper pairing structures in such systems. Strong quantum fluctuation effects from this high symmetry are also investigated in strong correlated regimes, such as one-dimensional systems. Third, we study the relation between time-reversal symmetry and the sign problem in fermionic quantum Monte-Carlo (QMC) simulations. We rigorously prove a general criterion dubbed {it T-invariant decomposition} for the absence of the sign problem in the auxiliary field QMC method. Compared to previous works, our method does not require the fermion determinants to be factorizable, and thus can be applied in much wider parameter regions in a large class of models at any filling level and lattice geometry. We apply it to the long standing problem of the two dimensional staggered current phase, which has received extensive attention in high T_c systems. Its existence is conclusively demonstrated for the first time in a bi-layer model.
Type of Paper: Review
Title: Use of Bilateral Symmetry in Human Visual Cognition
Authors: Ryosuke Niimi1; Kazhiko Yokosawa 2
Affiliations: 1 JSPS Research Fellow, Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, JAPAN; niimi@fennel.rcast.u-tokyo.ac.jp
2 Department of Psychology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, JAPAN; yokosawa@L.u-tokyo.ac.jp
Abstract: Bilateral symmetry is a salient visual feature that is easily detected by human vision. Studies in the fields of experimental psychology and cognitive science have revealed that symmetry perception is highly efficient, robust against noise, and gives priority to vertical symmetry. These characteristics are assumed to enable people to better understand the outer world through vision, because many objects are symmetrically shaped (e.g., faces and vehicles). However, symmetric objects rarely form perfectly symmetric images. For example, a face with asymmetric illumination yields an image with asymmetric luminance distribution, and the side profile of a symmetric vehicle is highly asymmetric. How does the visual system detect and use symmetry from these natural images? Our recent findings suggest that symmetry perception helps people determine the orientation of objects rather than locate and recognize objects. Here, we will review many other previous findings on symmetry perception and discuss its functional role in visual cognition.
Type of Paper: Review
Title: Detection and Visualization of Symmetries in Graphs
Author: Seokhee Hong; Email: seokhee.hong@usyd.edu.au
Abstract: Symmetry is a much admired property in visualization. Drawings of graphs in graph theory textbooks are often symmetric, because the symmetry clearly reveals the structure of the graph. In general, to visualize graph with symmetries, We need the following two steps: the first step is to detect symmetries in an abstract graph; and the second step is to display the symmetries in a visualization of the graph. Note that symmetries of graphs is closely related to automorphisms of graphs. The study on symmetric graph drawing has made a great progress during the last decade. In this survey, we review both the fundamental results and recent progress In the field of symmetric graph drawing.
Tape of Paper: Article
Title: Future Symmeries
Author: Bernd Schmeikal
Abstract: I want to show you the logic emerging once we construct a constitutive standard model Lie group in the Minkowski Clifford algebra which has two-valued spinors, but no rotation group to cover. Then time, volume and director turn into equivalent thermodynamic magnitudes which are connected by the strong force Pauli principle. Time no longer is bound to some definite scale, but suffers topological defects just like the 3-volume in a wake. The future symmetries mathematicians shall engage with will connect geometry with topology and where physics is concerned: in fundamental observation of dynamic systems, we shall more often dispense with a group in favor of some groupoid which allows for greater freedom of action. The paper begins with a theorem coined by the philosopher Gerhard Frey with whom I shared the conviction that it is difficult to reckon up the big bang. Method of the introduced rigor goes back to Cartan and Clifford and is justified in our days by the works of Kiehn, Fauser and Oziewicz.
Type of Paper: Article
Title: Eigenmodes in Resonators with Broken Time Reversal Symmetry
Author: Victor Dmitriev
Affiliation: Department of Electrical Engineering, Federal University of Para, PO Box 8619, Agencia UFPA, CEP 66075-900, Belem, Para, Brazil; E-mail: victor@ufpa.br
Abstract: In [1], a classification of eigenmodes in radiofrequency cavities for particle accelerators is presented. The classification is based on group theory. However, this work does not take into account the presence of the particle beam and the magnetic field produced by this beam. We show in our paper that the charged particle beam changes the symmetry of the empty cavity. Using the theory of magnetic groups and group-theoretical perturbation method, we discuss some of the consequences of reduction of the resonator symmetry, among them the absence of the Time reversal operator in its “pure” form in the corresponding magnetic groups, changing the resonance frequencies of eigenmodes and lifting of their degeneracy.
References: [1] S. Sakanaka, “Classification of eigenmodes in rf cavities using the group theory”, Physical Review Special Topics: Accelerators and Beams, Vol. 8, 072002, 2005.
Title: Role of Symmetry in Proton Phototransfer Reactions Undergone Between Nitrogenous Base-Pairs Linked by Means of Multiple Intermolecular Hydrogen Bonds
Author: J. Catalán; E-mail: javier.catalan@uam.es
Abstract: Using the 7-azaindole dimer as a functional model of the DNA base pairs it will be demonstrated that if this dimer possesses C2h symmetry, on photoexcitation it undergoes a double proton-transfer which is concerted. If the dimer does not possess centrosymmetry, on photoexcitation it undergoes a single proton-transfer reaction. This evidence mentioned above together with that the base pairs which controlled the genetic code in DNA do not possess centrosymmetry lead to draw the conclusion of that the DNA base pairs are on electronic excitation might only undergo a single proton-transfer process. In conclusion, the mutational mechanisms induced by photo-absorption on multiple intermolecular hydrogen bonded systems must be revisited.
Type of Paper: Review
Author: Peter Leach; E-mail: leachp@ukzn.ac.za
Title: The Essence of Symmetry Analysis of Differential Equations Now
Abstract: We review the development of the concept of the symmetry analysis over the past 140 years and make a new proposal which unifies the concept in the light of present knowledge and one hopes give guidance to future developments of this field.
Title: Fluctuating Asymmetry: Theory, Methods, and Applications
Authors: John H. Graham1, Shmuel Raz2, Hagit Hel-Or3, and Eviatar Nevo2
Affiliations:1Department of Biology, Berry College, Mount Berry, Georgia, 30149 USA
2Institute of Evolution, University of Haifa, Haifa 31905 ISRAEL; E-mail: nevo@research.haifa.ac.il
3Department of Computer Science, University of Haifa, Haifa 31905 ISRAEL
Abstract: Symmetry is ubiquitous in the living world. Even sponges, which are widely regarding as lacking symmetry, have fractal symmetry (i.e., symmetry of scale). These symmetries, however, are approximate and only large-sample averages approach perfect symmetry. The extent to which the average individual departs from perfect symmetry is called fluctuating asymmetry, which has numerous applications in evolutionary biology, quantitative genetics, environmental biology, conservation biology, anthropology, and medicine. Fluctuating asymmetry is a measure of developmental noise, and may reflect a population’s state of adaptation and genomic coadaptation. As such, it indicates when stress is severe enough to disturb development. Here, we review the origins of fluctuating asymmetry, as it is presently understood, as well as methods of measuring it. We also present examples of fluctuating bilateral, radial, rotational, translatory, and fractal asymmetries from the literature, and from our own research.
Title: Replication and Abstraction: On Symmetry in Automated Formal Verification
Author: Thomas Wahl and Alastair Donaldson
Affiliation: Wolfson Building, Parks Road, Oxford OX1 3QD; Email: wahl@comlab.ox.ac.uk
Abstract: The term "Automated formal verification" refers to a collection of mathematically rigorous methods for algorithmically finding errors in, or establish the correctness of, programs or hardware systems. By far the most successful of these methods is model checking, where systems are modeled using finite-state transition graphs. The ability to produce a counterexample witnessing a design flaw has made this technique especially valuable for concurrent system analysis. Concurrent systems, on the other hand, suffer tremendously from the state space explosion problem: the number of distinct configurations that have to be searched for errors is exponential in the number of concurrent components. In practice, concurrency is frequently due to replication: the existence of many parallel components with essentially the same functionality. Examples include replicated worker threads in a client-server software architecture, and hardware designs with replicated physical components. Fortunately, replication tends to engender systems of regular structure: systems exhibiting symmetry. In this paper, we tell the story of symmetry reduction in model checking. We define what symmetry means in model checking, and describe symmetry reduction as an abstraction technique. We highlight the most successful approaches to verify symmetry abstractions of system models, rather than the models themselves. We also discuss tool implementations of such approaches, and assess the success these tools have had in making model checking of large systems more efficient. We conclude with an outlook on the prospects of symmetry reduction research for the formal analysis of computing systems of today and tomorrow.
Title: To be added soon
Author: Franco Buccella; Email: buccella@na.infn.it
Abstract: The Lie algebras are described as a generalization of the angular momentum algebra and their irreducible representations are classified. We concentrate on the applications to elementary particles, starting from isospin, the eightfold way and the flavour spin SU(6) symmetry. Then the standard model with his gauge group SU(3) x SU(2) x U(1) is described with his extensions SU(5) and SO(10), the latter supported by his ability to embed in a natural way the see-saw model advocated to account for the order of magitude of neutrino masses. General methods to construct the symmetry breaking patterns suggested by experiment will be discussed. Finally the mathematical relationship of the exceptional algebras with optonions (and of the symplectic ones with quaternions) will be shown.
Type of Paper: Article
Title: Orientational Sampling Schemes Based on
Four-Dimensional Regular Polytopes
Author: Malcolm Levitt; Email: malcolm.levitt@soton.ac.uk
Abstract: Many problems in the physical sciences require uniform sampling of three-dimensional orientational space. We show that uniformly distributed points in three-dimensional orientational space may be generated from the vertices of four-dimensional uniform polytopes (polychora). We review the group theory of four-dimensional regular polytopes, and determine the conditions under which Wigner rotation matrices vanish when summed over the sets of rotations corresponding to the polytope vertices. We provide tables of Euler angles derived from the vertices of the uniform polychora, which may be used directly for the numerical calculations of orientational averages, and in the spectroscopy of anisotropic systems, such as solid-state nuclear magnetic resonance.
Title: Symmetry and ionization spectra of small alkanes and fluorinated benzenes
Authors: Zejin Yang1,2, Lalitha Selvam1, Xiangdon Yang2 and Feng Wang1*
Affiliations: 1Centre for Molecular Simulation, Swinburne University of Technology, P. O. Box 218, Hawthorn, Melbourne, Victoria, Australia
2Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, The P. R. China
*Author to whom correspondence should be addressed; E-Mail: fwang@swin.edu.au
Abstract: Ionization spectra in both valence and core spaces of small alkanes (n<=6) and fluorinated benzenes are simulated using density functional theory (DFT) models. The ionization potentials (IP) are compared with other theoretical models such as outer valence Green function (OVGF), as well as available experiment. Inner shell ionization spectra of the species exhibit a clear point group symmetry dependent trend, when the alkane chain grows longer or branches to produce isomers, or the hydrogen atoms of benzene are replaced by fluorine atoms. In the valence shell, an orbital based analysis are given using dual space analysis (DSA) [1] using information from both coordinate space and momentum space. Based on the orbital momentum distributions (MD) of the species, total molecular momentum distributions (MMD), which are closely related to Compton profiles, are calculated and reported in Figure 1 and Figure 2. The total MMD indicate certain symmetry related characteristics revealing the carbon chain growth of the alkanes and fluorine substitutions of benzene from momentum space. In order to assist the illustration of the structures and orbitals in three-dimensional (3D) space, the present study will employ the most recently developed interactive 3D-PDf technique [2].
References: [1] Wang, F. Assessment of Quantum Mechanical Models Based on Resolved Orbital Momentum Distributions of n-Butane in the Outer Valence Shell. J. Phys. Chem. A, 2003, 107, pp 10199–10207.
[2] Selvam, L.; Vasilyev, V.; Wang, F. J. Phys. Chem.B 2009 (in press, ASAP: http://pubs.acs.org/doi/abs/10.1021/jp901678g)
Type of Paper: Article
Title: Application of symmetry methods to low-dimensional Heisenberg magnets
Authors: I.G. Bostrem, A.S. Ovchinnikov, V.E. Sinitsyn; E-mail: alexander.ovchinnikov@usu.ru
Affiliation: Ural State University, Ekaterinburg, Russia
Abstract: An account of symmetry is very fruitful in studies of quantum spin systems. In the present paper we demonstrate how to use the spin SU(2) and the point symmetries in optimization of the theoretical condensed matter tools: the exact diagonalization, the renormalization group approach, the cluster perturbation theory. We apply the methods for study of Bose-Einstein condensation in dimerized antiferromagnets, for investigations of magnetization processes and magnetocaloric effect in low-dimensional spin systems.
Title: Symmetry: Mathematical Structures and Art
Author: Michele Emmer; E-mail: emmer@mat.uniroma1.it
Abstract: to be added soon
Title: Symmetry breaking with Higgs singlets and doublets
Authors: Nuno Barros e Sá and Rui Santos; E-mail: rsantos@cii.fc.ul.pt
Affiliation: Universidade dos Açores, Portugal and University of Southampton, UK
Abstract: We discuss spontaneous symmetry breaking in quantum field theory with an arbitrary number of singlets and doublets. The potential responsible for generating all known particle masses is build with just one scalar doublet in the so-called Standard Model of Electroweak Interactions (SM). However there is no evidence or hint on how this potential should look like. We discuss several possibilities of symmetry breaking in potentials other then the SM one.
Type of paper: Article
Title: On the two symmetries of solids
Author: Dr. Ulrich Köbler; E-mail: u.koebler@fz-juelich.de
Affiliation: Forschungszentrum Jülich, Institut IFF
Abstract: to be added soon
Type of Paper: Review
Title: Symmetric and Asymmetric Somatic Hybridization in Citrus spp.
Authors: Claudine M. de Bona1, Dayse C. de Carvalho2, Eliezer S. Louzada3, J. Creighton Miller Jr.4 and David Stelly5
Affiliations: 1 IAPAR, Agronomic Institute of Parana. Rod. do Cafe, km 496, Av. Presidente Kennedy, PR, Brazil; E-mail: debona@iapar.br
2 UFPR, Federal University of Parana, Curitiba, PR, Brazil; E-mail: daysecristy@yahoo.com.br
3 TAMUK, Texas A&M University - Kingsville. Citrus Center, Weslaco, TX, USA; E-mail: e-louzada@tamu.edu
4 TAMU, Texas A&M University. Department of Horticultural Sciences, College Station, TX, USA; E-mail: jcmillerjr@tamu.edu
5 TAMU, Texas A&M University. Department of Soil and Crop Sciences, New Beasley Lab, Texas A&M University, College Station, Texas, USA; E-mail: stelly@tamu.edu
Abstract: Hybridization by means of somatic nuclear or cytoplasmic fusions lead to three distinct possible outcomes -- [1] “symmetric” hybrid: fusion of whole nuclei, [2] “asymmetric” hybrid: fusion of parental nuclei, one or both deficient for one or more chromosome(s), and [3] “cybrid”: fusion without a nuclear contribution by one parent. The introduction of desirable agronomic characteristics into improved plant materials is a major application of the somatic hybridization by protoplast fusion. In this review, advantages of symmetric and asymmetric somatic hybridization and cybridization as tools for genetic improvement of Citrus spp. will be further discussed.
Keywords: symmetry; asymmetry; protoplast fusion; hybrids; cybrids; genetic improvement; citrus breeding; scion; rootstock; germplasm
Title: The Symmetry of Reactions — Atomic and Molecular Reaction Statics
Author: Zhenghe Zhu; E-mail: zhuxm@scu.edu.cn
Affiliation: Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China
Abstract: It is well known that the symmetry for the static states of atoms or molecules,and the symmetry for the transition of atoms or molecules, etc., However, it is really needed the symmetry for the atomic and molecular reaction. For example, the ground state for BaO is X1Σ+ ,from the reaction of Ba + O → BaO (X1Σ+),what are the possible states for both atoms Ba and O by symmetry.It is impossible if both Ba and O are in their ground state,however, one of them must be the excited state ,otherwise , both the multiplicity and“+,-”symmetry are forbidden.
This work presents a new science called atomic and molecular reaction statics (AMRS),which is related with the symmetry for atomic and molecular reactions.There are four parts for AMRS, i.e. group theoretical derivation of molecular electronic states, the principle of microscopic reversibility, the principle of microscopic transitivity and the optimum energy process rule. There are some of applications examples.AMRS has been developed for about twenty years.
Atomic and molecular reaction statics (AMRS) is necessary for the completeness of science. The chemical kinetics without chemical thermodynamics is unthinkable,and the molecular reaction dynamics without atomic and molecular reaction statics is also unthinkable,
Keywords: atomic and molecular reaction statics; group theoretical derivation; the principle of microscopic reversibility; the principle of microscopic transitivity
Title: Unconventional Introduction to the Internal Symmetries of Modern Field Theories: From Doppler Effect to Gauge Invariance.
Authors: Giuseppe Buccheri and Fabio Siringo
Affiliation: Dipartimento di Fisica e Astronomia, Universitµa di Catania, INFN Sezione di Catania and CNISM Sezione di Catania, Via S.Sofia 64, I-95123 Catania, Italy; E-mail: fabio.siringo@ct.infn.it
Abstract: In original introduction to gauge invariance is provided by the use of simple pedagogical arguments. A basic problem on Doppler effect is shown to be related to deep insights on the nature of the field theory which describes the photon. A non-trivial symmetry emerges that is necessary for the Lorentz invariance of local field theories, and the general properties of photons are recovered without any explicit use of Maxwell equations. Phenomenological aspects of gauge invariance are then discussed, and some processes are reviewed where the "internal" gauge symmetry gives rise to relevant macroscopic observable effects, like superconductivity and the quantum Hall effect.
Type of Paper: Review
Title: Comments on Symmetry and Asymmetry in the Physical and Biological World
Author: David B. Cline; E-mail: dcline@physics.ucla.edu
Affiliation: Physics & Astronomy Department, College of Letters & Sciences, UCLA, Los Angeles, CA, USA
Abstract: We barely define the concept of symmetry in the Physical World and recount the Key developments such as the Conservation of Energy that arise from symmetry principles. We than briefly discuss the role of symmetry breaking such as in the broken SU (2) X U (1) symmetry of the standard model of elementary particles. In the biological world one key to life seems to be chiral symmetry breaking –such as the fact that 19 out of 20 Amino Acids in life are left bonded. The key question is whether the asymmetry in the Physical World has some how caused the chiral symmetry breaking in life processes. We cite some examples of this possibility.
Type of Paper: Article
Title: Symmetry of knots reflected in Jones type invariants
Author: Jozef Przytycki; E-Mail: przytyck@gmail.com
Abstract: Symmetry of geometrical figures is reflected in regularities of their algebraic invariants. Algebraic regularities are often preserved when the geometrical figure is topologically deformed.
Title: Symmetry and Asymmetry Level Measures
Author: Angel Garrido
Affiliation: Departamentos de Matematicas Fundamentales e Inteligencia Artificial, Facultad de Ciencias/Escuela Tecnica Superior de Ingenieria Informatica de la UNED, Spain; E-Mail: agarrido@mat.uned.es
Abstract: Usually, the Symmetry, and dually the Asymmetry, can be considered as the two sides of the same coin: an object will be totally symmetric, or totally asymmetric, relative to a pattern object, without ntermediate situations, of partial symmetry or partial asymmetry. But this dichotomical classification, because their simplicity, suffer a lack of necessary and realistic grades. For this reason, it is convenient the introduction of shade regions", modulating the degrees (a fuzzy concept). So, we will analyze here the Asymmetry problem, with its previous distinct attempts of description, introducing the new concept of Symmetry/Asymmetry Level Function, as a Normal Fuzzy Measure".
Type of Paper: Review
Title: Symmetries of the Central Vestibular System: Forming Movements for Gravity and a Three-Dimensional World
Authors: Gin McCollum and Douglas A. Hanes; E-Mail: mccollum@ohsu.edu
Abstract: Intrinsic dynamics of the central vestibular system appear to be at least partly determined by the symmetries of its connections. The central vestibular system contributes to whole-body functions such as upright balance and maintenance of gaze direction. These functions coordinate disparate senses (visual, inertial, somatosensory, auditory) and body movements (leg, trunk, head/neck, eye). They are also unified by geometric conditions. Symmetry groups have been found to structure experimentally-recorded pathways of the central vestibular system. When related to geometric conditions in three-dimensional physical space, these symmetry groups make sense as a logical foundation for sensorimotor coordination.
Type of Paper: Review
Title: Fluctuating Asymmetry in Flies; What Does it Mean?
Author: Athol J. McLachlan
Affiliation: Newcastle University, UK; E-mail: a.j.mclachlan@virgin.net
Abstract: The degree of left/right symmetry in organisms, fluctuating asymmetry (FA) within a population, is seen in both humans and flies, among many others. FA is currently subject to intense interest and research. It has particular impact on choice of mate which lies within Charles Darwin’s sexual selection universe where success at mating is the ultimate measure of Darwinian fitness. Exaggerated sexual display ornaments have typically evolved under this kind of selection and include the peacock’s tail and the weapons as sexual display ornaments seen, for example, in the antlers of both stags and stag beetles. The degree of symmetry in these devices has provided the focus of much of the interest. Here I consider a less well studied aspect of symmetry, i.e. contests between males for mates based, not on display but instead on agility such as that seen in insects and fish that mate in a three dimensional arena; air and water respectively. The model organism considered in this review is the ubiquitous chironomid midge. In these flies, mating takes place in the air so symmetry in the length of wings bares directly on a males aerobatic ability on which successful mating depends. Within this framework I give special attention to the selective pressures imposed by parasites and predators. Finally, note of caution is sounded in over enthusiastic acceptance of the role of FA in sexual selection.
Type of Paper: Article
Title: Symmetric matrix fields in the finite element method
Author: Gerard Awanou; E-Mail: awanou@math.niu.edu
Abstract: to be added
Type of Paper: Review
Title: Bilateral Symmetry Detection using Computer Vision
Author: Wai Ho Li; E-Mail: Wai.Ho.Li@eng.monash.edu.au
Abstract: Bilateral Symmetry is an inherently interesting visual feature. From architecture to furniture, art to mathematics, humans strive for perfect symmetry. Random configurations of objects are rarely symmetric, making symmetry a salient feature for visual attention. Due to its role in human visual perception, the automatic detection of bilateral symmetry has been an active research area in Computer Vision since the 1960’s. Research in symmetry detection using computer vision is reviewed, spanning over four decades. Applications of symmetry detection with example results are provided at the end of the paper.
Last update: 19 March 2010