Vacuum space-times with controlled singularities and without symmetries
Piotr T. Chru?ciel; Paul Klinger
2015-07-01T23:59:59.000Z
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
1998-09-18T23:59:59.000Z
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
2009-07-02T23:59:59.000Z
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.
Space-time symmetries of noncommutative spaces
Calmet, Xavier [Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 (United States)
2005-04-15T23:59:59.000Z
We define a noncommutative Lorentz symmetry for canonical noncommutative spaces. The noncommutative vector fields and the derivatives transform under a deformed Lorentz transformation. We show that the star product is invariant under noncommutative Lorentz transformations. We then apply our idea to the case of actions obtained by expanding the star product and the fields taken in the enveloping algebra via the Seiberg-Witten maps and verify that these actions are invariant under these new noncommutative Lorentz transformations. We finally consider general coordinate transformations and show that the metric is undeformed.
Physics in discrete spaces (A): Space-Time organization
P. Peretto
2010-12-29T23:59:59.000Z
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.
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
2014-11-29T23:59:59.000Z
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
2015-06-28T23:59:59.000Z
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
2010-09-26T23:59:59.000Z
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.
Error bounds for space-time discretizations of a 3D model for shape-memory materials
Stefanelli, Ulisse
Error bounds for space-time discretizations of a 3D model for shape-memory materials Alexander in shape- memory materials. After recalling existence and uniqueness results, a fully evolution of shape-memory alloys (SMAs). The latter are metallic alloys showing some surprising thermo
Neutrino Mixing and Discrete Symmetries
Hu, Bo
2012-01-01T23:59:59.000Z
A model independent study of neutrino mixing based on a new method to derive mixing patterns is presented. An interesting result we find is that, in the case where unbroken residual symmetries of the Majorana neutrino and left-handed charged-lepton mass matrices obey some general assumptions, the complete set of possible mixing patterns can be determined by the solutions to the constraint equation with the help of algebraic number theory. This method can also be applied to more general cases beyond the minimal scenario. Several applications and phenomenological implications are discussed.
Quantization of Point Particles in 2+1 Dimensional Gravity and Space-Time Discreteness
G. 't Hooft
1996-01-10T23:59:59.000Z
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
Discrete Symmetry and Stability in Hamiltonian Dynamics
Tassos Bountis; George Chechin; Vladimir Sakhnenko
2010-05-31T23:59:59.000Z
In this tutorial we address the existence and stability of periodic and quasiperiodic orbits in N degree of freedom Hamiltonian systems and their connection with discrete symmetries. Of primary importance in our study are the nonlinear normal modes (NNMs), i.e periodic solutions which represent continuations of the system's linear normal modes in the nonlinear regime. We examine the existence of such solutions and discuss different methods for constructing them and studying their stability under fixed and periodic boundary conditions. In the periodic case, we employ group theoretical concepts to identify a special type of NNMs called one-dimensional "bushes". We describe how to use linear combinations such NNMs to construct s(>1)-dimensional bushes of quasiperiodic orbits, for a wide variety of Hamiltonian systems and exploit the symmetries of the linearized equations to simplify the study of their destabilization. Applying this theory to the Fermi Pasta Ulam (FPU) chain, we review a number of interesting results, which have appeared in the recent literature. We then turn to an analytical and numerical construction of quasiperiodic orbits, which does not depend on the symmetries or boundary conditions. We demonstrate that the well-known "paradox" of FPU recurrences may be explained in terms of the exponential localization of the energies Eq of NNM's excited at the low part of the frequency spectrum, i.e. q=1,2,3,.... Thus, we show that the stability of these low-dimensional manifolds called q-tori is related to the persistence or FPU recurrences at low energies. Finally, we discuss a novel approach to the stability of orbits of conservative systems, the GALIk, k=2,...,2N, by means of which one can determine accurately and efficiently the destabilization of q-tori, leading to the breakdown of recurrences and the equipartition of energy, at high values of the total energy E.
Leptonic Dirac CP Violation Predictions from Residual Discrete Symmetries
Girardi, I; Stuart, Alexander J; Titov, A V
2015-01-01T23:59:59.000Z
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
2015-09-08T23:59:59.000Z
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))
1994-12-01T23:59:59.000Z
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.
Semiclassical approach to discrete symmetries in quantum chaos
Joyner, Chris; Sieber, Martin
2012-01-01T23:59:59.000Z
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
2012-02-22T23:59:59.000Z
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
2015-05-29T23:59:59.000Z
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.
Non-Abelian discrete gauge symmetries in F-theory
Grimm, Thomas W; Regalado, Diego
2015-01-01T23:59:59.000Z
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
2015-04-23T23:59:59.000Z
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.
Discrete Symmetries (C,P,T) in Noncommutative Field Theories
M. M. Sheikh-Jabbari
2000-04-29T23:59:59.000Z
In this paper we study the invariance of the noncmmutative gauge theories under C, P and T transformations. For the noncommutative space (when only the spatial part of $\\theta$ is non-zero) we show that NCQED is Parity invariant. In addition, we show that under charge conjugation the theory on noncommutative $R^4_{\\theta}$ is transformed to the theory on $R^4_{-\\theta}$, so NCQED is a CP violating theory. The theory remains invariant under time reversal if, together with proper changes in fields, we also change $\\theta$ by $-\\theta$. Hence altogether NCQED is CPT invariant. Moreover we show that the CPT invariance holds for general noncommutative space-time.
Lepton Mixing Predictions from (Generalised) CP and Discrete Flavour Symmetry
Thomas Neder
2015-03-31T23:59:59.000Z
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
2005-01-01T23:59:59.000Z
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
2005-02-09T23:59:59.000Z
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.
Korzy?ski, Miko?aj; Bentivegna, Eloisa
2015-01-01T23:59:59.000Z
We discuss the possibility of a dimensional reduction of the Einstein equations in S3 black-hole lattices. It was reported in previous literature that the evolution of spaces containing curves of local, discrete rotational and reflection Symmetry (LDRRS) can be carried out via a system of ODEs along these curves. However, 3+1 Numerical Relativity computations demonstrate that this is not the case, and we show analytically that this is due to the presence of a tensorial quantity which is not suppressed by the symmetry. We calculate the term analytically, and verify numerically for an 8-black-hole lattice that it fully accounts for the anomalous results, and thus quantify its magnitude in this specific case. The presence of this term prevents the exact evolution of these spaces via previously-reported methods which do not involve a full 3+1 integration of Einstein's equation.
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
2011-08-19T23:59:59.000Z
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.
Daiqin Su; T. C. Ralph
2015-07-02T23:59:59.000Z
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.
Metastring Theory and Modular Space-time
Laurent Freidel; Robert G. Leigh; Djordje Minic
2015-02-27T23:59:59.000Z
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
2008-09-24T23:59:59.000Z
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
2012-01-01T23:59:59.000Z
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.
Haesen, S; Haesen, Stefan; Verstraelen, Leopold
2004-01-01T23:59:59.000Z
Due to the growing interest in embeddings of space-time in higher-dimensional spaces we consider a specific type of embedding. After proving an inequality between intrinsically defined curvature invariants and the squared mean curvature, we extend the notion of ideal embeddings from Riemannian geometry to the indefinite case. Ideal embeddings are such that the embedded manifold receives the least amount of tension from the surrounding space. Then it is shown that the de Sitter spaces, a Robertson-Walker space-time and some anisotropic perfect fluid metrics can be ideally embedded in a five-dimensional pseudo-Euclidean space.
Stefan Haesen; Leopold Verstraelen
2004-04-01T23:59:59.000Z
Due to the growing interest in embeddings of space-time in higher-dimensional spaces we consider a specific type of embedding. After proving an inequality between intrinsically defined curvature invariants and the squared mean curvature, we extend the notion of ideal embeddings from Riemannian geometry to the indefinite case. Ideal embeddings are such that the embedded manifold receives the least amount of tension from the surrounding space. Then it is shown that the de Sitter spaces, a Robertson-Walker space-time and some anisotropic perfect fluid metrics can be ideally embedded in a five-dimensional pseudo-Euclidean space.
Space-Time Galerkin Projection of Electro-Magnetic Fields
Wang, Zifu; Hofmann, Heath
2015-01-01T23:59:59.000Z
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.
Discrete canonical analysis of three dimensional gravity with cosmological constant
J. Berra-Montiel; J. E. Rosales-Quintero
2014-06-03T23:59:59.000Z
We discuss the interplay between standard canonical analysis and canonical discretization in three-dimensional gravity with cosmological constant. By using the Hamiltonian analysis, we find that the continuum local symmetries of the theory are given by the on-shell space-time diffeomorphisms, which at the action level, corresponds to the Kalb-Ramond transformations. At the time of discretization, although this symmetry is explicitly broken, we prove that the theory still preserves certain gauge freedom generated by a constant curvature relation in terms of holonomies and the Gauss's law in the lattice approach.
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 a theoretical analysis of computation by physical systems. We focus on the role of simple examples in space, time, mass and energy can compute all possible functions on discrete data. The system is a form
Space-time Curvature of Classical Electromagnetism
R. W. M. Woodside
2004-10-08T23:59:59.000Z
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.
Quantum Field Theory on Noncommutative Space-Times and the Persistence of Ultraviolet Divergences
M. Chaichian; A. Demichev; P. Presnajder
1999-04-13T23:59:59.000Z
We study properties of a scalar quantum field theory on two-dimensional noncommutative space-times. Contrary to the common belief that noncommutativity of space-time would be a key to remove the ultraviolet divergences, we show that field theories on a noncommutative plane with the most natural Heisenberg-like commutation relations among coordinates or even on a noncommutative quantum plane with $E_q(2)$-symmetry have ultraviolet divergences, while the theory on a noncommutative cylinder is ultraviolet finite. Thus, ultraviolet behaviour of a field theory on noncommutative spaces is sensitive to the topology of the space-time, namely to its compactness. We present general arguments for the case of higher space-time dimensions and as well discuss the symmetry transformations of physical states on noncommutative space-times.
Ning Wu
2012-07-11T23:59:59.000Z
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
2014-12-11T23:59:59.000Z
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 ...
2014-10-31T23:59:59.000Z
Oct 31, 2014 ... This is analogous to a gradient flow in a highly wiggling or oscillatory energy landscape. .... where the Sh(·) is the solution operator of (6), i.e. w(t) = Sh(t)[uk]. Note that the ...... The strategy of proof follows [2] closely. Essentially ...
Brodsky, S J; Hwang, D S
2006-01-01T23:59:59.000Z
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 ...
Brodsky, Stanley J.; /SLAC; Gardner, Susan; /Kentucky U.; Hwang, Dae Sung; /Sejong U.
2006-01-11T23:59:59.000Z
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)
2006-02-01T23:59:59.000Z
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}.
Space-time defects and teleparallelism
J. W. Maluf; A. Goya
2001-10-24T23:59:59.000Z
We consider the class of space-time defects investigated by Puntigam and Soleng. These defects describe space-time dislocations and disclinations (cosmic strings), and are in close correspondence to the actual defects that arise in crystals and metals. It is known that in such materials dislocations and disclinations require a small and large amount of energy, respectively, to be created. The present analysis is carried out in the context of the teleparallel equivalent of general relativity (TEGR). We evaluate the gravitational energy of these space-time defects in the framework of the TEGR and find that there is an analogy between defects in space-time and in continuum material systems: the total gravitational energy of space-time dislocations and disclinations (considered as idealized defects) is zero and infinit, respectively.
Space-time singularities and the axion in the Poincare coset models ISO(2,1)/H
Roberto Casadio; Benjamin Harms
1996-06-12T23:59:59.000Z
By promoting an invariant subgroup $H$ of $ISO(2,1)$ to a gauge symmetry of a WZWN action, we obtain the description of a bosonic string moving either in a curved 4-dimensional space--time with an axion field and curvature singularities or in 3-dimensional Minkowski space--time.
Relativity of Space-Time Geometry
L. V. Verozub
1996-06-14T23:59:59.000Z
We argue that space-time geometry is not absolute with respect to the frame of reference being used. The space-time metric differential form $ds$ in noninertial frames of reference (NIFR) is caused by the properties of the used frames in accordance with the Berkley - Leibnitz - Mach - Poincar\\'{e} ideas about relativity of space and time . It is shown that the Sagnac effect and the existence of inertial forces in NIFR can be considered from this point of view. An experimental test is proposed.
On time-reversal and space-time harmonic processes for Markovian quantum channels
Francesco Ticozzi; Michele Pavon
2009-04-29T23:59:59.000Z
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.
Veeravalli, Venugopal
Demodulation Outer Decoder Y = Nt HX + Z Space-Time Coding: Signal Processing Toolbox Rate vs. Reliability vs Code: An example MISO 2x1 Channel: y = 2 [h1 h2]X + z Channel Capacity: I(X; y|H) = log(1 + 2 ||H||2): Beamforming Example of use of finite rate feedback: MISO 4 x 1 No Feedback: Full diversity with = 3 4 Antenna
Modern space-time and undecidability
Rodolfo Gambini; Jorge Pullin
2008-01-16T23:59:59.000Z
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.
Y. M. Cho
2007-03-02T23:59:59.000Z
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.
Alexander N. Jourjine
2010-03-12T23:59:59.000Z
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.
Quantum Space-Time and Noncommutative Gauge Field Theories
Sami Saxell
2009-09-17T23:59:59.000Z
The three original publications in this thesis encompass various aspects in the still developing area of noncommutative quantum field theory, ranging from fundamental concepts to model building. One of the key features of noncommutative space-time is the apparent loss of Lorentz invariance that has been addressed in different ways in the literature. One recently developed approach is to eliminate the Lorentz violating effects by integrating over the parameter of noncommutativity. Fundamental properties of such theories are investigated in this thesis. Another issue addressed is model building, which is difficult in the noncommutative setting due to severe restrictions on the possible gauge symmetries imposed by the noncommutativity of the space-time. Possible ways to relieve these restrictions are investigated and applied and a noncommutative version of the Minimal Supersymmetric Standard Model is presented. While putting the results obtained in the three original publications into their proper context, the introductory part of this thesis aims to provide an overview of the present situation in the field.
Fermion Fields in BTZ Black Hole Space-Time and Entanglement Entropy
Dharm Veer Singh; Sanjay Siwach
2015-08-07T23:59:59.000Z
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.
Holographic Space-time and Newton's Law
Tom Banks; Willy Fischler
2013-10-25T23:59:59.000Z
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.
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 DeliciousPlasmaP a g eWorks -09-0018-CXNuonYucheng Xinyuan HeatSolkar SolarSouthSolarColorado)Sowitech JumpSpace-Time
R. L. Oldershaw
2007-12-19T23:59:59.000Z
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
1991-10-02T23:59:59.000Z
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.
Space-Time as an Orderparameter Manifold in Random Networks and the Emergence of Physical Points
Manfred Requardt
1999-02-11T23:59:59.000Z
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
1999-12-15T23:59:59.000Z
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
Wick rotation for quantum field theories on degenerate Moyal space(-time)
Grosse, Harald; Lechner, Gandalf [Department of Physics, University of Vienna, 1090 Vienna (Austria)] [Department of Physics, University of Vienna, 1090 Vienna (Austria); Ludwig, Thomas [Max-Planck-Institute for Mathematics in the Sciences, 04103 Leipzig (Germany) [Max-Planck-Institute for Mathematics in the Sciences, 04103 Leipzig (Germany); Institute for Theoretical Physics, University of Leipzig, 04009 Leipzig (Germany); Verch, Rainer [Institute for Theoretical Physics, University of Leipzig, 04009 Leipzig (Germany)] [Institute for Theoretical Physics, University of Leipzig, 04009 Leipzig (Germany)
2013-02-15T23:59:59.000Z
In this paper the connection between quantum field theories on flat noncommutative space(-times) in Euclidean and Lorentzian signature is studied for the case that time is still commutative. By making use of the algebraic framework of quantum field theory and an analytic continuation of the symmetry groups which are compatible with the structure of Moyal space, a general correspondence between field theories on Euclidean space satisfying a time zero condition and quantum field theories on Moyal Minkowski space is presented ('Wick rotation'). It is then shown that field theories transferred to Moyal space(-time) by Rieffel deformation and warped convolution fit into this framework, and that the processes of Wick rotation and deformation commute.
Yue-Liang Wu
2007-01-22T23:59:59.000Z
Based on a maximally symmetric minimal unification hypothesis and a quantum charge-dimension correspondence principle, it is demonstrated that each family of quarks and leptons belongs to the Majorana-Weyl spinor representation of 14-dimensions that relate to quantum spin-isospin-color charges. Families of quarks and leptons attribute to a spinor structure of extra 6-dimensions that relate to quantum family charges. Of particular, it is shown that 10-dimensions relating to quantum spin-family charges form a motional 10-dimensional quantum space-time with a generalized Lorentz symmetry SO(1,9), and 10-dimensions relating to quantum isospin-color charges become a motionless 10-dimensional quantum intrinsic space. Its corresponding 32-component fermions in the spinor representation possess a maximal gauge symmetry SO(32). As a consequence, a maximally symmetric minimal unification model SO(32) containing three families in ten dimensional quantum space-time is naturally obtained by choosing a suitable Majorana-Weyl spinor structure into which quarks and leptons are directly embedded. Both resulting symmetry and dimensions coincide with the ones of type I string and heterotic string SO(32) in string theory.
Space-Time Noncommutative Field Theories And Unitarity
Jaume Gomis; Thomas Mehen
2000-08-01T23:59:59.000Z
We study the perturbative unitarity of noncommutative scalar field theories. Field theories with space-time noncommutativity do not have a unitary S-matrix. Field theories with only space noncommutativity are perturbatively unitary. This can be understood from string theory, since space noncommutative field theories describe a low energy limit of string theory in a background magnetic field. On the other hand, there is no regime in which space-time noncommutative field theory is an appropriate description of string theory. Whenever space-time noncommutative field theory becomes relevant massive open string states cannot be neglected.
Spinorial space-time and Friedmann-like equations (I)
to the space-time structure felt locally by standard matter at low energy [3]. At the stage considered here.gonzalez-mestres@megatrend.edu.rs at the Cosmology Laboratory, Megatrend University, Belgrade (Serbia) and Paris (France) ; Luis
New orthogonal space-time block codes with full diversity
Dalton, Lori Anne
2002-01-01T23:59:59.000Z
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 ...
Horizons in Robinson-Trautman space-times
W. Natorf; J. Tafel
2008-07-18T23:59:59.000Z
The past quasi-local horizons in vacuum Robinson-Trautman spacetimes are described. The case of a null (non-expanding) horizon is discussed. It is shown that the only Robinson-Trautman space-time admitting such a horizon with sections diffeomorphic to S_2 is the Schwarzschild space-time. Weakening this condition leads to the horizons of the C-metric. Properties of the hypersurface r=2m for finite retarded time u are examined.
Wu, Yue-Liang
2015-01-01T23:59:59.000Z
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...
False vacuum decay in de Sitter space-time
V. A. Rubakov; S. M. Sibiryakov
1999-05-25T23:59:59.000Z
We suggest a technique that explicitly accounts for the structure of an initial state of quantum field in the semiclassical calculations of path integral in curved space-time, and consider decay of metastable state (conformal vacuum of scalar particles above false classical vacuum) in background de Sitter space-time as an example. Making use of this technique, we justify the Coleman-De Luccia approach to the calculation of the decay probability. We propose an interpretation of the Hawking-Moss instanton as a limiting case of constrained instantons. We find that an inverse process of the transition from true vacuum to false one is allowed in de Sitter space-time, and calculate the corresponding probability.
Tureanu, Anca [High Energy Physics Division, Department of Physical Sciences, University of Helsinki and Helsinki Institute of Physics, P.O. Box 64, FIN-00014 Helsinki (Finland)
2006-09-15T23:59:59.000Z
In the framework of quantum field theory on noncommutative space-time with the symmetry group O(1,1)xSO(2), we prove that the Jost-Lehmann-Dyson representation, based on the causality condition taken in connection with this symmetry, leads to the mere impossibility of drawing any conclusion on the analyticity of the 2{yields}2-scattering amplitude in cos {theta}, {theta} being the scattering angle. Discussions on the possible ways of obtaining high-energy bounds analogous to the Froissart-Martin bound on the total cross section are also presented.
Space-time inhomogeneity, anisotropy and gravitational collapse
R. Sharma; R. Tikekar
2012-06-24T23:59:59.000Z
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.
Tensor distributions on signature-changing space-times
David Hartley; Robin W. Tucker; Philip A. Tuckey; Tevian Dray
1997-01-21T23:59:59.000Z
Irregularities in the metric tensor of a signature-changing space-time suggest that field equations on such space-times might be regarded as distributional. We review the formalism of tensor distributions on differentiable manifolds, and examine to what extent rigorous meaning can be given to field equations in the presence of signature-change, in particular those involving covariant derivatives. We find that, for both continuous and discontinuous signature-change, covariant differentiation can be defined on a class of tensor distributions wide enough to be physically interesting.
Electromagnetic space-time crystals. II. Fractal computational approach
G. N. Borzdov
2014-10-20T23:59:59.000Z
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.
Non-commutative Einstein-Proca Space-time
Blanca Gónzales; Román Linares; Marco Maceda; Oscar Sánchez-Santos
2014-09-12T23:59:59.000Z
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.
Path integral for space-time noncommutative field theory
Fujikawa, Kazuo [Institute of Quantum Science, College of Science and Technology, Nihon University, Chiyoda-ku, Tokyo 101-8308 (Japan)
2004-10-15T23:59:59.000Z
The path integral for space-time noncommutative theory is formulated by means of Schwinger's action principle, which is based on the equations of motion and a suitable ansatz of asymptotic conditions. The resulting path integral has essentially the same physical basis as the Yang-Feldman formulation. It is first shown that higher derivative theories are neatly dealt with by the path integral formulation, and the underlying canonical structure is recovered by the Bjorken-Johnson-Low (BJL) prescription from correlation functions defined by the path integral. A simple theory which is nonlocal in time is then analyzed for an illustration of the complications related to quantization, unitarity, and positive energy conditions. From the viewpoint of the BJL prescription, the naive quantization in the interaction picture is justified for space-time noncommutative theory but not for the simple theory nonlocal in time. We finally show that the perturbative unitarity and the positive energy condition, in the sense that only the positive energy flows in the positive time direction for any fixed time slice in space-time, are not simultaneously satisfied for space-time noncommutative theory by the known methods of quantization.
Zen and the Art of Space-Time Manufacturing
Orfeu Bertolami
2013-03-10T23:59:59.000Z
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.
Energy Distribution of a Gödel-Type Space-Time
Ragab M. Gad
2004-01-29T23:59:59.000Z
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
1997-07-14T23:59:59.000Z
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^{\
New orthogonal space-time block codes with full diversity
Dalton, Lori Anne
2002-01-01T23:59:59.000Z
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...
Neutrino flavor oscillations in a curved space-time
Luca Visinelli
2015-05-06T23:59:59.000Z
Using a WKB approximation of the Dirac equation in a curved spacetime, we obtain the expression for the phase shift between two neutrino mass eigenstates in a generic gravitational field. We apply this expression to two specific space-time geometries, namely the Kerr-Newman metric describing a rotating and charged black hole, and the Friedmann-Robertson-Walker metric.
Space time coded code division multiplexing on SC140 DSP
Menon, Murali P
2001-01-01T23:59:59.000Z
The aim of this research is to design a high data rate wireless communication system for multi-path fading channels. Code-division multiplexing is proposed as a modulation scheme for a space-time coded multiple antenna system that would guarantee...
An extended Dirac equation in noncommutative space-time
R. Vilela Mendes
2015-02-01T23:59:59.000Z
Stabilizing, by deformation, the algebra of relativistic quantum mechanics a non-commutative space-time geometry is obtained. The exterior algebra of this geometry leads to an extended massless Dirac equation which has both a massless and a large mass solution. The nature of the solutions is discussed, as well as the effects of coupling the two solutions.
An extended Dirac equation in noncommutative space-time
Mendes, R Vilela
2015-01-01T23:59:59.000Z
Stabilizing, by deformation, the algebra of relativistic quantum mechanics a non-commutative space-time geometry is obtained. The exterior algebra of this geometry leads to an extended massless Dirac equation which has both a massless and a large mass solution. The nature of the solutions is discussed, as well as the effects of coupling the two solutions.
Entanglement in a multiverse with no common space-time
S. J. Robles-Pérez
2012-12-19T23:59:59.000Z
Inter-universal entanglement may even exist in a multiverse in which there is no common space-time among the universes. In particular, the entanglement between the expanding and contracting branches of the universe might have observable consequences in the dynamical and thermodynamical properties of one single branch, making therefore testable the whole multiverse proposal, at least in principle.
Entanglement in a multiverse with no common space-time
Robles-Pérez, S J
2012-01-01T23:59:59.000Z
Inter-universal entanglement may even exist in a multiverse in which there is no common space-time among the universes. In particular, the entanglement between the expanding and contracting branches of the universe might have observable consequences in the dynamical and thermodynamical properties of one single branch, making therefore testable the whole multiverse proposal, at least in principle.
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
Propagation of Test Particles and Scalar Fields on a Class of Wormhole Space-Times
Peter Taylor
2014-08-18T23:59:59.000Z
In this paper, we consider the problem of test particles and test scalar fields propagating on the background of a class of wormhole space-times. For test particles, we solve for arbitrary causal geodesics in terms of integrals which are solved numerically. These integrals are parametrized by the radius and shape of the wormhole throat as well as the initial conditions of the geodesic trajectory. In terms of these parameters, we compute the conditions for the geodesic to traverse the wormhole, to be reflected by the wormhole's potential or to be captured on an unstable bound orbit at the wormhole's throat. These causal geodesics are visualized by embedding plots in Euclidean space in cylindrical coordinates. For test scalar fields, we compute transmission coefficients and quasi-normal modes for arbitrary coupling of the field to the background geometry in the WKB approximation. We show that there always exists an unstable mode whenever the coupling constant is greater than 1/2. This analysis is interesting since recent computations of self-interactions of a static scalar field in wormhole space-times reveal some anomalous dependence on the coupling constant, principally, the existence of an infinite discrete set of poles. We show that this pathological behavior of the self-field is an artifact of computing the interaction for values of the coupling constant that do not lie in the domain of stability.
The Xi-transform for conformally flat space-time
George Sparling
2006-12-01T23:59:59.000Z
The Xi-transform is a new spinor transform arising naturally in Einstein's general relativity. Here the example of conformally flat space-time is discussed in detail. In particular it is shown that for this case, the transform coincides with two other naturally defined transforms: one a two-variable transform on the Lie group SU(2, C), the other a transform on the space of null split octaves. The key properties of the transform are developed.
Local-time effect on small space-time scale
V. A. Panchelyuga; V. A. Kolombet; M. S. Panchelyuga; S. E. Shnoll
2006-10-18T23:59:59.000Z
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
2015-01-01T23:59:59.000Z
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.
Class of Einstein-Maxwell-dilaton-axion space-times
Matos, Tonatiuh; Miranda, Galaxia; Sanchez-Sanchez, Ruben; Wiederhold, Petra [Departamento de Fisica, Centro de Investigacion y de Estudios Avanzados del IPN, Apartado Postal 14-740, 07000 Distrito Federal (Mexico); Departamento de Fisica, Escuela Superior de Fisica y Matematicas del IPN, Edificio 9, 07738 Distrito Federal (Mexico); Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada del IPN, Legaria 694, 11500 Distrito Federal (Mexico); Departamento de Control Automatico, Centro de Investigacion y de Estudios Avanzados del IPN, Apartado Postal 14-740, 07000 Distrito Federal (Mexico)
2009-06-15T23:59:59.000Z
We use the harmonic maps ansatz to find exact solutions of the Einstein-Maxwell-dilaton-axion (EMDA) equations. The solutions are harmonic maps invariant to the symplectic real group in four dimensions Sp(4,R){approx}O(5). We find solutions of the EMDA field equations for the one- and two-dimensional subspaces of the symplectic group. Specially, for illustration of the method, we find space-times that generalize the Schwarzschild solution with dilaton, axion, and electromagnetic fields.
Class of Einstein-Maxwell-Dilaton-Axion Space-Times
Tonatiuh Matos; Galaxia Miranda; Ruben Sanchez-Sanchez; Petra Wiederhold
2009-05-26T23:59:59.000Z
We use the harmonic maps ansatz to find exact solutions of the Einstein-Maxwell-Dilaton-Axion (EMDA) equations. The solutions are harmonic maps invariant to the symplectic real group in four dimensions $Sp(4,\\Rreal)\\sim O(5)$. We find solutions of the EMDA field equations for the one and two dimensional subspaces of the symplectic group. Specially, for illustration of the method, we find space-times that generalise the Schwarzschild solution with dilaton, axion and electromagnetic fields.
The wave equation on static singular space-times
Eberhard Mayerhofer
2008-02-12T23:59:59.000Z
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
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)
2014-03-01T23:59:59.000Z
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.
Space-time noncommutative theories at finite temperature
Strelchenko, A. V.; Vassilevich, D. V. [Dnepropetrovsk National University, 49050 Dnepropetrovsk (Ukraine); Instituto de Fisica, Universidade de Sao Paulo Caixa Postal 66318 CEP 05315-970, Sao Paulo S.P. (Brazil)
2007-09-15T23:59:59.000Z
We analyze renormalization and the high-temperature expansion of the one-loop effective action of the space-time noncommutative {phi}{sup 4} theory by using the zeta-function regularization in the imaginary-time formalism (i.e., on S{sup 1}xR{sup 3}). Interestingly enough, there are no mixed (nonplanar) contributions to the counterterms as well as to the power-law high-temperature asymptotics. We also study the Wick rotation and formulate assumptions under which the real and imaginary-time formalisms are equivalent.
A Superstring Theory in Four Curved Space-Time Dimensions
I. Bars; K. Sfetsos
1991-11-20T23:59:59.000Z
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.
Photon Green Functions in Curved Space-Time
Giuseppe Bimonte; Enrico Calloni; Luciano Di Fiore; Giampiero Esposito; Leopoldo Milano; Luigi Rosa
2005-11-23T23:59:59.000Z
Quantization of electrodynamics in curved space-time in the Lorenz gauge and with arbitrary gauge parameter makes it necessary to study Green functions of non-minimal operators with variable coefficients. Starting from the integral representation of photon Green functions, we link them to the evaluation of integrals involving Gamma-functions. Eventually, the full asymptotic expansion of the Feynman photon Green function at small values of the world function, as well as its explicit dependence on the gauge parameter, are obtained without adding by hand a mass term to the Faddeev-Popov Lagrangian. Coincidence limits of second covariant derivatives of the associated Hadamard function are also evaluated, as a first step towards the energy-momentum tensor in the non-minimal case.
Effects of quantum space time foam in the neutrino sector
H. V. Klapdor-Kleingrothaus; H. Päs; U. Sarkar
2000-07-05T23:59:59.000Z
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.
Classical Duality Symmetries in Two Dimensions
John H. Schwarz
1995-05-26T23:59:59.000Z
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.
LINEAR SPACE-TIME PRECODING FOR RICIAN FADING MISO CHANNELS Mai Vu, Arogyaswami Paulraj
Vu, Mai
LINEAR SPACE-TIME PRECODING FOR RICIAN FADING MISO CHANNELS Mai Vu, Arogyaswami Paulraj Stanford, Australia Email: r.evans@ee.mu.oz.au ABSTRACT We study a space-time precoding technique for MISO wire- less in practice. In this paper, we study a particular space-time coding scheme with memory for Rician MISO
A SpaceTime Finite Element Method for the Exterior Structural Acoustics Problem
Thompson, Lonny L.
A SpaceTime Finite Element Method for the Exterior Structural Acoustics Problem: Timediscontinuous Galerkin spacetime finite element method is formu lated for the exterior structural acoustics problem Introduction A spacetime finite element formulation is presented for solution of the exterior struc tural
A Space-Time Finite Element Method for the Exterior Acoustics Problem
Thompson, Lonny L.
A Space-Time Finite Element Method for the Exterior Acoustics Problem Lonny L. Thompson Department in exterior domains is discussed. The space-time formulation for the exterior acoustics problem is obtained, the development of a space-time finite element method for so- lution of the transient acoustics problem
A SpaceTime Finite Element Method for the Exterior Acoustics Problem
Thompson, Lonny L.
A SpaceTime Finite Element Method for the Exterior Acoustics Problem by Lonny L. Thompson problem in exterior domains is discussed. The spacetime formulation for the exterior acoustics problem acoustics problem. i #12; Contents 1 Introduction 1 2 The Exterior Acoustics Problem 3 3 Spacetime finite
L. R. G. Fontes; C. M. Newman; K. Ravishankar; E. Schertzer
2007-04-20T23:59:59.000Z
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.
Eigenfunction Expansion of the Space-Time Dependent Neutron Survival
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:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports to3,1,50022,3,,0,,6,1,SeparationConnect Journal Article: Discrete phase space based(JournalApplication to a Collision
Eigenfunction Expansion of the Space-Time Dependent Neutron Survival
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:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports to3,1,50022,3,,0,,6,1,SeparationConnect Journal Article: Discrete phase space based(JournalApplication to a CollisionProbability.
Space-time complexity in solid state models
Bishop, A.R.
1985-01-01T23:59:59.000Z
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.
Majorana-Oppenheimer approach to Maxwell electrodynamics in Riemannian space-time
A. Bogush; V. Red'kov; N. Tokarevskaya; G. Spix
2009-05-03T23:59:59.000Z
The Riemann -- Silberstein -- Majorana -- Oppengeimer approach to the Maxwell electrodynamics in presence of electrical sources and arbitrary media is investigated within the matrix formalism. The symmetry of the matrix Maxwell equation under transformations of the complex rotation group SO(3.C) is demonstrated explicitly. In vacuum case, the matrix form includes four real $4 \\times 4$ matrices $\\alpha^{b}$. In presence of media matrix form requires two sets of $4 \\times 4$ matrices, $\\alpha^{b}$ and $\\beta^{b}$ -- simple and symmetrical realization of which is given. Relation of $\\alpha^{b}$ and $\\beta^{b}$ to the Dirac matrices in spinor basis is found. Minkowski constitutive relations in case of any linear media are given in a short algebraic form based on the use of complex 3-vector fields and complex orthogonal rotations from SO(3.C) group. The matrix complex formulation in the Esposito's form, based on the use of two electromagnetic 4-vector, is studied and discussed. Extension of the 3-vector complex matrix formalism to arbitrary Riemannian space-time in accordance with tetrad method by Tetrode-Weyl-Fock-Ivanenko is performed.
Hirsch, M.; Morisi, S.; Peinado, E.; Valle, J. W. F. [AHEP Group, Institut de Fisica Corpuscular--C.S.I.C./Universitat de Valencia, Edificio Institutos de Paterna, Apartado 22085, E-46071 Valencia (Spain)
2010-12-01T23:59:59.000Z
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.
Space-time BIE methods for non homogeneous exterior wave equation problems. The Dirichlet case.
Ceragioli, Francesca
Space-time BIE methods for non homogeneous exterior wave equation problems. The Dirichlet case. S. Falletta , G. Monegato , L. ScuderiÂ§ Abstract In this paper we consider the (2D and 3D) exterior problem; non homogeneous conditions; space-time boundary integral equations; numerical methods This work
Evidence for Non-perturbative String Symmetries
John H. Schwarz
1994-11-29T23:59:59.000Z
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
2015-06-22T23:59:59.000Z
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.
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)
2014-04-15T23:59:59.000Z
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 Block Coding for Frequency-Selective and Time-Varying Channels
Langendoen, Koen
such as channel capacity and reliability [2]. Space-time block coding (STBC) [3], [4] has been introduced for a multiple-input single-output (MISO) system with 2 transmit antennas and 1 receive antenna
Quantum estimation of the Schwarzschild space-time parameters of the Earth
David Edward Bruschi; Animesh Datta; Rupert Ursin; Timothy C. Ralph; Ivette Fuentes
2014-08-31T23:59:59.000Z
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.
An analysis of Texas rainfall data and asymptotic properties of space-time covariance estimators
Li, Bo
2009-06-02T23:59:59.000Z
This dissertation includes two parts. Part 1 develops a geostatistical method to calibrate Texas NexRad rainfall estimates using rain gauge measurements. Part 2 explores the asymptotic joint distribution of sample space-time covariance estimators...
Space-Time Coding for the EDGE Mobile Radio System Marceau Coupechoux
Coupechoux, Marceau
28 Space-Time Coding for the EDGE Mobile Radio System Marceau Coupechoux Alcatel CorporateResearchCenter Route de Nozay, 91460 Marcoussis. France Phone: +33- 169-63-4359, e-mail: marceau
Spectra of disc operator for twisted acceleration-enlarged Newton-Hooke space-times
Marcin Daszkiewicz
2011-01-10T23:59:59.000Z
The time-dependent spectra of disc area operator for twisted acceleration-enlarged Newton-Hooke space-times are derived. It is demonstrated that the corresponding area quanta are expanding or oscillating in time.
Modeling Space-Time Dynamics of Aerosols Using Satellite Data and Atmospheric Transport Model Output
Shi, Tao
Modeling Space-Time Dynamics of Aerosols Using Satellite Data and Atmospheric Transport Model of aerosol optical depth across mainland Southeast Asia. We include a cross validation study to assess
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
Temporal variations in space-time and progenitors of gamma ray burst and millisecond pulsars
Preston Jones
2007-08-31T23:59:59.000Z
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
2015-01-01T23:59:59.000Z
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.
High-Fidelity Space-Time Adaptive Multiphysics Simulations in Nuclear Engineering
Solin, Pavel; Ragusa, Jean
2014-05-21T23:59:59.000Z
Monolithic adaptive multimesh hp-FEM discretization of multiphysics coupled problems Monolithic coupling of hp-FEM and hp-DG methods New modular approach to higher-order time discretization of transient PDE problems
Space-Time Models based on Random Fields with Local Interactions
Dionissios T. Hristopulos; Ivi C. Tsantili
2015-03-06T23:59:59.000Z
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.
Abe, Yasumi [Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801 (Japan)
2008-06-15T23:59:59.000Z
The space-time symmetry of noncommutative quantum field theories with a deformed quantization is described by the twisted Poincare algebra, while that of standard commutative quantum field theories is described by the Poincare algebra. Based on the equivalence of the deformed theory with a commutative field theory, the correspondence between the twisted Poincare symmetry of the deformed theory and the Poincare symmetry of a commutative theory is established. As a by-product, we obtain the conserved charge associated with the twisted Poincare transformation to make the twisted Poincare symmetry evident in the deformed theory. Our result implies that the equivalence between the commutative theory and the deformed theory holds in a deeper level, i.e., it holds not only in correlation functions but also in (different types of) symmetries.
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
Lifshitz field theories, Snyder noncomutative space-time and momentum dependent metric
Romero, Juan M
2015-01-01T23:59:59.000Z
In this work, we propose three different modified relativistic particles. In the first case, we propose a particle with metrics depending on the momenta and we show that the quantum version of these systems includes different field theories, as anisotropic field theories. As a second case we propose a particle that implies a modified symplectic structure and we show that the quantum version of this system gives different noncommutative space-times, for example the Snyder space-time. In the third case, we combine both structures before mentioned, namely noncommutative space-times and momentum dependent metrics. In this last case, we show that anisotropic field theories can be seen as a limit of no commutative field theory.
P. Danielewicz
2006-07-15T23:59:59.000Z
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.
Upper bound for entropy in asymptotically de Sitter space-time
Kengo Maeda; Tatsuhiko Koike; Makoto Narita; Akihiro Ishibashi
1997-12-05T23:59:59.000Z
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
2014-11-29T23:59:59.000Z
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.
Non-trivial, static, geodesically complete, vacuum space-times with a negative cosmological constant
Avignon et des Pays de Vaucluse, Université de
Non-trivial, static, geodesically complete, vacuum space-times with a negative cosmological singularity-free static Lorentzian four- dimensional solutions of the vacuum Einstein equations of this paper is to show that such rigidity is false in this last situation. More precisely, for
Non-trivial, static, geodesically complete, vacuum space-times with a negative cosmological constant
Anderson, Michael
Non-trivial, static, geodesically complete, vacuum space-times with a negative solutions of the vacuum Einstein equations with a negative cosmological constant. The new families of this paper is to show that such rigidity is false in this last situation. More precisely, for
Non-trivial, static, geodesically complete, vacuum space-times with a negative cosmological constant
Anderson, Michael
Non-trivial, static, geodesically complete, vacuum space-times with a negative cosmological construct a large class of new singularity-free static Lorentzian four- dimensional solutions of the vacuum is false in this last situation. More precisely, for #3;
The stability of Killing-Cauchy horizons in colliding plane wave space-times
J. B. Griffiths
2005-01-05T23:59:59.000Z
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.
Dynamics on the Way to Forming Glass: Bubbles in Space-time David Chandler1
Chandler, David
Dynamics on the Way to Forming Glass: Bubbles in Space-time David Chandler1 and Juan P. Garrahan2 1 a theoretical perspective of the dynamics of glass forming liquids and the glass tran- sition of trajectory space. This structure emerges from spatial correlations of dynamics that appear in disordered
ON-LINE DETECTION OF DISTRIBUTED ATTACKS FROM SPACE-TIME NETWORK FLOW PATTERNS
Baras, John S.
ON-LINE DETECTION OF DISTRIBUTED ATTACKS FROM SPACE-TIME NETWORK FLOW PATTERNS J.S. Baras* , A in the network. We are interested in the "quickest detection" problem when the attack is distributed is to detect when a distributed denial of service is taking place in one sub-network of a transit (core
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
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
Photons with sub-Planckian Energy Cannot Efficiently Probe Space-Time Foam
Yanbei Chen; Linqing Wen; Yiqiu Ma
2015-04-24T23:59:59.000Z
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.
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
The Yang-Mills gauge theory in DFR noncommutative space-time
Abreu, Everton M C
2015-01-01T23:59:59.000Z
The Doplicher-Fredenhagen-Roberts (DFR) framework for noncommutative (NC) space-times is considered as an alternative approach to describe the physics of quantum gravity, for instance. In this formalism, the NC parameter, {\\it i.e.} $\\theta^{\\mu\
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
Powering Up With Space-Time Wind Forecasting Amanda S. HERING and Marc G. GENTON
Genton, Marc G.
Powering Up With Space-Time Wind Forecasting Amanda S. HERING and Marc G. GENTON The technology to harvest electricity from wind energy is now advanced enough to make entire cities powered by it a reality be more realistically assessed with a loss measure that depends upon the power curve relating wind speed
Distributional Energy-Momentum Tensor of the Kerr-Newman Space-Time Family
Herbert Balasin; Herbert Nachbagauer
1993-12-17T23:59:59.000Z
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.
Iterative Spatial Sequence Estimator for Multi-Group Space Time Trellis Coded Systems
Al-Ghadhban, Samir
Iterative Spatial Sequence Estimator for Multi-Group Space Time Trellis Coded Systems Samir Al. The developed detector is called maximum a posteriori spatial sequence estimator and it has the flexibility. A novel spatial sequence estimator (SSE) for V-BLAST is proposed in [4]. The algorithm combines group
Space-Time Stereo James DavisJames Davis Honda Research InstituteHonda Research Institute
O'Brien, James F.
Space-Time Stereo James DavisJames Davis ÂÂ Honda Research InstituteHonda Research Institute Ravi ÂÂ Princeton UniversityPrinceton University DiegoDiego NehabNehab ÂÂ Honda & PrincetonHonda & Princeton
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
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
Photon emission in a constant magnetic field in 2+1 dimensional space-time
J. T. S. Amaral; S. I. Zlatev
2005-11-01T23:59:59.000Z
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 space-time BIE method for wave equation exterior problems. The Neumann case.
Ceragioli, Francesca
A space-time BIE method for wave equation exterior problems. The Neumann case. S. Falletta , G. Monegato , L. ScuderiÂ§ Abstract In this paper we consider the (2D and 3D) exterior problem for the wave equation, with a Neumann boundary condition and in general with non trivial data. First we derive a space
A Space-Time Finite Element Method for the Exterior Structural Acoustics Problem
Thompson, Lonny L.
A Space-Time Finite Element Method for the Exterior Structural Acoustics Problem: Time-time finite element method is formu- lated for the exterior structural acoustics problem in two space formulation is presented for solution of the exterior struc- tural acoustics problem in two space dimensions
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
Sergey V. Yakovlev
2011-12-21T23:59:59.000Z
Were investigated anisotropic metric of higher dimensional space-time with only cosmological term and scalar field. Showed, that presence of scalar field is equivalent to anisotropic metric in the multy dimensional space-time and proposed idea of dimensions generation by scalar field. Were solved Einstein's equations for higher dimensional space-time of Kazner's type and derived expressions for density of energy for scalar field, which generate additional dimensions, and proposed the procedure of renormalization of the metric.
Eva Hackmann; Claus Lämmerzahl
2015-05-29T23:59:59.000Z
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
2015-01-01T23:59:59.000Z
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.
Perturbative quantization of two-dimensional space-time noncommutative QED
Ghasemkhani, M.; Sadooghi, N. [Department of Physics, Sharif University of Technology, P.O. Box 11155-9161, Tehran (Iran, Islamic Republic of)
2010-02-15T23:59:59.000Z
Using the method of perturbative quantization in the first order approximation, we quantize a nonlocal QED-like theory including fermions and bosons whose interactions are described by terms containing higher order space-time derivatives. As an example, the two-dimensional space-time noncommutative QED (NC-QED) is quantized perturbatively up to O(e{sup 2},{theta}{sup 3}), where e is the NC-QED coupling constant and {theta} is the noncommutativity parameter. The resulting modified Lagrangian density is shown to include terms consisting of first order time-derivative and higher order space-derivatives of the modified field variables that satisfy the ordinary equal-time commutation relations up to O(e{sup 2},{theta}{sup 3}). Using these commutation relations, the canonical current algebra of the modified theory is also derived.
On the extension of Newton's second law to theories of gravitation in curved space-time
Mayeul Arminjon
2006-09-14T23:59:59.000Z
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.
Continuous time random walk models for fractional space-time diffusion equations
Sabir Umarov
2014-09-14T23:59:59.000Z
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.
The Energy Distribution in a Static Spherically Symmetric Nonsingular Black Hole Space-Time
I. Radinschi
2000-08-14T23:59:59.000Z
We calculate the energy distribution in a static spherically symmetric nonsingular black hole space-time by using the Tolman's energy-momentum complex. All the calculations are performed in quasi-Cartesian coordinates. The energy distribution is positive everywhere and be equal to zero at origin. We get the same result as obtained by Y-Ching Yang by using the Einstein's and Weinberg's prescriptions.
Space-time curvature due to quantum vacuum fluctuations: An alternative to dark energy?
Santos, Emilio
2010-01-01T23:59:59.000Z
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
2009-12-30T23:59:59.000Z
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.
Complete analytic solution of the geodesic equation in Schwarzschild--(anti) de Sitter space--times
Eva Hackmann; Claus Lämmerzahl
2015-05-29T23:59:59.000Z
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.
Generalized strong curvature singularities and weak cosmic censorship in cosmological space-times
W. Rudnicki; R. J. Budzynski; W. Kondracki
2006-06-01T23:59:59.000Z
This paper is a further development of the approach to weak cosmic censorship proposed by the authors in Ref. 5. We state and prove a modified version of that work's main result under significantly relaxed assumptions on the asymptotic structure of space--time. The result, which imposes strong constraints on the occurrence of naked singularities of the strong curvature type, is in particular applicable to physically realistic cosmological models.
TASI Lectures on Holographic Space-Time, SUSY and Gravitational Effective Field Theory
Tom Banks
2010-09-23T23:59:59.000Z
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 $K \\Lambda^{1/4}$.
A Non-Riemannian Metric on Space-Time Emergent From Scalar Quantum Field Theory
Kar, Arnab
2012-01-01T23:59:59.000Z
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 ...
Asymptotically Stationary and Static Space-times and Shear-free Null Geodesic Congruences
T. M. Adamo; E. T. Newman
2009-06-12T23:59:59.000Z
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.
Cosmological perturbations in the (1+3+6)-dimensional space-times
Kenji Tomita
2014-12-20T23:59:59.000Z
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.
Lovley, Derek
on the hardest of hardware: photovoltaics (solar panels), hydrogen fuel cells, radioisotope thermal generatorsPower In Space: Time For A Biological Solution http://www.spacedaily.com/reports/Power_In_Space_Time_For_A_Bi... 1 of 4 5/16/2007 10:16 AM Conceptual drawing of a Mars base based on bio-power. A greenhouse
Xavier Busch
2014-11-06T23:59:59.000Z
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.
None
2011-10-06T23:59:59.000Z
- 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
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
Discrete Scale Relativity And SX Phoenicis Variable Stars
R. L. Oldershaw
2009-06-18T23:59:59.000Z
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.
Cao H. Nam
2014-11-10T23:59:59.000Z
We consider the space-time at short distances in which it is described by a $D$-dimensional manifold (bulk) carrying out the principal bundle structure. As a result, this space-time manifold is foliated in the covariant way by the $(D-4)$-dimensional submanifolds, realized as the space-like internal spaces, that are smooth copies of the Lie group $G$ considered in this paper as the special unitary group. The submanifolds being transversal to the internal spaces are realized as the external spaces and in fact identified as the usual $4$-dimensional world. The fundamental degrees of freedom determining the geometrical dynamics of the bulk corresponding with short distance gravity are given by the gauge fields, the external metric field and the modulus fields setting dynamically the volume of the internal spaces. These gauge fields laying the bulk is to point precisely out the local directions of the external spaces which depend on the topological non-triviality of the space-time principal bundle. The physical size of the internal spaces is fixed dynamically by the moduli stabilization potential which completely arise from the intrinsic geometry of the bulk. A detail description of the low energy bulk gravity in the weak field limit is given around the classical ground state of the bulk. Additionally, we investigate the dynamics of the fundamentally $4$-dimensional Weyl spinor fields and the fields of carrying out the non-trivial representations of the Lie group $G$ propagating in the bulk in a detail study. These results suggest naturally the possible solutions to some the experimental problems of Standard Model, the smallness of the observed neutrino masses and a dark matter candidate.
Knot Topology of Vacuum Space-Time and Vacuum Decomposition of Einstein's Theory
Y. M. Cho; Franklin H. Cho
2011-10-28T23:59:59.000Z
Viewing Einstein's theory as the gauge theory of Lorentz group, we construct the most general vacuum connections which have vanishing curvature tensor and show that the vacuum space-time can be classified by the knot topology $\\pi_3(S^3)\\simeq \\pi_3(S^2)$ of $\\pi_3(SO(3,1))$. With this we obtain the gauge independent vacuum decomposition of Einstein's theory to the vacuum and gauge covariant physical parts. We discuss the physical implications of our result in quantum gravity.
Energy of gravitational radiation in plane-symmetric space-times
Sean A. Hayward
2008-05-19T23:59:59.000Z
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.
Fuzzy Geometry via the Spinor Bundle, with Applications to Holographic Space-time and Matrix Theory
Tom Banks; John Kehayias
2011-11-02T23:59:59.000Z
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.
On the local form of static plane symmetric space-times in the presence of matter
Leandro G. Gomes
2015-02-10T23:59:59.000Z
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
2015-05-13T23:59:59.000Z
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.
N. Seiberg; L. Susskind; N. Toumbas
2000-05-04T23:59:59.000Z
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.
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)
2013-03-01T23:59:59.000Z
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.
Energy and Momentum Distributions of Kantowski and Sachs Space-time
Ragab M. Gad; A. Fouad
2007-04-15T23:59:59.000Z
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.
Biquaternion Electrodynamics and Weyl-Cartan Geometry of Space-Time
V. V. Kassandrov
2000-07-13T23:59:59.000Z
The generalized Cauchy-Riemann equations (GCRE) in biquaternion algebra appear to be Lorentz-invariant. The Laplace equation is in this case replaced by a nonlinear (complexified) eikonal equation. GCRE contain the 2-spinor and the gauge structures, and their integrability conditions take the form of free-source Maxwell and Yang-Mills equations. For the value of electric charge from GCRE only the quantization rule follows, as well as the treatment of Coulomb law as a stereographic map. The equivalent geometrodynamics in a Weyl-Cartan affine space and the conjecture of a complex-quaternion structure of space-time are discussed.
O. Babelon; D. Bernard
1991-11-20T23:59:59.000Z
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.
Self-force on an arbitrarily coupled static scalar particle in a wormhole space-time
Peter Taylor
2012-10-20T23:59:59.000Z
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.
Hossein Ghaffarnejad
2015-04-29T23:59:59.000Z
Aim of the paper is to obtain 2d analogue of the backreaction equation which will be useful to study final state of quantum perturbed spherically symmetric curved space times. Thus we take Einstein-massless-scalar $\\psi$ tensor gravity model described on class of spherically symmetric curved space times. We rewrite the action functional in 2d analogue in terms of dimensionless dilaton-matter field $(\\chi=\\Phi\\psi)$ where dilaton field $\\Phi$ is conformal factor of 2-sphere. Then we seek renormalized expectation value of quantum dilaton-matter field stress tensor operator by applying Hadamard rennormalization prescription. Singularity of the Green function is assumed to be has logarithmic form. Covariantly conservation condition on the renormalized quantum dilaton-matter stress tensor demands to input a variable cosmological parameter $\\lambda(x)$. Energy conditions (weak, strong and null) is studied on the obtained renormalized stress tensor leading to dynamical equations for $\\lambda(x), \\Phi$ and quantum vacuum state $W_0(x)=_{ren}.$ In weak quantum field limits our obtained trace anomaly corresponds to one which obtained from zeta function regularization method. Setting null-like apparent horizon equation $\
Saskia Grunau; Valeria Kagramanova
2010-11-24T23:59:59.000Z
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.
Doppler Effects from Bending of Light Rays in Curved Space-Times
Matteo Luca Ruggiero; Angelo Tartaglia; Lorenzo Iorio
2006-05-06T23:59:59.000Z
We study Doppler effects in curved space-time, i.e. the frequency shifts induced on electromagnetic signals propagating in the gravitational field. In particular, we focus on the frequency shift due to the bending of light rays in weak gravitational fields. We consider, using the PPN formalism, the gravitational field of an axially symmetric distribution of mass. The zeroth order, i.e. the sphere, is studied then passing to the contribution of the quadrupole moment, and finally to the case of a rotating source. We give numerical estimates for situations of physical interest, and by a very preliminary analysis, we argue that analyzing the Doppler effect could lead, in principle, in the foreseeable future, to the measurement of the quadrupole moment of the giant planets of the Solar System.
Energy dependence of space-time extent of pion source in nuclear collisions
Okorokov, V A
2015-01-01T23:59:59.000Z
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.
Holographic Space-time and Black Holes: Mirages As Alternate Reality
Tom Banks; Willy Fischler; Sandipan Kundu; Juan F. Pedraza
2014-01-30T23:59:59.000Z
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.
S. G. Matinyan; B. Mueller; D. H. Rischke
1997-08-28T23:59:59.000Z
We investigate the space-time structure of the classical gluon field produced in an ultrarelativistic collision between color charges. The classical solution which was computed previously in a perturbative approach is shown to become unstable on account of the non-Abelian self-interaction neglected in the perturbative solution scheme. The time scale for growth of the instabilities is found to be of the order of the distance between the colliding color charges. We argue that these instabilities will eventually lead to thermalization of gluons produced in an ultrarelativistic collision between heavy nuclei. The rate of thermalization is estimated to be of order $g^2 \\mu$, where $g$ is the strong coupling constant and $\\mu^2$ the transverse color charge density of an ultrarelativistic nucleus.
On Non-Equilibrium Thermodynamics of Space-Time and Quantum Gravity
Joakim Munkhammar
2015-07-02T23:59:59.000Z
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.
Renormalized Free Energy on Space-time with Compact Hyperbolic Spatial Part
Rosevaldo de Oliveira
2010-05-19T23:59:59.000Z
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
2015-04-19T23:59:59.000Z
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.
Five-Dimensional Tangent Vectors in Space-Time: IV. Generalization of Exterior Calculus
Alexander Krasulin
1998-08-18T23:59:59.000Z
This part of the series is devoted to the generalization of exterior differential calculus. I give definition to the integral of a five-vector form over a limited space-time volume of appropriate dimension; extend the notion of the exterior derivative to the case of five-vector forms; and formulate the corresponding analogs of the generalized Stokes theorem and of the Poincare theorem about closed forms. I then consider the five-vector generalization of the exterior derivative itself; prove a statement similar to the Poincare theorem; define the corresponding five-vector generalization of flux; and derive the analog of the formula for integration by parts. I illustrate the ideas developed in this paper by reformulating the Lagrange formalism for classical scalar fields in terms of five-vector forms. In conclusion, I briefly discuss the five-vector analog of the Levi-Civita tensor and dual forms.
Muhammad Nadeem
2015-05-07T23:59:59.000Z
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.
Energy dependence of space-time extent of pion source in nuclear collisions
V. A. Okorokov
2015-04-30T23:59:59.000Z
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.
Origin of matter and space-time in the big bang
Mathews, G. J. [University of Notre Dame, Center for Astrophysics/JINA, Notre Dame, IN 46556, USA and Division of Theoretical Astronomy, National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Kajino, T. [Division of Theoretical Astronomy, National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan and Department of Astronomy, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Yamazaki, D. [Division of Theoretical Astronomy, National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Kusakabe, M. [School of Liberal Arts and Science, Korea Aerospace University, Goyang 412-791, Korea and Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of); Cheoun, M.-K. [Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of)
2014-05-02T23:59:59.000Z
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
2015-05-05T23:59:59.000Z
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.
Generalized discrete orbit function transforms of affine Weyl groups
Tomasz Czy?ycki; Ji?í Hrivnák
2014-11-14T23:59:59.000Z
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.
Lee, Ming S.; McNally, Michael G.
2002-01-01T23:59:59.000Z
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
Spinning particles in vacuum space-times of different curvature types -- I
Semerák, O
2015-01-01T23:59:59.000Z
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 typ...
Automorphic Lie Algebras with dihedral symmetry
Vincent Knibbeler; Sara Lombardo; Jan A Sanders
2014-10-10T23:59:59.000Z
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.
Discrete Symmetry in the EPRL Model and Neutrino Physics
Louis Crane
2011-05-30T23:59:59.000Z
In \\cite{C1}, we proposed a new interpretation of the EPRL quantization of the BC model for quantum general relativity using a monoidal functor we call the time functor. In this preliminary draft we apply the theory of modules over monoidal functors \\cite{Y1} to the time functor, to propose an extension of the EPRL model which would include the standard model. This is motivated by recent advances in neutrino Physics.
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
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
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
$K_S$ semileptonic decays and test of $\\mathcal{CPT}$ symmetry with the KLOE detector
D. Kami?ska
2015-01-19T23:59:59.000Z
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
2015-05-27T23:59:59.000Z
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.
Roelof Bijker
2005-09-02T23:59:59.000Z
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.
Gupalo, D.; Kaganovich, A.S.; Cohen, E.G.D. (Rockefeller Univ., New York, NY (United States))
1994-03-01T23:59:59.000Z
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.
A discrete fractional random transform
Zhengjun Liu; Haifa Zhao; Shutian Liu
2006-05-20T23:59:59.000Z
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.
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
Noncommutative Geometry and a Discretized Version of Kaluza-Klein Theory with a Finite Field Content
Nguyen Ai Viet; Kameshwar C. Wali
1994-12-27T23:59:59.000Z
We consider a four-dimensional space-time supplemented by two discrete points assigned to a $Z_2$ algebraic structure and develop the formalism of noncommutative geometry. By setting up a generalised vielbein, we study the metric structure. Metric compatible torsion free connection defines a unique finite field content in the model and leads to a discretized version of Kaluza-Klein theory. We study some special cases of this model that illustrate the rich and complex structure with massive modes and the possible presence of a cosmological constant.
Classical Symmetries of Some Two-Dimensional Models
John H. Schwarz
1995-03-27T23:59:59.000Z
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.
Bulk photons in Asymmetrically Warped Space-times and Non-trivial Vacuum Refractive Index
K. Farakos; N. E. Mavromatos; P. Pasipoularides
2009-01-20T23:59:59.000Z
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.
Majorana-Oppenheimer approach to Maxwell electrodynamics in Riemannian space-time
Bogush, A; Tokarevskaya, N; Spix, G
2009-01-01T23:59:59.000Z
The Riemann -- Silberstein -- Majorana -- Oppengeimer approach to the Maxwell electrodynamics in presence of electrical sources and arbitrary media is investigated within the matrix formalism. The symmetry of the matrix Maxwell equation under transformations of the complex rotation group SO(3.C) is demonstrated explicitly. In vacuum case, the matrix form includes four real $4 \\times 4$ matrices $\\alpha^{b}$. In presence of media matrix form requires two sets of $4 \\times 4$ matrices, $\\alpha^{b}$ and $\\beta^{b}$ -- simple and symmetrical realization of which is given. Relation of $\\alpha^{b}$ and $\\beta^{b}$ to the Dirac matrices in spinor basis is found. Minkowski constitutive relations in case of any linear media are given in a short algebraic form based on the use of complex 3-vector fields and complex orthogonal rotations from SO(3.C) group. The matrix complex formulation in the Esposito's form, based on the use of two electromagnetic 4-vector, is studied and discussed. Extension of the 3-vector complex m...
Effect of the electric field on the creation of fermions in de-Sitter space-time
Haouat, S
2015-01-01T23:59:59.000Z
The effect of the electric field on the creation of spin 1/2 particles from vacuum in the (1+1) dimensional de-Sitter space-time is studied. The Dirac equation with a constant electric field is solved by introducing an unitary transformation. Then the canonical method based on Bogoliubov transformation is applied to calculate the pair creation probability and the density of created particles both for positive or negative wave vector. By doing summation over all allowed states, the number of created particles per unit of time per unit of length and the imaginary part of the Schwinger effective action are expressed in closed forms. It is shown that the electric field leads to a significant enhancement of the particle creation. The weak expansion case and the limit H=0, where dS space reduces to the flat Minkowski space-time, are discussed.
Belavin, Alexander
2015-01-01T23:59:59.000Z
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
1998-01-29T23:59:59.000Z
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.
Asan Damanik
2010-11-25T23:59:59.000Z
Neutrino mass matrix via a seesaw mechanism is constructed by assuming that the underlying symmetry of both heavy Majorana and Dirac mass matrices is the discrete subgroup $\\Delta(27)$ symmetry of SU(3). Using the experimental data of neutrino oscillation, the neutrino mass matrix exhibits maximal $\
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
Roy Maartens; David Taylor
1997-12-11T23:59:59.000Z
We define affine transport lifts on the tangent bundle by associating a transport rule for tangent vectors with a vector field on the base manifold. The aim is to develop tools for the study of kinetic/ dynamical symmetries in relativistic particle motion. The transport lift unifies and generalises the various existing lifted vector fields, with clear geometric interpretations. We find the affine dynamical symmetries of free particle motion, and compare this to previous results and to the alternative concept of "matter symmetry".
Sekhar Chivukula
2010-01-08T23:59:59.000Z
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.
Discrete multivariate distributions
Oleg Yu. Vorobyev; Lavrentiy S. Golovkov
2011-02-22T23:59:59.000Z
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
Symmetry and Topological Order
Zohar Nussinov; Gerardo Ortiz
2014-10-22T23:59:59.000Z
We prove sufficient conditions for Topological Quantum Order at both zero and finite temperatures. The crux of the proof hinges on the existence of low-dimensional Gauge-Like Symmetries (that notably extend and differ from standard local gauge symmetries) and their associated defects, thus providing a unifying framework based on a symmetry principle. These symmetries may be actual invariances of the system, or may emerge in the low-energy sector. Prominent examples of Topological Quantum Order display Gauge-Like Symmetries. New systems exhibiting such symmetries include Hamiltonians depicting orbital-dependent spin exchange and Jahn-Teller effects in transition metal orbital compounds, short-range frustrated Klein spin models, and p+ip superconducting arrays. We analyze the physical consequences of Gauge-Like Symmetries (including topological terms and charges), discuss associated braiding, and show the insufficiency of the energy spectrum, topological entanglement entropy, maximal string correlators, and fractionalization in establishing Topological Quantum Order. General symmetry considerations illustrate that not withstanding spectral gaps, thermal fluctuations may impose restrictions on certain suggested quantum computing schemes and lead to "thermal fragility". Our results allow us to go beyond standard topological field theories and engineer systems with Topological Quantum Order.
Differential Geometry: Discrete Exterior Calculus
Kazhdan, Michael
Differential Geometry: Discrete Exterior Calculus [Build Your Own DEC at Home. Elcott et al., 2006] [Discrete Differential Forms for Computational Modeling. Desbrun et al., 2005] [Discrete Exterior Calculus-simplices in : where c is a real-valued function. The space of k-chains is denoted Ck(). = k cc )( #12;Chains
1+1+2 gravitational perturbations on LRS class II space-times: GEM scalar harmonic amplitudes
R. B. Burston
2007-08-19T23:59:59.000Z
This is the third in a series of papers which considers first-order gauge-invariant and covariant gravitational perturbations to locally rotationally symmetric (LRS) class II space-times. In this paper we complete our analysis of the first-order gravito-electromagnetic (GEM) system by showing how to derive three decoupled equations governing the GEM scalar fields. One of these is for the gravito-magnetic scalar, whereas another two arise from the 2-gradient of the gravito-electric scalar.
Lorentz symmetry breaking in the noncommutative Wess-Zumino model: One loop corrections
Ferrari, A.F.; Gomes, M.; Girotti, H.O. [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, 05315-970, Sao Paulo - SP (Brazil); Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, 91501-970 - Porto Alegre, RS (Brazil)
2006-02-15T23:59:59.000Z
In this paper we deal with the issue of Lorentz symmetry breaking in quantum field theories formulated in a noncommutative space-time. We show that, unlike in some recent analysis of quantum gravity effects, supersymmetry does not protect the theory from the large Lorentz-violating effects arising from the loop corrections. We take advantage of the noncommutative Wess-Zumino model to illustrate this point.
R. B. Burston; A. W. C. Lun
2007-08-14T23:59:59.000Z
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
2012-06-28T23:59:59.000Z
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
2012-01-01T23:59:59.000Z
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.
John H. Schwarz
1995-03-20T23:59:59.000Z
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.
Miller, G.A. [Department of Physics, FM-15, University of Washington, Seattle, Washington 98195 (United States)
1995-07-15T23:59:59.000Z
Charge independence and symmetry are approximate symmetries of nature. The observations of the small charge symmetry breaking effects and the consequences of those effects are reviewed. The effects of the mass difference between up and down quarks and the off shell dependence {ital q}{sup 2} of {rho}{sup 0}-{omega} mixing are stressed. We find that models which predict a strong {ital q}{sup 2} dependence of {rho}{sup 0}-{omega} mixing seem also to predict a strong {ital q}{sup 2} variation for the {rho}{sup 0}-{gamma}* matrix element, in contradiction with experiment.
Dilaton: Saving Conformal Symmetry
Frederic Gretsch; Alexander Monin
2013-08-18T23:59:59.000Z
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.
Polymer quantization and Symmetries
Ghanashyam Date; Nirmalya Kajuri
2013-02-24T23:59:59.000Z
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.
Symmetry in Scheduling Problems
2010-11-16T23:59:59.000Z
Nov 16, 2010 ... Using operating room and power generator scheduling problems ... suggested that a class of highly symmetric covering problems called Steiner Triple Systems ... The structure of symmetry present in these problems allow for.
Symmetries in Integer Programs
Bödi, R
2009-01-01T23:59:59.000Z
The notion of symmetry is defined in the context of Linear and Integer Programming. Symmetric integer programs are studied from a group theoretical viewpoint. We investigate the structure of integer solutions of integer programs and show that any integer program on n variables having an alternating group A_n as a group of symmetries can be solved in linear time in the number of variables.
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
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
2015-01-01T23:59:59.000Z
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...
Sawa Manoff
2003-09-09T23:59:59.000Z
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.
Energy-Momentum Localization for a Space-Time Geometry Exterior to a Black Hole in the Brane World
Irina Radinschi; Theophanes Grammenos; Andromahi Spanou
2012-05-20T23:59:59.000Z
In general relativity one of the most fundamental issues consists in defining a generally acceptable definition for the energy-momentum density. As a consequence, many coordinate-dependent definitions have been presented, whereby some of them utilize appropriate energy-momentum complexes. We investigate the energy-momentum distribution for a metric exterior to a spherically symmetric black hole in the brane world by applying the Landau-Lifshitz and Weinberg prescriptions. In both the aforesaid prescriptions, the energy thus obtained depends on the radial coordinate, the mass of the black hole and a parameter $\\lambda_{0}$, while all the momenta are found to be zero. It is shown that for a special value of the parameter $\\lambda_{0}$, the Schwarzschild space-time geometry is recovered. Some particular and limiting cases are also discussed.
1+1+2 gravitational perturbations on LRS class II space-times: GEM vector harmonic amplitudes
R. B. Burston
2007-08-19T23:59:59.000Z
This is the second in a series of papers which considers first-order gauge-invariant and covariant gravitational perturbations to locally rotationally symmetric (LRS) class II space-times. This paper shows how to decouple a complex combination of the gravito-electromagnetic (GEM) 2-vectors with the 2-tensors describing the shear of the 2/3-sheets. An arbitrary harmonic expansion is then used along with an eigen-vector/value analysis of the first-order GEM system, analogous to the first paper in this series. This results in four real decoupled equations governing four real combinations of the harmonic amplitudes of the GEM 2-vectors and the (2/3-sheet) shear 2-tensors. Finally, these are categorized into polar and axial perturbations.
Thermodynamics of discrete quantum processes
Janet Anders; Vittorio Giovannetti
2012-11-01T23:59:59.000Z
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.
Damanik, Asan
2010-01-01T23:59:59.000Z
Neutrino mass matrix via a seesaw mechanism is constructed by assuming that the underlying symmetry of both heavy Majorana and Dirac mass matrices is the discrete subgroup $\\Delta(27)$ symmetry of $SU(3)$. Using the experimental data of neutrino oscillation, the neutrino mass matrix exhibits maximal $\
Thomas D. Cohen
2009-11-16T23:59:59.000Z
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.
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
FPGA Acceleration of Discrete Molecular Dynamics Simulation
Herbordt, Martin
' & $ % FPGA Acceleration of Discrete Molecular Dynamics Simulation Joshua Model Thesis submitted UNIVERSITY COLLEGE OF ENGINEERING Thesis FPGA Acceleration of Discrete Molecular Dynamics Simulation Acceleration of Discrete Molecular Dynamics Simulation Joshua Model ABSTRACT Molecular dynamics simulation
Eugene V. Stefanovich
2015-02-16T23:59:59.000Z
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.
R. B. Burston
2007-08-14T23:59:59.000Z
This paper considers gauge-invariant and covariant gravitational perturbations on arbitrary vacuum locally rotationally symmetric (LRS) class II space-times. Ultimately, we derive four decoupled equations governing four specific combinations of the gravito-electromagnetic (GEM) 2-tensor harmonic amplitudes. We use the gauge-invariant and covariant 1+1+2 formalism which Clarkson and Barrett developed for analysis of vacuum Schwarzschild perturbations. In particular we focus on the first-order 1+1+2 GEM system and use linear algebra techniques suitable for exploiting its structure. Consequently, we express the GEM system new 1+1+2 complex form by choosing new complex GEM tensors, which is conducive to decoupling. We then show how to derive a gauge-invariant and covariant decoupled equation governing a newly defined complex GEM 2-tensor. Finally, the GEM 2-tensor is expanded in terms of arbitrary tensor harmonics and linear algebra is used once again to decouple the system further into 4 real decoupled equations.
John H. Schwarz
1992-09-29T23:59:59.000Z
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.
Finsler manifolds with general symmetries
Latifi, Dariush
2012-01-01T23:59:59.000Z
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.
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)
2006-06-19T23:59:59.000Z
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.
Gauging the twisted Poincare symmetry as a noncommutative theory of gravitation
Chaichian, M.; Tureanu, A. [Department of Physics, University of Helsinki, P.O. Box 64, FIN-00014 Helsinki (Finland); Helsinki Institute of Physics, P.O. Box 64, FIN-00014 Helsinki (Finland); Oksanen, M. [Department of Physics, University of Helsinki, P.O. Box 64, FIN-00014 Helsinki (Finland); Zet, G. [Department of Physics, 'Gh. Asachi' Technical University, Bd. D. Mangeron 67, 700050 Iasi (Romania)
2009-02-15T23:59:59.000Z
Einstein's theory of general relativity was formulated as a gauge theory of Lorentz symmetry by Utiyama in 1956, while the Einstein-Cartan gravitational theory was formulated by Kibble in 1961 as the gauge theory of Poincare transformations. In this framework, we propose a formulation of the gravitational theory on canonical noncommutative space-time by covariantly gauging the twisted Poincare symmetry, in order to fulfil the requirement of covariance under the general coordinate transformations, an essential ingredient of the theory of general relativity. It appears that the twisted Poincare symmetry cannot be gauged by generalizing the Abelian twist to a covariant non-Abelian twist, nor by introducing a more general covariant twist element. The advantages of such a formulation as well as the related problems are discussed and possible ways out are outlined.
Symmetry Energy in Nuclear Surface
Pawel Danielewicz; Jenny Lee
2008-12-25T23:59:59.000Z
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.
Gravitational Collapse In Husain Space-time For Brans-Dicke Gravity Theory with Power-law Potential
Prabir Rudra; Ritabrata Biswas; Ujjal Debnath
2014-08-18T23:59:59.000Z
The motive of this work is to study gravitational collapse in Husain space-time in Brans-Dicke gravity theory. Among many scalar-tensor theories of gravity, Brans-Dicke is the simplest and the impact of it can be regulated by two parameters associated with it, namely, the Brans-Dicke parameter, $\\omega$, and the potential-scalar field dependency parameter $n$ respectively. V. Husain's work on exact solution for null fluid collapse in 1996 has influenced many authors to follow his way to find the end-state of the homogeneous/in-homogeneous dust cloud. Vaidya's metric is used all over to follow the nature of future outgoing radial null geodesics. Detecting whether the central singularity is naked or wrapped by an event horizon, by the existence of future directed radial null geodesic emitted in past from the singularity is the basic objective. To point out the existence of positive trajectory tangent solution, both particular parametric cases(through tabular forms) and wide range contouring process have been applied. Precisely, perfect fluid's EoS satisfies a wide range of phenomena : from dust to exotic fluid like dark energy. We have used the EoS parameter $k$ to determine the end state of collapse in different cosmological era. Our main target is to check low $\\omega$ (more deviations from Einstein gravity-more Brans Dicke effect) and negative $k$ zones. This particularly throws light on the nature of the end-state of collapse in accelerated expansion in Brans Dicke gravity. It is seen that for positive values of EoS parameter $k$, the collapse results in a black hole, whereas for negative values of $k$, naked singularity is the only outcome. It is also to be noted that "low $\\omega$" leads to the possibility of getting more naked singularities even for a non-accelerating universe.
Felix Hovsepian
2007-11-08T23:59:59.000Z
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.
International Symposium on Discrete Mathematics
University, China Ghent University, Belgium CAS-MPG Partner Institute for Computational Biology, ChinaInternational Symposium on Discrete Mathematics and Mathematical Biology August 2627, 2013 Find Interdisciplinary Centre for Bioinformatics #12;
Mass independent textures and symmetry
Lam, C. S. [Department of Physics, McGill University, Montreal, QC, Canada H3A 2T8 and Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1 (Canada)
2006-12-01T23:59:59.000Z
A mass-independent texture is a set of linear relations of the fermion mass-matrix elements which imposes no constraint on the fermionic masses nor the Majorana phases. Magic and 2-3 symmetries are examples. We discuss the general construction and the properties of these textures, as well as their relation to the quark and neutrino mixing matrices. Such a texture may be regarded as a symmetry, whose unitary generators of the symmetry group can be explicitly constructed. In particular, the symmetries connected with the tribimaximal neutrino mixing matrix are discussed, together with the physical consequence of breaking one symmetry but preserving another.
Ping, Li
can be used to significantly increase the reliability and spectrum efficiency of wireless approach so as to ensure reliability, such as in the vertical Bell Laboratories layered spacetime (V antennas. The BLAST architectures are less effective in multiple-inputsingle-output (MISO) environments
Presented by Parallel Discrete Event Simulation
of discrete event execution on high performance computing Business Sensitive · Different optimizations
Symmetries in open quantum dynamics
Thomas F. Jordan
2014-08-20T23:59:59.000Z
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.
Loop quantization of the Gowdy model with local rotational symmetry
de Blas, Daniel Martín; Paw?owski, Tomasz
2015-01-01T23:59:59.000Z
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.
Discrete Hamiltonian for General Relativity
Ziprick, Jonathan
2015-01-01T23:59:59.000Z
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
2015-07-27T23:59:59.000Z
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
2007-04-26T23:59:59.000Z
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}.
Joglekar, Yogesh N
2015-01-01T23:59:59.000Z
$\\mathcal{PT}$-symmetric systems, until now, have been characterized by a real, parity-symmetric, kinetic Hamiltonian and a non-Hermitian, balanced gain-loss potential. We present a new class of discrete models in which the tunneling Hamiltonian is not parity-symmetric, and yet the models have a nonzero $\\mathcal{PT}$-breaking threshold in presence of a pair of gain-loss impurities $\\pm i\\gamma$ located at reflection-symmetric sites. We uncover a hidden symmetry that is instrumental to the finite threshold strength. We show that such models have topological edge-states that remain robust in the $\\mathcal{PT}$-broken phase. Our predictions substantially broaden possible realizations of a $\\mathcal{PT}$ system, particularly in optical waveguide arrays or coupled microstructures, by eliminating the parity-symmetry constraint.
Adrian C. Ottewill; Peter Taylor
2012-05-24T23:59:59.000Z
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
2009-10-09T23:59:59.000Z
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.
Software is Discrete Mathematics University of Oklahoma
Page, Rex L.
, discrete mathematics, predicate logic, correctness proofs, formal methods, software engineering. 1Software is Discrete Mathematics Rex L Page University of Oklahoma School of Computer Science Descriptors D.2.4 [Software Engineering]: Software/Program Verification correctness proofs, formal methods
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
2011-12-02T23:59:59.000Z
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.
Left-right symmetric model with {mu}{r_reversible}{tau} symmetry
Gomez-Izquierdo, Juan Carlos; Perez-Lorenzana, Abdel [Departamento de Fisica, Centro de Investigacion y de Estudios Avanzados del I.P.N., Apdo. Post. 14-740, 07000 Mexico D.F. (Mexico)
2009-04-20T23:59:59.000Z
We present a Left-right symmetric model with a (Z{sub 2}){sup 3} discrete symmetry which realizes softly broken {mu}{r_reversible}{tau} symmetry, which is broken at tree level in the effective neutrino mass matrix by mass difference in the diagonal Dirac mass terms. Lepton mixings arise from Majorana mass matrix. We determined {theta}{sub 13}, and the deviation from maximal value of {theta}{sub ATM} in terms of the hierarchy scale, m{sub 3}, and a single free parameter, h{sub s}.
Spontaneously broken quark helicity symmetry
Dalley, Simon [Department of Physics, University of Wales Swansea, Singleton Park, Swansea SA2 8PP (United Kingdom); McCartor, Gary [Department of Physics, SMU Dallas, TX 75275 (United States)]. E-mail: mccartor@mail.physics.smu.edu
2006-02-15T23:59:59.000Z
We discuss the origin of chiral-symmetry breaking in the light-cone representation of QCD. In particular, we show how quark helicity symmetry is spontaneously broken in SU (N) gauge theory with massless quarks if that theory has a condensate of fermion light-cone zero modes. The symmetry breaking appears as induced interactions in an effective light-cone Hamiltonian equation based on a trivial vacuum. The induced interaction is crucial for generating a splitting between pseudoscalar and vector meson masses, which we illustrate with spectrum calculations in some 1 + 1-dimensional reduced models of gauge theory.
Negative Energy Solutions and Symmetries
Burra G. Sidharth
2011-04-01T23:59:59.000Z
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.
Crossovers between superconducting symmetry classes
V. A. Koziy; M. A. Skvortsov
2011-06-20T23:59:59.000Z
We study the average density of states in a small metallic grain coupled to two superconductors with the phase difference $\\pi$, in a magnetic field. The spectrum of the low-energy excitations in the grain is described by the random matrix theory whose symmetry depends on the magnetic field strength and coupling to the superconductors. In the limiting cases, a pure superconducting symmetry class is realized. For intermediate magnetic fields or couplings to the superconductors, the system experiences a crossover between different symmetry classes. With the help of the supersymmetric sigma-model we derive the exact expressions for the average density of states in the crossovers between the symmetry classes A-C and CI-C.
Domain wall solitons and Hopf algebraic translational symmetries in noncommutative field theories
Sasai, Yuya; Sasakura, Naoki [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)
2008-02-15T23:59:59.000Z
Domain wall solitons are the simplest topological objects in field theories. The conventional translational symmetry in a field theory is the generator of a one-parameter family of domain wall solutions, and induces a massless moduli field which propagates along a domain wall. We study similar issues in braided noncommutative field theories possessing Hopf algebraic translational symmetries. As a concrete example, we discuss a domain wall soliton in the scalar {phi}{sup 4} braided noncommutative field theory in Lie-algebraic noncommutative space-time, [x{sup i},x{sup j}]=2i{kappa}{epsilon}{sup ijk}x{sub k} (i,j,k=1,2,3), which has a Hopf algebraic translational symmetry. We first discuss the existence of a domain wall soliton in view of Derrick's theorem, and construct explicitly a one-parameter family of solutions in perturbation of the noncommutativity parameter {kappa}. We then find the massless moduli field which propagates on the domain wall soliton. We further extend our analysis to the general Hopf algebraic translational symmetry.
Classification of constraints and degrees of freedom for quadratic discrete actions
Philipp A. Hoehn
2014-11-13T23:59:59.000Z
We provide a comprehensive classification of constraints and degrees of freedom for variational discrete systems governed by quadratic actions. This classification is based on the different types of null vectors of the Lagrangian two-form and employs the canonical formalism developed in arXiv:1303.4294 [math-ph] (J. Math. Phys. 54, 093505 (2013)) and arXiv:1401.6062 [gr-qc] (J. Math. Phys. 55, 083508 (2014)). The analysis is carried out in both the classical and quantum theory and applies to systems with both temporally varying or constant discretization. In particular, it is shown explicitly how changes in the discretization, e.g. resulting from canonical coarse graining or refining operations or an evolving background geometry, change the dynamical content of the system. It is demonstrated how, on a temporally varying discretization, constraints, Dirac observables, symmetries, reduced phase spaces and physical Hilbert spaces become spacetime region dependent. These results are relevant for free field theory on an evolving lattice and linearized discrete gravity models.
Dual hidden landscapes in Anderson localization on discrete lattices
Marcelo Leite Lyra; Svitlana Mayboroda; Marcel Filoche
2014-10-09T23:59:59.000Z
The localization subregions of stationary waves in continuous disordered media have been recently demonstrated to be governed by a hidden landscape that is the solution of a Dirichlet problem expressed with the wave operator. In this theory, the strength of Anderson localization confinement is determined by this landscape, and continuously decreases as the energy increases. However, this picture has to be changed in discrete lattices in which the eigenmodes close to the edge of the first Brillouin zone are as localized as the low energy ones. Here we show that in a 1D discrete lattice, the localization of low and high energy modes is governed by two different landscapes, the high energy landscape being the solution of a dual Dirichlet problem deduced from the low energy one using the symmetries of the Hamiltonian. We illustrate this feature using the one-dimensional tight-binding Hamiltonian with random on-site potentials as a prototype model. Moreover we show that, besides unveiling the subregions of Anderson localization, these dual landscapes also provide an accurate overal estimate of the localization length over the energy spectrum, especially in the weak disorder regime.
Ely, Gregory
2013-01-01T23:59:59.000Z
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.
Yoon, Joon Sik, 1973-
2005-01-01T23:59:59.000Z
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 ...
Center symmetry and Hagedorn spectrum
Cohen, Thomas D
2015-01-01T23:59:59.000Z
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
2011-08-19T23:59:59.000Z
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.
Effective field theory for spacetime symmetry breaking
Yoshimasa Hidaka; Toshifumi Noumi; Gary Shiu
2014-12-17T23:59:59.000Z
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.
Sawa Manoff
2004-01-04T23:59:59.000Z
Doppler effect and Hubble effect in different models of space-time in the case of auto-parallel motion of the observer are considered. The Doppler effect and shift frequency parameter are specialized for the case of auto-parallel motion of the observer. The Hubble effect and shift frequency parameter are considered for the same case. It is shown that by the use of the variation of the shift frequency parameter during a time perod, considered locally in the proper frame of reference of an observer, one can directly determine the centrifugal (centripetal) relative velocity and acceleration as well as the Coriolis relative velocity and acceleration of an astronomical object moving relatively to the observer. All results are obtained on purely kinematic basis without taking into account the dynamic reasons for the considered effect. PACS numbers: 98.80.Jk; 98.62.Py; 04.90.+e; 04.80.Cc
Ayan Banerjee; Farook Rahaman; Kanti Jotania; Ranjan Sharma; Mosiur Rahaman
2014-12-05T23:59:59.000Z
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.
Exacting N=4 Superconformal Symmetry
Till Bargheer; Niklas Beisert; Wellington Galleas; Florian Loebbert; Tristan McLoughlin
2009-11-02T23:59:59.000Z
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
2009-01-01T23:59:59.000Z
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.
Quasicrystals with discrete support and spectrum
Nir Lev; Alexander Olevskii
2015-09-08T23:59:59.000Z
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.
(Small) Resonant non-Gaussianities: Signatures of a Discrete Shift Symmetry
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(Small) Resonant non-Gaussianities: Signatures of a Discrete Shift Symmetry
Office of Scientific and Technical Information (OSTI)
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(Small) resonant non-gaussianities: signatures of a discrete shift symmetry
Office of Scientific and Technical Information (OSTI)
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Reciprocal Symmetry and Classical Discrete Oscillator Incorporating Half-Integral Energy Levels
Mushfiq Ahmad
2007-04-02T23:59:59.000Z
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)
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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)
2014-07-23T23:59:59.000Z
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.
Symmetry breaking in laser cavities
Malomed, Boris A
2015-01-01T23:59:59.000Z
A brief introduction to the topic of spontaneous symmetry breaking (SSB) in conservative and dissipative nonlinear systems with an underlying double-well-potential structure is given. The reason is a discussion of a recent observation of the SSB a dual-core nanolaser cavity [5]. The effect is illustrated by means of a simple semi-analytically-tractable model (Fig. 1).
Testing Lorentz symmetry with atoms and Light
Neil Russell
2011-09-04T23:59:59.000Z
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.
Symmetry Breaking Revisited Jean-Francois Puget
Flener, Pierre
Symmetry Breaking Revisited Jean-Fran¸cois Puget ILOG, 9 avenue de Verdun, 94253 Gentilly, France, puget@ilog.fr Abstract. Symmetries in constraint satisfaction problems (CSPs) are one
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 ...
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
Ken-ichi Maruno; Gino Biondini
2005-04-09T23:59:59.000Z
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).
Twisted X-rays: incoming waveforms yielding discrete diffraction patterns for helical structures
Friesecke, Gero; Jüstel, Dominik
2015-01-01T23:59:59.000Z
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 ...
From Additional Symmetries to Linearization of Virasoro Symmetries
Chao-Zhong Wu
2011-12-01T23:59:59.000Z
We construct the additional symmetries and derive the Adler-Shiota-van Moerbeke formula for the two-component BKP hierarchy. We also show that the Drinfeld-Sokolov hierarchies of type D, which are reduced from the two-component BKP hierarchy, possess symmetries written as the action of a series of linear Virasoro operators on the tau function. It results in that the Drinfeld-Sokolov hierarchies of type D coincide with Dubrovin and Zhang's hierarchies associated to the Frobenius manifolds for Coxeter groups of type D, and that every solution of such a hierarchy together with the string equation is annihilated by certain combinations of the Virasoro operators and the time derivations of the hierarchy.
Andrei P. Kirilyuk
2014-05-14T23:59:59.000Z
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
2015-02-10T23:59:59.000Z
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.
Adjoint $SU(5)$ GUT model with $T_{7}$ flavor symmetry
Arbeláez, Carolina; Kovalenko, Sergey; Schmidt, Iván
2015-01-01T23:59:59.000Z
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...
Peccei-Quinn Symmetry from Dynamical Supersymmetry Breaking
Harigaya, Keisuke; Schmitz, Kai; Yanagida, Tsutomu T
2015-01-01T23:59:59.000Z
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
2015-05-27T23:59:59.000Z
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.
R B Burston
2007-08-14T23:59:59.000Z
We use the covariant and gauge-invariant 1+1+2 formalism of Clarkson and Barrett \\cite{Clarkson2003} to analyze electromagnetic (EM) perturbations on non-vacuum {\\it locally rotationally symmetric} (LRS) class II space-times. Ultimately, we show how to derive six real decoupled equations governing the total of six EM scalar and 2-vector harmonic amplitudes. Four of these are new, and result from expanding the complex EM 2-vector which we defined in \\cite{Burston2007} in terms of EM 2-vector harmonic amplitudes. We are then able to show that there are four precise combinations of the amplitudes that decouple, two of these are polar perturbations whereas the remaining two are axial. The remaining two decoupled equations are the generalized Regge-Wheeler equations which were developed previously in \\cite{Betschart2004}, and these govern the two EM scalar harmonic amplitudes. However, our analysis generalizes this by including a full description and classification of energy-momentum sources, such as charges and currents.
Anatomy of a deformed symmetry: Field quantization on curved momentum space
Arzano, Michele [Institute for Theoretical Physics, Utrecht University, Leuvenlaan 4, Utrecht 3584 CE (Netherlands)
2011-01-15T23:59:59.000Z
In certain scenarios of deformed relativistic symmetries relevant for noncommutative field theories particles exhibit a momentum space described by a non-Abelian group manifold. Starting with a formulation of phase space for such particles which allows for a generalization to include group-valued momenta we discuss quantization of the corresponding field theory. Focusing on the particular case of {kappa}-deformed phase space we construct the one-particle Hilbert space and show how curvature in momentum space leads to an ambiguity in the quantization procedure reminiscent of the ambiguities one finds when quantizing fields in curved space-times. The tools gathered in the discussion on quantization allow for a clear definition of the basic deformed field mode operators and two-point function for {kappa}-quantum fields.
Probabilistic Calibration of a Discrete Particle Model
Zhang, Yanbei
2011-10-21T23:59:59.000Z
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 ...
Xiaoning Wu
2006-06-06T23:59:59.000Z
In this paper, we consider the discrete AKNS-D hierarchy, find the construction of the hierarchy, prove the bilinear identity and give the construction of the $\\tau$-functions of this hierarchy.
Spatially Discrete FitzHugh-Nagumo Equations
Elmer, Christopher E.; Van Vleck, Erik
2005-04-05T23:59:59.000Z
We consider pulse and front solutions to a spatially discrete FitzHugh--Nagumo equation that contains terms to represent both depolarization and hyperpolarization of the nerve axon. We demonstrate a technique for deriving ...
Discrete element modelling of cementitious materials
Brown, Nicholas John
2013-07-01T23:59:59.000Z
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 ...
Thomas D. Cohen
2014-07-15T23:59:59.000Z
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
2006-04-27T23:59:59.000Z
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
2015-02-22T23:59:59.000Z
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
2013-06-12T23:59:59.000Z
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.
Symmetry and Dirac points in graphene spectrum
Gregory Berkolaiko; Andrew Comech
2015-04-23T23:59:59.000Z
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.
Dynamics-dependent symmetries in Newtonian mechanics
Peter Holland
2014-09-19T23:59:59.000Z
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.
Inflation, Symmetry, and B-Modes
Mark P. Hertzberg
2015-07-27T23:59:59.000Z
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.
QCD, Symmetry Breaking and the Random Lattice
Saul D. Cohen
2006-02-15T23:59:59.000Z
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.
1987-10-19T23:59:59.000Z
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.
Breaking Parity Symmetry Using Extra Dimensions
R. N. Mohapatra; A. Pérez-Lorenzana
1999-11-17T23:59:59.000Z
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.
Symmetries in Linear and Integer Programs
Bödi, R
2009-01-01T23:59:59.000Z
The notion of symmetry is defined in the context of Linear and Integer Programming. Symmetric linear and integer programs are studied from a group theoretical viewpoint. We show that for any linear program there exists an optimal solution in the fixed point set of its symmetry group. Using this result, we develop an algorithm that allows for reducing the dimension of any linear program having a non-trivial group of symmetries.
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)
1997-04-01T23:59:59.000Z
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
2015-01-07T23:59:59.000Z
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.
Superconformal symmetry, NMSSM, and inflation
Ferrara, Sergio [Physics Department, Theory Unit, CERN, CH 1211, Geneva 23 (Switzerland); INFN - Laboratori Nazionali di Frascati, Via Enrico Fermi 40, 00044 Frascati (Italy); Kallosh, Renata; Linde, Andrei; Marrani, Alessio [Department of Physics, Stanford University, Stanford, California 94305 (United States); Van Proeyen, Antoine [Instituut voor Theoretische Fysica, Katholieke Universiteit Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium)
2011-01-15T23:59:59.000Z
We identify a particularly simple class of supergravity models describing superconformal coupling of matter to supergravity. In these models, which we call the canonical superconformal supergravity models, the kinetic terms in the Jordan frame are canonical, and the scalar potential is the same as in the global theory. The pure supergravity part of the total action has a local Poincare supersymmetry, whereas the chiral and vector multiplets coupled to supergravity have a larger local superconformal symmetry. The scale-free globally supersymmetric theories, such as the NMSSM with a scale-invariant superpotential, can be naturally embedded into this class of theories. After the supergravity embedding, the Jordan frame scalar potential of such theories remains scale free; it is quartic, it contains no mass terms, no nonrenormalizable terms, no cosmological constant. The local superconformal symmetry can be broken by additional terms, which, in the small field limit, are suppressed by the gravitational coupling. This can be achieved by introducing the nonminimal scalar-curvature coupling, and by taking into account interactions with a hidden sector. In this approach, the smallness of the mass parameters in the NMSSM may be traced back to the original superconformal invariance. This allows one to address the {mu} problem and the cosmological domain wall problem in this model, and to implement chaotic inflation in the NMSSM. We discuss the gravitino problem in the NMSSM inflation, as well as the possibility to obtain a broad class of new versions of chaotic inflation in supergravity.
Contact Symmetries and Hamiltonian Thermodynamics
A. Bravetti; C. S. Lopez-Monsalvo; F. Nettel
2015-02-22T23:59:59.000Z
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 violation in several Lepton-Flavor-Violating processes
Vasquez, Juan Carlos
2015-01-01T23:59:59.000Z
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
2015-04-29T23:59:59.000Z
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.
Symmetry energy in nuclear density functional theory
W. Nazarewicz; P. -G. Reinhard; W. Satula; D. Vretenar
2013-07-22T23:59:59.000Z
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.
Symmetries and Renormalization of Noncommutative Field Theory
Szabo, Richard J. [Department of Mathematics, Heriot-Watt University, Colin Maclaurin Building, Riccarton, Edinburgh EH14 4AS (United Kingdom); Maxwell Institute for Mathematical Sciences, Heriot-Watt University, Colin Maclaurin Building, Riccarton, Edinburgh EH14 4AS (United Kingdom)
2007-06-19T23:59:59.000Z
An overview of recent developments in the renormalization and in the implementation of spacetime symmetries of noncommutative field theory is presented, and argued to be intimately related.
The shift-invariant discrete wavelet transform and application to ...
2005-03-29T23:59:59.000Z
scribe a newly developed simple and fast convolution algo- rithm for the ISIDWT, ... (z1 ,z2 ,...,zN), e.g., air pressure measured repeatedly at evenly spaced time ...
Symmetries in collective neutrino oscillations
Huaiyu Duan; George M. Fuller; Yong-Zhong Qian
2009-07-31T23:59:59.000Z
We discuss the relationship between a symmetry in the neutrino flavour evolution equations and neutrino flavour oscillations in the collective precession mode. This collective precession mode can give rise to spectral swaps (splits) when conditions can be approximated as homogeneous and isotropic. Multi-angle numerical simulations of supernova neutrino flavour transformation show that when this approximation breaks down, non-collective neutrino oscillation modes decohere kinematically, but the collective precession mode still is expected to stand out. We provide a criterion for significant flavour transformation to occur if neutrinos participate in a collective precession mode. This criterion can be used to understand the suppression of collective neutrino oscillations in anisotropic environments in the presence of a high matter density. This criterion is also useful in understanding the breakdown of the collective precession mode when neutrino densities are small.
Marius de Leeuw; Takuya Matsumoto; Sanefumi Moriyama; Vidas Regelskis; Alessandro Torrielli
2012-04-11T23:59:59.000Z
We discuss special quantum group (secret) symmetries of the integrable system associated to the AdS/CFT correspondence. These symmetries have by now been observed in a variety of forms, including the spectral problem, the boundary scattering problem, n-point amplitudes, the pure-spinor formulation and quantum affine deformations.
de Leeuw, Marius; Moriyama, Sanefumi; Regelskis, Vidas; Torrielli, Alessandro
2012-01-01T23:59:59.000Z
We discuss special quantum group (secret) symmetries of the integrable system associated to the AdS/CFT correspondence. These symmetries have by now been observed in a variety of forms, including the spectral problem, the boundary scattering problem, n-point amplitudes, the pure-spinor formulation and quantum affine deformations.
Symmetries in Nuclei P. Van Isacker
Boyer, Edmond
of symmetry and dynamical symmetry in quantum mechanics are introduced and illustrated with simple examples the nineteenth century and made another leap forward in 1873 when Sophus Lie proposed the concept of a Lie group of quantum mechanics, and it became clear that group theory provides a powerful tool to understand
On systems having Poincaré and Galileo symmetry
Peter Holland
2014-11-13T23:59:59.000Z
Using the wave equation in d > or = 1 space dimensions it is illustrated how dynamical equations may be simultaneously Poincar\\'e and Galileo covariant with respect to different sets of independent variables. This provides a method to obtain dynamics-dependent representations of the kinematical symmetries. When the field is a displacement function both symmetries have a physical interpretation. For d = 1 the Lorentz structure is utilized to reveal hitherto unnoticed features of the non-relativistic Chaplygin gas, including a relativistic structure with a limiting case that exhibits the Carroll group, and field-dependent symmetries and associated Noether charges. The Lorentz transformations of the potentials naturally associated with the Chaplygin system are given. These results prompt the search for further symmetries and it is shown that the Chaplygin equations support a nonlinear superposition principle. A known spacetime mixing symmetry is shown to decompose into label-time and superposition symmetries. It is shown that a quantum mechanical system in a stationary state behaves as a Chaplygin gas. The extension to d > 1 is used to illustrate how the physical significance of the dual symmetries is contingent on the context by showing that Maxwells equations exhibit an exact Galileo covariant formulation where Lorentz and gauge transformations are represented by field-dependent symmetries. A natural conceptual and formal framework is provided by the Lagrangian and Eulerian pictures of continuum mechanics.
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
Model Uncertainty in Discrete Event Stanley Young
Garg, Vijay
Abstract Earlier work concerning control of discrete event systems usually assumed that a correct model to test for the correct model or noti cation that the remaining models cannot be controllably distin- guished. We use the nite state machine model with controllable and uncontrollable events presented
Contributions to the development of residual discretizations
Paris-Sud XI, Université de
Contributions to the development of residual discretizations for hyperbolic conservation laws with application to shallow water flows Manuscript submitted in fulfillment of the requirements for the obtention;Contents 1 Overview 9 1.1 Residual schemes for hyperbolic conservation laws
Dynamic Discrete Power Control in Cellular Networks
Avrachenkov, Konstantin
1 Dynamic Discrete Power Control in Cellular Networks Eitan Altman, Konstantin Avrachenkov, Ishai. In each of the two frameworks, we consider both cooperative as well as non-cooperative power control. We utilization. It is, therefore, in the interests of the users to control their transmit powers levels so
Regularized Discrete Optimal Transport Sira Ferradans1
Boyer, Edmond
. Jean-Francois.Aujol@math.u-bordeaux1.fr Abstract. This article introduces a generalization of discrete in modified images. In this article, we propose a variational formalism to relax and regularize the transport dedicated linear solvers (transportation simplex) and combinatorial algorithms (such as the Hungarian
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 profile alignment via constrained information bottleneck
Chechik, Gal
Discrete profile alignment via constrained information bottleneck Sean O'Rourke seano@cs.ucsd.edu Abstract Amino acid profiles, which capture position-specific mutation prob- abilities, are a richer encoding of biological sequences than the in- dividual sequences themselves. However, profile comparisons
Discrete profile alignment via constrained information bottleneck
Chechik, Gal
Discrete profile alignment via constrained information bottleneck Sean O'Rourke # seano@cs.ucsd.edu Abstract Amino acid profiles, which capture positionÂspecific mutation probÂ abilities, are a richer encoding of biological sequences than the inÂ dividual sequences themselves. However, profile comparisons
Infinite-dimensional symmetry for wave equation with additional condition
Irina Yehorchenko; Alla Vorobyova
2009-10-13T23:59:59.000Z
Symmetries for wave equation with additional conditions are found. Some conditions yield infinite-dimensional symmetry algebra for the nonlinear equation. Ansatzes and solutions corresponding to the new symmetries were constructed.
Discretization and Algorithms for Strong Coupling in Computational Aeroelasticity
8 4.1 Flow discretization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 4.2 Structural discretization . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.3 Mimicing the energy.4 A bifurcation at M1 = 0:95 . . . . . . . . . . . . . . . . . . . . . . . . . . 22 6.5 Stability chart
Controller Synthesis of Discrete Linear Plants Using MATTEO SLANINA
Sankaranarayanan, Sriram
Controller Synthesis of Discrete Linear Plants Using Polyhedra MATTEO SLANINA Stanford University controllers for linear discrete systems with disturbances. Given a plant description and a safety We study techniques for synthesizing synchronous controllers for affine plants with disturbances
Defining Employee Perceptions of Discretion: When, Where, and How
Thompson, Rebecca Jean
2013-12-10T23:59:59.000Z
discretion: choice over when, where, and how one works. Second, the influence of these three forms of discretion on both work-related outcomes (job satisfaction, burnout, and turnover intentions) and nonwork-related outcomes (life satisfaction, work...
Hiroshi Miki; Hiroaki Goda; Satoshi Tsujimoto
2012-02-29T23:59:59.000Z
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.
Miki, Hiroshi; Tsujimoto, Satoshi
2011-01-01T23:59:59.000Z
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.
ERROR ESTIMATES FOR THE EULER DISCRETIZATION OF AN ...
2014-12-10T23:59:59.000Z
Optimal control, nonlinear systems, state constraints, Euler discretization, rate of ... convergence, provided with modern variational techniques, are also [25]; ...
Fractional Topological Phases and Broken Time-Reversal Symmetry...
Office of Scientific and Technical Information (OSTI)
Fractional Topological Phases and Broken Time-Reversal Symmetry in Strained Graphene Prev Next Title: Fractional Topological Phases and Broken Time-Reversal Symmetry in...
Growth Mode and Substrate Symmetry Dependent Strain in Epitaxial...
Office of Scientific and Technical Information (OSTI)
Journal Article: Growth Mode and Substrate Symmetry Dependent Strain in Epitaxial Graphene. Citation Details In-Document Search Title: Growth Mode and Substrate Symmetry Dependent...
Investigations into the Nature of Halogen Bonding Including Symmetry...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
into the Nature of Halogen Bonding Including Symmetry Adapted Perturbation Theory Analyses. Investigations into the Nature of Halogen Bonding Including Symmetry Adapted...
Cheng, Juan, E-mail: cheng_juan@iapcm.ac.cn [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Shu, Chi-Wang, E-mail: shu@dam.brown.edu [Division of Applied Mathematics, Brown University, Providence, RI 02912 (United States)
2014-09-01T23:59:59.000Z
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.
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
Emergent Quantum Mechanics and Emergent Symmetries
Gerard 't Hooft
2007-07-31T23:59:59.000Z
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.
Constraints on leptogenesis from a symmetry viewpoint
Gonzalez Felipe, R. [Area Cientifica de Fisica, Instituto Superior de Engenharia de Lisboa, Rua Conselheiro Emidio Navarro 1, 1959-007 Lisboa (Portugal); Departamento de Fisica and Centro de Fisica Teorica de Particulas (CFTP), Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Serodio, H. [Departamento de Fisica and Centro de Fisica Teorica de Particulas (CFTP), Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001 Lisboa (Portugal)
2010-03-01T23:59:59.000Z
It is shown that type I seesaw models based on the standard model Lagrangian extended with three heavy Majorana right-handed fields do not have leptogenesis in leading order, if the symmetries of mass matrices are also the residual symmetry of the Lagrangian. In particular, flavor models that lead to a mass-independent leptonic mixing have a vanishing leptogenesis CP asymmetry. Based on symmetry arguments, we prove that in these models the Dirac-neutrino Yukawa coupling combinations relevant for leptogenesis are diagonal in the physical basis where the charged leptons and heavy Majorana neutrinos are diagonal.
Constraints on leptogenesis from a symmetry viewpoint
R. Gonzalez Felipe; H. Serodio
2010-03-17T23:59:59.000Z
It is shown that type I seesaw models based on the standard model Lagrangian extended with three heavy Majorana right-handed fields do not have leptogenesis in leading order, if the symmetries of mass matrices are also the residual symmetry of the Lagrangian. In particular, flavor models that lead to a mass-independent leptonic mixing have a vanishing leptogenesis CP asymmetry. Based on symmetry arguments, we prove that in these models the Dirac-neutrino Yukawa coupling combinations relevant for leptogenesis are diagonal in the physical basis where the charged leptons and heavy Majorana neutrinos are diagonal.
Constraints on leptogenesis from a symmetry viewpoint
Felipe, R Gonzalez
2009-01-01T23:59:59.000Z
It is shown that type-I seesaw models based on the Standard Model Lagrangian extended with three heavy Majorana right-handed fields do not have leptogenesis in leading order, if the symmetries of mass matrices are also the residual symmetry of the Lagrangian. In particular, flavor models that lead to a mass-independent leptonic mixing have a vanishing leptogenesis CP-asymmetry. Based on symmetry arguments, we prove that in these models the Dirac-neutrino Yukawa coupling combinations relevant for leptogenesis are always real in the physical basis where the charged leptons and heavy Majorana neutrinos are diagonal.
Graphene, Lattice QFT and Symmetries
L. B Drissi; E. H Saidi; M. Bousmina
2011-03-07T23:59:59.000Z
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
Degeneracy and Discreteness in Cosmological Model Fitting
Teng, Huan-Yu; Hu, Huan-Chen; Zhang, Tong-Jie
2015-01-01T23:59:59.000Z
We explore the degeneracy and discreteness problems in the standard cosmological model ({\\Lambda}CDM). We use the Observational Hubble Data (OHD) and the type Ia supernova (SNe Ia) data to study this issue. In order to describe the discreteness in fitting of data, we define a factor G to test the influence from each single data point and analyze the goodness of G. Our results indicate that a higher absolute value of G shows a better capability of distinguishing models, which means the parameters are restricted into smaller confidence intervals with a larger figure of merit evaluation. Consequently, we claim that the factor G is an effective way in model differentiation when using different models to fit the observational data.
SUSY and symmetry nonrestoration at high temperature
Bajc, Borut [J. Stefan Institute, 1001 Ljubljana (Slovenia)
1999-07-15T23:59:59.000Z
The status of internal symmetry breaking at high temperature in super-symmetric models is shortly reviewed. This possibility could solve some well known cosmological problems, such as the domain wall, monopole and false vacuum problems.
Symmetry energy coefficients for asymmetric nuclear matter
Fábio L. Braghin
2003-12-16T23:59:59.000Z
Symmetry energy coefficients of asymmetric nuclear matter are investigated as the inverse of nuclear matter polarizabilities with two different approaches. Firstly a general calculation shows they may depend on the neutron-proton asymmetry itself. The choice of particular prescriptions for the density fluctuations lead to certain isospin (n-p asymmetry) dependences of the polarizabilities. Secondly, with Skyrme type interactions, the static limit of the dynamical polarizability is investigated corresponding to the inverse symmetry energy coefficient which assumes different values at different asymmetries (and densities and temperatures). The symmetry energy coefficient (in the isovector channel) is found to increase as n-p asymmetries increase. The spin symmetry energy coefficient is also briefly investigated.
Space and time from translation symmetry
Albert Schwarz
2009-05-16T23:59:59.000Z
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.
CLASSICAL FIELD THEORY WITH Z (3) SYMMETRY
Ruck, H.M.
2010-01-01T23:59:59.000Z
and H.M. Ruck, Quantum field theory Potts model, J. Math.in cyclic symmetry field theories, Nucl. Phys. B167 M.J.waves in nonlinear field theories, Phys. Rev. Lett. 32. R.
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
Broken symmetries and directed collective energy transport
S. Flach; Y. Zolotaryuk; A. E. Miroshnichenko; M. V. Fistul
2001-10-09T23:59:59.000Z
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.
Enhanced Coset Symmetries and Higher Derivative Corrections
Neil Lambert; Peter West
2006-08-17T23:59:59.000Z
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)
2011-10-01T23:59:59.000Z
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.
DISCRETE SYNCHRONIZATION UNDER THE HIERARCHICAL VIEW POINT CAMILLE POIGNARD
.Shechtman discovered the existence of a solid (an aluminium-manganese alloy) presenting a 5-fold symmetry in its
Scalar Field Theories with Polynomial Shift Symmetries
Tom Griffin; Kevin T. Grosvenor; Petr Horava; Ziqi Yan
2015-08-04T23:59:59.000Z
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. [Golder Associates, Redmond, VA (United States); Wadleigh, E. [Marathon Oil Co., Midland, TX (United States)
1997-08-01T23:59:59.000Z
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.
Discrete sine-Gordon dynamics on networks
Dutykh, Denys
2015-01-01T23:59:59.000Z
In this study we consider the sine-Gordon equation formulated on domains which are not locally homeomorphic to any subset of the Euclidean space. More precisely, we formulate the discrete dynamics on trees and graphs. Each edge is assumed to be a 1D uniform lattice with end points identified with graph vertices. A special treatment is needed at the junctions in order to couple 1D lattices into a global communicating network. Our approach is based on considering the local conservation properties. Some preliminary numerical results are shown on a simple graph containing four loops. These results show the performance of the scheme in non-trivial realistic conditions.
Bilinear control of discrete spectrum Schrödinger operators
Kais Ammari; Zied Ammari
2010-05-17T23:59:59.000Z
The bilinear control problem of the Schr\\"odinger equation $i\\frac{\\partial}{\\partial t}\\psi(t)$ $=(A+u(t) B)\\psi(t)$, where $u(t)$ is the control function, is investigated through topological irreducibility of the set $\\mathfrak{M}=\\{e^{-it (A+u B)}, u\\in \\mathbb{R}, t>0\\}$ of bounded operators. This allows to prove the approximate controllability of such systems when the uncontrolled Hamiltonian $A$ has a simple discrete spectrum and under an appropriate assumption on $B$.
Quantumness of discrete Hamiltonian cellular automata
Hans-Thomas Elze
2014-07-08T23:59:59.000Z
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.
SNAP:SN (Discrete Ordinates) Application Proxy
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:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5(Million Cubic Feet) Oregon (Including Vehicle Fuel) (Million CubicRefiners SwitchBenefits Â»DepartmentWastewaterSLIDESHOW:2003 SN CRACSNAP:SN (Discrete
Collective neutrino oscillations and spontaneous symmetry breaking
Duan, Huaiyu
2015-01-01T23:59:59.000Z
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...
Viable axion from gauged flavor symmetries
Berenstein, David; Perkins, Erik [Department of Physics, University of California, Santa Barbara, California 93106 (United States)
2010-11-15T23:59:59.000Z
We consider a string-inspired nonsupersymmetric extension of the standard model with gauged anomalous U(1) flavor symmetries. Consistency requires the Green-Schwarz (GS) mechanism to cancel mixed anomalies. The additional required scalars provide Stueckelberg masses for the Z{sup '} particles associated to the gauged flavor symmetry, so they decouple at low energies. Our models also include a complex scalar field {phi} to generate Froggatt-Nielsen mass terms for light particles, giving a partial solution to the fermion mass problem. A residual approximate (anomalous) global symmetry survives at low energies. The associated pseudo-Goldstone mode is the phase of the {phi} scalar field, and it becomes the dominant contribution to the physical axion. An effective field theory analysis that includes neutrino masses gives a prediction for the axion decay constant. We find a simple model where the axion decay constant is in the center of the allowed window.
Gaussian states and geometrically uniform symmetry
Gianfranco Cariolaro; Roberto Corvaja; Gianfranco Pierobon
2014-10-20T23:59:59.000Z
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.
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)
2006-04-15T23:59:59.000Z
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.
Discrete Event Simulation of Molecular Dynamics with Configurable Logic
Herbordt, Martin
: {jtmodel|herbordt}@bu.edu Abstract: Molecular dynamics simulation based on discrete event simulation (DMD. Herbordt Department of Electrical and Computer Engineering Boston University; Boston, MA 02215 EMail
Lowest-rank Solutions of Continuous and Discrete Lyapunov ...
2012-10-08T23:59:59.000Z
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
2012-10-09T23:59:59.000Z
Oct 9, 2012 ... Abstract: The low-rank solutions of continuous and discrete Lyapunov equations are of great importance but generally difficult to achieve in ...
Discretization schemes for diffusion operators on general meshes
Herbin, Raphaèle
: Navier Stokes equations Flow in porous media, Darcy equation. discretization of -div( u)) A can Supplementary constraint from the oil reservoir simulation community: cell centred schemes transport equations
Symmetry violations in nuclear and neutron $?$ decay
K. K. Vos; H. W. Wilschut; R. G. E. Timmermans
2015-09-14T23:59:59.000Z
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.
Symmetry transformations in Batalin-Vilkovisky formalism
Albert Schwarz
1993-10-19T23:59:59.000Z
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
2015-05-07T23:59:59.000Z
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
2015-05-14T23:59:59.000Z
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.
Generalised CP and $\\Delta (6n^2)$ Family Symmetry in Semi-Direct Models of Leptons
Ding, Gui-Jun; Neder, Thomas
2014-01-01T23:59:59.000Z
We perform a detailed analysis of $\\Delta (6n^2)$ family symmetry combined with a generalised CP symmetry in the lepton sector, breaking to different remnant symmetries $G_{\
ccsd00003868, Symmetry and interactivity in
interplay is about, before we enter into the more speci#12;c topic we have in mind here, namely symmetry in which computation is proof search. I am speaking here of the larger match between two kinds of wide proofs { interesting ones rely on various lemmas, sublem- mas, etc... {, checking them, or searching them
Noncommutative gauge theories and Lorentz symmetry
Banerjee, Rabin; Chakraborty, Biswajit; Kumar, Kuldeep [S.N. Bose National Centre for Basic Sciences, JD Block, Sector 3, Salt Lake, Kolkata 700098 (India)
2004-12-15T23:59:59.000Z
We explicitly derive, following a Noether-like approach, the criteria for preserving Poincare invariance in noncommutative gauge theories. Using these criteria we discuss the various spacetime symmetries in such theories. It is shown that, interpreted appropriately, Poincare invariance holds. The analysis is performed in both the commutative as well as noncommutative descriptions and a compatibility between the two is also established.
Symmetries and dynamics in constrained systems
Xavier Bekaert; Jeong-Hyuck Park
2009-04-03T23:59:59.000Z
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.
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
2011-01-19T23:59:59.000Z
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 in k-Symplectic Field Theories
Roman-Roy, Narciso [Departamento de Matematica Aplicada IV. Edificio C-3, Campus Norte UPC, C/Jordi Girona 1.08034 Barcelona (Spain); Salgado, Modesto; Vilarino, Silvia [Departamento de Xeometria e Topoloxia, Facultade de Matematicas, Universidade de Santiago de Compostela. 15782 Santiago de Compostela (Spain)
2008-06-25T23:59:59.000Z
k-symplectic geometry provides the simplest geometric framework for describing certain class of first-order classical field theories. Using this description we analyze different kinds of symmetries for the Hamiltonian and Lagrangian formalisms of these field theories, including the study of conservation laws associated to them and stating Noether's theorem.
Information storage capacity of discrete spin systems
Beni Yoshida
2012-12-24T23:59:59.000Z
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)
2005-10-01T23:59:59.000Z
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.
Gapped symmetry preserving surface state for the electron topological insulator
Wang, Chong
It is well known that the three-dimensional (3D) electronic topological insulator (TI) with charge-conservation and time-reversal symmetry cannot have a trivial insulating surface that preserves symmetry. It is often ...
Fiber-Base Duality and Global Symmetry Enhancement
Vladimir Mitev; Elli Pomoni; Masato Taki; Futoshi Yagi
2014-11-10T23:59:59.000Z
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.
Optimal Control for Holonomic and Nonholonomic Mechanical Systems with Symmetry
Marsden, Jerrold
Optimal Control for Holonomic and Nonholonomic Mechanical Systems with Symmetry and Lagrangian Nonholonomic Mechanical Systems with Symmetry . . . . . . . . . . . . . . . 5 3 Optimal Control and Lagrangian.3 Optimal Control of a Holonomic System on a Principal Bundle . . . . . . . . . . . . 13 4 Optimal Control
Observable to explore high density behaviour of symmetry energy
Aman D. Sood
2011-09-28T23:59:59.000Z
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.
University of Michigan and NBER "Identification of Discrete Choice
Presenter: Jeremy Fox University of Michigan and NBER "Identification of Discrete Choice Models;Identification of Discrete Choice Models for Bundles and Binary Games Jeremy T. Fox University of Michigan and NBER Natalia Lazzati University of Michigan March 2014 Abstract We study nonparametric identification
Model Transformation with Hierarchical Discrete-Event Control
Model Transformation with Hierarchical Discrete- Event Control Thomas Huining Feng Electrical permission. #12;Model Transformation with Hierarchical Discrete-Event Control by Huining Feng B.S. (Nanjing Date Date University of California, Berkeley Spring 2009 #12;Model Transformation with Hierarchical
Directed Control of Discrete Event Systems: Optimization Based Approach
Kumar, Ratnesh
Directed Control of Discrete Event Systems: Optimization Based Approach J. Huang and R. Kumar an optimal director. Keywords: Discrete event systems, optimal control, supervisory control, directed control sense for plants that are executor of controllable events. In this paper we develop an optimization
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
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
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
From Discrete Specifications to Hybrid Control1 Paulo Tabuada
Pappas, George J.
@seas.upenn.edu Abstract A great challenge for modern systems theory is the de- sign of controllers for continuous systems inside physical devices has resulted in great challenges for modern and future systems and control theory given a discrete- time controllable linear system and a discrete specifica- tion (in the form
Discrete Wavelet Diffusion for Image Denoising Kashif Rajpoot1
Rajpoot, Nasir
Discrete Wavelet Diffusion for Image Denoising Kashif Rajpoot1 , Nasir Rajpoot2 , J. Alison Noble1 to iterative wavelet shrinkage, but only for (1) MallatZhong dyadic wavelet transform and (2) Haar wavelet shrinkage in the standard discrete wavelet transform (DWT) domain. Two of the major advantages
A DISCRETE WAVELET ANALYSIS OF FREAK WAVES IN THE OCEAN
A DISCRETE WAVELET ANALYSIS OF FREAK WAVES IN THE OCEAN EN-BING LIN AND PAUL C. LIU Received 25 wavelet analysis on a freak wave. We demonstrate several applications of wavelets and discrete and continuous wavelet transforms on the study of a freak wave. A modeling setting for freak waves will also
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
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
A Discrete-Event Systems Approach to Modeling Dextrous Manipulation
Graham, Nick
A Discrete-Event Systems Approach to Modeling Dextrous Manipulation S. L. Ricker? N. Sarkar?y K-event systems. The applicability of discrete-event systems to the modeling of dextrous manipulation tasks of the manipulation task, resulting in control discontinuities. The need for tech- niques to facilitate a smooth
Discrete Applied Mathematics 85 (1998) 59-70 MATHEMATICS
Fomin, Fedor V.
1998-01-01T23:59:59.000Z
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
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
Nuclear symmetry energy at subnormal densities from measured nuclear masses
Min Liu; Ning Wang; Zhuxia Li; Fengshou Zhang
2010-11-17T23:59:59.000Z
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.
Quasi-Symmetries of Determinantal Point Processes
Alexander I. Bufetov
2014-09-06T23:59:59.000Z
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.
Symmetry and Relativity : From Classical Mechanics to Modern Particle Physics
Paris-Sud XI, Université de
Symmetry and Relativity : From Classical Mechanics to Modern Particle Physics Z.J. Ajaltouni to modern particle physics will be given and some open questions will be raised. Keywords: Symmetry that symmetry represents a methodology followed by Modern Physics in order to build coherent and successful
Napp, Nils
Majorana modes at their boundary; the modes are protected by time-reversal symmetry from acquiring, contains a pair of Majorana modes ,R L that propagate in op- posite directions. The aforementioned) with 1d = , [ ]T R L = , and we have used the conventional Dirac gamma matrices for the relativistic
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
1996-11-27T23:59:59.000Z
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.
Symmetry Algebra of IIB Superstring Scattering
Gordon Chalmers
2005-10-26T23:59:59.000Z
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.
Radiatively broken symmetries of nonhierarchical neutrinos
Amol Dighe; Srubabati Goswami; Probir Roy
2007-09-17T23:59:59.000Z
Symmetry-based ideas, such as the quark-lepton complementarity (QLC) principle and the tri-bimaximal mixing (TBM) scheme, have been proposed to explain the observed mixing pattern of neutrinos. We argue that such symmetry relations need to be imposed at a high scale $\\Lambda \\sim 10^{12}$ GeV characterizing the large masses of right-handed neutrinos required to implement the seesaw mechanism. For nonhierarchical neutrinos, renormalisation group evolution down to a laboratory energy scale $\\lambda \\sim 10^3$ GeV tends to radiatively break these symmetries at a significant level and spoil the mixing pattern predicted by them. However, for Majorana neutrinos, suitable constraints on the extra phases $\\alpha_{2,3}$ enable the retention of those high scale mixing patterns at laboratory energies. We examine this issue within the Minimal Supersymmetric Standard Model (MSSM) and demonstrate the fact posited above for two versions of QLC and two versions of TBM. The appropriate constraints are worked out for all these four cases. Specifically, a preference for $\\alpha_2 \\approx \\pi$ (i.e. $m_1 \\approx -m_2$) emerges in each case. We also show how a future accurate measurement of $\\theta_{13}$ may enable some discrimination among these four cases in spite of renormalization group evolution.
Conformal Scaling Gauge Symmetry and Inflationary Universe
Yue-Liang Wu
2004-02-23T23:59:59.000Z
Considering the conformal scaling gauge symmetry as a fundamental symmetry of nature in the presence of gravity, a scalar field is required and used to describe the scale behavior of universe. In order for the scalar field to be a physical field, a gauge field is necessary to be introduced. A gauge invariant potential action is constructed by adopting the scalar field and a real Wilson-like line element of the gauge field. Of particular, the conformal scaling gauge symmetry can be broken down explicitly via fixing gauge to match the Einstein-Hilbert action of gravity. As a nontrivial background field solution of pure gauge has a minimal energy in gauge interactions, the evolution of universe is then dominated at earlier time by the potential energy of background field characterized by a scalar field. Since the background field of pure gauge leads to an exponential potential model of a scalar field, the universe is driven by a power-law inflation with the scale factor $a(t) \\sim t^p$. The power-law index $p$ is determined by a basic gauge fixing parameter $g_F$ via $p = 16\\pi g_F^2[1 + 3/(4\\pi g_F^2) ]$. For the gauge fixing scale being the Planck mass, we are led to a predictive model with $g_F=1$ and $p\\simeq 62$.
Space Time Quantization and the Big Bang
B. G. Sidharth
1998-06-21T23:59:59.000Z
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.
Terazawa, Hidezumi
2013-01-01T23:59:59.000Z
Exotic forms of matter such as carbon nanofoams, hexalambdas and 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.
Space time and the passage of time
George F. R. Ellis; Rituparno Goswami
2012-08-26T23:59:59.000Z
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
2015-01-01T23:59:59.000Z
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
2015-08-30T23:59:59.000Z
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.
Symmetry and the thermodynamics of currents in open quantum systems
Daniel Manzano; Pablo I. Hurtado
2014-09-25T23:59:59.000Z
Symmetry is a powerful concept in physics, and its recent application to understand nonequilibrium behavior is providing deep insights and groundbreaking exact results. Here we show how to harness symmetry to control transport and statistics in open quantum systems. Such control is enabled by a first-order-type dynamic phase transition in current statistics and the associated coexistence of different transport channels (or nonequilibrium steady states) classified by symmetry. Microreversibility then ensues, via the Gallavotti-Cohen fluctuation theorem, a twin dynamic phase transition for rare current fluctuations. Interestingly, the symmetry present in the initial state is spontaneously broken at the fluctuating level, where the quantum system selects the symmetry sector that maximally facilitates a given fluctuation. We illustrate these results in a qubit network model motivated by the problem of coherent energy harvesting in photosynthetic complexes, and introduce the concept of a symmetry-controlled quantum thermal switch, suggesting symmetry-based design strategies for quantum devices with controllable transport properties.
Numerical detection of symmetry enriched topological phases with space group symmetry
Ling Wang; Andrew Essin; Michael Hermele; Olexei Motrunich
2015-01-26T23:59:59.000Z
Topologically ordered phases of matter, in particular so-called symmetry enriched topological (SET) phases, can exhibit quantum number fractionalization in the presence of global symmetry. In Z_2 topologically ordered states in two dimensions, fundamental translations T_x and T_y acting on anyons can either commute or anticommute. This property, crystal momentum fractionalization, can be seen in a periodicity of the excited-state spectrum in the Brillouin zone. We present a numerical method to detect the presence of this form of symmetry enrichment given a projected entangled pair state (PEPS); we study the minima of spectrum of correlation lengths of the transfer matrix for a cylinder. As a benchmark, we demonstrate our method using a modified toric code model with perturbation. An enhanced periodicity in momentum clearly reveals the anticommutation relation {T_x,T_y}=0$ for the corresponding quasiparticles in the system.
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
A piecewise linear finite element discretization of the diffusion equation
Bailey, Teresa S
2006-10-30T23:59:59.000Z
In this thesis, we discuss the development, implementation and testing of a piecewise linear (PWL) continuous Galerkin finite element method applied to the threedimensional diffusion equation. This discretization is particularly interesting because...
Resolution of grain scale interactions using the Discrete Element Method
Johnson, Scott M. (Scott Matthew), 1978-
2006-01-01T23:59:59.000Z
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, ...
Design of discrete-time filters for efficient implementation
Wei, Dennis
2011-01-01T23:59:59.000Z
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
2002-07-26T23:59:59.000Z
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.
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. ...
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
2015-02-01T23:59:59.000Z
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
Direct measurement of yield stress of discrete materials
S. H. Ebrahimnazhad Rahbari; J. Vollmer; S. Herminghaus; M. Brinkmann
2012-06-09T23:59:59.000Z
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.
Dynamics of Symmetry Breaking and Tachyonic Preheating
Felder, Gary; Garcia-Bellido, Juan; Greene, Patrick B.; Kofman, Lev; Linde, Andrei; Tkachev, Igor
2001-07-02T23:59:59.000Z
We reconsider the old problem of the dynamics of spontaneous symmetry breaking (SSB) using 3D lattice simulations. We develop a theory of tachyonic preheating, which occurs due to the spinodal instability of the scalar field. Tachyonic preheating is so efficient that SSB typically completes within a single oscillation as the field rolls towards the minimum of its effective potential. We show that, contrary to previous expectations, preheating in hybrid inflation is typically tachyonic. Our results may also be relevant for the theory of the formation of topological defects and of disoriented chiral condensates in heavy ion collisions.
Fundamental Symmetries of the Modified Anyonic Particle
Nejad, Salman Abarghouei; Monemzadeh, Majid
2015-01-01T23:59:59.000Z
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.
Noncommutative geometry and twisted conformal symmetry
Matlock, Peter [Institute of Mathematical Sciences, Chennai (India)
2005-06-15T23:59:59.000Z
The twist-deformed conformal algebra is constructed as a Hopf algebra with twisted coproduct. This allows for the definition of conformal symmetry in a noncommutative background geometry. The twisted coproduct is reviewed for the Poincare algebra and the construction is then extended to the full conformal algebra. The case of Moyal-type noncommutativity of the coordinates is considered. It is demonstrated that conformal invariance need not be viewed as incompatible with noncommutative geometry; the noncommutativity of the coordinates appears as a consequence of the twisting, as has been shown in the literature in the case of the twisted Poincare algebra.
Strengthened PT-symmetry with P $\
Miloslav Znojil
2006-01-09T23:59:59.000Z
Two alternative scenarios are shown possible in Quantum Mechanics working with non-Hermitian $PT-$symmetric form of observables. While, usually, people assume that $P$ is a self-adjoint indefinite metric in Hilbert space (and that their $P-$pseudo-Hermitian Hamiltonians $H$ possess the real spectra etc), we propose to relax the constraint $P=P^\\dagger$ as redundant. Non-Hermitian triplet of coupled square wells is chosen for illustration purposes. Its solutions are constructed and the observed degeneracy of their spectrum is attributed to the characteristic nontrivial symmetry $S={P}^{-1} {P}^\\dagger \
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
Spontaneous breaking of spatial symmetries in collective neutrino oscillations
Huaiyu Duan; Shashank Shalgar
2014-12-22T23:59:59.000Z
A dense neutrino medium can experience collective oscillations or self-induced flavor transformation through nonlinear neutrino-neutrino refraction. To make the problem of collective neutrino oscillations more tractable, all previous studies on this subject have assumed some spatial symmetry or symmetries in the neutrino medium (e.g., translation symmetries in the early universe and spherical symmetry in core-collapse supernovae). We point out that the collective oscillation modes studied in such models are very special. Using a simple toy model we show that spatial symmetries can be broken spontaneously in collective neutrino oscillations. We also show that the spatial-symmetry-breaking (SSB) modes of neutrino oscillations can exist for both neutrino mass hierarchies and even in the regimes where collective neutrino oscillations were previously thought to be suppressed. This finding calls for study of collective neutrino oscillations in multi-dimensional models.
Spontaneous breaking of spatial symmetries in collective neutrino oscillations
Duan, Huaiyu
2014-01-01T23:59:59.000Z
A dense neutrino medium can experience collective oscillations or self-induced flavor transformation through nonlinear neutrino-neutrino refraction. To make the problem of collective neutrino oscillations more tractable, all previous studies on this subject have assumed some spatial symmetry or symmetries in the neutrino medium (e.g., translation symmetries in the early universe and spherical symmetry in core-collapse supernovae). We point out that the collective oscillation modes studied in such models are very special. Using a simple toy model we show that spatial symmetries can be broken spontaneously in collective neutrino oscillations. We also show that the spatial-symmetry-breaking (SSB) modes of neutrino oscillations can exist for both neutrino mass hierarchies and even in the regimes where collective neutrino oscillations were previously thought to be suppressed. This finding calls for study of collective neutrino oscillations in multi-dimensional models.
Peccei-Quinn symmetry, dark matter, and neutrino mass
Ma, Ernest [Department of Physics and Astronomy, University of California, Riverside, California 92521 (United States)
2014-06-24T23:59:59.000Z
It is pointed out that a residual Z{sub 2} symmetry of the usual anomalous Peccei-Quinn U(1){sub PQ} symmetry (which solves the strong CP problem) may be used for an absolutely stable heavy dark-matter particle in addition to the long-lived axion. The same Z{sub 2} symmetry may also be used to generate radiative neutrino mass.
Lorentz symmetry breaking effects on relativistic EPR correlations
Belich, H; Bakke, K
2015-01-01T23:59:59.000Z
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.
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))
1992-08-01T23:59:59.000Z
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
2015-06-16T23:59:59.000Z
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.
On Flavor Symmetry in Lattice Quantum Chromodynamics
El Hassan Saidi
2012-03-27T23:59:59.000Z
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.
Testing Time Reversal Symmetry in Artificial Atoms
Frederico Brito; Francisco Rouxinol; M. D. LaHaye; Amir O. Caldeira
2014-06-27T23:59:59.000Z
Over the past several decades, a rich series of experiments has repeatedly verified the quantum nature of superconducting devices, leading some of these systems to be regarded as artificial atoms. In addition to their application in quantum information processing, these `atoms' provide a test bed for studying quantum mechanics in macroscopic limits. Regarding the last point, we present here a feasible protocol for directly testing time reversal symmetry in a superconducting artificial atom. Time reversal symmetry is a fundamental property of quantum mechanics and is expected to hold if the dynamics of the artificial atom strictly follow the Schroedinger equation. However, this property has yet to be tested in any macroscopic quantum system. The test we propose is based on the verification of the microreversibility principle, providing a viable approach to verify quantum work fluctuation theorems - an outstanding challenge in quantum statistical mechanics. For this, we outline a procedure that utilizes the microreversibility test in conjunction with numerical emulations of Gibbs ensembles to verify these theorems over a large temperature range.
Temperature dependence of symmetry energy of finite nuclei
J. N. De; S. K. Samaddar
2012-02-06T23:59:59.000Z
The temperature dependence of the symmetry energy and the symmetry free energy coefficients of atomic nuclei is investigated in a finite temperature Thomas-Fermi framework employing the subtraction procedure. A substantial decrement in the symmetry energy coefficient is obtained for finite systems,contrary to those seen for infinite nuclear matter at normal and somewhat subnormal densities. The effect of the coupling of the surface phonons to the nucleonic motion is also considered; this is found to decrease the symmetry energies somewhat at low temperatures.
Symmetries and exact solutions of the rotating shallow water equations
Alexander Chesnokov
2008-08-11T23:59:59.000Z
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)
1997-01-01T23:59:59.000Z
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 energy at subnuclear densities deduced from nuclear masses
Kazuhiro Oyamatsu; Kei Iida
2010-04-19T23:59:59.000Z
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.
Reply to 'Comment on 'Noncommutative gauge theories and Lorentz symmetry''
Banerjee, Rabin; Chakraborty, Biswajit; Kumar, Kuldeep [S. N. Bose National Centre for Basic Sciences, JD Block, Sector 3, Salt Lake, Kolkata 700098 (India); Department of Physics, Panjab University, Chandigarh 160014 (India)
2008-02-15T23:59:59.000Z
This is a reply to the preceding 'Comment on 'Noncommutative gauge theories and Lorentz symmetry'', Phys. Rev. D 77, 048701 (2008) by Alfredo Iorio.
Symmetry in RLT cuts for the quadratic assignment and standard ...
Etienne De Klerk
2012-01-02T23:59:59.000Z
Jan 2, 2012 ... Symmetry in RLT cuts for the quadratic assignment and standard quadratic ... Category 1: Linear, Cone and Semidefinite Programming.
Discrete solitons in self-defocusing systems with $\\mathcal{PT}$-symmetric defects
Chen, Zhiqiang; Chai, Jinglei; Zhang, Xiangyu; Li, Yongyao; Malomed, Boris A
2015-01-01T23:59:59.000Z
We construct families of discrete solitons (DSs) in an array of self-defocusing waveguides with an embedded $\\mathcal{PT}$ (parity-time)-symmetric dimer, which is represented by a pair of waveguides carrying mutually balanced gain and loss. Four types of states attached to the embedded defect are found, namely, staggered and unstaggered bright localized modes and gray or anti-gray DSs. Their existence and stability regions expand with the increase of the strength of the coupling between the dimer-forming sites. The existence of the gray and staggered bright DSs is qualitatively explained by dint of the continuum limit. All the gray and anti-gray DSs are stable (some of them are unstable if the dimer carries the nonlinear $\\mathcal{PT}$ symmetry, represented by balanced nonlinear gain and loss; in that case, the instability does not lead to a blowup, but rather creates oscillatory dynamical states). The boundary between the gray and anti-gray DSs is predicted in an approximate analytical form.
QCD evolution equations from conformal symmetry
V. M. Braun; A. N. Manashov
2014-08-28T23:59:59.000Z
QCD evolution equations in $\\text{MS}$-like schemes can be recovered from the same equations in a modified theory, QCD in non-integer $d=4-2\\epsilon$ dimensions, which enjoys exact scale and conformal invariance at the critical point. Restrictions imposed by the conformal symmetry of the modified theory allow one to obtain complete evolution kernels in integer (physical) dimensions at the given order of perturbation theory from the spectrum of anomalous dimensions added by the calculation of the special conformal anomaly at one order less. We use this technique to derive two-loop evolution equations for flavor-nonsinglet quark-antiquark light-ray operators that encode the scale dependence of generalized hadron parton distributions.
The Möbius Symmetry of Quantum Mechanics
Alon E. Faraggi; Marco Matone
2015-02-16T23:59:59.000Z
The equivalence postulate approach to quantum mechanics aims to formulate quantum mechanics from a fundamental geometrical principle. Underlying the formulation there exists a basic cocycle condition which is invariant under $D$--dimensional M\\"obius transformations with respect to the Euclidean or Minkowski metrics. The invariance under global M\\"obius transformations implies that spatial space is compact. Furthermore, it implies energy quantisation and undefinability of quantum trajectories without assuming any prior interpretation of the wave function. The approach may be viewed as conventional quantum mechanics with the caveat that spatial space is compact, as dictated by the M\\"obius symmetry, with the classical limit corresponding to the decompactification limit. Correspondingly, there exists a finite length scale in the formalism and consequently an intrinsic regularisation scheme. Evidence for the compactness of space may exist in the cosmic microwave background radiation.
Neutrino symmetries from high to low scales
Probir Roy
2007-06-18T23:59:59.000Z
Proposed symmetry relations, e.g., quark-lepton complementarity (QLC) or tribimaximal mixing (TBM), need to be imposed at a high scale $\\wedge \\sim 10^{12}$ GeV characterising the large masses of right-handed neutrinos required to implement the seesaw mechanism. RG evolution down to the laboratory scale $\\lambda \\sim 10^3$ GeV, generically prone to spoil these relations and their predicted neutrino mixing patterns, can be made to preserve them by appropriately constraining the Majorana phases $\\alpha_{2,3}$. This is explicitly demonstrated in the MSSM for two versions of QLC and two versions of TBM. A preference for $\\alpha_2 \\simeq \\pi$ (i.e. $m_1 \\simeq - m_2$) emerges in each case. Discrimination among the four cases is shown to be possible by future measurements of $\\theta_{13}$.
Electronic Properties and Hidden Symmetries of Graphene
L. B Drissi; E. H Saidi; M. Bousmina
2010-08-26T23:59:59.000Z
Using the relation between the structural and the electronic properties of honeycomb, we study the hidden SU(3) symmetry of the graphene monolayer and exhibit the link with its electronic properties. We show that the conservation law of incoming and outgoing electronic momenta at each site of graphene is solved in terms of SU(3) representations; and the Fourier waves {\\phi}(k_{x},k_{y}) of the hopping electron may be classified by SU(3) highest weight multiplets {\\phi}_{p,q}({\\xi}). It is also shown that the phases arctan((k_{y})/(k_{x})) of the waves are quantized as (((p+q))/((p-q)))sqrt(3) with p, q positive integers. Other features are also discussed.
Infrared modification of gravity from conformal symmetry
Gegenberg, Jack; Seahra, Sanjeev S
2015-01-01T23:59:59.000Z
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.
Quantum symmetry and photoreactivity of azabenzenes
Chesko, J.D.M.
1995-06-01T23:59:59.000Z
The fundamental processes associated with a photochemical reaction are described with reference to experimental properties of azabenzenes. Consideration of both excitation and relaxation processes led to presentation of the symmetry propagator, a unifying principle which maps system fluctuations (perturbations acting on an initial state) with dissipations (transitions to different states), thus directing the energy flow along competing reactive and nonreactive pathways. A coherent picture of relaxation processes including chemical reactions was constructed with the aid of spectroscopic data. Pyrazine (1,4 diazine) possesses vibronically active modes which provide an efficient mechanism for internal conversion to the first excited singlet state, where other promoting modes of the correct symmetry induce both intersystem crossing to the triplet manifold, isomerization through diaza-benzvalene, and chemical reactions through cycloreversion of dewar pyrazine to yield HCN plus an azete. At higher energies simple H atom loss and internal conversion become more predominant, leading to ring opening followed by elimination of methylene nitrile and ground state reaction products. Efficiency of chemical transformations as dissipation mechanisms versus competing fluorescence, phosphorescence and radiationless relaxation was mapped from near ultraviolet to far ultraviolet by photodissociation quantum yields into reaction channels characterized by molecular beam photofragment translational spectroscopy. A reaction path model for azabenzene photochemistry was presented and tested against experiment. Presence of undiscovered channels in other azabenzene systems was predicted and verified. The dominant process, HCN elimination, was resolved into three distinct channels. Both molecular and atomic hydrogen elimination was observed, the former with significant vibrational excitation. Small yields of isomerization products, acetylene and N2, were also observed.
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 Poincar´e in `The evolution of the laws', Derni`eres Pens´ees. Abstract The dynamics of time-dependent evolution towards symmetry
Symmetry Remnants in the Face of Competing Interactions in Nuclei
Leviatan, A
2015-01-01T23:59:59.000Z
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.
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
Nonequilibrium symmetry breaking and pattern formation in magnetic films
Deutsch, Josh
films. Â p. 7/6 #12;Applications of Ferromagnetism Doodle Pads Refrigerator Magnets NonequilibriumNonequilibrium symmetry breaking and pattern formation in magnetic films Josh Deutsch University of California Santa Cruz Nonequilibrium symmetry breaking and pattern formation in magnetic films. Â p. 1/6 #12
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
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 breaking and low energy conformational fluctuations in
Drabold, David
Symmetry breaking and low energy conformational fluctuations in amorphous graphene Y. Li and D. A. Drabold* Department of Physics and Astronomy, Condensed Matter Surface Science Program, Ohio University Published online 21 December 2012 Keywords amorphous graphene, low-energy excitation, symmetry breaking
The Nuclear Symmetry Energy in Heavy Ion Collisions
Wolter, Hermann
2015-01-01T23:59:59.000Z
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
2015-06-15T23:59:59.000Z
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.
Discrete Cosmological Self-Similarity And Delta Scuti Stars
R. L. Oldershaw
2008-10-08T23:59:59.000Z
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.
Computer aided analysis and synthesis for discrete robust control systems
Setijawan, Bambang
1994-01-01T23:59:59.000Z
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...
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
2013-02-01T23:59:59.000Z
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
2015-07-14T23:59:59.000Z
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 [Universität Bonn; Chang, Emanuel [University of Washington; Savage, Martin [University of Washington; Lin, Huey-Wen [University of Washington; Orginos, Konstantinos [College of William and Mary, JLAB; Cohen, Saul [University of Washington; Detmold, William [MIT; Luu, Tom [College of William and Mary; Parreno, Assumpta [Universitat de Barcelona, Martí i Franquès 1; Junnarkar, Parikshit [University of New Hampshire; Walker-Loud, Andre Paul [LBNL, UC-Berkeley
2013-08-01T23:59:59.000Z
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}.
J. Piekarewicz
2014-10-14T23:59:59.000Z
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.
Error Exponent for Discrete Memoryless Multiple-Access Channels
Anastasopoulos, Achilleas
Error Exponent for Discrete Memoryless Multiple-Access Channels by Ali Nazari A dissertation Bayraktar Associate Professor Jussi Keppo #12;c Ali Nazari 2011 All Rights Reserved #12;To my parents. ii Becky Turanski, Nancy Goings, Michele Feldkamp, Ann Pace, Karen Liska and Beth Lawson for efficiently
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
Continuum Representation for Simulating Discrete Events of Battery Operation
Panchagnula, Mahesh
the discrete events in the cycling studies of lithium-ion batteries as a continuum event has been proposed-order pseudo-two-dimensional lithium-ion battery model that has several coupled and nonlinear partial that are currently fol- lowed for the modeling of charge/discharge cycles of lithium-ion batteries involve different
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
Double-distribution-function discrete Boltzmann model for combustion
Chuandong Lin; Aiguo Xu; Guangcai Zhang; Yingjun Li
2015-06-21T23:59:59.000Z
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 AND CONTINUOUS Website: http://AIMsciences.org DYNAMICAL SYSTEMS
Shiau, LieJune
well known fact: When there is dry friction, the force necessary to put the system into motion. 806Â815 OPERATOR SPLITTING METHOD FOR FRICTION CONSTRAINED DYNAMICAL SYSTEMS LieJune Shiau Department-discretization of those relations mod- eling a class of dynamical systems with friction was discussed. The main goal
Cryptanalyzing a discrete-time chaos synchronization secure communication system
Gonzalo Alvarez; Fausto Montoya; Miguel Romera; Gerardo Pastor
2003-11-21T23:59:59.000Z
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.
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
Multivariable Discrete Time Repetitive Control System Hammoud Saari1
Boyer, Edmond
Multivariable Discrete Time Repetitive Control System Hammoud Saari1 and Bernard Caron2 1 SETRAM, France hammoud.saari@yahoo.fr, bernard.caron@univ-savoie.fr Keywords: Repetitive Control, Multivariable), Ahn et al. (2007) and Saari et al. (2010)). Most of their works were focused on the problem
The Discrete Wavelet Transform and Wavelet Synopses Minos Garofalakis
Garofalakis, Minos
The Discrete Wavelet Transform and Wavelet Synopses Minos Garofalakis Technical University of Crete minos@acm.org SYNONYMS None. DEFINITION Wavelets are a useful mathematical tool for hierarchically decomposing functions in ways that are both efficient and theoretically sound. Broadly speaking, the wavelet
Spectral discretization of Darcy's equations with pressure dependent porosity
Paris-Sud XI, Université de
Spectral discretization of Darcy's equations with pressure dependent porosity by Mejdi Aza¨iez1 and the pressure p of the fluid. This system is an extension of Darcy's equations, which model the flow of the resulting system of equations which takes into account the axisymmetry of the domain and of the flow. We
Mortar spectral element discretization of Darcy's equations in nonhomogeneous medium
Paris-Sud XI, Université de
Mortar spectral element discretization of Darcy's equations in nonhomogeneous medium Mouna Daadaa Cedex 05 France. daadaa@ann.jussieu.fr 4 mai 2010 Abstract : We consider Darcy's equations. They turn out to be in good coherency with the theoretical results. R´esum´e : Les ´equations de Darcy mod