Vacuum space-times with controlled singularities and without symmetries
Piotr T. Chru?ciel; Paul Klinger
2015-07-01
We present a family of four-dimensional vacuum space-times with asymptotically velocity dominated singularities and without symmetries.
Continuous space-time symmetries in a lattice field theory
H. B. Thacker
1998-09-18
For purposes of regularization as well as numerical simulation, the discretization of Lorentz invariant continuum field theories on a space-time lattice is often convenient. In general, this discretization destroys the rotational or Lorentz-frame independence of the theory, which is only recovered in the continuum limit. The Baxter 8-vertex model may be interpreted as a particular discretization of a self-interacting massive Dirac fermion theory in two dimensions (the massive Thirring model). Here it is shown that, in the 8-vertex/massive Thirring model, the Lorentz frame independence of the theory remains undisturbed on the lattice. The only effect of the discretization is to compactify the manifold of Lorentz frames. The relationship between this lattice Lorentz symmetry and the Yang-Baxter relations is discussed.
Space-time as a discrete field noncommutative causal network
G. L. Stavraki
2009-07-02
The necessity of rejecting the numerical model of geometrical extension is postulated on the basis of the idea of identity of space-time and physical vacuum. An attempt is made to define space-time not via the concept of manifold, but via the store of physical functions defined on it. The new description is based on the commutator representation of the causal structure of operator field theory. It is not the world point, but a universal field supermatrix complex U that is assumed to be the carrier of possible local events. This complex involves a complete set of Heisenberg local field operators together with their spin-group bases in the Fermi-field representation. The fundamental element of the extension is described in the model by the equation of a special commutator algebra closed on two such local complexes U_1 and U_2 "nearest" in the two-sided light-like connection and linked by a single virtual field interaction vertex. The discrete character of the constructed "quantum proximity" equation containing the gravitational constant is associated with the existence of local curvature on the Planck scale. Algebraic closed-ness of the basic equation suggests that the charge symmetry group should be group E_6 with non-standard representations of the fermion and scalar fields. On the basis of the calculated U expression we propose an effective superinvariant Lagrangian with fixed coefficients on the near-Planck scale, from which one can in principle try to obtain a low-energy limit for comparison with the real world.
Physics in discrete spaces (A): Space-Time organization
P. Peretto
2010-12-29
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.
Is space-time symmetry a suitable generalization of parity-time symmetry?
Amore, Paolo; Fernández, Francisco M.; Garcia, Javier
2014-11-15
We discuss space-time symmetric Hamiltonian operators of the form H=H{sub 0}+igH{sup ?}, where H{sub 0} is Hermitian and g real. H{sub 0} is invariant under the unitary operations of a point group G while H{sup ?} is invariant under transformation by elements of a subgroup G{sup ?} of G. If G exhibits irreducible representations of dimension greater than unity, then it is possible that H has complex eigenvalues for sufficiently small nonzero values of g. In the particular case that H is parity-time symmetric then it appears to exhibit real eigenvalues for all 0
Discrete R Symmetries and Low Energy Supersymmetry
California at Santa Cruz, University of
R Symmetries and Low Energy Supersymmetry #12;Plan for Today: "New, Improved" Models of DynamicalDiscrete R Symmetries and Low Energy Supersymmetry UC Davis, 2011 Michael Dine Department on metastable susy breaking. Michael Dine Discrete R Symmetries and Low Energy Supersymmetry #12;Metastable
On Energy Distribution of Two Space-times with Planar and Cylindrical Symmetries
Saeed Mirshekari; Amir M. Abbassi
2014-11-29
Considering encouraging Virbhadra's results about energy distribution of non-static spherically symmetric metrics in Kerr-Schild class, it would be interesting to study some space-times with other symmetries. Using different energy-momentum complexes, i.e. M{\\o}ller, Einstein, and Tolman, in static plane-symmetric and cylindrically symmetric solutions of Einstein-Maxwell equations in 3+1 dimensions, energy (due to matter and fields including gravity) distribution is studied. Energy expressions are obtained finite and well-defined. calculations show interesting coincidences between the results obtained by Einstein and Tolamn prescriptions. Our results support the Cooperstock hypothesis about localized energy.
Higgs-like Mechanism for Spontaneous Space-time Symmetry Breaking
Kimihide Nishimura
2015-06-28
The study of spontaneous breakdown of space-time symmetries discovers another type of Higgs mechanism operating in a chiral SU(2) model. Part of Nambu-Goldstone vector mesons emergent from simultaneous violations of gauge and Lorentz symmetries are in this case absorbed by a left-handed doublet and endow one of the fermions with a right-handed state, while another part becomes emergent photons. Accordingly, this mechanism allows a chiral fermion to acquire a mass, and enables the emergent theory to reproduce the electromagnetism equivalent to the QED sector of the standard theory. It is also mentioned that the "Fermion-Boson puzzle" reported in the presence of a 't Hooft-Polyakov monopole does not exist in our theory.
Internal Space-time Symmetries of Particles derivable from Periodic Systems in Optics
Y. S. Kim
2010-09-26
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.
Quantization of Point Particles in 2+1 Dimensional Gravity and Space-Time Discreteness
G. 't Hooft
1996-01-10
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.
Paris-Sud XI, Université de
, allocation function, space-time complexity, re-indexation 1 Introduction The Cholesky Factorization (CF allocation methods and their application to CF. Second, stemming from a new allocation method we derive design improves the best previously known bound, N2/6 + (N), induced by previous allocation methods
Symmetries In Evolving Space-time and Their Connection To High-frequency Gravity Wave Production
A. W. Beckwith
2008-04-01
We present how a worm hole bridge from a prior to the present universe allows us to use symmetry arguments which allow us to generate relic gravity waves, and also non massless gravitons. The relic gravitons are produced due to thermal / vacuum energy transferral from a prior universe using a pseudo time dependent version of the Wheeler De Witt equation as presented by Crowell (2005)
Leptonic Dirac CP Violation Predictions from Residual Discrete Symmetries
Girardi, I; Stuart, Alexander J; Titov, A V
2015-01-01
Assuming that the observed pattern of 3-neutrino mixing is related to the existence of a (lepton) flavour symmetry, corresponding to a non-Abelian discrete symmetry group $G_f$, and that $G_f$ is broken to specific residual symmetries $G_e$ and $G_\
Leptonic Dirac CP Violation Predictions from Residual Discrete Symmetries
I. Girardi; S. T. Petcov; Alexander J. Stuart; A. V. Titov
2015-09-08
Assuming that the observed pattern of 3-neutrino mixing is related to the existence of a (lepton) flavour symmetry, corresponding to a non-Abelian discrete symmetry group $G_f$, and that $G_f$ is broken to specific residual symmetries $G_e$ and $G_\
Signatures of discrete symmetries in the scalar sector
Lavoura, L. (Department of Physics, Carnegie-Mellon University, Pittsburgh, Pennsylvania 15213 (United States))
1994-12-01
I discuss methods to identify the presence of discrete symmetries in the two-Higgs-doublet model by observing the masses and the cubic and quartic interactions of the scalars. The symmetries considered are a [ital Z][sub 2] symmetry under which [phi][sub 2][r arrow][minus][phi][sub 2], and a [ital CP] symmetry which enforces real coupling constants in the Higgs potential. Those symmetries are spontaneously broken, and the [ital Z][sub 2] symmetry may also be softly broken. I identify the signatures in the interactions of the scalars that these symmetries leave after their breaking.
Leptons and Quarks from a Discrete Flavor Symmetry
Y. H. Ahn
2013-03-20
We propose a new model of leptons and quarks based on the discrete flavor symmetry $T'$, the double covering of $A_4$, in which the hierarchies of charged fermion masses and the mildness of neutrino masses are responsible for Higgs scalars. After spontaneous breaking of flavor symmetry, with the constraint of renormalizability in the Lagrangian, the leptons have $m_{e}=0$ and the quarks have the Cabibbo-Kobayashi-Maskawa (CKM) mixing angles $\\theta^{q}_{12}=13^{\\circ}, \\theta^{q}_{23}=0^{\\circ}$ and $\\theta^{q}_{13}=0^{\\circ}$. Thus, certain effective dimension-5 operators are introduced, which induce $m_{e}\
Semiclassical approach to discrete symmetries in quantum chaos
Joyner, Chris; Sieber, Martin
2012-01-01
We use semiclassical methods to evaluate the spectral two-point correlation function of quantum chaotic systems with discrete geometrical symmetries. The energy spectra of these systems can be divided into subspectra that are associated to irreducible representations of the corresponding symmetry group. We show that for (spinless) time reversal invariant systems the statistics inside these subspectra depend on the type of irreducible representation. For real representations the spectral statistics agree with those of the Gaussian Orthogonal Ensemble (GOE) of Random Matrix Theory (RMT), whereas complex representations correspond to the Gaussian Unitary Ensemble (GUE). For systems without time reversal invariance all subspectra show GUE statistics. There are no correlations between non-degenerate subspectra. Our techniques generalize recent developments in the semiclassical approach to quantum chaos allowing one to obtain full agreement with the two-point correlation function predicted by RMT, including oscilla...
Semiclassical approach to discrete symmetries in quantum chaos
Chris Joyner; Sebastian Müller; Martin Sieber
2012-02-22
We use semiclassical methods to evaluate the spectral two-point correlation function of quantum chaotic systems with discrete geometrical symmetries. The energy spectra of these systems can be divided into subspectra that are associated to irreducible representations of the corresponding symmetry group. We show that for (spinless) time reversal invariant systems the statistics inside these subspectra depend on the type of irreducible representation. For real representations the spectral statistics agree with those of the Gaussian Orthogonal Ensemble (GOE) of Random Matrix Theory (RMT), whereas complex representations correspond to the Gaussian Unitary Ensemble (GUE). For systems without time reversal invariance all subspectra show GUE statistics. There are no correlations between non-degenerate subspectra. Our techniques generalize recent developments in the semiclassical approach to quantum chaos allowing one to obtain full agreement with the two-point correlation function predicted by RMT, including oscillatory contributions.
Breaking discrete symmetries in the effective field theory of inflation
Dario Cannone; Jinn-Ouk Gong; Gianmassimo Tasinato
2015-05-29
We study the phenomenon of discrete symmetry breaking during the inflationary epoch, using a model-independent approach based on the effective field theory of inflation. We work in a context where both time reparameterization symmetry and spatial diffeomorphism invariance can be broken during inflation. We determine the leading derivative operators in the quadratic action for fluctuations that break parity and time-reversal. Within suitable approximations, we study their consequences for the dynamics of linearized fluctuations. Both in the scalar and tensor sectors, we show that such operators can lead to new direction-dependent phases for the modes involved. They do not affect the power spectra, but can have consequences for higher correlation functions. Moreover, a small quadrupole contribution to the sound speed can be generated.
Fatemeh Bagheri; Reza Mansouri
2014-08-03
Applying the method of conformal metric to a given static axially symmetric vacuum solution of the Einstein equations, we have shown that there is no solution representing a cosmic ideal fluid which is asymtotically FLRW. Letting the cosmic fluid to be imperfect there are axially symmetric solutions tending to FLRW at space infinity. The solution we have found represents an axially symmetric spacetime leading to a spherically symmetric Einstein tensor. Therefore, we have found a solution of Einstein equations representing a spherically symmetric matter distribution corresponding to a spacetime which does not reflect the same symmetry. We have also found another solution of Einstein equation corresponding to the same energy tensor with spherical symmetry.
Non-Abelian discrete gauge symmetries in F-theory
Grimm, Thomas W; Regalado, Diego
2015-01-01
The presence of non-Abelian discrete gauge symmetries in four-dimensional F-theory compactifications is investigated. Such symmetries are shown to arise from seven-brane configurations in genuine F-theory settings without a weak string coupling description. Gauge fields on mutually non-local seven-branes are argued to gauge both R-R and NS-NS two-form bulk axions. The gauging is completed into a generalisation of the Heisenberg group with either additional seven-brane gauge fields or R-R bulk gauge fields. The former case relies on having seven-brane fluxes, while the latter case requires torsion cohomology and is analysed in detail through the M-theory dual. Remarkably, the M-theory reduction yields an Abelian theory that becomes non-Abelian when translated into the correct duality frame to perform the F-theory limit. The reduction shows that the gauge coupling function depends on the gauged scalars and transforms non-trivially as required for the groups encountered. This field dependence agrees with the exp...
Non-Abelian discrete gauge symmetries in F-theory
Thomas W. Grimm; Tom G. Pugh; Diego Regalado
2015-04-23
The presence of non-Abelian discrete gauge symmetries in four-dimensional F-theory compactifications is investigated. Such symmetries are shown to arise from seven-brane configurations in genuine F-theory settings without a weak string coupling description. Gauge fields on mutually non-local seven-branes are argued to gauge both R-R and NS-NS two-form bulk axions. The gauging is completed into a generalisation of the Heisenberg group with either additional seven-brane gauge fields or R-R bulk gauge fields. The former case relies on having seven-brane fluxes, while the latter case requires torsion cohomology and is analysed in detail through the M-theory dual. Remarkably, the M-theory reduction yields an Abelian theory that becomes non-Abelian when translated into the correct duality frame to perform the F-theory limit. The reduction shows that the gauge coupling function depends on the gauged scalars and transforms non-trivially as required for the groups encountered. This field dependence agrees with the expectations for the kinetic mixing of seven-branes and is unchanged if the gaugings are absent.
The Kink variety in systems of two coupled scalar fields in two space-time dimensions
A. Alonso Izquierdo; M. A. Gonzalez Leon; J. Mateos Guilarte
2002-01-25
In this paper we describe the moduli space of kinks in a class of systems of two coupled real scalar fields in (1+1) Minkowskian space-time. The main feature of the class is the spontaneous breaking of a discrete symmetry of (real) Ginzburg-Landau type that guarantees the existence of kink topological defects.
Lepton Mixing Predictions from (Generalised) CP and Discrete Flavour Symmetry
Thomas Neder
2015-03-31
An important class of flavour groups, that are subgroups of $U(3)$ and that predict experimentally viable lepton mixing parameters including Majorana phases, is the $\\Delta(6n^2)$ series. The most well-known member is $\\Delta(24)=S_4$. I present results of several extensive studies of lepton mixing predictions obtained in models with a $\\Delta(6n^2)$ flavour group that preserve either the full residual $Z_2\\times Z_2$ or a $Z_2$ subgroup for neutrinos and can include a generalised CP symmetry. Predictions include mixing angles and Dirac CP phase generally; and if invariance under a generalised CP symmetry is included, also Majorana phases. For this, the interplay of flavour group and generalised CP symmetry has to be studied carefully.
Fermions in odd space-time dimensions: back to basics
Bashir, A; Galicia, Ma. de Jesus Anguiano
2005-01-01
It is a well known feature of odd space-time dimensions $d$ that there exist two inequivalent fundamental representations $A$ and $B$ of the Dirac gamma matrices. Moreover, the parity transformation swaps the fermion fields living in $A$ and $B$. As a consequence, a parity invariant Lagrangian can only be constructed by incorporating both the representations. Based upon these ideas and contrary to long held belief, we show that in addition to a discrete exchange symmetry for the massless case, we can also define chiral symmetry provided the Lagrangian contains fields corresponding to both the inequivalent representations. We also study the transformation properties of the corresponding chiral currents under parity and charge conjugation operations. We work explicitly in 2+1 dimensions and later show how some of these ideas generalize to an arbitrary number of odd dimensions.
Fermions in odd space-time dimensions: back to basics
A. Bashir; Ma. de Jesus Anguiano Galicia
2005-02-09
It is a well known feature of odd space-time dimensions $d$ that there exist two inequivalent fundamental representations $A$ and $B$ of the Dirac gamma matrices. Moreover, the parity transformation swaps the fermion fields living in $A$ and $B$. As a consequence, a parity invariant Lagrangian can only be constructed by incorporating both the representations. Based upon these ideas and contrary to long held belief, we show that in addition to a discrete exchange symmetry for the massless case, we can also define chiral symmetry provided the Lagrangian contains fields corresponding to both the inequivalent representations. We also study the transformation properties of the corresponding chiral currents under parity and charge conjugation operations. We work explicitly in 2+1 dimensions and later show how some of these ideas generalize to an arbitrary number of odd dimensions.
Discrete flavour symmetries for degenerate solar neutrino pair and their predictions
Anjan S. Joshipura; Ketan M. Patel
2014-05-23
Flavour symmetries appropriate for describing a neutrino spectrum with degenerate solar pair and a third massive or massless neutrino are discussed. We demand that the required residual symmetries of the leptonic mass matrices be subgroups of some discrete symmetry group $G_f$. $G_f$ can be a subgroup of SU(3) if the third neutrino is massive and we derive general results on the mixing angle predictions for various discrete subgroups of SU(3). The main results are: (a) All the SU(3) subgroups of type C fail in simultaneously giving correct $\\theta_{13}$ and $\\theta_{23}$. (b) All the groups of type D can predict a relation $\\cos^2\\theta_{13} \\sin^2\\theta_{23}=\\frac{1}{3}$ among the mixing angles which appears to be a good zeroth order approximation. Among these, various $\\Delta(6n^2)$ groups with $n\\geq 8$ can simultaneously lead also to $\\sin^2 \\theta_{13}$ in agreement with global fit at 3$\\sigma$. (c) The group $\\Sigma(168)\\cong PSL(2,7)$ predicts near to the best fit value for $\\theta_{13}$ and $\\theta_{23}$ within the 1$\\sigma$ range. All discrete subgroups of U(3) with order $predict $\\theta_{13}$ and/or $\\theta_{23}$. The solar angle remains undetermined at the leading order in all the cases due to degeneracy in the masses. A class of general perturbations which can correctly reproduce all the observables are discussed in the context of several groups which offer good leading order predictions.
Daiqin Su; T. C. Ralph
2015-07-02
We show that the particle number distribution of diamond modes, modes that are localised in a finite space-time region, are thermal for the Minkowski vacuum state of a massless scalar field, an analogue to the Unruh effect. The temperature of the diamond is inversely proportional to its size. An inertial observer can detect this thermal radiation by coupling to the diamond modes using an appropriate energy scaled detector. We further investigate the correlations between various diamonds and find that entanglement between adjacent diamonds dominates.
A Vector-Like Fourth Generation with A Discrete Symmetry From Split-UED
Kong, Kyoungchul; /SLAC; Park, Seong Chan; /Tokyo U., IPMU; Rizzo, Thomas G.; /SLAC
2011-08-19
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.
Discrete accidental symmetry for a particle in a constant magnetic field on a torus
Al-Hashimi, M.H. Wiese, U.-J.
2009-02-15
A classical particle in a constant magnetic field undergoes cyclotron motion on a circular orbit. At the quantum level, the fact that all classical orbits are closed gives rise to degeneracies in the spectrum. It is well-known that the spectrum of a charged particle in a constant magnetic field consists of infinitely degenerate Landau levels. Just as for the 1/r and r{sup 2} potentials, one thus expects some hidden accidental symmetry, in this case with infinite-dimensional representations. Indeed, the position of the center of the cyclotron circle plays the role of a Runge-Lenz vector. After identifying the corresponding accidental symmetry algebra, we re-analyze the system in a finite periodic volume. Interestingly, similar to the quantum mechanical breaking of CP invariance due to the {theta}-vacuum angle in non-Abelian gauge theories, quantum effects due to two self-adjoint extension parameters {theta}{sub x} and {theta}{sub y} explicitly break the continuous translation invariance of the classical theory. This reduces the symmetry to a discrete magnetic translation group and leads to finite degeneracy. Similar to a particle moving on a cone, a particle in a constant magnetic field shows a very peculiar realization of accidental symmetry in quantum mechanics.
Metastring Theory and Modular Space-time
Laurent Freidel; Robert G. Leigh; Djordje Minic
2015-02-27
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.
Space-time attributes of physical objects and the laws of space-time physics
J. H. Field
2008-09-24
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.
Zuelicke, U
2012-01-01
The most fundamental characteristics of a physical system can often be deduced from its behaviour under discrete symmetry transformations such as time reversal, parity and chirality. Here we review basic symmetry properties of the relativistic quantum theories for free electrons in (2+1)- and (1+1)-dimensional spacetime. Additional flavour degrees of freedom are necessary to properly define symmetry operations in (2+1) dimensions and are generally present in physical realisations of such systems, e.g., in single sheets of graphite. We find that there exist two possibilities for defining any flavour-coupling discrete symmetry operation of the two-flavour (2+1)-dimensional Dirac theory. Physical implications of this duplicity are discussed.
Space-Time Galerkin Projection of Electro-Magnetic Fields
Wang, Zifu; Hofmann, Heath
2015-01-01
Spatial Galerkin projection transfers fields between different meshes. In the area of finite element analysis of electromagnetic fields, it provides great convenience for remeshing, multi-physics, domain decomposition methods, etc. In this paper, a space-time Galerkin projection is developed in order to transfer fields between different spatial and temporal discretization bases.
Space-time Curvature of Classical Electromagnetism
R. W. M. Woodside
2004-10-08
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.
Ning Wu
2012-07-11
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.
Hyperbolic statics in space-time
Dmitry Pavlov; Sergey Kokarev
2014-12-11
Based on the concept of material event as an elementary material source that is concentrated on metric sphere of zero radius --- light-cone of Minkowski space-time, we deduce the analog of Coulomb's law for hyperbolic space-time field universally acting between the events of space-time. Collective field that enables interaction of world lines of a pair of particles at rest contains a standard 3-dimensional Coulomb's part and logarithmic addendum. We've found that the Coulomb's part depends on a fine balance between causal and geometric space-time characteristics (the two regularizations concordance).
Convergence of Space-Time Discrete Dynamics to Anisotropic ...
2014-10-31
Oct 31, 2014 ... is a typical model for the motion of materials phase boundaries. ... of W. The function u also makes a smooth but rapid transition with thickness ...
Brodsky, Stanley J.; /SLAC; Gardner, Susan; /Kentucky U.; Hwang, Dae Sung; /Sejong U.
2006-01-11
We consider the electric dipole form factor, F{sub 3}(q{sup 2}), as well as the Dirac and Pauli form factors, F{sub 1}(q{sup 2}) and F{sub 2}(q{sup 2}), of the nucleon in the light-front formalism. We derive an exact formula for F{sub 3}(q{sup 2}) to complement those known for F{sub 1}(q{sup 2}) and F{sub 2}(q{sup 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{sub 2}(q{sup 2}) and F{sub 3}(q{sup 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}{sup n} {approx} -{kappa}{sup p}.
Brodsky, Stanley J. [Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States); Gardner, Susan [Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506-0055 (United States); Hwang, Dae Sung [Department of Physics, Sejong University, Seoul 143-747 (Korea, Republic of)
2006-02-01
We consider the electric dipole form factor, F{sub 3}(q{sup 2}), as well as the Dirac and Pauli form factors, F{sub 1}(q{sup 2}) and F{sub 2}(q{sup 2}), of the nucleon in the light-front formalism. We derive an exact formula for F{sub 3}(q{sup 2}) to complement those known for F{sub 1}(q{sup 2}) and F{sub 2}(q{sup 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{sub 2}(q{sup 2}) and F{sub 3}(q{sup 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}{sup n}{approx}-{kappa}{sup p}.
S. J. Brodsky; S. Gardner; D. S. Hwang
2006-02-27
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.
Brodsky, S J; Hwang, D S
2006-01-01
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 ...
Gravity in Complex Hermitian Space-Time
Ali H. Chamseddine
2006-10-09
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.
How current loops and solenoids curve space-time
A. Füzfa
2015-04-01
The curved space-time around current loops and solenoids carrying arbitrarily large steady electric currents is obtained from the numerical resolution of the coupled Einstein-Maxwell equations in cylindrical symmetry. The artificial gravitational field associated to the generation of a magnetic field produces gravitational redshift of photons and gravitational acceleration of neutral massive particles. The strength of the generated gravitational field is extremely weak from what can be obtained through present technology, although it might be detectable with high-precision measurements such as atom interferometry.
Lorentz symmetry for 3d Quantum Cellular Automata
Alessandro Bisio; Giacomo Mauro D'Ariano; Paolo Perinotti
2015-03-03
We introduce a definition of Lorentz transformations in the framework of quantum cellular automata. Our definition does not require space-time, and retains the usual interpretation in the emergent one. The definition is group theoretical, with flatness of space-time corresponding to Abelianity of the cellular automaton group. We consider the covariance in the case of the Weyl automaton. The notion of particle as Poincar\\'e irreducible representation survives at all scales. The interpolation of the Lorentz symmetry from the discrete to the continuum scale occurs through a nonlinear representation. We also discuss the connection of the nonlinear Lorentz transformations with the Poincar\\'e and k-Poincar\\'e Hopf algebra, the emerging non-commutative space-time, and the deformed Heisenberg commutation relations.
On time-reversal and space-time harmonic processes for Markovian quantum channels
Francesco Ticozzi; Michele Pavon
2009-04-29
The time reversal of a completely-positive, nonequilibrium discrete-time quantum Markov evolution is derived via a suitable adjointness relation. Space-time harmonic processes are introduced for the forward and reverse-time transition mechanisms, and their role for relative entropy dynamics is discussed.
Eigenfunction Expansion of the Space-Time Dependent Neutron Survival...
Office of Scientific and Technical Information (OSTI)
Eigenfunction Expansion of the Space-Time Dependent Neutron Survival Probability. Citation Details In-Document Search Title: Eigenfunction Expansion of the Space-Time Dependent...
Quantum singularities in static and conformally static space-times
D. A. Konkowski; T. M. Helliwell
2011-12-22
The definition of quantum singularity is extended from static space-times to conformally static space-times. After the usual definitions of classical and quantum singularities are reviewed, examples of quantum singularities in static space-times are given. These include asymptotically power-law space-times, space-times with diverging higher-order differential invariants, and a space-time with a 2-sphere singularity. The theory behind quantum singularities in conformally static space-times is followed by an example, a Friedmann-Robertson-Walker space-time with cosmic string. The paper concludes by discussing areas of future research.
Discrimination of particle masses in multivariant space-time geometry
Yuri A. Rylov
2007-12-11
Multivariance of geometry means that at the point $P_{0}$ there exist many vectors $P_{0}P_{1}$, $\\P_{0}P_{2}$,... which are equivalent (equal) to the vector $\\Q_{0}Q_{1}$ at the point $Q_{0}$, but they are not equivalent between themselves. The discrimination capacity (zero-variance) of geometry appears, when at the point $P_{0}$ there are no vectors, which are equivalent to the vector $Q_{0}Q_{1}$ at the point $Q_{0}$. It is shown, that in some multivariant space-time geometries some particles of small mass may be discriminated (i.e. either they do not exist, or their evolution is impossible). The possibility of some particle discrimination may appear to be important for explanation of the discrete character of mass spectrum of elementary particles.
Y. M. Cho
2007-03-02
We present a topological classification of vacuum space-time. Assuming the 3-dimensional space allows a global chart, we show that the static vacuum space-time of Einstein's theory can be classified by the knot topology $\\pi_3(S^3)=\\pi_3(S^2)$. Viewing Einstein's theory as a gauge theory of Lorentz group and identifying the gravitational connection as the gauge potential of Lorentz group, we construct all possible vacuum gravitational connections which give a vanishing curvature tensor. With this we show that the vacuum connection has the knot topology, the same topology which describes the multiple vacua of SU(2) gauge theory. We discuss the physical implications of our result in quantum gravity.
Modern space-time and undecidability
Rodolfo Gambini; Jorge Pullin
2008-01-16
The picture of space-time that Minkowski created in 1907 has been followed by two important developments in physics not contained in the original picture: general relativity and quantum mechanics. We will argue that the use of concepts of those theories to construct space-time implies conceptual modifications in quantum mechanics. In particular one can construct a viable picture of quantum mechanics without a reduction process that has outcomes equivalent to a picture with a reduction process. One therefore has two theories that are entirely equivalent experimentally but profoundly different in the description of reality they give. This introduces a fundamental level of undecidability in physics of a kind that has not been present before. We discuss some of the implications.
Alexander N. Jourjine
2010-03-12
We develop further the formalism of the non-Abelian gauge field theory on a cell complex space-time and show how the gauge-invariant action and the equations of motion for gauge fields interacting with spinors can be written without a reference to the geometrical nature of the cells of the cell complex. The general results are illustrated with examples of solutions of equations of motion for U(N) and SU(N) gauge groups.
Nature Itself in a Mirror Space-Time
Rasulkhozha S. Sharafiddinov
2015-10-12
The unity of the structure of matter fields with flavor symmetry laws involves that the left-handed neutrino in the field of emission can be converted into a right-handed one and vice versa. These transitions together with classical solutions of the Dirac equation testify in favor of the unidenticality of masses, energies, and momenta of neutrinos of the different components. If we recognize such a difference in masses, energies, and momenta, accepting its ideas about that the left-handed neutrino and the right-handed antineutrino refer to long-lived leptons, and the right-handed neutrino and the left-handed antineutrino are short-lived fermions, we would follow the mathematical logic of the Dirac equation in the presence of the flavor symmetrical mass, energy, and momentum matrices. From their point of view, nature itself separates Minkowski space into left and right spaces concerning a certain middle dynamical line. Thereby, it characterizes any Dirac particle both by left and by right space-time coordinates. It is not excluded therefore that whatever the main purposes each of earlier experiments about sterile neutrinos, namely, about right-handed short-lived neutrinos may serve as the source of facts confirming the existence of a mirror Minkowski space-time.
Holographic Space-time and Newton's Law
Tom Banks; Willy Fischler
2013-10-25
We derive Newton's Law from the formalism of Holographic Space-Time (HST). More precisely, we show that for a large class of Hamiltonians of the type proposed previously for the HST description of a geodesic in Minkowski space, the eikonal for scattering of two massless particles at large impact parameter scales as expected with the impact parameter and the energies of the particles in the center of mass (CM) frame. We also discuss the criteria for black hole production in this collision, and find an estimate, purely within the HST framework, for the impact parameter at which it sets in, which coincides with the estimate based on general relativity.
Fermion Fields in BTZ Black Hole Space-Time and Entanglement Entropy
Dharm Veer Singh; Sanjay Siwach
2015-08-07
We study the entanglement entropy of fermion fields in BTZ black hole space-time and calculate pre- factor of the leading and sub-leading terms and logarithmic divergence term of the entropy using the discretized model. The leading term is the standard Bekenstein-Hawking area law and sub-leading term corresponds to first quantum corrections in black hole entropy. We also investigate the corrections to entanglement entropy for massive fermion fields in BTZ space-time. The mass term does not affect the area law.
R. L. Oldershaw
2007-12-19
The possibility that global discrete dilation invariance is a fundamental symmetry principle of nature is explored. If the discrete self-similarity observed in nature is exact, then the Principle of General Covariance needs to be broadened in order to accommodate this form of discrete conformal invariance, and a further generalization of relativity theory is required.
Note on Discrete Gauge Anomalies
T. Banks; M. Dine
1991-10-02
We consider the probem of gauging discrete symmetries. All valid constraints on such symmetries can be understood in the low energy theory in terms of instantons. We note that string perturbation theory often exhibits global discrete symmetries, which are broken non-perturbatively.
Barrios, Nahuel; Pullin, Jorge
2015-01-01
We consider a massive scalar field living on the recently found exact quantum space-time corresponding to vacuum spherically symmetric loop quantum gravity. The discreteness of the quantum space time naturally regularizes the scalar field, eliminating divergences. However, the resulting finite theory depends on the details of the micro physics. We argue that such dependence can be eliminated through a finite renormalization and discuss its nature. This is an example of how quantum field theories on quantum space times deal with the issues of divergences in quantum field theories.
Naked strong curvature singularities in Szekeres space-times
Pankaj S. Joshi; Andrzej Krolak
1996-05-17
We investigate the occurrence and nature of naked singularities in the Szekeres space-times. These space-times represent irrotational dust. They do not have any Killing vectors and they are generalisations of the Tolman-Bondi-Lemaitre space-times. It is shown that in these space-times there exist naked singularities that satisfy both the limiting focusing condition and the strong limiting focusing condition. The implications of this result for the cosmic censorship hypothesis are discussed.
Space-Time as an Orderparameter Manifold in Random Networks and the Emergence of Physical Points
Manfred Requardt
1999-02-11
In the following we are going to describe how macroscopic space-time is supposed to emerge as an orderparameter manifold or superstructure floating in a stochastic discrete network structure. As in preceeding work (mentioned below), our analysis is based on the working philosophy that both physics and the corresponding mathematics have to be genuinely discrete on the primordial (Planck scale) level. This strategy is concretely implemented in the form of cellular networks and random graphs. One of our main themes is the development of the concept of physical (proto)points as densely entangled subcomplexes of the network and their respective web, establishing something like (proto)causality. It max perhaps be said that certain parts of our programme are realisations of some old and qualitative ideas of Menger and more recent ones sketched by Smolin a couple of years ago. We briefly indicate how this two-story-concept of space-time can be used to encode the (at least in our view) existing non-local aspects of quantum theory without violating macroscopic space-time causality!
(Quantum) Space-Time as a Statistical Geometry of Lumps in Random Networks
Manfred Requardt
1999-12-15
In the following we undertake to describe how macroscopic space-time (or rather, a microscopic protoform of it) is supposed to emerge as a superstructure of a web of lumps in a stochastic discrete network structure. As in preceding work (mentioned below), our analysis is based on the working philosophy that both physics and the corresponding mathematics have to be genuinely discrete on the primordial (Planck scale) level. This strategy is concretely implemented in the form of \\tit{cellular networks} and \\tit{random graphs}. One of our main themes is the development of the concept of \\tit{physical (proto)points} or \\tit{lumps} as densely entangled subcomplexes of the network and their respective web, establishing something like \\tit{(proto)causality}. It may perhaps be said that certain parts of our programme are realisations of some early ideas of Menger and more recent ones sketched by Smolin a couple of years ago. We briefly indicate how this \\tit{two-story-concept} of \\tit{quantum} space-time can be used to encode the (at least in our view) existing non-local aspects of quantum theory without violating macroscopic space-time causality.
Hierarchical Bayesian models for space-time air pollution data
Sahu, Sujit K
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
Space time coded code division multiplexing on SC140 DSP
Menon, Murali P
2001-01-01
is implemented on StarCore's SC140 fixed-point DSP core. The very large instruction word architecture of the SC140 is utilized to efficiently implement space-time coded code-division multiplexing system. The goal is to evaluate the suitability of space-time coded...
Electrodynamics on {kappa}-Minkowski space-time
Harikumar, E.; Juric, T.; Meljanac, S.
2011-10-15
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.
Geometrical Structures of Space-Time in General Relativity
Ignacio Sanchez-Rodriguez
2008-03-13
Space-Time in general relativity is a dynamical entity because it is subject to the Einstein field equations. The space-time metric provides different geometrical structures: conformal, volume, projective and linear connection. A deep understanding of them has consequences on the dynamical role played by geometry. We present a unified description of those geometrical structures, with a standard criterion of naturalness, and then we establish relationships among them and try to clarify the meaning of associated geometric magnitudes.
Wu, Yue-Liang
2015-01-01
Treating the gravitational force on the same footing as the electroweak and strong forces, we present a quantum field theory (QFT) of gravity based on spinnic and scaling gauge symmetries. The so-called Gravifield sided on both locally flat non-coordinate space-time and globally flat Minkowski space-time is an essential ingredient for gauging global spinnic and scaling symmetries. The locally flat Gravifield space-time spanned by the Gravifield is associated with a non-commutative geometry characterized by a gauge-type field strength of Gravifield. A gauge invariant and coordinate independent action for the quantum gravity is built in the Gravifield basis, we derive equations of motion for all quantum fields with including the gravitational effect and obtain basic conservation laws for all symmetries. The equation of motion for Gravifield tensor is deduced in connection directly with the energy-momentum tensor. When the spinnic and scaling gauge symmetries are broken down to a background structure that posses...
Similarity dark energy models in Bianchi type -I space-time
Ali, Ahmad T; Alzahrani, Abdulah K
2015-01-01
We investigate some new similarity solutions of anisotropic dark energy and perfect fluid in Bianchi type-I space-time. Three different time dependent skewness parameters along the spatial directions are introduced to quantify the deviation of pressure from isotropy. We consider the case when the dark energy is minimally coupled to the perfect fluid as well as direct interaction with it. The Lie symmetry generators that leave the equation invariant are identified and we generate an optimal system of one-dimensional subalgebras. Each element of the optimal system is used to reduce the partial differential equation to an ordinary differential equation which is further analyzed. We solve the Einstein field equations, described by a system of non-linear partial differential equations (NLPDEs), by using the Lie point symmetry analysis method. The geometrical and kinematical features of the models and the behavior of the anisotropy of dark energy, are examined in detail.
Space-time inhomogeneity, anisotropy and gravitational collapse
R. Sharma; R. Tikekar
2012-06-24
We investigate the evolution of non-adiabatic collapse of a shear-free spherically symmetric stellar configuration with anisotropic stresses accompanied with radial heat flux. The collapse begins from a curvature singularity with infinite mass and size on an inhomogeneous space-time background. The collapse is found to proceed without formation of an even horizon to singularity when the collapsing configuration radiates all its mass energy. The impact of inhomogeneity on various parameters of the collapsing stellar configuration is examined in some specific space-time backgrounds.
Electromagnetic space-time crystals. II. Fractal computational approach
G. N. Borzdov
2014-10-20
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.
Outage Mutual Information of Space-Time MIMO Channels
Giannakis, Georgios
Outage Mutual Information of Space-Time MIMO Channels Zhengdao Wang Georgios B. Giannakis Dept) leads to an increase in outage rate approximately equal to min(M, N), where M and N denote the number information outage probability. Finding this outage probability, as a function of R, is therefore equivalent
Temporal Index Sharding for Space-Time Efficiency
Waldmann, Uwe
each index list with almost zero increase in index size but still minimizes the cost of reading indexTemporal Index Sharding for Space-Time Efficiency in Archive Search Avishek Anand Srikanta Bedathur involve slicing either the entire collection [19] or individual index lists [9] along the time-axis. Both
New orthogonal space-time block codes with full diversity
Dalton, Lori Anne
2002-01-01
It has been shown from the Hurwitz-Radon theorem that square complex orthogonal space-time code designs cannot achieve full diversity and full rate simul-taneously, except in the two transmit antenna case. However, this result does not consider non...
Energy Distribution of a Gödel-Type Space-Time
Ragab M. Gad
2004-01-29
We calculate the energy and momentum distributions associated with a G\\"{o}del-type space-time, using the well-known energy-momentum complexes of Landau and Lifshitz and M{\\o}ller. We show that the definitions of Landau and Lifshitz and M{\\o}ller do not furnish a consistent result.
Distributional Energy-Momentum Densities of Schwarzschild Space-Time
Toshiharu Kawai; Eisaku Sakane
1997-07-14
For Schwarzschild space-time, distributional expressions of energy-momentum densities and of scalar concomitants of the curvature tensors are examined for a class of coordinate systems which includes those of the Schwarzschild and of Kerr-Schild types as special cases. The energy-momentum density $\\tilde T_\\mu^{\
Zen and the Art of Space-Time Manufacturing
Orfeu Bertolami
2013-03-10
We present a general discussion about the so-called emergent properties and discuss whether space-time and gravity can be regarded as emergent features of underlying more fundamental structures. Finally, we discuss some ideas about the multiverse, and speculate on how our universe might arise from the multiverse.
Non-commutative Einstein-Proca Space-time
Blanca Gónzales; Román Linares; Marco Maceda; Oscar Sánchez-Santos
2014-09-12
In this work we present a deformed model of Einstein-Proca space-time based on the replacement of point-like sources by non-commutative smeared distributions. We discuss the solutions to the set of non-commutative Einstein-Proca equations thus obtained, with emphasis on the issue of singularities and horizons.
Space-time models derived from Schwarzschild's solution
Lluis Bel
2008-12-09
We discuss two space-time models: one is expanding, the other is static. They are both derived from Schwarzschild's exterior solution. But they differ in the implementation of the parallelism at a distance and the choice of their master frame of reference.
Naked Singularities in Higher Dimensional Szekeres Space-time
Ujjal Debnath; Subenoy Chakraborty
2003-07-10
In this paper we study the quasi-spherical gravitational collapse of (n+2) dimensional Szekeres space-time. The nature of the central shell focusing singularity so formed is analyzed by studying both the radial null and time-like geodesic originated from it. We follow the approach of Barve et al to analyze the null geodesic and find naked singularity in different situations.
On naked singularities in higher dimensional Vaidya space-times
S. G. Ghosh; Naresh Dadhich
2001-05-28
We investigate the end state of gravitational collapse of null fluid in higher dimensional space-times. Both naked singularities and black holes are shown to be developing as final outcome of the collapse. The naked singularity spectrum in collapsing Vaidya region (4D) gets covered with increase in dimensions and hence higher dimensions favor black hole in comparison to naked singularity. The Cosmic Censorship Conjecture will be fully respected for a space of infinite dimension.
Local-time effect on small space-time scale
V. A. Panchelyuga; V. A. Kolombet; M. S. Panchelyuga; S. E. Shnoll
2006-10-18
The paper presents an investigation of local-time effect - one of the manifestations of macroscopic fluctuations phenomena. Was shown the existence of the named effect for longitudinal distance between locations of measurements up to 500 meters. Also a structure of intervals distribution in neighborhood of local-time peak was studied and splitting of the peak was found out. Obtained results lead to conclusion about sharp anisotropy of space-time.
Space-time correlations in turbulent flow: A review
Wallace, James M
2015-01-01
This paper reviews some of the principal uses, over almost seven decades, of correlations, in both Eulerian and Lagrangian frames of reference, of properties of turbulent flows at variable spatial locations and variable time instants. Commonly called space--time correlations, they have been fundamental to theories and models of turbulence as well as for the analyses of experimental and direct numerical simulation turbulence data.
The wave equation on static singular space-times
Eberhard Mayerhofer
2008-02-12
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
Formation of naked singularities in five-dimensional space-time
Yamada, Yuta; Shinkai, Hisa-aki
2011-03-15
We numerically investigate the gravitational collapse of collisionless particles in spheroidal configurations both in four- and five-dimensional (5D) space-time. We repeat the simulation performed by Shapiro and Teukolsky (1991) that announced an appearance of a naked singularity, and also find similar results in the 5D version. That is, in a collapse of a highly prolate spindle, the Kretschmann invariant blows up outside the matter and no apparent horizon forms. We also find that the collapses in 5D proceed more rapidly than in 4D, and the critical prolateness for the appearance of an apparent horizon in 5D is loosened, compared to 4D cases. We also show how collapses differ with spatial symmetries comparing 5D evolutions in single-axisymmetry, SO(3), and those in double-axisymmetry, U(1)xU(1).
Modified Brans-Dicke theory with space-time anisotropic parameters
Moon, Taeyoon [Center for Quantum Space-time, Sogang University, Seoul, 121-742 (Korea, Republic of); Oh, Phillial, E-mail: tymoon@inje.ac.kr, E-mail: ploh@skku.edu [Department of Physics and Institute of Basic Science, Sungkyunkwan University Suwon, 440-746 (Korea, Republic of)
2014-03-01
We consider the ADM formalism of the Brans-Dicke theory and propose a space-time 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 ?{sub 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.
Naked singularities in higher dimensional Vaidya space-times
Ghosh, S. G.; Dadhich, Naresh
2001-08-15
We investigate the end state of the gravitational collapse of a null fluid in higher-dimensional space-times. Both naked singularities and black holes are shown to be developing as the final outcome of the collapse. The naked singularity spectrum in a collapsing Vaidya region (4D) gets covered with the increase in dimensions and hence higher dimensions favor a black hole in comparison to a naked singularity. The cosmic censorship conjecture will be fully respected for a space of infinite dimension.
On the metric structure of space-time
Jochen Rau
2010-09-28
I present an analysis of the physical assumptions needed to obtain the metric structure of space-time. For this purpose I combine the axiomatic approach pioneered by Robb with ideas drawn from works on Weyl's "Raumproblem". The concept of a Lorentzian manifold is replaced by the weaker concept of an "event manifold", defined in terms of volume element, causal structure and affine connection(s). Exploiting properties of its structure group, I show that distinguishing Lorentzian manifolds from other classes of event manifolds requires the key idea of general relativity: namely that the manifold's physical structure, rather than being fixed, is itself a variable.
A Superstring Theory in Four Curved Space-Time Dimensions
I. Bars; K. Sfetsos
1991-11-20
Neveu-Schwarz-Ramond type heterotic and type-II superstrings in four dimensional curved space-time are constructed as exact $N=1$ superconformal theories. The tachyon is eliminated with a GSO projection. The theory is based on the N=1 superconformal gauged WZW model for the anti-de Sitter coset $SO(3,2)/SO(3,1)$ with integer central extension $k=5$. The model has dynamical duality properties in its space-time metric that are similar to the large-small ($R\\rightarrow 1/R$) duality of tori. To first order in a $1/k$ expansion we give expressions for the metric, the dilaton, the Ricci tensor and their dual generalizations. The curvature scalar has several singularities at various locations in the 4-dimensional manifold. This provides a new singular solution to Einstein's equations in the presence of matter in four dimensions. A non-trivial path integral measure which we conjectured in previous work for gauged WZW models is verified.
Effects of quantum space time foam in the neutrino sector
H. V. Klapdor-Kleingrothaus; H. Päs; U. Sarkar
2000-07-05
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.
Lightlike shell solitons of extremal space-time film
Chernitskii, Alexander A
2015-01-01
New exact solution class of Born -- Infeld type nonlinear scalar field model is obtained. The variational principle of this model has a specific form which is characteristic for extremal four-dimensional hypersurface or hyper film in five-dimensional space-time. Obtained solutions are singular solitons propagating with speed of light and having energy, momentum, and angular momentum which can be calculated for explicit conditions. The soliton singularity here is a moving two-dimensional surface or shell, where the model action density becomes zero. The lightlike soliton can have a set of tubelike shells with the appropriate cavities. A twisted lightlike soliton is considered. It is notable that its energy is proportional to its angular momentum in high-frequency approximation. A case with one tubelike cavity is considered. In this case the soliton shell is diffeomorphic to cylindrical surface with cuts by multifilar helix. The shell transverse size of the appropriate finite energy soliton can be converging to...
Classical Duality Symmetries in Two Dimensions
John H. Schwarz
1995-05-26
Many two-dimensional classical field theories have hidden symmetries that form an infinite-dimensional algebra. For those examples that correspond to effective descriptions of compactified superstring theories, the duality group is expected to be a large discrete subgroup of the hidden symmetry group. With this motivation, we explore the hidden symmetries of principal chiral models and symmetric space models.
Horizons versus singularities in spherically symmetric space-times
Bronnikov, K. A.; Elizalde, E.; Odintsov, S. D.; Zaslavskii, O. B.
2008-09-15
We discuss different kinds of Killing horizons possible in static, spherically symmetric configurations and recently classified as 'usual', 'naked', and 'truly naked' ones depending on the near-horizon behavior of transverse tidal forces acting on an extended body. We obtain the necessary conditions for the metric to be extensible beyond a horizon in terms of an arbitrary radial coordinate and show that all truly naked horizons, as well as many of those previously characterized as naked and even usual ones, do not admit an extension and therefore must be considered as singularities. Some examples are given, showing which kinds of matter are able to create specific space-times with different kinds of horizons, including truly naked ones. Among them are fluids with negative pressure and scalar fields with a particular behavior of the potential. We also discuss horizons and singularities in Kantowski-Sachs spherically symmetric cosmologies and present horizon regularity conditions in terms of an arbitrary time coordinate and proper (synchronous) time. It turns out that horizons of orders 2 and higher occur in infinite proper times in the past or future, but one-way communication with regions beyond such horizons is still possible.
L. R. G. Fontes; C. M. Newman; K. Ravishankar; E. Schertzer
2007-04-20
The dynamical discrete web (DDW), introduced in recent work of Howitt and Warren, is a system of coalescing simple symmetric one-dimensional random walks which evolve in an extra continuous dynamical parameter s. The evolution is by independent updating of the underlying Bernoulli variables indexed by discrete space-time that define the discrete web at any fixed s. In this paper, we study the existence of exceptional (random) values of s where the paths of the web do not behave like usual random walks and the Hausdorff dimension of the set of such exceptional s. Our results are motivated by those about exceptional times for dynamical percolation in high dimension by H\\"aggstrom, Peres and Steif, and in dimension two by Schramm and Steif. The exceptional behavior of the walks in DDW is rather different from the situation for dynamical random walks of Benjamini, H\\"aggstrom, Peres and Steif. In particular, we prove that there are exceptional values of s for which the walk from the origin S^s(n) has limsup S^s(n)/\\sqrt n \\leq K with a nontrivial dependence of the Hausdorff dimension on K. We also discuss how these and other results extend to the dynamical Brownian web, a natural scaling limit of DDW. The scaling limit is the focus of a paper in preparation; it was studied by Howitt and Warren and is related to the Brownian net of Sun and Swart.
Space-time complexity in solid state models
Bishop, A.R.
1985-01-01
In this Workshop on symmetry-breaking it is appropriate to include the evolving fields of nonlinear-nonequilibrium systems in which transitions to and between various degrees of ''complexity'' (including ''chaos'') occur in time or space or both. These notions naturally bring together phenomena of pattern formation and chaos and therefore have ramifications for a huge array of natural sciences - astrophysics, plasmas and lasers, hydrodynamics, field theory, materials and solid state theory, optics and electronics, biology, pattern recognition and evolution, etc. Our particular concerns here are with examples from solid state and condensed matter.
Ramin Zahedi
2015-11-11
In part I (pp. 1-10) of this article, I provide an analysis and overview of some notable definitions, works and thoughts concerning discrete physics (a.k.a. digital philosophy, digital physics or digital cosmology) that propose finite, discrete and deterministic characteristics for the physical world. Particular attention is given to theories which suggest cellular automata, as the basis of a (or the only) perfect mathematical deterministic model for the physical reality. In part II (the main part, pp.11-104, Ref. [37]) of this article, I've presented a new algebraic matrix approach based on the theory of Rings (including the Integral Domains). On the basis of this approach, by linearization (and simultaneous parameterization) followed by quantization of the relativistic energy-momentum relation, a unique set of tensor field equations are derived. These tensor equations are shown to correspond to the general forms of equations of motion of all the fundamental fields of physics, including the laws of the fundamental forces of nature (i.e. gravitational, electromagnetic and nuclear field equations), the relativistic particle wave-equations, and their generalizations. Notably, this result is primarily mathematical, assuming the relativistic energy-momentum is discrete (that is a basic and primary quantum mechanical assumption). In particular, the general theory of relativity is shown to be obtained by quantization of the special theory of relativity. Moreover, through a systematic procedure, using the tensor field equations derived and also assuming a basic discrete symmetry of physics (i.e. parity symmetry of the free particle fields), I've also shown that the universe cannot have more than four space-time dimensions (including the absence of two space-time dimensions). Subsequently, an argument for asymmetry of the left-handed and right-handed (interacting) particles is presented.
Lightlike shell solitons of extremal space-time film
Alexander A. Chernitskii
2015-10-22
New exact solution class of Born -- Infeld type nonlinear scalar field model is obtained. The variational principle of this model has a specific form which is characteristic for extremal four-dimensional hypersurface or hyper film in five-dimensional space-time. Obtained solutions are singular solitons propagating with speed of light and having energy, momentum, and angular momentum which can be calculated for explicit conditions. The soliton singularity has a form of moving two-dimensional surface or shell. The lightlike soliton can have a set of tubelike singular shells with the appropriate cavities. A twisted lightlike soliton is considered. It is notable that its energy is proportional to its angular momentum in high-frequency approximation. A case with one tubelike cavity is considered. In this case the soliton shell is diffeomorphic to cylindrical surface with cuts by multifilar helix. The shell transverse size of the appropriate finite energy soliton can be converging to zero at infinity. The ideal gas of such lightlike solitons with minimal twist parameter is considered in a finite volume. Explicit conditions provide that the angular momentum of each soliton in the volume equals Planck constant. The equilibrium energy spectral density for the solitons is obtained. It has the form of Planck distribution in some approximation. A beam of twisted lightlike solitons is considered. The representation of arbitrary polarization for beam with twisted lightlike solitons is discussed. It is shown that this beam provides the effect of mechanical angular momentum transfer to absorbent by circularly polarized beam. This effect well known for photon beam. Thus the soliton solution which have determinate likeness with photon is obtained in particular.
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)
2010-12-01
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.
PROBABILITY OF ERROR FOR TRAINED UNITARY SPACE-TIME MODULATION OVER A
Swindlehurst, A. Lee
PROBABILITY OF ERROR FOR TRAINED UNITARY SPACE-TIME MODULATION OVER A GAUSS-INNOVATIONS RICIAN probability of error for trained uni- tary space-time modulation over channels with a constant specular trained modulation, assuming that the channel is constant between training periods. All of the above
Capacity-Optimal Training for Space-Time Modulation over a Time-Varying Channel
Swindlehurst, A. Lee
Capacity-Optimal Training for Space-Time Modulation over a Time-Varying Channel Christian B. Peel-autocorrelation function for time-varying MIMO channels, we find a lower bound on capacity for trained modulation, and find for differential unitary space-time modulation is discussed and compared with that for trained modulation. We
Stephani, H.
1988-07-01
The framework of Lie--Baecklund (or generalized) symmetries is used to give a unifying view of some of the known symmetries of Einstein's field equations for the vacuum or perfect fluid case (with a ..mu.. = p or a ..mu..+3p = 0 equation of state). These symmetries occur if space-time admits one or two Killing vectors (orthogonal or parallel, respectively, to the four-velocity in the perfect fluid case).
Evidence for Non-perturbative String Symmetries
John H. Schwarz
1994-11-29
String theory appears to admit a group of discrete field transformations -- called $S$ dualities -- as exact non-perturbative quantum symmetries. Mathematically, they are rather analogous to the better-known $T$ duality symmetries, which hold perturbatively. In this talk the evidence for $S$ duality is reviewed and some speculations are presented.
Symmetry fractionalization and twist defects
Nicolas Tarantino; Netanel Lindner; Lukasz Fidkowski
2015-06-22
Topological order in two dimensions can be described in terms of deconfined quasiparticle excitations - anyons - and their braiding statistics. However, it has recently been realized that this data does not completely describe the situation in the presence of an unbroken global symmetry. In this case, there can be multiple distinct quantum phases with the same anyons and statistics, but with different patterns of symmetry fractionalization - termed symmetry enriched topological (SET) order. When the global symmetry group $G$, which we take to be discrete, does not change topological superselection sectors - i.e. does not change one type of anyon into a different type of anyon - one can imagine a local version of the action of $G$ around each anyon. This leads to projective representations and a group cohomology description of symmetry fractionalization, with $H^2(G,{\\cal A})$ being the relevant group. In this paper, we treat the general case of a symmetry group $G$ possibly permuting anyon types. We show that despite the lack of a local action of $G$, one can still make sense of a so-called twisted group cohomology description of symmetry fractionalization, and show how this data is encoded in the associativity of fusion rules of the extrinsic `twist' defects of the symmetry. Furthermore, building on work of Hermele, we construct a wide class of exactly solved models which exhibit this twisted symmetry fractionalization, and connect them to our formal framework.
The CP(N-1) Affine Gauge Theory in the Dynamical Space-time
Peter Leifer
2006-05-25
An attempt to build quantum theory of field (extended) objects without a priori space-time geometry has been represented. Space-time coordinates are replaced by the intrinsic coordinates in the tangent fibre bundle over complex projective Hilbert state space $CP(N-1)$. The fate of a quantum system modeled by the generalized coherent states is rooted in this manifold. Dynamical (state-dependent) space-time arises only at the stage of the quantum "yes/no" measurement. The quantum measurement of the gauge ``field shell'' of the generalized coherent state is described in terms of the affine parallel transport of the local dynamical variables in $CP(N-1)$.
Topological horseshoes in travelling waves of discretized nonlinear wave equations
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)
2014-04-15
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.
Space-Time Localization using Times of Arrival Sriram Venkateswaran and Upamanyu Madhow
Madhow, Upamanyu
Space-Time Localization using Times of Arrival Sriram Venkateswaran and Upamanyu Madhow Department of Electrical and Computer Engineering University of California Santa Barbara, CA 93106, USA Email: {sriram
Newtonian systems, bounded in space, time, mass and energy can compute all functions1
Martin, Ralph R.
Newtonian systems, bounded in space, time, mass and energy can compute all functions1 E.J. Beggs2, University of Wales Swansea, February 2005. 2 Department of Mathematics. Email: e.j.beggs@swansea.ac.uk 3
Quantum estimation of the Schwarzschild space-time parameters of the Earth
David Edward Bruschi; Animesh Datta; Rupert Ursin; Timothy C. Ralph; Ivette Fuentes
2014-08-31
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.
Temporal variations in space-time and progenitors of gamma ray burst and millisecond pulsars
Preston Jones
2007-08-31
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.
Symmetric Instantons and Discrete Hitchin Equations
Ward, R S
2015-01-01
Self-dual Yang-Mills instantons on $R^4$ correspond to algebraic ADHM data. This paper describes how to specialize such ADHM data so that the instantons have a $T^2$ symmetry, and this in turn motivates an integrable discrete version of the 2-dimensional Hitchin equations. It is analogous to the way in which the ADHM data for $S^1$-symmetric instantons, or hyperbolic BPS monopoles, may be viewed as a discretization of the Nahm equations.
Space-Time Models based on Random Fields with Local Interactions
Dionissios T. Hristopulos; Ivi C. Tsantili
2015-03-06
The analysis of space-time data from complex, real-life phenomena requires the use of flexible and physically motivated covariance functions. In most cases, it is not possible to explicitly solve the equations of motion for the fields or the respective covariance functions. In the statistical literature, covariance functions are often based on mathematical constructions. We propose deriving space-time covariance functions by solving "effective equations of motion", which can be used as statistical representations of systems with diffusive behavior. In particular, we propose using the linear response theory to formulate space-time covariance functions based on an equilibrium effective Hamiltonian. The effective space-time dynamics are then generated by a stochastic perturbation around the equilibrium point of the classical field Hamiltonian leading to an associated Langevin equation. We employ a Hamiltonian which extends the classical Gaussian field theory by including a curvature term and leads to a diffusive Langevin equation. Finally, we derive new forms of space-time covariance functions.
Even perturbations of the self-similar Vaidya space-time
Nolan, Brien C.; Waters, Thomas J.
2005-05-15
We study even parity metric and matter perturbations of all angular modes in self-similar Vaidya space-time. We focus on the case where the background contains a naked singularity. Initial conditions are imposed, describing a finite perturbation emerging from the portion of flat space-time preceding the matter-filled region of space-time. The most general perturbation satisfying the initial conditions is allowed to impinge upon the Cauchy horizon (CH), where the perturbation remains finite: There is no 'blue-sheet' instability. However, when the perturbation evolves through the CH and onto the second future similarity horizon of the naked singularity, divergence necessarily occurs: This surface is found to be unstable. The analysis is based on the study of individual modes following a Mellin transform of the perturbation. We present an argument that the full perturbation remains finite after resummation of the (possibly infinite number of) modes.
A superintegrable discrete harmonic oscillator based on bivariate Charlier polynomials
Vincent X. Genest; Hiroshi Miki; Luc Vinet; Guofu Yu
2015-11-30
A simple discrete model of the two dimensional isotropic harmonic oscillator is presented. It is superintegrable with su(2) as its symmetry algebra. It is constructed with the help of the algebraic properties of the bivariate Charlier polyno-mials. This adds to the other discrete superintegrable models of the oscillator based on Krawtchouk and Meixner orthogonal polynomials in several variables.
GRADIENT THEORY FOR PLASTICITY VIA HOMOGENIZATION OF DISCRETE DISLOCATIONS
Garroni, Adriana
GRADIENT THEORY FOR PLASTICITY VIA HOMOGENIZATION OF DISCRETE DISLOCATIONS ADRIANA GARRONI theory for plasticity from a model of discrete dislocations. We restrict our analysis to the case of a cylindrical symmetry for the crystal in exam, so that the mathematical formulation will involve a two
Upper bound for entropy in asymptotically de Sitter space-time
Kengo Maeda; Tatsuhiko Koike; Makoto Narita; Akihiro Ishibashi
1997-12-05
We investigate nature of asymptotically de Sitter space-times containing a black hole. We show that if the matter fields satisfy the dominant energy condition and the cosmic censorship holds in the considering space-time, the area of the cosmological event horizon for an observer approaching a future timelike infinity does not decrease, i.e. the second law is satisfied. We also show under the same conditions that the total area of the black hole and the cosmological event horizon, a quarter of which is the total Bekenstein-Hawking entropy, is less than $12\\pi/\\Lambda$, where $\\Lambda$ is a cosmological constant. Physical implications are also discussed.
Energy-momentum Prescriptions in General Spherically Symmetric Space-times
Saeed Mirshekari; Amir M. Abbassi
2014-11-29
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.
P. Danielewicz
2006-07-15
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.
Climate Projections Using Bayesian Model Averaging and Space-Time Dependence
Haran, Murali
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
High Order Space-Time Finite Element Schemes for Acoustic and Viscodynamic Wave Equations with
High Order Space-Time Finite Element Schemes for Acoustic and Viscodynamic Wave Equations in time 5 3 Specific applications 10 3.1 The acoustic wave equation, for the first time, to second order wave equations including elastodynamics with and without Kelvin
High Order Space-Time Finite Element Schemes for Acoustic and Viscodynamic Wave Equations with
High Order Space-Time Finite Element Schemes for Acoustic and Viscodynamic Wave Equations applications are to the acoustic wave equation and to elastodynamics. We also build in the well-known Kelvin for decoupled DGFEM in time 6 3 Specific applications 10 3.1 The acoustic wave equation
The stability of Killing-Cauchy horizons in colliding plane wave space-times
J. B. Griffiths
2005-01-05
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.
Information Outage Probability of Orthogonal Space-Time Block Codes over Hoyt Distributed
Rontogiannis, Athanasios A.
Information Outage Probability of Orthogonal Space-Time Block Codes over Hoyt Distributed Fading,tronto,mathio} @space.noa.gr Abstract- In this paper the information outage probabil- ity (IOP) of orthogonal space telecommunications applications. For instance, in [4] this model has been used in outage analysis of cellular mobile
Power Optimization of Wireless Media Systems with Space-Time Code Building
Yousefi'zadeh, Homayoun
between the power consumption and the quality of service in wireless media systems. Fig. 1 includes1 Power Optimization of Wireless Media Systems with Space-Time Code Building Blocks Homayoun solution to the problem of power control in wireless media systems with multiple transmit antennas. We
Power Optimization of Memoryless Wireless Media Systems with Space-Time Block Codes
Yousefi'zadeh, Homayoun
Power Optimization of Memoryless Wireless Media Systems with Space-Time Block Codes Hamid present an analytical so- lution to the problem of power control in wireless media systems with multiple- less media systems subject to a given level of Quality of Service (QoS) and an available bit rate. Our
MODELING SPACE-TIME DEPENDENT HELIUM BUBBLE EVOLUTION IN TUNGSTEN ARMOR UNDER IFE CONDITIONS
Ghoniem, Nasr M.
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 neutronMODELING SPACE-TIME DEPENDENT HELIUM BUBBLE EVOLUTION IN TUNGSTEN ARMOR UNDER IFE CONDITIONS Qiyang
New Efficient Sparse SpaceTime Algorithms for Superparameterization on Mesoscales
Xing, Yulong
New Efficient Sparse SpaceTime Algorithms for Superparameterization on Mesoscales YULONG XING-scale and mesoscale processes provided by a cloud-resolving model (CRM) embedded in each column of a large-scale model for limited-area mesoscale ensemble forecasting. 1. Introduction Atmospheric processes of weather and climate
Rapid determination of particle velocity from space-time images using the Radon transform
Cauwenberghs, Gert
Rapid determination of particle velocity from space-time images using the Radon transform Patrick J an alternative method that makes use of the Radon transform to calculate the velocity of streaming particles. We the velocity that makes use of the Radon transform (Deans 1983; Averbuch et al. 2001), which takes a set
Photons with sub-Planckian Energy Cannot Efficiently Probe Space-Time Foam
Yanbei Chen; Linqing Wen; Yiqiu Ma
2015-04-24
Extra-galactic sources of photons have been used to constrain space-time quantum fluctuations in the Universe. In these proposals, the fundamental "fuzziness" of distance caused by space-time quantum fluctuations has been directly identified with fluctuations in optical paths. Phase-front corrugations deduced from these optical-path fluctuations are then applied to light from extra-galactic point sources, and used to constrain various models of quantum gravity. However, when a photon propagates in three spatial dimensions, it does not follow a specific ray, but rather samples a finite, three-dimensional region around that ray --- thereby averaging over space-time quantum fluctuations all through that region. We use a simple, random-walk type model to demonstrate that, once the appropriate wave optics is applied, the averaging of neighboring space-time fluctuations will cause much less distortion to the phase front. In our model, the extra suppression factor due to diffraction is the wave length in units of the Planck length, which is at least $10^{29}$ for astronomical observations.
Dr. Shih-Lung Shaw's Research on Space-Time GIS, Human Dynamics and Big Data
Grissino-Mayer, Henri D.
1 Dr. Shih-Lung Shaw's Research on Space-Time GIS, Human Dynamics and Big Data for Geography dynamics and big data. We have developed spatiotemporal data models, analysis functions, and visualization. In the meantime, detailed data of individual activities and interactions are being collected by vendors (e
Photon emission in a constant magnetic field in 2+1 dimensional space-time
J. T. S. Amaral; S. I. Zlatev
2005-11-01
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.
A SpaceTime Oriented Macroprogramming Paradigm for Push-Pull Hybrid Sensor Networking
Suzuki, Jun
, called SpaceTime Oriented Programming (STOP), is designed to reduce the complexity of WSN programming are deployed in a WSN, how nodes are connected with each other and how to route data queries in a WSN. Using that al- lows application developers to implement a WSN1 appli- cation from a global viewpoint as a whole
Distributional Energy-Momentum Tensor of the Kerr-Newman Space-Time Family
Herbert Balasin; Herbert Nachbagauer
1993-12-17
Using the Kerr-Schild decomposition of the metric tensor that employs the algebraically special nature of the Kerr-Newman space-time family, we calculate the energy-momentum tensor. The latter turns out to be a well-defined tensor-distribution with disk-like support.
Optimal Trained Space-Time Modulation over a Rician Time-Varying Channel
Swindlehurst, A. Lee
Optimal Trained Space-Time Modulation over a Rician Time-Varying Channel Christian B. Peel and A investigation of modulation techniques that can handle temporally selec- tive fading. Though trained modulation for trained modulation, for example, which assume that the channel is known by the receiver. In the case
Infinite slabs and other weird plane symmetric space-times with constant positive density
Ricardo E. Gamboa Saravi
2007-09-20
We present the exact solution of Einstein's equation corresponding to a static and plane symmetric distribution of matter with constant positive density located below $z=0$. This solution depends essentially on two constants: the density $\\rho$ and a parameter $\\kappa$. We show that this space-time finishes down below at an inner singularity at finite depth. We match this solution to the vacuum one and compute the external gravitational field in terms of slab's parameters. Depending on the value of $\\kappa$, these slabs can be attractive, repulsive or neutral. In the first case, the space-time also finishes up above at another singularity. In the other cases, they turn out to be semi-infinite and asymptotically flat when $z\\to\\infty$. We also find solutions consisting of joining an attractive slab and a repulsive one, and two neutral ones. We also discuss how to assemble a "gravitational capacitor" by inserting a slice of vacuum between two such slabs.
On the extension of Newton's second law to theories of gravitation in curved space-time
Mayeul Arminjon
2006-09-14
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.
Event-by-Event Study of Space-Time Dynamics in Flux-Tube Fragmentation
Cheuk-Yin Wong
2015-10-25
In the semi-classical description of the flux-tube fragmentation process, the rapidity-space-time ordering and the local conservation laws of charge, flavor, and momentum provide a set of powerful tools that may allow the reconstruction of the space-time dynamics of quarks and mesons in the flux-tube fragmentation in event-by-event exclusive measurements of produced hadrons. Besides testing the contents of the flux tube fragmentation mechanism, additional interesting problems that may be opened up for examination by these measurements include the stochastic and quantum fluctuations in flux-tube fragmentation, the effects of multiple collisions in $pA$ and light $AA$ collisions, the interaction between flux tubes and between produced particles from different flux tubes, the effect of the merging of the flux tubes, and the occurrence of the fragmentation of ropes in $AA$ collisions, if they ever occur.
Eva Hackmann; Claus Lämmerzahl
2015-05-29
The complete set of analytic solutions of the geodesic equation in a Schwarzschild--(anti-)de Sitter space--time is presented. The solutions are derived from the Jacobi inversion problem restricted to the set of zeros of the theta function, called the theta divisor. In its final form the solutions can be expressed in terms of derivatives of Kleinian sigma functions. The different types of the resulting orbits are characterized in terms of the conserved energy and angular momentum as well as the cosmological constant. Using the analytical solution, the question whether the cosmological constant could be a cause of the Pioneer Anomaly is addressed. The periastron shift and its post--Schwarzschild limit is derived. The developed method can also be applied to the geodesic equation in higher dimensional Schwarzschild space--times.
Hackmann, Eva
2015-01-01
The complete set of analytic solutions of the geodesic equation in a Schwarzschild--(anti-)de Sitter space--time is presented. The solutions are derived from the Jacobi inversion problem restricted to the set of zeros of the theta function, called the theta divisor. In its final form the solutions can be expressed in terms of derivatives of Kleinian sigma functions. The different types of the resulting orbits are characterized in terms of the conserved energy and angular momentum as well as the cosmological constant. Using the analytical solution, the question whether the cosmological constant could be a cause of the Pioneer Anomaly is addressed. The periastron shift and its post--Schwarzschild limit is derived. The developed method can also be applied to the geodesic equation in higher dimensional Schwarzschild space--times.
Space-time curvature due to quantum vacuum fluctuations: An alternative to dark energy?
Santos, Emilio
2010-01-01
It is pointed out that quantum vacuum fluctuations may give rise to a curvature of space-time equivalent to the curvature currently attributed to dark energy. A simple calculation is made, which suggests that the value of the dark energy density is roughly given by the product of Newton constant time the quantity m^6 c^4 h^-4, m being a typical mass of elementary particles. The estimate is compatible with observations.
Space-time curvature due to quantum vacuum fluctuations: An alternative to dark energy?
Emilio Santos
2009-12-30
It is pointed out that quantum vacuum fluctuations may give rise to a curvature of space-time equivalent to the curvature currently attributed to dark energy. A simple calculation is made, which suggests that the value of the dark energy density is roughly given by the product of Newton constant time the quantity m^6 c^4 h^-4, m being a typical mass of elementary particles. The estimate is compatible with observations.
Continuous time random walk models for fractional space-time diffusion equations
Sabir Umarov
2014-09-14
In this paper continuous time random walk models approximating fractional space-time diffusion processes are studied. Stochastic processes associated with the considered equations represent time-changed processes, where the time-change process is a L\\'evy's stable subordinator with the stability index $\\beta \\in (0,1).$ In the parer the convergence of constructed CTRWs to time-changed processes associated with the corresponding fractional diffusion equations are proved using a new analytic method.
Complete analytic solution of the geodesic equation in Schwarzschild--(anti) de Sitter space--times
Eva Hackmann; Claus Lämmerzahl
2015-05-29
The complete set of analytic solutions of the geodesic equation in a Schwarzschild--(anti) de Sitter space--time is presented. The solutions are derived from the Jacobi inversion problem restricted to the theta--divisor. In its final form the solutions can be expressed in terms of derivatives of Kleinian sigma functions. The solutions are completely classified by the structure of the zeros of the characteristic polynomial which depends on the energy, angular momentum, and the cosmological constant.
Cosmological perturbations in the (1+3+6)-dimensional space-times
Kenji Tomita
2014-12-20
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 << 1, respectively, where r(t) and R(t) are the scale-factors in the outer and inner spaces. By comparing the behaviors of these perturbations, moreover, changes in the spectrum of perturbations in the outer space with time are discussed.
Asymptotically Stationary and Static Space-times and Shear-free Null Geodesic Congruences
T. M. Adamo; E. T. Newman
2009-06-12
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.
A Non-Riemannian Metric on Space-Time Emergent From Scalar Quantum Field Theory
Kar, Arnab
2012-01-01
We show that the standard deviation \\sigma(x,x') = \\sqrt{} of a scalar quantum field theory is a metric (i.e., a symmetric positive function satisfying the triangle inequality) on space-time (with imaginary time). It is very different from the Euclidean metric |x-x'|: for four dimensional free scalar field theory, \\sigma(x,x') \\to \\frac{\\sigma_{4}}{a^{2}} -\\frac{\\sigma_{4}'}{|x-x'|^{2}} + \\mathrm{O}(|x-x'|^{-3}), as |x-x'|\\to\\infty. According to \\sigma, space-time has a finite diameter \\frac{\\sigma_{4}}{a^{2}} which is not universal (i.e., depends on the UV cut-off a and the regularization method used). The Lipschitz equivalence class of the metric is independent of the cut-off. \\sigma(x,x') is not the length of the geodesic in any Riemannian metric, as it does not have the intermediate point property: for a pair (x,x') there is in general no point x" such that \\sigma(x,x')=\\sigma(x,x")+\\sigma(x",x'). Nevertheless, it is possible to embed space-time in a higher dimensional space of negative curvature so that ...
Decoupling vector wave equation, Proca and Maxwell equations in Petrov type N space-times
Koray Düzta?; ?brahim Semiz
2015-08-23
In this work we use Newman-Penrose (NP) two-spinor formalism to derive decoupled equations for vector fields in Petrov type N space-times. In the NP formalism, a four vector can be represented by one complex and two real scalars. Then, a decoupled second order differential equation for one of the real scalars can be derived from the vector wave equation if the space-time is of type N. The solution for this scalar can --in principle-- be used to derive decoupled equations for the other scalars. These results can be directly applies to Proca equation for massive vector fields. We also evaluate Maxwell equations in terms of NP complex scalars of electromagnetism. We derive a decoupled second order differential equation for $\\phi_0$, valid in type N space-times. Substituting any solution for $\\phi_0$ in Maxwell equations, leads to two first order differential equations for $\\phi_1$. We show that these first order equations identically satisfy integrability conditions. Thus, any solution for $\\phi_0$ guarantees the existence of a solution for $\\phi_1$, via either of the first order differential equations.
Stress-energy tensor in colliding plane wave space-times: An approximation procedure
Miquel Dorca
1997-11-07
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.
TASI Lectures on Holographic Space-Time, SUSY and Gravitational Effective Field Theory
Tom Banks
2010-09-23
I argue that the conventional field theoretic notion of vacuum state is not valid in quantum gravity. The arguments use gravitational effective field theory, as well as results from string theory, particularly the AdS/CFT correspondence. Different solutions of the same low energy gravitational field equations correspond to different quantum systems, rather than different states in the same system. I then introduce {\\it holographic space-time} a quasi-local quantum mechanical construction based on the holographic principle. I argue that models of quantum gravity in asymptotically flat space-time will be exactly super-Poincare invariant, because the natural variables of holographic space-time for such a system, are the degrees of freedom of massless superparticles. The formalism leads to a non-singular quantum Big Bang cosmology, in which the asymptotic future is required to be a de Sitter space, with cosmological constant (c.c.) determined by cosmological initial conditions. It is also approximately SUSic in the future, with the gravitino mass $K \\Lambda^{1/4}$.
Xavier Busch
2014-11-06
The two main predictions of quantum field theory in curved space-time, namely Hawking radiation and cosmological pair production, have not been directly tested and involve ultra high energy configurations. As a consequence, they should be considered with caution. Using the analogy with condensed matter systems, their analogue versions could be tested in the lab. Moreover, the high energy behavior of these systems is known and involves dispersion and dissipation, which regulate the theory at short distances. When considering experiments which aim to test the above predictions, there will also be a competition between the stimulated emission from thermal noise and the spontaneous emission out of vacuum. In order to measure these effects, one should thus compute the consequences of UV dispersion and dissipation, and identify observables able to establish that the spontaneous emission took place. In this thesis, we first analyze the effects of dispersion and dissipation on both Hawking radiation and pair particle production. To get explicit results, we work in the context of de Sitter space. Using the extended symmetries of the theory in such a background, exact results are obtained. These are then transposed to the context of black holes using the correspondence between de Sitter space and the black hole near horizon region. To introduce dissipation, we consider an exactly solvable model producing any decay rate. We also study the quantum entanglement of the particles so produced. In a second part, we consider explicit condensed matter systems, namely Bose Einstein condensates and exciton-polariton systems. We analyze the effects of dissipation on entanglement produced by the dynamical Casimir effect. As a final step, we study the entanglement of Hawking radiation in the presence of dispersion for a generic analogue system.
Non-trivial, static, geodesically complete space-times with a negative cosmological constant II. n 5
Anderson, Michael
Non-trivial, static, geodesically complete space-times with a negative cosmological constant II. n that the recent work of Lee [24] implies existence of a large class of new singularity-free strictly static in all space-time dimensions greater than or equal to four, and leads both to strictly static solutions
None
2011-10-06
- 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
Discrete Scale Relativity And SX Phoenicis Variable Stars
R. L. Oldershaw
2009-06-18
Discrete Scale Relativity proposes a new symmetry principle called discrete cosmological self-similarity which relates each class of systems and phenomena on a given Scale of nature's discrete cosmological hierarchy to the equivalent class of analogue systems and phenomena on any other Scale. The new symmetry principle can be understood in terms of discrete scale invariance involving the spatial, temporal and dynamic parameters of all systems and phenomena. This new paradigm predicts a rigorous discrete self-similarity between Stellar Scale variable stars and Atomic Scale excited atoms undergoing energy-level transitions and sub-threshold oscillations. Previously, methods for demonstrating and testing the proposed symmetry principle have been applied to RR Lyrae, Delta Scuti and ZZ Ceti variable stars. In the present paper we apply the same analytical methods and diagnostic tests to a new class of variable stars: SX Phoenicis variables. Double-mode pulsators are shown to provide an especially useful means of testing the uniqueness and rigor of the conceptual principles and discrete self-similar scaling of Discrete Scale Relativity.
Exact solutions of (n+1)-dimensional Yang-Mills equations in curved space-time
Sanchez-Monroy, J.A.; Quimbay, C.J.
2012-09-15
In the context of a semiclassical approach where vectorial gauge fields can be considered as classical fields, we obtain exact static solutions of the SU(N) Yang-Mills equations in an (n+1)-dimensional curved space-time, for the cases n=1,2,3. As an application of the results obtained for the case n=3, we consider the solutions for the anti-de Sitter and Schwarzschild metrics. We show that these solutions have a confining behavior and can be considered as a first step in the study of the corrections of the spectra of quarkonia in a curved background. Since the solutions that we find in this work are valid also for the group U(1), the case n=2 is a description of the (2+1) electrodynamics in the presence of a point charge. For this case, the solution has a confining behavior and can be considered as an application of the planar electrodynamics in a curved space-time. Finally we find that the solution for the case n=1 is invariant under a parity transformation and has the form of a linear confining solution. - Highlights: Black-Right-Pointing-Pointer We study exact static confining solutions of the SU(N) Yang-Mills equations in an (n+1)-dimensional curved space-time. Black-Right-Pointing-Pointer The solutions found are a first step in the study of the corrections on the spectra of quarkonia in a curved background. Black-Right-Pointing-Pointer A expression for the confinement potential in low dimensionality is found.
N. Seiberg; L. Susskind; N. Toumbas
2000-05-04
Searching for space/time noncommutativity we reconsider open strings in a constant background electric field. The main difference between this situation and its magnetic counterpart is that here there is a critical electric field beyond which the theory does not make sense. We show that this critical field prevents us from finding a limit in which the theory becomes a field theory on a noncommutative spacetime. However, an appropriate limit toward the critical field leads to a novel noncritical string theory on a noncommutative spacetime.
Information content of nonautonomous free fields in curved space-time
Parreira, J. E.; Nemes, M. C.; Fonseca-Romero, K. M.
2011-03-15
We show that it is possible to quantify the information content of a nonautonomous free field state in curved space-time. A covariance matrix is defined and it is shown that, for symmetric Gaussian field states, the matrix is connected to the entropy of the state. This connection is maintained throughout a quadratic nonautonomous (including possible phase transitions) evolution. Although particle-antiparticle correlations are dynamically generated, the evolution is isoentropic. If the current standard cosmological model for the inflationary period is correct, in absence of decoherence such correlations will be preserved, and could potentially lead to observable effects, allowing for a test of the model.
On the local form of static plane symmetric space-times in the presence of matter
Leandro G. Gomes
2015-02-10
For any configuration of a static plane-symmetric distribution of matter along space-time, there are coordinates where the metric can be put explicitly as a functional of the energy density and pressures. It satisfies Einstein equations as far as we require the conservation of the energy-momentum tensor, which is the single ODE for self-gravitating hydrostatic equilibrium. As a direct application, a general solution is given when the pressures are linearly related to the energy density, recovering, as special cases, most of known solutions of static plane-symmetric Einstein equations.
Boundary Effects on Bose-Einstein Condensation in Ultra-Static Space-Times
L. Akant; E. Ertugrul; Y. Gul; O. T. Turgut
2015-05-13
The boundary effects on the Bose-Einstein condensation of a Bose gas with a nonvanishing chemical potential on an ultra-static space-time are studied. High temperature 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 high temperature expansion in the presence of a chemical potential is generated via the Mellin transform methods as applied to the harmonic sums representing the free energy and the depletion coefficient. The effects of boundary conditions on the relation between depletion coefficient and temperature are analyzed. The analysis is done for both charged and neutral bosons.
A space-time characterization of the Kerr-Newman metric
Willie Wai-Yeung Wong
2009-01-30
In the present paper, the characterization of the Kerr metric found by Marc Mars is extended to the Kerr-Newman family. A simultaneous alignment of the Maxwell field, the Ernst two-form of the pseudo-stationary Killing vector field, and the Weyl curvature of the metric is shown to imply that the space-time is locally isometric to domains in the Kerr-Newman metric. The paper also presents an extension of Ionescu and Klainerman's null tetrad formalism to explicitly include Ricci curvature terms.
Energy and Momentum Distributions of Kantowski and Sachs Space-time
Ragab M. Gad; A. Fouad
2007-04-15
We use the Einstein, Bergmann-Thomson, Landau-Lifshitz and Papapetrou energy-momentum complexes to calculate the energy and momentum distributions of Kantowski and Sachs space-time. We show that the Einstein and Bergmann-Thomson definitions furnish a consistent result for the energy distribution, but the definition of Landau-Lifshitz do not agree with them. We show that a signature switch should affect about everything including energy distribution in the case of Einstein and Papapetrou prescriptions but not in Bergmann-Thomson and Landau-Lifshitz prescriptions.
Fuzzy Geometry via the Spinor Bundle, with Applications to Holographic Space-time and Matrix Theory
Tom Banks; John Kehayias
2011-11-02
We present a new framework for defining fuzzy approximations to geometry in terms of a cutoff on the spectrum of the Dirac operator, and a generalization of it that we call the Dirac-Flux operator. This framework does not require a symplectic form on the manifold, and is completely rotation invariant on an arbitrary n-sphere. The framework is motivated by the formalism of Holographic Space-Time (HST), whose fundamental variables are sections of the spinor bundle over a compact Euclidean manifold. The strong holographic principle (SHP) requires the space of these sections to be finite dimensional. We discuss applications of fuzzy spinor geometry to HST and to Matrix Theory.
Energy of gravitational radiation in plane-symmetric space-times
Sean A. Hayward
2008-05-19
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.
Stringy models of modified gravity: space-time defects and structure formation
Mavromatos, Nick E.; Sakellariadou, Mairi; Yusaf, Muhammad Furqaan, E-mail: nikolaos.mavromatos@kcl.ac.uk, E-mail: mairi.sakellariadou@kcl.ac.uk, E-mail: muhammad.yusaf@kcl.ac.uk [King's College London, Department of Physics, Strand, London WC2R 2LS (United Kingdom)
2013-03-01
Starting from microscopic models of space-time foam, based on brane universes propagating in bulk space-times populated by D0-brane defects (''D-particles''), we arrive at effective actions used by a low-energy observer on the brane world to describe his/her observations of the Universe. These actions include, apart from the metric tensor field, also scalar (dilaton) and vector fields, the latter describing the interactions of low-energy matter on the brane world with the recoiling point-like space-time defect (D-particle). The vector field is proportional to the recoil velocity of the D-particle and as such it satisfies a certain constraint. The vector breaks locally Lorentz invariance, which however is assumed to be conserved on average in a space-time foam situation, involving the interaction of matter with populations of D-particle defects. In this paper we clarify the role of fluctuations of the vector field on structure formation and galactic growth. In particular we demonstrate that, already at the end of the radiation era, the (constrained) vector field associated with the recoil of the defects provides the seeds for a growing mode in the evolution of the Universe. Such a growing mode survives during the matter dominated era, provided the variance of the D-particle recoil velocities on the brane is larger than a critical value. We note that in this model, as a result of specific properties of D-brane dynamics in the bulk, there is no issue of overclosing the brane Universe for large defect densities. Thus, in these models, the presence of defects may be associated with large-structure formation. Although our string inspired models do have (conventional, from a particle physics point of view) dark matter components, nevertheless it is interesting that the role of ''extra'' dark matter is also provided by the population of massive defects. This is consistent with the weakly interacting character of the D-particle defects, which predominantly interact only gravitationally.
O. Babelon; D. Bernard
1991-11-20
We study Lie-Poisson actions on symplectic manifolds. We show that they are generated by non-Abelian Hamiltonians. We apply this result to the group of dressing transformations in soliton theories; we find that the non-Abelian Hamiltonian is just the monodromy matrix. This provides a new proof of their Lie-Poisson property. We show that the dressing transformations are the classical precursors of the non-local and quantum group symmetries of these theories. We treat in detail the examples of the Toda field theories and the Heisenberg model.
The perturbation equation of a static symmetrical homogeneous space-time
Jose L. Martinez-Morales
2009-09-26
In absence of explicit solutions of the perturbation equation of a static symmetrical homogeneous space-time, the best we can do is to construct a {\\it quasi-}transformation. In this framework, we solve the perturbation equation with initial data and a number of results are derived. Far from the horizon of a black hole of even space dimension $N$, a mass-less field decays as ${r^l} {{(-{r^2}+{t^2})}^{\\frac{1-N}{2}-l}}$ in space-time, where $l$ is a harmonic number of the sphere. A relation of energy and momentum of a particle with mass in a hyper black hole is discovered and a solution to the equation of Klein-Gordon in the metric of Schwarzschild-Tangherlini with initial data on the hypersphere is proposed. Also, the Green's function of the Klein-Gordon equation in Schwarzschild coordinates is calculated. This function is a sum on the harmonic modes of the sphere. The first term is a double integration on the spectrum of energy and the momentum of the particle. Far from the horizon, the double integration is approximated by an integration on a line defined by the relation of energy and momentum of a free particle. From here, the potential of Yukawa is derived. Finally, the linear perturbation equations are derived and solved exactly.
Self-force on an arbitrarily coupled static scalar particle in a wormhole space-time
Peter Taylor
2012-10-20
In this paper, we consider the problem of computing the self-force and self-energy for a static scalar charge in a wormhole space-time with throat profile $r(\\rho)=\\sqrt{\\rho^{2}+a^{2}}$ for arbitrary coupling of the field to the curvature. This calculation has previously been considered numerically by Bezerra and Khusnutdinov, while analytic results have been obtained in the special cases of minimal ($\\xi=0$) coupling and conformal coupling ($\\xi=1/8$ in three dimensions). We present here a closed form expression for the static Green's function for arbitrary coupling and hence we obtain an analytic expression for the self-force. The self-force depends crucially on the coupling of the field to the curvature of the space-time and hence it is useful to determine the dependence explicitly. The numerical computation can identify some qualitative aspects of this dependence such as the change in the sign of the force as it passes through the conformally coupled value, as well as the fact that the self-force diverges for $\\xi=1/2$. From the closed form expression, it is straight-forward to see that there is an infinite set of values of the coupling constant for which the self-force diverges, but we also see that there is an infinite set of values for which the self-force vanishes.
Self-similar space-time evolution of an initial density discontinuity
Rekaa, V. L.; Pécseli, H. L.; Trulsen, J. K.
2013-07-15
The space-time evolution of an initial step-like plasma density variation is studied. We give particular attention to formulate the problem in a way that opens for the possibility of realizing the conditions experimentally. After a short transient time interval of the order of the electron plasma period, the solution is self-similar as illustrated by a video where the space-time evolution is reduced to be a function of the ratio x/t. Solutions of this form are usually found for problems without characteristic length and time scales, in our case the quasi-neutral limit. By introducing ion collisions with neutrals into the numerical analysis, we introduce a length scale, the collisional mean free path. We study the breakdown of the self-similarity of the solution as the mean free path is made shorter than the system length. Analytical results are presented for charge exchange collisions, demonstrating a short time collisionless evolution with an ensuing long time diffusive relaxation of the initial perturbation. For large times, we find a diffusion equation as the limiting analytical form for a charge-exchange collisional plasma, with a diffusion coefficient defined as the square of the ion sound speed divided by the (constant) ion collision frequency. The ion-neutral collision frequency acts as a parameter that allows a collisionless result to be obtained in one limit, while the solution of a diffusion equation is recovered in the opposite limit of large collision frequencies.
Optical models of the big bang and non-trivial space-time metrics based on metamaterials
Igor I. Smolyaninov
2009-08-17
Optics of metamaterials is shown to provide interesting table top models of many non-trivial space-time metrics. The range of possibilities is broader than the one allowed in classical general relativity. For example, extraordinary waves in indefinite metamaterials experience an effective metric, which is formally equivalent to the "two times physics" model in 2+2 dimensions. An optical analogue of a "big bang" event is presented during which a (2+1) Minkowski space-time is created together with large number of particles populating this space-time. Such metamaterial models enable experimental exploration of the metric phase transitions to and from the Minkowski space-time as a function of temperature and/or light frequency.
Saskia Grunau; Valeria Kagramanova
2010-11-24
We present the full set of analytical solutions of the geodesic equations of charged test particles in the Reissner-Nordstr\\"om space-time in terms of the Weierstra{\\ss} $\\wp$, $\\sigma$ and $\\zeta$ elliptic functions. Based on the study of the polynomials in the $\\vartheta$ and $r$ equations we characterize the motion of test particles and discuss their properties. The motion of charged test particles in the Reissner-Nordstr\\"om space-time is compared with the motion of neutral test particles in the field of a gravitomagnetic monopole. Electrically or magnetically charged particles in the Reissner-Nordstr\\"om space-time with magnetic or electric charges, respectively, move on cones similar to neutral test particles in the Taub-NUT space-times.
Energy dependence of space-time extent of pion source in nuclear collisions
V. A. Okorokov
2015-04-30
Energy dependence of space-time parameters of pion emission region at freeze-out is studied for collisions of various ions and for all experimentally available energies. The using of femtoscopic radii scaled on the averaged radius of colliding ions is suggested. This approach allows the expansion of the set of interaction types, in particular, on collisions of non-symmetrical ion beams which can be studied within the framework of common treatment. There is no sharp changing of femtoscopic parameter values with increasing of initial energy. Analytic functions suggested for smooth approximations of energy dependence of femtoscopic parameters demonstrate reasonable agreement with most of experimental data at $\\sqrt{s_{NN}} \\geq 5$ GeV. Estimations of some observables are obtained for energies of the LHC and FCC project.
Muhammad Nadeem
2015-05-07
Secure positioning, a prover located at a specified position convinces a set of verifiers at distant reference stations that he/she is indeed at the specific position, is considered to be impossible if the prover and verifiers have no pre-shared data while dishonest provers have an arbitrary amount of pre-shared entanglement [Nature 479, 307-308 (2011)]. We argue here that current impossibility results for secure positioning are the upshot of not utilizing full powers of relativistic quantum information theory and show that secure positioning and hence position-based quantum cryptography is possible if causal structure of Minkowski space time and quantum non-locality is used properly.
Renormalized Free Energy on Space-time with Compact Hyperbolic Spatial Part
Rosevaldo de Oliveira
2010-05-19
In this paper we found the renormalized free energy of a interacting scalar field on a compact hyperbolic manifold explicitly. We have shown a complete expression of the free energy and entropy as a function of the curvature and the temperature. Carefully analyzing the free energy we have shown that there exist a minimum with respect to the curvature that depend on the temperature. The principle of minimum free energy give us an estimate of the connection between stationary curvature and temperature. As a result we obtain that the stationary curvature increases when the temperature increases too. If we start from an universe with very high curvature and temperature in the beginning, because of the principle of minimum free energy, the universe will reach a new situation of equilibrium for low temperature and low curvature. Consequently, the flat space-time is obtained for low temperature.
The geometry of the space-time and motion of the spinning bodies
Kostadin Trencevski
2015-04-19
In this paper an alternative theory about space-time is given. First some preliminaries about 3-dimensional time and the reasons for its introduction are presented. Alongside the 3-dimensional space (S) the 3-dimensional space of spatial rotations (SR) is considered independently from the 3-dimensional space. Then it is given a model of the universe, based on the Lie groups of real and complex orthogonal 3x3 matrices in this 3+3+3-dimensional space. Special attention is dedicated for introduction and study of the space SxSR, which appears to be isomorphic to SO(3,R)xSO(3,R) or S^3xS^3. The influence of the gravitational acceleration to the spinning bodies is considered. Some important applications of these results about spinning bodies are given, which naturally lead to violation of Newton's third law in its classical formulation. The precession of the spinning axis is also considered.
On Non-Equilibrium Thermodynamics of Space-Time and Quantum Gravity
Joakim Munkhammar
2015-07-02
Based on recent results from general relativistic statistical mechanics and black hole information transfer limits a space-time entropy-action equivalence is proposed as a generalization of the holographic principle. With this conjecture, the action principle can be replaced by the second law of thermodynamics, and for the Einstein-Hilbert action the Einstein field equations are conceptually the result of thermodynamic equilibrium. For non-equilibrium situations Jaynes' information-theoretic approach to maximum entropy production is adopted instead of the second law of thermodynamics. As it turns out, for appropriate choices of constants quantum gravity is obtained. For the special case of a free particle the Bekenstein-Verlinde entropy-to-displacement relation of holographic gravity, and thus the traditional holographic principle, emerges. Although Jacobson's original thermodynamic equilibrium approach proposed that gravity might not necessarily be quantized, this particular non-equilibrium treatment might require it.
Holographic Space-time and Black Holes: Mirages As Alternate Reality
Tom Banks; Willy Fischler; Sandipan Kundu; Juan F. Pedraza
2014-01-30
We revisit our investigation of the claim of [1] that old black holes contain a firewall, i.e. an in-falling observer encounters highly excited states at a time much shorter than the light crossing time of the Schwarzschild radius. We used the formalism of Holographic Space-time (HST) where there is no dramatic change in particle physics inside the horizon until a time of order the Schwarzschild radius. We correct our description of the interior of the black hole . HST provides a complete description of the quantum mechanics along any time-like trajectory, even those which fall through the black hole horizon. The latter are described as alternative factorizations of the description of an external observer, turning the mirage of the interior provided by that observer's membrane paradigm on the stretched horizon, into reality.
Spontaneous breaking of SU(3) to finite family symmetries: a pedestrian's approach
Christoph Luhn
2011-01-12
Non-Abelian discrete family symmetries play a pivotal role in the formulation of models with tri-bimaximal lepton mixing. We discuss how to obtain symmetries such as A4, semidirect product of Z7 and Z3, and Delta(27) from an underlying SU(3) gauge symmetry. Higher irreducible representations are required to achieve the spontaneous breaking of the continuous group. We present methods of identifying the required vacuum alignments and discuss in detail the symmetry breaking potentials.
Origin of matter and space-time in the big bang
Mathews, G. J.; Yamazaki, D.; Kusakabe, M.; Cheoun, M.-K.
2014-05-02
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.
Spinning particles in vacuum space-times of different curvature types -- I
O. Semerák; M. Šrámek
2015-05-05
We consider the motion of spinning test particles with non-zero rest mass in the "pole-dipole" approximation, as described by the Mathisson--Papapetrou--Dixon (MPD) equations, and examine its properties in dependence on the spin supplementary condition added to close the system and on algebraic type of curvature. The MPD equation of motion is first decomposed in the orthonormal tetrad whose time-like vector is given by the four-velocity $V^\\mu$ fixing the spin condition (the "reference observer") and the first spatial vector by the corresponding spin $s^\\mu$; such MPD-equation projections do not contain the Weyl scalars $\\Psi_0$ and $\\Psi_4$ obtained in the related Newman--Penrose null tetrad. One natural option how to choose the remaining two spatial basis vectors, is shown to follow "intrinsically" whenever the reference observer $V^\\mu$ has been chosen; it is realizable if the particle's four-velocity and four-momentum are not parallel. In order to discuss the problem in dependence on space-time Petrov type, it is natural to align the real vectors of the Newman--Penrose tetrad with the Weyl-tensor principal null directions (and thus to set $V^\\mu$ and $s^\\mu$ accordingly). In space-times of any algebraic type but III, it is moreover possible to rotate the tetrad so as to become "transverse", namely so that $\\Psi_1$ and $\\Psi_3$ vanish; the spinning-particle motion is then fully determined by $\\Psi_2$ and the cosmological constant. Besides focusing on specific Petrov types, we derive several sets of useful relations valid generally and check whether/how the exercise simplifies for some particular types of motion. The option of having four-velocity parallel to four-momentum is treated in some detail and a natural resolution of non-uniqueness of the corresponding reference observer $V^\\mu$ is suggested.
J. Brian Pitts
2015-09-09
Klein-Gordon gravity, 1920s-30s particle physics, and 1890s Neumann-Seeliger modified gravity suggest a "graviton mass term" *algebraic* in the potential. Unlike Nordstr\\"om's "massless" theory, massive scalar gravity is invariant under the Poincar\\'e group but not the 15-parameter conformal group. It thus exhibits the whole Minkowski space-time structure, indirectly for volumes. Massive scalar gravity is plausible as a field theory, but violates Einstein's principles of general covariance, general relativity, equivalence, and Mach. Geometry is a poor guide: matter sees a conformally flat metric due to universal coupling, but gravity sees the rest of the flat metric (on long distances) in the mass term. What is the `true' geometry, in line with Poincar\\'e's modal conventionality argument? Infinitely many theories exhibit this bimetric `geometry,' all with the total stress-energy's trace as source; geometry does not explain the field equations. The irrelevance of the Ehlers-Pirani-Schild construction to conventionalism is evident given multi-geometry theories. As Seeliger envisaged, the smooth massless limit yields underdetermination between massless and massive scalar gravities---an unconceived alternative. One version easily could have been developed before GR; it would have motivated thinking of Einstein's equations along the lines of his newly reappreciated "physical strategy" and suggested a rivalry from massive spin 2 for GR (massless spin 2, Pauli-Fierz 1939). The Putnam-Gr\\"unbaum debate on conventionality is revisited given a broad modal scope. Massive scalar gravity licenses a historically plausible rational reconstruction of much of space-time philosophy in light of particle physics. An appendix reconsiders the Malament-Weatherall-Manchak conformal restriction of conventionality and constructs the `universal force' in the null cones.
Symmetry in Nature Applications of Symmetry
. · water (H2O) · methane (CH4) · ammonia (NH3) · oxygen gas (O2) · nitrogen gas (N2) · hydrogen bromideSymmetry in Nature Applications of Symmetry Homework Assignment Week 3 1. Complete the following
Generalized discrete orbit function transforms of affine Weyl groups
Tomasz Czy?ycki; Ji?í Hrivnák
2014-11-14
The affine Weyl groups with their corresponding four types of orbit functions are considered. Two independent admissible shifts, which preserve the symmetries of the weight and the dual weight lattices, are classified. Finite subsets of the shifted weight and the shifted dual weight lattices, which serve as a sampling grid and a set of labels of the orbit functions, respectively, are introduced. The complete sets of discretely orthogonal orbit functions over the sampling grids are found and the corresponding discrete Fourier transforms are formulated. The eight standard one-dimensional discrete cosine and sine transforms form special cases of the presented transforms.
Constraint analysis for variational discrete systems
Dittrich, Bianca; Höhn, Philipp A.; Institute for Theoretical Physics, Universiteit Utrecht, Leuvenlaan 4, NL-3584 CE Utrecht
2013-09-15
A canonical formalism and constraint analysis for discrete systems subject to a variational action principle are devised. The formalism is equivalent to the covariant formulation, encompasses global and local discrete time evolution moves and naturally incorporates both constant and evolving phase spaces, the latter of which is necessary for a time varying discretization. The different roles of constraints in the discrete and the conditions under which they are first or second class and/or symmetry generators are clarified. The (non-) preservation of constraints and the symplectic structure is discussed; on evolving phase spaces the number of constraints at a fixed time step depends on the initial and final time step of evolution. Moreover, the definition of observables and a reduced phase space is provided; again, on evolving phase spaces the notion of an observable as a propagating degree of freedom requires specification of an initial and final step and crucially depends on this choice, in contrast to the continuum. However, upon restriction to translation invariant systems, one regains the usual time step independence of canonical concepts. This analysis applies, e.g., to discrete mechanics, lattice field theory, quantum gravity models, and numerical analysis.
Lee, Ming S.; McNally, Michael G.
2002-01-01
J. (2000) Using desktop GIS for the investigation ofSpace - Time Prisms in a GIS: A Case Health- Study of Accesswith Space-Time Prisms in a GIS: A Case Study of Access to
Discrete Fracture Reservoir Simulation
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Discrete Fracture Reservoir Simulation Shale Gas Flow Simulation Shale Gas Flow Simulation FRACGENNFFLOW, fractured reservoir modeling software developed by NETL's Geological and...
Space-time-wavelength mapping: a new approach for electronic control of optical tweezers
Rahman, Shah; Zhao, Qiancheng; Atasever, Tuva; Boyraz, Ozdal
2015-01-01
We present a new approach for electronic control of optical tweezers. The key technique, called 'space-time-wavelength mapping', involves time-domain modulation which is translated onto spatial domain by diffraction and enables direct control of location and polarity of force hot-spots created by Lorentz force (gradient force). In this study 150 fs optical pulses are dispersed in time and space to achieve a focused elliptical beam that is ~20 {\\mu}m long and ~2 {\\mu}m wide. In order to manipulate the intensity gradient along the beam at the focal spot, we use an electro-optic modulator to modulate power spectral distribution of the femtosecond beam after temporal dispersion. The electro-optic modulator is supplied with a chosen RF waveform that dictates the manipulation of the power spectral distribution. By choosing the appropriate RF waveform, it is possible to create force fields for cell stretching and compression as well as multiple hot spots (of > 200 pN force) for attractive or repulsive forces. We pre...
Cormac Breen; Adrian C. Ottewill
2012-01-11
We consider a quantum field which is in a Hartle-Hawking state propagating in a general spherically symmetric black hole space-time. We make use of uniform approximations to the radial equation to calculate the components of the stress tensor, renormalized using the Hadamard form of the Green's function, on the horizons of this space-time. We then specialize these results to the case of the `lukewarm' Reissner-Nordstrom-de Sitter black hole and derive some conditions on the stress tensor for the regularity of the Hartle-Hawking state.
Morris, J; Johnson, S
2007-12-03
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.
Automorphic Lie Algebras with dihedral symmetry
Vincent Knibbeler; Sara Lombardo; Jan A Sanders
2014-10-10
The concept of Automorphic Lie Algebras arises in the context of reduction groups introduced in the early 1980s in the field of integrable systems. Automorphic Lie Algebras are obtained by imposing a discrete group symmetry on a current algebra of Krichever-Novikov type. Past work shows remarkable uniformity between algebras associated to different reduction groups. For example, if the base Lie algebra is $\\mathfrak{sl}_2(\\mathbb{C})$ and the poles of the Automorphic Lie Algebra are restricted to an exceptional orbit of the symmetry group, changing the reduction group does not affect the Lie algebra structure. In the present research we fix the reduction group to be the dihedral group and vary the orbit of poles as well as the group action on the base Lie algebra. We find a uniform description of Automorphic Lie Algebras with dihedral symmetry, valid for poles at exceptional and generic orbits.
Journal of Applied Ecology (1987) 24, 435-450 SPACE-TIME STRUCTURES IN A WINTER RAPE
Thioulouse, Jean
1987-01-01
Journal of Applied Ecology (1987) 24, 435-450 SPACE-TIME STRUCTURES IN A WINTER RAPE PEST, and correspondence analysis are used to describe spatial and temporal structure in a population of a winter rape pest (Psylliodes chrysocephala L.) and its host plant, the winter rape (Brassica napus L.). This pest has been
Dr. Shih-Lung Shaw, Department of Geography, UTK A Space-Time GIS for Analyzing Human Activities
Wang, Xiaorui "Ray"
Dr. Shih-Lung Shaw, Department of Geography, UTK A Space-Time GIS for Analyzing Human Activities and Interactions in Physical and Virtual Spaces Shih-Lung Shaw, Ph.D. Department of Geography University. Shih-Lung Shaw, Department of Geography, UTK "Imagine that your business had a complete log of your
Non-trivial, static, geodesically complete space-times with a negative cosmological constant II. n 5
Anderson, Michael
Non-trivial, static, geodesically complete space-times with a negative cosmological-free strictly static Lorentzian vacuum solutions * *of the Einstein equations with a negative cosmological to strictly static solutions and to black hole solutions. The construction allows in principle
Non-trivial, static, geodesically complete space-times with a negative cosmological constant II. n 5
Delay, Erwann
Non-trivial, static, geodesically complete space-times with a negative cosmological constant II. n [24] implies existence of a large class of new singularity-free strictly static Lorentzian vacuum-time dimensions greater than or equal to four, and leads both to strictly static solutions and to black hole
So, Hing-Cheung
antenna scheme is feasible. Index Terms--Beamforming, smart antennas, space-time coding, transmit City University of Hong Kong, Hong Kong, under Project 7001383. L. Ping is with the Department of Electronic Engineering, City University of Hong Kong, Kowloon, Hong Kong (e-mail: eeliping@cityu.edu.hk). L
$K_S$ semileptonic decays and test of $\\mathcal{CPT}$ symmetry with the KLOE detector
D. Kami?ska
2015-01-19
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.
Enhancement of hidden symmetries and Chern-Simons couplings
Marc Henneaux; Axel Kleinschmidt; Victor Lekeu
2015-05-27
We study the role of Chern--Simons couplings for the appearance of enhanced symmetries of Cremmer--Julia type in various theories. It is shown explicitly that for generic values of the Chern--Simons coupling there is only a parabolic Lie subgroup of symmetries after reduction to three space-time dimensions but that this parabolic Lie group gets enhanced to the full and larger Cremmer--Julia Lie group of hidden symmetries if the coupling takes a specific value. This is heralded by an enhanced isotropy group of the metric on the scalar manifold. Examples of this phenomenon are discussed as well as the relation to supersymmetry. Our results are also connected with rigidity theorems of Borel-like algebras.
Gupalo, D.; Kaganovich, A.S.; Cohen, E.G.D. (Rockefeller Univ., New York, NY (United States))
1994-03-01
The symmetry of the spectrum of Lyapunov exponents provides a useful quantitative connection between properties of dynamical systems consisting of N interacting particles coupled to a thermostat, and nonequilibrium statistical mechanics. The authors obtain here sufficient conditions for this symmetry and analyze the structure of 1/N corrections ignored in previous studies. The relation of the Lyapunov spectrum symmetry with some other symmetries of dynamical systems is discussed.
Roelof Bijker
2005-09-02
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.
Discrete Fourier Transform Javier Montoya
Giger, Christine
Discrete Fourier Transform Javier Montoya Photogrammetry and Remote Sensing ETH Zurich March 16, 2012 1 Introduction The Discrete form of the Fourier transform is known as Discrete Fourier Transform domain using the Inverse Discrete Fourier Transform (IDFT): f(x) = 1 N N-1 x=0 F(u)ej 2 N ux for u = 0, 1
A discrete fractional random transform
Zhengjun Liu; Haifa Zhao; Shutian Liu
2006-05-20
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.
Bulk photons in Asymmetrically Warped Space-times and Non-trivial Vacuum Refractive Index
K. Farakos; N. E. Mavromatos; P. Pasipoularides
2009-01-20
We consider asymmetrically warped brane models, or equivalently brane models where the background metric is characterized by different time and space warp factors. The main feature of these models is that 4D Lorentz symmetry is violated for fields which propagate in the bulk, such as gravitons. In this paper we examine the case of bulk photons in asymmetrically warped brane models. Although our results are general, we examine here two specific but characteristic solutions: 1) AdS-Schwarzschild 5D Black Hole solution and 2) AdS-Reissner Nordstrom 5D Black Hole solution. We show that the standard Lorentz invariant dispersion relation for 4D photons is corrected by nonlinear terms which lead to an Energy-dependent speed of light. Specifically, we obtain a sub-luminous Energy-dependent refractive index of the form n_{eff}(\\omega)=1+c_{G} \\omega^2, where \\omega is the energy of the photon, and the factor c_G is always positive and depends on the free parameters of the model. Finally, comparing the results with recent data from the MAGIC Telescope, claiming a delayed arrival of photons from the Active Galactic Nucleus of Mk501, we impose concrete restrictions to the two sets of models examined in this work. We shall also discuss briefly other possible astrophysical constraints on our models.
Classical Symmetries of Some Two-Dimensional Models
John H. Schwarz
1995-03-27
It is well-known that principal chiral models and symmetric space models in two-dimensional Minkowski space have an infinite-dimensional algebra of hidden symmetries. Because of the relevance of symmetric space models to duality symmetries in string theory, the hidden symmetries of these models are explored in some detail. The string theory application requires including coupling to gravity, supersymmetrization, and quantum effects. However, as a first step, this paper only considers classical bosonic theories in flat space-time. Even though the algebra of hidden symmetries of principal chiral models is confirmed to include a Kac--Moody algebra (or a current algebra on a circle), it is argued that a better interpretation is provided by a doubled current algebra on a semi-circle (or line segment). Neither the circle nor the semi-circle bears any apparent relationship to the physical space. For symmetric space models the line segment viewpoint is shown to be essential, and special boundary conditions need to be imposed at the ends. The algebra of hidden symmetries also includes Virasoro-like generators. For both principal chiral models and symmetric space models, the hidden symmetry stress tensor is singular at the ends of the line segment.
Belavin, Alexander
2015-01-01
The fermionic NSR string possesses a hidden N = 2 superconformal algebra on the world-sheet. In this work, we show how to use an isomorphism of this algebra, the so-called spectral flow, for construction of a subspace of physical states of the string, on which space-time supersymmetry acts. This construction is an alternative to the GSO-projection in string theory.
Sujan Sengupta
1998-01-29
The ohmic decay of magnetic fields confined within the crust of neutron stars is considered by incorporating both the effect of neutron star cooling and the effect of space-time curvature produced by the intense gravitational field of the star. For this purpose a stationary and static gravitational field has been considered with the standard as well as the accelerated cooling models of neutron stars. It is shown that general relativistic effect reduces the magnetic field decay rate substantially. At the late stage of evolution when the field decay is mainly determined by the impurity-electron scattering, the effect of space-time curvature suppresses the role of the impurity content significantly and reduces the decay rate by more than an order of magnitude. Even with a high impurity content the decay rate is too low to be of observational interest if the accelerated cooling model along with the effect of space-time curvature is taken into account. It is, therefore, pointed out that if a decrease in the magnetic field strength by more than two orders of magnitude from its initial value is detected by observation then the existence of quark in the core of the neutron star would possibly be ruled out.
Yandell, Brian S.
Space-Time Modelling with Long-Memory Dependence: Assessing Ireland's Wind Power Resource Author the long termaverage power output froma wind turbinegenerator at a site forwhich few data on wind speeds and Conditions #12;Appl. Statist.(1989) 38, No. 1, pp. 1-50 Space-timeModellingwithLong-memory Dependence:AssessingIreland'sWind
Discrete multivariate distributions
Oleg Yu. Vorobyev; Lavrentiy S. Golovkov
2011-02-22
This article brings in two new discrete distributions: multidimensional Binomial distribution and multidimensional Poisson distribution. Those distributions were created in eventology as more correct generalizations of Binomial and Poisson distributions. Accordingly to eventology new laws take into account full distribution of events. Also, in article its characteristics and properties are described
Sekhar Chivukula
2010-01-08
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.
Partial Dynamical Symmetry as an Intermediate Symmetry Structure
A. Leviatan
2003-05-06
We introduce the notion of a partial dynamical symmetry for which a prescribed symmetry is neither exact nor completely broken. We survey the different types of partial dynamical symmetries and present empirical examples in each category.
R. B. Burston; A. W. C. Lun
2007-08-14
We use the, covariant and gauge-invariant, 1+1+2 formalism developed by Clarkson and Barrett, and develop new techniques, to decouple electromagnetic (EM) perturbations on arbitrary locally rotationally symmetric (LRS) space-times. Ultimately, we derive 3 decoupled complex equations governing 3 complex scalars. One of these is a new Regge-Wheeler (RW) equation generalized for LRS space-times, whereas the remaining two are new generalizations of the Bardeen-Press (BP) equations. This is achieved by first using linear algebra techniques to rewrite the first-order Maxwell equations in a new complex 1+1+2 form which is conducive to decoupling. This new complex system immediately yields the generalized RW equation, and furthermore, we also derive a decoupled equation governing a newly defined complex EM 2-vector. Subsequently, a further decomposition of the 1+1+2 formalism into a 1+1+1+1 formalism is developed, allowing us to decompose the complex EM 2-vector, and its governing equations, into spin-weighted scalars, giving rise to the generalized BP equations.
Neutrino masses and mixing: a flavour symmetry roadmap
S. Morisi; J. W. F. Valle
2012-06-28
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.
Neutrino masses and mixing: a flavour symmetry roadmap
Morisi, S
2012-01-01
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.
Ground Ring of Alpha-Symmetries and Sequence of RNS String Theories
Dimitri Polyakov
2009-06-03
We construct a sequence of nilpotent BRST charges in RNS superstring theory, based on new gauge symmetries on the worldsheet, found in this paper. These new local gauge symmetries originate from the global nonlinear space-time $\\alpha$-symmetries, shown to form a noncommutative ground ring in this work. The important subalgebra of these symmetries is $U(3)\\times{X_6}$, where $X_6$ is solvable Lie algebra consisting of 6 elements with commutators reminiscent of the Virasoro type. We argue that the new BRST charges found in this work describe the kinetic terms in string field theories around curved backgrounds of the $AdS\\times{CP}_n$-type, determined by the geometries of hidden extra dimensions induced by the global $\\alpha$-generators. The identification of these backgrounds is however left for the work in progress.
Ground Ring of Alpha-Symmetries and Sequence of RNS String Theories
Polyakov, Dimitri
2009-01-01
We construct a sequence of nilpotent BRST charges in RNS superstring theory, based on new gauge symmetries on the worldsheet, found in this paper. These new local gauge symmetries originate from the global nonlinear space-time $\\alpha$-symmetries, shown to form a noncommutative ground ring in this work. The important subalgebra of these symmetries is $U(3)\\times{X_6}$, where $X_6$ is solvable Lie algebra consisting of 6 elements with commutators reminiscent of the Virasoro type. We argue that the new BRST charges found in this work describe the kinetic terms in string field theories around curved backgrounds of the $AdS\\times{CP}_n$-type, determined by the geometries of hidden extra dimensions induced by the global $\\alpha$-generators. The identification of these backgrounds is however left for the work in progress.
Dilaton: Saving Conformal Symmetry
Frederic Gretsch; Alexander Monin
2013-08-18
The characteristic feature of the spontaneous symmetry breaking is the presence of the Goldstone mode(s). For the conformal symmetry broken spontaneously the corresponding Goldstone boson is the dilaton. Coupling an arbitrary system to the dilaton in a consistent (with quantum corrections) way has certain difficulties due to the trace anomaly. In this paper we present the approach allowing for an arbitrary system without the gravitational anomaly to keep the dilaton massless at all orders in perturbation theory, i.e. to build a theory with conformal symmetry broken spontaneously.
John H. Schwarz
1995-03-20
A brief review of the status of duality symmetries in string theory is presented. The evidence is accumulating rapidly that an enormous group of duality symmetries, including perturbative T dualities and non-perturbative S-dualities, underlies string theory. It is my hope that an understanding of these symmetries will suggest the right way to formulate non-perturbative string theory. Whether or not this hope is realized, it has already been demonstrated that this line of inquiry leads to powerful new tools for understanding gauge theories and new evidence for the uniqueness of string theory, as well as deep mathematical results.
Cormac Breen; Adrian C. Ottewill
2011-12-13
We consider a quantum field which is in a Hartle-Hawking state propagating in a spherically symmetric black hole space-time. We calculate the components of the stress tensor, renormalized using the Hadamard form of the Green's function, in the exterior region of this space-time. We then specialize these results to the case of the `lukewarm' Riessner-Nordstrom-de Sitter black hole.
Counting Problems involving Symmetry
Donu Arapura
2013-04-12
Group theory can be applied to counting problems invloving symmetry. Here ... problem is to count the set of orbits H/S3. ... a partition of G. By corollary 3.10,.
Counting Problems involving Symmetry*
Group theory can be applied to counting problems invloving symmetry. Here ... problem is to count the set of orbits H/S3. .... a partition of G. By corollary 2.3,.
Polymer quantization and Symmetries
Ghanashyam Date; Nirmalya Kajuri
2013-02-24
Polymer quantization was discovered during the construction of Loop Quantum Cosmology. For the simplest quantum theory of one degree of freedom, the implications for dynamics were studied for the harmonic oscillator as well as some other potentials. For more degrees of freedom, the possibility of continuous, kinematic symmetries arises. While these are realised on the Hilbert space of polymer quantum mechanics, their infinitesimal versions are not supported. For an invariant Hamiltonian, these symmetry realizations imply infinite degeneracy suggesting that the symmetry should be spontaneously or explicitly broken. The estimation of symmetry violations in some cases have been analysed before. Here we explore the alternative of shifting the arena to the distributional states. We discuss both the polymer quantum mechanics case as well as polymer quantized scalar field.
Discrete Fracture Reservoir Simulation
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
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 Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit theCovalentLaboratory | National NuclearDiscoveringDiscrete Fracture Reservoir
Discrete Probability Distributions
Stewart, William J.
, 2, . . . , n, the moments of the discrete uniform distribution are given by E[Xk ] = nX i=1 ik /n. In particular, E[X] = nX i=1 i/n = 1 n nX i=1 i = 1 n n(n + 1) 2 = n + 1 2 , and, using the well-known formula for the sum of the squares of the first n integers, E[X2 ] = nX i=1 i2 /n = 1 n nX i=1 i2 = 1 n n(n + 1)(2n
Sawa Manoff
2003-09-09
The notions of centrifugal (centripetal) and Coriolis velocities and accelerations are introduced and considered in spaces with affine connections and metrics used as models of space or of space-time. It is shown that these types of velocities and accelerations are generated by the relative motions between mass elements in a continuous media or of particles. The velocities and accelerations are closely related to the kinematic characteristics of the relative velocity and of the relative acceleration. The relation between the centrifugal (centripetal) velocity and the Hubble law is found. The centrifugal (centripetal) acceleration could be interpreted as gravitational acceleration as it has been done in the Einstein theory of gravitation. This fact could be used as a basis for working out of new gravitational theories in spaces with affine connections and metrics.
A multi-term solution of the space-time Boltzmann equation for electrons in gaseous and liquid Argon
Boyle, G J; Tattersall, W J; McEachran, R P; White, R D
2015-01-01
In a recent paper [1] the scattering and transport of excess electrons in liquid argon in the hydrodynamic regime was investigated, generalizing the seminal works of Lekner and Cohen [2,3] with modern scattering theory techniques and kinetic theory. In this paper, the discussion is extended to the non-hydrodynamic regime through the development of a full multi-term space-time solution of Boltzmann's equation for electron transport in gases and liquids using a novel operator-splitting method. A Green's function formalism is considered that enables flexible adaptation to various experimental systems. The spatio-temporal evolution of electrons in liquids in the hydrodynamic regime is studied for a benchmark model Percus-Yevick liquid as well as for liquid argon. The temporal evolution of Franck-Hertz oscillations are observed for liquids, with striking differences in the spatio-temporal development of the velocity distribution function components between the uncorrelated gas and true liquid approximations in arg...
Gauge symmetry breaking in orbifold model building
Michele Trapletti
2006-11-02
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.
Thermodynamics of discrete quantum processes
Janet Anders; Vittorio Giovannetti
2012-11-01
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.
Constucting Discrete KSurfaces Ivan Sterling
Sterling, Ivan
Constucting Discrete KSurfaces Ivan Sterling (joint work with Tim Ho#mann, and Ulrich Pinkall) Old it is possible to find other examples (FIGURE 4). 2 #12; Figure 4. Ho#manSterling Discrete KSurface 4. Computer and examples can be found at www.jreality.de. References [1] G.T. Bennett, A new mechanism, Engineering 76
Thomas D. Cohen
2009-11-16
These lectures discuss the question of whether a key feature is seen in hadron spectroscopy--the near degeneracy of hadrons with different parity and/or spin. It has been conjectured that this is due to an effective restoration of chiral symmetry. The conjecture is that while these states are, of course, in the symmetry-broken (Nambu-Goldstone) phase, as one goes higher in the spectrum the states become progressively less sensitive to the dynamics of chiral symmetry breaking. These lectures discuss the current status of this conjecture. The motivations for the conjecture are discussed, as is evidence--both theoretical and experimental--in its favor. Possible alternative explanations for the data are also discussed.
David Brown
2008-08-19
The BSSN (Baumgarte-Shapiro-Shibata-Nakamura) formulation of the Einstein evolution equations is written in spherical symmetry. These equations can be used to address a number of technical and conceptual issues in numerical relativity in the context of a single Schwarzschild black hole. One of the benefits of spherical symmetry is that the numerical grid points can be tracked on a Kruskal--Szekeres diagram. Boundary conditions suitable for puncture evolution of a Schwarzschild black hole are presented. Several results are shown for puncture evolution using a fourth--order finite difference implementation of the equations.
I. de Medeiros Varzielas
2015-10-08
CP-odd invariants, independent of basis and valid for any choice of CP transformation are a powerful tool in the study of CP. They are particularly convenient to study the CP properties of models with family symmetries. After interpreting the consequences of adding specific CP symmetries to a Lagrangian invariant under $\\Delta(27)$, I use the invariant approach to systematically study Yukawa-like Lagrangians with an increasing field content in terms of $\\Delta(27)$ representations. Included in the Lagrangians studied are models featuring explicit CP violation with calculable phases (referred to as explicit geometrical CP violation) and models that automatically conserve CP, despite having all the $\\Delta(27)$ representations.
Eugene V. Stefanovich
2015-02-16
This book is an attempt to build a consistent relativistic quantum theory of interacting particles. In the first part of the book "Quantum electrodynamics" we follow rather traditional approach to particle physics. Our discussion proceeds systematically from the principle of relativity and postulates of quantum measurements to the renormalization in quantum electrodynamics. In the second part of the book "Quantum theory of particles" this traditional approach is reexamined. We find that formulas of special relativity should be modified to take into account particle interactions. We also suggest reinterpreting quantum field theory in the language of physical "dressed" particles. This formulation eliminates the need for renormalization and opens up a new way for studying dynamical and bound state properties of quantum interacting systems. The developed theory is applied to realistic physical objects and processes including the energy spectrum of the hydrogen atom, the decay law of moving unstable particles, and the electric field of relativistic electron beams. These results force us to take a fresh look at some core issues of modern particle theories, in particular, the Minkowski space-time unification, the role of quantum fields and renormalization as well as the alleged impossibility of action-at-a-distance. A new perspective on these issues is suggested. It can help to solve the old problem of theoretical physics -- a consistent unification of relativity and quantum mechanics.
John H. Schwarz
1992-09-29
The heterotic string compactified on a six-torus is described by a low-energy effective action consisting of N=4 supergravity coupled to N=4 super Yang-Mills, a theory that was studied in detail many years ago. By explicitly carrying out the dimensional reduction of the massless fields, we obtain the bosonic sector of this theory. In the Abelian case the action is written with manifest global $O(6,6+n)$ symmetry. A duality transformation that replaces the antisymmetric tensor field by an axion brings it to a form in which the axion and dilaton parametrize an $SL(2,R)/SO(2)$ coset, and the equations of motion have $SL(2,R)$ symmetry. This symmetry, which combines Peccei--Quinn translations with Montonen--Olive duality transformations, has been exploited in several recent papers to construct black hole solutions carrying both electric and magnetic charge. Our purpose is to explore whether, as various authors have conjectured, an $SL(2,Z)$ subgroup could be an exact symmetry of the full quantum string theory. If true, this would be of fundamental importance, since this group transforms the dilaton nonlinearly and can relate weak and strong coupling.
Discrete generalized multigroup theory and applications
Zhu, Lei, Ph. D. Massachusetts Institute of Technology
2012-01-01
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 ...
Time-space symmetry as a solution to the mass hierarchy of charged lepton generations
Vo Van Thuan
2015-07-27
Based on an extended time-space symmetry, a cylindrical model of gravitational geometrical dynamics with two time-like extra-dimensions leads to a microscopic geodesic description of the curved space-time. Due to interaction of a Higgs-like cosmological potential with individual space-time fluctuations, the original time-space symmetry is spontaneously broken, inducing a strong time-like curvature and a weak space-like deviation curve. As a result, the basic Klein-Gordon-Fock equation of a free massive elementary particle was derived, which implies a duality between the quantum mechanics equation and a microscopic geodesic description in the frame of general relativity. Consequently, Heisenberg inequalities are determined explicitly by the space-time curvatures. Moreover, extending curvatures to higher time-like dimensional hyper-spherical surfaces than one of the basic common cylindrical configuration, we found reasonable mass ratios of all charged leptons and succeeded to fix the number of their generations to be three. Following to concepts of the standard cosmological model, a possible experimental verification of mass ratio variation is proposed.
Time-space symmetry as a solution to the mass hierarchy of charged lepton generations
Van Thuan, Vo
2015-01-01
Based on an extended time-space symmetry, a cylindrical model of gravitational geometrical dynamics with two time-like extra-dimensions leads to a microscopic geodesic description of the curved space-time. Due to interaction of a Higgs-like cosmological potential with individual space-time fluctuations, the original time-space symmetry is spontaneously broken, inducing a strong time-like curvature and a weak space-like deviation curve. As a result, the basic Klein-Gordon-Fock equation of a free massive elementary particle was derived, which implies a duality between the quantum mechanics equation and a microscopic geodesic description in the frame of general relativity. Consequently, Heisenberg inequalities are determined explicitly by the space-time curvatures. Moreover, extending curvatures to higher time-like dimensional hyper-spherical surfaces than one of the basic common cylindrical configuration, we found reasonable mass ratios of all charged leptons and succeeded to fix the number of their generations...
Gravity from Lorentz Symmetry Violation
Potting, Robertus [CENTRA, FCT, University of the Algarve, 8005-139 Faro (Portugal); Physics Department, FCT, University of the Algarve, 8005-139 Faro (Portugal)
2006-06-19
In general relativity, the masslessness of gravitons can be traced to symmetry under diffeomorphisms. In this talk, we consider another possibility, whereby the masslessness arises from spontaneous violation of Lorentz symmetry.
Finsler manifolds with general symmetries
Latifi, Dariush
2012-01-01
In this paper, we study generalized symmetric Finsler spaces. We first study symmetry preserving diffeomorphisms, then we show that the group of symmetry preserving diffeomorphisms is a transitive Lie transformation group. Finally we give some existence theorems.
The multicomponent 2D Toda hierarchy: Discrete flows and string equations
Manuel Manas; Luis Martinez Alonso; Carlos Alvarez Fernandez
2009-01-21
The multicomponent 2D Toda hierarchy is analyzed through a factorization problem associated to an infinite-dimensional group. A new set of discrete flows is considered and the corresponding Lax and Zakharov--Shabat equations are characterized. Reductions of block Toeplitz and Hankel bi-infinite matrix types are proposed and studied. Orlov--Schulman operators, string equations and additional symmetries (discrete and continuous) are considered. The continuous-discrete Lax equations are shown to be equivalent to a factorization problem as well as to a set of string equations. A congruence method to derive site independent equations is presented and used to derive equations in the discrete multicomponent KP sector (and also for its modification) of the theory as well as dispersive Whitham equations.
Felix Hovsepian
2007-11-08
The model of the Universe in this paper uses equations of the unperturbed Keplerian motion. They have been updated, complementied and generalized when the solution of these equations is the characteristic function of a random value from the theory of probabilities. Argument of the differential equation in this case is any more time, an interval of time between sections of a random stationary prosess. In this paper this time interval is referred to as flexible (elastic) time due to its many non-trivial properties. It is proved flexible time does not depend on the space which makes invalid the four dimensional space-time concept. The Universe becomes stationary and Eucledian. It is proved: 1. the advavce of Mercury's perihelion versus the predictions in accordance with the universal gravity law results inequality of the coefficients in the correlation equations of Keplerian moution along axes x, y and z; 2. the velocity of propagation of harmonic oscillation in the Uneverse is not constant; 3. long-range interaction, i.e. instantaneous communication between any two points of space in tne Universe is possible; 4. the Universe is a closed-loop informatiom-energy system which revives the nature and acts as a barrier to the second law of thermodynamics where stars are treated as machines which accumulate energy by moving. Physics in the Universe is conceptually different from that of the Earth and, respectively, needs methods of investigation different from the ones which are used today. Numerous astronomical supervision and the researches lead by known astrophysicist N.A.Kozyrev personally or under his management confirm adequacy of the model in the present paper.
Symmetry Energy in Nuclear Surface
Pawel Danielewicz; Jenny Lee
2008-12-25
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.
Common Discrete Distributions Statistics 104
Irwin, Mark E.
must be all 1, so it is omitted. Discrete Distributions 4 #12;H HHH HHH HH k p 0.01 0.05 0.10 0.20 0
Discrete geodesics and cellular automata
Pablo Arrighi; Gilles Dowek
2015-07-24
This paper proposes a dynamical notion of discrete geodesics, understood as straightest trajectories in discretized curved spacetime. The notion is generic, as it is formulated in terms of a general deviation function, but readily specializes to metric spaces such as discretized pseudo-riemannian manifolds. It is effective: an algorithm for computing these geodesics naturally follows, which allows numerical validation---as shown by computing the perihelion shift of a Mercury-like planet. It is consistent, in the continuum limit, with the standard notion of timelike geodesics in a pseudo-riemannian manifold. Whether the algorithm fits within the framework of cellular automata is discussed at length. KEYWORDS: Discrete connection, parallel transport, general relativity, Regge calculus.
Discrete geodesics and cellular automata
Arrighi, Pablo
2015-01-01
This paper proposes a dynamical notion of discrete geodesics, understood as straightest trajectories in discretized curved spacetime. The notion is generic, as it is formulated in terms of a general deviation function, but readily specializes to metric spaces such as discretized pseudo-riemannian manifolds. It is effective: an algorithm for computing these geodesics naturally follows, which allows numerical validation---as shown by computing the perihelion shift of a Mercury-like planet. It is consistent, in the continuum limit, with the standard notion of timelike geodesics in a pseudo-riemannian manifold. Whether the algorithm fits within the framework of cellular automata is discussed at length. KEYWORDS: Discrete connection, parallel transport, general relativity, Regge calculus.
Strong Electroweak Symmetry Breaking
Grinstein, Benjamin
2011-01-01
Models of spontaneous breaking of electroweak symmetry by a strong interaction do not have fine tuning/hierarchy problem. They are conceptually elegant and use the only mechanism of spontaneous breaking of a gauge symmetry that is known to occur in nature. The simplest model, minimal technicolor with extended technicolor interactions, is appealing because one can calculate by scaling up from QCD. But it is ruled out on many counts: inappropriately low quark and lepton masses (or excessive FCNC), bad electroweak data fits, light scalar and vector states, etc. However, nature may not choose the minimal model and then we are stuck: except possibly through lattice simulations, we are unable to compute and test the models. In the LHC era it therefore makes sense to abandon specific models (of strong EW breaking) and concentrate on generic features that may indicate discovery. The Technicolor Straw Man is not a model but a parametrized search strategy inspired by a remarkable generic feature of walking technicolor,...
Symmetries in open quantum dynamics
Thomas F. Jordan
2014-08-20
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.
Exact Dynamical and Partial Symmetries
A. Leviatan
2010-12-15
We discuss a hierarchy of broken symmetries with special emphasis on partial dynamical symmetries (PDS). The latter correspond to a situation in which a non-invariant Hamiltonian accommodates a subset of solvable eigenstates with good symmetry, while other eigenstates are mixed. We present an algorithm for constructing Hamiltonians with this property and demonstrate the relevance of the PDS notion to nuclear spectroscopy, to quantum phase transitions and to mixed systems with coexisting regularity and chaos.
Discrete Hamiltonian for General Relativity
Ziprick, Jonathan
2015-01-01
Beginning from canonical general relativity written in terms of Ashtekar variables, we derive a discrete phase space with a physical Hamiltonian for gravity. The key idea is to define the gravitational fields within a complex of three-dimensional cells such that the dynamics is completely described by discrete boundary variables, and the full theory is recovered in the continuum limit. Canonical quantization is attainable within the loop quantum gravity framework, and we believe this will lead to a promising candidate for quantum gravity.
Discrete Hamiltonian for General Relativity
Jonathan Ziprick; Jack Gegenberg
2015-07-27
Beginning from canonical general relativity written in terms of Ashtekar variables, we derive a discrete phase space with a physical Hamiltonian for gravity. The key idea is to define the gravitational fields within a complex of three-dimensional cells such that the dynamics is completely described by discrete boundary variables, and the full theory is recovered in the continuum limit. Canonical quantization is attainable within the loop quantum gravity framework, and we believe this will lead to a promising candidate for quantum gravity.
Quantum chaos on discrete graphs
Uzy Smilansky
2007-04-26
Adapting a method developed for the study of quantum chaos on {\\it quantum (metric)} graphs \\cite {KS}, spectral $\\zeta$ functions and trace formulae for {\\it discrete} Laplacians on graphs are derived. This is achieved by expressing the spectral secular equation in terms of the periodic orbits of the graph, and obtaining functions which belongs to the class of $\\zeta$ functions proposed originally by Ihara \\cite {Ihara}, and expanded by subsequent authors \\cite {Stark,Sunada}. Finally, a model of "classical dynamics" on the discrete graph is proposed. It is analogous to the corresponding classical dynamics derived for quantum graphs \\cite {KS}.
Strong Electroweak Symmetry Breaking
Benjamin Grinstein
2011-02-19
Models of spontaneous breaking of electroweak symmetry by a strong interaction do not have fine tuning/hierarchy problem. They are conceptually elegant and use the only mechanism of spontaneous breaking of a gauge symmetry that is known to occur in nature. The simplest model, minimal technicolor with extended technicolor interactions, is appealing because one can calculate by scaling up from QCD. But it is ruled out on many counts: inappropriately low quark and lepton masses (or excessive FCNC), bad electroweak data fits, light scalar and vector states, etc. However, nature may not choose the minimal model and then we are stuck: except possibly through lattice simulations, we are unable to compute and test the models. In the LHC era it therefore makes sense to abandon specific models (of strong EW breaking) and concentrate on generic features that may indicate discovery. The Technicolor Straw Man is not a model but a parametrized search strategy inspired by a remarkable generic feature of walking technicolor, that technivector mesons are light, narrow and decay readily into electroweak vector mesons and photons. While walking technicolor is popular among practitioners, alternatives exist and the Straw Man may not lead to their discovery.
Loop quantization of the Gowdy model with local rotational symmetry
de Blas, Daniel Martín; Paw?owski, Tomasz
2015-01-01
We provide a full quantization of the vacuum Gowdy model with local rotational symmetry. We consider a redefinition of the constraints where the Hamiltonian Poisson-commutes with itself. We then apply of the canonical quantization program of loop quantum gravity within an improved dynamics scheme. We identify the exact solutions of the constraints and the physical observables, and we construct the physical Hilbert space. It is remarkable that quantum spacetimes are free of singularities. New quantum observables naturally arising in the treatment partially codify the discretization of the geometry. The preliminary analysis of the asymptotic future/past of the evolution indicates that the existing Abelianization technique needs further refinement.
Meyer, Sebastian; Rössler, Wulf; Held, Leonhard
2015-01-01
Spatio-temporal interaction is inherent to cases of infectious diseases and occurrences of earthquakes, whereas the spread of other events, such as cancer or crime, is less evident. Statistical significance tests of space-time clustering usually assess the correlation between the spatial and temporal (transformed) distances of the events. Although appealing through simplicity, these classical tests do not adjust for the underlying population nor can they account for a distance decay of interaction. We propose to use the framework of an endemic-epidemic point process model to jointly estimate a background event rate explained by seasonal and areal characteristics, as well as a superposed epidemic component representing the hypothesis of interest. We illustrate this new model-based test for space-time interaction by analysing psychiatric inpatient admissions in Zurich, Switzerland (2007-2012). Several socio-economic factors were found to be associated with the admission rate, but there was no evidence of genera...
Alekseev, George A
2015-01-01
The exact solution of Einstein - Maxwell equations for a Schwarzschild black hole immersed in the static spatially homogeneous AdS${}^2\\times\\mathbb{S}^2$ space-time of Bertotti-Robinson magnetic universe is presented. In this solution, the black hole possesses a finite initial boost in the direction of the magnetic field and performs a "geodesic" oscillating motion interacting with the background gravitational and electromagnetic fields.
Adrian C. Ottewill; Peter Taylor
2012-05-24
We derive a closed-form solution for the Green's function for the wave equation of a static (with respect to an undragged, static observer at infinity) scalar charge in the Kerr space-time. We employ our solution to obtain an analytic expression for the self-force on such a charge, comparing our results to those previously obtained using the mode-sum regularization prescription.
Brane World as a Result of Spontaneous Symmetry Breaking
Boris E. Meierovich
2009-10-09
The theories of brane world and multidimensional gravity are widely discussed in the literature in connection with problems of evolution of early Universe, including dark matter and energy. A natural physical concept is that a distinguished surface in the space-time manifold is a topological defect appeared as a result of a phase transition with spontaneous symmetry breaking. The macroscopic theory of phase transitions allows considering the brane world concept self-consistently, even without the knowledge of the nature of physical vacuum. Gravitational properties of topological defects (cosmic strings, monopoles,...) in extra dimensions are studied in General Relativity considering the order parameter as a vector and a multiplet in a plane target space of scalar fields. The common results and differences of these two approaches are analyzed and demonstrated in detail. Among the variety of regular solutions, there are those having brane features, including solutions with multiple branes, as well as the ones of potential interest from the standpoint of the dark matter and hierarchy problems. Regular configurations have a growing gravitational potential and are able to trap the matter on the brane. If the energy of spontaneous symmetry breaking is high, the attracting potential can have several points of minimum. Identical in the uniform bulk spin-less particles, being trapped within the separate points of minimum, acquire different masses and appear to an observer on brane as different particles with integer spins.
Discrete and Hybrid Nonholonomy Antonio Bicchi1
Piccoli, Benedetto
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
PT symmetry and spontaneous symmetry breaking in a microwave billiard
S. Bittner; B. Dietz; U. Guenther; H. L. Harney; M. Miski-Oglu; A. Richter; F. Schaefer
2011-12-02
We demonstrate the presence of parity-time (PT) symmetry for the non-Hermitian two-state Hamiltonian of a dissipative microwave billiard in the vicinity of an exceptional point (EP). The shape of the billiard depends on two parameters. The Hamiltonian is determined from the measured resonance spectrum on a fine grid in the parameter plane. After applying a purely imaginary diagonal shift to the Hamiltonian, its eigenvalues are either real or complex conjugate on a curve, which passes through the EP. An appropriate basis choice reveals its PT symmetry. Spontaneous symmetry breaking occurs at the EP.
Negative Energy Solutions and Symmetries
Burra G. Sidharth
2011-04-01
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.
Dynamical symmetries in nuclear structure
Casten, R.F.
1986-01-01
In recent years the concept of dynamical symmetries in nuclei has witnessed a renaissance of interest and activity. Much of this work has been developed in the context of the Interacting Boson Approximation (or IBA) model. The appearance and properties of dynamical symmetries in nuclei will be reviewed, with emphasis on their characteristic signatures and on the role of the proton-neutron interaction in their formation, systematics and evolution. 36 refs., 20 figs.
Chiral symmetry on the lattice
Michael Creutz
1994-11-18
I review some of the difficulties associated with chiral symmetry in the context of a lattice regulator. I discuss the structure of Wilson Fermions when the hopping parameter is in the vicinity of its critical value. Here one flavor contrasts sharply with the case of more, where a residual chiral symmetry survives anomalies. I briefly discuss the surface mode approach, the use of mirror Fermions to cancel anomalies, and finally speculate on the problems with lattice versions of the standard model.
Enhanced gauge symmetry and winding modes in Double Field Theory
G. Aldazabal; M. Graña; S. Iguri; M. Mayo; C. Nuñez; J. A. Rosabal
2015-10-26
We provide an explicit example of how the string winding modes can be incorporated in double field theory. Our guiding case is the closed bosonic string compactified on a circle of radius close to the self-dual point, where some modes with non-zero winding or discrete momentum number become massless and enhance the $U(1) \\times U(1)$ symmetry to $SU(2) \\times SU(2)$. We compute three-point string scattering amplitudes of massless and slightly massive states, and extract the corresponding effective low energy gauge field theory. The enhanced gauge symmetry at the self-dual point and the Higgs-like mechanism arising when changing the compactification radius are examined in detail. The extra massless fields associated to the enhancement are incorporated into a generalized frame with $\\frac{O(d+3,d+3)}{O(d+3)\\times O(d+3)}$ structure, where $d$ is the number of non-compact dimensions. We devise a consistent double field theory action that reproduces the low energy string effective action with enhanced gauge symmetry. The construction requires a truly non-geometric frame which explicitly depends on both the compact coordinate along the circle and its dual.
Ely, Gregory
2013-01-01
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.
Fluctuating Dimension in a Discrete Model for Quantum Gravity Based on the Spectral Action
De Albuquerque, L C; Teotônio-Sobrinho, P; Albuquerque, Luiz C. de; Lyra, Jorge L. de; Teotonio-Sobrinho, Paulo
2003-01-01
The spectral action of Connes and Chamseddine is used as a starting point to define a discrete model for Euclidean quantum gravity. Instead of summing over ordinary geometries, we consider the sum over generalized geometries where topology, metric and dimension can fluctuate. The model describes the geometry of spaces with a countable number $n$ of points, and is related to the Gaussian unitary ensemble of Hermitian matrices. We show that this simple model has two phases. The expectation value $$, the average number of points in the universe, is finite in one phase and diverges in the other. We compute the critical point as well as the critical exponent of $$. Moreover, the space-time dimension $\\delta$ is a dynamical observable in our model, and plays the role of an order parameter. The computation of $$ is discussed and a lower bound is found, $ > 2$.
Parity-time symmetry broken by point-group symmetry
Fernández, Francisco M. Garcia, Javier
2014-04-15
We discuss a parity-time (PT) symmetric Hamiltonian with complex eigenvalues. It is based on the dimensionless Schrödinger equation for a particle in a square box with the PT-symmetric potential V(x, y) = iaxy. Perturbation theory clearly shows that some of the eigenvalues are complex for sufficiently small values of |a|. Point-group symmetry proves useful to guess if some of the eigenvalues may already be complex for all values of the coupling constant. We confirm those conclusions by means of an accurate numerical calculation based on the diagonalization method. On the other hand, the Schrödinger equation with the potential V(x, y) = iaxy{sup 2} exhibits real eigenvalues for sufficiently small values of |a|. Point group symmetry suggests that PT-symmetry may be broken in the former case and unbroken in the latter one.
Yoon, Joon Sik, 1973-
2005-01-01
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 ...
Ayan Banerjee; Farook Rahaman; Kanti Jotania; Ranjan Sharma; Mosiur Rahaman
2014-12-05
Gravitational analyzes in lower dimensions has become a field of active research interest ever since Banados, Teitelboim and Zanelli (BTZ) (Phys. Rev. Lett. 69, 1849, 1992) proved the existence of a black hole solution in (2 + 1) dimensions. The BTZ metric has inspired many investigators to develop and analyze circularly symmetric stellar models which can be matched to the exterior BTZ metric. We have obtained two new classes of solutions for a (2 + 1)-dimensional anisotropic star in anti-de Sitter background space-time which have been obtained by assuming that the equation of state (EOS) describing the material composition of the star could either be linear or non-linear in nature. By matching the interior solution to the BTZ exterior metric with zero spin, we have demonstrated that the solutions provided here are regular and well-behaved at the stellar interior.
Center symmetry and Hagedorn spectrum
Cohen, Thomas D
2015-01-01
This paper explores the conjecture that large $N_c$ gauge theories have a Hagedorn spectrum, if, and only if, they are confining and posses an explicit or emergent center symmetry. Evidence in support of this conjecture is presented. Many classes of large $N_c$ gauge theories are considered. In all cases, we find that theories for which there exists a strong plausibility argument for a Hagedorn spectrum at large $N_c$ are also believed to be confining and possess either an explicit center symmetric or have a strong plausibility argument for the existence of an emergent center symmetry at large $N_c$. Conversely, all theories we considered which are believed not to have a Hagedorn spectrum at large $N_c$, either were known not to be confining or else were believed to lack an emergent center symmetry. This is consistent with expectations based on the conjecture.
Chiral Symmetry Breaking in Graphene
Gordon W. Semenoff
2011-08-19
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.
An Introduction to Emergent Symmetries
Gomes, Pedro R S
2015-01-01
These are intended to be introductory notes on emergent symmetries, i.e., symmetries which manifest themselves in specific sectors of energy in many systems. The emphasis is on the physical aspects rather than computation methods. We include some elementary background material and proceed to our discussion by examining several interesting problems in field theory, statistical mechanics and condensed matter. These problems illustrate how some important symmetries, such as Lorentz invariance and supersymmetry, usually believed to be fundamental, can arise naturally in low-energy regimes of systems involving a large number of degrees of freedom. The aim is to discuss how these examples could help us to face other complex and fundamental problems.
Effective field theory for spacetime symmetry breaking
Yoshimasa Hidaka; Toshifumi Noumi; Gary Shiu
2014-12-17
We discuss the effective field theory for spacetime symmetry breaking from the local symmetry point of view. By gauging spacetime symmetries, the identification of Nambu-Goldstone (NG) fields and the construction of the effective action are performed based on the breaking pattern of diffeomorphism, local Lorentz, and (an)isotropic Weyl symmetries as well as the internal symmetries including possible central extensions in nonrelativistic systems. Such a local picture distinguishes, e.g., whether the symmetry breaking condensations have spins and provides a correct identification of the physical NG fields, while the standard coset construction based on global symmetry breaking does not. We illustrate that the local picture becomes important in particular when we take into account massive modes associated with symmetry breaking, whose masses are not necessarily high. We also revisit the coset construction for spacetime symmetry breaking. Based on the relation between the Maurer-Cartan one form and connections for spacetime symmetries, we classify the physical meanings of the inverse Higgs constraints by the coordinate dimension of broken symmetries. Inverse Higgs constraints for spacetime symmetries with a higher dimension remove the redundant NG fields, whereas those for dimensionless symmetries can be further classified by the local symmetry breaking pattern.
Exacting N=4 Superconformal Symmetry
Till Bargheer; Niklas Beisert; Wellington Galleas; Florian Loebbert; Tristan McLoughlin
2009-11-02
Tree level scattering amplitudes in N=4 super Yang-Mills theory are almost, but not exactly invariant under the free action of the N=4 superconformal algebra. What causes the non-invariance is the holomorphic anomaly at poles where external particles become collinear. In this paper we propose a deformation of the free superconformal representation by contributions which change the number of external legs. This modified classical representation not only makes tree amplitudes fully invariant, but it also leads to additional constraints from symmetry alone mediating between hitherto unrelated amplitudes. Moreover, in a constructive approach it appears to fully constrain all tree amplitudes when combined with dual superconformal alias Yangian symmetry.
Exacting N=4 Superconformal Symmetry
Bargheer, Till; Galleas, Wellington; Loebbert, Florian; McLoughlin, Tristan
2009-01-01
Tree level scattering amplitudes in N=4 super Yang-Mills theory are almost, but not exactly invariant under the free action of the N=4 superconformal algebra. What causes the non-invariance is the holomorphic anomaly at poles where external particles become collinear. In this paper we propose a deformation of the free superconformal representation by contributions which change the number of external legs. This modified classical representation not only makes tree amplitudes fully invariant, but it also leads to additional constraints from symmetry alone mediating between hitherto unrelated amplitudes. Moreover, in a constructive approach it appears to fully constrain all tree amplitudes when combined with dual superconformal alias Yangian symmetry.
Compact discrete-time chaos generator circuit
Dudek, Piotr
Compact discrete-time chaos generator circuit P. Dudek and V.D. Juncu A three-transistor CMOS circuit is presented, with adjustable nonlinear characteristics, which can be used as a map that generates discrete-time chaotic signals. A method of constructing a chaos generator using two map circuits is also
Quasicrystals with discrete support and spectrum
Nir Lev; Alexander Olevskii
2015-09-08
We proved recently that a measure on R, whose support and spectrum are both uniformly discrete sets, must have a periodic structure. Here we show that this is not the case if the support and the spectrum are just discrete closed sets.
Quantum Walks and discrete Gauge Theories
Pablo Arnault; Fabrice Debbasch
2015-10-19
A particular example is produced to prove that quantum walks can be used to simulate full-fledged discrete gauge theories. A new family of $(1 + 2)$-dimensional walks is introduced and its continuous limit is shown to coincide with the dynamics of a Dirac fermion coupled to arbitrary electromagnetic fields. The electromagnetic interpretation is extended beyond the continuous limit by proving that these DTQWs exhibit an exact discrete local $U(1)$ gauge invariance and possess a discrete gauge-invariant conserved current. A discrete gauge-invariant electromagnetic field is also constructed and that field is coupled to the conserved current by a discrete generalization of Maxwell equations. The dynamics of the DTQWs under crossed electric and magnetic fields is finally explored outside the continuous limit by numerical simulations. Bloch oscillations and the so-called ${\\bf E} \\times {\\bf B}$ drift are recovered in the weak-field limit. Localization is observed for some values of the gauge fields.
Reciprocal Symmetry and Classical Discrete Oscillator Incorporating Half-Integral Energy Levels
Mushfiq Ahmad
2007-04-02
Classical oscillator differential equation is replaced by the corresponding (finite time) difference equation. The equation is, then, symmetrized so that it remains invariant under the change d going to -d, where d is the smallest span of time. This symmetric equation has solutions, which come in reciprocally related pairs. One member of a pair agrees with the classical solution and the other is an oscillating solution and does not converge to a limit as d goes to 0. This solution contributes to oscillator energy a term which is a multiple of half-integers.
(Small) Resonant non-Gaussianities: Signatures of a Discrete Shift Symmetry
Office of Scientific and Technical Information (OSTI)
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 Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield Municipal GasAdministrationTechnicalTechnicalScience.gov App Findin the Effective Field Theory of
(Small) Resonant non-Gaussianities: Signatures of a Discrete Shift Symmetry
Office of Scientific and Technical Information (OSTI)
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 Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield MunicipalTechnicalInformation4563 LLNL Small-scale Friction Sensitivityv b,Monitoringin the
(Small) resonant non-gaussianities: signatures of a discrete shift symmetry
Office of Scientific and Technical Information (OSTI)
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 Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield MunicipalTechnicalInformation4563 LLNL Small-scale Friction Sensitivityv b,Monitoringin thein the
Baryon and chiral symmetry breaking
Gorsky, A. [Institute for Theoretical and Experimental Physics (ITEP), Moscow, Russia and Moscow Institute of Physics and Technology (MIPT), Dolgoprudny (Russian Federation); Krikun, A. [NORDITA, KTH Royal Institute of Technology and Stockholm University Stockholm, Sweden and Institute for Theoretical and Experimental Physics (ITEP), Moscow (Russian Federation)
2014-07-23
We briefly review the generalized Skyrmion model for the baryon recently suggested by us. It takes into account the tower of vector and axial mesons as well as the chiral symmetry breaking. The generalized Skyrmion model provides the qualitative explanation of the Ioffe’s formula for the baryon mass.
Partial Dynamical Symmetries in Nuclei
A. Leviatan
2000-07-26
Partial dynamical symmetries (PDS) are shown to be relevant to the interpretation of the $K=0_2$ band and to the occurrence of F-spin multiplets of ground and scissors bands in deformed nuclei. Hamiltonians with bosonic and fermionic PDS are presented.
Neutrino Mixing from CP Symmetry
Peng Chen; Chang-Yuan Yao; Gui-Jun Ding
2015-07-13
The neutrino mass matrix has remnant CP symmetry expressed in terms of the lepton mixing matrix, and vice versa the remnant CP transformations allow us to reconstruct the mixing matrix. We study the scenario that all the four remnant CP transformations are preserved by the neutrino mass matrix. The most general parameterization of remnant CP transformations is presented. The lepton mixing matrix is completely fixed by the remnant CP, and its explicit form is derived. The necessary and sufficient condition for conserved Dirac CP violating phase is found. If the Klein four flavor symmetry generated by the postulated remnant CP transformations arises from a finite flavor symmetry group, the phenomenologically viable lepton flavor mixing would be the trimaximal pattern, both Dirac CP phase $\\delta_{CP}$ and Majorana phase $\\alpha_{31}$ are either $0$ or $\\pi$ while another Majorana phase $\\alpha_{21}$ is a rational multiple of $\\pi$. These general results are confirmed to be true in the case that the finite flavor symmetry group is $\\Delta(6n^2)$.
COHERENT DISCRETE EMBEDDINGS FOR LAGRANGIAN AND HAMILTONIAN SYSTEMS
COHERENT DISCRETE EMBEDDINGS FOR LAGRANGIAN AND HAMILTONIAN SYSTEMS by J. Cresson, I. Greff & C . . ........................................ 6 Part II. Discrete variational embedding of Lagrangian systems . . ...................... 7 4. -- Lagrangian systems, Hamiltonian systems, variational integrators, discrete embeddings, numerical schemes, FEM
Identification and Estimation of a Discrete Game of Complete Information
Bajari, Patrick
We discuss the identification and estimation of discrete games of complete information. Following Bresnahan and Reiss (1990, 1991), a discrete game is a generalization of a standard discrete choice model where utility ...
Ken-ichi Maruno; Gino Biondini
2005-04-09
We present a class of solutions of the two-dimensional Toda lattice equation, its fully discrete analogue and its ultra-discrete limit. These solutions demonstrate the existence of soliton resonance and web-like structure in discrete integrable systems such as differential-difference equations, difference equations and cellular automata (ultra-discrete equations).
Testing Lorentz symmetry with atoms and Light
Neil Russell
2011-09-04
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.
Twisted X-rays: incoming waveforms yielding discrete diffraction patterns for helical structures
Friesecke, Gero; Jüstel, Dominik
2015-01-01
Conventional X-ray methods use incoming plane waves and result in discrete diffraction patterns when scattered at crystals. Here we find, by a systematic method, incoming waveforms which exhibit discrete diffraction patterns when scattered at helical structures. As examples we present simulated diffraction patterns of carbon nanotubes and tobacco mosaic virus. The new incoming waveforms, which we call twisted waves due to their geometric shape, are found theoretically as closed-form solutions to Maxwell's equations. The theory of the ensuing diffraction patterns is developed in detail. A twisted analogue of the Von Laue condition is seen to hold, with the peak locations encoding the symmetry and the helix parameters, and the peak intensities indicating the electronic structure in the unit cell. If suitable twisted X-ray sources can in the future be realized experimentally, it appears from our mathematical results that they will provide a powerful tool for directly determining the detailed atomic structure of ...
A Reflective Symmetry Descriptor Michael Kazhdan,
that it does. The objective of our work is to define a continuous measure of reflective symmetry (over any on the sphere in proportion to the measure of reflective symmetry about the #12;Fig. 1. A visualization vectors on the sphere in proportion to the measure of reflective symmetry about the plane through
The transmission of symmetry in liquid crystals
Jie Xu; Pingwen Zhang
2015-09-22
The existing experiments and simulations suggest that the molecular symmetry is always transmitted to homogeneous phases in liquid crystals. It has been proved for rod-like molecules. We conjecture that it holds for three other symmetries, and prove it for some molecules of these symmetries.
Symmetry in Chinese Arts Yip Lixia, Sabrina
Aslaksen, Helmer
Symmetry in Chinese Arts Done by: Group 3 Lim Li Yan Yip Lixia, Sabrina Lee Weitian, Ivan Zhong Shengmin Goh Yoon Keong 1 #12;2 CONTENTS · Introduction · Symmetry in Chinese Literature · Chinese Paper Cuttings · Symmetry in Chinese buildings · Chinese Music · Conclusion · Bibliography #12;3 Introduction
Partial Dynamical Symmetry in Deformed Nuclei
A. Leviatan
1996-06-23
We discuss the notion of partial dynamical symmetry in relation to nuclear spectroscopy. Explicit forms of Hamiltonians with partial $SU(3)$ symmetry are presented in the framework of the interacting boson model of nuclei. An analysis of the resulting spectrum and electromagnetic transitions demonstrates the relevance of such partial symmetry to the spectroscopy of axially deformed nuclei.
Andrei P. Kirilyuk
2014-05-14
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.
Flavored Peccei-Quinn symmetry
Y. H. Ahn
2015-02-10
In an attempt to uncover any underlying physics in the standard model (SM), we suggest a $\\mu$--$\\tau$ power law in the lepton sector, such that relatively large 13 mixing angle with bi-large ones can be derived. On the basis of this, we propose a neat and economical model for both the fermion mass hierarchy problem of the SM and a solution to the strong CP problem, in a way that no domain wall problem occurs, based on $A_{4}\\times U(1)_{X}$ symmetry in a supersymmetric framework. Here we refer to the global $U(1)_X$ symmetry that can explain the above problems as "flavored Peccei-Quinn symmetry". In the model, a direct coupling of the SM gauge singlet flavon fields responsible for spontaneous symmetry breaking to ordinary quarks and leptons, both of which are charged under $U(1)_X$, comes to pass through Yukawa interactions, and all vacuum expectation values breaking the symmetries are connected each other. So, the scale of Peccei-Quinn symmetry breaking is shown to be roughly located around $10^{12}$ GeV section through its connection to the fermion masses. The model predictions are shown to lie on the testable regions in the very near future through on-going experiments for neutrino oscillation, neutrinoless double beta decay and axion. We examine the model predictions, arisen from the $\\mu$--$\\tau$ power law, on leptonic $CP$ violation, neutrinoless double beta decay and atmospheric mixing angle, and show that the fermion mass and mixing hierarchies are in good agreement with the present data. Interestingly, we show the model predictions on the axion mass $m_a\\simeq2.53\\times10^{-5}$ eV and the axion coupling to photon $g_{a\\gamma\\gamma}\\simeq1.33\\times10^{-15}~{\\rm GeV}^{-1}$. And subsequently the square of the ratio between them is shown to be 1 or 2 orders of magnitude lower than that of the conventional axion model.
Peccei-Quinn Symmetry from Dynamical Supersymmetry Breaking
Harigaya, Keisuke; Schmitz, Kai; Yanagida, Tsutomu T
2015-01-01
The proximity of the Peccei-Quinn scale to the scale of supersymmetry breaking in models of pure gravity mediation hints at a common dynamical origin of these two scales. To demonstrate how to make such a connection manifest, we embed the Peccei-Quinn mechanism into the vector-like model of dynamical supersymmetry breaking a la IYIT. Here, we rely on the anomaly-free discrete Z4R symmetry required in models of pure gravity mediation to solve the mu problem to protect the Peccei-Quinn symmetry from the dangerous effect of higher-dimensional operators. This results in a rich phenomenology featuring a QCD axion with a decay constant of O(10^10) GeV and mixed WIMP/axion dark matter. In addition, exactly five pairs of extra 5 and 5* matter multiplets, directly coupled to the supersymmetry breaking sector and with masses close to the gravitino mass, m3/2 ~ 100 TeV, are needed to cancel the Z4R anomalies.
Peccei-Quinn Symmetry from Dynamical Supersymmetry Breaking
Keisuke Harigaya; Masahiro Ibe; Kai Schmitz; Tsutomu T. Yanagida
2015-05-27
The proximity of the Peccei-Quinn scale to the scale of supersymmetry breaking in models of pure gravity mediation hints at a common dynamical origin of these two scales. To demonstrate how to make such a connection manifest, we embed the Peccei-Quinn mechanism into the vector-like model of dynamical supersymmetry breaking a la IYIT. Here, we rely on the anomaly-free discrete Z4R symmetry required in models of pure gravity mediation to solve the mu problem to protect the Peccei-Quinn symmetry from the dangerous effect of higher-dimensional operators. This results in a rich phenomenology featuring a QCD axion with a decay constant of O(10^10) GeV and mixed WIMP/axion dark matter. In addition, exactly five pairs of extra 5 and 5* matter multiplets, directly coupled to the supersymmetry breaking sector and with masses close to the gravitino mass, m3/2 ~ 100 TeV, are needed to cancel the Z4R anomalies.
Adjoint $SU(5)$ GUT model with $T_{7}$ flavor symmetry
Arbeláez, Carolina; Kovalenko, Sergey; Schmidt, Iván
2015-01-01
We propose an adjoint $SU(5)$ GUT model with a $T_{7}$ family symmetry and an extra $Z_{2}\\otimes Z_{2}^{\\prime }\\otimes Z_{3}\\otimes Z_{4}\\otimes Z_{12}$ discrete group, that successfully describes the prevailing Standard Model (SM) fermion mass and mixing pattern. The observed hierarchy of the charged fermion masses and the quark mixing angles arises from the $Z_{3}\\otimes Z_{4}\\otimes Z_{12}$ symmetry breaking, which occurs near the GUT scale. The light active neutrino masses are generated by type I and type III seesaw mechanisms mediated by the fermionic $SU(5)$ singlet and the adjoint $\\mathbf{24}$-plet. The model predicts the effective Majorana neutrino mass parameter of neutrinoless double beta decay to be $m_{\\beta \\beta }=$ 4 and 50 meV for the normal and the inverted neutrino spectrum, respectively. We construct several benchmark scenarios, which lead to $SU(5)$ gauge coupling unification and are compatible with the known phenomenological constraints originating from the lightness of neutrinos, prot...
Probabilistic Calibration of a Discrete Particle Model
Zhang, Yanbei
2011-10-21
A discrete element model (DEM) capable of reproducing the mechanistic behavior of a triaxial compressive test performed on a Vosges sandstone specimen is presented considering similar experimental testing conditions and ...
Discrete element modelling of cementitious materials
Brown, Nicholas John
2013-07-01
This thesis presents a new bonded particle model that accurately predicts the wideranging behaviour of cementitious materials. There is an increasing use of the Discrete Element Method (DEM) to study the behaviour of ...
ADAPTIVE DISCRETIZATION OF AN INTEGRODIFFERENTIAL EQUATION
Larsson, Stig
ADAPTIVE DISCRETIZATION OF AN INTEGROÂDIFFERENTIAL EQUATION MODELING QUASIÂSTATIC FRACTIONAL ORDER VISCOELASTICITY Klas Adolfsson # Mikael Enelund ## Stig Larsson ### # Department of Applied Mechanics, Chalmers Mechanics, Chalmers University of Technology, SE--412 96 GË?oteborg, Sweden, mikael
Thomas D. Cohen
2014-07-15
SU($N_c$) gauge theories containing matter fields may be invariant under transformations of some subgroup of the $\\mathbb{Z}_{N_c}$ center; the maximum such subgroup is $\\mathbb{Z}_{p}$, with $p$ depending on $N_c$ and the representations of the various matter fields in the theory. Confining SU($N_c$) gauge theories in either 3+1 or 2+1 space-time dimensions and with matter fields in any representation have string tensions for representation $R$ given by $\\sigma_R =\\sigma_f \\, \\, \\frac{p_R (p-p_R) \\, \\, g\\left (p_R (p-p_R) \\right )}{(p-1) \\, \\, g(p -1 )} $ with $p_R={n_R \\, \\rm mod}(p)$, where $\\sigma_f $ is the string tension for the fundamental representation, $g$ is a positive finite function and $n_R$ is the n-ality of $R$. This implies that a necessary condition for a theory in this class to have an area law is invariance of the theory under a nontrivial subgroup of the center. Significantly, these results depend on $p$ regardless of the value of $N_c$.
Energy Levels of "Hydrogen Atom" in Discrete Time Dynamics
Andrei Khrennikov; Yaroslav Volovich
2006-04-27
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.
Energy Levels of "Hydrogen Atom" in Discrete Time Dynamics
Khrennikov, A; Khrennikov, Andrei; Volovich, Yaroslav
2006-01-01
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.
History of electroweak symmetry breaking
T. W. B. Kibble
2015-02-22
In this talk, I recall the history of the development of the unified electroweak theory, incorporating the symmetry-breaking Higgs mechanism, as I saw it from my standpoint as a member of Abdus Salam's group at Imperial College. I start by describing the state of physics in the years after the Second World War, explain how the goal of a unified gauge theory of weak and electromagnetic interactions emerged, the obstacles encountered, in particular the Goldstone theorem, and how they were overcome, followed by a brief account of more recent history, culminating in the historic discovery of the Higgs boson in 2012.
Screw symmetry in columnar crystals
A. Mughal
2013-06-12
We show that the optimal packing of hard spheres in an infinitely long cylinder yields structures characterised by a screw symmetry. Each packing can be assembled by stacking a basic unit cell ad infinitum along the length of the cylinder with each subsequent unit cell rotated by the same twist angle with respect to the previous one. In this paper we quantitatively describe the nature of this screw operation for all such packings in the range 1 <= D/d <= 2.715 and also briefly discuss their helicity.
Progress in Electroweak Symmetry Breaking
Dawson, S
2015-01-01
In this talk, I discuss theoretical advances in understanding the properties of the Higgs boson and the implications for models of electroweak symmetry breaking. I begin by reviewing some of the recent progress in Standard Model calculations for Higgs boson production and decay rates, followed by a lightning tour of the use of effective field theories in the search for new physics in the Higgs sector. I end with a discussion of the complementarity of precision Higgs coupling measurements and direct searches for heavy particles for the discovery of Beyond the Standard Model physics in the electroweak sector.
Dynamics-dependent symmetries in Newtonian mechanics
Peter Holland
2014-09-19
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.
Symmetry and Dirac points in graphene spectrum
Gregory Berkolaiko; Andrew Comech
2015-04-23
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.
Inflation, Symmetry, and B-Modes
Mark P. Hertzberg
2015-07-27
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 invoking 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 appreciable amplitude. 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.
Breaking Parity Symmetry Using Extra Dimensions
R. N. Mohapatra; A. Pérez-Lorenzana
1999-11-17
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.
QCD, Symmetry Breaking and the Random Lattice
Saul D. Cohen
2006-02-15
According to the Nielsen-Ninomiya No-Go theorem, the doubling of fermions on the lattice cannot be suppressed in a chiral theory. Whereas Wilson and staggered fermions suppress doublers with explicit breaking of chiral symmetry, the random lattice does so by spontaneous chiral symmetry breaking even in the free theory. I present results for meson masses, the chiral condensate and fermionic eigenvalues from simulations of quenched QCD on random lattices in four dimensions, focusing on chiral symmetry breaking.
Scars of symmetries in quantum chaos
Delande, D.; Gay, J.C.
1987-10-19
The hydrogen atom in a magnetic field is a classically chaotic Hamiltonian system. The energy-level fluctuations have been shown recently to obey a random-matrix model. Here we go beyond the statistical analysis by studying the destruction of the low-field dynamical symmetries. We especially establish the existence of scars of symmetries in the chaotic regime. The symmetry properties are no longer associated with one given level, but fractalized onto clusters of levels, generating a long-range order.
Contact Symmetries and Hamiltonian Thermodynamics
A. Bravetti; C. S. Lopez-Monsalvo; F. Nettel
2015-02-22
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.
Time-reversal symmetry breaking and the field theory of quantum chaos
Simons, B.D. [Cavendish Laboratory, Madingley Road, Cambridge, CB3 0HE (United Kingdom)] [Cavendish Laboratory, Madingley Road, Cambridge, CB3 0HE (United Kingdom); Agam, O. [NEC Research Institute, 4 Independence Way, Princeton, New Jersey 08540 (United States)] [NEC Research Institute, 4 Independence Way, Princeton, New Jersey 08540 (United States); Andreev, A.V. [Institute for Theoretical Physics, University of California, Santa Barbara, California 93106 (United States)] [Institute for Theoretical Physics, University of California, Santa Barbara, California 93106 (United States)
1997-04-01
Recent studies have shown that the quantum statistical properties of systems which are chaotic in their classical limit can be expressed in terms of an effective field theory. Within this description, spectral properties are determined by low energy relaxation modes of the classical evolution operator. It is in the interaction of these modes that quantum interference effects are encoded. In this paper we review this general approach and discuss how the theory is modified to account for time-reversal symmetry breaking. To keep our discussion general, we will also briefly describe how the theory is modified by the presence of an additional discrete symmetry such as inversion. Throughout, parallels are drawn between quantum chaotic systems and the properties of weakly disordered conductors. {copyright} {ital 1997 American Institute of Physics.}
[Re]constructing Finite Flavour Groups: Horizontal Symmetry Scans from the Bottom-Up
Jim Talbert
2015-01-07
We present a novel procedure for identifying discrete, leptonic flavour symmetries, given a class of unitary mixing matrices. By creating explicit 3D representations for generators of residual symmetries in both the charged lepton and neutrino sector, we reconstruct large(r) non-abelian flavour groups using the GAP language for computational finite algebra. We use experimental data to construct only those generators that yield acceptable (or preferable) mixing patterns. Such an approach is advantageous because it 1) can reproduce known groups from other 'top-down' scans while elucidating their origins from residuals, 2) find new previously unconsidered groups, and 3) serve as a powerful model building tool for theorists wishing to explore exotic flavour scenarios. We test our procedure on a generalization of the canonical tri-bimaximal (TBM) form.
Generalized Partial Dynamical Symmetries in Nuclear Spectroscopy
A. Leviatan
2002-10-23
Explicit forms of IBM Hamiltonians with a generalized partial dynamical O(6) symmetry are presented and compared with empirical data in $^{162}$Dy.
Symmetry energy in nuclear density functional theory
W. Nazarewicz; P. -G. Reinhard; W. Satula; D. Vretenar
2013-07-22
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.
Time-reversal symmetry violation in several Lepton-Flavor-Violating processes
Vasquez, Juan Carlos
2015-01-01
We compute a T-odd triple vector correlation for the $\\mu\\rightarrow e\\gamma $ decay and the $\\mu\\rightarrow e$ conversion process. We find simple results in terms of the CP violating phases of the effective Hamiltonians. Then we focus on the minimal Left-Right symmetric extension of the Standard Model, which can lead to an appreciable correlation. We show that under rather general assumptions, this correlation can be used to discriminate between Parity or Charge-conjugation as the discrete Left-Right symmetry.
Time-reversal symmetry violation in several Lepton-Flavor-Violating processes
Juan Carlos Vasquez
2015-04-29
We compute a T-odd triple vector correlation for the $\\mu\\rightarrow e\\gamma $ decay and the $\\mu\\rightarrow e$ conversion process. We find simple results in terms of the CP violating phases of the effective Hamiltonians. Then we focus on the minimal Left-Right symmetric extension of the Standard Model, which can lead to an appreciable correlation. We show that under rather general assumptions, this correlation can be used to discriminate between Parity or Charge-conjugation as the discrete Left-Right symmetry.
Runge-Lenz vector, accidental SU(2) symmetry, and unusual multiplets for motion on a cone
Al-Hashimi, M.H. Wiese, U.-J.
2008-01-15
We consider a particle moving on a cone and bound to its tip by 1/r or harmonic oscillator potentials. When the deficit angle of the cone divided by 2{pi} is a rational number, all bound classical orbits are closed. Correspondingly, the quantum system has accidental degeneracies in the discrete energy spectrum. An accidental SU(2) symmetry is generated by the rotations around the tip of the cone as well as by a Runge-Lenz vector. Remarkably, some of the corresponding multiplets have fractional 'spin' and unusual degeneracies.
Wave Packets in Discrete Quantum Phase Space
Jang Young Bang; Micheal S Berger
2008-11-06
The properties of quantum mechanics with a discrete phase space are studied. The minimum uncertainty states are found, and these states become the Gaussian wave packets in the continuum limit. With a suitably chosen Hamiltonian that gives free particle motion in the continuum limit, it is found that full or approximate periodic time evolution can result. This represents an example of revivals of wave packets that in the continuum limit is the familiar free particle motion on a line. Finally we examine the uncertainty principle for discrete phase space and obtain the correction terms to the continuum case.
Teaching symmetry in the introductory physics curriculum
Hill, C. T.; Lederman, L. M.
2000-01-01
Modern physics is largely defined by fundamental symmetry principles and Noether's Theorem. Yet these are not taught, or rarely mentioned, to beginning students, thus missing an opportunity to reveal that the subject of physics is as lively and contemporary as molecular biology, and as beautiful as the arts. We prescribe a symmetry module to insert into the curriculum, of a week's length.
CP Symmetry in Particle Introduction Results
?umer, Slobodan
CP Symmetry in Particle Physics Introduction Results B-Factory Interpretation Exp. method Future/19Physics in Ljubljana, FMF, July 2011 j j y y #12;Introduction Why CP (A)Symmetry? Introduction Results B anti-baryons annihilated, while 1/109 baryons did not? p y anti-particles #12;Introduction Why CP (A
Symmetry Breaking in Neuroevolution: A Technical Report
Urfalioglu, Onay
2011-01-01
Artificial Neural Networks (ANN) comprise important symmetry properties, which can influence the performance of Monte Carlo methods in Neuroevolution. The problem of the symmetries is also known as the competing conventions problem or simply as the permutation problem. In the literature, symmetries are mainly addressed in Genetic Algoritm based approaches. However, investigations in this direction based on other Evolutionary Algorithms (EA) are rare or missing. Furthermore, there are different and contradictionary reports on the efficacy of symmetry breaking. By using a novel viewpoint, we offer a possible explanation for this issue. As a result, we show that a strategy which is invariant to the global optimum can only be successfull on certain problems, whereas it must fail to improve the global convergence on others. We introduce the \\emph{Minimum Global Optimum Proximity} principle as a generalized and adaptive strategy to symmetry breaking, which depends on the location of the global optimum. We apply the...
Stability of discrete breathers in magnetic metamaterials
Pelinovsky, Dmitry
Stability of discrete breathers in magnetic metamaterials Dmitry Pelinovsky1 and Vassilis Rothos2 1 describing magnetic metamaterials which consist of periodic arrays of split- ring resonators [4, 7]: ¨qn + V criterion to the multi-site breathers in magnetic metamaterials. 2 Formalism In what follows, we shall use
Chow's Team Petri Net Models discrete event
Kaber, David B.
", and "high" plate contents CELISCA: collection of physiology data based on NCSU prototype Output1 CELISCA: collection of physiology data based on New NCSU prototype Output2 #12;k Chow's Team Petri Net Models discrete event stochastic models (set fixed time interval updates
DISCRETE BREATHERS -RECENT RESULTS AND APPLICATIONS
Flach, Sergej
of Complex Systems, NÂ¨othnitzer Str. 38, D-01187 Dresden, Germany E-mail: flach energy thresholds in lattice dimensions d 2, models with ana- lytic solutions and compact solutions the past decade1,2,3 . The discreteness of space - i.e. the usage of a spatial lattice - is crucial
Comment on ``Discrete Boltzmann Equation for Microfluidics''
Luo, Li-Shi
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
On the discrete bicycle transformation S. Tabachnikov
Tabachnikov, Sergei
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
Global discretization of continuous attributes as preprocessing for machine learning
Chmielewski, M. R.; Grzymala-Busse, Jerzy W.
1996-11-01
data sets with discrete attributes. Methods of discretization restricted to single continuous attributes will be called local, while methods that simultaneously convert all continuous attributes will be called global. in this paper, a method...
Defining Employee Perceptions of Discretion: When, Where, and How
Thompson, Rebecca Jean
2013-12-10
The construct employee discretion has been researched under many labels (e.g., flexibility, autonomy). As a result, employee discretion has been operationalized differently across multiple streams of research leading to construct deficiency...
Miki, Hiroshi; Tsujimoto, Satoshi
2011-01-01
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.
Hiroshi Miki; Hiroaki Goda; Satoshi Tsujimoto
2012-02-29
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.
Fractional Topological Phases and Broken Time-Reversal Symmetry...
Office of Scientific and Technical Information (OSTI)
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Growth Mode and Substrate Symmetry Dependent Strain in Epitaxial...
Office of Scientific and Technical Information (OSTI)
Growth Mode and Substrate Symmetry Dependent Strain in Epitaxial Graphene. Citation Details In-Document Search Title: Growth Mode and Substrate Symmetry Dependent Strain in...
Discrete mechanics, optimal control and formation flying spacecraft
Patrick, George
Discrete mechanics, optimal control and formation flying spacecraft Oliver Junge Center-BlÂ¨obaum partially supported by the CRC 376 Oliver Junge Discrete mechanics, optimal control and formation flying spacecraft p.1 #12;Outline mechanical optimal control problem direct discretization of the variational
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)
2014-09-01
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.
Emergent Quantum Mechanics and Emergent Symmetries
Gerard 't Hooft
2007-07-31
Quantum mechanics is 'emergent' if a statistical treatment of large scale phenomena in a locally deterministic theory requires the use of quantum operators. These quantum operators may allow for symmetry transformations that are not present in the underlying deterministic system. Such theories allow for a natural explanation of the existence of gauge equivalence classes (gauge orbits), including the equivalence classes generated by general coordinate transformations. Thus, local gauge symmetries and general coordinate invariance could be emergent symmetries, and this might lead to new alleys towards understanding the flatness problem of the Universe.
Graphene, Lattice QFT and Symmetries
L. B Drissi; E. H Saidi; M. Bousmina
2011-03-07
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.
AVERAGES ALONG POLYNOMIAL SEQUENCES IN DISCRETE NILPOTENT GROUPS: SINGULAR RADON TRANSFORMS
Magyar, Akos
AVERAGES ALONG POLYNOMIAL SEQUENCES IN DISCRETE NILPOTENT GROUPS: SINGULAR RADON TRANSFORMS can consider discrete maximal Radon transforms, which have applications to pointwise ergodic theo- rems, and discrete singular Radon transforms. In this paper we prove L2 boundedness of discrete
Broken symmetries and directed collective energy transport
S. Flach; Y. Zolotaryuk; A. E. Miroshnichenko; M. V. Fistul
2001-10-09
We study the appearance of directed energy current in homogeneous spatially extended systems coupled to a heat bath in the presence of an external ac field E(t). The systems are described by nonlinear field equations. By making use of a symmetry analysis we predict the right choice of E(t) and obtain directed energy transport for systems with a nonzero topological charge Q. We demonstrate that the symmetry properties of motion of topological solitons (kinks and antikinks) are equivalent to the ones for the energy current. Numerical simulations confirm the predictions of the symmetry analysis and, moreover, show that the directed energy current drastically increases as the dissipation parameter $\\alpha$ reduces. Our results generalize recent rigorous theories of currents generated by broken time-space symmetries to the case of interacting many-particle systems.
See the symmetries by Simon Saunders
Saunders, Simon
in Autobiography, in 1934: I heard about and laid hold of the idea of a four dimensional frame for a fresh- perimental physics."(H. G. Wells, "Experiment in Autobiography", 1934, p.172) Wells would have read Symmetry
Space and time from translation symmetry
Albert Schwarz
2009-05-16
We show that the notions of space and time in algebraic quantum field theory arise from translation symmetry if we assume asymptotic commutativity. We argue that this construction can be applied to string theory.
Partial dynamical symmetries in quantum systems
A. Leviatan
2011-12-22
We discuss the the notion of a partial dynamical symmetry (PDS), for which a prescribed symmetry is obeyed by only a subset of solvable eigenstates, while other eigenstates are strongly mixed. We present an explicit construction of Hamiltonians with this property, including higher-order terms, and portray their significance for spectroscopy and shape-phase transitions in nuclei. The occurrence of both a single PDS, relevant to stable structures, and of several PDSs, relevant to coexistence phenomena, are considered.
Enhanced Coset Symmetries and Higher Derivative Corrections
Neil Lambert; Peter West
2006-08-17
After dimensional reduction to three dimensions, the lowest order effective actions for pure gravity, M-theory and the Bosonic string admit an enhanced symmetry group. In this paper we initiate study of how this enhancement is affected by the inclusion of higher derivative terms. In particular we show that the coefficients of the scalar fields associated to the Cartan subalgebra are given by weights of the enhanced symmetry group.
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)
2011-10-01
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.
Scalar Field Theories with Polynomial Shift Symmetries
Tom Griffin; Kevin T. Grosvenor; Petr Horava; Ziqi Yan
2015-08-04
We continue our study of naturalness in nonrelativistic QFTs of the Lifshitz type, focusing on scalar fields that can play the role of Nambu-Goldstone (NG) modes associated with spontaneous symmetry breaking. Such systems allow for an extension of the constant shift symmetry to a shift by a polynomial of degree $P$ in spatial coordinates. These "polynomial shift symmetries" in turn protect the technical naturalness of modes with a higher-order dispersion relation, and lead to a refinement of the proposed classification of infrared Gaussian fixed points available to describe NG modes in nonrelativistic theories. Generic interactions in such theories break the polynomial shift symmetry explicitly to the constant shift. It is thus natural to ask: Given a Gaussian fixed point with polynomial shift symmetry of degree $P$, what are the lowest-dimension operators that preserve this symmetry, and deform the theory into a self-interacting scalar field theory with the shift symmetry of degree $P$? To answer this (essentially cohomological) question, we develop a new graph-theoretical technique, and use it to prove several classification theorems. First, in the special case of $P=1$ (essentially equivalent to Galileons), we reproduce the known Galileon $N$-point invariants, and find their novel interpretation in terms of graph theory, as an equal-weight sum over all labeled trees with $N$ vertices. Then we extend the classification to $P>1$ and find a whole host of new invariants, including those that represent the most relevant (or least irrelevant) deformations of the corresponding Gaussian fixed points, and we study their uniqueness.
The Group of symmetries of a square There are eight symmetries of a square
Smith, Karen E.
The Group of symmetries of a square There are eight symmetries of a square: e = no motion r1) a product of two of its subgroups? 5. How many different (non-isomorphic) groups of order eight can you) a = reflection over anti-diagonal (the line y = -x) Complete the Cayley Table for the dihedral group D4: e r1 r2
Compartmentalization analysis using discrete fracture network models
La Pointe, P.R.; Eiben, T.; Dershowitz, W.; Wadleigh, E.
1997-08-01
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.
Coherence properties of discrete static kinks
H. Landa
2010-02-01
A chain of interacting particles subject also to a nonlinear on-site potential admits stable soliton-like configurations : static kinks. The linear normal-modes around such a kink contain a discrete set of localized, gap-separated modes. Quantization of the Hamiltonian in these modes results in an interacting system of phonons. We investigate numerically the coherence properties of such localized modes at low temperatures using a non-Markovian master equation. We show that low decoherence rates can be achieved in these nonlinear configurations for a surprisingly long time. If realized in the ion trap, kink internal modes may be advantageously used for Quantum Information Processing.
Quantumness of discrete Hamiltonian cellular automata
Hans-Thomas Elze
2014-07-08
We summarize a recent study of discrete (integer-valued) Hamiltonian cellular automata (CA) showing that their dynamics can only be consistently defined, if it is linear in the same sense as unitary evolution described by the Schr\\"odinger equation. This allows to construct an invertible map between such CA and continuous quantum mechanical models, which incorporate a fundamental scale. Presently, we emphasize general aspects of these findings, the construction of admissible CA observables, and the existence of solutions of the modified dispersion relation for stationary states.
Gaussian states and geometrically uniform symmetry
Gianfranco Cariolaro; Roberto Corvaja; Gianfranco Pierobon
2014-10-20
Quantum Gaussian states can be considered as the majority of the practical quantum states used in quantum communications and more generally in quantum information. Here we consider their properties in relation with the geometrically uniform symmetry, a property of quantum states that greatly simplifies the derivation of the optimal decision by means of the square root measurements. In a general framework of the $N$-mode Gaussian states we show the general properties of this symmetry and the application of the optimal quantum measurements. An application example is presented, to quantum communication systems employing pulse position modulation. We prove that the geometrically uniform symmetry can be applied to the general class of multimode Gaussian states.
Collective neutrino oscillations and spontaneous symmetry breaking
Duan, Huaiyu
2015-01-01
Neutrino oscillations in a hot and dense astrophysical environment such as a core-collapse supernova pose a challenging, seven-dimensional flavor transport problem. To make the problem even more difficult (and interesting), neutrinos can experience collective oscillations through nonlinear refraction in the dense neutrino medium in this environment. Significant progress has been made in the last decade towards the understanding of collective neutrino oscillations in various simplified neutrino gas models with imposed symmetries and reduced dimensions. However, a series of recent studies seem to have "reset" this progress by showing that these models may not be compatible with collective neutrino oscillations because the latter can break the symmetries spontaneously if they are not imposed. We review some of the key concepts of collective neutrino oscillations by using a few simple toy models. We also elucidate the breaking of spatial and directional symmetries in these models because of collective oscillation...
Galactic discrete sources of high energy neutrinos
W. Bednarek; G. F. Burgio; T. Montaruli
2004-04-27
We review recently developed models of galactic discrete sources of high energy neutrinos. Some of them are based on a simple rescaling of the TeV $\\gamma$-ray fluxes from recently detected galactic sources, such as, shell-type supernova remnants or pulsar wind nebulae. Others present detailed and originally performed modeling of processes occurring close to compact objects, i.e. neutron stars and low mass black holes, which are supposed to accelerate hadrons close to dense matter and radiation fields. Most of the models considered in this review optimistically assume that the energy content in relativistic hadrons is equal to a significant part of the maximum observable power output in specific sources, i.e. typically $\\sim 10%$. This may give a large overestimation of the neutrino fluxes. This is the case of models which postulate neutrino production in hadron-photon collisions already at the acceleration place, due to the likely $e^\\pm$ pair plasma domination. Models postulating neutrino production in hadron-hadron collisions avoid such problems and therefore seem to be more promising. The neutrino telescopes currently taking data have not detected any excess from discrete sources yet, although some models could already be constrained by the limits they are providing.
Cauchy-perturbative matching reexamined: Tests in spherical symmetry
Zink, Burkhard [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, 85741 Garching (Germany); Pazos, Enrique [Department of Physics and Astronomy, 202 Nicholson Hall, Louisana State University, Baton Rouge, Louisiana 70803 (United States); Center for Computation and Technology, 302 Johnston Hall, Louisana State University, Baton Rouge, Louisiana 70803 (United States); Departamento de Matematica, Universidad de San Carlos de Guatemala, Edificio T4, Facultad de Ingenieria, Ciudad Universitaria Z. 12 (Guatemala); Diener, Peter; Tiglio, Manuel [Department of Physics and Astronomy, 202 Nicholson Hall, Louisana State University, Baton Rouge, Louisiana 70803 (United States); Center for Computation and Technology, 302 Johnston Hall, Louisana State University, Baton Rouge, Louisiana 70803 (United States)
2006-04-15
During the last few years progress has been made on several fronts making it possible to revisit Cauchy-perturbative matching (CPM) in numerical relativity in a more robust and accurate way. This paper is the first in a series where we plan to analyze CPM in the light of these new results. One of the new developments is an understanding of how to impose constraint-preserving boundary conditions (CPBC); though most of the related research has been driven by outer boundaries, one can use them for matching interface boundaries as well. Another front is related to numerically stable evolutions using multiple patches, which in the context of CPM allows the matching to be performed on a spherical surface, thus avoiding interpolations between Cartesian and spherical grids. One way of achieving stability for such schemes of arbitrary high order is through the use of penalty techniques and discrete derivatives satisfying summation by parts (SBP). Recently, new, very efficient and high-order accurate derivatives satisfying SBP and associated dissipation operators have been constructed. Here we start by testing all these techniques applied to CPM in a setting that is simple enough to study all the ingredients in great detail: Einstein's equations in spherical symmetry, describing a black hole coupled to a massless scalar field. We show that with the techniques described above, the errors introduced by Cauchy-perturbative matching are very small, and that very long-term and accurate CPM evolutions can be achieved. Our tests include the accretion and ring-down phase of a Schwarzschild black hole with CPM, where we find that the discrete evolution introduces, with a low spatial resolution of {delta}r=M/10, an error of 0.3% after an evolution time of 1,000,000M. For a black hole of solar mass, this corresponds to approximately 5s, and is therefore at the lower end of timescales discussed e.g. in the collapsar model of gamma-ray burst engines.
Lowest-rank Solutions of Continuous and Discrete Lyapunov ...
2012-10-08
Lyapunov equations are of great importance but generally diffi- cult to achieve in ... of the discrete Lyapunov inequality can be efficiently solved by a linear ...
Lowest-rank Solutions of Continuous and Discrete Lyapunov ...
Ziyan Luo
2012-10-09
Oct 9, 2012 ... Abstract: The low-rank solutions of continuous and discrete Lyapunov equations are of great importance but generally difficult to achieve in ...
Efficient energy stable schemes with spectral discretization in space ...
2012-04-03
We construct energy stable schemes for the time discretization of the highly ... Fundamentally, the gradient energy density loses its convexity (see a proof in the
Dual Transform Domain Echo Canceller for Discrete Multitone Systems
Champagne, Benoît
Dual Transform Domain Echo Canceller for Discrete Multitone Systems Neda Ehtiati and Beno Email:{neda.ehtiati,benoit.champagne}@mcgill.ca Abstract--In communication systems where full
Symmetry violations in nuclear and neutron $?$ decay
K. K. Vos; H. W. Wilschut; R. G. E. Timmermans
2015-09-14
The role of $\\beta$ decay as a low-energy probe of physics beyond the Standard Model is reviewed. Traditional searches for deviations from the Standard Model structure of the weak interaction in $\\beta$ decay are discussed in the light of constraints from the LHC and the neutrino mass. Limits on the violation of time-reversal symmetry in $\\beta$ decay are compared to the strong constraints from electric dipole moments. Novel searches for Lorentz symmetry breaking in the weak interaction in $\\beta$ decay are also included, where we discuss the unique sensitivity of $\\beta$ decay to test Lorentz invariance. We end with a roadmap for future $\\beta$-decay experiments.
Little Flavor and U(2) Family Symmetry
Dorota M. Grabowska; David B. Kaplan
2015-09-28
We examine an effective field theory inspired by Little Flavor that demonstrates a new paradigm for generating quark and lepton masses in which the scale of new flavor physics can be at the few TeV level, and new $Z'$ and $W'$ bosons are predicted. The model possesses an approximate $U(2)^2$ vector symmetry, not the full approximate $U(2)^5$ chiral symmetry of the Standard Model or Minimal Flavor Violation models, yet flavor changing neutral currents are sufficiently suppressed. Additionally, lepton flavor violating processes, such as $\\mu\\to 3e$, lie naturally just below experimental bounds and the down quark mass can be radiatively generated.
Symmetry transformations in Batalin-Vilkovisky formalism
Albert Schwarz
1993-10-19
This short note is closely related to Sen-Zwiebach paper on gauge transformations in Batalin-Vilkovisky theory (hep-th 9309027). We formulate some conditions of physical equivalence of solutions to the quantum master equation and use these conditions to give a very transparent analysis of symmetry transformations in BV-approach. We prove that in some sense every quantum observable (i.e. every even function $H$ obeying $\\Delta_{\\rho}(He^S)=0$) determines a symmetry of the theory with the action functional $S$ satisfying quantum master equation $\\Delta_{\\rho}e^S=0$ \\end
Periodic homogenization and material symmetry in linear elasticity
Mariya Ptashnyk; Brian Seguin
2015-05-07
Here homogenization theory is used to establish a connection between the symmetries of a periodic elastic structure associated with the microscopic properties of an elastic material and the material symmetries of the effective, macroscopic elasticity tensor. Previous results of this type exist but here more general symmetries on the microscale are considered. Using an explicit example, we show that it is possible for a material to be fully anisotropic on the microscale and yet have a nontrivial material symmetry group on the macroscale. Another example demonstrates that not all material symmetries of the macroscopic elastic tensor are generated by symmetries of the periodic elastic structure.
Lepton and Quark Mixing Patterns from Finite Flavor Symmetries
Chang-Yuan Yao; Gui-Jun Ding
2015-05-14
We perform a systematical and analytical study of lepton mixing which can be derived from the subgroups of $SU(3)$ under the assumption that neutrinos are Dirac particles. We find that type D groups can predict lepton mixing patterns compatible with the experimental data at $3\\sigma$ level. The lepton mixing matrix turns out to be of the trimaximal form, and the Dirac CP violating phase is trivial. Moreover, we extend the flavor symmetry to the quark sector. The Cabibbo mixing between the first two generations of quarks can be generated by type D groups. Since all the finite subgroups of $U(3)$ which are not the subgroups of $SU(3)$ have not been classified, an exhaustive scan over all finite discrete groups up to order 2000 is performed with the help of the computer algebra system \\texttt{GAP}. We find that only 90 (10) groups for Dirac (Majorana) neutrinos can generate the lepton mixing angles in the experimentally preferred ranges. The lepton mixing matrix is still the trimaximal pattern and the Dirac CP phase remains trivial. The smallest groups which lead to viable mixing angles are $[162, 10]$, $[162, 12]$ and $[162, 14]$. For quark flavor mixing, the correct order of magnitude of the CKM matrix elements can not be generated. Only the Cabibbo mixing is allowed even if we impose very loose constraints $0.1\\leq|\\left(V_{CKM}\\right)_{12}|\\leq0.3$ and $|\\left(V_{CKM}\\right)_{13}|\\leq|\\left(V_{CKM}\\right)_{23}|right)_{12}|$. The group $\\Delta(6\\cdot7^2)$ can predict a Cabibbo angle $\\theta_q=\\pi/14$ in good agreement with the best fit value. The groups which can give rise to both phenomenologically viable lepton mixing angles and acceptable Cabibbo angle are discussed, and the groups $\\Delta(6\\cdot9^2)$, $[648, 259]$, $[648, 260]$, $[648, 266]$ and $\\Delta(6\\cdot14^2)$ are especially promising.
Mechanical Systems with Symmetry, Variational Principles,
Marsden, Jerrold
Mechanical Systems with Symmetry, Variational Principles, and Integration Algorithms Jerrold E@cds.caltech.edu and Jeffrey M. Wendlandt Mechanical Engineering University of California at Berkeley Berkeley, CA 94720 wents. Birkh¨auser, 1997, 219261. Abstract This paper studies variational principles for mechanical systems
Weyl-Gauge Symmetry of Graphene
Alfredo Iorio
2011-01-19
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.
Symmetries and dynamics in constrained systems
Xavier Bekaert; Jeong-Hyuck Park
2009-04-03
We review in detail the Hamiltonian dynamics for constrained systems. Emphasis is put on the total Hamiltonian system rather than on the extended Hamiltonian system. We provide a systematic analysis of (global and local) symmetries in total Hamiltonian systems. In particular, in analogue to total Hamiltonians, we introduce the notion of total Noether charges. Grassmannian degrees of freedom are also addressed in details.
Information storage capacity of discrete spin systems
Beni Yoshida
2012-12-24
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.
Discrete solitons and vortices on anisotropic lattices
Kevrekidis, P.G. [Department of Mathematics and Statistics, University of Massachusetts, Amherst, Massachusetts 01003-4515 (United States); Frantzeskakis, D.J. [Department of Physics, University of Athens, Panepistimiopolis, Zografos, Athens 15784 (Greece); Carretero-Gonzalez, R. [Nonlinear Dynamical Systems Group, Department of Mathematics and Statistics, and Computational Science Research Center, San Diego State University, San Diego, California 92182-7720 (United States); Malomed, B.A. [Department of Interdisciplinary Studies, School of Electrical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel); Bishop, A.R. [Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
2005-10-01
We consider the effects of anisotropy on solitons of various types in two-dimensional nonlinear lattices, using the discrete nonlinear Schroedinger equation as a paradigm model. For fundamental solitons, we develop a variational approximation that predicts that broad quasicontinuum solitons are unstable, while their strongly anisotropic counterparts are stable. By means of numerical methods, it is found that, in the general case, the fundamental solitons and simplest on-site-centered vortex solitons ('vortex crosses') feature enhanced or reduced stability areas, depending on the strength of the anisotropy. More surprising is the effect of anisotropy on the so-called 'super-symmetric' intersite-centered vortices ('vortex squares'), with the topological charge S equal to the square's size M: we predict in an analytical form by means of the Lyapunov-Schmidt theory, and confirm by numerical results, that arbitrarily weak anisotropy results in dramatic changes in the stability and dynamics in comparison with the degenerate, in this case, isotropic, limit.
Nash Equilibria in Discrete Routing Games with Convex Latency Functions
Mavronicolas, Marios
Nash Equilibria in Discrete Routing Games with Convex Latency Functions Martin Gairing1 , Thomas L 20537, Nicosia CY-1678, Cyprus. mavronic@ucy.ac.cy Abstract. We study Nash equilibria in a discrete, this is the first time that mixed Nash equilibria for routing games have been studied in combination with non
Mechanical Integrators Derived from a Discrete Variational Principle
Marsden, Jerrold
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
Discrete Fourier transform in nanostructures using scattering Michael N. Leuenbergera)
Flatte, Michael E.
Discrete Fourier transform in nanostructures using scattering Michael N. Leuenbergera) and Michael that the discrete Fourier transform DFT can be performed by scattering a coherent particle or laser beam off the initial vector into the two-dimensional potential by means of electric gates, the Fourier
MS Thesis Defense A Combined Discrete-dislocation/Scale-
Grujicic, Mica
MS Thesis Defense A Combined Discrete-dislocation/Scale- dependent Crystal Plasticity Analysis of Deformation and Fracture in Nanomaterials A Combined Discrete-dislocation/Scale- dependent Crystal Plasticity der Giessen, Needleman 1995) Crystal Plasticity Model Results and ComparisonII. Micro-beam Bending
EQUILIBRIUM RECONSTRUCTION FROM DISCRETE MAGNETIC MEASUREMENTS IN A TOKAMAK
Faugeras, Blaise
EQUILIBRIUM RECONSTRUCTION FROM DISCRETE MAGNETIC MEASUREMENTS IN A TOKAMAK Blaise Faugeras (joint of the equilibrium in a Tokamak from discrete magnetic mea- surements. In order to solve this inverse problem we of a plasma in a Tokamak [1]. The state variable of interest in the modelization of such an equilibrium under
Discrete Applied Mathematics 85 (1998) 59-70 MATHEMATICS
Fomin, Fedor V.
1998-01-01
ELSEYIER DISCRETE APPLIED Discrete Applied Mathematics 85 (1998) 59-70 MATHEMATICS Helicopter problem on a graph in which one cop in a helicopter flying from vertex to vertex tries to catch the robber. In each of the following steps, Cop moves (flies by helicopter) to some vertex (not necessarily adjacent
Model Transformation with Hierarchical Discrete-Event Control
Model Transformation with Hierarchical Discrete- Event Control Thomas Huining Feng Electrical, by the author(s). All rights reserved. Permission to make digital or hard copies of all or part of this work permission. #12;Model Transformation with Hierarchical Discrete-Event Control by Huining Feng B.S. (Nanjing
DISCRETE DUALITY FINITE VOLUME SCHEMES FOR DOUBLY NONLINEAR DEGENERATE
operators 17 3.4. Penalization operator 19 3.5. Discrete convection operator 20 3.6. Projection operators establish the existence and uniqueness of entropy solutions. We then turn to the construction and analysis and well-posedness 5 3. Discrete duality finite volume (DDFV) schemes 13 3.1. Construction of "double
Utility Maximization under Model Uncertainty in Discrete Time
Nutz, Marcel
Utility Maximization under Model Uncertainty in Discrete Time Marcel Nutz January 14, 2014 Abstract We give a general formulation of the utility maximization problem under nondominated model uncertainty in discrete time and show that an optimal portfolio exists for any utility function
Discrete curvature and the Gauss-Bonnet theorem
Joakim Arnlind; Jens Hoppe; Gerhard Huisken
2010-01-13
For matrix analogues of embedded surfaces we define discrete curvatures and Euler characteristics, and a non-commutative Gauss--Bonnet theorem is shown to follow. We derive simple expressions for the discrete Gauss curvature in terms of matrices representing the embedding coordinates, and provide a large class of explicit examples illustrating the new notions.
September 2011 Discrete Wheeler-DeWitt Equation
Hamber, Herbert W.
September 2011 Discrete Wheeler-DeWitt Equation Herbert W. Hamber 1 Institut des Hautes Etudes, Cambridge CB3 0JG, United Kingdom. ABSTRACT We present a discrete form of the Wheeler-DeWitt equation, with the solutions to the lattice equations providing a suitable approximation to the continuum wave functional
ISS-Lyapunov Functions for Discontinuous Discrete-Time Systems
Paris-Sud XI, Université de
1 ISS-Lyapunov Functions for Discontinuous Discrete-Time Systems Lars Gr¨une and Christopher M. Kellett Abstract Input-to-State Stability (ISS) and the ISS-Lyapunov function have proved to be useful- ous discrete-time dynamics, we investigate ISS-Lyapunov functions for such systems. ISS-Lyapunov
Institute of Operations Research Discrete Optimization and Logistics
Al Hanbali, Ahmad
Institute of Operations Research Discrete Optimization and Logistics 1 Prof. Dr. Stefan Nickel Health Care Logistics: Overview Health Care Logistics 11/28/2013 #12;Institute of Operations Research Discrete Optimization and Logistics 2 Prof. Dr. Stefan Nickel Health Care Logistics: Overview Health Care
Fiber-Base Duality and Global Symmetry Enhancement
Vladimir Mitev; Elli Pomoni; Masato Taki; Futoshi Yagi
2014-11-10
We show that the 5D Nekrasov partition functions enjoy the enhanced global symmetry of the UV fixed point. The fiber-base duality is responsible for the global symmetry enhancement. For $SU(2)$ with $N_f\\leq 7$ flavors the fiber-base symmetry together with the manifest flavor $SO(2N_f)$ symmetry generate the $E_{N_f+1}$ global symmetry, while in the higher rank case the manifest global symmetry of the two dual theories related by the fiber-base duality map generate the symmetry enhancement. The symmetry enhancement at the level of the partition function is manifest once we chose an appropriate reparametrization for the Coulomb moduli.
Partial Dynamical Symmetry and Anharmonicity in Gamma-Soft Nuclei
A. Leviatan
2009-08-06
Partial dynamical symmetry is shown to be relevant for describing the anharmonicity of excited bands in $^{196}$Pt while retaining solvability and good SO(6) symmetry for the ground band.
Observable to explore high density behaviour of symmetry energy
Aman D. Sood
2011-09-28
We aim to see the sensitivity of collective transverse in-plane flow to symmetry energy at low as well as high densities and also to see the effect of different density dependencies of symmetry energy on the same.
Nuclear symmetry energy at subnormal densities from measured nuclear masses
Min Liu; Ning Wang; Zhuxia Li; Fengshou Zhang
2010-11-17
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.
d li d l iModeling and Solution Issues in Discrete Event Simulationin Discrete Event Simulation
Grossmann, Ignacio E.
// / Flexsim: http://www.flexsim.com/ Witness: http://www.witness-for-simulation.com/ ProModel: httpd li d l iModeling and Solution Issues in Discrete Event Simulationin Discrete Event Simulation of a real system. Simulation helps to predict performance test ideas eliminateSimulation helps to predict
Quasi-Symmetries of Determinantal Point Processes
Alexander I. Bufetov
2014-09-06
The main result of this paper is that determinantal point processes on the real line corresponding to projection operators with integrable kernels are quasi-invariant, in the continuous case, under the group of diffeomorphisms with compact support (Theorem 1.5); in the discrete case, under the group of all finite permutations of the phase space (Theorem 1.7). The Radon-Nikodym derivative is computed explicitly and is given by a regularized multiplicative functional. Theorem 1.5 applies, in particular, to the sine-process and the Bessel point process; Theorem 1.7 to the discrete sine process and the Gamma kernel process. The paper answers a question of Grigori Olshanski.
Space Time Quantization and the Big Bang
B. G. Sidharth
1998-06-21
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.
Hidezumi Terazawa
2015-04-15
Exotic forms of matter such as carbon nanofoams, hexalambdas, super-hypernuclei, strange stars, pentaquarks, color-balls, etc. and their relations to current problems in cosmo-particle physics such as dark matter and energy are discussed in some details. This is an extended version of the invited talk presented at the International Conference on New Trends in High-Energy Physics , Yalta, Crimea(Ukraine), September 10-17, 2005, which has been published in the Proceedings, edited by P.N.Bogolyubov, P.O.Fedosenko, L.L.Jenkovszky, and Yu.A.Karpenko(Bogolyubov Institute for Theoretical Physics, Kiev, 2005). In an extended and up-dated version of the Chapters I and III, entitled "Exotic Nuclei and Strange Stars", which has been published in Nonlinear Phenomena in Complex Systems 18(2015)25-30, new forms of matter such as exotic nuclei and strange stars are discussed in some detail.
Space time and the passage of time
George F. R. Ellis; Rituparno Goswami
2012-08-26
This paper examines the various arguments that have been put forward suggesting either that time does not exist, or that it exists but its flow is not real. I argue that (i) time both exists and flows; (ii) an Evolving Block Universe (`EBU') model of spacetime adequately captures this feature, emphasizing the key differences between the past, present, and future; (iii) the associated surfaces of constant time are uniquely geometrically and physically determined in any realistic spacetime model based in General Relativity Theory; (iv) such a model is needed in order to capture the essential aspects of what is happening in circumstances where initial data does not uniquely determine the evolution of spacetime structure because quantum uncertainty plays a key role in that development. Assuming that the functioning of the mind is based in the physical brain, evidence from the way that the mind apprehends the flow of time prefers this evolving time model over those where there is no flow of time.
Rehabilitating space-times with NUTs
Clément, Gérard; Guenouche, Mourad
2015-01-01
We revisit the Taub-NUT solution of the Einstein equations without time periodicity condition, showing that the Misner string is still fully transparent for geodesics. In this case, analytic continuation can be carried out through both horizons leading to a Hausdorff spacetime without a central singularity, and thus geodesically complete. Furthermore, we show that, in spite of the presence of a region containing closed time-like curves, there are no closed causal {\\em geodesics}. Thus, some longstanding obstructions to accept the Taub-NUT solution as physically relevant are removed.
Rehabilitating space-times with NUTs
Gérard Clément; Dmitri Gal'tsov; Mourad Guenouche
2015-08-30
We revisit the Taub-NUT solution of the Einstein equations without time periodicity condition, showing that the Misner string is still fully transparent for geodesics. In this case, analytic continuation can be carried out through both horizons leading to a Hausdorff spacetime without a central singularity, and thus geodesically complete. Furthermore, we show that, in spite of the presence of a region containing closed time-like curves, there are no closed causal {\\em geodesics}. Thus, some longstanding obstructions to accept the Taub-NUT solution as physically relevant are removed.
Space-Time Insight | Open Energy Information
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 QA:QA J-E-1 SECTION J APPENDIX ECoop Inc JumpHeter BatterySolarfin JumpOpenColorado) JumpSoyminas Biodiesel
Generalized harmonic formulation in spherical symmetry
Evgeny Sorkin; Matthew W. Choptuik
2010-04-30
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.
Combining Pati-Salam and Flavour Symmetries
Thorsten Feldmann; Florian Hartmann; Wolfgang Kilian; Christoph Luhn
2015-06-02
We construct an extension of the Standard Model (SM) which is based on grand unification with Pati-Salam symmetry. The setup is supplemented with the idea of spontaneous flavour symmetry breaking which is mediated through flavon fields with renormalizable couplings to new heavy fermions. While we argue that the new gauge bosons in this approach can be sufficiently heavy to be irrelevant at low energies, the fermionic partners of the SM quarks, in particular those for the third generation, can be relatively light and provide new sources of flavour violation. The size of the effects is constrained by the observed values of the SM Yukawa matrices, but in a way that is different from the standard minimal-flavour violation approach. We determine characteristic deviations from the SM that could eventually be observed in future precision measurements.
Which Chiral Symmetry is Restored in High Temperature QCD?
Claude Bernard; Tom Blum; Carleton DeTar; Steven Gottlieb; Urs M. Heller; James E. Hetrick; K. Rummukainen; R. Sugar; D. Toussaint; Matthew Wingate
1996-11-27
Sigma models for the high temperature phase transition in quantum chromodynamics (QCD) suggest that at high temperature the SU(N_f) x SU(N_f) chiral symmetry becomes exact, but the anomalous axial U(1) symmetry need not be restored. In numerical lattice simulations, traditional methods for detecting symmetry restoration have sought multiplets in the screening mass spectrum. However, these methods were imprecise and the results, so far, incomplete. With improved statistics and methodology, we are now able to offer evidence for a restoration of the SU(2) x SU(2) chiral symmetry just above the crossover, but not of the axial U(1) chiral symmetry.
Sampling of functions with symmetries Frank Natterer
Münster, Westfälische Wilhelms-Universität
. Here, = 2/p with p odd. We call L1 a grid with quarter set-off. We have W1 = 0 0 s , w1 = 0 s/4 , W2 and the grid L1 without the set-off. Then, by the symmetry of g, the scanning can be restricted to j is sampled on the grid L1 = W1 Zn + w1, where W1 is a nonsingular real (n, n)-matrix and w1 an n
Symmetry Algebra of IIB Superstring Scattering
Gordon Chalmers
2005-10-26
The graviton scattering in IIB superstring theory is examined in the context of S-duality and symmetry. There is an algebra that generates all of the terms in the four-point function to any order in derivatives. A map from the algebra to the scattering is given; it suggests the correctness of the full four-point function with the S-duality. The higher point functions are expected to follow a similar pattern.
Wave Equations for Discrete Quantum Gravity
Gudder, Stan
2015-01-01
This article is based on the covariant causal set ($c$-causet) approach to discrete quantum gravity. A $c$-causet $x$ is a finite partially ordered set that has a unique labeling of its vertices. A rate of change on $x$ is described by a covariant difference operator and this operator acting on a wave function forms the left side of the wave equation. The right side is given by an energy term acting on the wave function. Solutions to the wave equation corresponding to certain pairs of paths in $x$ are added and normalized to form a unique state. The modulus squared of the state gives probabilities that a pair of interacting particles is at various locations given by pairs of vertices in $x$. We illustrate this model for a few of the simplest nontrivial examples of $c$-causets. Three forces are considered, the attractive and repulsive electric forces and the strong nuclear force. Large models get much more complicated and will probably require a computer to analyze.
Wave Equations for Discrete Quantum Gravity
Stan Gudder
2015-08-29
This article is based on the covariant causal set ($c$-causet) approach to discrete quantum gravity. A $c$-causet $x$ is a finite partially ordered set that has a unique labeling of its vertices. A rate of change on $x$ is described by a covariant difference operator and this operator acting on a wave function forms the left side of the wave equation. The right side is given by an energy term acting on the wave function. Solutions to the wave equation corresponding to certain pairs of paths in $x$ are added and normalized to form a unique state. The modulus squared of the state gives probabilities that a pair of interacting particles is at various locations given by pairs of vertices in $x$. We illustrate this model for a few of the simplest nontrivial examples of $c$-causets. Three forces are considered, the attractive and repulsive electric forces and the strong nuclear force. Large models get much more complicated and will probably require a computer to analyze.
The Transmission Property of the Discrete Heisenberg Ferromagnetic Spin Chain
Qing Ding; Wei Lin
2008-01-14
We present a mechanism for displaying the transmission property of the discrete Heisenberg ferromagnetic spin chain (DHF) via a geometric approach. By the aid of a discrete nonlinear Schr\\"odinger-like equation which is the discrete gauge equivalent to the DHF, we show that the determination of transmitting coefficients in the transmission problem is always bistable. Thus a definite algorithm and general stochastic algorithms are presented. A new invariant periodic phenomenon of the non-transmitting behavior for the DHF, with a large probability, is revealed by an adoption of various stochastic algorithms.
Switching Between Discrete and Continuous Models To Predict Genetic Activity
Weld, Daniel S.
Molecular biologists use a variety of models when they predict the behavior of genetic systems. A discrete model of the behavior of individual macromolecular elements forms the foundation for their theory of each system. ...
Analysis of steel silo structures on discrete supports
Li, Hongyu
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 ...
Research on Combinatorial Statistics: Crossings and Nestings in Discrete Structures
Poznanovikj, Svetlana
2011-10-21
We study the distribution of combinatorial statistics that exhibit a structure of crossings and nesting in various discrete structures, in particular, in set partitions, matchings, and fillings of moon polyominoes with entries 0 and 1. Let pi and y...
AC transmission system planning choosing lines from a discrete set
Gilbertson, Eric W.
2013-04-24
Transmission system planning (TSP) is a difficult nonlinear optimization problem involving non-convex quadratic terms, as well as discrete variables. We extend prior results for linear relaxations, drawing on a preliminary ...
Design of discrete-time filters for efficient implementation
Wei, Dennis
2011-01-01
The cost of implementation of discrete-time filters is often strongly dependent on the number of non-zero filter coefficients or the precision with which the coefficients are represented. This thesis addresses the design ...
Discrete Feature Approach for Heterogeneous Reservoir Production Enhancement
Dershowitz, William S.; Curran, Brendan; Einstein, Herbert; LaPointe, Paul; Shuttle, Dawn; Klise, Kate
2002-07-26
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.
2-D discrete element modeling of unconsolidated sandstones
Franquet Barbara, Javier Alejandro
2001-01-01
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 ? programming language. The strain-stress behavior of biaxial ...
POLYHEDRAL REPRESENTATION OF DISCRETE MORSE ETHAN D. BLOCH
Bloch, Ethan
POLYHEDRAL REPRESENTATION OF DISCRETE MORSE FUNCTIONS ETHAN D. BLOCH Abstract. It is proved during a sabbatical when parts of this paper were written. 1 #12;2 ETHAN D. BLOCH Forman defines an index
Double-distribution-function discrete Boltzmann model for combustion
Chuandong Lin; Aiguo Xu; Guangcai Zhang; Yingjun Li
2015-11-11
A 2-dimensional discrete Boltzmann model for combustion is presented. Mathematically, the model is composed of two coupled discrete Boltzmann equations for two species and a phenomenological equation for chemical reaction process. Physically, the model is equivalent to a reactive Navier-Stokes model supplemented by a coarse-grained model for the thermodynamic nonequilibrium behaviours. This model adopts 16 discrete velocities. It works for both subsonic and supersonic combustion phenomena with flexible specific heat ratio. To discuss the physical accuracy of the coarse-grained model for nonequilibrium behaviours, three other discrete velocity models are used for comparisons. Numerical results are compared with analytical solutions based on both the first-order and second-order truncations of the distribution function. It is confirmed that the physical accuracy increases with the increasing moment relations needed by nonequlibrium manifestations. Furthermore, compared with the single distribution function model, this model can simulate more details of combustion.
Automatic Performance Optimization of the Discrete Fourier Transform
Franchetti, Franz
Automatic Performance Optimization of the Discrete Fourier Transform on Distributed Memory {franzf,pueschel}@ece.cmu.edu Abstract. This paper introduces a formal framework for automatically. Using a tagging mechanism and formula rewriting, we extend SPIRAL to automatically generate parallelized
Finding discrete logarithms with a set orbit distinguisher
International Association for Cryptologic Research (IACR)
or a prime order 1 #12;subgroup of an elliptic curve group, and a standard assumption in these groups outline algorithms for computing discrete logarithms. The theme in each case is that given a polynomial
Dual Domain Echo Cancellers for Multirate Discrete Multitone Systems
Champagne, Benoît
Dual Domain Echo Cancellers for Multirate Discrete Multitone Systems Neda Ehtiati and Beno Email:{neda.ehtiati, benoit.champagne}@mcgill.ca Abstract--Digital echo cancellers are used in duplex
On the solutions of generalized discrete Poisson Roman Werpachowski
On the solutions of generalized discrete Poisson equation Roman Werpachowski Center for Theoretical of the right-hand side g and will be analyzed elsewhere. 2 #12;2 Uniqueness theorem Theorem 1 Let x : Zd C
Resolution of grain scale interactions using the Discrete Element Method
Johnson, Scott M. (Scott Matthew), 1978-
2006-01-01
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, ...
Direct measurement of yield stress of discrete materials
S. H. Ebrahimnazhad Rahbari; J. Vollmer; S. Herminghaus; M. Brinkmann
2012-06-09
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.
Dirac or inverse seesaw neutrino masses with B – L gauge symmetry and S? flavor symmetry
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Ma, Ernest; Srivastava, Rahul
2015-02-01
Many studies have been made on extensions of the standard model with B – L gauge symmetry. The addition of three singlet (right-handed) neutrinos renders it anomaly-free. It has always been assumed that the spontaneous breaking of B – L is accomplished by a singlet scalar field carrying two units of B – L charge. This results in a very natural implementation of the Majorana seesaw mechanism for neutrinos. However, there exists in fact another simple anomaly-free solution which allows Dirac or inverse seesaw neutrino masses. We show for the first time these new possibilities and discuss an application tomore »neutrino mixing with S? flavor symmetry.« less
Department of Electrical Engineering and Computer Science Discrete Event Systems Group
Tilbury, Dawn
Department of Electrical Engineering and Computer Science 1 Discrete Event Systems Group A Discrete 2000 #12;Department of Electrical Engineering and Computer Science 2 Discrete Event Systems Group of Electrical Engineering and Computer Science 3 Discrete Event Systems Group Requirements for Industrial
Bounds for the price of discrete arithmetic Asian options M. Vanmaele
Vanmaele, Michèle
on discrete averaging which is the normal specification in real contracts. Discrete arithmetic Asian optionsBounds for the price of discrete arithmetic Asian options M. Vanmaele , G. Deelstra , J. Liinev , J.Goovaerts@econ.kuleuven.ac.be, Tel. +32 16 326750. #12;Bounds for the price of discrete arithmetic Asian options Abstract
The Discrete Operator Approach to the Numerical Solution of Partial Differential Equations
The Discrete Operator Approach to the Numerical Solution of Partial Differential Equations James C that performs a cer- tain calculation on a field. A field corresponds to any scalar or vector variable required = Discrete gradient operator I = Discrete integral operator L = Generic operator R = Discrete interpolant
Fundamental Symmetries of the Modified Anyonic Particle
Nejad, Salman Abarghouei; Monemzadeh, Majid
2015-01-01
We try to increase the fundamental symmetries of the anyonic particle with the help of the symplectic formalism of constrained systems and gauging the model. The main idea of this approach is based on the embedding of the model in an extended phase space. After the gauging process had done, we obtain generators of gauge transformations of the model. Finally, by extracting the corresponding Poisson structure of all constraints, we compare the effect of gauging on the the phase spaces, the number of physical degrees of freedom, and canonical structures of both primary and gauged models.
Symmetry Energy as a Function of Density and Mass
Pawel Danielewicz; Jenny Lee
2007-08-21
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.
Lorentz symmetry breaking effects on relativistic EPR correlations
Belich, H; Bakke, K
2015-01-01
Lorentz symmetry breaking effects on relativistic EPR (Einstein-Podolsky-Rosen) correlations are discussed. From the modified Maxwell theory coupled to gravity, we establish a possible scenario of the Lorentz symmetry violation and write an effective metric for the Minkowski spacetime. Then, we obtain the Wigner rotation angle via the Fermi-Walker transport of spinors and consider the WKB ((Wentzel-Kramers-Brillouin) approximation in order to study the influence of Lorentz symmetry breaking effects on the relativistic EPR correlations.
Effect of density dependent symmetry energy on Elliptical flow
Suneel Kumar; Karan Singh Vinayak
2011-08-30
The effect of the density dependent symmetry energy on elliptical flow is studied using isospin-dependent quantum molecular dynamics model(IQMD). We have used the reduced isospin-dependent cross-section with soft equation of state to study the sensitivity of elliptical flow towards symmetry energy. Aim of the present study is to pin down the Elliptical flow for the various forms of the density dependent symmetry energy.
On Flavor Symmetry in Lattice Quantum Chromodynamics
El Hassan Saidi
2012-03-27
Using a well established method to engineer non abelian symmetries in superstring compactifications, we study the link between the point splitting method of Creutz et al of refs [1,2] for implementing flavor symmetry in lattice QCD; and singularity theory in complex algebraic geometry. We show amongst others that Creutz flavors for naive fermions are intimately related with toric singularities of a class of complex Kahler manifolds that are explicitly built here. In the case of naive fermions of QCD$_{2N}$, Creutz flavors are shown to live at the poles of real 2-spheres and carry quantum charges of the fundamental of $[SU(2)]^{2N}$. We show moreover that the two Creutz flavors in Karsten-Wilczek model, with Dirac operator in reciprocal space of the form $i\\gamma_1 F_1+i\\gamma_2 F_2 + i\\gamma_3 F_3+\\frac{i}{\\sin \\alpha}\\gamma_4 F_4$, are related with the small resolution of conifold singularity that live at $\\sin \\alpha =0$. Other related features are also studied.
Heavy-quark symmetry and chiral dynamics
Yan, T. (Institute of Physics, Academia Sinica, Taipei, Taiwan 11529 (Taiwan, Province of China) Floyd R. Newman Laboratory of Nuclear Studies, Cornell University, Ithaca, New York 14853 (United States)); Cheng, H.; Cheung, C.; Lin, G. (Institute of Physics, Academia Sinica, Taipei, Taiwan 11529 (Taiwan, Province of China)); Lin, Y.C. (Physics Department, National Central University, Chung-li, Taiwan 32054 (Taiwan, Province of China)); Yu, H. (Institute of Physics, Academia Sinica, Taipei, Taiwan 11529 (Taiwan, Province of China))
1992-08-01
The flavor and spin symmetry of the heavy quarks and the spontaneously broken approximate SU(3){sub {ital L}}{times} SU(3){sub {ital R}} chiral symmetry of the light quarks are exploited to formulate a theory describing the low-energy interactions of the heavy mesons ({ital Q{bar q}} bound states) and heavy baryons ({ital Qq}{sub 1}{ital q2} bound states) with the Goldstone bosons {pi}, {ital K}, and {eta}. The theory contains only three parameters independent of the number of heavy-quark species involved. They can be determined by the decays {ital D}{sup *}{r arrow}{ital D}+{pi}, {Sigma}{sub {ital c}}{r arrow}{Lambda}{sub {ital c}}+{pi}, and {Sigma}{sub {ital c}}{sup *}{r arrow}{Sigma}{sub {ital c}}+{pi}. Theoretically, these coupling constants are related, through partial conservation of axial-vector current, to the axial charges of the heavy mesons and the heavy baryons. They are all calculable in the nonrelativistic quark model by using the spin wave functions of these particles alone. The theory is applied to strong decays and semileptonic weak decays of the heavy mesons and baryons. The implications are also discussed.
Initial Stress Symmetry and Applications in Elasticity
Artur L. Gower; Pasquale Ciarletta; Michel Destrade
2015-06-16
An initial stress within a solid can arise to support external loads or from processes such as thermal expansion in inert matter or growth and remodelling in living materials. For this reason it is useful to develop a mechanical framework of initially stressed solids irrespective of how this stress formed. An ideal way to do this is to write the free energy density $\\Psi= \\Psi(\\boldsymbol F, \\boldsymbol {\\tau})$ in terms of initial stress $\\boldsymbol \\tau$ and the elastic deformation gradient $\\boldsymbol F$. In this paper we present a new constitutive condition for initially stressed materials, which we call the initial stress symmetry (ISS). We focus on two consequences of this symmetry. First we examine how ISS restricts the free energy density $\\Psi = \\Psi (\\boldsymbol F, \\boldsymbol \\tau) $ and present two examples of $\\Psi (\\boldsymbol F, \\boldsymbol \\tau)$ that satisfy ISS. Second we show that the initial stress can be derived from the Cauchy stress and the elastic deformation gradient. To illustrate we take an example from biomechanics and calculate the optimal Cauchy stress within an artery subjected to internal pressure. We then use ISS to derive the optimal target residual stress for the material to achieve after remodelling.
Symmetries and exact solutions of the rotating shallow water equations
Alexander Chesnokov
2008-08-11
Lie symmetry analysis is applied to study the nonlinear rotating shallow water equations. The 9-dimensional Lie algebra of point symmetries admitted by the model is found. It is shown that the rotating shallow water equations are related with the classical shallow water model with the change of variables. The derived symmetries are used to generate new exact solutions of the rotating shallow equations. In particular, a new class of time-periodic solutions with quasi-closed particle trajectories is constructed and studied. The symmetry reduction method is also used to obtain some invariant solutions of the model. Examples of these solutions are presented with a brief physical interpretation.
Dynamical electroweak symmetry breaking and the top quark
Chivukula, R.S. [Boston Univ., MA (United States)
1997-01-01
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.
SYMMETRY OF THE IBEX RIBBON OF ENHANCED ENERGETIC NEUTRAL ATOM...
Office of Scientific and Technical Information (OSTI)
HELIOSPHERE; INTERSTELLAR SPACE; KEV RANGE; MAGNETIC FIELDS; PLASMA; REFLECTION; SUN; SYMMETRY Word Cloud More Like This Full Text Journal Articles DOI: 10.10880004-637X...
SYMMETRY OF THE IBEX RIBBON OF ENHANCED ENERGETIC NEUTRAL ATOM...
Office of Scientific and Technical Information (OSTI)
HELIOSPHERE; INTERSTELLAR SPACE; KEV RANGE; MAGNETIC FIELDS; PLASMA; REFLECTION; SUN; SYMMETRY The circular ribbon of enhanced energetic neutral atom (ENA) emission...
Symmetry energy at subnuclear densities deduced from nuclear masses
Kazuhiro Oyamatsu; Kei Iida
2010-04-19
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.
Publisher's Note: "Chiral symmetry restoration at large chemical...
Office of Scientific and Technical Information (OSTI)
Publisher's Note: "Chiral symmetry restoration at large chemical potential 2 in strongly coupled SU(N) gauge theories" J. Math. Phys. 54, 122301 (2013) Citation Details...
Are nonlinear discrete cellular automata compatible with quantum mechanics?
Hans-Thomas Elze
2015-05-14
We consider discrete and integer-valued cellular automata (CA). A particular class of which comprises "Hamiltonian CA" with equations of motion that bear similarities to Hamilton's equations, while they present discrete updating rules. The dynamics is linear, quite similar to unitary evolution described by the Schroedinger equation. This has been essential in our construction of an invertible map between such CA and continuous quantum mechanical models, which incorporate a fundamental discreteness scale. Based on Shannon's sampling theory, it leads, for example, to a one-to-one relation between quantum mechanical and CA conservation laws. The important issue of linearity of the theory is examined here by incorporating higher-order nonlinearities into the underlying action. These produce inconsistent nonlocal (in time) effects when trying to describe continuously such nonlinear CA. Therefore, in the present framework, only linear CA and local quantum mechanical dynamics are compatible.
Modeling quasi-lattice with octagonal symmetry
Girzhon, V. V.; Smolyakov, O. V.; Zakharenko, M. I.
2014-11-15
We prove the possibility to use the method of modeling of a quasi-lattice with octagonal symmetry similar to that proposed earlier for the decagonal quasicrystal. The method is based on the multiplication of the groups of basis sites according to specified rules. This model is shown to be equivalent to the method of the periodic lattice projection, but is simpler because it considers merely two-dimensional site groups. The application of the proposed modeling procedure to the reciprocal lattice of octagonal quasicrystals shows a fairly good matching with the electron diffraction pattern. Similarly to the decagonal quasicrystals, the possibility of three-index labeling of the diffraction reflections is exhibited in this case. Moreover, the ascertained ratio of indices provides information on the intensity of diffraction reflections.
Symmetry tests in photo-pion production
Bernstein, A. M.
2013-11-07
Small angle electron scattering with intense electron beams opens up the possibility of performing almost real photon induced reactions with thin, polarized hydrogen and few body targets, allowing for the detection of low energy charged particles. This promises to be much more effective than conventional photon tagging techniques. For photo-pion reactions some fundamental new possibilities include: tests of charge symmetry in the N-N system by measurement of the neutron-neutron scattering length a{sub nn} in the and ggrD ? ?{sup +}nn reaction; tests of isospin breaking due to the mass difference of the up and down quarks; measurements with polarized targets are sensitive to ?N phase shifts and will test the validity of the Fermi-Watson (final state interaction) theorem. All of these experiments will test the accuracy and energy region of validity of chiral effective theories.
Infrared modification of gravity from conformal symmetry
Gegenberg, Jack; Seahra, Sanjeev S
2015-01-01
We reconsider a gauge theory of gravity in which the gauge group is the conformal group SO(4,2) and the action is of the Yang-Mills form, quadratic in the curvature. The resulting gravitational theory exhibits local conformal symmetry and reduces to Weyl-squared gravity under certain conditions. When the theory is linearized about flat spacetime, we find that matter which couples to the generators of special conformal transformations reproduces Newton's inverse square law. Conversely, matter which couples to generators of translations induces a constant and possibly repulsive force far from the source, which may be relevant for explaining the late time acceleration of the universe. The coupling constant of theory is dimensionless, which means that it is potentially renormalizable.
Dark Matter and Gauged Flavor Symmetries
Bishara, Fady; Kamenik, Jernej F; Stamou, Emmanuel; Zupan, Jure
2015-01-01
We investigate the phenomenology of flavored dark matter (DM). DM stability is guaranteed by an accidental ${\\mathcal Z}_3$ symmetry, a subgroup of the standard model (SM) flavor group that is not broken by the SM Yukawa interactions. We consider an explicit realization where the quark part of the SM flavor group is fully gauged. If the dominant interactions between DM and visible sector are through flavor gauge bosons, as we show for Dirac fermion flavored DM, then the DM mass is bounded between roughly $0.5$ TeV and $5$ TeV if the DM multiplet mass is split only radiatively. In general, however, no such relation exists. We demonstrate this using scalar flavored DM where the main interaction with the SM is through the Higgs portal. For both cases we derive constraints from flavor, cosmology, direct and indirect DM detection, and collider searches.
Lepton Flavor Mixing and CP Symmetry
Peng Chen; Cai-Chang Li; Gui-Jun Ding
2014-12-29
The strategy of constraining the lepton flavor mixing from remnant CP symmetry is investigated in a rather general way. The neutrino mass matrix generally admits four remnant CP transformations which can be derived from the measured lepton mixing matrix in the charged lepton diagonal basis. Conversely, the lepton mixing matrix can be reconstructed from the postulated remnant CP transformations. All mixing angles and CP violating phases can be completely determined by the full set of remnant CP transformations or three of them. When one or two remnant CP transformations are preserved, the resulting lepton mixing matrix would depend on three real parameters or one real parameter respectively in addition to the parameters characterizing the remnant CP, and the concrete form of the mixing matrix is presented. The phenomenological predictions for the mixing parameters are discussed. The conditions leading to vanishing or maximal Dirac CP violation are studied.
Development of an Interhemispheric Symmetry Measurement in the Neonatal Brain
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
Symmetry, Fullerenes, Nanotechnology and Other Stuff Virginia Tech
Zhigilei, Leonid V.
Symmetry, Fullerenes, Nanotechnology and Other Stuff H. C. Dorn Virginia Tech Alpha helix Protein and I. Hargittai Visual Symmetry, World Scientific, 2009 #12;Nanotechnology The Big and Small of it Buckyballs and Nanotechnology! #12;Richard Feynman "There's Plenty of Room at the Bottom" Cal Tech, Dec. 29
Symmetry Remnants in the Face of Competing Interactions in Nuclei
Leviatan, A
2015-01-01
Detailed description of nuclei necessitates model Hamiltonians which break most dynamical symmetries. Nevertheless, generalized notions of partial and quasi dynamical symmetries may still be applicable to selected subsets of states, amidst a complicated environment of other states. We examine such scenarios in the context of nuclear shape-phase transitions.
Evolution towards Symmetry Ferdinand Verhulst and Richard Huveneers
Verhulst, Ferdinand
Evolution towards Symmetry Ferdinand Verhulst and Richard Huveneers Mathematisch Instituut those of today and will the laws of tomorrow still be the same? Henri PoincarÂ´e in `The evolution of the laws', Derni`eres PensÂ´ees. Abstract The dynamics of time-dependent evolution towards symmetry
HIDDEN SYMMETRIES OF CYCLIC BRANCHED COVERINGS OF 2-BRIDGE KNOTS
HIDDEN SYMMETRIES OF CYCLIC BRANCHED COVERINGS OF 2-BRIDGE KNOTS MARCO RENI AND ANDREI VESNIN hyperbolic 3-manifolds Mn(K), which are n- fold cyclic branched coverings of 2-bridge knots K. We show the symmetry groups of knots and links (see [BZ], [Ka]). Particularly, the class of 2-bridge knots
Energy Content of Colliding Plane Waves using Approximate Noether Symmetries
M. Sharif; Saira Waheed
2011-09-19
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
Symmetry in CSP solutions Nicoleta Neagu and Boi Faltings
Flener, Pierre
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
Computer aided analysis and synthesis for discrete robust control systems
Setijawan, Bambang
1994-01-01
of an interval discrete system. . 4 Nyquist plot of the system with a constant controller k = -3. . . . . 5 Definition of encirclement. . Page 27 28 30 6 Definition of enclosed points and regions. . 7 Definition of the number of encirclement and enclosure... unstable 1 Re marginally stable Fig. 1. Stability region for discrete time systems A general control system is presented in the following figure, r e + controller C(z) PLANT G(z) Fig. 2. A general form of control systems Any physical process...
Discrete Cosmological Self-Similarity And Delta Scuti Stars
R. L. Oldershaw
2008-10-08
Within the context of a fractal paradigm that emphasizes nature's well-stratified hierarchical organization, the delta Scuti class of variable stars is investigated for evidence of discrete cosmological self-similarity. Methods that were successfully applied to the RR Lyrae class of variable stars are used to identify Atomic Scale analogues to delta Scuti stars and their relevant range of energy levels. The mass, pulsation mode and fundamental oscillation period of a well-studied delta Scuti star are shown to be quantitatively self-similar to the counterpart parameters of a uniquely identified Atomic Scale analogue. Several additional tests confirm the specificity of the discrete fractal relationship.
Methodology for characterizing modeling and discretization uncertainties in computational simulation
ALVIN,KENNETH F.; OBERKAMPF,WILLIAM L.; RUTHERFORD,BRIAN M.; DIEGERT,KATHLEEN V.
2000-03-01
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.
The Nuclear Symmetry Energy in Heavy Ion Collisions
Wolter, Hermann
2015-01-01
In this contribution I discuss the nuclear symmetry energy in the regime of hadronic degrees of freedom. The density dependence of the symmetry energy is important from very low densities in supernova explosions, to the structure of neutron-rich nuclei around saturation density, and to several times saturation density in neutron stars. Heavy ion collisions are the only means to study this density dependence in the laboratory. Numerical simulations of transport theories are used to extract the equation-of-state, and thus also the symmetry energy. I discuss some examples, which relate particularly to the high density symmetry energy, which is of particular interest today. I review the status and point out some open problems in the determination of the symmetry energy in heavy ion collisions.
The Nuclear Symmetry Energy in Heavy Ion Collisions
Hermann Wolter
2015-06-15
In this contribution I discuss the nuclear symmetry energy in the regime of hadronic degrees of freedom. The density dependence of the symmetry energy is important from very low densities in supernova explosions, to the structure of neutron-rich nuclei around saturation density, and to several times saturation density in neutron stars. Heavy ion collisions are the only means to study this density dependence in the laboratory. Numerical simulations of transport theories are used to extract the equation-of-state, and thus also the symmetry energy. I discuss some examples, which relate particularly to the high density symmetry energy, which is of particular interest today. I review the status and point out some open problems in the determination of the symmetry energy in heavy ion collisions.
Light Nuclei and HyperNuclei from Quantum Chromodynamics in the Limit of SU(3) Flavor Symmetry
Beane, S R; Cohen, S D; Detmold, W; Lin, H W; Luu, T C; Orginos, K; Parreno, A; Savage, M J
2013-02-01
The binding energies of a range of nuclei and hypernuclei with atomic number A <= 4 and strangeness |s| <= 2, including the deuteron, di-neutron, H-dibaryon, {sup 3}He, {sub {Lambda}}{sup 3}He, {sub {Lambda}}{sup 4}He, and {sub {Lambda}{Lambda}}{sup 4}He, are calculated in the limit of flavor-SU(3) symmetry at the physical strange quark mass with quantum chromodynamics (without electromagnetic interactions). The nuclear states are extracted from Lattice QCD calculations performed with n{sub f}=3 dynamical light quarks using an isotropic clover discretization of the quark-action in three lattice volumes of spatial extent L ~ 3.4 fm, 4.5 fm and 6.7 fm, and with a single lattice spacing b ~ 0.145 fm.
K. Bakke; H. Belich
2015-07-14
We investigate the arising of an analogue of the Landau quantization from a background of the violation of the Lorentz symmetry established by a time-like 4-vector and a field configuration of crossed electric and magnetic field. We also analyse the effects on this Landau-type system subject to a hard-wall confining potential by showing a particular case where a discrete spectrum of energy can be obtained. Further, we analyse the effects of a linear confining potential on the Landau-type system. We show that a quantum effect characterized by the dependence of the cyclotron frequency on the quantum numbers of the system can arise in this analogue of the Landau system. As an example, we calculate the cyclotron frequency associated with ground state of the system.
Nucleon-Nucleon Scattering Parameters in the Limit of SU(3) Flavor Symmetry
Beane, Silas; Chang, Emanuel; Savage, Martin; Lin, Huey-Wen; Orginos, Konstantinos; Cohen, Saul; Detmold, William; Luu, Tom; Parreno, Assumpta; Junnarkar, Parikshit; Walker-Loud, Andre Paul
2013-08-01
The scattering lengths and effective ranges that describe low-energy nucleon-nucleon scattering are calculated in the limit of SU(3)-flavor symmetry at the physical strange-quark mass with Lattice Quantum Chromodynamics. The calculations are performed with an isotropic clover discretization of the quark action in three volumes with spatial extents of L ~ 3.4 fm, 4.5 fm and 6.7 fm, and with a lattice spacing of b ~ 0.145 fm. With determinations of the energies of the two-nucleon systems ?both of which contain bound states at these light-quark masses? at rest and moving in the lattice volume, Luscher?s method is used to determine the low-energy phase shift in each channel, from which the scattering length and effective range are obtained. The scattering parameters in the {sup 1}S{sub 0} channel are found to be m{sub ?}a{sup ({sup 1}S{sub 0})} = 9.51+/-0.74+/-1.00 and m{sub ?}r{sup ({sup 1}S{sub 0})} = 4.76+/-0.37+/-0.40, and in the {sup 3}S{sub 1} channel are m{sub ?}a{sup ({sup 3}S{sub 1})} = 7.45+/-0.57+/-0.71 and m{sub ?}r{sup ({sup 3}S{sub 1})} = 3.71+/-0.28+/-0.28. These values are consistent with the two-nucleon system exhibiting Wigner?s supermultiplet symmetry, which becomes exact in the limit of large-N{sub c}.
Self-interacting scalar dark matter with local Z{sub 3} symmetry
Ko, P.; Tang, Yong E-mail: ytang@kias.re.kr
2014-05-01
We construct a self-interacting scalar dark matter (DM) model with local discrete Z{sub 3} symmetry that stabilizes a weak scale scalar dark matter X. The model assumes a hidden sector with a local U(1){sub X} dark gauge symmetry, which is broken spontaneously into Z{sub 3} subgroup by nonzero VEV of dark Higgs field ?{sub X} ((?{sub X})?0). Compared with global Z{sub 3} DM models, the local Z{sub 3} model has two new extra fields: a dark gauge field Z{sup '} and a dark Higgs field ? (a remnant of the U(1){sub X} breaking). After imposing various constraints including the upper bounds on the spin-independent direct detection cross section and thermal relic density, we find that the scalar DM with mass less than 125 GeV is allowed in the local Z{sub 3} model, in contrary to the global Z{sub 3} model. This is due to new channels in the DM pair annihilations open into Z{sup '} and ? in the local Z{sub 3} model. Most parts of the newly open DM mass region can be probed by XENON1T and other similar future experiments. Also if ? is light enough (a few MeV ?
J. Piekarewicz
2014-10-14
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.
Nash Equilibria in Discrete Routing Games with Convex Latency Functions
Mavronicolas, Marios
Nash Equilibria in Discrete Routing Games with Convex Latency Functions Martin Gairing Thomas L is determined by an arbitrary non-decreasing, non-constant and convex latency function . In a Nash equilib- rium on the link it chooses. To evaluate Nash equilibria, we formulate Social Cost as the sum of the users
Dynamic Limit Growth Indices in Discrete Time Tomasz R. Bielecki
Heller, Barbara
Dynamic Limit Growth Indices in Discrete Time Tomasz R. Bielecki 1 bielecki@iit.edu Igor Cialenco 1, Illinois Institute of Technology, Chicago, 60616 IL, USA 2 Institute of Mathematics, Jagiellonian propose a new class of mappings, called Dynamic Limit Growth Indices, that are designed to measure
DISCRETE-CONTINUUM MODELING OF METAL MATRIX COMPOSITES PLASTICITY
Devincre, Benoit
. For this reason, the pre- diction of the plastic properties of Metal Matrix Composites (MMCs) is some- times for plastic properties. On the one hand, the FE code treats the boundary value problem and cares of the conDISCRETE-CONTINUUM MODELING OF METAL MATRIX COMPOSITES PLASTICITY S. Groh1, B. Devincre1, F. Feyel2
Discrete dissipative localized modes in nonlinear magnetic metamaterials
Discrete dissipative localized modes in nonlinear magnetic metamaterials Nikolay N. Rosanov,1 effects in. References and links 1. N. Engheta and R. W. Ziolkowski, eds. Electromagnetic Metamaterials. Gorkunov, I. V. Shadrivov, and Yu. S. Kivshar, "Metamaterial tuning by manip- ulation of near
Cryptanalyzing a discrete-time chaos synchronization secure communication system
Gonzalo Alvarez; Fausto Montoya; Miguel Romera; Gerardo Pastor
2003-11-21
This paper describes the security weakness of a recently proposed secure communication method based on discrete-time chaos synchronization. We show that the security is compromised even without precise knowledge of the chaotic system used. We also make many suggestions to improve its security in future versions.
Verification in Loosely Synchronous Queue-Connected Discrete Timed Automata
Dang, Zhe
, the expressive power of timed automata has many limitations in modeling, since many real-time systems are simply. We look at a model of a queue system that consists of the following components: 1. Two discrete timed model for investigating verification problems of real-time sys- tems (see [1, 30] for surveys). However
Verification in Loosely Synchronous QueueConnected Discrete Timed Automata ?
Dang, Zhe
, the expressive power of timed automata has many limitations in modeling, since many realÂtime systems are simply. We look at a model of a queue system that consists of the following components: 1. Two discrete timed model for investigating verification problems of realÂtime sysÂ tems (see [1, 30] for surveys). However
Tensile damage response from discrete element virtual testing
Paris-Sud XI, Université de
Tensile damage response from discrete element virtual testing A. DELAPLACE LMT-Cachan, ENS Cachan conditions on brittle materials, damage can generally not be re- duced to a simple scalar. Microcrack into account the damage anisotropy in phenomenological models is a possible option, but the identification
Discrete wave turbulence of rotational capillary water waves
Adrian Constantin; Elena Kartashova; Erik Wahlén
2010-05-12
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.
Hamiltonian dynamics and constrained variational calculus: continuous and discrete settings
Manuel de Leon; Fernando Jimenez; David Martin de Diego
2012-01-01
The aim of this paper is to study the relationship between Hamiltonian dynamics and constrained variational calculus. We describe both using the notion of Lagrangian submanifolds of convenient symplectic manifolds and using the so-called Tulczyjew's triples. The results are also extended to the case of discrete dynamics and nonholonomic mechanics. Interesting applications to geometrical integration of Hamiltonian systems are obtained.
ENHANCING DISCRETE CHOICE DEMAND MODELING FOR DECISION-BASED DESIGN
Chen, Wei
the Decision-Based Design framework. Even though demand modeling techniques exist in market research, little design, in particular that facilitates engineering decision-making. In market research, two major demand1 ENHANCING DISCRETE CHOICE DEMAND MODELING FOR DECISION-BASED DESIGN In Press of ASME Journal
A DISCRETE WAVELET ANALYSIS OF FREAK WAVES IN THE OCEAN
measurement of landslide-generated impulse waves was presented in [2]. In fact, the measured results of continuous wave recordings made in the Sea of Japan during 19861990 by the Ship Research Institute of JapanA DISCRETE WAVELET ANALYSIS OF FREAK WAVES IN THE OCEAN EN-BING LIN AND PAUL C. LIU Received 25
ADAPTIVE DISCRETIZATION OF AN INTEGRO-DIFFERENTIAL EQUATION
Larsson, Stig
ADAPTIVE DISCRETIZATION OF AN INTEGRO-DIFFERENTIAL EQUATION MODELING QUASI-STATIC FRACTIONAL ORDER VISCOELASTICITY Klas Adolfsson Mikael Enelund Stig Larsson Department of Applied Mechanics, Chalmers University of Technology, SEÂ412 96 GÂ¨oteborg, Sweden, klas.adolfsson@chalmers.se Department of Applied Mechanics
Energy-Efficient Discrete Cosine Transform on Ronald Scrofano
Jang, Ju-Wook
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
Inverses of Multivariate Polynomial Matrices using Discrete Convolution
Young, R. Michael
Inverses of Multivariate Polynomial Matrices using Discrete Convolution R. Lobo Dept. of Elec Raleigh, NC 27695 Abstract-- A new method for inversion of rectangular matrices in a multivariate to multivariate polynomial system of equations is the subject of intensive research and has major applications
Integrating a discrete motion model into GMM based background subtraction
Wolf, Christian
consecutive frames minimizing a global energy function taking into account spatial and temporal re- lationships. A discrete approximative optical-flow like motion model is integrated into the energy function, for instance for track- ing algorithms. Most existing methods build an explicit background model either using
Generic Average Modeling and Simulation of Discrete Controllers
be advantageous to have the capability of running AC analysis of digitally controlled power systems on a general is suggested for the design of discrete controllers for switch mode systems. I. INTRODUCTION The current, in principle, to large signal (time domain) analysis. However, classical control design methods in power
Wave-packet continuum discretization for quantum scattering
O. A. Rubtsova; V. I. Kukulin; V. N. Pomerantsev
2015-01-15
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.
Double-distribution-function discrete Boltzmann model for combustion
Chuandong Lin; Aiguo Xu; Guangcai Zhang; Yingjun Li
2015-06-21
A 2-dimensional discrete Boltzmann model for combustion is presented. Mathematically, the model is composed of two coupled discrete Boltzmann equations for two species and a phenomenological evolution equation for chemical reaction process. Physically, the model is equivalent to a Navier-Stokes model supplemented by a coarse-grained model for the thermodynamic nonequilibrium behaviours. This model adopts $16$ discrete velocities. It works for both subsonic and supersonic combustion phenomena with flexible specific heat ratio. To discuss the physical accuracy of the coarse-grained model for nonequilibrium behaviours, three other discrete velocity models are used for comparisons. Numerical results are compared with analytical solutions based on both the first-order and second-order truncations of the distribution function. It is confirmed that the physical accuracy increases with the increasing moment relations needed by nonequlibrium manifestations. Furthermore, a criterion of transition from incomplete to complete combustion is obtained. Compared with the single distribution function model, this model can simulate incomplete combustion, decomposition and combination reactions.
Discrete dragline attachment induces aggregation in spiderlings of a solitary species
Theraulaz, Guy
Discrete dragline attachment induces aggregation in spiderlings of a solitary species RAPHAEL and the experimental data shows that the discrete pattern of silk dragline attachment is the key mechanism involved
Siu, Ho Chit
2015-01-01
We present a discrete numerical approach for forward-modeling lightcurves from stellar occultations by planetary atmospheres. Our discrete approach provides a way to arbitrarily set atmospheric properties at any radius ...
Discrete Applied Mathematics 154 (2006) 16331639 www.elsevier.com/locate/dam
Hartke, Stephen
2006-01-01
Discrete Applied Mathematics 154 (2006) 16331639 www.elsevier.com/locate/dam Note The elimination. doi:10.1016/j.dam.2005.11.009 #12;1634 Stephen G. Hartke / Discrete Applied Mathematics 154 (2006
Symmetry classification of quasi-linear PDE's containing arbitrary functions
Giampaolo Cicogna
2007-02-02
We consider the problem of performing the preliminary "symmetry classification'' of a class of quasi-linear PDE's containing one or more arbitrary functions: we provide an easy condition involving these functions in order that nontrivial Lie point symmetries be admitted, and a "geometrical'' characterization of the relevant system of equations determining these symmetries. Two detailed examples will elucidate the idea and the procedure: the first one concerns a nonlinear Laplace-type equation, the second a generalization of an equation (the Grad-Schl\\"uter-Shafranov equation) which is used in magnetohydrodynamics.
Excitation energy dependence of symmetry energy of finite nuclei
S. K. Samaddar; J. N. De; X. Vinas; M. Centelles
2007-10-11
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.
Non-relativistic conformal symmetries in fluid mechanics
P. -M. Zhang; P. A. Horvathy
2009-10-24
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.
Computer Algebra Solving of First Order ODEs Using Symmetry Methods
E. S. Cheb-Terrab; L. G. S. Duarte; L. A. C. P. da Mota
1996-07-16
A set of Maple V R.3/4 computer algebra routines for the analytical solving of 1st. order ODEs, using Lie group symmetry methods, is presented. The set of commands includes a 1st. order ODE-solver and routines for, among other things: the explicit determination of the coefficients of the infinitesimal symmetry generator; the construction of the most general invariant 1st. order ODE under given symmetries; the determination of the canonical coordinates of the underlying invariant group; and the testing of the returned results.
Gauge Symmetry and Supersymmetry of Multiple M2-Branes
Jonathan Bagger; Neil Lambert
2007-12-20
In previous work we proposed a field theory model for multiple M2-branes based on an algebra with a totally antisymmetric triple product. In this paper we gauge a symmetry that arises from the algebra's triple product. We then construct a supersymmetric theory that is consistent with all the symmetries expected of a multiple M2-brane theory: 16 supersymmetries, conformal invariance, and an SO(8) R-symmetry that acts on the eight transverse scalars. The gauge field is not dynamical. The result is a new type of maximally supersymmetric gauge theory in three dimensions.
Chiral symmetry breaking with no bilinear condensate revisited
Kanazawa, Takuya
2015-01-01
While chiral symmetry breaking in the QCD vacuum is attributed to nonzero chiral condensate, an alternative symmetry breaking pattern with no chiral condensate is also possible, as pointed out by Stern. We study the $\\theta$ dependence of this unorthodox phase on the basis of chiral perturbation theory. Physical observables such as energy density, topological susceptibility, non-local chiral order parameter and meson masses are computed analytically in the epsilon-regime. At nonzero $\\theta$ we find an exotic phase that breaks vectorial flavor symmetries in a way analogous to the Aoki phase in lattice QCD.
Influence of density dependent symmetry energy on Elliptical flow
Karan Singh Vinayak; Suneel Kumar
2011-09-18
The effect of density dependent symmetry energy on elliptical flow is studied using isospin-dependent quantum molecular dynamics model(IQMD). We have used the reduced isospin- dependent cross-section with hard(H) equation of state to study the sensitivity of elliptical flow towards symmetry energy in the energy range of 50 - 1000 MeV/nucleon. The elliptical flow becomes zero at a particular energy termed as transition energy. A systematic effort has been made to pin down the transition energy for the density dependent symmetry energy.
The role of gauge symmetry in spintronics
Sobreiro, R.F.
2011-12-15
In this work we employ a field theoretical approach to explain the nature of the non-conserved spin current in spintronics. In particular, we consider the usual U(1) gauge theory for the electromagnetism at classical level in order to obtain the broken continuity equation involving the spin current and spin-transfer torque. Inspired by the recent work of A. Vernes, B. L. Gyorffy and P. Weinberger where they obtain such an equation in terms of relativistic quantum mechanics, we formalize their result in terms of the well known currents of field theory such as the Bargmann-Wigner current and the chiral current. Thus, an interpretation of spintronics is provided in terms of Noether currents (conserved or not) and symmetries of the electromagnetism. In fact, the main result of the present work is that the non-conservation of the spin current is associated with the gauge invariance of physical observables where the breaking term is proportional to the chiral current. Moreover, we generalize their result by including the electromagnetic field as a dynamical field instead of an external one.
Time reversal symmetry and collapse models
Daniel Bedingham; Owen Maroney
2015-02-24
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.
The role of gauge symmetry in spintronics
Sobreiro, R F
2011-01-01
In this work we employ a field theoretical approach to explain the nature of the non-conserved spin current in spintronics. In particular, we consider the usual U(1) gauge theory for the electromagnetism at classical level in order to obtain the broken continuity equation involving the spin current and spin-transfer torque. Inspired in the recent work of A. Vernes, B. L. Gyorffy and P. Weinberger where they obtain such equation in terms of relativistic quantum mechanics, we formalize their result in terms of the well known currents of field theory such as the Bargmann-Wigner current and the chiral current. Thus, an interpretation of spintronics is provided in terms of Noether currents (conserved or not) and symmetries of the electromagnetism. In fact, the main result of the present work is that the non-conservation of the spin current is associated to the gauge invariance of physical observables where the breaking term is proportional to the chiral current. Moreover, we generalize their result by including th...
The role of gauge symmetry in spintronics
R. F. Sobreiro; V. J. Vasquez Otoya
2011-08-31
In this work we employ a field theoretical approach to explain the nature of the non-conserved spin current in spintronics. In particular, we consider the usual U(1) gauge theory for the electromagnetism at classical level in order to obtain the broken continuity equation involving the spin current and spin-transfer torque. Inspired in the recent work of A. Vernes, B. L. Gyorffy and P. Weinberger where they obtain such equation in terms of relativistic quantum mechanics, we formalize their result in terms of the well known currents of field theory such as the Bargmann-Wigner current and the chiral current. Thus, an interpretation of spintronics is provided in terms of Noether currents (conserved or not) and symmetries of the electromagnetism. In fact, the main result of the present work is that the non-conservation of the spin current is associated to the gauge invariance of physical observables where the breaking term is proportional to the chiral current. Moreover, we generalize their result by including the electromagnetic field as a dynamical field instead of an external one.
Dynamical Symmetries Reflected in Realistic Interactions
Sviratcheva, K.D.; Draayer, J.P.; /Louisiana State U.; Vary, J.P.; /Iowa State U. /LLNL, Livermore /SLAC
2007-04-06
Realistic nucleon-nucleon (NN) interactions, derived within the framework of meson theory or more recently in terms of chiral effective field theory, yield new possibilities for achieving a unified microscopic description of atomic nuclei. Based on spectral distribution methods, a comparison of these interactions to a most general Sp(4) dynamically symmetric interaction, which previously we found to reproduce well that part of the interaction that is responsible for shaping pairing-governed isobaric analog 0{sup +} states, can determine the extent to which this significantly simpler model Hamiltonian can be used to obtain an approximate, yet very good description of low-lying nuclear structure. And furthermore, one can apply this model in situations that would otherwise be prohibitive because of the size of the model space. In addition, we introduce a Sp(4) symmetry breaking term by including the quadrupole-quadrupole interaction in the analysis and examining the capacity of this extended model interaction to imitate realistic interactions. This provides a further step towards gaining a better understanding of the underlying foundation of realistic interactions and their ability to reproduce striking features of nuclei such as strong pairing correlations or collective rotational motion.
Leptonic mixing, family symmetries, and neutrino phenomenology
Medeiros Varzielas, I. de [Departamento de Fisica and Centro de Fisica Teorica de Particulas, Instituto Superior Tecnico, Avenida Rovisco Pais, 1049-001 Lisboa (Portugal); Fakultaet fuer Physik, Technische Universitaet Dortmund D-44221 Dortmund (Germany); Gonzalez Felipe, R. [Departamento de Fisica and Centro de Fisica Teorica de Particulas, Instituto Superior Tecnico, Avenida Rovisco Pais, 1049-001 Lisboa (Portugal); Instituto Superior de Engenharia de Lisboa, Rua Conselheiro Emidio Navarro, 1959-007 Lisboa (Portugal); Serodio, H. [Departamento de Fisica and Centro de Fisica Teorica de Particulas, Instituto Superior Tecnico, Avenida Rovisco Pais, 1049-001 Lisboa (Portugal)
2011-02-01
Tribimaximal leptonic mixing is a mass-independent mixing scheme consistent with the present solar and atmospheric neutrino data. By conveniently decomposing the effective neutrino mass matrix associated to it, we derive generic predictions in terms of the parameters governing the neutrino masses. We extend this phenomenological analysis to other mass-independent mixing schemes which are related to the tribimaximal form by a unitary transformation. We classify models that produce tribimaximal leptonic mixing through the group structure of their family symmetries in order to point out that there is often a direct connection between the group structure and the phenomenological analysis. The type of seesaw mechanism responsible for neutrino masses plays a role here, as it restricts the choices of family representations and affects the viability of leptogenesis. We also present a recipe to generalize a given tribimaximal model to an associated model with a different mass-independent mixing scheme, which preserves the connection between the group structure and phenomenology as in the original model. This procedure is explicitly illustrated by constructing toy models with the transpose tribimaximal, bimaximal, golden ratio, and hexagonal leptonic mixing patterns.
Symmetry and composition in probabilistic theories
Alexander Wilce
2015-05-04
The past decade has seen a remarkable resurgence of the old programme of finding more or less a priori axioms for the mathematical framework of quantum mechanics. The new impetus comes largely from quantum information theory; in contrast to work in the older tradition, which tended to concentrate on structural features of individual quantum systems, the newer work is marked by an emphasis on systems in interaction. Within this newer work, one can discerne two distinct approaches: one is "top-down", and attempts to capture in category-theoretic terms what is distinctive about quantum information processing. The other is "bottom up", attempting to construct non-classical models and theories by hand, as it were, and then characterizing those features that mark out quantum-like behavior. This paper blends these approaches. We present a constructive, bottom-up recipe for building probabilistic theories having strong symmetry properties, using as data any uniform enlargement of the symmetric group $S(E)$ of any set, to a larger group $G(E)$. Subject to some natural conditions, our construction leads to a monoidal category of fully symmetric test spaces, in which the monoidal product is "non-signaling".
FOURIER PAIRS OF DISCRETE SUPPORT WITH LITTLE STRUCTURE MIHAIL N. KOLOUNTZAKIS
Kolountzakis, Mihalis
FOURIER PAIRS OF DISCRETE SUPPORT WITH LITTLE STRUCTURE MIHAIL N. KOLOUNTZAKIS Abstract. We give line of discrete support, whose Fourier Transform is also a measure of discrete support, yet this Fourier pair cannot be constructed by repeatedly applying the Poisson Summation Formula finitely many
A discrete fourth-order Lidstone problem with parameters Douglas R. Anderson a,*, Feliz Minhs b
Anderson, Douglas R.
A discrete fourth-order Lidstone problem with parameters Douglas R. Anderson a,*, Feliz Minhós b Symmetric Green's function Fixed points Fourth-order Discrete Beam Lidstone Semipositone a b s t r a c discrete fourth-order Lidstone boundary value problem with dependence on two parameters are given, using
Finite-Time Stability of Discrete-Time Nonlinear Systems: Analysis and Design
Finite-Time Stability of Discrete-Time Nonlinear Systems: Analysis and Design S. Mastellone, P. Dorato, C. T. Abdallah Abstract-- Finite-time stability of nonlinear discrete-time systems is studied we propose a new analysis result for fi- nite time stability of deterministic and stochastic discrete
HIPPO_discrete_continuous_Users_Guide_20121130 1 Revision Date: November 30, 2012
Discrete Flask and GC Sample GHG, Halocarbon, and Hydrocarbon Data (R_20121129) Summary: This data set results. Each row of the data file contains the results for all of measurements of a discrete sample / laboratory made a particular discrete measurement: 1 =AWAS/U.Miami, 2 = NWAS/NOAA+CU, 3 = PantherMSD/NOAA, 4
CERNA WORKING PAPER SERIES Patent quality and value in discrete and cumulative innovation
Paris-Sud XI, Université de
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
Controllers for Discrete Event Systems via P. Madhusudan 1 and P. S. Thiagarajan 2 ?
Parthasarathy, Madhusudan
Controllers for Discrete Event Systems via Morphisms P. Madhusudan 1 and P. S. Thiagarajan 2 ? 1 the problem of synthesising controllers for discrete event systems. Traditionally this problem is tackled therein. From the controlÂtheoretic perspective, the modelling of discreteÂevent systems (DES
Averages along polynomial sequences in discrete nilpotent groups: singular Radon transforms
Ionescu, Alexandru D; Wainger, Stephen
2012-01-01
We consider a class of operators defined by taking averages along polynomial sequences in discrete nilpotent groups. In this paper we prove $L^2$ boundedness of discrete singular Radon transforms along general polynomial sequences in discrete nilpotent groups of step 2.
Stanford University
The construction of discretely conservative finite volume schemes that also globally conserve conservation law u t + x f(u) = 0 is approximated by the semi-discrete conservative scheme duj dt + 1 x fj+1 2 shown that shock waves can be fully resolved by non-dissipative discretizations of this type with a fine
New symmetry properties of pointlike scalar and Dirac particles
Alexander J. Silenko
2015-03-13
New symmetry properties are found for pointlike scalar and Dirac particles (Higgs boson and all leptons) in Riemannian and Riemann-Cartan 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 (or Riemann-Cartan) 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.
Dimensions of symmetry in syntax : agreement and clausal architecture
Hiraiwa, Ken, 1974-
2005-01-01
(cont.) are, then, determined at phase levels by late insertion of categorial features. One crucial aspect of the proposed theory of structural symmetry involves interweaving effects, which emerge as categorial determination ...
Symmetry Methods for a Geophysical Mass Flow Model
Torrisi, Mariano; Tracina, Rita
2011-09-14
In the framework of symmetry analysis, the class of 2 x 2 PDE systems to whom belong the Savage and Hutter model and the Iverson model is considered. New classes of exact solutions are found.
Fundamental Symmetry Tests Using He Dual Noble Gas Maser
Walsworth, Ronald L.
;c 2000 by David Chaiyarat Bear All rights reserved #12;Advisor: Dr. Ronald Walsworth Author: David violating parameters in a standard-model extension that allows violation of these symmetries. Our Temperature Control . . . . . . . . . . . . . . . . . . . . . 72 3.4 Optical Pumping System
Symmetry-Breaking Orbital Anisotropy Observed for Detwinned Ba...
Office of Scientific and Technical Information (OSTI)
Observed for Detwinned Ba(Fe (1-X) Co (X) ) (2) As (2) Above the Spin Density Wave Transition Citation Details In-Document Search Title: Symmetry-Breaking Orbital...