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Note: This page contains sample records for the topic "discrete space-time symmetries" from the National Library of EnergyBeta (NLEBeta).
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We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

Optical Activities as Computing Resources for Space-time Symmetries  

E-Print Network [OSTI]

It is known that optical activities can perform rotations. It is shown that the rotation, if modulated by attenuations, can perform symmetry operations of Wigner's little group which dictates the internal space-time symmetries of elementary particles.

Y. S. Kim

2009-02-23T23:59:59.000Z

2

From Discrete Space-Time to Minkowski Space: Basic Mechanisms, Methods and Perspectives  

E-Print Network [OSTI]

This survey article reviews recent results on fermion system in discrete space-time and corresponding systems in Minkowski space. After a basic introduction to the discrete setting, we explain a mechanism of spontaneous symmetry breaking which leads to the emergence of a discrete causal structure. As methods to study the transition between discrete space-time and Minkowski space, we describe a lattice model for a static and isotropic space-time, outline the analysis of regularization tails of vacuum Dirac sea configurations, and introduce a Lorentz invariant action for the masses of the Dirac seas. We mention the method of the continuum limit, which allows to analyze interacting systems. Open problems are discussed.

Felix Finster

2008-02-22T23:59:59.000Z

3

Physics in discrete spaces (A): Space-Time organization  

E-Print Network [OSTI]

We put forward a model of discrete physical space that can account for the structure of space- time, give an interpretation to the postulates of quantum mechanics and provide a possible explanation to the organization of the standard model of particles.

P. Peretto

2010-12-29T23:59:59.000Z

4

The Modification of the Oppenheimer and Snyder Collapsing Dust Ball to a Static Ball in Discrete Space-time  

E-Print Network [OSTI]

Besides the singularity problem, the famous Oppenheimer and Snyder solution is discovered to be of deficiency in two aspects: the internal Friedmann space-time does not have the inherent symmetry and cannot connect to the external Schwarzschild space-time. So the process of gravitational collapse described by this solution is doubtful. The deficiency, together with the singularity problem, result from the imperfection of the field theory in continuous space-time, which is expressed by the infinite precision function theory. The space-time structure of the Oppenheimer and Snyder dust ball is founded to be discrete rather than continuous, and to describe the field theory in discrete space-time it requires a function theory with finite precision. Based on the i order real number and its equivalence class, which is defined in the real number field, the infinite precision function theory is extended to the finite precision function theory. The Einstein field equations are expressed in the form of finite precision, and then the collapsing dust ball solution in continuous space-time is modified to a static ball solution in discrete space-time. It solves all the problems of Oppenheimer and Snyder solution and shows that, with Planck length and Planck time as space-time quantum, a mechanism to resist the gravitational collapse could be obtained by the discretization of space-time.

G. Chen

2008-08-27T23:59:59.000Z

5

Discrete R Symmetries and Low Energy Supersymmetry  

E-Print Network [OSTI]

MN-2 )1/N+1 . (8) But the minimum near the origin persists, with positive energy ( f2), so the susyDiscrete R Symmetries and Low Energy Supersymmetry UC Davis, 2011 Michael Dine Department R Symmetries and Low Energy Supersymmetry #12;Plan for Today: "New, Improved" Models of Dynamical

California at Santa Cruz, University of

6

Internal Space-time Symmetries of Particles derivable from Periodic Systems in Optics  

E-Print Network [OSTI]

While modern optics is largely a physics of harmonic oscillators and two-by-two matrices, it is possible to learn about some hidden properties of the two-by-two matrix from optical systems. Since two-by-two matrices can be divided into three conjugate classes depending on their traces, optical systems force us to establish continuity from one class to another. It is noted that those three classes are equivalent to three different branches of Wigner's little groups dictating the internal space-time symmetries massive, massless, and imaginary-mass particles. It is shown that the periodic systems in optics can also be described by have the same class-based matrix algebra. The optical system allow us to make continuous, but not analytic, transitions from massiv to massless, and massless to imaginary-mass cases.

Y. S. Kim

2010-09-26T23:59:59.000Z

7

Discrete Abelian gauge symmetries and axions  

E-Print Network [OSTI]

We combine two popular extensions of beyond the Standard Model physics within the framework of intersecting D6-brane models: discrete Zn symmetries and Peccei-Quinn axions. The underlying natural connection between both extensions is formed by the presence of massive U(1) gauge symmetries in D-brane model building. Global intersecting D6-brane models on toroidal orbifolds of the type T6/Z2N and T6/Z2xZ2M with discrete torsion offer excellent playgrounds for realizing these extensions. A generation-dependent Z2 symmetry is identified in a global Pati-Salam model, while global left-right symmetric models give rise to supersymmetric realizations of the DFSZ axion model. In one class of the latter models, the axion as well as Standard Model particles carry a non-trivial Z3 charge.

Honecker, Gabriele

2015-01-01T23:59:59.000Z

8

Discrete Abelian gauge symmetries and axions  

E-Print Network [OSTI]

We combine two popular extensions of beyond the Standard Model physics within the framework of intersecting D6-brane models: discrete Zn symmetries and Peccei-Quinn axions. The underlying natural connection between both extensions is formed by the presence of massive U(1) gauge symmetries in D-brane model building. Global intersecting D6-brane models on toroidal orbifolds of the type T6/Z2N and T6/Z2xZ2M with discrete torsion offer excellent playgrounds for realizing these extensions. A generation-dependent Z2 symmetry is identified in a global Pati-Salam model, while global left-right symmetric models give rise to supersymmetric realizations of the DFSZ axion model. In one class of the latter models, the axion as well as Standard Model particles carry a non-trivial Z3 charge.

Gabriele Honecker; Wieland Staessens

2015-02-03T23:59:59.000Z

9

Quantization of Point Particles in 2+1 Dimensional Gravity and Space-Time Discreteness  

E-Print Network [OSTI]

By investigating the canonical commutation rules for gravitating quantized particles in a 2+1 dimensional world it is found that these particles live on a space-time lattice. The space-time lattice points can be characterized by three integers. Various representations are possible, the details depending on the topology chosen for energy-momentum space. We find that an $S_2\\times S_1$ topology yields a physically most interesting lattice within which first quantization of Dirac particles is possible. An $S_3$ topology also gives a lattice, but does not allow first quantized particles.

G. 't Hooft

1996-01-10T23:59:59.000Z

10

Hamilton Operators, Discrete Symmetries, Brute Force and SymbolicC++  

E-Print Network [OSTI]

To find the discrete symmetries of a Hamilton operator $\\hat H$ is of central importance in quantum theory. Here we describe and implement a brute force method to determine the discrete symmetries given by permutation matrices for Hamilton operators acting in a finite-dimensional Hilbert space. Spin and Fermi systems are considered as examples. A computer algebra implementation in SymbolicC++ is provided.

Willi-Hans Steeb; Yorick Hardy

2012-08-23T23:59:59.000Z

11

Discrete symmetry in graphene: the Dirac equation and beyond  

E-Print Network [OSTI]

In this pedagogical paper we review the discrete symmetries of the Dirac equation using elementary tools, but in a comparative order: the usual 3 + 1 dimensional case and the 2 + 1 dimensional case. Motivated by new applications of the 2d Dirac equation in condensed matter, we further analyze the discrete symmetries of a full tight-binding model in hexagonal lattices without conical approximations. We touch upon an effective CPT symmetry breaking that occurs when deformations and second-neighbor corrections are considered.

Sadurní, Emerson; Rosado, Alfonso

2014-01-01T23:59:59.000Z

12

Anomalies of discrete symmetries in various dimensions and group cohomology  

E-Print Network [OSTI]

We study 't Hooft anomalies for discrete global symmetries in bosonic theories in 2, 3 and 4 dimensions. We show that such anomalies may arise in gauge theories with topological terms in the action, if the total symmetry group is a nontrivial extension of the global symmetry by the gauge symmetry. Sometimes the 't Hooft anomaly for a d-dimensional theory with a global symmetry G can be canceled by anomaly inflow from a (d+1)-dimensional topological gauge theory with gauge group G. Such d-dimensional theories can live on the surfaces of Symmetry Protected Topological Phases. We also give examples of theories with more severe 't Hooft anomalies which cannot be canceled in this way.

Anton Kapustin; Ryan Thorngren

2014-04-16T23:59:59.000Z

13

Weakly bound molecules trapped with discrete scaling symmetries  

E-Print Network [OSTI]

When the scattering length is proportional to the distance from the center of the system, two particles are shown to be trapped about the center. Furthermore, their spectrum exhibits discrete scale invariance, whose scale factor is controlled by the slope of the scattering length. While this resembles the Efimov effect, our system has a number of advantages when realized with ultracold atoms. We also elucidate how the emergent discrete scaling symmetry is violated for more than two bosons, which may shed new light on Efimov physics. Our system thus serves as a tunable model system to investigate universal physics involving scale invariance, quantum anomaly, and renormalization group limit cycle, which are important in a broad range of quantum physics.

Yusuke Nishida; Dean Lee

2012-09-12T23:59:59.000Z

14

Contacts of space--times  

SciTech Connect (OSTI)

The concept of contact between manifolds is applied to space--times of general relativity. For a given background space--time a contact approximation of second order is defined and interpreted both from the point of view of a metric pertubation and of a higher order tangent manifold. In the first case, an application to the high frequency gravitational wave hypothesis is suggested. In the second case, a constant curvature tangent bundle is constructed and suggested as a means to define a ten parameter local space--time symmetry.

Maia, M.D.

1981-03-01T23:59:59.000Z

15

Discrete and continuous symmetries in multi-Higgs-doublet models  

SciTech Connect (OSTI)

We consider the Higgs sector of multi-Higgs-doublet models in the presence of simple symmetries relating the various fields. We construct basis-invariant observables which may in principle be used to detect these symmetries for any number of doublets. A categorization of the symmetries into classes is required, which we perform in detail for the case of two and three Higgs doublets.

Ferreira, P. M. [Instituto Superior de Engenharia de Lisboa, Rua Conselheiro Emidio Navarro, 1900 Lisboa (Portugal); Centro de Fisica Teorica e Computacional, Faculdade de Ciencias, Universidade de Lisboa, Avenida Professor Gama Pinto 2, 1649-003 Lisboa (Portugal); Silva, Joao P. [Instituto Superior de Engenharia de Lisboa, Rua Conselheiro Emidio Navarro, 1900 Lisboa (Portugal); Centro de Fisica Teorica de Particulas, Instituto Superior Tecnico, P-1049-001 Lisboa (Portugal)

2008-12-01T23:59:59.000Z

16

Fuzzy Space-Time  

E-Print Network [OSTI]

A review is made of recent efforts to define linear connections and their corresponding curvature within the context of noncommutative geometry. As an application it is suggested that it is possible to identify the gravitational field as a phenomenological manifestation of space-time commutation relations and to thereby clarify its role as an ultraviolet regularizer.

J. Madore

1996-07-26T23:59:59.000Z

17

A Vector-Like Fourth Generation with A Discrete Symmetry From Split-UED  

SciTech Connect (OSTI)

Split-UED allows for the possibility that the lowest lying KK excitations of the Standard Model fermions can be much lighter than the corresponding gauge or Higgs KK states. This can happen provided the fermion bulk masses are chosen to be large, in units of the inverse compactification radius, 1/R, and negative. In this setup, all of the other KK states would be effectively decoupled from low energy physics. Such a scenario would then lead to an apparent vector-like fourth generation with an associated discrete symmetry that allows us to accommodate a dark matter candidate. In this paper the rather unique phenomenology presented by this picture will be examined.

Kong, Kyoungchul; /SLAC; Park, Seong Chan; /Tokyo U., IPMU; Rizzo, Thomas G.; /SLAC

2011-08-19T23:59:59.000Z

18

Space time and rotations  

E-Print Network [OSTI]

The paper considers the problem of finding the metric of space time around a rotating, weakly gravitating body. Both external and internal metric tensors are consistently found, together with an appropriate source tensor. All tensors are calculated at the lowest meaningful approximation in a power series. The two physical parameters entering the equations (the mass and the angular momentum per unit mass) are assumed to be such that the mass effects are negligible with respect to the rotation effects. A non zero Riemann tensor is obtained. The order of magnitude of the effects at the laboratory scale is such as to allow for experimental verification of the theory.

A. Tartaglia

2002-01-04T23:59:59.000Z

19

Metastring Theory and Modular Space-time  

E-Print Network [OSTI]

String theory is canonically accompanied with a space-time interpretation which determines S-matrix-like observables, and connects to the standard physics at low energies in the guise of local effective field theory. Recently, we have introduced a reformulation of string theory which does not rely on an {\\it a priori} space-time interpretation or a pre-assumption of locality. This \\hlt{metastring theory} is formulated in such a way that stringy symmetries (such as T-duality) are realized linearly. In this paper, we study metastring theory on a flat background and develop a variety of technical and interpretational ideas. These include a formulation of the moduli space of Lorentzian worldsheets, a careful study of the symplectic structure and consequently consistent closed and open boundary conditions, and the string spectrum and operator algebra. What emerges from these studies is a new quantum notion of space-time that we refer to as a quantum Lagrangian or equivalently a \\hlt{modular space-time}. This concept embodies the standard tenets of quantum theory and implements in a precise way a notion of {relative locality}. The usual string backgrounds (non-compact space-time along with some toroidally compactified spatial directions) are obtained from modular space-time by a limiting procedure that can be thought of as a correspondence limit.

Laurent Freidel; Robert G. Leigh; Djordje Minic

2015-02-27T23:59:59.000Z

20

Space-time attributes of physical objects and the laws of space-time physics  

E-Print Network [OSTI]

Physical time intervals are attributes of single physical object whereas physical space intervals are a relational attribute of two physical objects. Some consequences of the breaking of the space-time exchange symmetry inherent in the Lorentz transformation following from the above distinction are investigated. In particular, it is shown that the relativity of simultaneity and length contraction effects which naively follow from space-time symmetry of the Lorentz transformation do not occur. Seven laws describing the relation between observations of space intervals, time intervals and velocities in different reference frames are given. Only two of these laws are respected by conventional special relativity theory.

J. H. Field

2008-09-24T23:59:59.000Z

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


21

High Harmonic Generation and Polarization: Angular Momentum Conservation vs Discrete Time-Dependent Symmetries  

E-Print Network [OSTI]

We discuss the place of angular momentum conservation in theoretical and numerical models for high harmonic generation (HHG). Recent experimental work [A. Fleischer et al., Nature Photonics 8, 543 (2014)] has shown conflicting results regarding the conservation of the (photon) angular momentum in HHG. Here we show that simulations using classical (laser and HHG) fields do not conserve angular momentum and that the properties of HHG spectra are actually due to more general discrete time-dependent symmetries that apply equally well for atoms and molecules (here illustrated with He, H3+, Ne+ and H2 models). To conclude, we propose a configuration to test for the accuracy of these simulations compared to selection rule predictions.

Mauger, F; Uzer, T

2015-01-01T23:59:59.000Z

22

Space, time and machines  

E-Print Network [OSTI]

The 2nd law of thermodynamics is used to shed light on present-day puzzles in cosmology. The universal law, given as an equation of motion, describes diverse systems when consuming free energy via various mechanisms to attain stationary states in their respective surroundings. Expansion of the Universe, galactic rotation and lensing as well as clustering of red-shifted spectral lines are found as natural consequences of the maximal energy dispersal that satisfies the conservation of energy, in the forms of kinetic, potential and dissipation. The Universe in its entirety is pictured as a giant Riemann resonator in evolution via step-by-step spontaneous breaking of one stationary-state symmetry to another to diminish energy density differences relative to its zero-density "surroundings". The continuum equation of evolution is proven equivalent to the Navier-Stokes equation. The ubiquitous flow equation has no solution because the forces and flows are inseparable when the dissipative process has three or more degrees of freedom. Since an evolving system is without a norm, there is no unitary transformation to solve the characteristic equation, but detailed trajectories remain inherently intractable. Conversely, stationary-state trajectories can be solved.

Arto Annila

2012-06-19T23:59:59.000Z

23

Metastring Theory and Modular Space-time  

E-Print Network [OSTI]

String theory is canonically accompanied with a space-time interpretation which determines S-matrix-like observables, and connects to the standard physics at low energies in the guise of local effective field theory. Recently, we have introduced a reformulation of string theory which does not rely on an {\\it a priori} space-time interpretation or a pre-assumption of locality. This \\hlt{metastring theory} is formulated in such a way that stringy symmetries (such as T-duality) are realized linearly. In this paper, we study metastring theory on a flat background and develop a variety of technical and interpretational ideas. These include a formulation of the moduli space of Lorentzian worldsheets, a careful study of the symplectic structure and consequently consistent closed and open boundary conditions, and the string spectrum and operator algebra. What emerges from these studies is a new quantum notion of space-time that we refer to as a quantum Lagrangian or equivalently a \\hlt{modular space-time}. This conce...

Freidel, Laurent; Minic, Djordje

2015-01-01T23:59:59.000Z

24

Introduction Space Time Codes Space Time Coding with Feedback New Thoughts Summary Space-Time Coding for Multi-Antenna  

E-Print Network [OSTI]

Introduction Space Time Codes Space Time Coding with Feedback New Thoughts Summary Space 2007 #12;Introduction Space Time Codes Space Time Coding with Feedback New Thoughts Summary MIMO: Diversity vs Multiplexing Multiplexing Diversity Pictures taken from lectures notes on Space Time Coding

Veeravalli, Venugopal

25

Some symmetries in nuclei  

SciTech Connect (OSTI)

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)

Henley, E.M.

1981-09-01T23:59:59.000Z

26

Discrete canonical analysis of three dimensional gravity with cosmological constant  

E-Print Network [OSTI]

We discuss the interplay between standard canonical analysis and canonical discretization in three-dimensional gravity with cosmological constant. By using the Hamiltonian analysis, we find that the continuum local symmetries of the theory are given by the on-shell space-time diffeomorphisms, which at the action level, corresponds to the Kalb-Ramond transformations. At the time of discretization, although this symmetry is explicitly broken, we prove that the theory still preserves certain gauge freedom generated by a constant curvature relation in terms of holonomies and the Gauss's law in the lattice approach.

J. Berra-Montiel; J. E. Rosales-Quintero

2014-06-03T23:59:59.000Z

27

Noncommutative space-time models  

E-Print Network [OSTI]

The FRT quantum Euclidean spaces $O_q^N$ are formulated in terms of Cartesian generators. The quantum analogs of N-dimensional Cayley-Klein spaces are obtained by contractions and analytical continuations. Noncommutative constant curvature spaces are introduced as a spheres in the quantum Cayley-Klein spaces. For N=5 part of them are interpreted as the noncommutative analogs of (1+3) space-time models. As a result the quantum (anti) de Sitter, Newton, Galilei kinematics with the fundamental length and the fundamental time are suggested.

N. A. Gromov; V. V. Kuratov

2005-07-01T23:59:59.000Z

28

E-Print Network 3.0 - abstract relational space-time Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Summary: Methods in Applied Sciences and Engineering (ECCOMAS 2008) June 30 -July 5, 2008 Venice, Italy SPACE-TIME... may conserve discrete energy. Hence, in the present work, we...

29

A Potential Foundation for Emergent Space-Time  

E-Print Network [OSTI]

We present a novel derivation of both the Minkowski metric and Lorentz transformations from the consistent quantification of a causally ordered set of events with respect to an embedded observer. Unlike past derivations, which have relied on assumptions such as the existence of a 4-dimensional manifold, symmetries of space-time, or the constant speed of light, we demonstrate that these now familiar mathematics can be derived as the unique means to consistently quantify a network of events. This suggests that space-time need not be physical, but instead the mathematics of space and time emerges as the unique way in which an observer can consistently quantify events and their relationships to one another. The result is a potential foundation for emergent space-time.

Kevin H. Knuth; Newshaw Bahreyni

2014-12-19T23:59:59.000Z

30

Anomalous discrete chiral symmetry in the Gross-Neveu model and loop gas simulations  

E-Print Network [OSTI]

We investigate the discrete chiral transformation of a Majorana fermion on a torus. Depending on the boundary conditions the integration measure can change sign. Taking this anomalous behavior into account we define a chiral order parameter as a ratio of partition functions with differing boundary conditions. Then the lattice realization of the Gross-Neveu model with Wilson fermions is simulated using the recent `worm' technique on the loop gas or all-order hopping representation of the fermions. An algorithm is formulated that includes the Gross-Neveu interaction for N fermion species. The critical line m_c(g) is constructed for a range of couplings at N = 6 and for N = 2, the Thirring model, as examples.

Oliver Bär; Willi Rath; Ulli Wolff

2009-05-27T23:59:59.000Z

31

Space-time Curvature of Classical Electromagnetism  

E-Print Network [OSTI]

The space-time curvature carried by electromagnetic fields is discovered and a new unification of geometry and electromagnetism is found. Curvature is invariant under charge reversal symmetry. Electromagnetic field equations are examined with De Rham co homology theory. Radiative electromagnetic fields must be exact and co exact to preclude unobserved massless topological charges. Weyl's conformal tensor, here called ``the gravitational field'', is decomposed into a divergence-free non-local piece with support everywhere and a local piece with the same support as the matter. By tuning a local gravitational field to a Maxwell field the electromagnetic field's local gravitational field is discovered. This gravitational field carries the electromagnetic field's polarization or phase information, unlike Maxwell's stress-energy tensor. The unification assumes Einstein's equations and derives Maxwell's equations from curvature assumptions. Gravity forbids magnetic monopoles! This unification is stronger than the Einstein-Maxwell equations alone, as those equations must produce the electromagnetic field's local gravitational field and not just any conformal tensor. Charged black holes are examples. Curvature of radiative null electromagnetic fields is characterized.

R. W. M. Woodside

2004-10-08T23:59:59.000Z

32

Discrete Symmetries on the Light Front and a General Relation Connecting Nucleon Electric Dipole and Anomalous Magnetic Moments  

E-Print Network [OSTI]

We consider the electric dipole form factor, F_3(q^2), as well as the Dirac and Pauli form factors, F_1(q^2) and F_2(q^2), of the nucleon in the light-front formalism. We derive an exact formula for F_3(q^2) to complement those known for F_1(q^2) and F_2(q^2). We derive the light-front representation of the discrete symmetry transformations and show that time-reversal- and parity-odd effects are captured by phases in the light-front wave functions. We thus determine that the contributions to F_2(q^2) and F_3(q^2), Fock state by Fock state, are related, independent of the fundamental mechanism through which CP violation is generated. Our relation is not specific to the nucleon, but, rather, is true of spin-1/2 systems in general, be they lepton or baryon. The empirical values of the anomalous magnetic moments, in concert with empirical bounds on the associated electric dipole moments, can better constrain theories of CP violation. In particular, we find that the neutron and proton electric dipole moments echo the isospin structure of the anomalous magnetic moments, kappa^n ~ - kappa^p.

S. J. Brodsky; S. Gardner; D. S. Hwang

2006-02-27T23:59:59.000Z

33

Convergence of Space-Time Discrete Dynamics to Anisotropic ...  

E-Print Network [OSTI]

Oct 31, 2014 ... where ? is the unit (outward) normal of ?. (Note that D? is a symmetric matrix.) The .... boundary of the initial set ?0 is represented by a graph. ...... The simulation is performed using Matlab and Fast Fourier Transform. We start ...

2014-10-31T23:59:59.000Z

34

Gauge Gravity and Space-Time  

E-Print Network [OSTI]

When we discuss problems on gravity, we can not avoid some fundamental physical problems, such as space-time, inertia, and inertial reference frame. The goal of this paper is to discuss the logic system of gravity theory and the problems of space-time, inertia, and inertial reference frame. The goal of this paper is to set up the theory on space-time in gauge theory of gravity. Based on this theory, it is possible for human kind to manipulate physical space-time on earth, and produce a machine which can physically prolong human's lifetime.

Ning Wu

2012-07-11T23:59:59.000Z

35

Gravity in Complex Hermitian Space-Time  

E-Print Network [OSTI]

A generalized theory unifying gravity with electromagnetism was proposed by Einstein in 1945. He considered a Hermitian metric on a real space-time. In this work we review Einstein's idea and generalize it further to consider gravity in a complex Hermitian space-time.

Ali H. Chamseddine

2006-10-09T23:59:59.000Z

36

Pseudo-Z symmetric space-times  

SciTech Connect (OSTI)

In this paper, we investigate Pseudo-Z symmetric space-time manifolds. First, we deal with elementary properties showing that the associated form A{sub k} is closed: in the case the Ricci tensor results to be Weyl compatible. This notion was recently introduced by one of the present authors. The consequences of the Weyl compatibility on the magnetic part of the Weyl tensor are pointed out. This determines the Petrov types of such space times. Finally, we investigate some interesting properties of (PZS){sub 4} space-time; in particular, we take into consideration perfect fluid and scalar field space-time, and interesting properties are pointed out, including the Petrov classification. In the case of scalar field space-time, it is shown that the scalar field satisfies a generalized eikonal equation. Further, it is shown that the integral curves of the gradient field are geodesics. A classical method to find a general integral is presented.

Mantica, Carlo Alberto, E-mail: carloalberto.mantica@libero.it [Physics Department, Università degli Studi di Milano, Via Celoria 16, 20133 Milano (Italy); Suh, Young Jin, E-mail: yjsuh@knu.ac.kr [Department of Mathematics, Kyungpook National University, Taegu 702-701 (Korea, Republic of)

2014-04-15T23:59:59.000Z

37

Space-time and G_2  

E-Print Network [OSTI]

A Weyl structure is a bundle over space-time, whose fiber at each space-time point is a space of maximally isotropic complex tangent planes. We develop the theory of Weyl connections for Weyl structures and show that the requirement that the connection be torsion-free fixes the Weyl connection uniquely. Further we show that to each such Weyl connection, there is naturally associated a (2, 3, 5)-Pfaffian system, as first analyzed by Cartan. We determine the associated G_2-conformal structure and calculate it explicitly in the cases of the Kapadia family of space-times and of the Schwarzschild solution

Boris Doubrov; Jonathan Holland; George Sparling

2009-01-05T23:59:59.000Z

38

Exact Philosophy of Space-Time  

E-Print Network [OSTI]

Starting from Bunge's (1977) scientific ontology, we expose a materialistic relational theory of space-time, that carries out the program initiated by Leibniz, and provides a protophysical basis consistent with any rigorous formulation of General Relativity. Space-time is constructed from general concepts which are common to any consistent scientific theory and they are interpreted as emergent properties of the greatest assembly of things, namely, the world.

Héctor Vucetich

2011-09-26T23:59:59.000Z

39

Space-time singularities and the axion in the Poincare coset models ISO(2,1)/H  

E-Print Network [OSTI]

By promoting an invariant subgroup $H$ of $ISO(2,1)$ to a gauge symmetry of a WZWN action, we obtain the description of a bosonic string moving either in a curved 4-dimensional space--time with an axion field and curvature singularities or in 3-dimensional Minkowski space--time.

Roberto Casadio; Benjamin Harms

1996-06-12T23:59:59.000Z

40

The Lorentz Group, Noncommutative Space-Time, and Nonlinear Electrodynamics in Majorana-Oppenheimer Formalism  

E-Print Network [OSTI]

Non-linear electrodynamics arising in the frames of field theories in non-commutative space-time is examined on the base of the Riemann-Silberstein-Majorana-Oppenheimer formalism. The problem of form-invariance of the non-linear constitutive relations governed by six non-commutative parameters \\theta_{kl} \\sim {\\bf K} = {\\bf n} + i {\\bf m} is explored in detail on the base of the complex orthogonal group theory SO(3.C). Two Abelian 2-parametric small groups, isomorphic to each other in abstract sense, and leaving unchangeable the extended constitutive relations at arbitrary six parameters \\theta_{kl} of effective media have been found, their realization depends explicitly on invariant length {\\bf K}^{2}. In the case of non-vanishing length a special reference frame in which the small group has the structure SO(2) \\otimes SO(1,1) has been found. In isotropic case no such reference frame exists. The way to interpret both Abelian small groups in physical terms consists in factorizing corresponding Lorentz transformations into Euclidean rotations and boosts. In the context of general study of various dual symmetries in non-commutative field theory, it is demonstrated explicitly that the non-linear constitutive equations in non-commutative electrodynamics are not invariant under continuous dual rotations, instead only invariance under discrete dual transformation exists.

V. Red'kov; E. Tolkachev

2011-09-09T23:59:59.000Z

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


41

'AdS_5' Geometry Beyond Space-time and 4D Noncommutative Space-time  

E-Print Network [OSTI]

We discuss a 4D noncommutative space-time as suggested by the version of quantum (deformed) relativity which provides a classical geometry picture as an `AdS_5'. The 4D noncommutative space-time is more like a part of a phase space description, in accordance with the quantum notion -- quantum mechanics talks about only states but not configurations. The `AdS_5' picture also illustrates the classical 4D space-time is to be described as part of a bigger geometry beyond space-time at the quantum level. The radically new picture of quantum 'space-time' is expected to provide the basis for a (still to be formulated) new approach to quantum gravity with fundamental constants (quantum) hbar and Newton's constant G put at a similar level as c, the speed of light.

Otto C. W. Kong

2009-06-19T23:59:59.000Z

42

Merging electromagnetism with space-time metric  

E-Print Network [OSTI]

In the present work, it is shown that the electromagnetism may be directly associated to the four-dimensional space-time geometry. The starting point is an analysis of the geodesic equation of general relativity where it is verified that it contains implicitly the effects of the Coulomb and the Lorentz forces. Consequently, some components of the metric tensor are identified with the components of the four-vector electromagnetic potential. Then, it is constructed a low-field equation for the electromagnetism in the same structure of the Einstein field equations for the gravitation, relating the curvature of space-time to sources of charge and current density. In this framework, all the Maxwell equations are implicit. A proof of consistency with the framework of quantum mechanics is shown.

C. A. Duarte

2014-03-10T23:59:59.000Z

43

Space-Time Insight | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Office of InspectorConcentrating SolarElectric Coop, Inc Place: Missouri References: EIA FormSouthwesternSpace-Time

44

Generalised hyperbolicity in singular space-times  

E-Print Network [OSTI]

A new concept analogous to global hyperbolicity is introduced, based on test fields. It is shown that the space-times termed here ``curve integrable'' are globally hyperbolic in this new sense, and a plausibility argument is given suggesting that the result applies to shell crossing singularities. If the assumptions behind this last argument are valid, this provides an alternative route to the assertion that such singularities do not violate cosmic censorship.

C J S Clarke

1997-04-25T23:59:59.000Z

45

Radiation Beyond Four Space-Time Dimensions  

E-Print Network [OSTI]

We present a list of formulas describing classical radiation of the rank s tensor field from an accelerated point-like source in flat space-time of arbitrary even dimension d. This allows straightforward evaluating the total intensity and radiated momentum for any $s$ and $d$ algorithmically, by hands or with the help of a computer (e.g. with an attached MAPLE program). Practical application of formulas is limited, because, for s>1, the energy-momentum tensor for the point-like source is not conserved. This usually means that one cannot neglect contributions to radiation from tensions of the forces that cause acceleration of the source.

A. Mironov; A. Morozov

2007-03-09T23:59:59.000Z

46

Universal space-time codes from demultiplexed trellis codes  

E-Print Network [OSTI]

and A. R. Calderbank, “Space-time codes for high data ratePerformance criteria and code construction,” IEEE Trans.of space–time trellis codes,” IEEE Trans. Commun. , vol. 51,

Kose, Cenk; Wesel, R D

2006-01-01T23:59:59.000Z

47

Photon tunneling in the warp drive space-time  

E-Print Network [OSTI]

We simplify the warp drive space-time such that it becomes stationary and the distorsion becomes one-dimensional and static. We use this simplified space-time as the classical background space-time for a photon field. The Drummond&Hathrell action is then used in order to investigate the velocity effects on photons tunneling through the space-time distorsion. We speculate on whether or not all tunneling processes with photons induce faster than light effects.

Cramer, C R

1995-01-01T23:59:59.000Z

48

Spinorial space-time and privileged space direction (I)  

E-Print Network [OSTI]

Spinorial space-time and privileged space direction (I) Luis Gonzalez-Mestres Abstract Contrary of a privileged space direction are not strange phenomena from the point of view of fundamental space-time geometry. As already emphasized in our previous papers on the subject, the spinorial space-time we

Paris-Sud XI, Université de

49

On Space-Time Singularities, Holes, and Extensions  

E-Print Network [OSTI]

On Space-Time Singularities, Holes, and Extensions John Byron Manchak*y Here, we clarify the relationship among three space-time conditions of interest: geodesic completeness, hole. In what follows, we consider three space-time conditions of interest: geodesic completeness, hole

Manchak, John

50

Beyond Archimedean Space-Time Structure  

SciTech Connect (OSTI)

It took two millennia after Euclid and until in the early 1880s, when we went beyond the ancient axiom of parallels, and inaugurated geometries of curved spaces. In less than one more century, General Relativity followed. At present, physical thinking is still beheld by the yet deeper and equally ancient Archimedean assumption. In view of that, it is argued with some rather easily accessible mathematical support that Theoretical Physics may at last venture into the non-Archimedean realms. In this introductory paper we stress two fundamental consequences of the non-Archimedean approach to Theoretical Physics: one of them for quantum theory and another for relativity theory. From the non-Archimedean viewpoint, the assumption of the existence of minimal quanta of light (of the fixed frequency) is an artifact of the present Archimedean mathematical basis of quantum mechanics. In the same way the assumption of the existence of the maximal velocity, the velocity of light, is a feature of the real space-time structure which is fundamentally Archimedean. Both these assumptions are not justified in corresponding non-Archimedean models.

Rosinger, Elemer E. [Department of Mathematics and Applied Mathematics, University of Pretoria, Pretoria, 0002 (South Africa); Khrennikov, Andrei [International Center for Mathematical Modeling, in Physics and Cognitive Sciences, Linnaeus University, S-35195, Vaexjoe (Sweden)

2011-03-28T23:59:59.000Z

51

Spinor structure and internal symmetries  

E-Print Network [OSTI]

Space-time and internal symmetries are considered within one theoretical framework based on the generalized spin and abstract Hilbert space. Complex momentum is understood as a generating kernel of the underlying spinor structure. It is shown that tensor products of biquaternion algebras are associated with the each irreducible representation of the Lorentz group. Space-time discrete symmetries $P$, $T$ and their combination $PT$ are generated by the fundamental automorphisms of this algebraic background (Clifford algebras). Charge conjugation $C$ is presented by a pseudoautomorphism of the complex Clifford algebra. This description of the operation $C$ allows one to distinguish charged and neutral particles including particle-antiparticle interchange and truly neutral particles. Quotient representations of the Lorentz group and their possible relations with $P$- and $CP$-violations are considered. Spin and charge multiplets, based on the interlocking representations of the Lorentz group, are introduced. A central point of the work is a correspondence between Wigner definition of elementary particle as an irreducible representation of the Poincar\\'{e} group and $SU(3)$-description (quark scheme) of the particle as a vector of the supermultiplet (irreducible representation of $SU(3)$). This correspondence is realized on the ground of a spin-charge Hilbert space. Basic hadron supermultiplets of $SU(3)$-theory (baryon octet and two meson octets) are studied in this framework. It is shown that quark phenomenologies are naturally incorporated into presented scheme. The relationship between mass and spin allows one to take a new look at the problem of mass spectrum of elementary particles.

V. V. Varlamov

2014-09-04T23:59:59.000Z

52

A Survey on Space-Time Turbo Codes  

E-Print Network [OSTI]

As wireless communication systems look intently to compose the transition from voice communication to interactive Internet data, achieving higher bit rates becomes both increasingly desirable and challenging. Space-time coding (STC) is a communications technique for wireless systems that inhabit multiple transmit antennas and single or multiple receive antennas. Space-time codes make use of advantage of both the spatial diversity provided by multiple antennas and the temporal diversity available with time-varying fading. Space-time codes can be divided into block codes and trellis codes. Space-time trellis coding merges signal processing at the receiver with coding techniques appropriate to multiple transmit antennas. The advantages of space-time codes (STC) make it extremely remarkable for high-rate wireless applications. Initial STC research efforts focused on narrowband flat-fading channels. The decoding complexity of Space-time turbo codes STTC increases exponentially as a function of the diversity level ...

Seshaiah, C V

2010-01-01T23:59:59.000Z

53

Hierarchical Bayesian models for space-time air pollution data  

E-Print Network [OSTI]

Hierarchical Bayesian models for space-time air pollution data Sujit K. Sahu June 14, 2011 sets have led to a step change in the analysis of space-time air pollution data. Accurate predictions-time air pollution data and illustrate the benefits of modeling with a real data example on monitoring

Sahu, Sujit K

54

Turbo Space-Time Codes with Time Varying Linear Transformations  

E-Print Network [OSTI]

1 Turbo Space-Time Codes with Time Varying Linear Transformations Hangjun Chen and Alexander 07102 Email: {hangjun.chen; alexander.m.haimovich}@njit.edu Abstract Turbo space-time codes with symbols in this paper. It is shown that turbo codes with TVLT achieve full diversity gain and do not require exhaustive

Haimovich, Alexander

55

BLIND RECOGNITION OF LINEAR SPACE TIME BLOCK CODES Vincent Choqueuse  

E-Print Network [OSTI]

BLIND RECOGNITION OF LINEAR SPACE TIME BLOCK CODES Vincent Choqueuse E3 I2 , EA 3876, ENSIETA 2 6165, UBO 6, avenue le Gorgeu, 29200 Brest Cedex 3 FRANCE ABSTRACT The blind recognition. In this paper, we investigate the problem of the blind recognition of Linear Space-Time Block Codes (STBC

Paris-Sud XI, Université de

56

Wick rotation for quantum field theories on degenerate Moyal space(-time)  

SciTech Connect (OSTI)

In this paper the connection between quantum field theories on flat noncommutative space(-times) in Euclidean and Lorentzian signature is studied for the case that time is still commutative. By making use of the algebraic framework of quantum field theory and an analytic continuation of the symmetry groups which are compatible with the structure of Moyal space, a general correspondence between field theories on Euclidean space satisfying a time zero condition and quantum field theories on Moyal Minkowski space is presented ('Wick rotation'). It is then shown that field theories transferred to Moyal space(-time) by Rieffel deformation and warped convolution fit into this framework, and that the processes of Wick rotation and deformation commute.

Grosse, Harald; Lechner, Gandalf [Department of Physics, University of Vienna, 1090 Vienna (Austria)] [Department of Physics, University of Vienna, 1090 Vienna (Austria); Ludwig, Thomas [Max-Planck-Institute for Mathematics in the Sciences, 04103 Leipzig (Germany) [Max-Planck-Institute for Mathematics in the Sciences, 04103 Leipzig (Germany); Institute for Theoretical Physics, University of Leipzig, 04009 Leipzig (Germany); Verch, Rainer [Institute for Theoretical Physics, University of Leipzig, 04009 Leipzig (Germany)] [Institute for Theoretical Physics, University of Leipzig, 04009 Leipzig (Germany)

2013-02-15T23:59:59.000Z

57

Condensation and evolution of space-time network  

E-Print Network [OSTI]

In this work, we try to propose, in a novel way using the Bose and Fermi quantum network approach, a framework studying condensation and evolution of space time network described by the Loop quantum gravity. Considering quantum network connectivity features in the Loop quantum gravity, we introduce a link operator, and through extending the dynamical equation for the evolution of quantum network posed by Ginestra Bianconi to an operator equation, we get the solution of the link operator. This solution is relevant to the Hamiltonian of the network, and then is related to the energy distribution of network nodes. Showing that tremendous energy distribution induce huge curved space-time network, may have space time condensation in high-energy nodes. For example, in the black hole circumstances, quantum energy distribution is related to the area, thus the eigenvalues of the link operator of the nodes can be related to quantum number of area, and the eigenvectors are just the spin network states. This reveals that the degree distribution of nodes for space-time network is quantized, which can form the space-time network condensation. The black hole is a sort of result of space-time network condensation, however there may be more extensive space-time network condensation, for example, the universe singularity (big bang).

Bi Qiao

2008-09-29T23:59:59.000Z

58

Space--time fluctuations and the spreading of wavepackets  

E-Print Network [OSTI]

Using a density matrix description in space we study the evolution of wavepackets in a fluctuating space-time background. We assume that space-time fluctuations manifest as classical fluctuations of the metric. From the non-relativistic limit of a non-minimally coupled Klein-Gordon equation we derive a Schr\\"odinger equation with an additive gaussian random potential. This is transformed into an effective master equation for the density matrix. The solutions of this master equation allow to study the dynamics of wavepackets in a fluctuating space-time, depending on the fluctuation scenario. We show how different scenarios alter the diffusion properties of wavepackets.

E. Göklü; C. Lämmerzahl; A. Camacho; A. Macias

2009-08-03T23:59:59.000Z

59

Distributed Space-Time Cooperative Schemes for Underwater Acoustic Communications  

E-Print Network [OSTI]

Distributed Space-Time Cooperative Schemes for Underwater Acoustic Communications Madhavan, which is a main characteristic of underwater acoustic channels. A time-reversal distributed space in oceanic research, such as [3] [4]: data collec- tion, pollution monitoring, tactical surveillance

Stojanovic, Milica

60

Geodesic structure of Janis-Newman-Winicour space-time  

E-Print Network [OSTI]

In the present paper we study the geodesic structure of the Janis-Newman-Winicour(JNW) space-time which contains a strong curvature naked singularity. This metric is an extension of the Schwarzschild geometry when a massless scalar field is included. We find that the strength parameter $\\mu$ of the scalar field effects on the geodesic structure of the JNW space-time. By solving the geodesic equation and analyzing the behavior of effective potential, we investigate all geodesic types of the test particle and the photon in the JNW space-time. At the same time we simulate all the geodesic orbits corresponding to the energy levels of the effective potential in the JNW space-time.

Sheng Zhou; Ruanjing Zhang; Juhua Chen; Yongjiu Wang

2014-08-26T23:59:59.000Z

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


61

Electrodynamics on {kappa}-Minkowski space-time  

SciTech Connect (OSTI)

In this paper, we derive Lorentz force and Maxwell's equations on kappa-Minkowski space-time up to the first order in the deformation parameter. This is done by elevating the principle of minimal coupling to noncommutative space-time. We also show the equivalence of minimal coupling prescription and Feynman's approach. It is shown that the motion in kappa space-time can be interpreted as motion in a background gravitational field, which is induced by this noncommutativity. In the static limit, the effect of kappa deformation is to scale the electric charge. We also show that the laws of electrodynamics depend on the mass of the charged particle, in kappa space-time.

Harikumar, E.; Juric, T.; Meljanac, S. [School of Physics, University of Hyderabad, Central University P O, Hyderabad, AP, PIN 500046 (India); Rudjer Boskovic Institute, Bijenicka c.54, HR-10002 Zagreb (Croatia)

2011-10-15T23:59:59.000Z

62

Bose-Einstein condensation in the Rindler space-time  

E-Print Network [OSTI]

We analyze the critical acceleration of the Bose-Einstein condensation induced by the Unruh effect in a complex scalar field at the finite density in the Rindler space-time.

Takeuchi, Shingo

2015-01-01T23:59:59.000Z

63

Photon propagation in a stationary warp drive space-time  

E-Print Network [OSTI]

We simplify the warp drive space-time so that it becomes stationary and the distorsion becomes one-dimensional and static. We use this simplified warp drive space-time as a background for a photon field. We shall especially use the Drummond\\&Hathrell action in order to investigate the velocity effects on photons in this background. Finally, we discuss the limitations of this model.

Claes R Cramer

1995-11-01T23:59:59.000Z

64

Fractal Relativity, Generalized Noether Theorem and New Research of Space-Time  

E-Print Network [OSTI]

First, let the fractal dimension D=n(integer)+d(decimal), so the fractal dimensional matrix was represented by a usual matrix adds a special decimal row (column). We researched that mathematics, for example, the fractal dimensional linear algebra, and physics may be developed to fractal and the complex dimension extended from fractal. From this the fractal relativity is discussed, which connects with self-similarity Universe and the extensive quantum theory. The space dimension has been extended from real number to superreal and complex number. Combining the quaternion, etc., the high dimensional time is introduced. Such the vector and irreversibility of time are derived. Then the fractal dimensional time is obtained, and space and time possess completely symmetry. It may be constructed preliminarily that the higher dimensional, fractal, complex and supercomplex space-time theory covers all. We propose a generalized Noether theorem, and irreversibility of time should correspond to non-conservation of a certain quantity. Resumed reversibility of time and possible decrease of entropy are discussed. Finally, we obtain the quantitative relations between energy-mass and space-time, which is consistent with the space-time uncertainty relation in string theory.

Yi-Fang Chang

2007-07-02T23:59:59.000Z

65

Galactic space-times in modified theories of gravity  

E-Print Network [OSTI]

We study Bertrand space-times (BSTs), which have been proposed as viable models of space-times seeded by galactic dark matter, in modified theories of gravity. We first critically examine the issue of galactic rotation curves in General Relativity, and establish the usefulness of BSTs to fit experimental data in this context. We then study BSTs in metric $f(R)$ gravity and in Brans-Dicke theories. For the former, the nature of the Newtonian potential is established, and we also compute the effective equation of state and show that it can provide good fits to some recent experimental results. For the latter, we calculate the Brans-Dicke scalar analytically in some limits and numerically in general, and find interesting constraints on the parameters of the theory. Our results provide evidence for the physical nature of Bertrand space-times in modified theories of gravity.

Dipanjan Dey; Kaushik Bhattacharya; Tapobrata Sarkar

2014-07-01T23:59:59.000Z

66

Space-Time Curvature Signatures in Bose-Einstein Condensates  

E-Print Network [OSTI]

We derive a generalized Gross-Pitaevski (GP) equation immersed on a electromagnetic and a weak gravitational field starting from the covariant Complex Klein-Gordon field in a curved space-time. We compare it with the GP equation where the gravitational field is added by hand as an external potential. We show that there is a small difference of order $g z/c^2$ between them that could be measured in the future using Bose-Einstein Condensates (BEC). This represents the next order correction to the Newtonian gravity in a curved space-time.

Matos, Tonatiuh

2015-01-01T23:59:59.000Z

67

Global geometry of space-time with the charged shell  

E-Print Network [OSTI]

It is elaborated the complete classification of the possible types of the spherically symmetric global geometries for two types of electrically charged shells: (1) The charged shell as a single source of the gravitational field, when internal space-time is flat, and external space-time is the Reissner--Nordstr\\"om metric; (2) The neutralizing shell with an electric charge opposite to the charge of the internal source with the Reissner--Nordstr\\"om metric and with the Schwarzschild metric outside the shell.

V. A. Berezin; V. I. Dokuchaev

2014-04-10T23:59:59.000Z

68

Generalised hyperbolicity in space-times with conical singularities  

E-Print Network [OSTI]

It is shown that the space-time with a conical singularity, which describes a thin cosmic string, is hyperbolic in the sense that a unique H^1 solution exists to the initial value problem for the wave equation with a certain class of initial data.

J. P. Wilson

2000-01-25T23:59:59.000Z

69

Electromagnetic space-time crystals. II. Fractal computational approach  

E-Print Network [OSTI]

A fractal approach to numerical analysis of electromagnetic space-time crystals, created by three standing plane harmonic waves with mutually orthogonal phase planes and the same frequency, is presented. Finite models of electromagnetic crystals are introduced, which make possible to obtain various approximate solutions of the Dirac equation. A criterion for evaluating accuracy of these approximate solutions is suggested.

G. N. Borzdov

2014-10-20T23:59:59.000Z

70

Space time coded code division multiplexing on SC140 DSP  

E-Print Network [OSTI]

The aim of this research is to design a high data rate wireless communication system for multi-path fading channels. Code-division multiplexing is proposed as a modulation scheme for a space-time coded multiple antenna system that would guarantee...

Menon, Murali P

2001-01-01T23:59:59.000Z

71

UCLA space-time area law model: A persuasive foundation for hadronization  

E-Print Network [OSTI]

UCLA-HEP-06-001 UCLA space-time area law model: A persuasivedominantly controlled by a Space- Time Area Law (“STAL”), anheavy quarks whose classical space-time world-lines deviate

Abachi, S; Buchanan, C; Chien, A; Chun, S; Hartfiel, B

2007-01-01T23:59:59.000Z

72

E-Print Network 3.0 - axially symmetric space-times Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Sciences and Ecology ; Mathematics 19 Hyperelliptic curve of arbitrary genus in geodesic equations Summary: constant axial symmetric space-times Taub-NUT space-time: mass...

73

Propagation of Test Particles and Scalar Fields on a Class of Wormhole Space-Times  

E-Print Network [OSTI]

In this paper, we consider the problem of test particles and test scalar fields propagating on the background of a class of wormhole space-times. For test particles, we solve for arbitrary causal geodesics in terms of integrals which are solved numerically. These integrals are parametrized by the radius and shape of the wormhole throat as well as the initial conditions of the geodesic trajectory. In terms of these parameters, we compute the conditions for the geodesic to traverse the wormhole, to be reflected by the wormhole's potential or to be captured on an unstable bound orbit at the wormhole's throat. These causal geodesics are visualized by embedding plots in Euclidean space in cylindrical coordinates. For test scalar fields, we compute transmission coefficients and quasi-normal modes for arbitrary coupling of the field to the background geometry in the WKB approximation. We show that there always exists an unstable mode whenever the coupling constant is greater than 1/2. This analysis is interesting since recent computations of self-interactions of a static scalar field in wormhole space-times reveal some anomalous dependence on the coupling constant, principally, the existence of an infinite discrete set of poles. We show that this pathological behavior of the self-field is an artifact of computing the interaction for values of the coupling constant that do not lie in the domain of stability.

Peter Taylor

2014-08-18T23:59:59.000Z

74

Entropy of Quantum Fields in de Sitter Space-time  

E-Print Network [OSTI]

The quantum states or Hilbert spaces for the quantum field theory in de Sitter space-time are studied on ambient space formalism. In this formalism, the quantum states are only depended $(1)$ on the topological character of the de Sitter space-time, {\\it i.e.} $\\R \\times S^3$, and $(2)$ on the homogeneous spaces which are used for construction of the unitary irreducible representation of de Sitter group. A compact homogeneous space is chosen in this paper. The unique feature of this homogeneous space is that its total number of quantum states, ${\\cal N}$, is finite although the Hilbert space has infinite dimensions. It is shown that ${\\cal N}$ is a continuous function of the Hubble constant $H$ and the eigenvalue of the Casimir operators of de Sitter group. The entropy of the quantum fields on this Hilbert space have been calculated which is finite and invariant for all inertial observers on the de Sitter hyperboloid.

M. V. Takook

2014-08-15T23:59:59.000Z

75

Noncommutative of space-time and the relativistic Hydrogen atom  

E-Print Network [OSTI]

We study the Klein-Gordon equation in a non-commutative space-time as applied to the Hydrogen atom to extract the energy levels, by considering the second-order corrections in the non-commutativity paramete and by comparing to the 2S - 1S transition accuracy we get a bound on the parameter of noncommutativity. Phenomenologically we show that non-commutativity is the source of lamb shift corrections and spin electron.

Slimane Zaim; Yazid Delenda

2012-12-02T23:59:59.000Z

76

The wave equation on static singular space-times  

E-Print Network [OSTI]

The first part of my thesis lays the foundations to generalized Lorentz geometry. The basic algebraic structure of finite-dimensional modules over the ring of generalized numbers is investigated. The motivation for this part of my thesis evolved from the main topic, the wave equation on singular space-times. The second and main part of my thesis is devoted to establishing a local existence and uniqueness theorem for the wave equation on singular space-times. The singular Lorentz metric subject to our discussion is modeled within the special algebra on manifolds in the sense of Colombeau. Inspired by an approach to generalized hyperbolicity of conical-space times due to Vickers and Wilson, we succeed in establishing certain energy estimates, which by a further elaborated equivalence of energy integrals and Sobolev norms allow us to prove existence and uniqueness of local generalized solutions of the wave equation with respect to a wide class of generalized metrics. The third part of my thesis treats three different point value resp. uniqueness questions in algebras of generalized functions

Eberhard Mayerhofer

2008-02-12T23:59:59.000Z

77

Relativistic helicity and link in Minkowski space-time  

SciTech Connect (OSTI)

A relativistic helicity has been formulated in the four-dimensional Minkowski space-time. Whereas the relativistic distortion of space-time violates the conservation of the conventional helicity, the newly defined relativistic helicity conserves in a barotropic fluid or plasma, dictating a fundamental topological constraint. The relation between the helicity and the vortex-line topology has been delineated by analyzing the linking number of vortex filaments which are singular differential forms representing the pure states of Banach algebra. While the dimension of space-time is four, vortex filaments link, because vorticities are primarily 2-forms and the corresponding 2-chains link in four dimension; the relativistic helicity measures the linking number of vortex filaments that are proper-time cross-sections of the vorticity 2-chains. A thermodynamic force yields an additional term in the vorticity, by which the vortex filaments on a reference-time plane are no longer pure states. However, the vortex filaments on a proper-time plane remain to be pure states, if the thermodynamic force is exact (barotropic), thus, the linking number of vortex filaments conserves.

Yoshida, Z.; Kawazura, Y. [Graduate School of Frontier Sciences, University of Tokyo, Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan)] [Graduate School of Frontier Sciences, University of Tokyo, Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Yokoyama, T. [Department of Mathematics, Hokkaido University, Kita 10, Nishi 8, Kita-Ku, Sapporo, Hokkaido 060-0810 (Japan)] [Department of Mathematics, Hokkaido University, Kita 10, Nishi 8, Kita-Ku, Sapporo, Hokkaido 060-0810 (Japan)

2014-04-15T23:59:59.000Z

78

Fradkin-Bacry-Ruegg-Souriau vector in kappa-deformed space-time  

E-Print Network [OSTI]

We study presence of an additional symmetry of a generic central potential in the $\\kappa$-space-time. An explicit construction of Fradkin and Bacry, Ruegg, Souriau (FBRS) for a central potential is carried out and the piece-wise conserved nature of the vector is established. We also extend the study to Kepler systems with a drag term, particularly Gorringe-Leach equation is generalized to the $\\kappa$-deformed space. The possibility of mapping Gorringe-Leach equation to an equation with out drag term is exploited in associating a similar conserved vector to system with a drag term. An extension of duality between two class of central potential is introduced in the $\\kappa$-deformed space and is used to investigate the duality existing between two class of Gorringe-Leach equations. All the results obtained can be retraced to the correct commutative limit as we let $a \\rightarrow 0$.

Guha, Partha; S, Zuhair N

2015-01-01T23:59:59.000Z

79

Tolman-Bondi Space-Time in Brane World Scenario  

E-Print Network [OSTI]

In the present work, inhomogeneous Tolman-Bondi type dust space-time is studied on the brane. There are two sets of solutions of the above model. The first solution represents either a collapsing model starting from an infinite volume at infinite past to the singularity or a model starting from a singularity and expanding for ever having a transition from decelerating phase to accelerating phase. The first solution shows that the end state of collapse may be black hole or a naked singularity depending signs of various parameters involved. The second solution represents a bouncing model where the bounce occurs at different comoving radii at different epochs.

Subenoy Chakraborty; Asit Banerjee; Ujjal Debnath

2006-02-17T23:59:59.000Z

80

Bounds on negative energy densities in static space-times  

E-Print Network [OSTI]

Certain exotic phenomena in general relativity, such as backward time travel, appear to require the presence of matter with negative energy. While quantum fields are a possible source of negative energy densities, there are lower bounds - known as quantum inequalities - that constrain their duration and magnitude. In this paper, we derive new quantum inequalities for scalar fields in static space-times, as measured by static observers with a choice of sampling function. Unlike those previously derived by Pfenning and Ford, our results do not assume any specific sampling function. We then calculate these bounds in static three- and four-dimensional Robertson-Walker universes, the de Sitter universe, and the Schwarzschild black hole. In each case, the new inequality is stronger than that of Pfenning and Ford for their particular choice of sampling function.

Christopher J. Fewster; Edward Teo

1999-02-16T23:59:59.000Z

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


81

Photon Green Functions in Curved Space-Time  

E-Print Network [OSTI]

Quantization of electrodynamics in curved space-time in the Lorenz gauge and with arbitrary gauge parameter makes it necessary to study Green functions of non-minimal operators with variable coefficients. Starting from the integral representation of photon Green functions, we link them to the evaluation of integrals involving Gamma-functions. Eventually, the full asymptotic expansion of the Feynman photon Green function at small values of the world function, as well as its explicit dependence on the gauge parameter, are obtained without adding by hand a mass term to the Faddeev-Popov Lagrangian. Coincidence limits of second covariant derivatives of the associated Hadamard function are also evaluated, as a first step towards the energy-momentum tensor in the non-minimal case.

Giuseppe Bimonte; Enrico Calloni; Luciano Di Fiore; Giampiero Esposito; Leopoldo Milano; Luigi Rosa

2005-11-23T23:59:59.000Z

82

Effects of quantum space time foam in the neutrino sector  

E-Print Network [OSTI]

We discuss violations of CPT and quantum mechanics due to interactions of neutrinos with space-time quantum foam. Neutrinoless double beta decay and oscillations of neutrinos from astrophysical sources (supernovae, active galactic nuclei) are analysed. It is found that the propagation distance is the crucial quantity entering any bounds on EHNS parameters. Thus, while the bounds from neutrinoless double beta decay are not significant, the data of the supernova 1987a imply a bound being several orders of magnitude more stringent than the ones known from the literature. Even more stringent limits may be obtained from the investigation of neutrino oscillations from active galactic nuclei sources, which have an impressive potential for the search of quantum foam interactions in the neutrino sector.

H. V. Klapdor-Kleingrothaus; H. Päs; U. Sarkar

2000-07-05T23:59:59.000Z

83

E-Print Network 3.0 - additive space-time white Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

space-time white Search Powered by Explorit Topic List Advanced Search Sample search results for: additive space-time white Page: << < 1 2 3 4 5 > >> 1 Click to Submit...

84

Geometry of Majorana neutrino and new symmetries  

E-Print Network [OSTI]

Experimental observation of Majorana fermion matter gives a new impetus to the understanding of the Lorentz symmetry and its extension, the geometrical properties of the ambient space-time structure, matter--antimatter symmetry and some new ways to understand the baryo-genesis problem in cosmology. Based on the primordial Majorana fermion matter assumption, we discuss a possibility to solve the baryo-genesis problem through the the Majorana-Diraco genesis in which we have a chance to understand creation of Q(em) charge and its conservation in our D=1+3 Universe after the Big Bang. In the Majorana-Diraco genesis approach there appears a possibility to check the proton and electron non-stability on the very low energy scale. In particle physics and in our space-time geometry, the Majorana nature of the neutrino can be related to new types of symmetries which are lying beyond the binary Cartan-Killing-Lie algebras/superalgebras. This can just support a conjecture about the non-completeness of the SM in terms of binary Cartan--Killing--Lie symmetries/supersymmetries. As one of the very important applications of such new ternary symmetries could be related with explanation of the nature of the three families and three colour symmetry. The Majorana neutrino can directly indicate the existence of a new extra-dimensional geometry and thanks to new ternary space-time symmetries, could lead at high energies to the unextraordinary phenomenological consequences.

G. G. Volkov

2006-07-30T23:59:59.000Z

85

SPACE-TIME BLOCK CODING : JOINT DETECTION AND CHANNEL ESTIMATION USING MULTIPLE MODEL THEORY  

E-Print Network [OSTI]

SPACE-TIME BLOCK CODING : JOINT DETECTION AND CHANNEL ESTIMATION USING MULTIPLE MODEL THEORY Harini of Sheffield, Mappin Street, Sheffield S1 3JD. Email: visakan@sheffield.ac.uk ABSTRACT A joint decoding method for space-time block codes [1, 2] is pre- sented. The space-time coded signals can be viewed as a first

Imperial College, London

86

Space-Time Turbo Codes Youjian Liu and Michael P. Fitz  

E-Print Network [OSTI]

Space-Time Turbo Codes Youjian Liu and Michael P. Fitz Department of Electrical Engineering. We propose a new class of scalable space{time codes based on turbo codes or turbo trellis codes 1]. They will be referred as space{time turbo codes (STT) in the sequel. The scalability implies that the code rate

Liu, Youjian "Eugene"

87

Space-Time Turbo Code Using Quantized Feedback with Two Transmit Antennas  

E-Print Network [OSTI]

Space-Time Turbo Code Using Quantized Feedback with Two Transmit Antennas Chi Hoon Yoo and Jae Hong-time turbo code with two transmit antennas in a quasi- static Rayleigh fading channel. The performance for the space-time turbo code. To improve the perform- ance of the space-time turbo code, we propose the new

Lee, Jae Hong

88

LINEAR SPACE-TIME PRECODING FOR RICIAN FADING MISO CHANNELS Mai Vu, Arogyaswami Paulraj  

E-Print Network [OSTI]

LINEAR SPACE-TIME PRECODING FOR RICIAN FADING MISO CHANNELS Mai Vu, Arogyaswami Paulraj Stanford, Australia Email: r.evans@ee.mu.oz.au ABSTRACT We study a space-time precoding technique for MISO wire- less in practice. In this paper, we study a particular space-time coding scheme with memory for Rician MISO

Vu, Mai

89

The Euclid space-time diagram of the theory of relativity  

E-Print Network [OSTI]

A conventional space-time diagram is $r-ct$ one, which satisfies the Minkowski geometry. This geometry conflict the intuition from the Euclid geometry. In this work an Euclid space-time diagram is proposed to describe relativistic world lines with an exact Euclid geometry. The relativistic effects such as the dilation of moving clocks, the contraction of moving length, and the twin paradox can be geometrically expressed in the Euclid space-time diagram. It is applied to the case of a satellite clock to correct the gravitational effect. It is found that this Euclid space-time diagram is much more intuitive than the conventional space-time diagram.

W. LiMing

2014-06-03T23:59:59.000Z

90

Majorana-Oppenheimer approach to Maxwell electrodynamics in Riemannian space-time  

E-Print Network [OSTI]

The Riemann -- Silberstein -- Majorana -- Oppengeimer approach to the Maxwell electrodynamics in presence of electrical sources and arbitrary media is investigated within the matrix formalism. The symmetry of the matrix Maxwell equation under transformations of the complex rotation group SO(3.C) is demonstrated explicitly. In vacuum case, the matrix form includes four real $4 \\times 4$ matrices $\\alpha^{b}$. In presence of media matrix form requires two sets of $4 \\times 4$ matrices, $\\alpha^{b}$ and $\\beta^{b}$ -- simple and symmetrical realization of which is given. Relation of $\\alpha^{b}$ and $\\beta^{b}$ to the Dirac matrices in spinor basis is found. Minkowski constitutive relations in case of any linear media are given in a short algebraic form based on the use of complex 3-vector fields and complex orthogonal rotations from SO(3.C) group. The matrix complex formulation in the Esposito's form, based on the use of two electromagnetic 4-vector, is studied and discussed. Extension of the 3-vector complex matrix formalism to arbitrary Riemannian space-time in accordance with tetrad method by Tetrode-Weyl-Fock-Ivanenko is performed.

A. Bogush; V. Red'kov; N. Tokarevskaya; G. Spix

2009-05-03T23:59:59.000Z

91

Quasi-orthogonal space-frequency and space-time-frequency block codes for MIMO OFDM channels  

E-Print Network [OSTI]

Lu and X. Wang, “Space-time code design in OFDM systems,” inSpace-time block codes from orthogonal designs,” IEEE Trans.orthogonal space- time block codes with full diversity,”

Fazel, Fatemeh; Jafarkhani, Hamid

2008-01-01T23:59:59.000Z

92

Discrete dark matter  

SciTech Connect (OSTI)

We propose a new motivation for the stability of dark matter (DM). We suggest that the same non-Abelian discrete flavor symmetry which accounts for the observed pattern of neutrino oscillations, spontaneously breaks to a Z{sub 2} subgroup which renders DM stable. The simplest scheme leads to a scalar doublet DM potentially detectable in nuclear recoil experiments, inverse neutrino mass hierarchy, hence a neutrinoless double beta decay rate accessible to upcoming searches, while {theta}{sub 13}=0 gives no CP violation in neutrino oscillations.

Hirsch, M.; Morisi, S.; Peinado, E.; Valle, J. W. F. [AHEP Group, Institut de Fisica Corpuscular--C.S.I.C./Universitat de Valencia, Edificio Institutos de Paterna, Apartado 22085, E-46071 Valencia (Spain)

2010-12-01T23:59:59.000Z

93

Well-posedness of the Space-Time Fractional Diffusion Problems ...  

E-Print Network [OSTI]

... and dynamics of a bead in polymer network, and so on. In this talk, we consider initial boundary value problems of the space-time fractional diffusion equation ...

94

Non-marginally bound inhomogeneous dust collapse in higher dimensional space-time  

E-Print Network [OSTI]

We investigate the occurrence and nature of a naked singularity in the gravitational collapse of an inhomogeneous dust cloud described by a self-similar higher dimensional Tolman-Bondi space-time. Bound, marginally bound and unbound space-times are analyzed. The degree of inhomogeneity of the collapsing matter necessary to form a naked singularity is given.

S. G. Ghosh; A. Banerjee

2002-12-16T23:59:59.000Z

95

Alamouti Space Time Coded OFDM for Underwater Acoustic Channels Baosheng Li1  

E-Print Network [OSTI]

the time-variation of the channel. Adaptive channel estimation for space-time block coded (STBC) OFDM], [11]. Reference [9] discusses a jointly optimized MIMO-DFE with space- time trellis codes. In [10 stay fixed over the duration of one OFDM block, but may change from one block to another. Channel

Stojanovic, Milica

96

Topological horseshoes in travelling waves of discretized nonlinear wave equations  

SciTech Connect (OSTI)

Applying the concept of anti-integrable limit to coupled map lattices originated from space-time discretized nonlinear wave equations, we show that there exist topological horseshoes in the phase space formed by the initial states of travelling wave solutions. In particular, the coupled map lattices display spatio-temporal chaos on the horseshoes.

Chen, Yi-Chiuan, E-mail: YCChen@math.sinica.edu.tw [Institute of Mathematics, Academia Sinica, Taipei 10617, Taiwan (China)] [Institute of Mathematics, Academia Sinica, Taipei 10617, Taiwan (China); Chen, Shyan-Shiou, E-mail: sschen@ntnu.edu.tw [Department of Mathematics, National Taiwan Normal University, Taipei 11677, Taiwan (China)] [Department of Mathematics, National Taiwan Normal University, Taipei 11677, Taiwan (China); Yuan, Juan-Ming, E-mail: jmyuan@pu.edu.tw [Department of Financial and Computational Mathematics, Providence University, Shalu, Taichung 43301, Taiwan (China)] [Department of Financial and Computational Mathematics, Providence University, Shalu, Taichung 43301, Taiwan (China)

2014-04-15T23:59:59.000Z

97

Quantum estimation of the Schwarzschild space-time parameters of the Earth  

E-Print Network [OSTI]

We propose a quantum experiment to measure with high precision the Schwarzschild space-time parameters of the Earth. The scheme can also be applied to measure distances by taking into account the curvature of the Earth's space-time. As a wave-packet of (entangled) light is sent from the Earth to a satellite it is red-shifted and deformed due to the curvature of space-time. Measurements after the propagation enable the estimation of the space-time parameters. We compare our results with the state of the art, which involves classical measurement methods, and discuss what developments are required in space-based quantum experiments to improve on the current measurement of the Schwarzschild radius of the Earth.

David Edward Bruschi; Animesh Datta; Rupert Ursin; Timothy C. Ralph; Ivette Fuentes

2014-08-31T23:59:59.000Z

98

Space-time resolved electrokinetics in cylindrical and semi-cylindrical microchannels  

E-Print Network [OSTI]

It is shown show how to employ Bessel-Fourier series in order to obtain a complete space-time resolved description of electrokinetic phenomena in cylindrical and semi-cylindrical microfluidic channels.

Michele Campisi

2007-05-03T23:59:59.000Z

99

A study of Turbo Codes across Space Time Spreading Channel 1  

E-Print Network [OSTI]

This study looks at the use of Turbo Codes across a space time spreading (STS) channel in the absence of multi-path. For 3 and 5 iterations, turbo codes was shown to improve the BER by up to 3%.

Ibrahim S. Raad; Peter Vial; Tad Wysocki

100

Compatible, energy and symmetry preserving 2D Lagrangian hydrodynamics in rz-cylindrical coordinates  

SciTech Connect (OSTI)

We present a new discretization for 2D Lagrangian hydrodynamics in rz geometry (cylindrical coordinates) that is compatible, energy conserving and symmetry preserving. We describe discretization of the basic Lagrangian hydrodynamics equations.

Shashkov, Mikhail [Los Alamos National Laboratory; Wendroff, Burton [Los Alamos National Laboratory; Burton, Donald [Los Alamos National Laboratory; Barlow, A [AWE; Hongbin, Guo [ASU

2009-01-01T23:59:59.000Z

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


101

Temporal variations in space-time and progenitors of gamma ray burst and millisecond pulsars  

E-Print Network [OSTI]

A time varying space-time metric is shown to be a source of electromagnetic radiation. The post-Newtonian approximation is used as a realistic model of the connection between the space-time metric and a time varying gravitational potential. Large temporal variations in the metric from the coalescence of colliding black holes and neutron stars are shown to be possible progenitors of gamma ray burst and millisecond pulsars.

Preston Jones

2007-08-31T23:59:59.000Z

102

Improved Space-time Turbo Codes with Full Spatial Diversity over Integer Ring  

E-Print Network [OSTI]

Improved Space-time Turbo Codes with Full Spatial Diversity over Integer Ring Tae Min Kim and Jae-time turbo codes designed over integer ring for BPSK and QPSK modulation. The proposed spacetime turbo codes of 0.5 dB at FER of IO-$ over the space-time turbo codes with the iterative non-binary m a x i " D

Lee, Jae Hong

103

Semi-Blind Gradient-Newton CMA and SDD Algorithm for MIMO Space-Time Equalisation  

E-Print Network [OSTI]

Semi-Blind Gradient-Newton CMA and SDD Algorithm for MIMO Space-Time Equalisation S. Chen, L. HanzoBJ, UK. E-mails: {sqc, lh, htc1e08}@ecs.soton.ac.uk Abstract-- Semi-blind space-time equalisation-directed scheme is then applied to adapt the STE. The proposed semi-blind adaptive STE is capable of converging

Chen, Sheng

104

SPACE TIME INTERFERENCE ALIGNMENT SCHEME FOR THE MIMO BC AND IC WITH DELAYED CSIT AND FINITE COHERENCE TIME  

E-Print Network [OSTI]

and Heath, space-time interference align- ment (STIA), proves that in the underdetermined (overloaded) multi in [11] proposed a scheme, hereafter referred to as space-time interference alignment (STIA

Gesbert, David

105

High-Fidelity Space-Time Adaptive Multiphysics Simulations in Nuclear Engineering  

SciTech Connect (OSTI)

Monolithic adaptive multimesh hp-FEM discretization of multiphysics coupled problems Monolithic coupling of hp-FEM and hp-DG methods New modular approach to higher-order time discretization of transient PDE problems

Solin, Pavel; Ragusa, Jean

2014-05-21T23:59:59.000Z

106

Symmetry Energy  

E-Print Network [OSTI]

Examination of symmetry energy is carried out on the basis of an elementary binding-energy formula. Constraints are obtained on the energy value at the normal nuclear density and on the density dependence of the energy at subnormal densities.

P. Danielewicz

2006-07-15T23:59:59.000Z

107

Symmetry Energy  

E-Print Network [OSTI]

Examination of symmetry energy is carried out on the basis of an elementary binding-energy formula. Constraints are obtained on the energy value at the normal nuclear density and on the density dependence of the energy at subnormal densities.

Danielewicz, P

2006-01-01T23:59:59.000Z

108

0-7803-7442-8/02/$17.00 2002 IEEE Combined Beamforming and Space-Time Block Coding with a  

E-Print Network [OSTI]

continue our investigation of joint beamforming and transmit diversity with space-time block coding0-7803-7442-8/02/$17.00 © 2002 IEEE Combined Beamforming and Space-Time Block Coding with a Sparse or two) in conjunction with beam-space-time block coding to achieve transmit diversity. On the receiving

Morelos-Zaragoza, Robert H.

109

${\\mathbb{Z}}_N$ graded discrete Lax pairs and discrete integrable systems  

E-Print Network [OSTI]

We introduce a class of ${\\mathbb{Z}}_N$ graded discrete Lax pairs, with $N\\times N$ matrices, linear in the spectral parameter. We give a classification scheme for such Lax pairs and the associated discrete integrable systems. We present two potential forms and completely classify the generic case. Many well known examples belong to our scheme for $N=2$, so many of our systems may be regarded as generalisations of these. Even at $N=3$, several new integrable systems arise. Many of our equations are mutually compatible, so can be used together to form "coloured" lattices. We also present continuous isospectral deformations of our Lax pairs, giving compatible differential-difference systems, which play the role of continuous symmetries of our discrete systems. We present master symmetries and a recursive formulae for their respective hierarchies, for the generic case. We present two nonlocal symmetries of our discrete systems, which have a natural representation in terms of the potential forms. These give rise to the two-dimensional Toda lattice, with our nonlinear symmetries being the B\\"acklund transformations and our discrete system being the nonlinear superposition formula (for the generic case).

Allan P. Fordy; Pavlos Xenitidis

2014-11-22T23:59:59.000Z

110

Conservation Laws and Non-Lie Symmetries  

E-Print Network [OSTI]

We introduce a method to construct conservation laws for a large class of linear partial differential equations. In contrast to the classical result of Noether, the conserved currents are generated by any symmetry of the operator, including those of the non-Lie type. An explicit example is made of the Dirac equation were we use our construction to find a class of conservation laws associated with a 64 dimensional Lie algebra of discrete symmetries that includes CPT.

Anthony C. L Ashton

2008-10-05T23:59:59.000Z

111

Energy-momentum Prescriptions in General Spherically Symmetric Space-times  

E-Print Network [OSTI]

Einstein, Landau-Lifshitz, Papapetrou, Weinberg, and M{\\o}ller energy-momentum prescriptions in general spherically symmetric space-times are investigated. It is shown that for two special but not unusual classes of general spherically symmetric space-times several energy-momentum prescriptions in Schwarzschild Cartesian coordinates lead to some coincidences in energy distribution. It is also obtained that for a special class of spherically symmetric metrics M{\\o}ller and Einstein energy-momentum prescriptions give the same result for energy distribution if and only if it has a specific dependence on radial coordinate.

Saeed Mirshekari; Amir M. Abbassi

2014-11-29T23:59:59.000Z

112

Discrete-Gauss states and the generation of focussing dark beams  

E-Print Network [OSTI]

Discrete-Gauss states are a new class of gaussian solutions of the free Schr\\"odinger equation owning discrete rotational symmetry. They are obtained by acting with a discrete deformation operator onto Laguerre-Gauss modes. We present a general analytical construction of these states and show the necessary and sufficient condition for them to host embedded dark beams structures. We unveil the intimate connection between discrete rotational symmetry, orbital angular momentum, and the generation of focussing dark beams. The distinguishing features of focussing dark beams are discussed. The potential applications of Discrete-Gauss states in advanced optical trapping and quantum information processing are also briefly discussed.

Albert Ferrando

2014-03-25T23:59:59.000Z

113

Unitary Evolution on a Discrete Phase Space  

E-Print Network [OSTI]

We construct unitary evolution operators on a phase space with power of two discretization. These operators realize the metaplectic representation of the modular group SL(2,Z_{2^n}). It acts in a natural way on the coordinates of the non-commutative 2-torus, T_{2^n}^2$ and thus is relevant for non-commutative field theories as well as theories of quantum space-time. The class of operators may also be useful for the efficient realization of new quantum algorithms.

E. G. Floratos; S. Nicolis

2005-10-06T23:59:59.000Z

114

Using Space-Time Constraints to Guide Model Interoperability Paul F. Reynolds Jr.  

E-Print Network [OSTI]

to motion retargeting ­ accurately transferring human motions to animated characters. A typical goalUsing Space-Time Constraints to Guide Model Interoperability Paul F. Reynolds Jr. Dept of Computer-924-1039 (V) , 434-982-2214 (F) reynolds@virginia.edu Keywords: Interoperability, Multi-Resolution Modeling

Brogan, David

115

Photon emission in a constant magnetic field in 2+1 dimensional space-time  

E-Print Network [OSTI]

We calculate by the proper-time method the amplitude of the two-photon emission by a charged fermion in a constant magnetic field in (2+1)-dimensional space-time. The relevant dynamics reduces to that of a supesymmetric quantum-mechanical system with one bosonic and one fermionic degrees of freedom.

J. T. S. Amaral; S. I. Zlatev

2005-11-01T23:59:59.000Z

116

Climate Projections Using Bayesian Model Averaging and Space-Time Dependence  

E-Print Network [OSTI]

Climate Projections Using Bayesian Model Averaging and Space-Time Dependence K. Sham Bhat, Murali Haran, Adam Terando, and Klaus Keller. Abstract Projections of future climatic changes are a key input to the design of climate change mitiga- tion and adaptation strategies. Current climate change projections

Haran, Murali

117

Perturbative Approaching for Boson Fields' System in a Lewis-Papapetrou Space-Time  

SciTech Connect (OSTI)

In this paper the first order solutions of a Klein--Gordon--Maxwell--Einstein coupled system equations were derived for boson fields in a Lewis Papapetrou space time. The results expand the previous static solutions obtained in literature. A main goal is represented by the symbolic script built for such approach.

Murariu, G. [Physics Department, Faculty of Sciences, University 'Dunarea de Jos', Galati, Domneasca Street, No.111, Galati (Romania); Dariescu, M. A.; Dariescu, C. [Physics Faculty, 'Alexandru Ioan Cuza' University Iasi, Carol Bul., No.111, Iasi (Romania)

2010-08-04T23:59:59.000Z

118

XXII ICTAM, 2529 August 2008, Adelaide, Australia SPACE-TIME MEASUREMENTS OF BREAKING WAVE KINEMATICS  

E-Print Network [OSTI]

with light intensity. WAVE KINEMATICS Phase average vorticity In order to have a statistical evolutionXXII ICTAM, 25­29 August 2008, Adelaide, Australia SPACE-TIME MEASUREMENTS OF BREAKING WAVE KINEMATICS AND VOID FRACTION IN THE SURF ZONE Olivier Kimmoun1 , 2 Hubert Branger1 1IRPHE, CNRS, Aix

Paris-Sud XI, Université de

119

Powering Up With Space-Time Wind Forecasting Amanda S. HERING and Marc G. GENTON  

E-Print Network [OSTI]

Powering Up With Space-Time Wind Forecasting Amanda S. HERING and Marc G. GENTON The technology to harvest electricity from wind energy is now advanced enough to make entire cities powered by it a reality be more realistically assessed with a loss measure that depends upon the power curve relating wind speed

Genton, Marc G.

120

Time-varying Reeb Graphs for Continuous Space-Time Data Herbert Edelsbrunner  

E-Print Network [OSTI]

and/or a fee. SOCG '04 New York City, New York USA Copyright 2004 ACM ?? . . . $4.99. of dataTime-varying Reeb Graphs for Continuous Space-Time Data Herbert Edelsbrunner , John Harer , Ajith the evolving sequence into a single, partially persistent data structure. We envision this data structure

Pascucci, Valerio

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


121

Dark Energy and Tachyon Field in Bianchi Type-V Space-time  

E-Print Network [OSTI]

In this paper, we consider Bianchi type-V space-time and study a cosmological model of dark energy based on Tachyon scalar field. We assumed three different kinds of matter without possibility of interaction with scalar dark energy. Assuming power law Hubble parameter in terms of scale factor we obtain evolution of scalar field, scalar potential and equation of state parameter.

J. Sadeghi; H. Farahani

2014-04-15T23:59:59.000Z

122

Performance of Turbo Coded WCDMA with Downlink Space Time Block Coding in Correlated Fading Channels  

E-Print Network [OSTI]

Performance of Turbo Coded WCDMA with Downlink Space Time Block Coding in Correlated Fading due to potential high data rate applications such as wireless internet access. Turbo codes. In this paper, we evaluate the performance of turbo coded WCDMA systems with downlink transmit diversity

Mandayam, Narayan

123

IEEE VEHICULAR TECHNOLOGY CONFERENCE SPRING, 2003 1 Space-Time Block Coding applied to Turbo Coded  

E-Print Network [OSTI]

IEEE VEHICULAR TECHNOLOGY CONFERENCE SPRING, 2003 1 Space-Time Block Coding applied to Turbo Coded and a Turbo Code (TC) as channel code. MC-CDMA is likely to be one of the most promising access technique. Then, since Turbo Coded MC-CDMA was demonstrated to be very efficient for a Single Input Single Output

Paris-Sud XI, Université de

124

The stability of Killing-Cauchy horizons in colliding plane wave space-times  

E-Print Network [OSTI]

It is confirmed rigorously that the Killing-Cauchy horizons, which sometimes occur in space-times representing the collision and subsequent interaction of plane gravitational waves in a Minkowski background, are unstable with respect to bounded perturbations of the initial waves, at least for the case in which the initial waves have constant aligned polarizations.

J. B. Griffiths

2005-01-05T23:59:59.000Z

125

Blind Equalization and Identification for Differential Space-time Modulated Communication Systems  

E-Print Network [OSTI]

Blind Equalization and Identification for Differential Space-time Modulated Communication Systems A Thesis Presented in Partial Fulfillment of the Requirements for the Degree Master of Science of blind identification and equalization for MIMO system with frequency- selective fading channels. We

Schniter, Philip

126

THE PERFORMANCE OF SPACE-TIME CODED COOPERATIVE DIVERSITY IN AN ASYNCHRONOUS CELLULAR UPLINK  

E-Print Network [OSTI]

THE PERFORMANCE OF SPACE-TIME CODED COOPERATIVE DIVERSITY IN AN ASYNCHRONOUS CELLULAR UPLINK Kanchan G. Vardhe and Daryl Reynolds Lane Dept. of Comp. Sci. and Elect. Eng. West Virginia University Morgantown, WV kanchanv@csee.wvu.edu, darylreynolds@ieee.org ABSTRACT Most of the prior work on cooperative

Reynolds, Daryl

127

MODELING SPACE-TIME DEPENDENT HELIUM BUBBLE EVOLUTION IN TUNGSTEN ARMOR UNDER IFE CONDITIONS  

E-Print Network [OSTI]

MODELING SPACE-TIME DEPENDENT HELIUM BUBBLE EVOLUTION IN TUNGSTEN ARMOR UNDER IFE CONDITIONS Qiyang dependent Helium transport in finite geometries, including the simultaneous transient production of defects of Helium bubbles. I. INTRODUCTION Helium production and helium bubble evolution in neutron

Ghoniem, Nasr M.

128

Broken Symmetry  

ScienceCinema (OSTI)

- Physics, as we know it, attempts to interpret the diverse natural phenomena as particular manifestations of general laws. This vision of a world ruled by general testable laws is relatively recent in the history of mankind. Basically it was initiated by the Galilean inertial principle. The subsequent rapid development of large-scale physics is certainly tributary to the fact that gravitational and electromagnetic forces are long-range and hence can be perceived directly without the mediation of highly sophisticated technical devices. - The discovery of subatomic structures and of the concomitant weak and strong short-range forces raised the question of how to cope with short-range forces in relativistic quantum field theory. The Fermi theory of weak interactions, formulated in terms of point-like current-current interaction, was well-defined in lowest order perturbation theory and accounted for existing experimental data.However, it was inconsistent in higher orders because of uncontrollable divergent quantum fluctuations. In technical terms, in contradistinction to quantum electrodynamics, the Fermi theorywas not ?renormalizable?. This difficulty could not be solved by smoothing the point-like interaction by a massive, and therefore short-range, charged ?vector? particle exchange: theories with massive charged vector bosons were not renormalizable either. In the early nineteen sixties, there seemed to be insuperable obstacles to formulating a consistent theory with short-range forces mediated by massive vectors. - The breakthrough came from the notion of spontaneous symmetry breaking which arose in the study of phase transitions and was introduced in field theory by Nambu in 1960. - Ferromagnets illustrate the notion in phase transitions. Although no direction is dynamically preferred, the magnetization selects a global orientation. This is a spontaneous broken symmetry(SBS)of rotational invariance. Such continuous SBS imply the existence of ?massless? modes (here spin-waves), which are the ancestors of the NG bosons discussed below. Fluctuations of the order parameter (the magnetization) are described by a ?massive? SBS mode. - In field theory, Nambu showed that broken chiral symmetry from a spontaneous generation of hadron masses induces massless pseudoscalar modes (identified with a massless limit of pion fields). This illustrates a general phenomenon made explicit by Goldstone: massless Nambu-Goldstone (NG) bosons are a necessary concomitant of spontaneously broken continuous symmetries. Massive SBS scalars bosons describe, as in phase transitions, the fluctuations of the SBS order parameters. - In 1964, with Robert Brout, we discovered a mechanism based on SBS by which short range interactions are generated from long range ones. A similar proposal was then made independently by Higgs in a different approach. Qualitatively, our mechanism works as follows. The long range fundamental electromagnetic and gravitational interactions are governed by extended symmetries,called gauge symmetries, which were supposed to guarantee that the elementary field constituents which transmit the forces, photons or gravitons, be massless. We considered a generalization of the electromagnetic ?vector? field, known as Yang-Mills fields, and coupled them to fields which acquire from SBS constant values in the vacuum. These fields pervade space, as did magnetization, but they have no spatial orientation: they are ?scalar?? fields. The vector Yang-Mills fields which interact with the scalar fields become massive and hence the forces they mediate become short ranged. We also showed that the mechanism can survive in absence of elementary scalar fields. - Because of the extended symmetries, the nature of SBS is profoundly altered: the NG fields are absorbed into the massive vector Yang-Mills fields and restore the gauge symmetry. This has a dramatic consequence. To confront precision experiments, the mechanism should be consistent at the quantum mechanical level, or in technical terms, should yield a ?renormalizable? theory. From our analysi

None

2011-10-06T23:59:59.000Z

129

The structure of the extreme Schwarzschild-de Sitter space-time  

E-Print Network [OSTI]

The extreme Schwarzschild-de Sitter space-time is a spherically symmetric solution of Einstein's equations with a cosmological constant Lambda and mass parameter m>0 which is characterized by the condition that 9 Lambda m^2=1. The global structure of this space-time is here analyzed in detail. Conformal and embedding diagrams are constructed, and synchronous coordinates which are suitable for a discussion of the cosmic no-hair conjecture are presented. The permitted geodesic motions are also analyzed. By a careful investigation of the geodesics and the equations of geodesic deviation, it is shown that specific families of observers escape from falling into the singularity and approach nonsingular asymptotic regions which are represented by special "points" in the complete conformal diagram. The redshift of signals emitted by particles which fall into the singularity, as detected by those observers which escape, is also calculated.

J. Podolsky

1999-10-08T23:59:59.000Z

130

Space-time analysis of reactor-control rod-worth measurements  

SciTech Connect (OSTI)

An efficient method has been developed to represent the space-time behavior of neutron detector signals in nuclear reactors. The method is based on a simplified solution to the neutron shape function in the framework of a quasi-static approximation to the timedependent diffusion equation. The shape function is obtained as a sum of a modal expansion, representing the global flux perturbations, and a local function, representing the direct perturbations due to reactor parameter changes. The method was applied to the analysis of both integral and differential rod worth measurements obtained at the critical hightemperature gas-cooled reactor test facility, Kahter. The analysis of the Kahter data indicates the applicability of the proposed method in accounting for space-time effects in detector signals.

Moreia, J.; Lee, J.C.

1984-01-01T23:59:59.000Z

131

On the extension of Newton's second law to theories of gravitation in curved space-time  

E-Print Network [OSTI]

We investigate the possibility of extending Newton's second law to the general framework of theories in which special relativity is locally valid, and in which gravitation changes the flat Galilean space-time metric into a curved metric. This framework is first recalled, underlining the possibility to uniquely define a space metric and a local time in any given reference frame, hence to define velocity and momentum in terms of the local space and time standards. It is shown that a unique consistent definition can be given for the derivative of a vector (the momentum) along a trajectory. Then the possible form of the gravitation force is investigated. It is shown that, if the motion of free particles has to follow space-time geodesics, then the expression for the gravity acceleration is determined uniquely. It depends on the variation of the metric with space and time, and it involves the velocity of the particle.

Mayeul Arminjon

2006-09-14T23:59:59.000Z

132

Probing space-time structure of new physics with polarized beams at the ILC  

E-Print Network [OSTI]

At the International Linear Collider large beam polarization of both the electron and positron beams will enhance the signature of physics due to interactions that are beyond the Standard Model. Here we review our recently obtained results on a general model independent method of determining for an arbitary one-particle inclusive state the space-time structure of such new physics through the beam polarization dependence and angular distribution of the final state particle.

B. Ananthanarayan

2006-07-03T23:59:59.000Z

133

Boundary Effects on Bose-Einstein Condensation in Ultra-Static Space-Times  

E-Print Network [OSTI]

The boundary effects on the Bose-Einstein condensation of an ideal Bose gas on an ultra-static space-time are studied by a Mellin-Barnes type asymptotic analysis of the harmonic sum representing the depletion coefficient. Small $\\beta m$ regime, which is the relevant regime for the relativistic gas, is studied through the heat kernel expansion for both Dirichlet and Neumann boundary conditions. The analysis is made for both charged bosons and neutral bosons.

L. Akant; E. Ertugrul; Y. Gul; O. T. Turgut

2014-07-08T23:59:59.000Z

134

Boundary Effects on Bose-Einstein Condensation in Ultra-Static Space-Times  

E-Print Network [OSTI]

The boundary effects on the Bose-Einstein condensation of an ideal Bose gas on an ultra-static space-time are studied by a Mellin-Barnes type asymptotic analysis of the harmonic sum representing the depletion coefficient. Small $\\beta m$ regime, which is the relevant regime for the relativistic gas, is studied through the heat kernel expansion for both Dirichlet and Neumann boundary conditions. The analysis is made for both charged bosons and neutral bosons.

Akant, L; Gul, Y; Turgut, O T

2015-01-01T23:59:59.000Z

135

Stress-energy tensor in colliding plane wave space-times: An approximation procedure  

E-Print Network [OSTI]

In a recent work on the quantization of a massless scalar field in a particular colliding plane wave space-time, we computed the vacuum expectation value of the stress-energy tensor on the physical state which corresponds to the Minkowski vacuum before the collision of the waves. We did such a calculation in a region close to both the Killing-Cauchy horizon and the folding singularities that such a space-time contains. In the present paper, we give a suitable approximation procedure to compute this expectation value, in the conformal coupling case, throughout the causal past of the center of the collision. This will allow us to approximately study the evolution of such an expectation value from the beginning of the collision until the formation of the Killing-Cauchy horizon. We start with a null expectation value before the arrival of the waves, which then acquires nonzero values at the beginning of the collision and grows unbounded towards the Killing-Cauchy horizon. The value near the horizon is compatible with our previous result, which means that such an approximation may be applied to other colliding plane wave space-times. Even with this approximation, the initial modes propagated into the interaction region contain a function which cannot be calculated exactly and to ensure the correct regularization of the stress-energy tensor with the point-splitting technique, this function must be given up to adiabatic order four of approximation.

Miquel Dorca

1997-11-07T23:59:59.000Z

136

Cosmological perturbations in the (1+3+6)-dimensional space-times  

E-Print Network [OSTI]

Cosmological perturbations in the (1+3+6)-dimensional space-times including photon gas without viscous processes are studied on the basis of Abbott et al.'s formalism. Space-times consist of the outer space (the 3-dimensional expanding section) and the inner space (the 6-dimensional section). The inner space expands initially and contracts later. Abbott et al. derived only power-type solutions in the small wave-number limit which appear at the final stage of the space-times. In this paper, we derive not only small wave-number solutions, but also large wave-number solutions. It is found that the latter solutions depend on the two wave-numbers k_r and k_R (which are defined in the outer and inner spaces, respectively), and that the k_r-dependent and k_R-dependent parts dominate the total perturbations when (k_r/r(t))/(k_R/R(t)) >> 1 or spaces. By comparing the behaviors of these perturbations, moreover, changes in the spectrum of perturbations in the outer space with time are discussed.

Kenji Tomita

2014-12-20T23:59:59.000Z

137

Asymptotically Stationary and Static Space-times and Shear-free Null Geodesic Congruences  

E-Print Network [OSTI]

In classical electromagnetic theory, one formally defines the complex dipole moment (the electric plus 'i' magnetic dipole) and then computes (and defines) the complex center of charge by transforming to a complex frame where the complex dipole moment vanishes. Analogously in asymptotically flat space-times it has been shown that one can determine the complex center of mass by transforming the complex gravitational dipole (mass dipole plus 'i' angular momentum) (via an asymptotic tetrad trasnformation) to a frame where the complex dipole vanishes. We apply this procedure to such space-times which are asymptotically stationary or static, and observe that the calculations can be performed exactly, without any use of the approximation schemes which must be employed in general. In particular, we are able to exactly calculate complex center of mass and charge world-lines for such space-times, and - as a special case - when these two complex world-lines coincide, we recover the Dirac value of the gyromagnetic ratio.

T. M. Adamo; E. T. Newman

2009-06-12T23:59:59.000Z

138

General relativity as the effective theory of GL(4,R) spontaneous symmetry breaking  

SciTech Connect (OSTI)

We assume a GL(4,R) space-time symmetry which is spontaneously broken to SO(3,1). We carry out the coset construction of the effective theory for the nonlinearly realized broken symmetry in terms of the Goldstone fields and matter fields transforming linearly under the unbroken Lorentz subgroup. We then identify functions of the Goldstone and matter fields that transform linearly also under the broken symmetry. Expressed in terms of these quantities the effective theory reproduces the vierbein formalism of general relativity with general coordinate invariance being automatically realized nonlinearly over GL(4,R). The coset construction makes no assumptions about any underlying theory that might be responsible for the assumed symmetry breaking. We give a brief discussion of the possibility of field theories with GL(4,R) rather than Lorentz space-time symmetry providing the underlying dynamics.

Tomboulis, E. T. [Department of Physics and Astronomy, UCLA, Los Angeles, California 90095-1547 (United States)

2011-10-15T23:59:59.000Z

139

General Relativity as the effective theory of GL(4,R) spontaneous symmetry breaking  

E-Print Network [OSTI]

We assume a GL(4,R) space-time symmetry which is spontaneously broken to SO(3,1). We carry out the coset construction of the effective theory for the non-linearly realized broken symmetry in terms of the Goldstone fields and matter fields transforming linearly under the unbroken Lorentz subgroup. We then identify functions of the Goldstone and matter fields that transform linearly also under the broken symmetry. Expressed in terms of these quantities the effective theory reproduces the vierbein formalism of General Relativity with general coordinate invariance being automatically realized non-linearly over GL(4,R). The coset construction makes no assumptions about any underlying theory that might be responsible for the assumed symmetry breaking. We give a brief discussion of the possibility of field theories with GL(4,R) rather than Lorentz space-time symmetry providing the underlying dynamics.

E. T. Tomboulis

2011-05-30T23:59:59.000Z

140

Generalized CP symmetries and special regions of parameter space in the two-Higgs-doublet model  

SciTech Connect (OSTI)

We consider the impact of imposing generalized CP symmetries on the Higgs sector of the two-Higgs-doublet model, and identify three classes of symmetries. Two of these classes constrain the scalar potential parameters to an exceptional region of parameter space, which respects either a Z{sub 2} discrete flavor symmetry or a U(1) symmetry. We exhibit a basis-invariant quantity that distinguishes between these two possible symmetries. We also show that the consequences of imposing these two classes of CP symmetry can be achieved by combining Higgs family symmetries, and that this is not possible for the usual CP symmetry. We comment on the vacuum structure and on renormalization in the presence of these symmetries. Finally, we demonstrate that the standard CP symmetry can be used to build all the models we identify, including those based on Higgs family symmetries.

Ferreira, P. M. [Instituto Superior de Engenharia de Lisboa, Rua Conselheiro Emidio Navarro, 1900 Lisboa (Portugal); Centro de Fisica Teorica e Computacional, Faculdade de Ciencias, Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal); Haber, Howard E. [Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, California 95064 (United States); Silva, Joao P. [Instituto Superior de Engenharia de Lisboa, Rua Conselheiro Emidio Navarro, 1900 Lisboa (Portugal); Centro de Fisica Teorica de Particulas, Instituto Superior Tecnico, P-1049-001 Lisboa (Portugal)

2009-06-01T23:59:59.000Z

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


141

Quantized topological terms in weakly coupled gauge theories and their connection to symmetry protected topological phases  

E-Print Network [OSTI]

We consider a weakly coupled gauge theory where charged particles all have large gaps (ie no Higgs condensation to break the gauge "symmetry") and the field strength fluctuates only weakly. We ask what kind of topological terms can be added to the Lagrangian of such a weakly coupled gauge theory. In this paper, we systematically construct quantized topological terms which are generalization of the Chern-Simons terms and $F\\wedge F$ terms, in space-time dimensions $d$ and for any gauge groups (continuous or discrete), using each element of the topological cohomology classes $H^{d+1}(BG,\\Z)$ on the classifying space $BG$ of the gauge group $G$. In 3$d$ or for finite gauge groups above 3$d$, the weakly coupled gauge theories are gapped. So our results on topological terms can be viewed as a systematic construction of gapped topologically ordered phases of weakly coupled gauge theories. In other cases, the weakly coupled gauge theories are gapless. So our results can be viewed as an attempt to systematically cons...

Hung, Ling-Yan

2012-01-01T23:59:59.000Z

142

Energy of gravitational radiation in plane-symmetric space-times  

E-Print Network [OSTI]

Gravitational radiation in plane-symmetric space-times can be encoded in a complex potential, satisfying a non-linear wave equation. An effective energy tensor for the radiation is given, taking a scalar-field form in terms of the potential, entering the field equations in the same way as the matter energy tensor. It reduces to the Isaacson energy tensor in the linearized, high-frequency approximation. An energy conservation equation is derived for a quasi-local energy, essentially the Hawking energy. A transverse pressure exerted by interacting low-frequency gravitational radiation is predicted.

Sean A. Hayward

2008-05-19T23:59:59.000Z

143

Global structure of Robinson-Trautman radiative space-times with cosmological constant  

E-Print Network [OSTI]

Robinson-Trautman radiative space-times of Petrov type II with a non-vanishing cosmological constant Lambda and mass parameter m>0 are studied using analytical methods. They are shown to approach the corresponding spherically symmetric Schwarzschild-de Sitter or Schwarzschild-anti-de Sitter solution at large retarded times. Their global structure is analyzed, and it is demonstrated that the smoothness of the extension of the metrics across the horizon, as compared with the case Lambda=0, is increased for Lambda>0 and decreased for Lambda0 exhibit explicitly the cosmic no-hair conjecture under the presence of gravitational waves.

J. Bicak; J. Podolsky

1999-01-07T23:59:59.000Z

144

Clock rates, clock settings and the physics of the space-time Lorentz transformation  

E-Print Network [OSTI]

A careful study is made of the operational meaning of the time symbols appearing in the space-time Lorentz transformation. Four distinct symbols, with different physical meanings, are needed to describe reciprocal measurements involving stationary and uniformly-moving clocks. Physical predictions concern only the observed rate of a clock as a function of its relative speed, not its setting. How the failure to make this distinction leads to the conventional predictions of spurious `relativity of simultaneity' and `length contraction' effects in special relativity is explained.

J. H. Field

2007-12-04T23:59:59.000Z

145

Infrared problem for the Nelson model on static space-times  

E-Print Network [OSTI]

We consider the Nelson model with variable coefficients and investigate the problem of existence of a ground state and the removal of the ultraviolet cutoff. Nelson models with variable coefficients arise when one replaces in the usual Nelson model the flat Minkowski metric by a static metric, allowing also the boson mass to depend on position. A physical example is obtained by quantizing the Klein-Gordon equation on a static space-time coupled with a non-relativistic particle. We investigate the existence of a ground state of the Hamiltonian in the presence of the infrared problem, i.e. assuming that the boson mass tends to 0 at infinity.

Christian Gérard; Fumio Hiroshima; Annalisa Panati; Akito Suzuki

2011-01-03T23:59:59.000Z

146

Solution of the space-time reactor kinetics equations using the method of Laplace transforms  

E-Print Network [OSTI]

scale for the fast reactor will be a few orders of magnitude smaller than that for the thermal reactor at very early times. At later t1mes, the s, exponen- tial in equations (16) and ( 17) will dominate the solution in both reactors since... for the degree of MASTER OF SCIENCE December 1982 Major Subject: Nuclear Engineering SOLUTION OF THE SPACE-TIME REACTOR KINETICS EQUATIONS USING THE METHOD OF LAPLACE TRANSFORMS . A Thesis by JERRY STEPHEN ROTTLER Approved as to style and content by...

Rottler, Jerry Stephen

1982-01-01T23:59:59.000Z

147

Direct space-time observation of pulse tunneling in an electromagnetic band gap  

SciTech Connect (OSTI)

We present space-time-resolved measurements of electromagnetic pulses tunneling through a coaxial electromagnetic band gap structure. The results show that during the tunneling process the field distribution inside the barrier is an exponentially decaying standing wave whose amplitude increases and decreases as it slowly follows the temporal evolution of the input pulse. At no time is a pulse maximum found inside the barrier, and hence the transmitted peak is not the incident peak that has propagated to the exit. The results support the quasistatic interpretation of tunneling dynamics and confirm that the group delay is not the traversal time of the input pulse peak.

Doiron, Serge; Hache, Alain [Department de physique et d'astronomie, Universite de Moncton, Moncton, New Brunswick, E1A 3E9 (Canada); Winful, Herbert G. [Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Avenue, Ann Arbor, Michigan 48109-2122 (United States)

2007-08-15T23:59:59.000Z

148

QFT, String Temperature and the String Phase of de Sitter Space-time  

E-Print Network [OSTI]

The density of mass levels \\rho(m) and the critical temperature for strings in de Sitter space-time are found. QFT and string theory in de Sitter space are compared. A `Dual'-transform is introduced which relates classical to quantum string lengths, and more generally, QFT and string domains. Interestingly, the string temperature in De Sitter space turns out to be the Dual transform of the QFT-Hawking-Gibbons temperature. The back reaction problem for strings in de Sitter space is addressed selfconsistently in the framework of the `string analogue' model (or thermodynamical approach), which is well suited to combine QFT and string study.We find de Sitter space-time is a self-consistent solution of the semiclassical Einstein equations in this framework. Two branches for the scalar curvature R(\\pm) show up: a classical, low curvature solution (-), and a quantum high curvature solution (+), enterely sustained by the strings. There is a maximal value for the curvature R_{\\max} due to the string back reaction. Int...

Medrano, M R

1999-01-01T23:59:59.000Z

149

Geodesic motion in the space-time of cosmic strings interacting via magnetic fields  

E-Print Network [OSTI]

We study the geodesic motion of test particles in the space-time of two Abelian-Higgs strings interacting via their magnetic fields. These bound states of cosmic strings constitute a field theoretical realization of p-q-strings which are predicted by inflationary models rooted in String Theory, e.g. brane inflation. In contrast to previously studied models describing p-q-strings our model possesses a Bogomolnyi-Prasad-Sommerfield (BPS) limit. If cosmic strings exist it would be exciting to detect them by direct observation. We propose that this can be done by the observation of test particle motion in the space-time of these objects. In order to be able to make predictions we have to solve the field equations describing the configuration as well as the geodesic equation numerically. The geodesics can then be classified according to the test particle's energy, angular momentum and momentum along the string axis. We find that the interaction of two Abelian-Higgs strings can lead to the existence of bound orbits that would be absent without the interaction. We also discuss the minimal and maximal radius of orbits and comment on possible applications in the context of gravitational wave emission.

Betti Hartmann; Valeria Kagramanova

2012-07-25T23:59:59.000Z

150

Spectrum of Hydrogen Atom in Space-Time Non-Commutativity  

E-Print Network [OSTI]

We study space-time noncommutativity applied to the hydrogen atom and its phenomenological effects. We find that it modifies the potential part of the Hamiltonian in such a way we get the Kratzer potential instead of the Coulomb one and this is similar to add a dipole potential or to consider the extended charged nature of the proton in the nucleus. By calculating the energies from the Schr\\"odinger equation analytically and computing the fine structure corrections using perturbation theory, we study the modifications of the hydrogen spectrum. We find that it removes the degeneracy with respect to both the orbital quantum number l and the total angular momentum quantum number j; it acts here like a Lamb shift. Comparing the results with the experimental values from spectroscopy, we get a new bound for the space-time non-commutative parameter. We do the same perturbative calculation for the relativistic case and compute the corrections of the Dirac energies; we find that in this case too, the corrections are similar to a Lamb shift and they remove the degeneracy with respect to j ; we get an other bound for the parameter of non-commutativity.

M. Moumni; A. BenSlama; S. Zaim

2011-06-13T23:59:59.000Z

151

Fractal space-times under the microscope: A Renormalization Group view on Monte Carlo data  

E-Print Network [OSTI]

The emergence of fractal features in the microscopic structure of space-time is a common theme in many approaches to quantum gravity. In this work we carry out a detailed renormalization group study of the spectral dimension $d_s$ and walk dimension $d_w$ associated with the effective space-times of asymptotically safe Quantum Einstein Gravity (QEG). We discover three scaling regimes where these generalized dimensions are approximately constant for an extended range of length scales: a classical regime where $d_s = d, d_w = 2$, a semi-classical regime where $d_s = 2d/(2+d), d_w = 2+d$, and the UV-fixed point regime where $d_s = d/2, d_w = 4$. On the length scales covered by three-dimensional Monte Carlo simulations, the resulting spectral dimension is shown to be in very good agreement with the data. This comparison also provides a natural explanation for the apparent puzzle between the short distance behavior of the spectral dimension reported from Causal Dynamical Triangulations (CDT), Euclidean Dynamical Triangulations (EDT), and Asymptotic Safety.

Martin Reuter; Frank Saueressig

2011-10-24T23:59:59.000Z

152

Non-perfect-fluid space-times in thermodynamic equilibrium and generalized Friedmann equations  

E-Print Network [OSTI]

Assuming homogeneous and parallax-free space-times, in the case of thermodynamic equilibrium, we construct the energy-momentum tensor of non-perfect fluids. To this end we derive the constitutive equations for energy density, isotropic and anisotropic pressure as well as heat-flux from the respective propagation equations. This provides these quantities in closed form, i. e. in terms of the structure constants of the three-dimensional isometry group of homogeneity and, respectively, of the kinematical quantities expansion, rotation and acceleration. Using Einstein's equations, the thereby occurring constants of integration can be determined such that one gets bounds on the kinematical quantities and finds a generalized form of the Friedmann equations. As a consequence, it is shown that, e. g., for a perfect fluid the Friedmann and G\\"odel models can be recovered. All this is derived without assuming any equations of state or other specific thermodynamic conditions, and, in principle, allows one to go beyond the standard phase cosmology to describe the transition from phase to phase dynamically. The constitutive equations deduced for the class of space-times under consideration point in the direction of extended thermodynamics.

Konrad Schatz; Horst-Heino von Borzeszkowski; Thoralf Chrobok

2014-11-29T23:59:59.000Z

153

Space-time power schedule for distributed MIMO links without instantaneous channel state information at the transmitting nodes  

E-Print Network [OSTI]

We have proposed a space–time optimal power schedulingin [4]–[7]. In [4], a space-only (i.e. , time-invariant)are all and . Scheme A5 space-only schemes. Here, RONG et

Rong, Yue; Hua, Yingbo; Swami, Ananthram; Swindlehurst, A. Lee

2008-01-01T23:59:59.000Z

154

3526 IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, VOL. 7, NO. 9, SEPTEMBER 2008 Hierarchical Space-Time Block Code Recognition  

E-Print Network [OSTI]

at low signal-to-noise ratios. Index Terms--MIMO, space-time coding, electronic warfare. I. INTRODUCTION electronic warfare, surveillance and threat analysis. Some algorithms devoted to the blind recognition

Brest, Université de

155

Higher Dimensional Szekeres' Space-time in Brans-Dicke Scalar Tensor Theory  

E-Print Network [OSTI]

The generalized Szekeres family of solution for quasi-spherical space-time of higher dimensions are obtained in the scalar tensor theory of gravitation. Brans-Dicke field equations expressed in Dicke's revised units are exhaustively solved for all the subfamilies of the said family. A particular group of solutions may also be interpreted as due to the presence of the so-called C-field of Hoyle and Narlikar and for a chosen sign of the coupling parameter. The models show either expansion from a big bang type of singularity or a collapse with the turning point at a lower bound. There is one particular case which starts from the big bang, reaches a maximum and collapses with the in course of time to a crunch.

Asit Banerjee; Ujjal Debnath; Subenoy Chakraborty

2004-04-21T23:59:59.000Z

156

Classical stability of black hole Cauchy horizons in two-dimensional asymptotically flat space-times  

E-Print Network [OSTI]

In this paper we analyse the stability of black hole Cauchy horizons arising in a class of 2d dilaton gravity models. It is shown that due to the characteristic asymptotic Rindler form of the metric of these models, time dependent gravitational perturbations generated in the external region do not necessarily blow-up when propagated along the Cauchy horizon. There exists, in fact, a region of nonzero measure in the space of the parameters characterizing the solutions such that both instability and mass inflation are avoided. This is a new result concerning asymptotically flat space-times, not shared by the well-known solutions of General Relativity. Despite this fact, however, quantum back-reaction seems to produce a scalar curvature singularity there.

A. Fabbri

1996-07-04T23:59:59.000Z

157

Cosmological entropy production and viscous processes in the (1+3+6)-dimensional space-times  

E-Print Network [OSTI]

The cosmological entropy production is studied in the (1+3+6)-dimensional space-times consisting of the outer space (the 3-dimensional expanding section) and the inner space (the 6-dimensional section). The inner space expands initially and contracts later. First it is shown how the production of the 3-dimensional entropy S_3 within the horizon is strengthened by the dissipation due to viscous processes between the two spaces, in which we consider the viscosity caused by the gravitational-wave transport. Next it is shown under what conditions we can have the critical epoch when S_3 reaches the value 10^{88} in the Guth level and at the same time the outer space is decoupled from the inner space. Moreover, the total entropy S_9 in the 9-dimensional space at the primeval expanding stage is also shown corresponding to S_3.

Kenji Tomita

2014-05-23T23:59:59.000Z

158

Higher Rank Conformal Fields in the $Sp(2M)$ Symmetric Generalized Space-Time  

E-Print Network [OSTI]

We study various $Sp(2M)$ invariant field equations corresponding to rank $r$ tensor products of the Fock (singleton) representation of $Sp(2M)$. These equations are shown to describe localization on ``branes'' of different dimensions embedded into the generalized space-time $\\M_M$ with matrix (i.e., ``central charge'') coordinates. The case of bilinear tensor product is considered in detail. The conserved currents built from bilinears of rank 1 fields in $\\M_M$ are shown to satisfy the field equations of the rank 2 fields in $\\M_M$. Also, the rank 2 fields in $\\M_M$ are shown to be equivalent to the rank 1 fields in $\\M_{2M}$.

O. A. Gelfond; M. A. Vasiliev

2005-05-19T23:59:59.000Z

159

Origin of matter and space-time in the big bang  

SciTech Connect (OSTI)

We review the case for and against a bulk cosmic motion resulting from the quantum entanglement of our universe with the multiverse beyond our horizon. Within the current theory for the selection of the initial state of the universe from the landscape multiverse there is a generic prediction that pre-inflation quantum entanglement with other universes should give rise to a cosmic bulk flow with a correlation length of order horizon size and a velocity field relative to the expansion frame of the universe. Indeed, the parameters of this motion are are tightly constrained. A robust prediction can be deduced indicating that there should be an overall motion of of about 800 km/s relative to the background space time as defined by the cosmic microwave background (CMB). This talk will summarize the underlying theoretical motivation for this hypothesis. Of course our motion relative to the background space time (CMB dipole) has been known for decades and is generally attributed to the gravitational pull of the local super cluster. However, this cosmic peculiar velocity field has been recently deduced out to very large distances well beyond that of the local super cluster by using X-ray galaxy clusters as tracers of matter motion. This is achieved via the kinematic component of the Sunyaev-Zeldovich (KSZ) effect produced by Compton scattering of cosmic microwave background photons from the local hot intracluster gas. As such, this method measures peculiar velocity directly in the frame of the cluster. Similar attempts by our group and others have attempted to independently assess this bulk flow via Type la supernova redshifts. In this talk we will review the observation case for and against the existence of this bulk flow based upon the observations and predictions of the theory. If this interpretation is correct it has profound implications in that we may be observing for the first time both the physics that occurred before the big bang and the existence of the multiverse beyond our horizon.

Mathews, G. J. [University of Notre Dame, Center for Astrophysics/JINA, Notre Dame, IN 46556, USA and Division of Theoretical Astronomy, National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Kajino, T. [Division of Theoretical Astronomy, National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan and Department of Astronomy, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Yamazaki, D. [Division of Theoretical Astronomy, National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Kusakabe, M. [School of Liberal Arts and Science, Korea Aerospace University, Goyang 412-791, Korea and Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of); Cheoun, M.-K. [Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of)

2014-05-02T23:59:59.000Z

160

Quantum process and the foundation of relational theories of space-time  

E-Print Network [OSTI]

We present current theories about the structure of space and time, where the building blocks are some fundamental entities (yes-no experiment, quantum processes, spin net-work, preparticles) that do not presuppose the existence of space and time. The relations among these objects are the base for a pregeometry of discrete character, the continuous limit of which gives rise to the physical properties of the space and time.

M. Lorente

2003-12-30T23:59:59.000Z

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


161

Discrete Element Modeling  

SciTech Connect (OSTI)

The Distinct Element Method (also frequently referred to as the Discrete Element Method) (DEM) is a Lagrangian numerical technique where the computational domain consists of discrete solid elements which interact via compliant contacts. This can be contrasted with Finite Element Methods where the computational domain is assumed to represent a continuum (although many modern implementations of the FEM can accommodate some Distinct Element capabilities). Often the terms Discrete Element Method and Distinct Element Method are used interchangeably in the literature, although Cundall and Hart (1992) suggested that Discrete Element Methods should be a more inclusive term covering Distinct Element Methods, Displacement Discontinuity Analysis and Modal Methods. In this work, DEM specifically refers to the Distinct Element Method, where the discrete elements interact via compliant contacts, in contrast with Displacement Discontinuity Analysis where the contacts are rigid and all compliance is taken up by the adjacent intact material.

Morris, J; Johnson, S

2007-12-03T23:59:59.000Z

162

CMB B-modes, spinorial space-time and Pre-Big Bang (II)  

E-Print Network [OSTI]

The BICEP2 collaboration reported recently a B-mode polarization of the cosmic microwave background (CMB) radiation inconsistent with the null hypothesis at a significance of > 5 {\\sigma}. This result has been often interpreted as a signature of primordial gravitational waves from cosmic inflation, even if actually polarized dust emission may be at the origin of such a signal. Even assuming that part of this CMB B-mode polarization really corresponds to the early Universe dynamics, its interpretation in terms of inflation and primordial gravitational waves is not the only possible one. Alternative cosmologies such as pre-Big Bang patterns and the spinorial space-time (SST) we introduced in 1996-97 can naturally account for such CMB B-modes. In particular, the SST automatically generates a privileged space direction (PSD) whose existence may have been confirmed by Planck data. If such a PSD exists, it seems normal to infer that vector perturbations have been present in the early Universe leading to CMB B-modes in suitable cosmological patterns. Inflation would not be required to explain the BICEP2 result assuming it really contains a primordial signal. More generally, pre-Big Bang cosmologies can also generate gravitational waves in the early Universe without any need for cosmic inflation. We further discuss here possible alternatives to the inflationary interpretation of a primordial B-mode polarization of cosmic microwave background radiation.

Luis Gonzalez-Mestres

2014-08-02T23:59:59.000Z

163

Space-like Dp branes: accelerating cosmologies versus conformally de Sitter space-time  

E-Print Network [OSTI]

We consider the space-like D$p$ brane solutions of type II string theories having isometries ISO$(p+1)$ $\\times$ SO$(8-p,1)$. These are asymptotically flat solutions or in other words, the metrics become flat at the time scale $\\tau \\gg \\tau_0$. On the other hand, when $\\tau \\sim \\tau_0$, we get $(p+1)+1$ dimensional flat FLRWmetrics upon compactification on a $(8-p)$ dimensional hyperbolic space with time dependent radii. We show that the resultant $(p+1)+1$ dimensional metrics describe transient accelerating cosmologies for all $p$ from 1 to 6, i.e., from $(2+1)$ to $(7+1)$ space-time dimensions. We show how the acceleration changes with the interplay of the various parameters characterizing the solutions in $(3+1)$ dimensions. Finally, for $\\tau \\ll \\tau_0$, after compactification on $(8-p)$ dimensional hyperbolic space, the resultant metrics are shown to take the form of $(p+1)+1$ dimensional de Sitter spaces upto a conformal transformation. Cosmologies here are decelerating, but, only in a particular conformal frame we get eternal acceleration.

Kuntal Nayek; Shibaji Roy

2014-11-10T23:59:59.000Z

164

Accelerating dark energy models in bianchi Type-V space-time  

E-Print Network [OSTI]

Some new exact solutions of Einstein's field equations in a spatially homogeneous and anisotropic Bianchi type-V space-time with minimally interaction of perfect fluid and dark energy components have been obtained. To prevail the deterministic solution we choose the scale factor $a(t) = \\sqrt{t^{n}e^{t}}$, which yields a time dependent deceleration parameter (DP), representing a model which generates a transition of the universe from the early decelerating phase to the recent accelerating phase. We find that for $n \\geq 1$, the quintessence model is reproducible with present and expected future evolution of the universe. The other models (for $n models approach to isotropy at late time. For different values of $n$, we can generate a class of physically viable DE models. The cosmic jerk parameter in our descended model is also found to be in good concordance with the recent data of astrophysical observations under appropriate condition. The physical and geometric properties of spatially homogeneous and anisotropic cosmological models are discussed.

Anirudh Pradhan; H. Amirhashchi

2011-10-05T23:59:59.000Z

165

Symmetries in physics  

E-Print Network [OSTI]

The concept of symmetries in physics is briefly reviewed. In the first part of these lecture notes, some of the basic mathematical tools needed for the understanding of symmetries in nature are presented, namely group theory, Lie groups and Lie algebras, and Noether's theorem. In the second part, some applications of symmetries in physics are discussed, ranging from isospin and flavor symmetry to more recent developments involving the interacting boson model and its extension to supersymmetries in nuclear physics.

Roelof Bijker

2005-09-02T23:59:59.000Z

166

$K_S$ semileptonic decays and test of $\\mathcal{CPT}$ symmetry with the KLOE detector  

E-Print Network [OSTI]

Study of semileptonic decays of neutral kaons allows to perform a test of discrete symmetries, as well as basic principles of the Standard Model. In this paper a general review on dependency between charge asymmetry constructed for semileptonic decays of short- and long-lived kaons and $\\mathcal{CPT}$ symmetry is given.

Kami?ska, D

2015-01-01T23:59:59.000Z

167

$K_S$ semileptonic decays and test of $\\mathcal{CPT}$ symmetry with the KLOE detector  

E-Print Network [OSTI]

Study of semileptonic decays of neutral kaons allows to perform a test of discrete symmetries, as well as basic principles of the Standard Model. In this paper a general review on dependency between charge asymmetry constructed for semileptonic decays of short- and long-lived kaons and $\\mathcal{CPT}$ symmetry is given.

D. Kami?ska

2015-01-19T23:59:59.000Z

168

Visibility in Discrete Geometry: an application to discrete geodesic paths  

E-Print Network [OSTI]

Visibility in Discrete Geometry: an application to discrete geodesic paths David Coeurjolly that are visible from a source pixel. Based on these definitions, we define discrete geodesic paths in dis- crete domain with obstacles. This allows us to introduce a new geodesic metric in discrete geometry

Paris-Sud XI, Université de

169

From Dirac theories in curved space-times to a Variation of Dirac's large-number hypothesis  

E-Print Network [OSTI]

An overview is given of recent developments in the field of Dirac equations generalized to curved space-times. An illustrative discussion is provided. We conclude with a variation of Dirac's large-number hypothesis which relates a number of physical quantities on cosmological scales.

U. D. Jentschura

2014-05-07T23:59:59.000Z

170

A Generic Space-Time-Frequency Correlation Model and Its Corresponding Simulation Model for Narrowband MIMO Channels  

E-Print Network [OSTI]

A Generic Space-Time-Frequency Correlation Model and Its Corresponding Simulation Model.Laurenson d9ed. ac. uk Keyword: Wireless channels, NIIMO, STF correlation, deterministic simulation model theoretical reference model, a deterministic simulation model is then proposed and its 3-D STF correlation

Wang, Cheng-Xiang

171

Modified Brans-Dicke theory with space-time anisotropic parameters  

E-Print Network [OSTI]

We consider the ADM formalism of the Brans-Dicke theory and propose an anisotropic extension of the theory by introducing five free parameters. We find that the resulting theory reveals many interesting aspects which are not present in the original BD theory. We first discuss the ghost instability and strong coupling problems which are present in the gravity theory without the full diffeomorphism symmetry and show that they can be avoided in a region of the parameter space. We also perform the post-Newtonian approximation and show that the constraint of the Brans-Dicke parameter $\\omega_{{\\rm BD}}$ being large to be consistent with the solar system observations could be evaded in the extended theory. We also discuss that accelerating Universe can be achieved without the need of the potential for the Brans-Dicke scalar.

Taeyoon Moon; Phillial Oh

2014-02-22T23:59:59.000Z

172

Universal adiabatic quantum computation via the space-time circuit-to-Hamiltonian construction  

E-Print Network [OSTI]

We show how to perform universal adiabatic quantum computation using a Hamiltonian which describes a set of particles with local interactions on a two-dimensional grid. A single parameter in the Hamiltonian is adiabatically changed as a function of time to simulate the quantum circuit. We bound the eigenvalue gap above the unique groundstate by mapping our model onto the ferromagnetic XXZ chain with kink boundary conditions; the gap of this spin chain was computed exactly by Koma and Nachtergaele using its $q$-deformed version of SU(2) symmetry. We also discuss a related time-independent Hamiltonian which was shown by Janzing to be capable of universal computation. We observe that in the limit of large system size, the time evolution is equivalent to the exactly solvable quantum walk on Young's lattice.

David Gosset; Barbara M. Terhal; Anna Vershynina

2014-09-27T23:59:59.000Z

173

A discrete fractional random transform  

E-Print Network [OSTI]

We propose a discrete fractional random transform based on a generalization of the discrete fractional Fourier transform with an intrinsic randomness. Such discrete fractional random transform inheres excellent mathematical properties of the fractional Fourier transform along with some fantastic features of its own. As a primary application, the discrete fractional random transform has been used for image encryption and decryption.

Zhengjun Liu; Haifa Zhao; Shutian Liu

2006-05-20T23:59:59.000Z

174

Topological classification of crystalline insulators with space group symmetry  

SciTech Connect (OSTI)

We show that in crystalline insulators, space group symmetry alone gives rise to a topological classification based on the discretization of electric polarization. Using C3 rotational symmetry as an example, we first prove that the polarization is discretized into three distinct classes, i.e., it can only take three inequivalent values. We then prove that these classes are topologically distinct. Therefore, a Z3 topological classification exists, with polarization as a topological class index. A concrete tight-binding model is derived to demonstrate the Z3 topological phase transition. Using first-principles calculations, we identify graphene on a BN substrate as a possible candidate to realize these Z3 topological states. To complete our analysis, we extend the classification of band structures to all 17 two-dimensional space groups. This work will contribute to a complete theory of symmetry-conserved topological phases and also elucidate topological properties of graphenelike systems.

Jadaun, Priyamvada [University of Texas at Austin; Xiao, Di [Carnegie Mellon University (CMU); Niu, Q. [University of Texas at Austin; Banerjee, Sanjay K. [University of Texas at Austin

2013-01-01T23:59:59.000Z

175

Discrete KP equation with self-consistent sources  

E-Print Network [OSTI]

We show that the discrete Kadomtsev-Petviashvili (KP) equation with sources obtained recently by the "source generalization" method can be incorporated into the squared eigenfunction symmetry extension procedure. Moreover, using the known correspondence between Darboux-type transformations and additional independent variables, we demonstrate that the equation with sources can be derived from Hirota's discrete KP equations but in a space of higher dimension. In this way we uncover the origin of the source terms as coming from multidimensional consistency of the Hirota system itself.

Adam Doliwa; Runliang Lin

2014-04-05T23:59:59.000Z

176

The Symmetries of QCD  

ScienceCinema (OSTI)

The symmetries of a quantum field theory can be realized in a variety of ways. Symmetries can be realized explicitly, approximately, through spontaneous symmetry breaking or, via an anomaly, quantum effects can dynamically eliminate a symmetry of the theory that was present at the classical level.  Quantum Chromodynamics (QCD), the modern theory of the strong interactions, exemplify each of these possibilities. The interplay of these effects determine the spectrum of particles that we observe and, ultimately, account for 99% of the mass of ordinary matter. 

Sekhar Chivukula

2010-01-08T23:59:59.000Z

177

Symmetry in Scheduling Problems  

E-Print Network [OSTI]

Nov 16, 2010 ... Using operating room and power generator scheduling problems ... Symmetry has been an obstacle in mixed integer linear programming ...

2010-11-16T23:59:59.000Z

178

Twisted symmetries and integrable systems  

E-Print Network [OSTI]

Symmetry properties are at the basis of integrability. In recent years, it appeared that so called "twisted symmetries" are as effective as standard symmetries in many respects (integrating ODEs, finding special solutions to PDEs). Here we discuss how twisted symmetries can be used to detect integrability of Lagrangian systems which are not integrable via standard symmetries.

G. Cicogna; G. Gaeta

2010-02-07T23:59:59.000Z

179

Emergence of symmetries  

E-Print Network [OSTI]

The mechanism of symmetry formation is discussed in the framework of multidimensional gravity. It is shown that this process is strictly connected to the entropy decrease of compact space. The existence of low energy symmetries is not postulated from the beginning. They could be absent during the inflationary stage under certain conditions discussed in the paper.

A. A. Kirillov; A. A. Korotkevich; S. G. Rubin

2012-10-16T23:59:59.000Z

180

Space-time properties of Gram-Schmidt vectors in classical Hamiltonian evolution Jason R. Green,1,2,3,* Julius Jellinek,2,  

E-Print Network [OSTI]

Space-time properties of Gram-Schmidt vectors in classical Hamiltonian evolution Jason R. Green,1 tangent space directions play equivalent roles in the local chaotic motions of classical Hamiltonian many vectors, whose statistical properties may depend on the chosen phase space-time domain of a trajec- tory

Berry, R. Stephen

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


181

BLIND SYMBOL IDENTIFIABILITY OF ORTHOGONAL SPACE-TIME BLOCK CODES Wing-Kin Ma , P.C. Ching , T. N. Davidson, and B.-N. Vo  

E-Print Network [OSTI]

BLIND SYMBOL IDENTIFIABILITY OF ORTHOGONAL SPACE-TIME BLOCK CODES Wing-Kin Ma , P.C. Ching , T. N Hamilton, Ont., Canada Parksville, Vic., Australia ABSTRACT This paper addresses the blind symbol. In many space-time communication schemes, achieving unique blind symbol identification requires certain

Davidson, Tim

182

Discrete and continuous exponential transforms of simple Lie groups of rank two  

E-Print Network [OSTI]

We develop and describe continuous and discrete transforms of class functions on compact simple Lie group $G$ as their expansions into series of uncommon special functions, called here $\\E$-functions in recognition of the fact that the functions generalize common exponential functions. The rank of $G$ is the number of variables in the $\\E$-functions. A uniform discretization of the decomposition problem is described on lattices of any density and symmetry admissible for the Lie group $G$.

Iryna Kashuba; Jiri Patera

2007-02-05T23:59:59.000Z

183

Neutrino masses and mixing: a flavour symmetry roadmap  

E-Print Network [OSTI]

Over the last ten years tri-bimaximal mixing has played an important role in modeling the flavour problem. We give a short review of the status of flavour symmetry models of neutrino mixing. We concentrate on non-Abelian discrete symmetries, which provide a simple way to account for the TBM pattern. We discuss phenomenological implications such as neutrinoless double beta decay, lepton flavour violation as well as theoretical aspects such as the possibility to explain quarks and leptons within a common framework, such as grand unified models.

Morisi, S

2012-01-01T23:59:59.000Z

184

Neutrino masses and mixing: a flavour symmetry roadmap  

E-Print Network [OSTI]

Over the last ten years tri-bimaximal mixing has played an important role in modeling the flavour problem. We give a short review of the status of flavour symmetry models of neutrino mixing. We concentrate on non-Abelian discrete symmetries, which provide a simple way to account for the TBM pattern. We discuss phenomenological implications such as neutrinoless double beta decay, lepton flavour violation as well as theoretical aspects such as the possibility to explain quarks and leptons within a common framework, such as grand unified models.

S. Morisi; J. W. F. Valle

2012-06-28T23:59:59.000Z

185

Solution to the transverse-phase-space time-dependence problem with LAMPF's high-intensity H/sup +/ beam  

SciTech Connect (OSTI)

The 750 keV H/sup +/ beam at LAMPF has a transverse phase-space time-dependent transient during the first 200 ..mu..s of each 750-..mu..s-long macro-pulse. The time dependence is documented in an earlier report. Further studies indicate that the time dependence is due to space-charge neutralization resulting from secondary emission of electrons produced by collisions of the H/sup +/ and H/sub 2//sup +/ beams on the transport walls. One of several possible solutions has been tested and has proven successful in eliminating the time dependence of the beam entering the linac.

Hurd, J.W.

1983-01-01T23:59:59.000Z

186

Primary and reciprocal space-time experiments, relativistic reciprocity relations and Einstein's train-embankment thought experiment  

E-Print Network [OSTI]

The concepts of primary and reciprocal experiments and base and travelling frames in special relativity are concisely described and applied to several different space-time experiments. These include Einstein's train/embankment thought experiment and a related thought experiment, due to Sartori, involving two trains in parallel motion with different speeds. Spatially separated clocks which are synchronised in their common proper frame are shown to be so in all inertial frames and their spatial separation to be Lorentz invariant. The interpretions given by Einstein and Sartori of their experiments, as well as those given by the present author in previous papers, are shown to be erroneous.

J. H. Field

2011-11-11T23:59:59.000Z

187

Finite group symmetry breaking  

E-Print Network [OSTI]

Finite group symmetry is commonplace in Physics, in particular through crystallographic groups occurring in condensed matter physics -- but also through the inversions (C,P,T and their combinations) occurring in high energy physics and field theory. The breaking of finite groups symmetry has thus been thoroughly studied, and general approaches exist to investigate it. In Landau theory, the state of a system is described by a finite dimensional variable (the {\\it order parameter}), and physical states correspond to minima of a potential, invariant under a group. In this article we describe the basics of symmetry breaking analysis for systems described by a symmetric polynomial; in particular we discuss generic symmetry breakings, i.e. those determined by the symmetry properties themselves and independent on the details of the polynomial describing a concrete system. We also discuss how the plethora of invariant polynomials can be to some extent reduced by means of changes of coordinates, i.e. how one can reduce to consider certain types of polynomials with no loss of generality. Finally, we will give some indications on extension of this theory, i.e. on how one deals with symmetry breakings for more general groups and/or more general physical systems.

G. Gaeta

2005-10-02T23:59:59.000Z

188

Semi-classical determination of exponentially small intermode transitions for 1+1 space-time scattering systems  

E-Print Network [OSTI]

We consider the semiclassical limit of systems of autonomous PDE's in 1+1 space-time dimensions in a scattering regime. We assume the matrix valued coefficients are analytic in the space variable and we further suppose that the corresponding dispersion relation admits real-valued modes only with one-dimensional polarization subspaces. Hence a BKW-type analysis of the solutions is possible. We typically consider time-dependent solutions to the PDE which are carried asymptotically in the past and as $x\\to -\\infty$ along one mode only and determine the piece of the solution that is carried for $x\\to +\\infty$ along some other mode in the future. Because of the assumed non-degeneracy of the modes, such transitions between modes are exponentially small in the semiclassical parameter; this is an expression of the Landau-Zener mechanism. We completely elucidate the space-time properties of the leading term of this exponentially small wave, when the semiclassical parameter is small, for large values of $x$ and $t$, when some avoided crossing of finite width takes place between the involved modes.

Magali Marx; Alain Joye

2005-08-24T23:59:59.000Z

189

Variable Cosmological Parameter and S-channel Quantum Matter Fields Hadamard renormalization in Spherically Symmetric Curved Space Times  

E-Print Network [OSTI]

Aim of the paper is to obtain 2d analogue of the backreaction equation which will be useful to study final state of quantum perturbed spherically symmetric curved space times. Thus we take Einstein-massless-scalar $\\psi$ tensor gravity model described on class of spherically symmetric curved space times. We rewrite the action functional in 2d analogue in terms of dimensionless dilaton-matter field $(\\chi=\\Phi\\psi)$ where dilaton field $\\Phi$ is conformal factor of 2-sphere. Then we seek renormalized expectation value of quantum dilaton-matter field stress tensor operator by applying Hadamard rennormalization prescription. Singularity of the Green function is assumed to be has logarithmic form. Covariantly conservation condition on the renormalized quantum dilaton-matter stress tensor demands to input a variable cosmological parameter $\\lambda(x)$. Energy conditions (weak, strong and null) is studied on the obtained renormalized stress tensor leading to dynamical equations for $\\lambda(x), \\Phi$ and quantum vacuum state $W_0(x)=_{ren}.$ In weak quantum field limits our obtained trace anomaly corresponds to one which obtained from zeta regularization. Setting null-like apparent horizon equation $\

Hossein Ghaffarnejad

2015-03-10T23:59:59.000Z

190

Gauge symmetry breaking in orbifold model building  

E-Print Network [OSTI]

We review the gauge symmetry breaking mechanism due to orbifold projections in orbifold model building. We explicitly show the existence of a scale of breaking if such a symmetry breaking is due to freely-acting orbifold operators only, i.e. in case the breaking is realized non-locally in the internal space. We show that such a scale is related to the compactification moduli only, and that there are no extra continuous parameters, at least in semirealistic models with N=1 SUSY in four dimensions. In this sense, the mechanism is peculiarly different from the standard Higgs (or Hosotani) symmetry breaking mechanism. We show that the mechanism also differs from that present in standard orbifold models where, even in presence of discrete Wilson lines, a scale of breaking is generically missing, since the breaking is localized in specific points in the internal space. We review a set of background geometries where the described non-local breaking is realized, both in the case of two and six extra dimensions. In the latter case, relevant in string model building, we consider both heterotic and open string compactifications.

Michele Trapletti

2006-11-02T23:59:59.000Z

191

2D and 3D Visibility in Discrete Geometry: an application to discrete geodesic paths  

E-Print Network [OSTI]

1 2D and 3D Visibility in Discrete Geometry: an application to discrete geodesic paths D discrete geodesic paths in discrete domain with obstacles. This allows us to introduce a new geodesic metric in discrete geometry. Keywords: discrete visibility, geodesic path, distance transform, discrete

Boyer, Edmond

192

Bohmian Mechanics with Discrete Operators  

E-Print Network [OSTI]

A deterministic Bohmian mechanics for operators with continuous and discrete spectra is presented. Randomness enters only through initial conditions. Operators with discrete spectra are incorporated into Bohmian mechanics by associating with each operator a continuous variable in which a finite range of the continuous variable correspond to the same discrete eigenvalue. In this way Bohmian mechanics can handle the creation and annihilation of particles. Examples are given and generalizations are discussed.

R. A. Hyman; Shane A. Caldwell; Edward Dalton

2004-01-02T23:59:59.000Z

193

Pooling problems: relaxations and discretizations  

E-Print Network [OSTI]

In section 4, we consider a general BLP and discretize one variable in every ...... 1603. 2074. 517372. 50020. 2. 4600. 4099. 1. 329. 349. 48329. 37152. 28673.

2013-09-02T23:59:59.000Z

194

Thermodynamics of discrete quantum processes  

E-Print Network [OSTI]

We define thermodynamic configurations and identify two primitives of discrete quantum processes between configurations for which heat and work can be defined in a natural way. This allows us to uncover a general second law for any discrete trajectory that consists of a sequence of these primitives, linking both equilibrium and non-equilibrium configurations. Moreover, in the limit of a discrete trajectory that passes through an infinite number of configurations, i.e. in the reversible limit, we recover the saturation of the second law. Finally, we show that for a discrete Carnot cycle operating between four configurations one recovers Carnot's thermal efficiency.

Janet Anders; Vittorio Giovannetti

2012-11-01T23:59:59.000Z

195

The algebra of discrete torsion  

E-Print Network [OSTI]

Oct 1, 2004 ... ... of Vafa's and Douglas's picture of discrete torsion, J. High Energy ... Quasi Hopf algebras, group cohomology and orbifold models, Nuclear.

2004-10-13T23:59:59.000Z

196

Dark Energy Model in Anisotropic Bianchi Type-III Space-Time with Variable EoS Parameter  

E-Print Network [OSTI]

A new dark energy model in anisotropic Bianchi type-III space-time with variable equation of state (EoS) parameter has been investigated in the present paper. To get the deterministic model, we consider that the expansion $\\theta$ in the model is proportional to the eigen value $\\sigma^{2}_{~2}$ of the shear tensor $\\sigma^{j}_~i$. The EoS parameter $\\omega$ is found to be time dependent and its existing range for this model is in good agreement with the recent observations of SNe Ia data (Knop et al. 2003) and SNe Ia data with CMBR anisotropy and galaxy clustering statistics (Tegmark et al. 2004). It has been suggested that the dark energy that explains the observed accelerating expansion of the universe may arise due to the contribution to the vacuum energy of the EoS in a time dependent background. Some physical aspects of dark energy model are also discussed.

Anirudh Pradhan; Hassan Amirhashchi

2010-10-12T23:59:59.000Z

197

Lamb shift and fundamental length of the relativistic Hydrogen atom induced from the non-commutative space-time  

E-Print Network [OSTI]

We present an important contribution to the non-commutative approach to the hydrogen atom to deal with lamb shift corrections. This can be done by studying the Klein-Gordon and Dirac equations in a non-commutative space-time up to first-order of the non-commutativity parameter using the Seiberg-Witten maps. We thus find the non-commutative modification of the energy levels and by comparing with the the current experimental results on the Lamb shift of the 2P level to extract a bound on the parameter of non-commutativity, we show that the fundamental length ($\\sqrt{\\Theta}$) is compatible with the value of the electroweak length scale ($l$). Phenomenologically, this effectively confirms the presence of gravity at this level.

Slimane Zaim

2014-04-08T23:59:59.000Z

198

Charge splitting of directed flow and space-time picture of pion emission from the electromagnetic interactions with spectators  

E-Print Network [OSTI]

We estimate the effect of the spectator-induced electromagnetic interaction on the directed flow of charged pions. For intermediate centrality Au+Au collisions at $\\sqrt{s_{NN}}=7.7$~GeV, we demonstrate that the electromagnetic interaction between spectator charges and final state pions results in charge splitting of positive and negative pion directed flow. Such a charge splitting is visible in the experimental data reported by the STAR Collaboration. The magnitude of this charge splitting appears to strongly depend on the actual distance between the pion emission site (pion at freeze-out) and the spectator system. As such, the above electromagnetic effect brings new, independent information on the space-time evolution of pion production in heavy ion collisions. From the comparison of our present analysis to our earlier studies made for pions produced at higher rapidity, we formulate conclusions on the rapidity dependence of the distance between the pion emission site and the spectator system. This distance appears to decrease with increasing pion rapidity, reflecting the longitudinal expansion of the strongly-interacting system responsible for pion emission. Thus for the first time, information on the space-time characteristics of the system is being provided by means of the spectator-induced electromagnetic interaction. The above electromagnetic effect being in fact a straight-forward consequence of the presence of spectator charges in the collision, we consider that it should be considered as a baseline for studies of other phenomena, like those related to the electric conductivity of the quark-gluon plasma.

Andrzej Rybicki; Antoni Szczurek

2014-05-27T23:59:59.000Z

199

Symmetry planes of Paleozoic crinoids  

E-Print Network [OSTI]

Webster—Symmetry Planes of Paleozoic Crinoids 15Lane and -vestibule o CD 1 6 moot: 5 -hydropore 8b 7b Fin. 1—Symmetry planes of Paleozoic crinoids (1-5) and crinoid larvae (6-10). I. Anteroposterior (A-CD) symmetry plane of most Paleozoic crinoids... Webster—Symmetry Planes of Paleozoic Crinoids 15Lane and -vestibule o CD 1 6 moot: 5 -hydropore 8b 7b Fin. 1—Symmetry planes of Paleozoic crinoids (1-5) and crinoid larvae (6-10). I. Anteroposterior (A-CD) symmetry plane of most Paleozoic crinoids...

Lane, N. G.; Webster, G. D.

1967-11-30T23:59:59.000Z

200

Beyond Space-Time  

E-Print Network [OSTI]

These notes, based on the remarks made at the 23 Solvay Conference, collect several speculative ideas concerning gauge/ strings duality, de Sitter spaces, dimensionality and the cosmological constant.

A. M. Polyakov

2006-02-01T23:59:59.000Z

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


201

Two-dimensional symmetry-protected topological orders and their protected gapless edge excitations  

SciTech Connect (OSTI)

Topological insulators in free fermion systems have been well characterized and classified. However, it is not clear in strongly interacting boson or fermion systems what symmetry-protected topological orders exist. In this paper, we present a model in a two-dimensional (2D) interacting spin system with nontrivial onsite Z{sub 2} symmetry-protected topological order. The order is nontrivial because we can prove that the one-dimensional (1D) system on the boundary must be gapless if the symmetry is not broken, which generalizes the gaplessness of Wess-Zumino-Witten model for Lie symmetry groups to any discrete symmetry groups. The construction of this model is related to a nontrivial 3-cocycle of the Z{sub 2} group and can be generalized to any symmetry group. It potentially leads to a complete classification of symmetry-protected topological orders in interacting boson and fermion systems of any dimension. Specifically, this exactly solvable model has a unique gapped ground state on any closed manifold and gapless excitations on the boundary if Z{sub 2} symmetry is not broken. We prove the latter by developing the tool of a matrix product unitary operator to study the nonlocal symmetry transformation on the boundary and reveal the nontrivial 3-cocycle structure of this transformation. Similar ideas are used to construct a 2D fermionic model with onsite Z{sub 2} symmetry-protected topological order.

Chen Xie [Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Liu Zhengxin; Wen Xiaogang [Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Institute for Advanced Study, Tsinghua University, Beijing, 100084 (China)

2011-12-15T23:59:59.000Z

202

Mirror Symmetry Constructions  

E-Print Network [OSTI]

These expository notes are based on lectures by Yongbin Ruan during a special semester on the B-model at the University of Michigan in Winter 2014. They outline and compare the mirror symmetry constructions of Batyrev-Borisov, Hori-Vafa, and Bergland-Hubsch-Krawitz.

Emily Clader; Yongbin Ruan

2014-12-03T23:59:59.000Z

203

Observable T{sub 7} Lepton Flavor Symmetry at the Large Hadron Collider  

SciTech Connect (OSTI)

More often than not, models of flavor symmetry rely on the use of nonrenormalizable operators (in the guise of flavons) to accomplish the phenomenologically successful tribimaximal mixing of neutrinos. We show instead how a simple renormalizable two-parameter neutrino mass model of tribimaximal mixing can be constructed with the non-Abelian discrete symmetry T{sub 7} and the gauging of B-L. This is also achieved without the addition of auxiliary symmetries and particles present in almost all other proposals. Most importantly, it is verifiable at the Large Hadron Collider.

Cao Qinghong [High Energy Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637 (United States); Khalil, Shaaban [Centre for Theoretical Physics, British University in Egypt, El Sherouk City, Postal No. 11837, P.O. Box 43 (Egypt); Department of Mathematics, Ain Shams University, Faculty of Science, Cairo 11566 (Egypt); Ma, Ernest [Department of Physics and Astronomy, University of California, Riverside, California 92521 (United States); Okada, Hiroshi [Centre for Theoretical Physics, British University in Egypt, El Sherouk City, Postal No. 11837, P.O. Box 43 (Egypt)

2011-04-01T23:59:59.000Z

204

Symmetry Energy in Nuclear Surface  

E-Print Network [OSTI]

Interplay between the dependence of symmetry energy on density and the variation of nucleonic densities across nuclear surface is discussed. That interplay gives rise to the mass dependence of the symmetry coefficient in an energy formula. Charge symmetry of the nuclear interactions allows to introduce isoscalar and isovector densities that are approximately independent of the magnitude of neutron-proton asymmetry.

Pawel Danielewicz; Jenny Lee

2008-12-25T23:59:59.000Z

205

Symmetry Energy in Nuclear Surface  

E-Print Network [OSTI]

Interplay between the dependence of symmetry energy on density and the variation of nucleonic densities across nuclear surface is discussed. The interplay leads to a dependence of the symmetry coefficient, in energy formula, on nuclear mass. Charge symmetry of nuclear interactions allows to introduce isoscalar and isovector densities that are approximately independent of neutron-proton asymmetry.

Danielewicz, Pawel

2008-01-01T23:59:59.000Z

206

Discrete generalized multigroup theory and applications  

E-Print Network [OSTI]

This study develops a fundamentally new discrete generalized multigroup energy expansion theory for the linear Boltzmann transport equation. Discrete orthogonal polynomials are used, in conjunction with the traditional ...

Zhu, Lei, Ph. D. Massachusetts Institute of Technology

2012-01-01T23:59:59.000Z

207

Gravitation and Duality Symmetry  

E-Print Network [OSTI]

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 is not dual symmetric, there is a particular theory in which this symmetry shows up. It is a self dual (or anti-self dual) teleparallel gravity in which, due to the fact that it does not contribute to the interaction of fermions with gravitation, the purely tensor part of torsion is assumed to vanish. The ensuing fermionic gravitational interaction is found to be chiral. Since duality is intimately related to renormalizability, this theory may eventually be more amenable to renormalization than teleparallel gravity or general relativity.

V. C. de Andrade; A. L. Barbosa; J. G. Pereira

2005-05-16T23:59:59.000Z

208

Modern theories of discrete time  

E-Print Network [OSTI]

We review some modern theories about the structure of space and time, in particular those related to discrete space and time. Following an epistemological method we start from theories which discuss discrete space and time as a mathematical tool to solve physical models. Antother theories look for physical content of the discrete structure of space and time, based in relational theories of space and time which are derived from the relations of some fundamental entities. Finally we present some philosophical positions who try to find the ontological foundation of the relational theories os space and time.

M. Lorente

2003-12-31T23:59:59.000Z

209

Stability of Gauss-Bonnet black holes in anti-de Sitter space-time against scalar field condensation  

SciTech Connect (OSTI)

We study the stability of static, hyperbolic Gauss-Bonnet black holes in (4+1)-dimensional anti-de Sitter (AdS) space-time against the formation of scalar hair. Close to extremality the black holes possess a near-horizon topology of AdS{sub 2}xH{sup 3} such that within a certain range of the scalar field mass one would expect that they become unstable to the condensation of an uncharged scalar field. We confirm this numerically and observe that there exists a family of hairy black hole solutions labeled by the number of nodes of the scalar field function. We construct explicit examples of solutions with a scalar field that possesses zero nodes, one node, and two nodes, respectively, and show that the solutions with nodes persist in the limit of Einstein gravity, i.e. for vanishing Gauss-Bonnet coupling. We observe that the interval of the mass for which scalar field condensation appears decreases with increasing Gauss-Bonnet coupling and/or with increasing node number.

Brihaye, Yves [Physique-Mathematique, Universite de Mons-Hainaut, 7000 Mons (Belgium); Hartmann, Betti [School of Engineering and Science, Jacobs University Bremen, 28759 Bremen (Germany)

2011-10-15T23:59:59.000Z

210

Symmetries in open quantum dynamics  

E-Print Network [OSTI]

Simple examples are used to introduce and examine a Heisenberg picture of symmetries of open quantum dynamics that can be described by unitary operators. When the symmetries are for Hamiltonian dynamics of an entire system, and the spectrum of the Hamiltonian operator has a lower bound, the symmetry operators commute with the Hamiltonian operator. An example shows that symmetry operators need not commute with the Hamiltonian operator when the spectrum of the Hamiltonian does not have a lower bound. There are many more symmetries that are only for the open dynamics of a subsystem and are described by unitary operators that do not commute with the Hamiltonian for the dynamics of the entire system. Examples show how these symmetries alone can reveal properties of the dynamics and reduce what needs to be done to work out the dynamics. A symmetry of the open dynamics of a subsystem can imply properties of the dynamics for the entire system that are not implied by the symmetries of the dynamics of the entire system. The symmetries are generally not related to constants of the motion for the open dynamics of the subsystem. There are symmetries of the open dynamics of a subsystem that depend only on the dynamics. In the simplest examples, these are also symmetries of the dynamics of the entire system. There are many more symmetries, of a new kind, that also depend on correlations, or absence of correlations, between the subsystem and the rest of the entire system, or on the state of the rest of the entire system. Symmetries that depend on correlations generally cannot be seen in the Schr\\"{o}dinger picture as symmetries of dynamical maps of density matrices for the subsystem.

Thomas F. Jordan

2014-08-20T23:59:59.000Z

211

Discrete Structures for Computer Science  

E-Print Network [OSTI]

-5% Final Exam 40% #12;Why Discrete Math? Design efficient computer systems. ·How did Google manage to build issues. #12;16 Sub-Category Graph No Threshold New Science of Networks NYS Electric Power Grid (Thorp

Dragan, Feodor F.

212

On discretizations of axisymmetric systems  

E-Print Network [OSTI]

In this paper we discuss stability properties of various discretizations for axisymmetric systems including the so called cartoon method which was proposed by Alcubierre, Brandt et.al. for the simulation of such systems on Cartesian grids. We show that within the context of the method of lines such discretizations tend to be unstable unless one takes care in the way individual singular terms are treated. Examples are given for the linear axisymmetric wave equation in flat space.

J. Frauendiener

2002-07-24T23:59:59.000Z

213

Hidden symmetries and killing tensors on curved spaces  

SciTech Connect (OSTI)

Higher-order symmetries corresponding to Killing tensors are investigated. The intimate relation between Killing-Yano tensors and nonstandard supersymmetries is pointed out. In the Dirac theory on curved spaces, Killing-Yano tensors generate Dirac-type operators involved in interesting algebraic structures as dynamical algebras or even infinite dimensional algebras or superalgebras. The general results are applied to space-times which appear in modern studies. One presents the infinite dimensional superalgebra of Dirac type operators on the 4-dimensional Euclidean Taub-NUT space that can be seen as a twisted loop algebra. The existence of the conformal Killing-Yano tensors is investigated for some spaces with mixed 3-Sasakian structures.

Ianus, S. [University of Bucharest, Department of Mathematics (Romania); Visinescu, M., E-mail: mvisin@theory.nipne.r [Institute for Physics and Nuclear Engineering, Department of Theoretical Physics (Romania); Vilcu, G. E. [Petroleum-Gas University of Ploiesti, Department of Mathematics and Computer Science (Romania)

2010-11-15T23:59:59.000Z

214

N=1 Super-symmetry Lagrangian in the de Sitter space  

E-Print Network [OSTI]

Previously, in [1], a novel N=1 super-symmetric algebra in de Sitter space-time was introduced. This paper is an attempt to build a proper N=1 super-symmetric field theory of classical level in the de Sitter space. The generators, gauge transformations and different fields in a 5-dimensional ambient space notation are defined and corresponding super-space and super-fields are introduced. Finally, the N=1 super-symmetry Lagrangian in the de Sitter ambient space notation has been

M. R. Masouminia

2014-05-14T23:59:59.000Z

215

Expediting model-based optoacoustic reconstructions with tomographic symmetries  

SciTech Connect (OSTI)

Purpose: Image quantification in optoacoustic tomography implies the use of accurate forward models of excitation, propagation, and detection of optoacoustic signals while inversions with high spatial resolution usually involve very large matrices, leading to unreasonably long computation times. The development of fast and memory efficient model-based approaches represents then an important challenge to advance on the quantitative and dynamic imaging capabilities of tomographic optoacoustic imaging. Methods: Herein, a method for simplification and acceleration of model-based inversions, relying on inherent symmetries present in common tomographic acquisition geometries, has been introduced. The method is showcased for the case of cylindrical symmetries by using polar image discretization of the time-domain optoacoustic forward model combined with efficient storage and inversion strategies. Results: The suggested methodology is shown to render fast and accurate model-based inversions in both numerical simulations andpost mortem small animal experiments. In case of a full-view detection scheme, the memory requirements are reduced by one order of magnitude while high-resolution reconstructions are achieved at video rate. Conclusions: By considering the rotational symmetry present in many tomographic optoacoustic imaging systems, the proposed methodology allows exploiting the advantages of model-based algorithms with feasible computational requirements and fast reconstruction times, so that its convenience and general applicability in optoacoustic imaging systems with tomographic symmetries is anticipated.

Lutzweiler, Christian; Deán-Ben, Xosé Luís; Razansky, Daniel, E-mail: dr@tum.de [Institute for Biological and Medical Imaging (IBMI), Helmholtz Center Munich, Ingolstädter Landstrasse 1, 85764 Neuherberg (Germany) [Institute for Biological and Medical Imaging (IBMI), Helmholtz Center Munich, Ingolstädter Landstrasse 1, 85764 Neuherberg (Germany); Faculty of Medicine, Technical University of Munich, Ismaninger Strasse 22, 81675 Munich (Germany)

2014-01-15T23:59:59.000Z

216

Geodesic spaces : momentum Groups : symmetry  

E-Print Network [OSTI]

Geodesic spaces : momentum :: Groups : symmetry Vaughan Pratt Stanford University BLAST 2010 a · b denoting b rotated 90 degrees about a. End of reprise. 3. This talk; Geodesic spaces At FMCS. as points evenly spaced along a geodesic , right distributivity expresses a symmetry of about an arbitrary

Pratt, Vaughan

217

COW test of the weak equivalence principle: A low-energy window to look into the noncommutative structure of space-time?  

E-Print Network [OSTI]

We construct the quantum mechanical model of the COW experiment assuming that the underlying space time has a granular structure, described by a canonical noncommutative algebra of coordinates $x^{\\mu}$. The time-space sector of the algebra is shown to add a mass-dependent contribution to the gravitational acceleration felt by neutron deBrogli waves measured in a COW experiment. This makes time-space noncommutativity a potential candidate for an apparent violation of WEP even if the ratio of the inertial mass $m_{i}$ and gravitational mass $m_{g}$ is a universal constant. The latest experimental result based on COW principle is shown to place an upper-bound several orders of magnitude stronger than the existing one on the time-space noncommutative parameter. We argue that the evidence of NC structure of space-time may be found if the COW-type experiment can be repeated with several particle species.

Anirban Saha

2013-06-18T23:59:59.000Z

218

A gauge-theoretic description of $?$-prolongations, and $?$-symmetries of differential equations  

E-Print Network [OSTI]

We consider generalized (possibly depending on fields as well as on space-time variables) gauge transformations and gauge symmetries in the context of general -- that is, possibly non variational nor covariant -- differential equations. In this case the relevant principal bundle admits the first jet bundle (of the phase manifold) as an associated bundle, at difference with standard Yang-Mills theories. We also show how in this context the recently introduced operation of $\\mu$-prolongation of vector fields (which generalizes the $\\la$-prolongation of Muriel and Romero), and hence $\\mu$-symmetries of differential equations, arise naturally. This is turn suggests several directions for further development. S0ome detailed examples are also given.

G. Gaeta

2009-01-20T23:59:59.000Z

219

Spectral theorem and partial symmetries  

SciTech Connect (OSTI)

A novel method of the decompositon of a quantum system's Hamiltonian is presented. In this approach the criterion of the decomposition is determined by the symmetries possessed by the sub-Hamiltonians. This procedure is rather generic and independent of the actual global symmetry, or the lack of it, of the full Hamilton operator. A detailed investigation of the time evolution of the various sub-Hamiltonians, therefore the change in time of the symmetry of the physical object, is presented for the case of a vibrator-plus-rotor model. Analytical results are illustrated by direct numerical calculations.

Gozdz, A. [University of Maria Curie-Sklodowska, Department of Mathematical Physics, Institute of Physics (Poland); Gozdz, M. [University of Maria Curie-Sklodowska, Department of Complex Systems and Neurodynamics, Institute of Informatics (Poland)

2012-10-15T23:59:59.000Z

220

Numerical Valuation of Discrete Barrier Options with  

E-Print Network [OSTI]

Numerical Valuation of Discrete Barrier Options with the Adaptive Mesh Model and Other Competing for discrete barrier options such that many methods have been suggested and declared to price discrete barrier options fast and accurately but no one can tell exactly that what method is the best. We also make

Chu, Hao-hua

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


221

Discrete and Hybrid Nonholonomy Antonio Bicchi1  

E-Print Network [OSTI]

Discrete and Hybrid Nonholonomy Antonio Bicchi1 , Alessia Marigo2 , and Benedetto Piccoli3 1 Centro such as cars, trucks with trailers, rolling 3D objects, underactuated mechanisms, satellites, etc., has made of systems, allowing for discrete and hybrid (mixed continuous and discrete) configurations and transi- tions

Piccoli, Benedetto

222

Crossovers between superconducting symmetry classes  

E-Print Network [OSTI]

We study the average density of states in a small metallic grain coupled to two superconductors with the phase difference $\\pi$, in a magnetic field. The spectrum of the low-energy excitations in the grain is described by the random matrix theory whose symmetry depends on the magnetic field strength and coupling to the superconductors. In the limiting cases, a pure superconducting symmetry class is realized. For intermediate magnetic fields or couplings to the superconductors, the system experiences a crossover between different symmetry classes. With the help of the supersymmetric sigma-model we derive the exact expressions for the average density of states in the crossovers between the symmetry classes A-C and CI-C.

V. A. Koziy; M. A. Skvortsov

2011-06-20T23:59:59.000Z

223

Negative Energy Solutions and Symmetries  

E-Print Network [OSTI]

We revisit the negative energy solutions of the Dirac equation, which become relevant at very high energies and study several symmetries which follow therefrom. The consequences are briefly examined.

Burra G. Sidharth

2011-04-01T23:59:59.000Z

224

VARIATIONAL ESTIMATES FOR DISCRETE SCHR  

E-Print Network [OSTI]

­dimensional discrete SchrË?odinger operator. We prove that if # ess (H) # [-2, 2], then H-H 0 is compact and # ess (H V = 0. One of our main results in this paper is Theorem 1. If # ess (H) # [-2, 2], then V (n) # 0 that # ess (H) = [-2, 2] if and only if V (n) # 0. Our motivation for this result came from two sources

225

Discretized configurations and partial partitions  

E-Print Network [OSTI]

We show that the discretized configuration space of $k$ points in the $n$-simplex is homotopy equivalent to a wedge of spheres of dimension $n-k+1$. This space is homeomorphic to the order complex of the poset of ordered partial partitions of $\\{1,\\...,n+1\\}$ with exactly $k$ parts. We also compute the Euler characteristic in two different ways, thereby obtaining a topological proof of a combinatorial recurrence satisfied by the Stirling numbers of the second kind.

Abrams, Aaron; Hower, Valerie

2010-01-01T23:59:59.000Z

226

Parity-time symmetry broken by point-group symmetry  

SciTech Connect (OSTI)

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.

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)] [INIFTA (UNLP, CCT La Plata-CONICET), División Química Teórica, Blvd. 113 S/N, Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina)

2014-04-15T23:59:59.000Z

227

Symmetry energy from nuclear multifragmentation  

E-Print Network [OSTI]

The ratio of symmetry energy coefficient to temperature $C_{sym}/T$ is extracted from different prescriptions using the isotopic as well as the isobaric yield distributions obtained in different projectile fragmentation reactions. It is found that the values extracted from our theoretical calculation agree with those extracted from the experimental data but they differ very much from the input value of the symmetry energy used. The best possible way to deduce the value of the symmetry energy coefficient is to use the fragment yield at the breakup stage of the reaction and it is better to use the grand canonical model for the fragmentation analysis. This is because the formulas that are used for the deduction of the symmetry energy coefficient are all derived in the framework of the grand canonical ensemble which is valid only at the break-up (equilibrium) condition. The yield of "cold" fragments either from the theoretical models or from experiments when used for extraction of the symmetry energy coefficient using these prescriptions might lead to the wrong conclusion.

Swagata Mallik; Gargi Chaudhuri

2013-01-23T23:59:59.000Z

228

Chiral Symmetry Breaking in Graphene  

E-Print Network [OSTI]

The question of whether the Coulomb interaction is strong enough to break the sublattice symmetry of un-doped graphene is discussed. We formulate a strong coupling expansion where the ground state of the Coulomb Hamiltonian is found exactly and the kinetic hopping Hamiltonian is treated as a perturbation. We argue that many of the properties of the resulting system would be shared by graphene with a Hubbard model interaction. In particular, the best candidate sublattice symmetry breaking ground state is an antiferromagnetic Mott insulator. We discuss the results of some numerical simulations which indicate that the Coulomb interaction is indeed subcritical. We also point out the curious fact that, if the electron did not have spin degeneracy, the tendency to break chiral symmetry would be much greater and even relatively weak Coulomb interactions would likely gap the spectrum.

Gordon W. Semenoff

2011-08-19T23:59:59.000Z

229

The Broken Symmetry of Time  

SciTech Connect (OSTI)

This paper seeks to clarify features of time asymmetry in terms of symmetry breaking. It is observed that, in general, a contingent situation or event requires the breaking of an underlying symmetry. The distinction between the universal anisotropy of temporal processes and the irreversibility of certain physical processes is clarified. It is also proposed that the Transactional Interpretation of quantum mechanics offers an effective way to explain general thermodynamic asymmetry in terms of the time asymmetry of radiation, where prior such efforts have fallen short.

Kastner, Ruth E. [Department of Philosophy, University of Maryland, College Park, MD 20742 (United States)

2011-11-29T23:59:59.000Z

230

Bell's Jump Process in Discrete Time  

E-Print Network [OSTI]

The jump process introduced by J. S. Bell in 1986, for defining a quantum field theory without observers, presupposes that space is discrete whereas time is continuous. In this letter, our interest is to find an analogous process in discrete time. We argue that a genuine analog does not exist, but provide examples of processes in discrete time that could be used as a replacement.

Jonathan Barrett; Matthew Leifer; Roderich Tumulka

2005-09-27T23:59:59.000Z

231

Robust Hydraulic Fracture Monitoring (HFM) of Multiple Time Overlapping Events Using a Generalized Discrete Radon Transform  

E-Print Network [OSTI]

In this work we propose a novel algorithm for multiple-event localization for Hydraulic Fracture Monitoring (HFM) through the exploitation of the sparsity of the observed seismic signal when represented in a basis consisting of space time propagators. We provide explicit construction of these propagators using a forward model for wave propagation which depends non-linearly on the problem parameters - the unknown source location and mechanism of fracture, time and extent of event, and the locations of the receivers. Under fairly general assumptions and an appropriate discretization of these parameters we first build an over-complete dictionary of generalized Radon propagators and assume that the data is well represented as a linear superposition of these propagators. Exploiting this structure we propose sparsity penalized algorithms and workflow for super-resolution extraction of time overlapping multiple seismic events from single well data.

Ely, Gregory

2013-01-01T23:59:59.000Z

232

Towards Industrial Strength Discrete Optimization via Simulation...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Towards Industrial Strength Discrete Optimization via Simulation: Multi-Fidelity Optimization and Data-Driven Robustness Event Sponsor: Mathematics and Computing Science - LANS...

233

Discrete particle transport in porous media : discrete observations of physical mechanisms influencing particle behavior  

E-Print Network [OSTI]

An understanding of how discrete particles in the micron to submicron range behave in porous media is important to a number of environmental problems. Discrete particle behavior in the interior of a porous medium is complex ...

Yoon, Joon Sik, 1973-

2005-01-01T23:59:59.000Z

234

Discrete analysis of stochastic NMR  

SciTech Connect (OSTI)

Stochastic NMR is an efficient technique for high field in vivo imaging and spectroscopic studies in cases where the peak rf power required may be prohibitively high for conventional pulsed NMR techniques. This dissertation presents a theoretical analysis of a stochastic NMR method of acquiring spectroscopy data. The spin system is excited with rf pulses where the flip angles or the phases of the pulses are samples of a discrete stochastic process. The method is formulated as a stochastic difference equation which is then converted to ordinary deterministic difference equations describing the input-output cross-correlation, average signal power and signal power spectrum. The solutions of these equations are used to evaluate the stochastic, technique in terms of peak rf power requirement, spectral distortions and signal-to-noise ratio. Experimental results are also presented which verify the results of the discrete analysis. The analysis shows that the maximum signal-to-noise ratio is achieved when the RMS flip angle is approximately the Ernst angle. When the RMS flip angle is below the Ernst angle, the input-output cross-correlation is a good estimate of the FID. Increase of excitation power causes line broadening. In addition, the use of random flip angle, fixed phase excitation causes a notch artifact and non-uniform response across the spectrum both of which are not found in two new types of excitation, the random phase excitation and the random quadrature excitation. The signal power spectrum is also a good estimate of the real spectrum. The approximation of the cross-correlation by a time average causes systematic noise. The amount of systematic noise is found to be significantly reduced when an entire maximum length sequence (MLS) is used for excitation. Noise-like distortion at high power MLS excitation is discovered to be related to the number of feedback paths in the MLS generator. 29 refs., 58 figs.

Wong, Sam Tak-Sum

1988-12-01T23:59:59.000Z

235

Testing Lorentz symmetry with atoms and Light  

E-Print Network [OSTI]

This article reports on the Fifth Meeting on CPT and Lorentz Symmetry, CPT'10, held at the end of June 2010 in Bloomington, Indiana, USA. The focus is on recent tests of Lorentz symmetry using atomic and optical physics.

Neil Russell

2011-09-04T23:59:59.000Z

236

Verifying Volume Rendering Using Discretization Error Analysis  

E-Print Network [OSTI]

Verifying Volume Rendering Using Discretization Error Analysis Tiago Etiene, Daniel Jo¨nsson, Timo--We propose an approach for verification of volume rendering correctness based on an analysis of the volume rendering integral, the basis of most DVR algorithms. With respect to the most common discretization

Kirby, Mike

237

Introduction Discrete-time autoregressive process  

E-Print Network [OSTI]

Introduction Discrete-time autoregressive process Continuous-time Ornstein-Uhlenbeck process Sharp large deviations for the non-stationary Ornstein-Uhlenbeck process Bernard Bercu Bordeaux University-Uhlenbeck process 1 / 46 #12;Introduction Discrete-time autoregressive process Continuous-time Ornstein

Di Girolami, Cristina

238

Extreme events in discrete nonlinear lattices  

E-Print Network [OSTI]

We perform statistical analysis on discrete nonlinear waves generated though modulational instability in the context of the Salerno model that interpolates between the intergable Ablowitz-Ladik (AL) equation and the nonintegrable discrete nonlinear Schrodinger (DNLS) equation. We focus on extreme events in the form of discrete rogue or freak waves that may arise as a result of rapid coalescence of discrete breathers or other nonlinear interaction processes. We find power law dependence in the wave amplitude distribution accompanied by an enhanced probability for freak events close to the integrable limit of the equation. A characteristic peak in the extreme event probability appears that is attributed to the onset of interaction of the discrete solitons of the AL equation and the accompanied transition from the local to the global stochasticity monitored through the positive Lyapunov exponent of a nonlinear map.

A. Maluckov; Lj. Hadzievski; N. Lazarides; G. P. Tsironis

2009-01-22T23:59:59.000Z

239

Symmetry examples in open quantum dynamics  

E-Print Network [OSTI]

Dependent symmetries, a new kind of symmetry of the open quantum dynamics of a subsystem, symmetries that depend on the situation of the subsystem in a larger closed system, are explored by looking at simple examples. Each symmetry implies a particular form for the results of the open dynamics. The forms exhibit the symmetries very simply. It is shown directly, without assuming anything about the symmetry, that the dynamics produces the form, but knowing the symmetry and the form it implies can reduce what needs to be done to work out the dynamics; pieces can be deduced from the symmetry rather that calculated from the dynamics. Symmetries can be related to constants of the motion in new ways. A quantity might be a dependent constant of the motion, constant only for particular situations of the subsystem in the larger system. In particular, a generator of dependent symmetries could represent a quantity that is a dependent constant of the motion for the same situations as for the symmetries. The examples present a variety of possibilities. Sometimes a generator of dependent symmetries does represent a dependent constant of the motion. Sometimes it does not. Sometimes no quantity is a dependent constant of the motion. Sometimes every quantity is.

Thomas F. Jordan; San Ha Seo

2014-08-19T23:59:59.000Z

240

Consistent Cosmology, Dynamic Relativity and Causal Quantum Mechanics as Unified Manifestations of the Symmetry of Complexity  

E-Print Network [OSTI]

The universal symmetry, or conservation, of complexity underlies any law or principle of system dynamics and describes the unceasing transformation of dynamic information into dynamic entropy as the unique way to conserve their sum, the total dynamic complexity. Here we describe the real world structure emergence and dynamics as manifestation of the universal symmetry of complexity of initially homogeneous interaction between two protofields. It provides the unified complex-dynamic, causally complete origin of physically real, 3D space, time, elementary particles, their properties (mass, charge, spin, etc.), quantum, relativistic, and classical behaviour, as well as fundamental interaction forces, including naturally quantized gravitation. The old and new cosmological problems (including "dark" mass and energy) are basically solved for this explicitly emerging, self-tuning world structure characterised by strictly positive (and large) energy-complexity. A general relation is obtained between the numbers of world dimensions and fundamental forces, excluding plausible existence of hidden dimensions. The unified, causally explained quantum, classical, and relativistic properties (and types of behaviour) are generalised to all higher levels of complex world dynamics. The real world structure, dynamics, and evolution are exactly reproduced by the probabilistic dynamical fractal, which is obtained as the truly complete general solution of a problem and the unique structure of the new mathematics of complexity. We outline particular, problem-solving applications of always exact, but irregularly structured symmetry of unreduced dynamic complexity to microworld dynamics, including particle physics, genuine quantum chaos, real nanobiotechnology, and reliable genomics.

Andrei P. Kirilyuk

2014-05-14T23:59:59.000Z

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


241

Continuous space-time transformations  

E-Print Network [OSTI]

We prove that every continuous map acting on the four-dimensional Minkowski space and preserving light cones in one direction only is either a Poincar\\'e similarity, that is, a product of a Lorentz transformation and a dilation, or it is of a very special degenerate form. In the presence of the continuity assumption the main tool in the proof is a basic result from the homotopy theory of spheres.

Clément de Seguins Pazzis; Peter Šemrl

2015-02-04T23:59:59.000Z

242

A Discrete Event Simulation Model For Unstructured Supervisory Control  

E-Print Network [OSTI]

A Discrete Event Simulation Model For Unstructured Supervisory Control Of Unmanned Vehicles Committee #12;2 A Discrete Event Simulation Model For Unstructured Supervisory Control Of Unmanned multipleoperator multiplevehicle discrete event simulation model (MOMUVDES) is developed which captures

Cummings, Mary "Missy"

243

Spontaneous symmetry breaking in Schroedinger lattices with two nonlinear sites  

SciTech Connect (OSTI)

We introduce discrete systems in the form of straight (infinite) and ring-shaped chains, with two symmetrically placed nonlinear sites. The systems can be implemented in nonlinear optics (as waveguiding arrays) and Bose-Einstein condensates (by means of an optical lattice). A full set of exact analytical solutions for symmetric, asymmetric, and antisymmetric localized modes is found, and their stability is investigated in a numerical form. The symmetry-breaking bifurcation, through which the asymmetric modes emerge from the symmetric ones, is found to be of the subcritical type. It is transformed into a supercritical bifurcation if the nonlinearity is localized in relatively broad domains around two central sites, and also in the ring of a small size, i.e., in effectively nonlocal settings. The family of antisymmetric modes does not undergo bifurcations and features both stable and unstable portions. The evolution of unstable localized modes is investigated by means of direct simulations. In particular, unstable asymmetric states, which exist in the case of the subcritical bifurcation, give rise to breathers oscillating between the nonlinear sites, thus restoring an effective dynamical symmetry between them.

Brazhnyi, Valeriy A.; Malomed, Boris A. [Centro de Fisica do Porto, Faculdade de Ciencias, Universidade do Porto, R. Campo Alegre 687, Porto 4169-007 (Portugal); ICFO-Institut de Ciencies Fotoniques, Universitat Politecnica de Catalunya, Mediterranean Technology Park, 08860 Castelldefels (Barcelona) (Spain) and Department of Physical Electronics, School of Electrical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel)

2011-05-15T23:59:59.000Z

244

Clifford modules and symmetries of topological insulators  

E-Print Network [OSTI]

We complete the classification of symmetry constraints on gapped quadratic fermion hamiltonians proposed by Kitaev. The symmetry group is supposed compact and can include arbitrary unitary or antiunitary operators in the Fock space that conserve the algebra of quadratic observables. We analyze the multiplicity spaces of {\\em real} irreducible representations of unitary symmetries in the Nambu space. The joint action of intertwining operators and antiunitary symmetries provides these spaces with the structure of Clifford module: we prove a one-to-one correspondence between the ten Altland-Zirnbauer symmetry classes of fermion systems and the ten Morita equivalence classes of real and complex Clifford algebras. The antiunitary operators, which occur in seven classes, are projectively represented in the Nambu space by unitary "chiral symmetries". The space of gapped symmetric hamiltonians is homotopically equivalent to the product of classifying spaces indexed by the dual object of the group of unitary symmetries.

Gilles Abramovici; Pavel Kalugin

2011-05-17T23:59:59.000Z

245

Spontaneous breaking of symmetry of the gravitons of the long wave spectrum in the early Universe  

E-Print Network [OSTI]

It is shown that nonlinear terms in equations of gravitons on the background of curved space-time of the expanding Universe can solve the problem of the negative square of the effective mass formally arising in linear approximation for gravitons. Similar to well known spontaneous breaking of symmetry in Goldstone model one must take another vacuum so that nonzero vacuum expectation value of the quantized graviton field leads to change of spectrum for gravitons. There appears two graviton fields, one with the positive mass, another with the zero mass. Energy density and the density of particles created by gravitation of the expanding Universe are calculated for some special cases of the scale factor. Numerical of result are obtained for the dust universe case.

A. A. Grib

2009-05-07T23:59:59.000Z

246

Localization and chiral symmetry in 2+1 flavor domain wall QCD  

SciTech Connect (OSTI)

We present results for the dependence of the residual mass of domain wall fermions (DWF) on the size of the fifth dimension and its relation to the density and localization properties of low-lying eigenvectors of the corresponding hermitian Wilson Dirac operator relevant to simulations of 2+1 flavor domain wall QCD. Using the DBW2 and Iwasaki gauge actions, we generate ensembles of configurations with a $16^3\\times 32$ space-time volume and an extent of 8 in the fifth dimension for the sea quarks. We demonstrate the existence of a regime where the degree of locality, the size of chiral symmetry breaking and the rate of topology change can be acceptable for inverse lattice spacings $a^{-1} \\ge 1.6$ GeV.

David J. Antonio; Kenneth C. Bowler; Peter A. Boyle; Norman H. Christ; Michael A. Clark; Saul D. Cohen; Chris Dawson; Alistair Hart; Balint Joó; Chulwoo Jung; Richard D. Kenway; Shu Li; Meifeng Lin; Robert D. Mawhinney; Christopher M. Maynard; Shigemi Ohta; Robert J. Tweedie; Azusa Yamaguchi

2008-01-01T23:59:59.000Z

247

From nothing to something: discrete integrable systems  

E-Print Network [OSTI]

Chinese ancient sage Laozi said that everything comes from `nothing'. Einstein believes the principle of nature is simple. Quantum physics proves that the world is discrete. And computer science takes continuous systems as discrete ones. This report is devoted to deriving a number of discrete models, including well-known integrable systems such as the KdV, KP, Toda, BKP, CKP, and special Viallet equations, from `nothing' via simple principles. It is conjectured that the discrete models generated from nothing may be integrable because they are identities of simple algebra, model-independent nonlinear superpositions of a trivial integrable system (Riccati equation), index homogeneous decompositions of the simplest geometric theorem (the angle bisector theorem), as well as the M\\"obious transformation invariants.

S Y Lou; Yu-qi Li; Xiao-yan Tang

2014-07-27T23:59:59.000Z

248

A discrete curvature on a planar graph  

E-Print Network [OSTI]

Given a planar graph derived from a spherical, euclidean or hyperbolic tessellation, one can define a discrete curvature by combinatorial properties, which after embedding the graph in a compact 2d-manifold, becomes the Gaussian curvature.

M. Lorente

2004-12-20T23:59:59.000Z

249

Port-Hamiltonian systems on discrete manifolds  

E-Print Network [OSTI]

This paper offers a geometric framework for modeling port-Hamiltonian systems on discrete manifolds. The simplicial Dirac structure, capturing the topological laws of the system, is defined in terms of primal and dual cochains related by the coboundary operators. This finite-dimensional Dirac structure, as discrete analogue of the canonical Stokes-Dirac structure, allows for the formulation of finite-dimensional port-Hamiltonian systems that emulate the behaviour of the open distributed-parameter systems with Hamiltonian dynamics.

Marko Seslija; Jacquelien M. A. Scherpen; Arjan van der Schaft

2012-01-27T23:59:59.000Z

250

R Symmetries in the Landscape  

E-Print Network [OSTI]

In the landscape, states with $R$ symmetries at the classical level form a distinct branch, with a potentially interesting phenomenology. Some preliminary analyses suggested that the population of these states would be significantly suppressed. We survey orientifolds of IIB theories compactified on Calabi-Yau spaces based on vanishing polynomials in weighted projective spaces, and find that the suppression is quite substantial. On the other hand, we find that a $Z_2$ R-parity is a common feature in the landscape. We discuss whether the cosmological constant and proton decay or cosmology might select the low energy branch. We include also some remarks on split supersymmetry.

M. Dine; Z. Sun

2005-06-28T23:59:59.000Z

251

Dynamics-dependent symmetries in Newtonian mechanics  

E-Print Network [OSTI]

We exhibit two symmetries of one-dimensional Newtonian mechanics whereby a solution is built from the history of another solution via a generally nonlinear and complex potential-dependent transformation of the time. One symmetry intertwines the square roots of the kinetic and potential energies and connects solutions of the same dynamical problem (the potential is an invariant function). The other symmetry connects solutions of different dynamical problems (the potential is a scalar function). The existence of corresponding conserved quantities is examined using Noethers theorem and it is shown that the invariant-potential symmetry is correlated with energy conservation. In the Hamilton-Jacobi picture the invariant-potential transformation provides an example of a field-dependent symmetry in point mechanics. It is shown that this transformation is not a symmetry of the Schroedinger equation.

Peter Holland

2014-09-19T23:59:59.000Z

252

Symmetry and Dirac points in graphene spectrum  

E-Print Network [OSTI]

Existence and stability of Dirac points in the dispersion relation of operators periodic with respect to the hexagonal lattice is investigated for different sets of additional symmetries. The following symmetries are considered: rotation by $2\\pi/3$ and inversion, rotation by $2\\pi/3$ and horizontal reflection, inversion or reflection with weakly broken rotation symmetry, and the case where no Dirac points arise: rotation by $2\\pi/3$ and vertical reflection. All proofs are based on symmetry considerations and are elementary in nature. In particular, existence of degeneracies in the spectrum is proved by a transplantation argument (which is deduced from the (co)representation of the relevant symmetry group). The conical shape of the dispersion relation is obtained from its invariance under rotation by $2\\pi/3$. Persistence of conical points when the rotation symmetry is weakly broken is proved using a geometric phase in one case and parity of the eigenfunctions in the other.

Gregory Berkolaiko; Andrew Comech

2014-12-28T23:59:59.000Z

253

Inflation, Symmetry, and B-Modes  

E-Print Network [OSTI]

We examine the role of using symmetry and effective field theory in inflationary model building. We describe the standard formulation of starting with an approximate shift symmetry for a scalar field, and then introducing corrections systematically in order to maintain control over the inflationary potential. We find that this leads to models in good agreement with recent data. On the other hand, there are attempts in the literature to deviate from this paradigm by envoking other symmetries and corrections. In particular: in a suite of recent papers, several authors have made the claim that standard Einstein gravity with a cosmological constant and a massless scalar carries conformal symmetry. They further claim that such a theory carries another hidden symmetry; a global SO(1,1) symmetry. By deforming around the global SO(1,1) symmetry, they are able to produce a range of inflationary models with asymptotically flat potentials, whose flatness is claimed to be protected by these symmetries. These models tend to give rise to B-modes with small amplitude. Here we explain that these authors are merely introducing a redundancy into the description, not an actual conformal symmetry. Furthermore, we explain that the only real (global) symmetry in these models is not at all hidden, but is completely manifest when expressed in the Einstein frame; it is in fact the shift symmetry of a scalar field. When analyzed systematically as an effective field theory, deformations do not generally produce asymptotically flat potentials and small B-modes, but other types of potentials with B-modes of large amplitude; nicely compatible with recent BICEP2 data. Such simple models typically also produce the observed red spectral index, Gaussian fluctuations, etc. In short: simple models of inflation, organized by expanding around a shift symmetry, are in excellent agreement with recent data.

Mark P. Hertzberg

2014-03-20T23:59:59.000Z

254

Breaking Parity Symmetry Using Extra Dimensions  

E-Print Network [OSTI]

We present a new way to break parity symmetry in left-right symmetric models using boundary conditions on the fields residing in the fifth dimension. We also discuss the connection between the limits on the size of extra dimensions and the scale of right handed symmetry breaking obtained from the analysis of neutrinoless double beta decay in the case where the righthanded gauge symmetry is in the bulk.

R. N. Mohapatra; A. Pérez-Lorenzana

1999-11-17T23:59:59.000Z

255

Contact Symmetries and Hamiltonian Thermodynamics  

E-Print Network [OSTI]

It has been shown that contact geometry is the proper framework underlying classical thermodynamics and that thermodynamic fluctuations are captured by an additional metric structure related to Fisher's Information Matrix. In this work we analyze several unaddressed aspects about the application of contact and metric geometry to thermodynamics. We consider here the Thermodynamic Phase Space and start by investigating the role of gauge transformations and Legendre symmetries for metric contact manifolds and their significance in thermodynamics. Then we present a novel mathematical characterization of first order phase transitions as equilibrium processes on the Thermodynamic Phase Space for which the Legendre symmetry is broken. Moreover, we use contact Hamiltonian dynamics to represent thermodynamic processes in a way that resembles the classical Hamiltonian formulation of conservative mechanics and we show that the relevant Hamiltonian coincides with the irreversible entropy production along thermodynamic processes. Therefore, we use such property to give a geometric definition of thermodynamically admissible fluctuations according to the Second Law of thermodynamics. Finally, we show that the length of a curve describing a thermodynamic process measures its entropy production.

A. Bravetti; C. S. Lopez-Monsalvo; F. Nettel

2015-02-22T23:59:59.000Z

256

Energy Levels of "Hydrogen Atom" in Discrete Time Dynamics  

E-Print Network [OSTI]

We analyze dynamical consequences of a conjecture that there exists a fundamental (indivisible) quant of time. In particular we study the problem of discrete energy levels of hydrogen atom. We are able to reconstruct potential which in discrete time formalism leads to energy levels of unperturbed hydrogen atom. We also consider linear energy levels of quantum harmonic oscillator and show how they are produced in the discrete time formalism. More generally, we show that in discrete time formalism finite motion in central potential leads to discrete energy spectrum, the property which is common for quantum mechanical theory. Thus deterministic (but discrete time!) dynamics is compatible with discrete energy levels.

Andrei Khrennikov; Yaroslav Volovich

2006-04-27T23:59:59.000Z

257

Symmetry energy in nuclear density functional theory  

E-Print Network [OSTI]

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

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

2013-07-22T23:59:59.000Z

258

Issues in standard model symmetry breaking  

SciTech Connect (OSTI)

This work discusses the symmetry breaking sector of the SU(2) x U(1) electroweak model. The first two chapters discuss Higgs masses in two simple Higgs models. The author proves low-enery theorems for the symmetry breaking sector: The threshold behavior of gauge-boson scattering is completely determined, whenever the symmetry breaking sector meets certain simple conditions. The author uses these theorems to derive event rates for the superconducting super collider (SSC). The author shows that the SSC may be able to determine whether the interactions of the symmetry breaking sector are strong or weak. 54 refs.

Golden, M.

1988-04-01T23:59:59.000Z

259

A H-infinity Fault Detection and Diagnosis Scheme for Discrete Nonlinear System Using Output Probability Density Estimation  

SciTech Connect (OSTI)

In this paper, a H-infinity fault detection and diagnosis (FDD) scheme for a class of discrete nonlinear system fault using output probability density estimation is presented. Unlike classical FDD problems, the measured output of the system is viewed as a stochastic process and its square root probability density function (PDF) is modeled with B-spline functions, which leads to a deterministic space-time dynamic model including nonlinearities, uncertainties. A weighting mean value is given as an integral function of the square root PDF along space direction, which leads a function only about time and can be used to construct residual signal. Thus, the classical nonlinear filter approach can be used to detect and diagnose the fault in system. A feasible detection criterion is obtained at first, and a new H-infinity adaptive fault diagnosis algorithm is further investigated to estimate the fault. Simulation example is given to demonstrate the effectiveness of the proposed approaches.

Zhang Yumin; Lum, Kai-Yew [Temasek Laboratories, National University of Singapore, Singapore 117508 (Singapore); Wang Qingguo [Depa. Electrical and Computer Engineering, National University of Singapore, Singapore 117576 (Singapore)

2009-03-05T23:59:59.000Z

260

Electroweak Symmetry Breaking via QCD  

E-Print Network [OSTI]

We propose a new mechanism to generate the electroweak scale within the framework of QCD, which is extended to include conformally invariant scalar degrees of freedom belonging to a larger irreducible representation of $SU(3)_c$. The electroweak symmetry breaking is triggered dynamically via the Higgs portal by the condensation of the colored scalar field around 1 TeV. The mass of the colored boson is restricted to be 350 GeV $\\lesssim m_S\\lesssim $ 3 TeV, with the upper bound obtained from perturbative renormalization group evolution. This implies that the colored boson can be produced at LHC. If the colored boson is electrically charged, the branching fraction of the Higgs decaying into two photons can slightly increase, and moreover, it can be produced at future linear colliders. Our idea of non-perturbative EW scale generation can serve as a new starting point for more realistic model building in solving the hierarchy problem.

Jisuke Kubo; Kher Sham Lim; Manfred Lindner

2014-09-01T23:59:59.000Z

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


261

On systems having Poincaré and Galileo symmetry  

E-Print Network [OSTI]

Using the wave equation in d > or = 1 space dimensions it is illustrated how dynamical equations may be simultaneously Poincar\\'e and Galileo covariant with respect to different sets of independent variables. This provides a method to obtain dynamics-dependent representations of the kinematical symmetries. When the field is a displacement function both symmetries have a physical interpretation. For d = 1 the Lorentz structure is utilized to reveal hitherto unnoticed features of the non-relativistic Chaplygin gas, including a relativistic structure with a limiting case that exhibits the Carroll group, and field-dependent symmetries and associated Noether charges. The Lorentz transformations of the potentials naturally associated with the Chaplygin system are given. These results prompt the search for further symmetries and it is shown that the Chaplygin equations support a nonlinear superposition principle. A known spacetime mixing symmetry is shown to decompose into label-time and superposition symmetries. It is shown that a quantum mechanical system in a stationary state behaves as a Chaplygin gas. The extension to d > 1 is used to illustrate how the physical significance of the dual symmetries is contingent on the context by showing that Maxwells equations exhibit an exact Galileo covariant formulation where Lorentz and gauge transformations are represented by field-dependent symmetries. A natural conceptual and formal framework is provided by the Lagrangian and Eulerian pictures of continuum mechanics.

Peter Holland

2014-11-13T23:59:59.000Z

262

Local symmetries of non-expanding horizons  

E-Print Network [OSTI]

Local symmetries of a non-expanding horizon has been investigated in the 1st order formulation of gravity. When applied to a spherically symmetric isolated horizon only a U(1) subgroup of the Lorentz group survives as residual local symmetry that one can make use of in constructing an effective theory on the horizon.

Rudranil Basu; Ayan Chatterjee; Amit Ghosh

2010-04-21T23:59:59.000Z

263

Is chiral symmetry manifested in nuclear structure?  

E-Print Network [OSTI]

Spontaneously broken chiral symmetry is an established property of low-energy quantum chromodynamics, but finding direct evidence for it from nuclear structure data is a difficult challenge. Indeed, phenomenologically successful energy-density functional approaches do not even have explicit pions. Are there smoking guns for chiral symmetry in nuclei?

R. J. Furnstahl; A. Schwenk

2010-01-02T23:59:59.000Z

264

Reducing Symmetry in Matrix Models # Zeynep Kzltan  

E-Print Network [OSTI]

University, Sweden Zeynep.Kiziltan@dis.uu.se 1 Introduction Symmetry in a CSP model is an important issue as the exploration of symmetric but essentially equivalent branches in a search tree may significantly slow down developed so as to address the issue of eliminating symmetry in CSP models. Many CSPs can be modelled

Rossi, Francesca

265

Symmetry-Breaking Constraints for Matrix Models  

E-Print Network [OSTI]

-breaking constraints. Experimental re- sults confirm their value. 1 Introduction Symmetry in a CSP model is an important issue as the exploration of symmet- ric but essentially equivalent branches in a search tree may techniques have been developed to address the issue of eliminating symmetry in CSP models. An important class

Flener, Pierre

266

The Symmetry, Color, and Morphology of Galaxies  

E-Print Network [OSTI]

The structural symmetry of forty-three face-on galaxy images in the R(65 0 nm) and J(450 nm) bands are measured to determine the usefulness of symmetry a s a morphological parameter. Each galaxy image is rotated by $180$\\deg and subtr acted from the original to obtain a quantitative value for its structural symmet ry. The symmetry numbers computed for the sample are then compared with RC3 mor phological types, color \\& absolute blue magnitudes. A strong correlation betw een color and symmetry is found, and the RC3 Hubble sequence is found to be one of increasing asymmetry. The use of symmetry as a morphological parameter, and the possible causes of the asymmetries are discussed.

Christopher J. Conselice

1997-10-22T23:59:59.000Z

267

Noether theorem for mu-symmetries  

E-Print Network [OSTI]

We give a version of Noether theorem adapted to the framework of mu-symmetries; this extends to such case recent work by Muriel, Romero and Olver in the framework of lambda-symmetries, and connects mu-symmetries of a Lagrangian to a suitably modified conservation law. In some cases this "mu-conservation law'' actually reduces to a standard one; we also note a relation between mu-symmetries and conditional invariants. We also consider the case where the variational principle is itself formulated as requiring vanishing variation under mu-prolonged variation fields, leading to modified Euler-Lagrange equations. In this setting mu-symmetries of the Lagrangian correspond to standard conservation laws as in the standard Noether theorem. We finally propose some applications and examples.

G. Cicogna; G. Gaeta

2007-08-23T23:59:59.000Z

268

Exploiting Matrix Symmetries and Physical Symmetries in Matrix Product States and Tensor Trains  

E-Print Network [OSTI]

We focus on symmetries related to matrices and vectors appearing in the simulation of quantum many-body systems. Spin Hamiltonians have special matrix-symmetry properties such as persymmetry. Furthermore, the systems may exhibit physical symmetries translating into symmetry properties of the eigenvectors of interest. Both types of symmetry can be exploited in sparse representation formats such as Matrix Product States (MPS) for the desired eigenvectors. This paper summarizes symmetries of Hamiltonians for typical physical systems such as the Ising model and lists resulting properties of the related eigenvectors. Based on an overview of Matrix Product States (Tensor Trains or Tensor Chains) and their canonical normal forms we show how symmetry properties of the vector translate into relations between the MPS matrices and, in turn, which symmetry properties result from relations within the MPS matrices. In this context we analyze different kinds of symmetries and derive appropriate normal forms for MPS representing these symmetries. Exploiting such symmetries by using these normal forms will lead to a reduction in the number of degrees of freedom in the MPS matrices. This paper provides a uniform platform for both well-known and new results which are presented from the (multi-)linear algebra point of view.

T. Huckle; K. Waldherr; T. Schulte-Herbrueggen

2013-01-04T23:59:59.000Z

269

Discrete Optimization A simulated annealing approach  

E-Print Network [OSTI]

for the constrained and the unconstrained circular cutting problem based upon simulated annealing. We define an energyDiscrete Optimization A simulated annealing approach for the circular cutting problem Mhand Hifi corner of the initial rectangle. Such values of the energy correspond to configurations where pieces

Zissimopoulos, Vassilis

270

Massively Parallel Computation of Discrete Logarithms \\Lambda  

E-Print Network [OSTI]

an order of magnitude using such an analysis. Among the reasons for this are: ffl if a high­level language, keeping in mind that log g a is only determined modulo the multiplicative order of g. For general be extremely useful to chart the increase in difficulty of computing discrete logarithms as the field size

McCurley, Kevin

271

Massively Parallel Computation of Discrete Logarithms  

E-Print Network [OSTI]

an order of magnitude using such an analysis. Among the reasons for this are: · if a high-level language, keeping in mind that logg a is only determined modulo the multiplicative order of g. For general be extremely useful to chart the increase in difficulty of computing discrete logarithms as the field size

Gordon, Dan

272

Comment on ``Discrete Boltzmann Equation for Microfluidics''  

E-Print Network [OSTI]

Comment on ``Discrete Boltzmann Equation for Microfluidics'' In a recent Letter [1], Li and Kwok use a lattice Boltzmann equation (LBE) for microfluidics. Their main claim is that an LBE model for microfluidics can be constructed based on the ``Bhatnagar-Gross-Kooky [sic]'' model by including ``the

Luo, Li-Shi

273

Quantum Gravity Phenomenology, Lorentz Invariance and Discreteness  

E-Print Network [OSTI]

Quantum Gravity Phenomenology, Lorentz Invariance and Discreteness Fay Dowker #3; , Joe Henson y invariant, and we recall the reasons why. For illustration, we introduce a phenomenological model of massive { LLI violating phenomenological e#11;ects of quantum gravity { has grown up around this idea

Sorkin, Rafael Dolnick

274

Fast mix table construction for material discretization  

SciTech Connect (OSTI)

An effective hybrid Monte Carlo-deterministic implementation typically requires the approximation of a continuous geometry description with a discretized piecewise-constant material field. The inherent geometry discretization error can be reduced somewhat by using material mixing, where multiple materials inside a discrete mesh voxel are homogenized. Material mixing requires the construction of a 'mix table,' which stores the volume fractions in every mixture so that multiple voxels with similar compositions can reference the same mixture. Mix table construction is a potentially expensive serial operation for large problems with many materials and voxels. We formulate an efficient algorithm to construct a sparse mix table in O(number of voxels x log number of mixtures) time. The new algorithm is implemented in ADVANTG and used to discretize continuous geometries onto a structured Cartesian grid. When applied to an end-of-life MCNP model of the High Flux Isotope Reactor with 270 distinct materials, the new method improves the material mixing time by a factor of 100 compared to a naive mix table implementation. (authors)

Johnson, S. R. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

2013-07-01T23:59:59.000Z

275

All-optical discrete vortex switch  

SciTech Connect (OSTI)

We introduce discrete vortex solitons and vortex breathers in circular arrays of nonlinear waveguides. The simplest vortex breather in a four-waveguide coupler is a nonlinear dynamic state changing its topological charge between +1 and -1 periodically during propagation. We find the stability domain for this solution and suggest an all-optical vortex switching scheme.

Desyatnikov, Anton S. [Nonlinear Physics Center, Research School of Physics and Engineering, Australian National University, Canberra, ACT 0200 (Australia); Dennis, Mark R. [H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Ferrando, Albert [Interdisciplinary Modeling Group, InterTech and Departament d'Optica, Universitat de Valencia, E-46100 Burjassot (Spain)

2011-06-15T23:59:59.000Z

276

On the discrete bicycle transformation S. Tabachnikov  

E-Print Network [OSTI]

On the discrete bicycle transformation S. Tabachnikov E. Tsukerman 1 Introduction The motivation for this paper comes from the study of a simple model of bicycle motion. The bicycle is modeled as an oriented segment in the plane of fixed length , the wheelbase of the bicycle. The motion is constrained so

Tabachnikov, Sergei

277

Symmetry-Driven Spontaneous Self-assembly of Nanoscale Ceria...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Symmetry-Driven Spontaneous Self-assembly of Nanoscale Ceria Building Blocks to Fractal Super-octahedra. Symmetry-Driven Spontaneous Self-assembly of Nanoscale Ceria Building...

278

Does Symmetry Imply PPT Property?  

E-Print Network [OSTI]

Recently, in [1], the author proved that many results that are true for PPT matrices also hold for another class of matrices with a certain symmetry in their Hermitian Schmidt decompositions. These matrices were called SPC in [1] (definition 1.1). Before that, in [9], T\\'oth and G\\"uhne proved that if a state is symmetric then it is PPT if and only if it is SPC. A natural question appeared: What is the connection between SPC matrices and PPT matrices? Is every SPC matrix PPT? Here we show that every SPC matrix is PPT in $M_2\\otimes M_2$ (theorem 4.3). This theorem is a consequence of the fact that every density matrix in $M_2\\otimes M_m$, with tensor rank smaller or equal to 3, is separable (theorem 3.2). This theorem is a generalization of the same result found in [1] for tensor rank 2 matrices in $M_k\\otimes M_m$. Although, in $M_3\\otimes M_3$, there exists a SPC matrix with tensor rank 3 that is not PPT (proposition 5.2). We shall also provide a non trivial example of a family of matrices in $M_k\\otimes M_k$, in which both, the SPC and PPT properties, are equivalent (proposition 6.2). Within this family, there exists a non trivial subfamily in which the SPC property is equivalent to separability (proposition 6.4).

Daniel Cariello

2014-05-14T23:59:59.000Z

279

Graphene, Lattice QFT and Symmetries  

E-Print Network [OSTI]

Borrowing ideas from tight binding model, we propose a board class of Lattice QFT models that are classified by the ADE Lie algebras. In the case of su(N) series, we show that the couplings between the quantum states living at the first nearest neighbor sites of the lattice $\\mathcal{L}_{su(N)}$ are governed by the complex fundamental representations \\underline{${{\\mathbf{N}}}$} and $\\bar{{\\mathbf{N}}}$ of $su(N)$; and the second nearest neighbor interactions are described by its adjoint $\\underline{\\mathbf{N}} \\otimes \\bar{\\mathbf{N}}$. The lattice models associated with the leading su(2), su(3) and su(4) cases are explicitly studied and their fermionic field realizations are given. It is also shown that the su(2) and su(3) models describe respectively the electronic properties of the acetylene chain and the graphene. It is established as well that the energy dispersion of the first nearest neighbor couplings is completely determined by the $A_{N}$ roots $ \\mathbf{\\alpha}$ through the typical dependence $N/2+\\sum_{roots}\\cos(\\mathbf{k}.\\alpha) $ with $\\mathbf{k}$ the wave vector. Other features such as DE extension and other applications are also discussed. Keywords: Tight Binding Model, Graphene, Lattice QFT, ADE Symmetries.

L. B Drissi; E. H Saidi; M. Bousmina

2011-03-07T23:59:59.000Z

280

High density behaviour of nuclear symmetry energy  

E-Print Network [OSTI]

Role of the isospin asymmetry in nuclei and neutron stars, with an emphasis on the density dependence of the nuclear symmetry energy, is discussed. The symmetry energy is obtained using the isoscalar as well as isovector components of the density dependent M3Y effective interaction. The constants of density dependence of the effective interaction are obtained by reproducing the saturation energy per nucleon and the saturation density of spin and isospin symmetric cold infinite nuclear matter. Implications for the density dependence of the symmetry energy in case of a neutron star are discussed, and also possible constraints on the density dependence obtained from finite nuclei are compared.

D. N. Basu; Tapan Mukhopadhyay

2006-12-27T23:59:59.000Z

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


281

Discrete Spectral Transformations of Skew Orthogonal Polynomials and Associated Discrete Integrable Systems  

E-Print Network [OSTI]

Discrete spectral transformations of skew orthogonal polynomials are presented. From these spectral transformations, it is shown that the corresponding discrete integrable systems are derived both in 1+1 dimension and in 2+1 dimension. Especially in the (2+1)-dimensional case, the corresponding system can be extended to 2x2 matrix form. The factorization theorem of the Christoffel kernel for skew orthogonal polynomials in random matrix theory is presented as a by-product of these transformations.

Hiroshi Miki; Hiroaki Goda; Satoshi Tsujimoto

2012-02-29T23:59:59.000Z

282

Discrete spectral transformations of skew orthogonal polynomials and associated discrete integral systems  

E-Print Network [OSTI]

Discrete spectral transformations of skew orthognal polynomials are presented. From these spectral transformations, it is shown that the corresponding discrete integrable systems are derived both in 1+1 dimension and in 2+1 dimension. Especially in the 2+1 dimensional case, the corresponding system can be extended to 2x2 matrix form. The factorization theorem of the skew-Christoffel kernel in random matrix theory is presented as a by-product of these transformations.

Miki, Hiroshi; Tsujimoto, Satoshi

2011-01-01T23:59:59.000Z

283

Second order symmetry-preserving conservative Lagrangian scheme for compressible Euler equations in two-dimensional cylindrical coordinates  

SciTech Connect (OSTI)

In applications such as astrophysics and inertial confinement fusion, there are many three-dimensional cylindrical-symmetric multi-material problems which are usually simulated by Lagrangian schemes in the two-dimensional cylindrical coordinates. For this type of simulation, a critical issue for the schemes is to keep spherical symmetry in the cylindrical coordinate system if the original physical problem has this symmetry. In the past decades, several Lagrangian schemes with such symmetry property have been developed, but all of them are only first order accurate. In this paper, we develop a second order cell-centered Lagrangian scheme for solving compressible Euler equations in cylindrical coordinates, based on the control volume discretizations, which is designed to have uniformly second order accuracy and capability to preserve one-dimensional spherical symmetry in a two-dimensional cylindrical geometry when computed on an equal-angle-zoned initial grid. The scheme maintains several good properties such as conservation for mass, momentum and total energy, and the geometric conservation law. Several two-dimensional numerical examples in cylindrical coordinates are presented to demonstrate the good performance of the scheme in terms of accuracy, symmetry, non-oscillation and robustness. The advantage of higher order accuracy is demonstrated in these examples.

Cheng, Juan, E-mail: cheng_juan@iapcm.ac.cn [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Shu, Chi-Wang, E-mail: shu@dam.brown.edu [Division of Applied Mathematics, Brown University, Providence, RI 02912 (United States)

2014-09-01T23:59:59.000Z

284

Math 209 Discrete Mathematics Spring 2008 Instructor Amites Sarkar  

E-Print Network [OSTI]

Math 209 Discrete Mathematics Spring 2008 Instructor Amites Sarkar Text Discrete Mathematics, Tuesdays, Thursdays and Fridays, in 216 Bond Hall. My phone number is 650 7569 and my e-mail is amites.sarkar

Sarkar, Amites

285

Math 209 Discrete Mathematics Spring 2011 Instructor Dr. Amites Sarkar  

E-Print Network [OSTI]

Math 209 Discrete Mathematics Spring 2011 Instructor Dr. Amites Sarkar Text Discrete Mathematics, in 216 Bond Hall. My phone number is 650 7569 and my e-mail is amites.sarkar@wwu.edu #12;

Sarkar, Amites

286

Math 209 Discrete Mathematics Winter 2009 Instructor Amites Sarkar  

E-Print Network [OSTI]

Math 209 Discrete Mathematics Winter 2009 Instructor Amites Sarkar Text Discrete Mathematics, Tuesdays, Thursdays and Fridays, in 216 Bond Hall. My phone number is 650 7569 and my e-mail is amites.sarkar

Sarkar, Amites

287

Localized waves with spherical harmonic symmetries  

E-Print Network [OSTI]

We introduce a class of propagation invariant spatiotemporal optical wave packets with spherical harmonic symmetries in their field configurations. The evolution of these light orbitals is considered theoretically in ...

Mills, M. S.

288

Particle-hole symmetry parameters for nuclei  

E-Print Network [OSTI]

Two parameters, nu and zeta, motivated by particle-hole symmetry are introduced. These parameters are determined using the number of proton (or neutron) particles and holes counted from neighboring shell closures. The new parameters can be used to evaluate particle-hole and proton-neutron symmetries of adopted B(E2) values, which indicate that both symmetries are approximate for A>100. The combined symmetries motivate empirical fits of binding energies and the energy ratio E(4_1^+)/E(2_1^+). A global binding energy fit consisting of a traditional liquid droplet and one new shell term, comprised of a function of nu and zeta, reproduces the experimental binding energies of 2353 nuclei with an r.m.s. standard deviation of 1.55 MeV.

Ian Bentley

2015-03-10T23:59:59.000Z

289

Symmetries and Interaction coefficients of Kelvin waves  

E-Print Network [OSTI]

We considered symmetry restriction on the interaction coefficients of Kelvin waves and demonstrated that linear in small wave vector asymptotic is not forbidden, as one can expect by naive reasoning.

Vladimir V. Lebedev; Victor S. L'vov

2010-05-25T23:59:59.000Z

290

Symmetry energy coefficients for asymmetric nuclear matter  

E-Print Network [OSTI]

Symmetry energy coefficients of asymmetric nuclear matter are investigated as the inverse of nuclear matter polarizabilities with two different approaches. Firstly a general calculation shows they may depend on the neutron-proton asymmetry itself. The choice of particular prescriptions for the density fluctuations lead to certain isospin (n-p asymmetry) dependences of the polarizabilities. Secondly, with Skyrme type interactions, the static limit of the dynamical polarizability is investigated corresponding to the inverse symmetry energy coefficient which assumes different values at different asymmetries (and densities and temperatures). The symmetry energy coefficient (in the isovector channel) is found to increase as n-p asymmetries increase. The spin symmetry energy coefficient is also briefly investigated.

Fábio L. Braghin

2003-12-16T23:59:59.000Z

291

Asymptotic symmetries in an optical lattice  

E-Print Network [OSTI]

It was recently remarked by Lutz [{\\it Phys. Rev. A} {\\bf 67} (2003), 051402(R)] that the equation for the marginal Wigner distribution in an optical lattice admits a scale-free distribution corresponding to Tsallis statistics. Here we show that this distribution is invariant under an asymptotic symmetry of the equation, hence that this scale-free behavior can be understood in terms of symmetry analysis.

G. Gaeta

2005-10-02T23:59:59.000Z

292

Fractional Zaslavsky and Henon Discrete Maps  

E-Print Network [OSTI]

This paper is devoted to the memory of Professor George M. Zaslavsky passed away on November 25, 2008. In the field of discrete maps, George M. Zaslavsky introduced a dissipative standard map which is called now the Zaslavsky map. G. Zaslavsky initialized many fundamental concepts and ideas in the fractional dynamics and kinetics. In this paper, starting from kicked damped equations with derivatives of non-integer orders we derive a fractional generalization of discrete maps. These fractional maps are generalizations of the Zaslavsky map and the Henon map. The main property of the fractional differential equations and the correspondent fractional maps is a long-term memory and dissipation. The memory is realized by the fact that their present state evolution depends on all past states with special forms of weights.

Vasily E. Tarasov

2011-07-26T23:59:59.000Z

293

A combinatorial approach to discrete geometry  

E-Print Network [OSTI]

We present a paralell approach to discrete geometry: the first one introduces Voronoi cell complexes from statistical tessellations in order to know the mean scalar curvature in term of the mean number of edges of a cell. The second one gives the restriction of a graph from a regular tessellation in order to calculate the curvature from pure combinatorial properties of the graph. Our proposal is based in some epistemological pressupositions: the macroscopic continuous geometry is only a fiction, very usefull for describing phenomena at certain sacales, but it is only an approximation to the true geometry. In the discrete geometry one starts from a set of elements and the relation among them without presuposing space and time as a background.

L. Bombelli; M. Lorente

2005-12-23T23:59:59.000Z

294

DOS: the discrete-ordinates system. [LMFBR  

SciTech Connect (OSTI)

The Discrete Ordinates System determines the flux of neutrons or photons due either to fixed sources specified by the user or to sources generated by particle interaction with the problem materials. It also determines numerous secondary results which depend upon flux. Criticality searches can be performed. Numerous input, output, and file manipulation facilities are provided. The DOS driver program reads the problem specification from an input file and calls various program modules into execution as specified by the input file.

Rhoades, W. A.; Emmett, M. B.

1982-09-01T23:59:59.000Z

295

An essay on discrete foundations for physics  

SciTech Connect (OSTI)

We base our theory of physics and cosmology on the five principles of finiteness, discreteness, finite computability, absolute non- uniqueness, and strict construction. Our modeling methodology starts from the current practice of physics, constructs a self-consistent representation based on the ordering operator calculus and provides rules of correspondence that allow us to test the theory by experiment. We use program universe to construct a growing collection of bit strings whose initial portions (labels) provide the quantum numbers that are conserved in the events defined by the construction. The labels are followed by content strings which are used to construct event-based finite and discrete coordinates. On general grounds such a theory has a limiting velocity, and positions and velocities do not commute. We therefore reconcile quantum mechanics with relativity at an appropriately fundamental stage in the construction. We show that events in different coordinate systems are connected by the appropriate finite and discrete version of the Lorentz transformation, that 3-momentum is conserved in events, and that this conservation law is the same as the requirement that different paths can ''interfere'' only when they differ by an integral number of deBroglie wavelengths. 38 refs., 12 figs., 3 tabs.

Noyes, H.P.; McGoveran, D.O.

1988-10-05T23:59:59.000Z

296

Nonzero {theta}{sub 13} for neutrino mixing in a supersymmetric B-L gauge model with T{sub 7} lepton flavor symmetry  

SciTech Connect (OSTI)

We discuss how {theta}{sub 13}{ne}0 is accommodated in a recently proposed renormalizable model of neutrino mixing using the non-Abelian discrete symmetry T{sub 7} in the context of a supersymmetric extension of the standard model with gauged U(1){sub B-L}. We predict a correlation between {theta}{sub 13} and {theta}{sub 23}, as well as the effective neutrino mass m{sub ee} in neutrinoless double beta decay.

Cao Qinghong [Department of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); High Energy Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, U.S.A (United States); Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637 (United States); Khalil, Shaaban [Centre for Theoretical Physics, The British University in Egypt, El Sherouk City, Postal No. 11837, P.O. Box 43 (Egypt); Department of Mathematics, Ain Shams University, Faculty of Science, Cairo 11566 (Egypt); Ma, Ernest [Department of Physics and Astronomy, University of California, Riverside, California 92521 (United States); Okada, Hiroshi [School of Physics, KIAS, Seoul 130-722 (Korea, Republic of)

2011-10-01T23:59:59.000Z

297

Symmetry Energy I: Semi-Infinite Matter  

E-Print Network [OSTI]

Energy for a nucleus is considered in macroscopic limit, in terms of nucleon numbers. Further considered for a nuclear system is the Hohenberg-Kohn energy functional, in terms of proton and neutron densities. Finally, Skyrme-Hartree-Fock calculations are carried out for a half-infinite particle-stable nuclear-matter. In each case, the attention is focused on the role of neutron-proton asymmetry and on the nuclear symmetry energy. We extend the considerations on the symmetry term from an energy formula to the respective term in the Hohenberg-Kohn functional. We show, in particular, that in the limit of an analytic functional, and subject to possible Coulomb corrections, it is possible to construct isoscalar and isovector densities out of the proton and neutron densities, that retain a universal relation to each other, approximately independent of asymmetry. In the so-called local approximation, the isovector density is inversely proportional to the symmetry energy in uniform matter at the local isoscalar density. Generalized symmetry coefficient of a nuclear system is related, in the analytic limit of a functional, to an integral of the isovector density. We test the relations, inferred from the Hohenberg-Kohn functional, in the Skyrme-Hartree-Fock calculations of half-infinite matter. Within the calculations, we obtain surface symmetry coefficients and parameters characterizing the densities, for the majority of Skyrme parameterizations proposed in the literature. The volume-to-surface symmetry-coefficient ratio and the displacement of nuclear isovector relative to isoscalar surfaces both strongly increase as the slope of symmetry energy in the vicinity of normal density increases.

Pawel Danielewicz; Jenny Lee

2008-07-23T23:59:59.000Z

298

Universal symmetry-protected topological invariants for symmetry-protected topological states  

E-Print Network [OSTI]

Symmetry-protected topological (SPT) states are short-range entangled states with a symmetry G. They belong to a new class of quantum states of matter which are classified by the group cohomology $H^{d+1}(G,\\mathbb{R}/\\mathbb{Z})$ in d-dimensional space. In this paper, we propose a class of symmetry- protected topological invariants that may allow us to fully characterize SPT states with a symmetry group G (ie allow us to measure the cocycles in $H^{d+1}(G,\\mathbb{R}/\\mathbb{Z})$ that characterize the SPT states). We give an explicit and detailed construction of symmetry-protected topological invariants for 2+1D SPT states. Such a construction can be directly generalized to other dimensions.

Hung, Ling-Yan

2013-01-01T23:59:59.000Z

299

Symmetry Energy II: Isobaric Analog States  

E-Print Network [OSTI]

Using excitation energies to isobaric analog states (IAS) and charge invariance, we extract nuclear symmetry coefficients, from a mass formula, on a nucleus-by-nucleus basis. Consistently with charge invariance, the coefficients vary weakly across an isobaric chain. However, they change strongly with nuclear mass and range from a_a~10 MeV at mass A~10 to a_a~22 MeV at A~240. Following the considerations of a Hohenberg-Kohn functional for nuclear systems, we determine how to find in practice the symmetry coefficient using neutron and proton densities, even when those densities are simultaneously affected by significant symmetry-energy and Coulomb effects. These results facilitate extracting the symmetry coefficients from Skyrme-Hartree-Fock (SHF) calculations, that we carry out using a variety of Skyrme parametrizations in the literature. For the parametrizations, we catalog novel short-wavelength instabilities. In comparing the SHF and IAS results for the symmetry coefficients, we arrive at narrow (+-2.4 MeV)...

Danielewicz, Pawel

2014-01-01T23:59:59.000Z

300

Symmetry Energy I: Semi-Infinite Matter  

E-Print Network [OSTI]

Nuclear energy is considered in the macroscopic limit for a nucleus. Considered, further, is the Hohenberg-Kohn functional for a nuclear system, in terms of proton and neutron densities. Finally, Skyrme-Hartree-Fock calculations are carried out for half-infinite particle-stable nuclear matter. In each case, the attention is focused on the role of neutron-proton asymmetry and on the symmetry energy. We extend the considerations on the symmetry term from an energy formula to the respective term in the Hohenberg-Kohn functional. We show, in particular, that in continuum limit of the considered functional, and subject to possible Coulomb corrections, it is possible to construct isoscalar and isovector densities out of the proton and neutron densities, that retain a universal relation to each other, approximately independent of asymmetry. In the so-called local approximation, the isovector density is inversely proportional to the symmetry energy in uniform matter at the local isoscalar density. Generalized symmetr...

Danielewicz, Pawel

2008-01-01T23:59:59.000Z

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


301

Symmetry Energy II: Isobaric Analog States  

E-Print Network [OSTI]

Using excitation energies to isobaric analog states (IAS) and charge invariance, we extract nuclear symmetry coefficients, from a mass formula, on a nucleus-by-nucleus basis. Consistently with charge invariance, the coefficients vary weakly across an isobaric chain. However, they change strongly with nuclear mass and range from a_a~10 MeV at mass A~10 to a_a~22 MeV at A~240. Following the considerations of a Hohenberg-Kohn functional for nuclear systems, we determine how to find in practice the symmetry coefficient using neutron and proton densities, even when those densities are simultaneously affected by significant symmetry-energy and Coulomb effects. These results facilitate extracting the symmetry coefficients from Skyrme-Hartree-Fock (SHF) calculations, that we carry out using a variety of Skyrme parametrizations in the literature. For the parametrizations, we catalog novel short-wavelength instabilities. In comparing the SHF and IAS results for the symmetry coefficients, we arrive at narrow (+-2.4 MeV) constraints on the symmetry energy values S(rho) at 0.04

Pawel Danielewicz; Jenny Lee

2013-07-15T23:59:59.000Z

302

Compartmentalization analysis using discrete fracture network models  

SciTech Connect (OSTI)

This paper illustrates how Discrete Fracture Network (DFN) technology can serve as a basis for the calculation of reservoir engineering parameters for the development of fractured reservoirs. It describes the development of quantitative techniques for defining the geometry and volume of structurally controlled compartments. These techniques are based on a combination of stochastic geometry, computational geometry, and graph theory. The parameters addressed are compartment size, matrix block size and tributary drainage volume. The concept of DFN models is explained and methodologies to compute these parameters are demonstrated.

La Pointe, P.R.; Eiben, T.; Dershowitz, W. [Golder Associates Inc., Redmond, WA (United States); Wadleigh, E. [Marathon Oil Company, Midland, TX (United States). Mid-Continent Region Production

1997-12-31T23:59:59.000Z

303

Compartmentalization analysis using discrete fracture network models  

SciTech Connect (OSTI)

This paper illustrates how Discrete Fracture Network (DFN) technology can serve as a basis for the calculation of reservoir engineering parameters for the development of fractured reservoirs. It describes the development of quantitative techniques for defining the geometry and volume of structurally controlled compartments. These techniques are based on a combination of stochastic geometry, computational geometry, and graph the theory. The parameters addressed are compartment size, matrix block size and tributary drainage volume. The concept of DFN models is explained and methodologies to compute these parameters are demonstrated.

La Pointe, P.R.; Eiben, T.; Dershowitz, W. [Golder Associates, Redmond, VA (United States); Wadleigh, E. [Marathon Oil Co., Midland, TX (United States)

1997-08-01T23:59:59.000Z

304

Robustness of discrete-time control systems  

E-Print Network [OSTI]

. The Bilinear Approach s-Plane to z-Plane F. Overbounding and Testing for Stability G. Interlacing Properties of Interval Polynomials Interlacing Property for Continuous- Time Systems Interlacing Property for Discrete- Time Systems Page 26 27 29 33... of p(z) from F(+t) Calculation of s+q Calculation of s~i Calculation of the Minimum Distance of p(z) from P&? Calculation of s Calculation of s Calculation of the Minimum Distance of p(z) from Flsi Calculation of ss Calculation of ss E...

Aguirre, Gabriel

1989-01-01T23:59:59.000Z

305

Modified discrete random walk with absorption  

E-Print Network [OSTI]

We obtain expected number of arrivals, probability of arrival, absorption probabilities and expected time before absorption for a modified discrete random walk on the (sub)set of integers. In a [pqrs] random walk the particle can move one step forward or backward, stay for a moment in the same state or it can be absorbed immediately in the current state. M[pqrs] is a modified version, where probabilities on both sides of a multiple function barrier M are of different [pqrs] type.

Theo van Uem

2009-03-02T23:59:59.000Z

306

Black Hole Thermodynamics and Lorentz Symmetry  

E-Print Network [OSTI]

Recent developments point to a breakdown in the generalized second law of thermodynamics for theories with Lorentz symmetry violation. It appears possible to construct a perpetual motion machine of the second kind in such theories, using a black hole to catalyze the conversion of heat to work. Here we describe and extend the arguments leading to that conclusion. We suggest the inference that local Lorentz symmetry may be an emergent property of the macroscopic world with origins in a microscopic second law of causal horizon thermodynamics.

Ted Jacobson; Aron C. Wall

2010-02-04T23:59:59.000Z

307

Chimera Death: Symmetry Breaking in Dynamical Networks  

E-Print Network [OSTI]

For a network of generic oscillators with nonlocal topology and symmetry-breaking coupling we establish novel partially coherent inhomogeneous spatial patterns, which combine the features of chimera states (coexisting incongruous coherent and incoherent domains) and oscillation death (oscillation suppression), which we call chimera death. We show that due to the interplay of nonlocality and breaking of rotational symmetry by the coupling two distinct scenarios from oscillatory behavior to a stationary state regime are possible: a transition from an amplitude chimera to chimera death via in-phase synchronized oscillations, and a direct abrupt transition for larger coupling strength.

Anna Zakharova; Marie Kapeller; Eckehard Schöll

2014-02-03T23:59:59.000Z

308

Holographic Metals and Insulators with Helical Symmetry  

E-Print Network [OSTI]

Homogeneous, zero temperature scaling solutions with Bianchi VII spatial geometry are constructed in Einstein-Maxwell-Dilaton theory. They correspond to quantum critical saddle points with helical symmetry at finite density. Assuming $AdS_{5}$ UV asymptotics, the small frequency/(temperature) dependence of the AC/(DC) electric conductivity along the director of the helix are computed. A large class of insulating and conducting anisotropic phases is found, as well as isotropic, metallic phases. Conduction can be dominated by dissipation due to weak breaking of translation symmetry or by a quantum critical current.

Aristomenis Donos; Blaise Goutéraux; Elias Kiritsis

2014-09-17T23:59:59.000Z

309

Symmetries and "principles of construction" in Foundations  

E-Print Network [OSTI]

Symmetries and "principles of construction" in Foundations Giuseppe Longo LIENS, CNRS ­ ENS, Paris Preliminaries A "foundational analysis" (a fully justified search for "unshakable certainties", in 1900) Frege and Hilbert: the search for (proof) principles and "unshakable certainties" (different: absolute laws

Longo, Giuseppe

310

Evidential Symmetry and Mushy Credence Roger White  

E-Print Network [OSTI]

1 Evidential Symmetry and Mushy Credence Roger White MIT rog@mit.edu draft 4/07 The Principle arise. I'm wondering if the marble taken from this urn is black or white. I might have a rich body in the box has been selected from a shaken urn containing just five white and five black balls. Or I might

Fitelson, Branden

311

Weyl-Gauge Symmetry of Graphene  

E-Print Network [OSTI]

The conformal invariance of the low energy limit theory governing the electronic properties of graphene is explored. In particular, it is noted that the massless Dirac theory in point enjoys local Weyl symmetry, a very large symmetry. Exploiting this symmetry in the two spatial dimensions and in the associated three dimensional spacetime, we find the geometric constraints that correspond to specific shapes of the graphene sheet for which the electronic density of states is the same as that for planar graphene, provided the measurements are made in accordance to the inner reference frame of the electronic system. These results rely on the (surprising) general relativistic-like behavior of the graphene system arising from the combination of its well known special relativistic-like behavior with the less explored Weyl symmetry. Mathematical structures, such as the Virasoro algebra and the Liouville equation, naturally arise in this three-dimensional context and can be related to specific profiles of the graphene sheet. Speculations on possible applications of three-dimensional gravity are also proposed.

Alfredo Iorio

2011-01-19T23:59:59.000Z

312

analyzing incomplete discrete: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Geometric Approach to ML Estimation With Incomplete Data: Application to Semi Reilly, James P. 94 Energy Levels of "Hydrogen Atom" in Discrete Time Dynamics Quantum Physics...

313

A quantitative description of mesh dependence for the discretization ...  

E-Print Network [OSTI]

that coming from a ferromagnetic spin energy. The critical case can be regarded as an interpolation between the two. Key words. spatial discretization, singularly

2012-07-09T23:59:59.000Z

314

Efficient energy stable schemes with spectral discretization in space ...  

E-Print Network [OSTI]

We construct energy stable schemes for the time discretization of the highly nonlinear ... shape) in order to achieve a well-defined energy for the system.

2012-04-03T23:59:59.000Z

315

2-D discrete element modeling of unconsolidated sandstones.  

E-Print Network [OSTI]

??In this work unconsolidated sands saturated with heavy oil were modeled using a discrete element numerical model, (DEM). The DEM code was built in Mathematica… (more)

Franquet Barbara, Javier Alejandro

2012-01-01T23:59:59.000Z

316

attila discrete ordinance: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

recurrence satisfied by the Stirling numbers of the second kind. Abrams, Aaron; Hower, Valerie 2010-01-01 428 VARIATIONAL ESTIMATES FOR DISCRETE SCHR Mathematics Websites...

317

attila discrete ordinates: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

recurrence satisfied by the Stirling numbers of the second kind. Abrams, Aaron; Hower, Valerie 2010-01-01 428 VARIATIONAL ESTIMATES FOR DISCRETE SCHR Mathematics Websites...

318

optimization of discrete control systems with varying structure  

E-Print Network [OSTI]

(in russian). 4. Mansimov, K.B., Maharramov, Sh.F.: Necessary conditions of optimality for discrete system with variable structure and rolling right end of the path.

xx

2004-12-16T23:59:59.000Z

319

The robust stabilization problem for discrete-time descriptor systems  

E-Print Network [OSTI]

Sep 23, 2014 ... Abstract: We investigate the robust stabilization problem for the descriptor discrete-time systems and build an optimal solution in the case when ...

Claudiu Dinicu

2014-09-23T23:59:59.000Z

320

Group Momentum Space and Hopf Algebra Symmetries of Point Particles Coupled to 2+1 Gravity  

E-Print Network [OSTI]

We present an in-depth investigation of the ${\\rm SL}(2,\\mathbb{R})$ 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 ${\\rm SL}(2,\\mathbb{R})$. 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.

Michele Arzano; Danilo Latini; Matteo Lotito

2014-07-24T23:59:59.000Z

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


321

Gapped symmetry preserving surface state for the electron topological insulator  

E-Print Network [OSTI]

It is well known that the three-dimensional (3D) electronic topological insulator (TI) with charge-conservation and time-reversal symmetry cannot have a trivial insulating surface that preserves symmetry. It is often ...

Wang, Chong

322

Statistical Behavior and Symmetry Tests G. E. Mitchell  

E-Print Network [OSTI]

Statistical Behavior and Symmetry Tests G. E. Mitchell North Carolina State University, Raleigh, NC Technological University, Cookeville, TN 38505 (Dated: April 12, 2004) Symmetries and statistical properties violation in neutron resonances. Statistical distribu- tions can provide information about the underlying

Shriner, John

323

Synchronous Symmetry Breaking in Neurons with Different Neurite Counts  

E-Print Network [OSTI]

As neurons develop, several immature processes (i.e., neurites) grow out of the cell body. Over time, each neuron breaks symmetry when only one of its neurites grows much longer than the rest, becoming an axon. This symmetry ...

Wissner-Gross, Zachary D.

324

Sets of Symmetry Breaking Constraints Barbara M. Smith  

E-Print Network [OSTI]

Sets of Symmetry Breaking Constraints Barbara M. Smith Cork Constraint Computation Centre, University College Cork, Ireland b.m.smith@4c.ucc.ie Abstract [Puget, 2004] has shown that if the symmetry

Smith, Barbara M.

325

On Symmetry, Perspectivity, and Level-Set-Based Segmentation  

E-Print Network [OSTI]

We introduce a novel variational method for the extraction of objects with either bilateral or rotational symmetry in the presence of perspective distortion. Information on the symmetry axis of the object and the distorting ...

Riklin-Raviv, Tammy

326

Order statistics inference for describing topological coupling and mechanical symmetry breaking in multidomain proteins  

E-Print Network [OSTI]

Cooperativity is a hallmark of proteins, many of which show a modular architecture comprising discrete structural domains. Detecting and describing dynamic couplings between structural regions is difficult in view of the many-body nature of protein-protein interactions. By utilizing the GPU-based computational acceleration, we carried out simulations of the protein forced unfolding for the dimer WW-WW of the all-beta-sheet WW domains used as a model multidomain protein. We found that while the physically non-interacting identical protein domains (WW) show nearly symmetric mechanical properties at low tension, reflected, e.g., in the similarity of their distributions of unfolding times, these properties become distinctly different when tension is increased. Moreover, the uncorrelated unfolding transitions at a low pulling force become increasingly more correlated (dependent) at higher forces. Hence, the applied force not only breaks "the mechanical symmetry" but also couples the physically non-interacting prot...

Kononova, Olga; Barsegov, Valeri

2015-01-01T23:59:59.000Z

327

Relativistic U(3) symmetry and pseudo-U(3) symmetry of the Dirac Hamiltonian  

SciTech Connect (OSTI)

The Dirac Hamiltonian with relativistic scalar and vector harmonic oscillator potentials has been solved analytically in two limits. One is the spin limit for which spin is an invariant symmetry of the the Dirac Hamiltonian and the other is the pseudo-spin limit for which pseudo-spin is an invariant symmetry of the Dirac Hamiltonian. The spin limit occurs when the scalar potential is equal to the vector potential plus a constant, and the pseudospin limit occurs when the scalar potential is equal in magnitude but opposite in sign to the vector potential plus a constant. Like the non-relativistic harmonic oscillator, each of these limits has a higher symmetry. For example, for the spherically symmetric oscillator, these limits have a U(3) and pseudo-U(3) symmetry respectively. We shall discuss the eigenfunctions and eigenvalues of these two limits and derive the relativistic generators for the U(3) and pseudo-U(3) symmetry. We also argue, that, if an anti-nucleon can be bound in a nucleus, the spectrum will have approximate spin and U(3) symmetry.

Ginocchio, Joseph N [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

328

Nuclear symmetry energy at subnormal densities from measured nuclear masses  

E-Print Network [OSTI]

The symmetry energy coefficients for nuclei with mass number A=20~250 are extracted from more than 2000 measured nuclear masses. With the semi-empirical connection between the symmetry energy coefficients of finite nuclei and the nuclear symmetry energy at reference densities, we investigate the density dependence of symmetry energy of nuclear matter at subnormal densities. The obtained results are compared with those extracted from other methods.

Min Liu; Ning Wang; Zhuxia Li; Fengshou Zhang

2010-11-17T23:59:59.000Z

329

Discovering the New Standard Model: Fundamental Symmetries and Neutrinos  

E-Print Network [OSTI]

This White Paper describes recent progress and future opportunities in the area of fundamental symmetries and neutrinos.

V. Cianciolo; A. B. Balantekin; A. Bernstein; V. Cirigliano; M. D. Cooper; D. J. Dean; S. R. Elliott; B. W. Filippone; S. J. Freedman; G. L. Greene; K. M. Heeger; D. W. Hertzog; B. R. Holstein; P. Huffman; T. Ito; K. Kumar; Z. -T. Lu; J. S. Nico; G. D. Orebi Gann; K. Paschke; A. Piepke; B. Plaster; D. Pocanic; A. W. P. Poon; D. C. Radford; M. J. Ramsey-Musolf; R. G. H. Robertson; G. Savard; K. Scholberg; Y. Semertzidis; J. F. Wilkerson

2012-12-20T23:59:59.000Z

330

Discovering the New Standard Model: Fundamental Symmetries and Neutrinos  

E-Print Network [OSTI]

This White Paper describes recent progress and future opportunities in the area of fundamental symmetries and neutrinos.

Cianciolo, V; Bernstein, A; Cirigliano, V; Cooper, M D; Dean, D J; Elliott, S R; Filippone, B W; Freedman, S J; Greene, G L; Heeger, K M; Hertzog, D W; Holstein, B R; Huffman, P; Ito, T; Kumar, K; Lu, Z -T; Nico, J S; Gann, G D Orebi; Paschke, K; Piepke, A; Plaster, B; Pocanic, D; Poon, A W P; Radford, D C; Ramsey-Musolf, M J; Robertson, R G H; Savard, G; Scholberg, K; Semertzidis, Y; Wilkerson, J F

2012-01-01T23:59:59.000Z

331

SO(4) symmetry in the relativistic hydrogen atom  

E-Print Network [OSTI]

We show that the relativistic hydrogen atom possesses an SO(4) symmetry by introducing a kind of pseudo-spin vector operator. The same SO(4) symmetry is still preserved in the relativistic quantum system in presence of an U(1) monopolar vector potential as well as a nonabelian vector potential. Lamb shift and SO(4) symmetry breaking are also discussed.

Jing-Ling Chen; Dong-Ling Deng; Ming-Guang Hu

2008-05-08T23:59:59.000Z

332

SHAPE MATCHING USING FUZZY DISCRETE PARTICLE SWARM OPTIMIZATION*  

E-Print Network [OSTI]

importantly, the recognition based on shape feature is also a central problem in those fields such as patternSHAPE MATCHING USING FUZZY DISCRETE PARTICLE SWARM OPTIMIZATION* Ji-Xiang Du1, 2 De-Shuang Huang1 based on fuzzy discrete particle swarm optimization (FDPSO) is proposed. Based on fuzzy theory and PSO

Hefei Institute of Intelligent Machines

333

Combined Delta-Nabla Sum Operator in Discrete Fractional Calculus  

E-Print Network [OSTI]

We introduce a more general discrete fractional operator, given by convex linear combination of the delta and nabla fractional sums. Fundamental properties of the new fractional operator are proved. As particular cases, results on delta and nabla discrete fractional calculus are obtained.

Bastos, Nuno R O

2010-01-01T23:59:59.000Z

334

University of Michigan and NBER "Identification of Discrete Choice  

E-Print Network [OSTI]

Presenter: Jeremy Fox University of Michigan and NBER "Identification of Discrete Choice Models;Identification of Discrete Choice Models for Bundles and Binary Games Jeremy T. Fox University of Michigan and NBER Natalia Lazzati University of Michigan March 2014 Abstract We study nonparametric identification

335

Cryptanalysing the Critical Group: Efficiently Solving Biggs's Discrete Logarithm Problem  

E-Print Network [OSTI]

Cryptanalysing the Critical Group: Efficiently Solving Biggs's Discrete Logarithm Problem Simon R Kingdom s.blackburn@rhul.ac.uk November 7, 2008 Abstract Biggs has recently proposed the critical group that the discrete log problem can be efficiently solved in Biggs's groups. Thus this class of groups is not suitable

336

Mechanical Integrators Derived from a Discrete Variational Principle  

E-Print Network [OSTI]

Mechanical Integrators Derived from a Discrete Variational Principle Jerey M. Wendlandt1;2 Mechanical Engineering, University of California at Berkeley, Berkeley, CA 94720, USA Jerrold E. Marsden3 for mechanical system simulation are created by using discrete algorithms to approximate the continuous equations

Marsden, Jerrold

337

XXZ scalar products, Miwa variables and discrete KP  

E-Print Network [OSTI]

We revisit the quantum/classical integrable model correspondence in the context of inhomogeneous finite length XXZ spin-1/2 chains with periodic boundary conditions and show that the Bethe scalar product of an arbitrary state and a Bethe eigenstate is a discrete KP tau-function. The continuous Miwa variables of discrete KP are the rapidities of the arbitrary state.

O. Foda; G. Schrader

2010-05-21T23:59:59.000Z

338

Video Denoising and Simplification Via Discrete Regularization on Graphs  

E-Print Network [OSTI]

Video Denoising and Simplification Via Discrete Regularization on Graphs Mahmoud Ghoniem, Youssef algorithms for video de- noising and simplification based on discrete regularization on graphs. The main difference between video and image denoising is the temporal redundancy in video sequences. Recent works

Paris-Sud XI, Université de

339

Generalized gravitational entropy without replica symmetry  

E-Print Network [OSTI]

We explore several extensions of the generalized entropy construction of Lewkowycz and Maldacena, including a formulation that does not rely on preserving replica symmetry in the bulk. We show that an appropriately general ansatz for the analytically continued replica metric gives us the flexibility needed to solve the gravitational field equations beyond general relativity. As an application of this observation we study Einstein-Gauss-Bonnet gravity with a small Gauss-Bonnet coupling and derive the condition that the holographic entanglement entropy must be evaluated on a surface which extremizes the Jacobson-Myers entropy. We find that in both general relativity and Einstein-Gauss-Bonnet gravity replica symmetry breaking terms are permitted by the field equations, suggesting that they do not generically vanish.

Joan Camps; William R. Kelly

2015-01-13T23:59:59.000Z

340

Generalized harmonic formulation in spherical symmetry  

E-Print Network [OSTI]

In this pedagogically structured article, we describe a generalized harmonic formulation of the Einstein equations in spherical symmetry which is regular at the origin. The generalized harmonic approach has attracted significant attention in numerical relativity over the past few years, especially as applied to the problem of binary inspiral and merger. A key issue when using the technique is the choice of the gauge source functions, and recent work has provided several prescriptions for gauge drivers designed to evolve these functions in a controlled way. We numerically investigate the parameter spaces of some of these drivers in the context of fully non-linear collapse of a real, massless scalar field, and determine nearly optimal parameter settings for specific situations. Surprisingly, we find that many of the drivers that perform well in 3+1 calculations that use Cartesian coordinates, are considerably less effective in spherical symmetry, where some of them are, in fact, unstable.

Evgeny Sorkin; Matthew W. Choptuik

2010-04-30T23:59:59.000Z

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


341

Mirror Symmetry in Physics: The Basics  

E-Print Network [OSTI]

These notes are aimed at mathematicians working on topics related to mirror symmetry, but are unfamiliar with the physical origins of this subject. We explain the physical concepts that enable this surprising duality to exist, using the torus as an illustrative example. Then, we develop the basic foundations of conformal field theory so that we can explain how mirror symmetry was first discovered in that context. Along the way we will uncover a deep connection between conformal field theories with (2,2) supersymmetry and Calabi-Yau manifolds. (Based on lectures given during the "Thematic Program on Calabi-Yau Varieties: Arithmetic, Geometry and Physics" at the Fields Institute in Toronto, October 10-11, 2013.)

Callum Quigley

2014-12-28T23:59:59.000Z

342

Constraining the nuclear symmetry-energy at super-density  

E-Print Network [OSTI]

The nuclear symmetry-energy has broad implications in both nuclear physics and astrophysics. Due to hard work of many people, the nuclear symmetry-energy around saturation density has been roughly constrained. However, the nuclear symmetry-energy at super-density is still in chaos. By considering both the effects of the nucleon-nucleon short-rang correlations and the isospin-dependent in-medium inelastic baryon-baryon scattering cross sections in the transport model, two unrelated experimental measurements are simultaneously analyzed. A soft symmetry-energy at super-density is first consistently obtained by the double comparison of the symmetry-energy sensitive observables.

Yong, Gao-Chan

2015-01-01T23:59:59.000Z

343

FLUID BIAXIAL BANANA PHASES: SYMMETRY AT WORK  

E-Print Network [OSTI]

FLUID BIAXIAL BANANA PHASES: SYMMETRY AT WORK P. E. Cladis,1 Helmut R. Brand2 and Harald Pleiner3 1. The macro- #12;P. E. Cladis, H. R. Brand and H. Pleiner Page 2 of 10 10/13/99 8:12 AM scopic expression a right-handed helix, then, -qo describes a left-handed one. As the mirror image of a right-hand is a left

Cladis, Patricia E.

344

Ermakov-Lewis symmetry in photonic lattices  

E-Print Network [OSTI]

We present a class of waveguide arrays that is the classical analog of a quantum harmonic oscillator where the mass and frequency depend on the propagation distance. In these photonic lattices refractive indices and second neighbor couplings define the mass and frequency of the analog quantum oscillator, while first neighbor couplings are a free parameter to adjust the model. The quantum model conserves the Ermakov-Lewis invariant, thus the photonic crystal also posses this symmetry.

Lara, B M Rodríguez; Moya-Cessa, H M; Christodoulides, D N

2014-01-01T23:59:59.000Z

345

Radiatively broken symmetries of nonhierarchical neutrinos  

E-Print Network [OSTI]

Symmetry-based ideas, such as the quark-lepton complementarity (QLC) principle and the tri-bimaximal mixing (TBM) scheme, have been proposed to explain the observed mixing pattern of neutrinos. We argue that such symmetry relations need to be imposed at a high scale $\\Lambda \\sim 10^{12}$ GeV characterizing the large masses of right-handed neutrinos required to implement the seesaw mechanism. For nonhierarchical neutrinos, renormalisation group evolution down to a laboratory energy scale $\\lambda \\sim 10^3$ GeV tends to radiatively break these symmetries at a significant level and spoil the mixing pattern predicted by them. However, for Majorana neutrinos, suitable constraints on the extra phases $\\alpha_{2,3}$ enable the retention of those high scale mixing patterns at laboratory energies. We examine this issue within the Minimal Supersymmetric Standard Model (MSSM) and demonstrate the fact posited above for two versions of QLC and two versions of TBM. The appropriate constraints are worked out for all these...

Dighe, Amol; Roy, Probir

2007-01-01T23:59:59.000Z

346

Symmetry and Evolution in Quantum Gravity  

E-Print Network [OSTI]

We propose an operator constraint equation for the wavefunction of the Universe that admits genuine evolution. While the corresponding classical theory is equivalent to the canonical decomposition of General Relativity, the quantum theory makes predictions that are distinct from Wheeler-DeWitt cosmology. Furthermore, the local symmetry principle - and corresponding observables - of the theory have a direct interpretation in terms of a conventional gauge theory, where the gauge symmetry group is that of spatial conformal diffeomorphisms (that preserve the spatial volume of the Universe). The global evolution is in terms of an arbitrary parameter that serves only as an unobservable label for successive states of the Universe. Our proposal follows unambiguously from a suggestion of York whereby the independently specifiable initial data in the action principle of General Relativity is given by a conformal geometry and the spatial average of the York time on the spacelike hypersurfaces that bound the variation. Remarkably, such a variational principle uniquely selects the form of the constraints of the theory so that we can establish a precise notion of both symmetry and evolution in quantum gravity.

Sean Gryb; Karim Thebault

2014-03-25T23:59:59.000Z

347

Exploring Cartan gravity with dynamical symmetry breaking  

E-Print Network [OSTI]

It has been known for some time that General Relativity can be regarded as a Yang-Mills-type gauge theory in a symmetry broken phase. In this picture the gravity sector is described by an $SO(1,4)$ or $SO(2,3)$ gauge field $A^{a}_{\\phantom{a}b\\mu}$ and Higgs field $V^{a}$ which acts to break the symmetry down to that of the Lorentz group $SO(1,3)$. This symmetry breaking mirrors that of electroweak theory. However, a notable difference is that while the Higgs field $\\Phi$ of electroweak theory is taken as a genuine dynamical field satisfying a Klein-Gordon equation, the gauge independent norm $V^2\\equiv \\eta_{ab}V^{a}V^{b}$ of the Higgs-type field $V^a$ is typically regarded as non-dynamical. Instead, in many treatments $V^a$ does not appear explicitly in the formalism or is required to satisfy $V^2 = \\mathrm{const.} \

H. F. Westman; T. G. Zlosnik

2014-03-24T23:59:59.000Z

348

Maxwell Equations in Complex Form of Majorana - Oppenheimer, Solutions with Cylindric Symmetry in Riemann S_{3} and Lobachevsky H_{3} Spaces  

E-Print Network [OSTI]

Complex formalism of Riemann - Silberstein - Majorana - Oppenheimer in Maxwell electrodynamics is extended to the case of arbitrary pseudo-Riemannian space - time in accordance with the tetrad recipe of Tetrode - Weyl - Fock - Ivanenko. In this approach, the Maxwell equations are solved exactly on the background of static cosmological Einstein model, parameterized by special cylindrical coordinates and realized as a Riemann space of constant positive curvature. A discrete frequency spectrum for electromagnetic modes depending on the curvature radius of space and three parameters is found, and corresponding basis electromagnetic solutions have been constructed explicitly. In the case of elliptical model a part of the constructed solutions should be rejected by continuity considerations. Similar treatment is given for Maxwell equations in hyperbolic Lobachevsky model, the complete basis of electromagnetic solutions in corresponding cylindrical coordinates has been constructed as well, no quantization of frequencies of electromagnetic modes arises.

A. A. Bogush; G. G. Krylov; E. M. Ovsiyuk; V. M. Red'kov

2009-07-05T23:59:59.000Z

349

Discrete Exterior Geometry Approach to Structure-Preserving Discretization of Distributed-Parameter Port-Hamiltonian Systems  

E-Print Network [OSTI]

This paper addresses the issue of structure-preserving discretization of open distributed-parameter systems with Hamiltonian dynamics. Employing the formalism of discrete exterior calculus, we introduce a simplicial Dirac structure as a discrete analogue of the Stokes-Dirac structure and demonstrate that it provides a natural framework for deriving finite-dimensional port-Hamiltonian systems that emulate their infinite-dimensional counterparts. The spatial domain, in the continuous theory represented by a finite-dimensional smooth manifold with boundary, is replaced by a homological manifold-like simplicial complex and its augmented circumcentric dual. The smooth differential forms, in discrete setting, are mirrored by cochains on the primal and dual complexes, while the discrete exterior derivative is defined to be the coboundary operator. This approach of discrete differential geometry, rather than discretizing the partial differential equations, allows to first discretize the underlying Stokes-Dirac structure and then to impose the corresponding finite-dimensional port-Hamiltonian dynamics. In this manner, a number of important intrinsically topological and geometrical properties of the system are preserved.

Marko Seslija; Arjan van der Schaft; Jacquelien M. A. Scherpen

2012-02-27T23:59:59.000Z

350

Classifying symmetry-protected topological phases through the anomalous action of the symmetry on the edge  

E-Print Network [OSTI]

It is well known that (1+1)-D bosonic symmetry-protected topological (SPT) phases with symmetry group $G$ can be identified by the projective representation of the symmetry at the edge. Here, we generalize this result to higher dimensions. We assume that the representation of the symmetry on the spatial edge of a ($d+1$)-D SPT is /local/ but not necessarily /on-site/, such that there is an obstruction to its implementation on a region with boundary. We show that such obstructions are classified by the cohomology group $H^{d+1}(G, U(1))$, in agreement with the classification of bosonic SPT phases proposed in [Chen et al, Science 338, 1604 (2012)]. Our analysis allows for a straightforward calculation of the element of $H^{d+1}(G, U(1))$ corresponding to physically meaningful models such as non-linear sigma models with a theta term in the action. SPT phases outside the classification of Chen et al are those in which the symmetry cannot be represented locally on the edge. With some modifications, our framework can also be applied to fermionic systems in (2+1)-D.

Dominic V. Else; Chetan Nayak

2015-01-09T23:59:59.000Z

351

Information storage capacity of discrete spin systems  

SciTech Connect (OSTI)

Understanding the limits imposed on information storage capacity of physical systems is a problem of fundamental and practical importance which bridges physics and information science. There is a well-known upper bound on the amount of information that can be stored reliably in a given volume of discrete spin systems which are supported by gapped local Hamiltonians. However, all the previously known systems were far below this theoretical bound, and it remained open whether there exists a gapped spin system that saturates this bound. Here, we present a construction of spin systems which saturate this theoretical limit asymptotically by borrowing an idea from fractal properties arising in the Sierpinski triangle. Our construction provides not only the best classical error-correcting code which is physically realizable as the energy ground space of gapped frustration-free Hamiltonians, but also a new research avenue for correlated spin phases with fractal spin configurations. -- Highlights: •We propose a spin model with fractal ground states and study its coding properties. •We show that the model asymptotically saturates a theoretical limit on information storage capacity. •We discuss its relations to various theoretical physics problems.

Yoshida, Beni, E-mail: rouge@caltech.edu

2013-11-15T23:59:59.000Z

352

Multidimensional electron-photon transport with standard discrete ordinates codes  

SciTech Connect (OSTI)

A method is described for generating electron cross sections that are compatible with standard discrete ordinates codes without modification. There are many advantages of using an established discrete ordinates solver, e.g. immediately available adjoint capability. Coupled electron-photon transport capability is needed for many applications, including the modeling of the response of electronics components to space and man-made radiation environments. The cross sections have been successfully used in the DORT, TWODANT and TORT discrete ordinates codes. The cross sections are shown to provide accurate and efficient solutions to certain multidimensional electronphoton transport problems.

Drumm, C.R.

1995-12-31T23:59:59.000Z

353

Space Time Quantization and the Big Bang  

E-Print Network [OSTI]

A recent cosmological model is recapitulated which deduces the correct mass, radius and age of the universe as also the Hubble constant and other well known apparently coincidental relations. It also predicts an ever expanding accelerating universe as is confirmed by latest supernovae observations. Finally the Big Bang model is recovered as a suitable limiting case.

B. G. Sidharth

1998-06-21T23:59:59.000Z

354

On the warp drive space-time  

E-Print Network [OSTI]

In this paper the problem of the quantum stability of the two-dimensional warp drive spacetime moving with an apparent faster than light velocity is considered. We regard as a maximum extension beyond the event horizon of that spacetime its embedding in a three-dimensional Minkowskian space with the topology of the corresponding Misner space. It is obtained that the interior of the spaceship bubble becomes then a multiply connected nonchronal region with closed timelike curves and that the most natural vacuum allows quantum fluctuations which do not induce any divergent behaviour of the re-normalized stress-energy tensor, even on the event (Cauchy) chronology horizon. In such a case, the horizon encloses closed timelike curves only at scales close to the Planck length, so that the warp drive satisfies the Ford's negative energy-time inequality. Also found is a connection between the superluminal two-dimensional warp drive space and two-dimensional gravitational kinks. This connection allows us to generalize the considered Alcubierre metric to a standard, nonstatic metric which is only describable on two different coordinate patches

Pedro F. Gonzalez-Diaz

2000-04-10T23:59:59.000Z

355

Synthetic morphogenesis : space, time, and deformation  

E-Print Network [OSTI]

Synthetic biology has presented engineers with a fascinating opportunity: can we understand the principles of our origins { animal embryonic development - by re-engineering it in the laboratory? I investigate, from an ...

Brodsky, Micah Z. (Micah Zev)

2014-01-01T23:59:59.000Z

356

Twisted supersymmetry: Twisted symmetry versus renormalizability  

SciTech Connect (OSTI)

We discuss a deformation of superspace based on a Hermitian twist. The twist implies a *-product that is noncommutative, Hermitian and finite when expanded in a power series of the deformation parameter. The Leibniz rule for the twisted supersymmetry transformations is deformed. A minimal deformation of the Wess-Zumino action is proposed and its renormalizability properties are discussed. There is no tadpole contribution, but the two-point function diverges. We speculate that the deformed Leibniz rule, or more generally the twisted symmetry, interferes with renormalizability properties of the model. We discuss different possibilities to render a renormalizable model.

Dimitrijevic, Marija; Nikolic, Biljana; Radovanovic, Voja [Faculty of Physics, University of Belgrade, Studentski Trg 12, 11000 Beograd (Serbia)

2011-03-15T23:59:59.000Z

357

Harmonic pinnacles in the Discrete Gaussian model  

E-Print Network [OSTI]

The 2D Discrete Gaussian model gives each height function $\\eta : \\mathbb{Z}^2\\to\\mathbb{Z}$ a probability proportional to $\\exp(-\\beta \\mathcal{H}(\\eta))$, where $\\beta$ is the inverse-temperature and $\\mathcal{H}(\\eta) = \\sum_{x\\sim y}(\\eta_x-\\eta_y)^2$ sums over nearest-neighbor bonds. We consider the model at large fixed $\\beta$, where it is flat unlike its continuous analog (the Gaussian Free Field). We first establish that the maximum height in an $L\\times L$ box with 0 boundary conditions concentrates on two integers $M,M+1$ with $M\\sim \\sqrt{(1/2\\pi\\beta)\\log L\\log\\log L}$. The key is a large deviation estimate for the height at the origin in $\\mathbb{Z}^2$, dominated by "harmonic pinnacles", integer approximations of a harmonic variational problem. Second, in this model conditioned on $\\eta\\geq 0$ (a floor), the average height rises, and in fact the height of almost all sites concentrates on levels $H,H+1$ where $H\\sim M/\\sqrt{2}$. This in particular pins down the asymptotics, and corrects the order, in results of Bricmont, El-Mellouki and Fr\\"ohlich (1986), where it was argued that the maximum and the height of the surface above a floor are both of order $\\sqrt{\\log L}$. Finally, our methods extend to other classical surface models (e.g., restricted SOS), featuring connections to $p$-harmonic analysis and alternating sign matrices.

Eyal Lubetzky; Fabio Martinelli; Allan Sly

2014-05-20T23:59:59.000Z

358

Infrared Spectroscopy of Discrete Uranyl Anion Complexes  

SciTech Connect (OSTI)

The Free-Electron Laser for Infrared Experiments, FELIX, was used to study the wavelength-resolved multiphoton dissociation of discrete, gas phase uranyl (UO22+) complexes containing a single anionic ligand (A), with or without ligated solvent molecules (S). The apparent uranyl antisymmetric and symmetric stretching frequencies were measured for complexes with general formula [UO2A(S)n]+, where A was either hydroxide, methoxide or acetate, S was water, ammonia, acetone or acetonitrile, and n = 0-2. The values for the antisymmetric stretching frequency for uranyl ligated with only an anion ([UO2A]+) were as low or lower than measurements for [UO2]2+ ligated with as many as five strong neutral donor ligands, and are comparable to solution phase values. This result was surprising because initial DFT calculations using B3LYP predicted values that were 30 – 40 cm-1 higher, consistent with intuition but not with the data. Modification of the basis set and use of alternative functionals improved computational accuracy for the methoxide and acetate complexes, but calculated values for the hydroxide were greater than the measurement regardless of the computational method used. Attachment of a neutral donor ligand S to [UO2A]+ produced [UO2AS]+, which resulted only very modest changes to the uranyl frequency, and did not universally shift values lower. DFT calculations for [UO2AS]+ were in accord with trends in the data, and showed that attachment of the solvent was accommodated by weakening of the U-anion bond as well as the uranyl. When uranyl frequencies were compared for [UO2AS]+ species having different solvent neutrals, values decreased with increasing neutral nucleophilicity.

Gary S. Groenewold; Anita K. Gianotto; Michael E. McIlwain; Michael J. Van Stipdonk; Michael Kullman; Travis J. Cooper; David T. Moore; Nick Polfer; Jos Oomens; Ivan Infante; Lucas Visscher; Bertrand Siboulet; Wibe A. de Jong

2007-12-01T23:59:59.000Z

359

Infared Spectroscopy of Discrete Uranyl Anion Complexes  

SciTech Connect (OSTI)

The Free-Electron Laser for Infrared Experiments (FELIX) w 1 as used to study the wavelength-resolved multiple photon photodissociation of discrete, gas phase uranyl (UO2 2 2+) complexes containing a single anionic ligand (A), with or without ligated solvent molecules (S). The uranyl antisymmetric and symmetric stretching frequencies were measured for complexes with general formula [UO2A(S)n]+, where A was either hydroxide, methoxide, or acetate; S was water, ammonia, acetone, or acetonitrile; and n = 0-3. The values for the antisymmetric stretching frequency for uranyl ligated with only an anion ([UO2A]+) were as low or lower than measurements for [UO2]2+ ligated with as many as five strong neutral donor ligands, and are comparable to solution phase values. This result was surprising because initial DFT calculations predicted values that were 30–40 cm-1 higher, consistent with intuition but not with the data. Modification of the basis sets and use of alternative functionals improved computational accuracy for the methoxide and acetate complexes, but calculated values for the hydroxide were greater than the measurement regardless of the computational method used. Attachment of a neutral donor ligand S to [UO2A]+ produced [UO2AS]+, which produced only very modest changes to the uranyl antisymmetric stretch frequency, and did not universally shift the frequency to lower values. DFT calculations for [UO2AS]+ were in accord with trends in the data, and showed that attachment of the solvent was accommodated by weakening of the U-anion bond as well as the uranyl. When uranyl frequencies were compared for [UO2AS]+ species having different solvent neutrals, values decreased with increasing neutral nucleophilicity.

Groenewold, G. S.; Gianotto, Anita K.; McIIwain, Michael E.; Van Stipdonk, Michael J.; Kullman, Michael; Moore, David T.; Polfer, Nick; Oomens, Jos; Infante, Ivan A.; Visscher, Lucas; Siboulet, Bertrand; De Jong, Wibe A.

2008-01-24T23:59:59.000Z

360

2-D discrete element modeling of unconsolidated sandstones  

E-Print Network [OSTI]

developed in this thesis is compared to the results of triaxial tests performed in cylindrical core samples of unconsolidated sandstones saturated with heavy oil. The discrete element model treats the sand as a two dimensional assembly of particles...

Franquet Barbara, Javier Alejandro

2012-06-07T23:59:59.000Z

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


361

A piecewise linear finite element discretization of the diffusion equation  

E-Print Network [OSTI]

it discretizes the diffusion equation on an arbitrary polyhedral mesh. We implemented our method in the KULL software package being developed at Lawrence Livermore National Laboratory. This code previously utilized Palmer's method as its diffusion solver, which...

Bailey, Teresa S

2006-10-30T23:59:59.000Z

362

Optimization With Parity Constraints: From Binary Codes to Discrete Integration  

E-Print Network [OSTI]

Optimization With Parity Constraints: From Binary Codes to Discrete Integration Stefano Ermon guarantees on the quality of the solution found. Markov Chain Monte Carlo [17, 21, 32] and Importance

Bejerano, Gill

363

Embed and Project: Discrete Sampling with Universal Hashing  

E-Print Network [OSTI]

Embed and Project: Discrete Sampling with Universal Hashing Stefano Ermon, Carla P. Gomes Dept Markov Chain Monte Carlo (MCMC) methods. MCMC techniques are a specialized form of local search that only

Bejerano, Gill

364

Analysis of steel silo structures on discrete supports   

E-Print Network [OSTI]

The objective of this thesis is to broaden current knowledge of the strength and buckling/collapse of shells, with special reference to steel silo structures on discrete supports, and thus to provide design guidance of ...

Li, Hongyu

365

Resolution of grain scale interactions using the Discrete Element Method  

E-Print Network [OSTI]

Granular materials are an integral part of many engineering systems. Currently, a popular tool for numerically investigating granular systems is the Discrete Element Method (DEM). Nearly all implementations of the DEM, ...

Johnson, Scott M. (Scott Matthew), 1978-

2006-01-01T23:59:59.000Z

366

Discrete Feature Approach for Heterogeneous Reservoir Production Enhancement  

SciTech Connect (OSTI)

The report presents summaries of technology development for discrete feature modeling in support of the improved oil recovery (IOR) for heterogeneous reservoirs. In addition, the report describes the demonstration of these technologies at project study sites.

Dershowitz, William S.; Curran, Brendan; Einstein, Herbert; LaPointe, Paul; Shuttle, Dawn; Klise, Kate

2002-07-26T23:59:59.000Z

367

Critical fermion density for restoring spontaneously broken symmetry  

E-Print Network [OSTI]

We show how the phenomenon of spontaneous symmetry breakdown is affected by the presence of a sea of fermions in the system. When its density exceeds a critical value, the broken symmetry can be restored. We calculate the critical value and discuss the consequences for three different physical systems: First, for the standard model of particle physics, where the spontaneous symmetry breakdown leads nonzero masses of intermediate gauge bosons and fermions. The symmetry restoration will greatly enhance various processes with dramatic consequences for the early universe. Second, for the Gell-Mann--L\\`evy $\\sigma$-model of nuclear physics, where the symmetry breakdown gives rise to the nucleon and meson masses. The symmetry restoration may have important consequences for formation or collapse of stellar cores. Third, for the superconductive phase of condensed-matter, where the BCS condensate at low-temperature may be destroyed by a too large electron density.

Hagen Kleinert; She-Sheng Xue

2014-05-12T23:59:59.000Z

368

On the Thermal Symmetry of the Markovian Master Equation  

E-Print Network [OSTI]

The quantum Markovian master equation of the reduced dynamics of a harmonic oscillator coupled to a thermal reservoir is shown to possess thermal symmetry. This symmetry is revealed by a Bogoliubov transformation that can be represented by a hyperbolic rotation acting on the Liouville space of the reduced dynamics. The Liouville space is obtained as an extension of the Hilbert space through the introduction of tilde variables used in the thermofield dynamics formalism. The angle of rotation depends on the temperature of the reservoir, as well as the value of Planck's constant. This symmetry relates the thermal states of the system at any two temperatures. This includes absolute zero, at which purely quantum effects are revealed. The Caldeira-Leggett equation and the classical Fokker-Planck equation also possess thermal symmetry. We compare the thermal symmetry obtained from the Bogoliubov transformation in related fields and discuss the effects of the symmetry on the shape of a Gaussian wave packet.

B. A. Tay; T. Petrosky

2012-07-25T23:59:59.000Z

369

Symmetry Energy as a Function of Density and Mass  

E-Print Network [OSTI]

Energy in nuclear matter is, in practice, completely characterized at different densities and asymmetries, when the density dependencies of symmetry energy and of energy of symmetric matter are specified. The density dependence of the symmetry energy at subnormal densities produces mass dependence of nuclear symmetry coefficient and, thus, can be constrained by that latter dependence. We deduce values of the mass dependent symmetry coefficients, by using excitation energies to isobaric analog states. The coefficient systematic, for intermediate and high masses, is well described in terms of the symmetry coefficient values of a_a^V=(31.5-33.5) MeV for the volume coefficient and a_a^S=(9-12) MeV for the surface coefficient. These two further correspond to the parameter values describing density dependence of symmetry energy, of L~95 MeV and K_{sym}~25 MeV.

Pawel Danielewicz; Jenny Lee

2007-08-21T23:59:59.000Z

370

Symmetry Energy as a Function of Density and Mass  

SciTech Connect (OSTI)

Energy in nuclear matter is, in practice, completely characterized at different densities and asymmetries, when the density dependencies of symmetry energy and of energy of symmetric matter are specified. The density dependence of the symmetry energy at subnormal densities produces mass dependence of nuclear symmetry coefficient and, thus, can be constrained by that latter dependence. We deduce values of the mass dependent symmetry coefficients, by using excitation energies to isobaric analog states. The coefficient systematic, for intermediate and high masses, is well described in terms of the symmetry coefficient values of a{sub a}{sup V} = (31.5-33.5) MeV for the volume coefficient and a{sub a}{sup S} = (9-12) MeV for the surface coefficient. These two further correspond to the parameter values describing density dependence of symmetry energy, of L{approx}95 MeV and K{sub sym}{approx}25 MeV.

Danielewicz, Pawel; Lee, Jenny [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States)

2007-10-26T23:59:59.000Z

371

Symmetry Energy as a Function of Density and Mass  

E-Print Network [OSTI]

Energy in nuclear matter is, in practice, completely characterized at different densities and asymmetries, when the density dependencies of symmetry energy and of energy of symmetric matter are specified. The density dependence of the symmetry energy at subnormal densities produces mass dependence of nuclear symmetry coefficient and, thus, can be constrained by that latter dependence. We deduce values of the mass dependent symmetry coefficients, by using excitation energies to isobaric analog states. The coefficient systematic, for intermediate and high masses, is well described in terms of the symmetry coefficient values of a_a^V=(31.5-33.5) MeV for the volume coefficient and a_a^S=(9-12) MeV for the surface coefficient. These two further correspond to the parameter values describing density dependence of symmetry energy, of L~95 MeV and K_{sym}~25 MeV.

Danielewicz, Pawel

2007-01-01T23:59:59.000Z

372

Symmetries of Differential equations and Applications in Relativistic Physics  

E-Print Network [OSTI]

In this thesis, we study the one parameter point transformations which leave invariant the differential equations. In particular we study the Lie and the Noether point symmetries of second order differential equations. We establish a new geometric method which relates the point symmetries of the differential equations with the collineations of the underlying manifold where the motion occurs. This geometric method is applied in order the two and three dimensional Newtonian dynamical systems to be classified in relation to the point symmetries; to generalize the Newtonian Kepler-Ermakov system in Riemannian spaces; to study the symmetries between classical and quantum systems and to investigate the geometric origin of the Type II hidden symmetries for the homogeneous heat equation and for the Laplace equation in Riemannian spaces. At last but not least, we apply this geometric approach in order to determine the dark energy models by use the Noether symmetries as a geometric criterion in modified theories of gra...

Paliathanasis, Andronikos

2015-01-01T23:59:59.000Z

373

Isolation of Discrete Nanoparticle-DNA Conjugates for Plasmonic Applications  

SciTech Connect (OSTI)

Discrete DNA-gold nanoparticle conjugates with DNA lengths as short as 15 bases for both 5 nm and 20 nm gold particles have been purified by anion-exchange HPLC. Conjugates comprising short DNA (<40 bases) and large gold particles (>_ 20 nm) are difficult to purify by other means, and are potential substrates for plasmon coupling experiments. Conjugate purity is demonstrated by hybridizing complementary conjugates to form discrete structures, which are visualized by TEM.

Alivisatos, Paul; Claridge, Shelley A.; Liang, Huiyang W.; Basu, Sourav Roger; Frechet, Jean M.J.; Alivisatos, A. Paul

2008-04-11T23:59:59.000Z

374

Direct measurement of yield stress of discrete materials  

E-Print Network [OSTI]

We present a novel computational method for direct measurement of yield stress of discrete materials. The method is well-suited for the measurement of jamming phase diagram of a wide range of discrete particle systems such as granular materials, foams, and colloids. We further successfully apply the method to evaluate the jamming phase diagram of wet granular material in order to demonstrates the applicability of the model.

S. H. Ebrahimnazhad Rahbari; J. Vollmer; S. Herminghaus; M. Brinkmann

2012-06-09T23:59:59.000Z

375

Fractional Equations of Kicked Systems and Discrete Maps  

E-Print Network [OSTI]

Starting from kicked equations of motion with derivatives of non-integer orders, we obtain "fractional" discrete maps. These maps are generalizations of well-known universal, standard, dissipative, kicked damped rotator maps. The main property of the suggested fractional maps is a long-term memory. The memory effects in the fractional discrete maps mean that their present state evolution depends on all past states with special forms of weights. These forms are represented by combinations of power-law functions.

Vasily E. Tarasov; George M. Zaslavsky

2011-07-20T23:59:59.000Z

376

Non-Hermitian Hamiltonians with unitary and antiunitary symmetries  

SciTech Connect (OSTI)

We analyse several non-Hermitian Hamiltonians with antiunitary symmetry from the point of view of their point-group symmetry. It enables us to predict the degeneracy of the energy levels and to reduce the dimension of the matrices necessary for the diagonalization of the Hamiltonian in a given basis set. We can also classify the solutions according to the irreducible representations of the point group and thus analyse their properties separately. One of the main results of this paper is that some PT-symmetric Hamiltonians with point-group symmetry C{sub 2v} exhibit complex eigenvalues for all values of a potential parameter. In such cases the PT phase transition takes place at the trivial Hermitian limit which suggests that the phenomenon is not robust. Point-group symmetry enables us to explain such anomalous behaviour and to choose a suitable antiunitary operator for the PT symmetry. -- Highlights: •PT-symmetric Hamiltonians exhibit real eigenvalues when PT symmetry is unbroken. •PT-symmetric multidimensional oscillators appear to show PT phase transitions. •This transition was conjectured to be a high-energy phenomenon. •We show that point group symmetry is useful for predicting broken PT symmetry in multidimensional oscillators. •PT-symmetric oscillators with C{sub 2v} symmetry exhibit phase transitions at the trivial Hermitian limit.

Fernández, Francisco M., E-mail: fernande@quimica.unlp.edu.ar; Garcia, Javier

2014-03-15T23:59:59.000Z

377

Understanding the Electroweak Symmetry Breaking: The Higgs Boson...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Understanding the Electroweak Symmetry Breaking: The Higgs Boson and Beyond (Monday, March 2) DATE: Monday, March 2, 4:10 pm LOCATION: Physics 0003 Understanding the Electroweak...

378

Symmetry Breaking in Graphene Gregory S. Boebinger, National...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Symmetry Breaking in Graphene Gregory S. Boebinger, National High Magnetic Field Laboratory DMR-Award 0654118 DC Field Facility While the laws of physics are often symmetric,...

379

Symmetry energy at subnuclear densities deduced from nuclear masses  

E-Print Network [OSTI]

We examine how nuclear masses are related to the density dependence of the symmetry energy. Using a macroscopic nuclear model we calculate nuclear masses in a way dependent on the equation of state of asymmetric nuclear matter. We find by comparison with empirical two-proton separation energies that a smaller symmetry energy at subnuclear densities, corresponding to a larger density symmetry coefficient L, is favored. This tendency, which is clearly seen for nuclei that are neutron-rich, nondeformed, and light, can be understood from the property of the surface symmetry energy in a compressible liquid-drop picture.

Kazuhiro Oyamatsu; Kei Iida

2010-04-19T23:59:59.000Z

380

Dynamical electroweak symmetry breaking and the top quark  

SciTech Connect (OSTI)

In this talk, I discuss theories of dynamical electroweak symmetry breaking, with emphasis on the implications of a heavy top quark on the weak interaction {rho} parameter.

Chivukula, R.S. [Boston Univ., MA (United States)

1997-01-01T23:59:59.000Z

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


381

Symmetry Energy Effects on the Nuclear Landscape  

E-Print Network [OSTI]

While various mean-field models predict similar two-proton drip line in the nuclear landscape, their predictions for the two-neutron drip line involve extreme extrapolations and exhibit a significant variation. We demonstrate that this variation is mainly due to the different values of the symmetry energy $E_{\\rm{sym}}(\\rho_{\\rm{c}})$ at the subsaturation cross density $\\rho_{\\rm{c}}\\approx 0.11$ fm$^{-3}$ for different interactions. Based on the recent accurate constraint on $E_{\\rm{sym}}(\\rho_{\\rm{c}})$, we obtain a quite precise prediction for the location of the two-neutron drip line and thus a very precise estimate of $1981 \\pm 76$ for the number of bound even-even nuclei with proton number between $2$ and $120$ among which only $799$ have so far been discovered experimentally.

Rui Wang; Lie-Wen Chen

2014-10-09T23:59:59.000Z

382

Separability and dynamical symmetry of Quantum Dots  

SciTech Connect (OSTI)

The separability and Runge–Lenz-type dynamical symmetry of the internal dynamics of certain two-electron Quantum Dots, found by Simonovi? et al. (2003), are traced back to that of the perturbed Kepler problem. A large class of axially symmetric perturbing potentials which allow for separation in parabolic coordinates can easily be found. Apart from the 2:1 anisotropic harmonic trapping potential considered in Simonovi? and Nazmitdinov (2013), they include a constant electric field parallel to the magnetic field (Stark effect), the ring-shaped Hartmann potential, etc. The harmonic case is studied in detail. -- Highlights: • The separability of Quantum Dots is derived from that of the perturbed Kepler problem. • Harmonic perturbation with 2:1 anisotropy is separable in parabolic coordinates. • The system has a conserved Runge–Lenz type quantity.

Zhang, P.-M., E-mail: zhpm@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou (China); Zou, L.-P., E-mail: zoulp@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou (China); Horvathy, P.A., E-mail: horvathy@lmpt.univ-tours.fr [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou (China); Laboratoire de Mathématiques et de Physique Théorique, Tours University (France); Gibbons, G.W., E-mail: G.W.Gibbons@damtp.cam.ac.uk [Department of Applied Mathematics and Theoretical Physics, Cambridge University, Cambridge (United Kingdom)

2014-02-15T23:59:59.000Z

383

Quantum symmetry and photoreactivity of azabenzenes  

SciTech Connect (OSTI)

The fundamental processes associated with a photochemical reaction are described with reference to experimental properties of azabenzenes. Consideration of both excitation and relaxation processes led to presentation of the symmetry propagator, a unifying principle which maps system fluctuations (perturbations acting on an initial state) with dissipations (transitions to different states), thus directing the energy flow along competing reactive and nonreactive pathways. A coherent picture of relaxation processes including chemical reactions was constructed with the aid of spectroscopic data. Pyrazine (1,4 diazine) possesses vibronically active modes which provide an efficient mechanism for internal conversion to the first excited singlet state, where other promoting modes of the correct symmetry induce both intersystem crossing to the triplet manifold, isomerization through diaza-benzvalene, and chemical reactions through cycloreversion of dewar pyrazine to yield HCN plus an azete. At higher energies simple H atom loss and internal conversion become more predominant, leading to ring opening followed by elimination of methylene nitrile and ground state reaction products. Efficiency of chemical transformations as dissipation mechanisms versus competing fluorescence, phosphorescence and radiationless relaxation was mapped from near ultraviolet to far ultraviolet by photodissociation quantum yields into reaction channels characterized by molecular beam photofragment translational spectroscopy. A reaction path model for azabenzene photochemistry was presented and tested against experiment. Presence of undiscovered channels in other azabenzene systems was predicted and verified. The dominant process, HCN elimination, was resolved into three distinct channels. Both molecular and atomic hydrogen elimination was observed, the former with significant vibrational excitation. Small yields of isomerization products, acetylene and N2, were also observed.

Chesko, J.D.M.

1995-06-01T23:59:59.000Z

384

Asymptotic Stability of Heteroclinic Cycles in Systems with Symmetry, II  

E-Print Network [OSTI]

Asymptotic Stability of Heteroclinic Cycles in Systems with Symmetry, II Martin Krupa #3; Ian heteroclinic cycles that persist under perturbations that respect the symmetry. In previous work, we began a system- atic investigation into the asymptotic stability of such cycles. In particular, we found a su

385

Energy Content of Colliding Plane Waves using Approximate Noether Symmetries  

E-Print Network [OSTI]

This paper is devoted to study the energy content of colliding plane waves using approximate Noether symmetries. For this purpose, we use approximate Lie symmetry method of Lagrangian for differential equations. We formulate the first-order perturbed Lagrangian for colliding plane electromagnetic and gravitational waves. It is shown that in both cases, there does not exist

M. Sharif; Saira Waheed

2011-09-19T23:59:59.000Z

386

ess5011 Robert J. Serfling MULTIVARIATE SYMMETRY AND  

E-Print Network [OSTI]

ess5011 Robert J. Serfling MULTIVARIATE SYMMETRY AND ASYMMETRY Robert J. Serfling University by modern group theory. 1 #12;ess5011 Robert J. Serfling Here we focus on the notion of symmetry and s independently distributed as chi-square with m degrees of freedom. 2 #12;ess5011 Robert J. Serfling An important

Serfling, Robert

387

Development of an Interhemispheric Symmetry Measurement in the Neonatal Brain  

E-Print Network [OSTI]

Development of an Interhemispheric Symmetry Measurement in the Neonatal Brain Ninah Koolen1.dereymaeker, katrien.jansen, jan.vervisch, gunnar.naulaers}@uzleuven.be Keywords: Preterm Brain, Symmetry, Channel of different brain regions will allow detecting physiologic asymmetry versus pathologic asymmetry. This can

388

Symmetry Energy from Systematic of Isobaric Analog States  

E-Print Network [OSTI]

Excitation energies to isobaric states, that are analogs of ground states, are dominated by contributions from the symmetry energy. This opens up a possibility of investigating the symmetry energy on nucleus-by-nucleus basis. Upon correcting energies of measured nuclear levels for shell and pairing effects, we find that the lowest energies for a given isospin rise in proportion to the square of isospin, allowing for an interpretation of the coefficient of proportionality in terms of a symmetry coefficient for a given nucleus. In the (A,Z) regions where there are enough data, we demonstrate a Z-independence of that coefficient. We further concentrate on the A-dependence of the coefficient, in order to learn about the density dependence of symmetry energy in uniform matter, given the changes of the density in the surface region. In parallel to the analysis of data, we carry out an analysis of the coefficient for nuclei calculated within the Skyrme-Hartree-Fock (SHF) approach, with known symmetry energy for uniform matter. While the data from isobaric analog states suggest a simple interpretation for the A-dependent symmetry coefficient, in terms of the surface and volume symmetry coefficients, the SHF results point to a more complicated situation within the isovector sector than in the isoscalar, with much stronger curvature effects in the first. We exploit the SHF results in estimating the curvature contributions to the symmetry coefficient. That assessment is hampered by instabilities of common Skyrme parameterizations of nuclear interactions.

Pawel Danielewicz; Jenny Lee

2011-11-01T23:59:59.000Z

389

Dynamical constants of structured photons with parabolic-cylindrical symmetry  

E-Print Network [OSTI]

Electromagnetic modes with parabolic-cylindrical symmetry and their dynamical variables are studied both in the classical and quantum realm. As a result, a new dynamical constant for the electromagnetic field is identified and linked to the symmetry operator which supports it.

B. M. Rodriguez-Lara; R. Jauregui

2009-05-20T23:59:59.000Z

390

Symmetry in CSP solutions Nicoleta Neagu and Boi Faltings  

E-Print Network [OSTI]

Symmetry in CSP solutions Nicoleta Neagu and Boi Faltings Artificial Intelligence Laboratory (LIA for finding symmetric solutions of in a CSP. This method is using local symmetries of the CSP structure and research upon searching CSP solutions but few of them watch the relations between CSP solutions. In certain

Flener, Pierre

391

New symmetries in mixed-integer linear optimization  

E-Print Network [OSTI]

Besides the usual permutation of variables, these symmetries can also take the ... Having a list of generators of the group of constraint symmetries we can just ... Speed has its price, since this method cannot hope to cover all the solutions that ..... lifted form, the algorithm can be custom tailored to operate only on the original

2013-11-15T23:59:59.000Z

392

Gell-Mann-Oakes-Renner relation for multiple chiral symmetries  

E-Print Network [OSTI]

As a first step towards considering a chiral perturbation theory for overlap fermions, we investigate whether there are any ambiguities in the expression for the pion mass resulting from multiple chiral symmetries. The concern is that, calculating the conserved current for Ginsparg Wilson chiral symmetries in the usual way, different expressions of the chiral symmetries lead to different currents. This implies an ambiguity in the definition of the pion and pion decay constant for all Ginsparg-Wilson expressions of the Dirac operator, including the overlap operator. We use a renormalisation group mapping procedure to consider local chiral symmetry transformations for a continuum Ginsparg-Wilson "Dirac-operator." We find that this naturally leads to an expression for the conserved current that differs from the standard expression by cut-off artefacts, but is independent of which of the Ginsparg-Wilson symmetries is chosen. We recover the standard expressions for the massive Dirac operator, propagator, and chira...

Cundy, Nigel

2011-01-01T23:59:59.000Z

393

To see Symmetry in a Forest of Trees  

E-Print Network [OSTI]

The exact symmetry identities among four-point tree-level amplitudes of bosonic open string theory as derived by G. W. Moore are re-examined. The main focuses of this work are: (1) Explicit construction of kinematic configurations and a new polarization basis for the scattering processes. These setups simplify greatly the functional forms of the exact symmetry identities, and help us to extract easily high-energy limits of stringy amplitudes appearing in the exact identities. (2) Connection and comparison between D. J. Gross's high-energy stringy symmetry and the exact symmetry identities as derived by G. W. Moore. (3) Observation of symmetry patterns of stringy amplitudes with respect to the order of energy dependence in scattering amplitudes.

Chuan-Tsung Chan; Shoichi Kawamoto; Dan Tomino

2014-05-30T23:59:59.000Z

394

7.10 MATLAB Experiment on Discrete-Time Systems Purpose: In this experiment, we analyze time responses of a higher-order linear discrete-  

E-Print Network [OSTI]

7.10 MATLAB Experiment on Discrete-Time Systems Purpose: In this experiment, we analyze time responses of a higher-order linear discrete- time system using MATLAB. We study system impulse, step-time dynamic systems using MATLAB. Consider the linear discrete-time system

Gajic, Zoran

395

Discrete Intrinsic Redshifts from Quasars to Normal Galaxies  

E-Print Network [OSTI]

It is pointed out that the discrete velocities found by Tifft in galaxies are harmonically related to the discrete intrinsic redshifts found in quasars. All are harmonically related to the constant 0.062 +/- 0.001, and this is the fourth independent analysis in which the redshift increment 0.062 has been shown to be significant. It is concluded that there is a quantized component in the redshift of both quasars and galaxies that has a common origin and is unlikely to be Doppler-related.

M. B. Bell

2002-11-05T23:59:59.000Z

396

Methodology for characterizing modeling and discretization uncertainties in computational simulation  

SciTech Connect (OSTI)

This research effort focuses on methodology for quantifying the effects of model uncertainty and discretization error on computational modeling and simulation. The work is directed towards developing methodologies which treat model form assumptions within an overall framework for uncertainty quantification, for the purpose of developing estimates of total prediction uncertainty. The present effort consists of work in three areas: framework development for sources of uncertainty and error in the modeling and simulation process which impact model structure; model uncertainty assessment and propagation through Bayesian inference methods; and discretization error estimation within the context of non-deterministic analysis.

ALVIN,KENNETH F.; OBERKAMPF,WILLIAM L.; RUTHERFORD,BRIAN M.; DIEGERT,KATHLEEN V.

2000-03-01T23:59:59.000Z

397

Nuclear breathing mode in neutron-rich Nickel isotopes: sensitivity to the symmetry energy and the role of the continuum  

E-Print Network [OSTI]

In this new era of radioactive beam facilities, the discovery of novel modes of excitation in nuclei far away from stability represents an area of intense research activity. In addition, these modes of excitation appear to be sensitive to the uncertain density dependence of the symmetry energy. We study the emergence, evolution, and nature of both the soft and giant isoscalar monopole modes as a function of neutron excess in three unstable Nickel isotopes: 56Ni, 68Ni, and 78Ni. The distribution of isoscalar monopole strength is computed in a relativistic random-phase approximation using several accurately calibrated effective interactions. In particular, a non-spectral Green's function approach is adopted that allows for an exact treatment of the continuum without any reliance on discretization. The discretization of the continuum is neither required nor admitted. In the case of 56Ni, the lack of low-energy strength results in a direct correlation between the centroid energy of the giant monopole resonance and the incompressibility coefficient of symmetric nuclear matter. In contrast, the large neutron excess in both 68Ni and 78Ni generates a significant, yet relatively featureless, amount of low-energy strength that is driven by transitions into the continuum. Moreover, the evolution of monopole strength with neutron excess displays sensitivity to the density dependence of the symmetry energy. Our results suggest that future measurements of the distribution of isoscalar monopole strength at radioactive beam facilities using a very long chain of both stable and unstable isotopes could place important constraints on the equation of state of neutron-rich matter and ultimately on the properties of neutron stars. However, given the nature of the low-energy monopole excitations, a proper treatment of the continuum is essential.

J. Piekarewicz

2014-10-14T23:59:59.000Z

398

SciTech Connect: Sphericity and symmetry breaking in the formation...  

Office of Scientific and Technical Information (OSTI)

and symmetry breaking in the formation of FrankKasper phases from one component materials Citation Details In-Document Search Title: Sphericity and symmetry breaking in the...

399

Turbulent heat transfer and friction in a square channel with discrete rib turbulators  

E-Print Network [OSTI]

in which two opposite walls are roughened with parallel and crossed arrays of full ribs, cross-cut discrete ribs, and beveled discrete ribs. The discrete ribs are staggered in alternate rows of three and two ribs The rib-roughened channel models..., 000 and 80, 000. Results are also obtained for parallel arrays of cross-cut discrete ribs with a = 45 and ? 45' on alternate rows. Both parallel angled cross-cut and beveled discrete ribs are superior to 90" discrete ribs and corresponding parallel...

McMillin, Robert Dale

1989-01-01T23:59:59.000Z

400

Symmetry related dynamics in parallel shear flows  

E-Print Network [OSTI]

Parallel shear flows come with continuous symmetries of translation in the downstream and spanwise direction. As a consequence, flow states that differ in their spanwise or downstream location but are otherwise identical are dynamically equivalent. In the case of travelling waves, this trivial degree of freedom can be removed by going to a frame of reference that moves with the state, thereby turning the travelling wave in the laboratory frame to a fixed point in the comoving frame of reference. We here discuss a general method by which the translational displacements can be removed also for more complicated and dynamically active states and demonstrate its application for several examples. For flows states in the asymptotic suction boundary layer we show that in the case of the long-period oscillatory edge state we can find local phase speeds which remove the fast oscillations and reveal the slow vortex dynamics underlying the burst phenomenon. For spanwise translating states we show that the method removes the drift but not the dynamical events that cause the big spanwise displacement. For a turbulent case we apply the method to the spanwise shifts and find slow components that are correlated over very long times. Calculations for plane Poiseuille flow show that the long correlations in the transverse motions are not special to the asymptotic suction boundary layer.

Tobias Kreilos; Stefan Zammert; Bruno Eckhardt

2014-04-23T23:59:59.000Z

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


401

Radiation Reaction, Renormalization and Poincaré Symmetry  

E-Print Network [OSTI]

We consider the self-action problem in classical electrodynamics of a massive point-like charge, as well as of a massless one. A consistent regularization procedure is proposed, which exploits the symmetry properties of the theory. The radiation reaction forces in both 4D and 6D are derived. It is demonstrated that the Poincar\\'e-invariant six-dimensional electrodynamics of the massive charge is renormalizable theory. Unlike the massive case, the rates of radiated energy-momentum tend to infinity whenever the source is accelerated. The external electromagnetic fields, which do not change the velocity of the particle, admit only its presence within the interaction area. The effective equation of motion is the equation for eigenvalues and eigenvectors of the electromagnetic tensor. The interference part of energy-momentum radiated by two massive point charges arbitrarily moving in flat spacetime is evaluated. It is shown that the sum of work done by Lorentz forces of charges acting on one another exhausts the effect of combination of outgoing electromagnetic waves generated by the charges.

Yurij Yaremko

2005-11-25T23:59:59.000Z

402

Charge symmetry breaking in $\\Lambda$ hypernuclei revisited  

E-Print Network [OSTI]

The large charge symmetry breaking (CSB) implied by the $\\Lambda$ binding energy difference $\\Delta B^{4}_{\\Lambda}(0^+_{\\rm g.s.})\\equiv B_{\\Lambda}(_{\\Lambda}^4$He)$-$$B_{\\Lambda}(_{\\Lambda}^4$H) = 0.35$\\pm$0.06 MeV of the $A=4$ mirror hypernuclei ground states, determined from emulsion studies, has defied theoretical attempts to reproduce it in terms of CSB in hyperon masses and in hyperon-nucleon interactions, including one pion exchange arising from $\\Lambda-\\Sigma^0$ mixing. Using a schematic strong-interaction $\\Lambda N\\leftrightarrow\\Sigma N$ coupling model developed by Akaishi and collaborators for $s$-shell $\\Lambda$ hypernuclei, we revisit the evaluation of CSB in the $A=4$ $\\Lambda$ hypernuclei and extend it to $p$-shell mirror $\\Lambda$ hypernuclei. The model yields values of $\\Delta B^{4}_{\\Lambda} (0^+_{\\rm g.s.})\\sim 0.25$ MeV. Smaller size and mostly negative $p$-shell binding energy differences are calculated for the $A=7-10$ mirror hypernuclei, in rough agreement with the few available dat...

Gal, Avraham

2015-01-01T23:59:59.000Z

403

Coupled Oscillator Systems Having Partial PT Symmetry  

E-Print Network [OSTI]

This paper examines chains of $N$ coupled harmonic oscillators. In isolation, the $j$th oscillator ($1\\leq j\\leq N$) has the natural frequency $\\omega_j$ and is described by the Hamiltonian $\\frac{1}{2}p_j^2+\\frac{1}{2}\\omega_j^2x_j^2$. The oscillators are coupled adjacently with coupling constants that are purely imaginary; the coupling of the $j$th oscillator to the $(j+1)$st oscillator has the bilinear form $i\\gamma x_jx_{j+1}$ ($\\gamma$ real). The complex Hamiltonians for these systems exhibit {\\it partial} $\\mathcal{PT}$ symmetry; that is, they are invariant under $i\\to-i$ (time reversal), $x_j\\to-x_j$ ($j$ odd), and $x_j\\to x_j$ ($j$ even). [They are also invariant under $i\\to-i$, $x_j\\to x_j$ ($j$ odd), and $x_j\\to- x_j$ ($j$ even).] For all $N$ the quantum energy levels of these systems are calculated exactly and it is shown that the ground-state energy is real. When $\\omega_j=1$ for all $j$, the full spectrum consists of a real energy spectrum embedded in a complex one; the eigenfunctions correspondi...

Beygi, Alireza; Bender, Carl M

2015-01-01T23:59:59.000Z

404

Time reversal symmetry and collapse models  

E-Print Network [OSTI]

Collapse models are modifications of quantum theory where the wave function is treated as physically real and the collapse of the wave function is a physical process. This appears to introduce a time reversal asymmetry into the dynamics of the wave function since the collapses affect only the future state. This paper challenges this conclusion, showing that in three different examples of time asymmetries associated with collapse models, if the physically real part of the model can be reduced to the locations in space and time about which collapses occur, then such a model works both forward and backward in time, in each case satisfying the Born rule. Despite the apparent asymmetry of the collapse process, these models in fact have time reversal symmetry. Any physically observed time asymmetries that arise in such models are due to the asymmetric imposition of initial or final time boundary conditions, rather than from an inherent asymmetry in the dynamical law. This is the standard explanation of time asymmetric behaviour resulting from time symmetric laws.

Daniel Bedingham; Owen Maroney

2015-02-24T23:59:59.000Z

405

NMR STUDY OF MOLECULAR REFORIENTATION UNDER FIVEFOLD SYMMETRY SOLID PERMETHYLFERROCENE  

SciTech Connect (OSTI)

The ring reorientation in permethylferrocene has been studied using high resolution solid state {sup 13}C NMR. The constraints which symmetry places upon the number and types of motional parameters which may be determined from the NMR spectrum are discussed. From comparison of the experimental lineshapes in the slow reorientation temperatures range with theoretical models for random rotations and symmetry related jumps, it is concluded that the reorientation occurs as jumps between symmetry related orientations with jumps of 2{pi}/5 highly favored over 4{pi}/5. The activation energy derived for the jump process is 13.5 kjoules/mole.

Wemmer, D.E.; Ruben, D.J.; Pines, A.

1980-08-01T23:59:59.000Z

406

Non-relativistic conformal symmetries in fluid mechanics  

E-Print Network [OSTI]

The symmetries of a free incompressible fluid span the Galilei group, augmented with independent dilations of space and time. When the fluid is compressible, the symmetry is enlarged to the expanded Schroedinger group, which also involves, in addition, Schroedinger expansions. While incompressible fluid dynamics can be derived as an appropriate non-relativistic limit of a conformally-invariant relativistic theory, the recently discussed Conformal Galilei group, obtained by contraction from the relativistic conformal group, is not a symmetry. This is explained by the subtleties of the non-relativistic limit.

P. -M. Zhang; P. A. Horvathy

2009-10-24T23:59:59.000Z

407

Symmetry groups of non-stationary planar ideal plasticity  

E-Print Network [OSTI]

This paper is a study of the Lie groups of point symmetries admitted by a system describing a non-stationary planar flow of an ideal plastic material. For several types of forces involved in the system, the infinitesimal generators which generate the Lie algebra of symmetries have been obtained. In the case of a monogenic force, the classification of one- and two- dimensional subalgebras into conjugacy classes under the action of the group of automorphisms has been accomplished. The method of symmetry reduction is applied for certain subalgebra classes in order to obtain invariant solutions.

Vincent Lamothe

2014-09-30T23:59:59.000Z

408

Constraints on the density dependence of the symmetry energy  

E-Print Network [OSTI]

Collisions involving 112Sn and 124Sn nuclei have been simulated with the improved Quantum Molecular Dynamics transport model. The results of the calculations reproduce isospin diffusion data from two different observables and the ratios of neutron and proton spectra. By comparing these data to calculations performed over a range of symmetry energies at saturation density and different representations of the density dependence of the symmetry energy, constraints on the density dependence of the symmetry energy at sub-normal density are obtained. Results from present work are compared to constraints put forward in other recent analysis.

M. B. Tsang; Yingxun Zhang; P. Danielewicz; M. Famiano; Zhuxia Li; W. G. Lynch; A. W. Steiner

2008-11-19T23:59:59.000Z

409

Constraints on the Density Dependence of the Symmetry Energy  

SciTech Connect (OSTI)

Collisions involving {sup 112}Sn and {sup 124}Sn nuclei have been simulated with the improved quantum molecular dynamics transport model. The results of the calculations reproduce isospin diffusion data from two different observables and the ratios of neutron and proton spectra. By comparing these data to calculations performed over a range of symmetry energies at saturation density and different representations of the density dependence of the symmetry energy, constraints on the density dependence of the symmetry energy at subnormal density are obtained. The results from the present work are compared to constraints put forward in other recent analyses.

Tsang, M. B.; Danielewicz, P.; Lynch, W. G.; Steiner, A. W. [Joint Institute of Nuclear Astrophysics and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Physics and Astronomy Department, Michigan State University, East Lansing, Michigan 48824 (United States); Zhang Yingxun [Joint Institute of Nuclear Astrophysics and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); China Institute of Atomic Energy, P.O. Box 275 (18), Beijing 102413 (China); Famiano, M. [Physics Department, Western Michigan University, Kalamazoo, Michigan 49008 (United States); Li, Zhuxia [China Institute of Atomic Energy, P.O. Box 275 (18), Beijing 102413 (China)

2009-03-27T23:59:59.000Z

410

Constraints on the density dependence of the symmetry energy  

E-Print Network [OSTI]

Collisions involving 112Sn and 124Sn nuclei have been simulated with the improved Quantum Molecular Dynamics transport model. The results of the calculations reproduce isospin diffusion data from two different observables and the ratios of neutron and proton spectra. By comparing these data to calculations performed over a range of symmetry energies at saturation density and different representations of the density dependence of the symmetry energy, constraints on the density dependence of the symmetry energy at sub-normal density are obtained. Results from present work are compared to constraints put forward in other recent analysis.

Tsang, M B; Danielewicz, P; Famiano, M; Li, Zhuxia; Lynch, W G; Steiner, A W

2008-01-01T23:59:59.000Z

411

Symmetry energy from fragment observables in the canonical thermodynamic model  

E-Print Network [OSTI]

Different formulas relying measurable fragment isotopic observables to the symmetry energy of excited nuclei have been proposed and applied to the analysis of heavy ion collision data in the recent literature. In this paper we examine the quality of the different expressions in the framework of the McGill Canonical Thermodynamic Model. We show that even in the idealized situation of canonical equilibrium and in the absence of secondary decay, these formulas do not give a precise reconstruction of the symmetry energy of the fragmenting source. However, both isotopic widths and isoscaling appear very well correlated to the physical symmetry energy.

G. Chaudhuri; F. Gulminelli; S. Das Gupta

2009-10-19T23:59:59.000Z

412

Excitation energy dependence of symmetry energy of finite nuclei  

E-Print Network [OSTI]

A finite range density and momentum dependent effective interaction is used to calculate the density and temperature dependence of the symmetry energy coefficient Csym(rho,T) of infinite nuclear matter. This symmetry energy is then used in the local density approximation to evaluate the excitation energy dependence of the symmetry energy coefficient of finite nuclei in a microcanonical formulation that accounts for thermal and expansion effects. The results are in good harmony with the recently reported experimental data from energetic nucleus-nucleus collisions.

S. K. Samaddar; J. N. De; X. Vinas; M. Centelles

2007-10-11T23:59:59.000Z

413

Hawking Radiation by Kerr Black Holes and Conformal Symmetry  

SciTech Connect (OSTI)

The exponential blueshift associated with the event horizon of a black hole makes conformal symmetry play a fundamental role in accounting for its thermal properties. Using a derivation based on two-point functions, we show that the full spectrum of thermal radiation of scalar particles by Kerr black holes can be explicitly derived on the basis of a conformal symmetry arising in the wave equation near the horizon. The simplicity of our approach emphasizes the depth of the connection between conformal symmetry and black hole radiance.

Agullo, Ivan; Parker, Leonard [Physics Department, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, Wisconsin 53201 (United States); Navarro-Salas, Jose [Departamento de Fisica Teorica and IFIC, Centro Mixto Universidad de Valencia-CSIC. Facultad de Fisica, Universidad de Valencia, Burjassot-46100, Valencia (Spain); Olmo, Gonzalo J. [Instituto de Estructura de la Materia, CSIC, Serrano 121, 28006 Madrid (Spain)

2010-11-19T23:59:59.000Z

414

Wave-packet continuum discretization for quantum scattering  

E-Print Network [OSTI]

A general approach to a solution of few- and many-body scattering problems based on a continuum-discretization procedure is described in detail. The complete discretization of continuous spectrum is realized using stationary wave packets which are the normalized states constructed from exact non-normalized continuum states. Projecting the wave functions and all scattering operators like $t$-matrix, resolvent, etc. on such a wave-packet basis results in a formulation of quantum scattering problem entirely in terms of discrete elements and linear equations with regular matrices. It is demonstrated that there is a close relation between the above stationary wave packets and pseudostates which are employed often to approximate the scattering states with a finite $L_2$ basis. Such a fully discrete treatment of complicated few- and many-body scattering problems leads to significant simplification of their practical solution. Also we get finite-dimensional approximations for complicated operators like effective interactions between composite particles constructed via the Feshbach-type projection formalism. As illustrations to this general approach we consider several important particular problems including multichannel scattering and scattering in the three-nucleon system within the Faddeev framework.

O. A. Rubtsova; V. I. Kukulin; V. N. Pomerantsev

2015-01-15T23:59:59.000Z

415

Discrete Mathematics 110 (1992) 43-59 North-Holland  

E-Print Network [OSTI]

' or `combine' de Bruijn cycles? (vii) What are the analogues for larger alphabets (k symbols rather than 2Discrete Mathematics 110 (1992) 43-59 North-Holland 43 Universal structures Fan Chung cycles Revised 12 April 1991 Abstract Chung, F., P. Diaconis and R. Graham, Universal cycles for combinatorial

Diaconis, Persi

416

Discrete Ordinate Method for Solving Inhomogeneous Vector Radiative Transfer Equation  

E-Print Network [OSTI]

paper.. This type of equation appears when modeling radiative transport in plane parallel media. WeDiscrete Ordinate Method for Solving Inhomogeneous Vector Radiative Transfer Equation We describe here a solution method for equations of the type given by: µ I(,µ) +I(,µ)- () 2 1 -1 Z(,µ,µ )I(,µ )dµ

Pattanaik, Sumanta N.

417

Sparse Twisted Tensor Frame Discretization Parametric Transport Operators  

E-Print Network [OSTI]

Parametric, high-dimensional transport Equations such as Vlasov-Poisson, Boltzmann and Radiative Transfer associated with the transport equation and by subsequent Galerkin discretization with a novel, sparse tensor of the phase space. In [22], for a model parametric transport problem arising in radiative transport, the use

Grohs, Philipp

418

Two samples test for discrete power-law distributions  

E-Print Network [OSTI]

Power-law distributions occur in wide variety of physical, biological, and social phenomena. In this paper, we propose a statistical hypothesis test based on the log-likelihood ratio to assess whether two samples of discrete data are drawn from the same power-law distribution.

Bessi, Alessandro

2015-01-01T23:59:59.000Z

419

Continuous-Time Distributed Observers with Discrete Communication  

E-Print Network [OSTI]

Continuous-Time Distributed Observers with Discrete Communication Florian D¨orfler, Fabio-permissions@ieee.org. This material is based upon work supported by NSF grants IIS-0904501 and CPS-1135819. Florian D¨orfler, Fabio, University of California, Santa Barbara, {dorfler,fabiopas,bullo}@engineering.ucsb.edu Distributed observers

Bullo, Francesco

420

Time-Variant Channel Equalization via Discrete Prolate Spheroidal Sequences  

E-Print Network [OSTI]

are processed by an inverse discrete Fourier transform (DFT) to obtain an orthogonal frequency division Devices department (RCD), part of the Siemens AG Austria, Program and System Engineering (PSE) and the Telecommunications Research Center Vienna (ftw.) in the I0 project. Thomas Zemen was with Siemens AG Austria when he

Zemen, Thomas

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


421

Discrete geodesic regression in shape space Benjamin Berkels1  

E-Print Network [OSTI]

Discrete geodesic regression in shape space Benjamin Berkels1 , P. Thomas Fletcher2 , Behrend Benedikt.Wirth@cims.nyu.edu Abstract. A new approach for the effective computation of geodesic re- gression curves in shape spaces is presented. Here, one asks for a geodesic curve on the shape manifold

Rumpf, Martin

422

Discrete wave turbulence of rotational capillary water waves  

E-Print Network [OSTI]

We study the discrete wave turbulent regime of capillary water waves with constant non-zero vorticity. The explicit Hamiltonian formulation and the corresponding coupling coefficient are obtained. We also present the construction and investigation of resonance clustering. Some physical implications of the obtained results are discussed.

Adrian Constantin; Elena Kartashova; Erik Wahlén

2010-05-12T23:59:59.000Z

423

Power Control for Discrete-Input Block-Fading Channels  

E-Print Network [OSTI]

. K. Rasmussen CUED / F-INFENG / TR 582 August 2007 #12;#12;1 Power Control for Discrete-Input Block-Fading Channels Khoa D. Nguyen, Albert Guill´en i F`abregas and Lars K. Rasmussen Abstract We consider power systems employing orthogonal frequency division multiplexing. K. D. Nguyen and L. K. Rasmussen

Guillén i Fàbregas, Albert

424

Simulation on Discrete Fracture Network Using Flexible Voronoi Gridding  

E-Print Network [OSTI]

........................................... 3 1.2.2 Gridding Techniques ............................................................. 4 1.2.2.1 Globally Orthogonal Grid ...................................... 5 1.2.2.2 Corner Point Grid... ................................................... 5 1.2.3 Locally Orthogonal Grid ....................................................... 6 1.3 Introduction to Discrete Fracture Network Simulation ................... 7 1.4 Introduction to Fracture Aperture Measurement Using X-Ray CT...

Syihab, Zuher

2011-02-22T23:59:59.000Z

425

3D discrete rotations using hinge angles Yohan Thibaulta,  

E-Print Network [OSTI]

3D discrete rotations using hinge angles Yohan Thibaulta, , Akihiro Sugimotob , Yukiko Kenmochia a of Informatics, Japan Abstract In this paper, we study 3D rotations on grid points computed by using only integers. For that purpose, we investigate the intersection between the 3D half- grid and the rotation

Paris-Sud XI, Université de

426

Fractal algebras of discretization sequences Steffen Roch (TU Darmstadt)  

E-Print Network [OSTI]

Abstract Fractal algebras of discretization sequences Steffen Roch (TU Darmstadt) First a warning: Fractality, in the sense of these lectures, has nothing to do with fractal geometries or broken dimensions or other involved things. Rather, the notion fractal algebra had been chosen in order to emphasize

Potts, Daniel

427

Controlling Wild Mobile Robots Using Virtual Gates and Discrete Transitions  

E-Print Network [OSTI]

Controlling Wild Mobile Robots Using Virtual Gates and Discrete Transitions Leonardo Bobadilla purposely design them to execute wild motions, which means each will strike every open set infinitely often, "wildly behaving" robots that move more-or-less straight until a wall is contacted. They then pick

LaValle, Steven M.

428

Discrete Applied Mathematics 121 (2002) 139153 NeST graphs  

E-Print Network [OSTI]

Discrete Applied Mathematics 121 (2002) 139­153 NeST graphs Ryan B. Haywarda; , Paul E. Kearneyb; received in revised form 14 March 2001; accepted 26 March 2001 Abstract We establish results on NeST graphs show the equivalence of proper NeST graphs and unit NeST graphs, the equivalence of ÿxed distance NeST

Hayward, Ryan B.

429

Energy-Efficient Discrete Cosine Transform on Ronald Scrofano  

E-Print Network [OSTI]

Energy-Efficient Discrete Cosine Transform on FPGAs Ronald Scrofano Department of Computer Science is brought to mobile devices, it becomes important that it is possible to calculate the DCT in an energy-efficient the DCT with a linear array of PEs. This design is optimized for energy efficiency. We analyze the energy

Jang, Ju-Wook

430

Discrete fracture modeling for fractured reservoirs using Voronoi grid blocks  

E-Print Network [OSTI]

or pseudofracture groups modeled in their own grid blocks. Discrete Fracture Modeling (DFN) is still a relatively new field, and most research on it up to this point has been done with Delaunay tessellations. This research investigates an alternative approach using...

Gross, Matthew Edward

2007-09-17T23:59:59.000Z

431

Coded Adaptive Linear Precoded Discrete Multitone Over PLC Channel  

E-Print Network [OSTI]

Coded Adaptive Linear Precoded Discrete Multitone Over PLC Channel Fahad Syed Muhammmad, Jean- DMT system is presented in the power line communication (PLC) context with a loading algorithm which spectral density constraint. Using a multipath model of PLC channel, it is shown that the proposed coded

Boyer, Edmond

432

Finite Element Discretization Strategies for the Inverse Electrocardiographic (ECG) Problem  

E-Print Network [OSTI]

Finite Element Discretization Strategies for the Inverse Electrocardiographic (ECG) Problem Dafang electrocardiographic (ECG) problems re- quires the ability to both quantify and minimize approxi- mation errors specifically for the inverse ECG prob- lem. By quantitatively analyzing the connection between the ill

Utah, University of

433

Extreme-Point Stability Tests for Discrete-Time Polynomials  

E-Print Network [OSTI]

TA9 -10:40 Extreme-Point Stability Tests for Discrete-Time Polynomials F. PCrez *, C been an increasinginterest in finding extreme- point results for the study of stability of uncertain in the coefficients space where Schur stability of the extremes im- plies the stability of the entire family 12). Our

434

New symmetry properties of pointlike scalar and Dirac particles  

E-Print Network [OSTI]

New symmetry properties are found for pointlike scalar and Dirac particles (Higgs boson and all leptons) in Riemannian spacetimes in the presence of electromagnetic interactions. A Hermitian form of the Klein-Gordon equation for a pointlike scalar particle in an arbitrary n-dimensional Riemannian spacetime is obtained. New conformal symmetries of initial and Hermitian forms of this equation are ascertained. In the above spacetime, general Hamiltonians in the generalized Feshbach-Villars and Foldy-Wouthuysen representations are derived. The conformal-like transformation conserving these Hamiltonians is found. Corresponding conformal symmetries of a Dirac particle are determined. It is proven that all conformal symmetries remain unchanged by an inclusion of electromagnetic interactions.

Alexander J. Silenko

2015-01-15T23:59:59.000Z

435

On a Broken Formal Symmetry between Kinetic and Gravitational Energy  

E-Print Network [OSTI]

Historically, the discovery of symmetries has played an important role in the progress of our fundamental understanding of nature. This paper will demonstrate that there exists in Newtonian theory in a spherical gravitational field a formal symmetry between the kinetic (KE) and gravitational potential energy (GPE) of a test mass. Put differently, there exists a way of expressing GPE such that the form of the mathematical expression remains invariant under an interchange of KE and GPE. When extended to relativity by a suitable assumption, it leads to a framework that bridges the general relativistic and Newtonian conceptions of gravitational energy, even though the symmetry is broken except in the infinitesimal limit. Recognizing this symmetry at infinitesimal scales makes it possible to write a relativistic equation of an individual graviton, the properties of which under under one interpretation may be unexpected.

Armin Nikkhah Shirazi

2014-07-16T23:59:59.000Z

436

ISO(4,1) Symmetry in the EFT of Inflation  

E-Print Network [OSTI]

In DBI inflation the cubic action is a particular linear combination of the two, otherwise independent, cubic operators \\dot \\pi^3 and \\dot \\pi (\\partial_i \\pi)^2. We show that in the Effective Field Theory (EFT) of inflation this is a consequence of an approximate 5D Poincar\\'e symmetry, ISO(4,1), non-linearly realized by the Goldstone \\pi. This symmetry uniquely fixes, at lowest order in derivatives, all correlation functions in terms of the speed of sound c_s. In the limit c_s \\to 1, the ISO(4,1) symmetry reduces to the Galilean symmetry acting on \\pi. On the other hand, we point out that the non-linear realization of SO(4,2), the isometry group of 5D AdS space, does not fix the cubic action in terms of c_s.

Paolo Creminelli; Razieh Emami; Marko Simonovi?; Gabriele Trevisan

2014-02-27T23:59:59.000Z

437

ISO(4,1) symmetry in the EFT of inflation  

SciTech Connect (OSTI)

In DBI inflation the cubic action is a particular linear combination of the two, otherwise independent, cubic operators ?-dot {sup 3} and ?-dot (?{sub i}?){sup 2}. We show that in the Effective Field Theory (EFT) of inflation this is a consequence of an approximate 5D Poincar and apos;e symmetry, ISO(4,1), non-linearly realized by the Goldstone ?. This symmetry uniquely fixes, at lowest order in derivatives, all correlation functions in terms of the speed of sound c{sub s}. In the limit c{sub s} ? 1, the ISO(4,1) symmetry reduces to the Galilean symmetry acting on ?. On the other hand, we point out that the non-linear realization of SO(4,2), the isometry group of 5D AdS space, does not fix the cubic action in terms of c{sub s}.

Creminelli, Paolo [Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151, Trieste (Italy); Emami, Razieh [School of Physics, Institute for Research in Fundamental Sciences (IPM), P. O. Box 19395-5531, Teheran (Iran, Islamic Republic of); Simonovi?, Marko; Trevisan, Gabriele, E-mail: creminel@ictp.it, E-mail: emami@mail.ipm.ir, E-mail: msimonov@sissa.it, E-mail: gtrevi@sissa.it [Scuola Internazionale Superiore di Studi Avanzati (SISSA), via Bonomea 265, 34136, Trieste (Italy)

2013-07-01T23:59:59.000Z

438

Symmetry in exterior boundary value problems for quasilinear ...  

E-Print Network [OSTI]

symmetry for the solution u and for the condenser ?i when the overdetermined boundary condition |Du| = c > 0 on d?i is imposed. This provides a new proof of a

439

Euclidean Dynamical Symmetry in Nuclear Shape Phase Transitions  

E-Print Network [OSTI]

The Euclidean dynamical symmetry hidden in the critical region of nuclear shape phase transitions is revealed by a novel algebraic F(5) description. With a nonlinear projection, it is shown that the dynamics in the critical region of the spherical--axial deformed and the spherical--$\\gamma$ soft shape phase transitions can indeed be manifested by this description, which thus provides a unified symmetry--based interpretation of the critical phenomena in the region.

Yu Zhang; Yu-Xin Liu; Feng Pan; Yang Sun; J. P. Draayer

2014-11-26T23:59:59.000Z

440

Quantum-gravity phenomenology, Lorentz symmetry, and the SME  

E-Print Network [OSTI]

Violations of spacetime symmetries have recently been identified as promising signatures for physics underlying the Standard Model. The present talk gives an overview over various topics in this field: The motivations for spacetime-symmetry research, including some mechanisms for Lorentz breaking, are reviewed. An effective field theory called the Standard-Model Extension (SME) for the description of the resulting low-energy effects is introduced, and some experimental tests of Lorentz and CPT invariance are listed.

Ralf Lehnert

2007-03-16T23:59:59.000Z

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


441

Density dependence of symmetry free energy of hot nuclei  

E-Print Network [OSTI]

The density and excitation energy dependence of symmetry energy and symmetry free energy for finite nuclei are calculated microscopically in a microcanonical framework taking into account thermal and expansion effects. A finite-range momentum and density dependent two-body effective interaction is employed for this purpose. The role of mass, isospin and equation of state (EoS) on these quantities is also investigated; our calculated results are in consonance with the available experimental data.

S. K. Samaddar; J. N. De; X. Vinas; M. Centelles

2008-09-04T23:59:59.000Z

442

Anatomy of symmetry energy of dilute nuclear matter  

E-Print Network [OSTI]

The symmetry energy coefficients of dilute clusterized nuclear matter are evaluated in the $S$-matrix framework. Employing a few different definitions commonly used in the literature for uniform nuclear matter, it is seen that the different definitions lead to perceptibly different results for the symmetry coefficients for dilute nuclear matter. They are found to be higher compared to those obtained for uniform matter in the low density domain. The calculated results are in reasonable consonance with those extracted recently from experimental data.

J. N. De; S. K. Samaddar; B. K. Agrawal

2010-09-23T23:59:59.000Z

443

Symmetry energy for fragmentation in dynamical nuclear collisions  

SciTech Connect (OSTI)

We extract values for the free symmetry energy as a function of the fragment size (the proton number Z) from antisymmetrized molecular dynamics calculations of calcium collisions. Simple statistical physics describe well the distribution of hot nuclei at breakup, provided the surface symmetry term in the free energy is much smaller at high excitation than in ground state nuclei. This result may reflect the condition of low density and finite temperature when these systems disassemble.

Ono, Akira [Department of Physics, Tohoku University, Sendai 980-8578 (Japan); Danielewicz, P.; Lynch, W.G.; Tsang, M.B. [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States); Friedman, W.A. [Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States)

2004-10-01T23:59:59.000Z

444

Analysis of Dual Consistency for Discontinuous Galerkin Discretizations of Source Terms  

E-Print Network [OSTI]

The effects of dual consistency on discontinuous Galerkin discretizations of solution and solution gradient dependent source terms are examined. Two common discretizations are analyzed: the standard weighting technique for ...

Darmofal, David L.

445

Linearisation of the (M,K)-reduced non-autonomous discrete periodic KP equation  

E-Print Network [OSTI]

The (M,K)-reduced non-autonomous discrete KP equation is linearised on the Picard group of an algebraic curve. As an application, we construct theta function solutions to the initial value problem of some special discrete KP equation.

Shinsuke Iwao

2009-12-17T23:59:59.000Z

446

An energy-preserving muscle tissue model: formulation and compatible discretizations  

E-Print Network [OSTI]

An energy-preserving muscle tissue model: formulation and compatible discretizations D. Chapelle ­ phenomena associated with these energy considerations. Keywords: muscle tissue modeling; myocardium; multiscale; energy balance; time and space discretizations 1 Introduction The modeling of the active

Paris-Sud XI, Université de

447

Accounting for StreamAquifer Interactions in the State-Space Discretization of the  

E-Print Network [OSTI]

­Milyukov­Nash Cascade for Streamflow Forecasting Jozsef Szilagyi1 Abstract: A sample-data system discretization

Szilagyi, Jozsef

448

Pseudo-Hermiticity versus PT-Symmetry III: Equivalence of pseudo-Her miticity and the presence of antilinear symmetries  

E-Print Network [OSTI]

We show that a diagonalizable (non-Hermitian) Hamiltonian H is pseudo-Hermitian if and only if it has an antilinear symmetry, i.e., a symmetry generated by an invertible antilinear operator. This implies that the eigenvalues of H are real or come in complex conjugate pairs if and only if H possesses such a symmetry. In particular, the reality of the spectrum of H implies the presence of an antilinear symmetry. We further show that the spectrum of H is real if and only if there is a positive-definite inner-product on the Hilbert space with respect to which H is Hermitian or alternatively there is a pseudo-canonical transformation of the Hilbert space that maps H into a Hermitian operator.

Ali Mostafazadeh

2002-05-07T23:59:59.000Z

449

Breakdown of 2mm symmetry in electron diffraction from multiwalled carbon nanotubes  

E-Print Network [OSTI]

Breakdown of 2mm symmetry in electron diffraction from multiwalled carbon nanotubes Zejian Liu of single-walled carbon nanotubes always have 2mm symmetry regardless if the nanotubes them- selves have such symmetry. We here show that, for the case of multiwalled carbon nanotubes, the 2mm symmetry can break down

Qin, Lu-Chang

450

TIME DISCRETE GEODESIC PATHS IN THE SPACE OF IMAGES B. BERKELS, A. EFFLAND, M. RUMPF  

E-Print Network [OSTI]

TIME DISCRETE GEODESIC PATHS IN THE SPACE OF IMAGES B. BERKELS, A. EFFLAND, M. RUMPF Abstract and intensity variation. A robust and effective variational time discretization of geodesics paths is proposed requirements for the input images, the existence of discrete geodesic paths defined as minimizers

Rumpf, Martin

451

DISCRETE GEODESIC CALCULUS IN THE SPACE OF VISCOUS FLUIDIC MARTIN RUMPF AND BENEDIKT WIRTH  

E-Print Network [OSTI]

DISCRETE GEODESIC CALCULUS IN THE SPACE OF VISCOUS FLUIDIC OBJECTS MARTIN RUMPF AND BENEDIKT WIRTH cheap dissimilarity measure, a time discrete geodesic calculus is developed, and applications to shape in shape space. The notion of discrete geodesics defined as energy minimizing paths gives rise

Rumpf, Martin

452

A DUALITY APPROACH TO THE GENEALOGIES OF DISCRETE NON-NEUTRAL WRIGHT-FISHER MODELS  

E-Print Network [OSTI]

A DUALITY APPROACH TO THE GENEALOGIES OF DISCRETE NON-NEUTRAL WRIGHT-FISHER MODELS THIERRY E formu- lae still are of great use when considering discrete non-neutral Wright-Fisher models, Running title: Duality and Discrete Non-Neutral Wright-Fisher Models. Keywords: Wright-Fisher Models

Paris-Sud XI, Université de

453

CERNA WORKING PAPER SERIES Patent quality and value in discrete and cumulative innovation  

E-Print Network [OSTI]

1 CERNA WORKING PAPER SERIES Patent quality and value in discrete and cumulative innovation Justus,version2-16Nov2010 #12;2 Patent Quality and Value in Discrete and Cumulative Innovation Cerna Working the relationship between patent quality and patent value in discrete and cumulative innovation. Using factor

Paris-Sud XI, Université de

454

Econometric Analysis of Discrete-Valued Irregularly-Spaced Financial Transactions Data Using a New Autoregressive Conditional Multinomial Model  

E-Print Network [OSTI]

Lancaster, T. , 1990, The Econometric Analysis of TransitionDEPARTMENT OF ECONOMICS ECONOMETRIC ANALYSIS OF DISCRETE-PAPER 98-10 APRIL 1998 Econometric analysis of discrete-

Russell, Jeffrey; Engle, Robert F

1998-01-01T23:59:59.000Z

455

Monte Carlo solution of a semi-discrete transport equation  

SciTech Connect (OSTI)

The authors present the S{sub {infinity}} method, a hybrid neutron transport method in which Monte Carlo particles traverse discrete space. The goal of any deterministic/stochastic hybrid method is to couple selected characters from each of the methods in hopes of producing a better method. The S{sub {infinity}} method has the features of the lumped, linear-discontinuous (LLD) spatial discretization, yet it has no ray-effects because of the continuous angular variable. They derive the S{sub {infinity}} method for the solid-state, mono-energetic transport equation in one-dimensional slab geometry with isotropic scattering and an isotropic internal source. They demonstrate the viability of the S{sub {infinity}} method by comparing their results favorably to analytic and deterministic results.

Urbatsch, T.J.; Morel, J.E.; Gulick, J.C.

1999-09-01T23:59:59.000Z

456

A discrete model for compressible flows in heterogeneous media  

SciTech Connect (OSTI)

This work deals with the building of a discrete model able to describe and to predict the evolution of complex gas flows in heterogeneous media. In many physical applications, large scales numerical simulation is no longer possible because of a lack of computing resources. Indeed the medium topology may be complex due to the presence of many obstacles (walls, pipes, equipments, geometric singularities etc.). Aircraft powerplant compartments are examples where topology is complex due to the presence of pipes, ducts, coolers and other equipment. Other important examples are gas explosions and large scale dispersion of hazardous materials in urban places, cities or underground involving obstacles such as buildings and various infrastructures. In all cases efficient safety responses are required. Then a new discrete model is built and solved in reasonable execution times for large cells volumes including such obstacles. Quantitative comparisons between experimental and numerical results are shown for different significant test cases, showing excellent agreement.

Le Metayer, O., E-mail: Olivier.Lemetayer@polytech.univ-mrs.f [IUSTI, UMR CNRS 6595, Universite Aix-Marseille I, Technopole de Chateau Gombert, 5 Rue E. Fermi, 13453 Marseille Cedex 13 (France); SMASH project, INRIA, 2004 route des Lucioles, 06902 Sophia Antipolis (France); Massol, A., E-mail: Alexandre.Massol@airbus.co [AIRBUS Operations SAS, Coc Powerplant, EDET30, M0112/5, 316 Route de Bayonne, 31060 Toulouse Cedex 09 (France); Favrie, N., E-mail: Nicolas.Favrie@polytech.univ-mrs.f [IUSTI, UMR CNRS 6595, Universite Aix-Marseille I, Technopole de Chateau Gombert, 5 Rue E. Fermi, 13453 Marseille Cedex 13 (France); SMASH project, INRIA, 2004 route des Lucioles, 06902 Sophia Antipolis (France); Hank, S., E-mail: Sarah.Hank@polytech.univ-mrs.f [IUSTI, UMR CNRS 6595, Universite Aix-Marseille I, Technopole de Chateau Gombert, 5 Rue E. Fermi, 13453 Marseille Cedex 13 (France); SMASH project, INRIA, 2004 route des Lucioles, 06902 Sophia Antipolis (France)

2011-04-01T23:59:59.000Z

457

Fast Computation Algorithm for Discrete Resonances among Gravity Waves  

E-Print Network [OSTI]

Traditionally resonant interactions among short waves, with large real wave-numbers, were described statistically and only a small domain in spectral space with integer wave-numbers, discrete resonances, had to be studied separately in resonators. Numerical simulations of the last few years showed unambiguously the existence of some discrete effects in the short-waves part of the wave spectrum. Newly presented model of laminated turbulence explains theoretically appearance of these effects thus putting a novel problem - construction of fast algorithms for computation of solutions of resonance conditions with integer wave-numbers of order $10^3$ and more. Example of such an algorithm for 4-waves interactions of gravity waves is given. Its generalization on the different types of waves is briefly discussed.

Elena Kartashova

2006-05-25T23:59:59.000Z

458

The Discrete Geometry of a Small Causal Diamond  

E-Print Network [OSTI]

We study the discrete causal set geometry of a small causal diamond in a curved spacetime using the average abundance of k-element chains or total orders in the underlying causal set C. We begin by obtaining the first order curvature corrections to the flat spacetime expression for the abundance using Riemann normal coordinates. For fixed spacetime dimension this allows us to find a new expression for the discrete scalar curvature of C as well as the time-time component of its Ricci tensor in terms of the abundances of k-chains. We also find a new dimension estimator for C which replaces the flat spacetime Myrheim-Meyer estimator in generic curved spacetimes.

Mriganko Roy; Debdeep Sinha; Sumati Surya

2012-12-04T23:59:59.000Z

459

The discrete Kalman filtering approach for seismic signals deconvolution  

SciTech Connect (OSTI)

Seismic signals are a convolution of reflectivity and seismic wavelet. One of the most important stages in seismic data processing is deconvolution process; the process of deconvolution is inverse filters based on Wiener filter theory. This theory is limited by certain modelling assumptions, which may not always valid. The discrete form of the Kalman filter is then used to generate an estimate of the reflectivity function. The main advantage of Kalman filtering is capability of technique to handling continually time varying models and has high resolution capabilities. In this work, we use discrete Kalman filter that it was combined with primitive deconvolution. Filtering process works on reflectivity function, hence the work flow of filtering is started with primitive deconvolution using inverse of wavelet. The seismic signals then are obtained by convoluting of filtered reflectivity function with energy waveform which is referred to as the seismic wavelet. The higher frequency of wavelet gives smaller wave length, the graphs of these results are presented.

Kurniadi, Rizal; Nurhandoko, Bagus Endar B. [Departement of Physics Intitut Teknologi Bandung, Jl. Ganesha 10 Bandung (Indonesia)

2012-06-20T23:59:59.000Z

460

Quantum Mechanics and Discrete Time from "Timeless" Classical Dynamics  

E-Print Network [OSTI]

We study classical Hamiltonian systems in which the intrinsic proper time evolution parameter is related through a probability distribution to the physical time, which is assumed to be discrete. - This is motivated by the ``timeless'' reparametrization invariant model of a relativistic particle with two compactified extradimensions. In this example, discrete physical time is constructed based on quasi-local observables. - Generally, employing the path-integral formulation of classical mechanics developed by Gozzi et al., we show that these deterministic classical systems can be naturally described as unitary quantum mechanical models. The emergent quantum Hamiltonian is derived from the underlying classical one. It is closely related to the Liouville operator. We demonstrate in several examples the necessity of regularization, in order to arrive at quantum models with bounded spectrum and stable groundstate.

H. -T. Elze

2003-07-03T23:59:59.000Z

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


461

Renormalized waves and discrete breathers in $?$-FPU chains  

E-Print Network [OSTI]

We demonstrate via numerical simulation that in the \\textit{strongly} nonlinear limit, the $\\beta$-FPU system in thermal equilibrium behaves surprisingly like weakly nonlinear waves in properly renormalized normal variables. This arises because the collective effect of strongly nonlinear interactions effectively renormalizes linear dispersion frequency and leads to effectively weak interaction among these renormalized waves. Furthermore, we show that the dynamical scenario for thermalized $\\beta$-FPU chains is spatially highly localized discrete breathers riding chaotically on spatially extended, renormalized waves.

Boris Gershgorin; Yuri V. Lvov; David Cai

2005-08-20T23:59:59.000Z

462

Discrete quadratic solitons with competing second-harmonic components  

SciTech Connect (OSTI)

We describe families of discrete solitons in quadratic waveguide arrays supported by competing cascaded nonlinear interactions between one fundamental and two second-harmonic modes. We characterize the existence, stability, and excitation dynamics of these solitons and show that their features may resemble those of solitons in saturable media. Our results also demonstrate that a power threshold may appear for soliton formation, leading to a suppression of beam self-focusing which explains recent experimental observations.

Setzpfandt, Frank; Pertsch, Thomas [Institute of Applied Physics, Abbe Center of Photonics, Friedrich-Schiller-Universitaet Jena, Max-Wien-Platz 1, D-07743 Jena (Germany); Sukhorukov, Andrey A. [Nonlinear Physics Center, Research School of Physics and Engineering, Australian National University, Canberra, 0200 ACT (Australia)

2011-11-15T23:59:59.000Z

463

Heuristic Optimization for the Discrete Virtual Power Plant Dispatch Problem  

SciTech Connect (OSTI)

We consider a virtual power plant, which is given the task of dispatching a fluctuating power supply to a portfolio of flexible consumers. The flexible consumers are modeled as discrete batch processes, and the associated optimization problem is denoted the discrete virtual power plant dispatch problem (DVPPDP). First, the nondeterministic polynomial time (NP)-completeness of the discrete virtual power plant dispatch problem is proved formally. We then proceed to develop tailored versions of the meta-heuristic algorithms hill climber and greedy randomized adaptive search procedure (GRASP). The algorithms are tuned and tested on portfolios of varying sizes. We find that all the tailored algorithms perform satisfactorily in the sense that they are able to find sub-optimal, but usable, solutions to very large problems (on the order of 105 units) at computation times on the scale of just 10 s, which is far beyond the capabilities of the optimal algorithms we have tested. In particular, GRASP sorted shows with the most promising performance, as it is able to find solutions that are both agile (sorted) and well balanced, and consistently yields the best numerical performance among the developed algorithms.

Petersen, Mette K.; Hansen, Lars H.; Bendtsen, Jan; Edlund, Kristian; Stoustrup, Jakob

2014-10-17T23:59:59.000Z

464

Gell-Mann-Oakes-Renner relation for multiple chiral symmetries  

E-Print Network [OSTI]

As a first step towards considering a chiral perturbation theory for overlap fermions, we investigate whether there are any ambiguities in the expression for the pion mass resulting from multiple chiral symmetries. The concern is that, calculating the conserved current for Ginsparg Wilson chiral symmetries in the usual way, different expressions of the chiral symmetries lead to different currents. This implies an ambiguity in the definition of the pion and pion decay constant for all Ginsparg-Wilson expressions of the Dirac operator, including the overlap operator. We use a renormalisation group mapping procedure to consider local chiral symmetry transformations for a continuum Ginsparg-Wilson "Dirac-operator." We find that this naturally leads to an expression for the conserved current that differs from the standard expression by cut-off artefacts, but is independent of which of the Ginsparg-Wilson symmetries is chosen. We recover the standard expressions for the massive Dirac operator, propagator, and chiral condensate. With this in place, we proceed to calculate the pion mass in the mapped theory as a function of the quark mass, and discover a unique expression for $F_\\pi$ and $m_\\pi$, recovering the usual Gell-Mann-Oakes-Renner relation, baring the substitution of the chiral condensate with its modified value. We hypothesise that the argument can be carried directly over to the lattice theory.

Nigel Cundy; Weonjong Lee

2011-11-11T23:59:59.000Z

465

Symmetry Energy from Systematic of Isobaric Analog States  

E-Print Network [OSTI]

Excitation energies to isobaric states, that are analogs of ground states, are dominated by contributions from the symmetry energy. This opens up a possibility of investigating the symmetry energy on nucleus-by-nucleus basis. Upon correcting energies of measured nuclear levels for shell and pairing effects, we find that the lowest energies for a given isospin rise in proportion to the square of isospin, allowing for an interpretation of the coefficient of proportionality in terms of a symmetry coefficient for a given nucleus. In the (A,Z) regions where there are enough data, we demonstrate a Z-independence of that coefficient. We further concentrate on the A-dependence of the coefficient, in order to learn about the density dependence of symmetry energy in uniform matter, given the changes of the density in the surface region. In parallel to the analysis of data, we carry out an analysis of the coefficient for nuclei calculated within the Skyrme-Hartree-Fock (SHF) approach, with known symmetry energy for unif...

Danielewicz, Pawel

2011-01-01T23:59:59.000Z

466

Quantum coherence, time-translation symmetry and thermodynamics  

E-Print Network [OSTI]

The first law of thermodynamics imposes not just a constraint on the energy-content of systems in extreme quantum regimes, but also symmetry-constraints related to the thermodynamic processing of quantum coherence. We show that this thermodynamic symmetry decomposes any quantum state into mode operators that quantify the coherence present in the state. We then establish general upper and lower bounds for the evolution of quantum coherence under arbitrary thermal operations, valid for any temperature. We identify primitive coherence manipulations and show that the transfer of coherence between energy levels manifests irreversibility not captured by free energy. Moreover, the recently developed thermo-majorization relations on block-diagonal quantum states are observed to be special cases of this symmetry analysis.

Matteo Lostaglio; Kamil Korzekwa; David Jennings; Terry Rudolph

2015-04-13T23:59:59.000Z

467

Consistency condition for inflation from (broken) conformal symmetry  

SciTech Connect (OSTI)

We investigate the symmetry constraints on the bispectrum, i.e. the three-point correlation function of primordial density fluctuations, in slow-roll inflation. It follows from the defining property of slow-roll inflation that primordial correlation functions inherit most of their structure from weakly broken de Sitter symmetries. Using holographic techniques borrowed from the AdS/CFT correspondence, the symmetry constraints on the bispectrum can be mapped to a set of stress-tensor Ward identities in a weakly broken 2+1-dimensional Euclidean CFT. We construct the consistency condition from these Ward identities using conformal perturbation theory. This requires a second order Ward identity and the use of the evolution equation. Our result also illustrates a subtle difference between conformal perturbation theory and the slow-roll expansion.

Schalm, Koenraad; Aalst, Ted van der [Instituut-Lorentz for Theoretical Physics, Universiteit Leiden, Niels Bohrweg 2, Leiden (Netherlands); Shiu, Gary, E-mail: kschalm@lorentz.leidenuniv.nl, E-mail: shiu@physics.wisc.edu, E-mail: vdaalst@lorentz.leidenuniv.nl [Department of Physics, University of Wisconsin-Madison, Madison, WI 53706 (United States)

2013-03-01T23:59:59.000Z

468

Symmetry group analysis of an ideal plastic flow  

E-Print Network [OSTI]

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.

Vincent Lamothe

2011-02-11T23:59:59.000Z

469

Symmetry and Conservation Laws in Semiclassical Wave Packet Dynamics  

E-Print Network [OSTI]

We formulate translational and rotational symmetries in semiclassical Gaussian wave packet dynamics and find the corresponding conserved quantities via Noether's theorem. We consider two slightly different formulations of Gaussian wave packet dynamics; one is based on earlier works of Heller and Hagedorn, and the other based on the symplectic-geometric approach by Lubich and others. In either case, we reveal the symplectic and Hamiltonian nature of the dynamics and formulate natural symmetry group actions in the setting to derive the corresponding conserved quantities (momentum maps). Of particular interest is the momentum map corresponding to the rotational symmetry in the symplectic formulation of the Gaussian wave packet dynamics: We obtain a semiclassical angular momentum that inherits the essential properties of the classical angular momentum as well as naturally corresponds to the quantum picture.

Tomoki Ohsawa

2014-10-30T23:59:59.000Z

470

Role of density dependent symmetry energy in nuclear stopping  

E-Print Network [OSTI]

Information about the nuclear matter under the extreme conditions of temperature and density and the role of symmetry energy under these conditions is still a topic of crucial importance in the present day nuclear physics research. The multifragmentation, collective flow and the nuclear stopping is among the various rare phenomenon which can be observed in heavy-ion collisions at intermediate energies. The nuclear stopping, which is sensitive towards the symmetry energy has gained a lot of interest because it provides the possibility to examine the degree of thermalization or equilibration in the matter. Aim of the present study is to pin down the nuclear stopping for the different forms of density dependent symmetry energy

Karan Singh Vinayak; Suneel Kumar

2011-07-27T23:59:59.000Z

471

Charge Symmetry Breaking and Parity Violating Electron-Proton Scattering  

E-Print Network [OSTI]

Charge symmetry breaking contributions to the proton's neutral weak form factors must be understood in order for future measurements of parity violating electron-proton scattering to be definitively interpreted as evidence of proton strangeness. We calculate these charge symmetry breaking form factor contributions using chiral perturbation theory with resonance saturation estimates for unknown low-energy constants. The uncertainty of the leading-order resonance saturation estimates is reduced by incorporating nuclear physics constraints. Higher-order contributions are investigated through phenomenological vertex form factors. We predict that charge symmetry breaking form factor contributions are an order of magnitude larger than expected from naive dimensional analysis but are still an order of magnitude smaller than current experimental bounds on proton strangeness. This is consistent with previous calculations using chiral perturbation theory with resonance saturation.

Michael Wagman; Gerald A. Miller

2014-12-16T23:59:59.000Z

472

Dynamical entanglement versus symmetry and dynamics of classical approximations  

SciTech Connect (OSTI)

It is shown that dynamical entanglement between two qubits depends on the symmetry of the quantum model. On the other hand, the latter is reflected in the qualitative properties of the dynamics of a classical approximation of the quantum system. For generic separable pure initial states, the dynamical entanglement is larger if the system is less symmetric and its classical approximation is chaotic. The influence of different types of Markov environments on the established relation between the dynamical entanglement, symmetry and the classical dynamics is also studied.

Buric, Nikola [Department of Physics and Mathematics, Faculty of Pharmacy, University of Beograd, Vojvode Stepe 450, 11000 Belgrade (Serbia and Montenegro)

2006-05-15T23:59:59.000Z

473

The origin of order in random matrices with symmetries  

E-Print Network [OSTI]

From Noether's theorem we know symmetries lead to conservation laws. What is left to nature is the ordering of conserved quantities; for example, the quantum numbers of the ground state. In physical systems the ground state is generally associated with `low' quantum numbers and symmetric, low-dimensional irreps, but there is no \\textit{a priori} reason to expect this. By constructing random matrices with nontrivial point-group symmetries, I find the ground state is always dominated by extremal low-dimensional irreps. Going further, I suggest this explains the dominance of J=0 g.s. even for random two-body interactions.

Calvin W. Johnson

2012-06-25T23:59:59.000Z

474

CPT- and Lorentz-symmetry breaking: a review  

E-Print Network [OSTI]

The breakdown of spacetime symmetries has recently been identified as a promising candidate signal for underlying physics, possibly arising through quantum-gravitational effects. This talk gives an overview over various aspects of CPT- and Lorentz-violation research. Particular emphasis is given to the interplay between CPT, Lorentz, and translation symmetry, mechanisms for CPT and Lorentz breaking, and the construction of a low-energy quantum-field description of such effect. This quantum field framework, called the SME, is employed to determine possible phenomenological consequences of CPT and Lorentz violation for neutral-meson interferometry.

Ralf Lehnert

2006-12-28T23:59:59.000Z

475

Symmetries of geodesic motion in Gödel-type spacetimes  

E-Print Network [OSTI]

In this paper, we study Noether gauge symmetries of geodesic motion for geodesic Lagrangian of four classes of metrics of G\\"{o}del-type spacetimes for which we calculated the Noether gauge symmetries for all classes I-IV, and find the first integrals of corresponding classes to derive a complete characterization of the geodesic motion. Using the obtained expressions for $\\dot{t}, \\dot{r}, \\dot{\\phi}$ and $\\dot{z}$ of each classes I-IV which depends essentially on two independent parameters $m$ and $w$, we explicitly integrated the geodesic equations of motion for the corresponding G\\"{o}del-type spacetimes.

U. Camci

2014-05-15T23:59:59.000Z

476

Dihedral symmetry of periodic chain: quantization and coherent states  

E-Print Network [OSTI]

Our previous work on quantum kinematics and coherent states over finite configuration spaces is extended: the configuration space is, as before, the cyclic group $Z_{n}$ of arbitrary order n=2,3,..., but as its symmetry group a larger group -- the non-Abelian dihedral group $D_{n}$ -- is taken. The corresponding group related coherent states are constructed and their overcompleteness proved. Our approach based on geometric symmetry can be used as a kinematic framework for matrix methods in quantum chemistry of ring molecules.

Luft, P; Tolar, J

2007-01-01T23:59:59.000Z

477

Mathieu Moonshine and symmetries of K3 sigma models  

E-Print Network [OSTI]

A recent observation by Eguchi, Ooguri and Tachikawa (EOT) suggests a relationship between the largest Mathieu group M24 and the elliptic genus of K3. This correspondence would be naturally explained by the existence of a non-linear sigma-model on K3 with the Mathieu group as its group of symmetries. However, all possible symmetry groups of K3 models have been recently classified and none of them contains M24. We review the evidence in favour of the EOT conjecture and discuss the open problems in its physical interpretation.

Roberto Volpato

2012-01-30T23:59:59.000Z

478

Charge symmetry breaking in n p --> d pi^0  

E-Print Network [OSTI]

The forward--backward asymmetry in n p --> d pi^0, which must be zero in the center-of-mass system if charge symmetry is respected, has been measured to be [17.2 +/- 8 (stat) +/- 5.5 (sys)] * 10^{-4}, at an incident neutron energy of 279.5 MeV. This charge symmetry breaking observable was extracted by fitting the data with GEANT-based simulations and is compared to recent chiral effective field theory calculations, with implications regarding the value of the u d quark mass difference.

A. K. Opper; E. Korkmaz; D. A. Hutcheon; R. Abegg; C. A. Davis; R. W. Finlay; P. W. Green; L. G. Greeniaus; D. V. Jordan; J. A. Niskanen; G. V. O'Rielly; T. A. Porcelli; S. D. Reitzner; P. L. Walden; S. Yen

2003-06-19T23:59:59.000Z

479

Considering relativistic symmetry as the first principle of quantum mechanics  

E-Print Network [OSTI]

On the basis of the relativistic symmetry of Minkowski space, we derive a Lorentz invariant equation for a spread electron. This equation slightly differs from the Dirac equation and includes additional terms originating from the spread of an electron. Further, we calculate the anomalous magnetic moment based on these terms. These calculations do not include any divergence; therefore, renormalization procedures are unnecessary. In addition, the relativistic symmetry existing among coordinate systems will provide a new prospect for the foundations of quantum mechanics like the measurement process.

T. Kawahara

2007-04-20T23:59:59.000Z

480

Equilibria and Instabilities of a Slinky: Discrete Model  

E-Print Network [OSTI]

The Slinky is a well-known example of a highly flexible helical spring, exhibiting large, geometrically nonlinear deformations from minimal applied forces. By considering it as a system of coils that act to resist axial, shearing, and rotational deformations, we develop a discretized model to predict the equilibrium configurations of a Slinky via the minimization of its potential energy. Careful consideration of the contact between coils enables this procedure to accurately describe the shape and stability of the Slinky under different modes of deformation. In addition, we provide simple geometric and material relations that describe a scaling of the general behavior of flexible, helical springs.

Douglas P. Holmes; Andy D. Borum; Billy F. Moore III; Raymond H. Plaut; David A. Dillard

2014-03-26T23:59:59.000Z

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


481

A discrete-event simulation model for seaport operations.  

SciTech Connect (OSTI)

Discrete-event simulation has been used to assess detailed processes at seaports. Seaport operations are labor-intensive and require extensive use of personnel and machinery. The ability to conduct seaport operations efficiently can be improved significantly through proper utilization of seaport assets. The simulation described has been written in MODSIM II and addresses seaport operations in the context of military mobility. The simulation allows for multiple cargo types as well as multiple ship types. The overall goal of the simulation has been to determine seaport throughput capability.

Nevins, M. R.; Macal, C. M.; Joines, J.; Decision and Information Sciences; Transportation Engineering Agency

1998-01-01T23:59:59.000Z

482

Distributed mean curvature on a discrete manifold for Regge calculus  

E-Print Network [OSTI]

The integrated mean curvature of a simplicial manifold is well understood in both Regge Calculus and Discrete Differential Geometry. However, a well motivated pointwise definition of curvature requires a careful choice of volume over which to uniformly distribute the local integrated curvature. We show that hybrid cells formed using both the simplicial lattice and its circumcentric dual emerge as a remarkably natural structure for the distribution of this local integrated curvature. These hybrid cells form a complete tessellation of the simplicial manifold, contain a geometric orthonormal basis, and are also shown to give a pointwise mean curvature with a natural interpretation as a fractional rate of change of the normal vector.

Rory Conboye; Warner A. Miller; Shannon Ray

2015-02-26T23:59:59.000Z

483

Magnus force in discrete and continuous two-dimensional superfluids  

SciTech Connect (OSTI)

Motion of vortices in two-dimensional superfluids in the classical limit is studied by solving the Gross-Pitaevskii equation numerically on a uniform lattice. We find that, in the presence of a superflow directed along one of the main lattice periods, vortices move with the superflow on fine lattices but perpendicular to it on coarse ones. We interpret this result as a transition from the full Magnus force in a Galilean-invariant limit to vanishing effective Magnus force in a discrete system, in agreement with the existing experiments on vortex motion in Josephson junction arrays.

Gecse, Z.; Khlebnikov, S. [Department of Physics, Purdue University, West Lafayette, Indiana 47907 (United States)

2005-08-01T23:59:59.000Z

484

Exploiting Matrix Symmetry to Improve FPGA-Accelerated Conjugate Gradient  

E-Print Network [OSTI]

the Conjugate Gradient (CG) method using an FPGA co-processor. As in previous approaches, our coExploiting Matrix Symmetry to Improve FPGA- Accelerated Conjugate Gradient Jason D. Bakos, Krishna, high- performance computing, sparse matrix vector multiply, conjugate gradient I. INTRODUCTION Linear

Bakos, Jason D.

485

Symmetry Breaking Regime in the Nonlinear Hartree Equation  

E-Print Network [OSTI]

prove that a minimizer \\Phi does not have the symmetry properties of the potential v for jgj strictly, sodium 23 11 Na, and lithium 7 3 Li, in which 10 3 to 10 6 atoms have been confined in magnetic traps is the number of bosons in the system, v is the external potential (trap), and V is the two­body interaction

486

A Symmetry Approach to Geometric Phase for Quantum Ensembles  

E-Print Network [OSTI]

We use tools from the theory of dynamical systems with symmetries to stratify Uhlmann's standard purification bundle, and derive a connection for mixed quantum states. This connection gives rise to the geometric phase of Sj\\"{o}qvist-Tong et al. [PRL 85 2845 - 2849, PRL 93 080405].

Ole Andersson; Hoshang Heydari

2014-11-03T23:59:59.000Z

487

Hidden symmetries enhance quantum transport in Light Harvesting systems  

E-Print Network [OSTI]

For more than 50 years we have known that photosynthetic systems harvest solar energy with almost unit {\\it quantum efficiency}. However, recent experimental evidence of {\\it quantum coherence} during the excitonic energy transport in photosynthetic organisms challenges our understanding of this fundamental biological function. Currently, and despite numerous efforts, the causal connection between coherence and efficiency is still a matter of debate. We show, through the study of extensive simulations of quantum coherent transport on networks, that three dimensional structures characterized by centro-symmetric Hamiltonians are statistically more efficient than random arrangements. Moreover, we demonstrate that the experimental data available for the electronic Hamiltonians of the Fenna-Mathew-Olson (FMO) complex of sulfur bacteria and of the crypophyte PC645 complex of marine algae are consistent with this strong correlation of centro-symmetry with quantum efficiency. These results show that what appears to be geometrically disordered complexes may well exhibit a hidden symmetry which enhances the energy transport between chromophores. We are confident that our results will motivate research to explore the properties of nearly centro-symmetric Hamiltonians in more realistic environments, and to unveil the role of symmetries for quantum effects in biology. The unravelling of such symmetries may open novel perspectives and suggest new design principles in the development of artificial devices.

Tobias Zech; Roberto Mulet; Thomas Wellens; Andreas Buchleitner

2012-05-23T23:59:59.000Z

488

Generating conjecture and Einstein-Maxwell field of plane symmetry  

E-Print Network [OSTI]

For the plane symmetry we have found the electro-vacuum exact solutions of the Einstein-Maxwell equations and we have shown that one of them is equivalent to the McVittie solution of a charged infinite thin plane. The analytical extension has been accomplished and the Penrose conformal diagram has been obtained as well.

J. Fikar; J. Horsky

2000-04-10T23:59:59.000Z

489

The Einstein-Vlasov-Maxwell(EVM) System with Spherical Symmetry  

E-Print Network [OSTI]

We look for the global in time solution of the Cauchy problem corresponding to the asymptotically flat spherically symmetric EVM system with small initial data. Using an estimate, we also prove that if solution of the system stated above develops a singularity at all time, then the first one has to appear at the center of symmetry.

P. Noundjeu

2005-05-23T23:59:59.000Z

490

Localisation of Galilean symmetry and Horava-Lifshitz gravity  

E-Print Network [OSTI]

We derive the projectable version of Horava-Lifshitz gravity from the localisation of the Galilean symmetry. Specifically we provide a dynamical realisation of the metric that reproduces the transformations of the physical variables - lapse, shift and spatial component of the metric. Also, the measure defining the action is reproduced. The connection of Newton's gravity with Horava-Lifshitz gravity is elucidated.

Banerjee, Rabin

2015-01-01T23:59:59.000Z

491

Surface and Symmetry Energy Effects in Nuclear Multifragmentation  

SciTech Connect (OSTI)

It has been shown that the symmetry energy and the surface energy of hot fragments at the low-density freeze-out can be considerably modified. The influence of these changes on fragment yields and isotope distributions is discussed by analyzing recent ALADIN experimental data on spectator fragmentation at incident energy 600 A MeV.

Ogul, R. [Department of Physics, Selcuk University, 42079 Kampus, Konya (Turkey); Gesellschaft fuer Schwerionenforschung, D-64291 Darmstadt (Germany); Atav, U.; Buyukcizmeci, N. [Department of Physics, Selcuk University, 42079 Kampus, Konya (Turkey); Bianchin, S.; Napoli, M. de; Le Fevre, A.; Schwarz, C.; Sfienti, C.; Trautmann, W. [Gesellschaft fuer Schwerionenforschung, D-64291 Darmstadt (Germany); Botvina, A. S. [Gesellschaft fuer Schwerionenforschung, D-64291 Darmstadt (Germany); Institute for Nuclear Research, Russian Academy of Sciences, 117312 Moscow (Russian Federation); Lukasik, J. [Gesellschaft fuer Schwerionenforschung, D-64291 Darmstadt (Germany); NINP, Krakow (Poland); Mishustin, I. N. [FIAS, J.W. Goethe University, D-60438 Frankfurt am Main (Germany); Kurchatov Institute, Russian Research Center, 123182 Moscow (Russian Federation)

2009-01-28T23:59:59.000Z

492

Mechanisms of cellular symmetry breaking in S. cerevisiae  

E-Print Network [OSTI]

………………… … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … …..1 Chapter 2: Non ?uniform membrane diffusion enables steady?state cell polarization via vesicular trafficking………………………… … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … …..34 Chapter 3: Independence of symmetry breaking on... Bem1?mediated autocatalytic activation of Cdc42……………………… … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … ….88 Chapter 4: Preliminary data on Cdc42 microdomains in the presence of Rdi1 feedback………..135 Chapter 5...

Smith, Sarah Ellen

2013-12-31T23:59:59.000Z

493

Nuclear Symmetry Energy in Relativistic Mean Field Theory  

E-Print Network [OSTI]

The Physical origin of the nuclear symmetry energy is studied within the relativistic mean field (RMF) theory. Based on the nuclear binding energies calculated with and without mean isovector potential for several isobaric chains we conform earlier Skyrme-Hartree-Fock result that the nuclear symmetry energy strength depends on the mean level spacing $\\epsilon (A)$ and an effective mean isovector potential strength $\\kappa (A)$. A detaied analysis of isospin dependence of the two components contributing to the nuclear symmetry energy reveals a quadratic dependence due to the mean-isoscalar potential, $\\sim\\epsilon T^2$, and, completely unexpectedly, the presence of a strong linear component $\\sim\\kappa T(T+1+\\epsilon/\\kappa)$ in the isovector potential. The latter generates a nuclear symmetry energy in RMF theory that is proportional to $E_{sym}\\sim T(T+1)$ at variance to the non-relativistic calculation. The origin of the linear term in RMF theory needs to be further explored.

Shufang Ban; Jie Meng; Wojciech Satula; Ramon A. Wyss

2005-09-12T23:59:59.000Z

494

Symmetry energy in the structure and in reactions  

E-Print Network [OSTI]

Efforts to extract information on magnitude and density dependence of the nuclear symmetry energy are discussed. The utilized data include those on mass dependence of the excitation energies to the isobaric analog states of ground states, as well as data on the diffusion of isospin in heavy-ion reactions. Results following from different observables are compared.

P. Danielewicz

2010-03-21T23:59:59.000Z

495

Symmetry energy in the structure and in reactions  

E-Print Network [OSTI]

Efforts to extract information on magnitude and density dependence of the nuclear symmetry energy are discussed. The utilized data include those on mass dependence of the excitation energies to the isobaric analog states of ground states, as well as data on the diffusion of isospin in heavy-ion reactions. Results following from different observables are compared.

Danielewicz, P

2010-01-01T23:59:59.000Z

496

Static Solutions of Einstein's Equations with Spherical Symmetry  

E-Print Network [OSTI]

The Schwarzschild solution is a complete solution of Einstein's field equations for a static spherically symmetric field. The Einstein's field equations solutions appear in the literature, but in different ways corresponding to different definitions of the radial coordinate. We attempt to compare them to the solutions with nonvanishing energy density and pressure. We also calculate some special cases with changes in spherical symmetry.

Iftikhar Ahmad; Maqsoom Fatima; Najam-ul-Basat

2014-05-02T23:59:59.000Z

497

Addendum: Symmetries of the energy-momentum tensor  

E-Print Network [OSTI]

In recent papers [1-3], we have discussed matter symmetries of non-static spherically symmetric spacetimes, static plane symmetric spacetimes and cylindrically symmetric static spacetimes. These have been classified for both cases when the energy-momentum tensor is non-degenerate and also when it is degenerate. Here we add up some consequences and the missing references about the Ricci tensor.

M. Sharif

2004-10-28T23:59:59.000Z

498

Hidden Symmetry Unmasked: Matrix Theory and E(11)  

E-Print Network [OSTI]

Dimensional reduction of eleven-dimensional supergravity to zero spacetime dimensions is expected to give a theory characterized by the hidden symmetry algebra E(11), the end-point of the Cremmer-Julia prediction for the sequence of dimensional reductions of 11d supergravity to spacetime dimensions. In recent work, we have given a prescription for the spacetime reduction of a supergravity-Yang-Mills Lagrangian with large N flavor symmetry such that the local symmetries of the continuum Lagrangian are preserved in the resulting reduced matrix Lagrangian. This new class of reduced matrix models are the basis for a nonperturbative proposal for M theory we have described in hep-th/0408057. The matrix models are also characterized by hidden symmetry algebras in precise analogy with the Cremmer-Julia framework. The rank eleven algebra E(11) is also known as the very-extension of the finite-dimensional Lie algebra E(8). In an independent stream of work (hep-th/0402140), Peter West has provided evidence which supports the conjecture that M theory has the symmetry algebra E(11), showing that it successfully incorporates both the 11d supergravity limit, as well as the 10d type IIA and type IIB supergravities, and inclusive of the full spectrum of Neveu-Schwarz and Dirichlet pbranes. In this topical review, we give a pedagogical account of these recent developments also providing an assessment of the insights that might be gained from linking the algebraic and reduced matrix model perspectives in the search for M theory. Necessary mathematical details are covered starting from the basics in the appendices.

Shyamoli Chaudhuri

2004-08-08T23:59:59.000Z

499

A Method for Treating Discretization Error in Nondeterministic Analysis  

SciTech Connect (OSTI)

A response surface methodology-based technique is presented for treating discretization error in non-deterministic analysis. The response surface, or metamodel, is estimated from computer experiments which vary both uncertain physical parameters and the fidelity of the computational mesh. The resultant metamodel is then used to propagate the variabilities in the continuous input parameters, while the mesh size is taken to zero, its asymptotic limit. With respect to mesh size, the metamodel is equivalent to Richardson extrapolation, in which solutions on coarser and finer meshes are used to estimate discretization error. The method is demonstrated on a one dimensional prismatic bar, in which uncertainty in the third vibration frequency is estimated by propagating variations in material modulus, density, and bar length. The results demonstrate the efficiency of the method for combining non-deterministic analysis with error estimation to obtain estimates of total simulation uncertainty. The results also show the relative sensitivity of failure estimates to solution bias errors in a reliability analysis, particularly when the physical variability of the system is low.

Alvin, K.F.

1999-01-27T23:59:59.000Z

500

Light clusters production as a probe to nuclear symmetry energy RID A-2398-2009  

E-Print Network [OSTI]

the yields and the energy spectra of these light clusters are affected significantly by the density dependence of nuclear symmetry energy, with a stiffer symmetry energy giving a larger yield....

Chen, LW; Ko, Che Ming; Li, Ba.

2003-01-01T23:59:59.000Z