Jia, L Y
2016-01-01
The particle-hole symmetry (equivalence) of the full shell-model Hilbert space is straightforward and routinely used in practical calculations. In this work we show that this symmetry is preserved in the subspace truncated at a certain generalized seniority, and give the explicit transformation between the states in the two types (particle and hole) of representations. Based on the results, we study the particle-hole symmetry in popular theories that could be regarded as further truncations on top of the generalized seniority, including the microscopic interacting boson (fermion) model, the nucleon-pair approximation, and others.
Energy Level Statistics of SO(5) Limit of Super-symmetry U(6/4) in Interacting Boson-Fermion Model
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
We study the energy level statistics of the SO(5) limit of super-symmetry U(6/4) in odd-A nucleus using the interacting boson-fermion model. The nearest neighbor spacing distribution (NSD) and the spectral rigidity (△3)are investigated, and the factors that affect the properties of level statistics are also discussed. The results show that the boson number N is a dominant factor. If N is small, both the interaction strengths of subgroups SOB(5) and SOBF(5)and the spin play important roles in the energy level statistics, however, along with the increase of N, the statistics distribution would tend to be in Poisson form.
Tsekov, R
2016-01-01
Thermodynamically, bosons and fermions differ by their statistics only. A general entropy functional is proposed by superposition of entropic terms, typical for different quantum gases. The statistical properties of the corresponding Janus particles are derived by variation of the weight of the boson/fermion fraction. It is shown that di-bosons and anti-fermions separate in gas and liquid phases, while three-phase equilibrium appears for poly-boson/fermion Janus particles.
Inertial parameters in the interacting boson fermion approximation
International Nuclear Information System (INIS)
The Hartree-Bose-Fermi and the adiabatic approximations are used to derive analytic formulas for the moment of inertia and the decoupling parameter of the interacting boson fermion approximation for deformed systems. These formulas are applied to the SU(3) dynamical symmetry, obtaining perfect agreement with the exact results. (Authors)
SU(8) family unification with boson-fermion balance
CERN. Geneva
2014-01-01
Grand unification has been intensively investigated for over forty years, and many different approaches have been tried. In this talk I propose a model that involves three ingredients that do not appear in the usual constructions: (1) boson--fermion balance without full supersymmetry, (2) canceling the spin 1/2 fermion gauge anomalies against the anomaly from a gauged spin 3/2 gravitino, and (3) using a scalar field representation with non-zero U(1) generator to break the SU(8) gauge symmetry through a ground state which, before dynamical symmetry breaking, has a periodic U(1) generator structure. The model has a number of promising features: (1) natural incorporation of three families, (2) incorporation of the experimentally viable flipped SU(5) model, (3) a symmetry breaking pathway to the standard model using the scalar field required by boson-fermion balance, together with a stage of most attractive channel dynamical symmetry breaking, without postulating additional Higgs fields, (4) vanishing of bare Yuk...
Plethystic Vertex Operators and Boson-Fermion Correspondences
Fauser, Bertfried; King, Ronald C
2016-01-01
We study the algebraic properties of plethystic vertex operators, introduced in J. Phys. A: Math. Theor. 43 405202 (2010), underlying the structure of symmetric functions associated with certain generalized universal character rings of subgroups of the general linear group, defined to stabilize tensors of Young symmetry type characterized by a partition of arbitrary shape \\pi. Here we establish an extension of the well-known boson-fermion correspondence involving Schur functions and their associated (Bernstein) vertex operators: for each \\pi, the modes generated by the plethystic vertex operators and their suitably constructed duals, satisfy the anticommutation relations of a complex Clifford algebra. The combinatorial manipulations underlying the results involve exchange identities exploiting the Hopf-algebraic structure of certain symmetric function series and their plethysms.
Massive Boson-Fermion Degeneracy and the Early Structure of the Universe
Kounnas, Costas
2008-01-01
The existence of a new kind of massive boson-fermion symmetry is shown explicitly in the framework of the heterotic, type II and type II orientifold superstring theories. The target space-time is two-dimensional. Higher dimensional models are defined via large marginal deformations of JxJ-type. The spectrum of the initial undeformed two dimensional vacuum consists of massless boson degrees of freedom, while all massive boson and fermion degrees of freedom exhibit a new Massive Spectrum Degene...
SU(8) unification with boson-fermion balance
Adler, Stephen L
2014-01-01
We formulate an $SU(8)$ unification model motivated by requiring that the theory should incorporate the graviton, gravitinos, and the fermions and gauge fields of the standard model, with boson--fermion balance. Gauge field $SU(8)$ anomalies cancel between the gravitinos and spin $\\frac {1}{2}$ fermions. The 56 of scalars breaks $SU(8)$ to $SU(3)_{family} \\times SU(5)/Z_5$, with the fermion representation content needed for ``flipped'' $SU(5)$, and with the residual scalars in the representations needed for further gauge symmetry breaking to the standard model. Yukawa couplings of the 56 scalars to the fermions are forbidden by chiral and gauge symmetries. In the limit of vanishing gauge coupling, there are $N=1$ and $N=8$ supersymmetries relating the scalars to the fermions, which restrict the form of scalar self-couplings and should improve the convergence of perturbation theory, if not making the theory finite and ``calculable''. In an Appendix we give an analysis of symmetry breaking by a Higgs component,...
Boson-fermion duality in SU(m|n) supersymmetric Haldane-Shastry spin chain
International Nuclear Information System (INIS)
By using the Y(gl(m|n)) super Yangian symmetry of the SU(m|n) supersymmetric Haldane-Shastry spin chain, we show that the partition function of this model satisfies a duality relation under the exchange of bosonic and fermionic spin degrees of freedom. As a byproduct of this study of the duality relation, we find a novel combinatorial formula for the super Schur polynomials associated with some irreducible representations of the Y(gl(m|n)) Yangian algebra. Finally, we reveal an intimate connection between the global SU(m|n) symmetry of a spin chain and the boson-fermion duality relation
A new boson-fermion model of superconductivity
De Cao, Tian
2010-01-01
It is shown that the superconducting energy gap necessarily lead to the disappearance of some quasi-electrons, thus we suggest a new boson-fermion Hamiltonian to describe superconductivity. The new supercurrent equations are derived with this Hamiltonian. Some new results can be found besides the zero resistance effect, the Meissner effect and the magnetic flux quantum can be explained.
Reciprocal Symmetric Boltzmann Function and Unified Boson-Fermion Statistics
Ahmad, Mushfiq; Talukder, Muhammad O. G.
2007-01-01
The differential equation for Boltzmann's function is replaced by the corresponding discrete finite difference equation. The difference equation is, then, symmetrized so that the equation remains invariant when step d is replaced by -d. The solutions of this equation come in Boson-Fermion pairs. Reciprocal symmetric Boltzmann's function, thus, unifies both Bosonic and Fermionic distributions.
Functional Integrals and Collective Excitations in Boson-Fermion Model
Institute of Scientific and Technical Information of China (English)
YAN Jun
2006-01-01
In this paper, collective excitations in the boson-fermion model are investigated by means of functional integration method. The equations of energy gap and excitation spectrum are derived. Moreover, the Bose energy spectrum of zero wave vector Fermi fields is also calculated.
Twisted vertex algebras, bicharacter construction and boson-fermion correspondences
International Nuclear Information System (INIS)
The boson-fermion correspondences are an important phenomena on the intersection of several areas in mathematical physics: representation theory, vertex algebras and conformal field theory, integrable systems, number theory, cohomology. Two such correspondences are well known: the types A and B (and their super extensions). As a main result of this paper we present a new boson-fermion correspondence of type D-A. Further, we define a new concept of twisted vertex algebra of order N, which generalizes super vertex algebra. We develop the bicharacter construction which we use for constructing classes of examples of twisted vertex algebras, as well as for deriving formulas for the operator product expansions, analytic continuations, and normal ordered products. By using the underlying Hopf algebra structure we prove general bicharacter formulas for the vacuum expectation values for two important groups of examples. We show that the correspondences of types B, C, and D-A are isomorphisms of twisted vertex algebras
Boson-fermion mapping and dynamical supersymmetry in fermion models
Navratil, P.; Geyer, H. B.; Dobaczewski, J.
1996-01-01
We show that a dynamical supersymmetry can appear in a purely fermionic system. This ``supersymmetry without bosons" is constructed by application of a recently introduced boson-fermion Dyson mapping from a fermion space to a space comprised of collective bosons and ideal fermions. In some algebraic fermion models of nuclear structure, particular Hamiltonians may lead to collective spectra of even and odd nuclei that can be unified using the dynamical supersymmetry concept with Pauli correlat...
Coriolis coupling in the interacting boson fermion model
International Nuclear Information System (INIS)
The properties of a boson core coupled to a single-j particle are examined in the framework of the SU(3) limit of the interacting boson fermion model. It is shown that the Coriolis interaction arises in a natural way in this model. Excitation energies are calculated in the large boson number approximation. The analogy to the particle plus rotor model is discussed. (orig.)
International Nuclear Information System (INIS)
It is shown that in a particular basis the dynamical interaction of IBFM for a boson core coupled to a single-j particle in the SU(3) limit takes a tridiagonal form, as does the Coriolis interaction. Interference between this Coriolis-like effect in the boson-fermion dynamical interaction and the genuine Coriolis effect results in interesting features of IBFM: For a particular ratio of the interaction strength, depending only on the angular momentum of the odd particle, the K=j band exactly follows the rotational energy rule, is completely uncoupled from the other bands and has exactly the same moment of inertia as a ground-state band of the core. A possible interpretation of this feature in terms of spectrum-generating supersymmetry is suggested. (orig.)
The Littlewood-Richardson rule and the boson-fermion correspondence
International Nuclear Information System (INIS)
The boson-fermion correspondence is applied to derive explicit formulae for expressing the product of S-functions in terms of sums of S-functions associated to non-standard partitions. (author). Letter-to-the-editor
The structure of 193Au within the Interacting Boson Fermion Model
International Nuclear Information System (INIS)
A γγ angular correlation experiment investigating the nucleus 193Au is presented. In this work the level scheme of 193Au is extended by new level information on spins, multipolarities and newly observed states. The new results are compared with theoretical predictions from a general Interacting Boson Fermion Model (IBFM) calculation for the positive-parity states. The experimental data is in good agreement with an IBFM calculation using all proton orbitals between the shell closures at Z=50 and Z=126. As a dominant contribution of the d3/2 orbital to the wave function of the lowest excited states is observed, a truncated model of the IBFM using a Bose–Fermi symmetry is applied to the describe 193Au. Using the parameters of a fit performed for 193Au, the level scheme of 192Pt, the supersymmetric partner of 193Au, is predicted but shows a too small boson seniority splitting. We obtained a common fit by including states observed in 192Pt. With the new parameters a supersymmetric description of both nuclei is established
Interplay between single-particle and collective features in the boson fermion model
International Nuclear Information System (INIS)
We study the interplay between the single-particle and fermion-pair features in the boson fermion model, both above and below the transition temperature Tc, using the flow equation method. Upon lowering the temperature the single-particle fermionic spectral function (a) gradually develops a depletion of the low-energy states (pseudogap) for T*>T>Tc and a true superconducting gap for Tc and (b) exhibits a considerable transfer of spectral weight between the incoherent background and the narrow coherent peak(s) signifying long-lived quasiparticle features. The Cooperon spectral function consists of a δ-function peak, centered at the renormalized boson energy ω=E-tildeq and a surrounding incoherent background which is spread over a wide energy range. When the temperature approaches Tc from above, this peak for q=0 moves to ω=0, so that the static pair susceptibility diverges (Thouless criterion for the broken symmetry phase transition). Upon decreasing the temperature below Tc the Cooperon peak becomes the collective (Goldstone) mode Eq∝ vertical bar q vertical bar in the small-momentum region and simultaneously splits off from the incoherent background states which are expelled to the high-energy sector vertical bar ω vertical bar ≥2Δsc(T). We discuss the smooth evolution of these features upon approaching Tc from above and consider its feedback on the single-particle spectrum where a gradual formation of damped Bogoliubov modes (above Tc) is observed
The Binding Energy, Spin-Excitation Gap, and Charged Gap in the Boson-Fermion Model
Institute of Scientific and Technical Information of China (English)
YANG Kai-Hua; TIAN Guang-Shan; HAN Ru-Qi
2003-01-01
In this paper, by applying a simplified version of Lieb 's spin-refleetion-positivity method, which was recentlydeveloped by one of us [G.S. Tian and J.G. Wang, J. Phys. A: Math. Gen. 35 (2002) 941], we investigate some generalproperties of the boson-fermion Hamiltonian, which has been widely used as a phenomenological model to describe thereal-space pairing of electrons. On a mathematically rigorous basis, we prove that for either negative or positive couplingV, which represents the spontaneous decay and recombination process between boson and fermion in the model, thepairing energy of electrons is nonzero. Furthermore, we also show that the spin-excitation gap of the boson-fermionHamiltonian is always larger than its charged gap, as predicted by the pre-paired electron theory.
Wess-Zumino Model on Bosonic-Fermionic Noncommutative Superspace
Wang, Xu-Dong
2016-01-01
In our previous paper we construct a renormalizable Wess-Zumino action on BFNC superspace at the second order approximation of noncommutative parameters. The action contains about 200 terms which are necessary for renormalization. By removing chiral covariant derivatives and chiral coordinates we found that the BFNC Wess-Zumino action can be transformed to a simpler form which have manifest 1/2 supersymmetry. Based on this discovery, we can extend the BFNC Wess-Zumino action to the all order of noncommutative parameters. At first we introduce global symmetries, then obtain divergent operators in the effective action by using dimensional analysis, the next step is to construct all possible BFNC parameters, at the end we combine the BFNC parameters with the divergent operators. We present the explicit action up to the fourth order of noncommutative parameters. Because the action contain all possible divergent operators, it is renormalizable to all order in perturbative theory.
High-Temperature Atomic Superfluidity in Lattice Boson-Fermion Mixtures
Illuminati, F.; Albus, A
2003-01-01
We consider atomic Bose-Fermi mixtures in optical lattices and study the superfluidity of fermionic atoms due to s-wave pairing induced by boson-fermion interactions. We prove that the induced fermion-fermion coupling is always {\\it attractive} if the boson-boson on site interaction is repulsive, and predict the existence of an enhanced BEC--BCS crossover as the strength of the lattice potential is varied. We show that for direct on-site fermion-fermion {\\it repulsion}, the induced attraction...
Functional integrals and 1/h expansion in the boson-fermion model
Yan, Jun
2016-06-01
The effective action of boson-fermion model is derived by means of the functional integrals method and Popov-Faddeev canonical transformations. The energy gap equation and excitation spectrum equation are obtained from first order and second order perturbation expansions of functional determinant. In the long wave approximation, some analytical expressions of excitation spectrum are calculated by using the 1/h expansion technique, the results showed that analytical calculation is in good agreement with the numerical calculation. Moreover, the Nambu sum rules of Higgs bosons are analyzed and discussed.
Institute of Scientific and Technical Information of China (English)
YANG Jin; YU Wan-Lun; XIANG An-Ping
2006-01-01
We use Lewis-Riesenfeld invariant approach to treat the modified Jaynes-Cummings models involving any forms of nonlinearty of the bosonic field when strong boson-fermion couplings are nilpotent Grassmann valued. The general state functions, time evolution operator and the time-evolution expressions for both the bosonic number and the fermionic number are presented.
Level Density In Interacting Boson-Fermion-Fermion Model (IBFFM) Of The Odd-Odd Nucleus 196Au
International Nuclear Information System (INIS)
The level density of the odd-odd nucleus 196Au is investigated in the interacting boson-fermion-fermion model (IBFFM) which accounts for collectivity and complex interaction between quasiparticle and collective modes.The IBFFM total level density is fitted by Gaussian and its tail is also fitted by Bethe formula and constant temperature Fermi gas model
Deformed boson-fermion correspondence, Q-bosons, and topological strings on the conifold
Sulkowski, Piotr
2008-01-01
We consider two different physical systems for which the basis of the Hilbert space can be parametrized by Young diagrams: free complex fermions and the phase model of strongly correlated bosons. Both systems have natural deformations parametrized by a parameter Q: the former one is related to the deformed boson-fermion correspondence introduced by N. Jing, while the latter is the so-called Q-boson, arising also in the context of quantum groups. We show that both deformations are equivalent and can be realized in the same way in the algebra of Hall-Littlewood symmetric functions. Without a deformation, these reduce to Schur functions, which can be used to construct a generating function of plane partitions, reproducing a topological string partition function on $C^3$. A deformation of both systems leads then to a deformed generating function, which reproduces topological string partition function of the conifold, with the deformation parameter Q identified with the size of $P^1$.
Spin-dependent level density in interacting Boson-Fermion-Fermion model of the Odd-Odd Nucleus 196Au
International Nuclear Information System (INIS)
The level density of the odd-odd nucleus 196Au is investigated in the interacting boson-fermion-fermion model (IBFFM) which accounts for collectivity and complex interaction between quasiparticle and collective modes.The IBFFM spin-dependent level densities show high-spin reduction with respect to Bethe formula.This can be well accounted for by a modified spin-dependent level density formula. (authors)
β -decay rates of Cs-131121 in the microscopic interacting boson-fermion model
Mardones, E.; Barea, J.; Alonso, C. E.; Arias, J. M.
2016-03-01
β -decay rates of Cs-131121 have been calculated in the framework of the neutron-proton interacting boson-fermion model (IBFM-2). For odd-A nuclei, the decay operator can be written in a relatively simple form in terms of the one-nucleon transfer operator. Previous studies of β decay in IBFM-2 were based on a transfer operator obtained by using the number operator approximation (NOA). In this work a new form of the one-nucleon transfer operator, derived microscopically without the NOA approximation, is used. The results from both approaches are compared and show that the deviation from experimental data is reduced without using the NOA approximation. Indications about the renormalization of the Fermi and Gamow-Teller matrix elements are discussed. This is a further step toward a more complete description of low-lying states in medium and heavy nuclei which is necessary to compute reliable matrix elements in studies of current active interest such as double-β decay or neutrino absorption experiments.
A numerical algorithm for modelling boson-fermion stars in dilatonic gravity
International Nuclear Information System (INIS)
We investigate numerically the class of models of the static spherically symmetric boson-fermion stars in the scalar-tensor theory of gravity with massive dilaton field. The proper mathematical model of such stars is interpreted as a nonlinear two-parametric eigenvalue problem. The first of the parameters is the unknown internal boundary (the radius of the fermionic part of the star) Rs, and the second one represents the frequency Ω of the time oscillations of the boson field. To solve this problem, the whole space [0, ∞) is splitted into two domains: internal [0, Rs] (inside the star) and external [Rs, ∞) (outside the star). In each domain the physical model leads to two nonlinear boundary value problems in respect to metric functions, the functions describing the fermionic and bosonic matter, and the dilaton field. These boundary value problems have different dimensions inside and outside the star, respectively. The solutions in these regions are obtained separately and matched using the necessary algebraic continuity conditions including Rs and Ω. The continuous analogue of the Newton method for solving both the nonlinear differential and algebraic problems is used. The corresponding linearized boundary value problems at each iteration are solved by means of spline-collocation scheme. In this way, we obtain the behaviour of the basic geometric quantities and functions describing a dilaton field and matter fields, which build the star
Salas, P.; Fortes, M.; Solís, M. A.; Sevilla, F. J.
2016-05-01
We adapt the Boson-Fermion superconductivity model to include layered systems such as underdoped cuprate superconductors. These systems are represented by an infinite layered structure containing a mixture of paired and unpaired fermions. The former, which stand for the superconducting carriers, are considered as noninteracting zero spin composite-bosons with a linear energy-momentum dispersion relation in the CuO2 planes where superconduction is predominant, coexisting with the unpaired fermions in a pattern of stacked slabs. The inter-slab, penetrable, infinite planes are generated by a Dirac comb potential, while paired and unpaired electrons (or holes) are free to move parallel to the planes. Composite-bosons condense at a critical temperature at which they exhibit a jump in their specific heat. These two values are assumed to be equal to the superconducting critical temperature Tc and the specific heat jump reported for YBa2Cu3O6.80 to fix our model parameters namely, the plane impenetrability and the fraction of superconducting charge carriers. We then calculate the isochoric and isobaric electronic specific heats for temperatures lower than Tc of both, the composite-bosons and the unpaired fermions, which matches the latest experimental curves. From the latter, we extract the linear coefficient (γn) at Tc, as well as the quadratic (αT2) term for low temperatures. We also calculate the lattice specific heat from the ARPES phonon spectrum, and add it to the electronic part, reproducing the experimental total specific heat at and below Tc within a 5% error range, from which the cubic (ßT3) term for low temperatures is obtained. In addition, we show that this model reproduces the cuprates mass anisotropies.
BEC-polaron gas in a boson-fermion mixture: A many-body extension of Lee-Low-Pines theory
Nakano, Eiji; Yabu, Hiroyuki
2016-05-01
We investigate the ground state properties of the gaseous mixture of a single species of bosons and fermions at zero temperature, where bosons are major in population over fermions, and form the Bose-Einstein condensate (BEC). The boson-boson and boson-fermion interactions are assumed to be weakly repulsive and attractive, respectively, while the fermion-fermion interaction is absent due to the Pauli exclusion for the low energy s -wave scattering. We treat fermions as a gas of polarons dressed with Bogoliubov phonons, which is an elementary excitation of the BEC, and evaluate the ground state properties with the method developed by Lemmens, Devreese, and Brosens (LDB) originally for the electron polaron gas, and also with a general extension of the Lee-Low-Pines theory for many-body systems (eLLP), which incorporates the phonon drag effects as in the original LLP theory. The formulation of eLLP is developed and discussed in the present paper. The binding (interaction) energy of the polaron gas is calculated in these methods and shown to be finite (negative) for the dilute gas of heavy fermions with attractive boson-fermion interactions, though the suppression by the many-body effects exists.
Breaking of de Sitter Symmetry
Bander, Myron
2010-01-01
We show that an interacting spin-0 field on a de Sitter space background will break the underlying de Sitter symmetry. This is done first for a (1+1) de Sitter space where a boson-fermion correspondence permits us to solve certain interacting theories by transforming them into free ones of opposite statistics. A massless boson interacting by a sine-Gordon potential is shown to be equivalent to a free massive fermion with the mass depending on the de Sitter time thus breaking the symmetry explicitly. We then show that for larger dimensions and any boson potential, to one loop, an anomaly develops and the currents generating the de Sitter transformations are not conserved.
Energy Technology Data Exchange (ETDEWEB)
Gollwitzer, A.; Hertenberger, R.; Metz, A.; Schiemenz, P.; Valnion, B.D.; Graw, G. [Sektion Physik der Universitaet Muenchen, D-85748 Garching (Germany); Blasi, N.; Lucchini, S.; Micheletti, S.; Pignanelli, M. [Dipartimento di Fisica dellUniversita di Milano, I-20133 Milano (Italy); de Leo, R. [Universita di Bari and Sezione INFN di Bari (Italy); Gill, R.L. [Brookhaven National Laboratory, Upton, New York 11973 (United States); Hategan, C. [Institute of Atomic Physics, Bukarest (Romania); Casten, R.F. [Yale University, A.W. Wright Nuclear Structure Laboratory, New Haven, Connecticut 06520 (United States)
1998-06-01
The {sup 154}Sm({rvec d},t) reaction at high energy resolution (n,{gamma}), average resonance capture (ARC), and coincidence measurements were performed to study the deformed nucleus {sup 153}Sm. Strength distributions from ({rvec d},t) and completeness for I{sup {pi}}= (1) /(2) {sup {minus}} and (3) /(2) {sup {minus}} states up to 1500 keV from ARC provide one of the first detailed tests of the interacting boson fermion model (IBFM) in a deformed nucleus in a multiorbit environment. For negative parity states the model accounts for the large number of low spin ( (1) /(2) {sup {minus}}, (3) /(2) {sup {minus}}) states much better than the Nilsson model since the even-even core in the IBFM calculations automatically includes excited vibrational states. The IBFM calculations also predict (d,t) spectroscopic factors better than the Nilsson model with pairing and Coriolis mixing. Neither the IBFM nor the Nilsson approach can explain the low lying positive parity states. The IBFM calculations show that for certain combinations of parameters, the monopole term in the boson-fermion Hamiltonian has more than a scaling effect: it can attenuate the Coriolis mixing (energy staggering). Finally suggested improvements in the treatment of pairing in the IBFM are made. {copyright} {ital 1998} {ital The American Physical Society}
International Nuclear Information System (INIS)
Several aspect of shape phase transitions and critical point symmetries are reviewed in this contribution within the frameworks of the Interacting Boson Model (IBM) and the Interacting Boson Fermion Model (IBFM) for even and odd systems respectively and compared with collective geometric models. We discuss in particular the case of an odd j = 3/2 particle coupled to an even-even boson core that undergoes a transition from the spherical limit U(5) to the γ-unstable limit O(6). The spectrum and transition rates at the critical point are similar to those of the even core and they agree qualitatively with the E(5/4) boson-fermion symmetry. We discuss also the UBF (5) to SUBF (3) shape phase transition in which the allowed fermionic orbitals are j = 1/2; 3/2; 5/2. The formalism of the intrinsic or coherent states is used to describe in details the ground state as well as the excited β- and γ- bands. This formalism is also used to calculate the Potential Energy Surface of the cubic quadrupole operator that leads to triaxiality. (author)
Symmetries, Symmetry Breaking, Gauge Symmetries
Strocchi, Franco
2015-01-01
The concepts of symmetry, symmetry breaking and gauge symmetries are discussed, their operational meaning being displayed by the observables {\\em and} the (physical) states. For infinitely extended systems the states fall into physically disjoint {\\em phases} characterized by their behavior at infinity or boundary conditions, encoded in the ground state, which provide the cause of symmetry breaking without contradicting Curie Principle. Global gauge symmetries, not seen by the observables, are nevertheless displayed by detectable properties of the states (superselected quantum numbers and parastatistics). Local gauge symmetries are not seen also by the physical states; they appear only in non-positive representations of field algebras. Their role at the Lagrangian level is merely to ensure the validity on the physical states of local Gauss laws, obeyed by the currents which generate the corresponding global gauge symmetries; they are responsible for most distinctive physical properties of gauge quantum field ...
Frustration and time-reversal symmetry breaking for Fermi and Bose-Fermi systems
Sacha, Krzysztof; Targońska, Katarzyna; Zakrzewski, Jakub
2012-05-01
The modulation of an optical lattice potential that breaks time-reversal symmetry enables the realization of complex tunneling amplitudes in the corresponding tight-binding model. For a superfluid Fermi gas in a triangular lattice potential with complex tunnelings, the pairing function acquires a complex phase, so the frustrated magnetism of fermions can be realized. Bose-Fermi mixtures of bosonic molecules and unbound fermions in the lattice also show interesting behavior. Due to boson-fermion coupling, the fermions become enslaved by the bosons and the corresponding pairing function takes the complex phase determined by the bosons. In the presence of bosons the Fermi system can reveal both gapped and gapless superfluidity.
Boson-fermion stars exploring different configurations
Henriques, A B; Henriques, Alfredo B.; Mendes, Luis E.
2003-01-01
We use the flexibility of the concept of a fermion-boson star to explore different configurations, ranging from objects of atomic size and masses of the order $10^{18}$ g, up to objects of galactic masses and gigantic halos around a smaller core, with possible interesting applications to astrophysics and cosmology, particularly in the context of dark matter.
Symmetries and Symmetry Breaking
Van Oers, W T H
2003-01-01
In understanding the world of matter, the introduction of symmetry principles following experimentation or using the predictive power of symmetry principles to guide experimentation is most profound. The conservation of energy, linear momentum, angular momentum, charge, and CPT involve fundamental symmetries. All other conservation laws are valid within a restricted subspace of the four interactions: the strong, the electromagnetic, the weak, and the gravitational interaction. In this paper comments are made regarding parity violation in hadronic systems, charge symmetry breaking in two nucleon and few nucleon systems, and time-reversal-invariance in hadronic systems.
International Nuclear Information System (INIS)
Complete sets of low-lying 1/2- and 3/2- levels in 185W and 187W have been obtained using measurements of primary γ-rays following average resonance neutron capture at mean incident neutron energies of 2 and 24 keV. The results are discussed in terms of both the Nilsson model and the SU(3) boson-fermion symmetry scheme appropriate to this region. The data highlights the advantages and deficiencies of both frameworks, and shows that neither is able to describe the complete spectrum of low-lying low-spin energy levels. The two approaches are outlined and compared and the role of the missing degrees of freedom in each is discussed. (orig.)
Retarded Boson-Fermion interaction in atomic systems
Indian Academy of Sciences (India)
Sambhu N Datta
2007-09-01
The retarded interaction between an electron and a spin-0 nucleus, that has been derived from electro-dynamical perturbation theory is discussed here. A brief account of the derivation is given. The retarded form is correct through order 2/2. Use of the relative coordinates leads to an effective oneelectron operator that can be used through all orders of perturbation theory. A few unitary transformations give rise to the interaction that is valid in the non-relativistic limit.
Bosons, fermions and anyons in the plane, and supersymmetry
Horvathy, Peter A; Valenzuela, Mauricio
2010-01-01
Universal vector wave equations allowing for a unified description of anyons, and also of usual bosons and fermions in the plane are proposed. The existence of two essentially different types of anyons, based on unitary and also on non-unitary infinite-dimensional half-bounded representations of the (2+1)D Lorentz algebra is revealed. Those associated with non-unitary representations interpolate between bosons and fermions. The extended formulation of the theory includes the previously known Jackiw-Nair (JN) and Majorana-Dirac (MD) descriptions of anyons as particular cases, and allows us to compose bosons and fermions from entangled anyons. The theory admits a simple supersymmetric generalization, in which the JN and MD systems are unified in N=1 and N=2 supermultiplets. Two different non-relativistic limits of the theory are investigated. The usual one generalizes Levy-Leblond's spin 1/2 theory to arbitrary spin, as well as to anyons. The second, "Jackiw-Nair" limit (that corresponds to Inonu-Wigner contrac...
Attanucci, Frank J.; Losse, John
2008-01-01
In a first calculus course, it is not unusual for students to encounter the theorems which state: If f is an even (odd) differentiable function, then its derivative is odd (even). In our paper, we prove some theorems which show how the symmetry of a continuous function f with respect to (i) the vertical line: x = a or (ii) with respect to the…
International Nuclear Information System (INIS)
We present many varied chiral symmetry models at the quark level which consistently describe strong interaction hadron dynamics. The pattern that emerges is a nonstrange current quark mass scale mcur ≅ (34-69) MeV and a current quark mass ratio (ms/m)cur ≅ 5-6 along with no strange quark content in nucleons. (orig./WL)
LIE SYMMETRIES AND NOETHER SYMMETRIES
Directory of Open Access Journals (Sweden)
PGL Leach
2012-10-01
Full Text Available We demonstrate that so-called nonnoetherian symmetries with which a known first integral is associated of a differential equation derived from a Lagrangian are in fact noetherian. The source of the misunderstanding lies in the nonuniqueness of the Lagrangian.
Symmetry, Symmetry Breaking and Topology
Directory of Open Access Journals (Sweden)
Siddhartha Sen
2010-07-01
Full Text Available The ground state of a system with symmetry can be described by a group G. This symmetry group G can be discrete or continuous. Thus for a crystal G is a finite group while for the vacuum state of a grand unified theory G is a continuous Lie group. The ground state symmetry described by G can change spontaneously from G to one of its subgroups H as the external parameters of the system are modified. Such a macroscopic change of the ground state symmetry of a system from G to H correspond to a “phase transition”. Such phase transitions have been extensively studied within a framework due to Landau. A vast range of systems can be described using Landau’s approach, however there are also systems where the framework does not work. Recently there has been growing interest in looking at such non-Landau type of phase transitions. For instance there are several “quantum phase transitions” that are not of the Landau type. In this short review we first describe a refined version of Landau’s approach in which topological ideas are used together with group theory. The combined use of group theory and topological arguments allows us to determine selection rule which forbid transitions from G to certain of its subgroups. We end by making a few brief remarks about non-Landau type of phase transition.
International Nuclear Information System (INIS)
The sky uniformity can be noticed in studying the repartition of objects far enough. The sky isotropy description uses space rotations. The group theory elements will allow to give a meaning at the same time precise and general to the word a ''symmetry''. Universe models are reviewed, which must have both of the following qualities: - conformity with the physic known laws; - rigorous symmetry following one of the permitted groups. Each of the models foresees that universe evolution obeys an evolution equation. Expansion and big-bang theory are recalled. Is universe an open or closed space. Universe is also electrically neutral. That leads to a work hypothesis: the existing matter is not given data of universe but it appeared by evolution from nothing. Problem of matter and antimatter is then raised up together with its place in universe
Peters, Kirstin
2010-01-01
A well-known result by Palamidessi tells us that {\\pi}mix (the {\\pi}-calculus with mixed choice) is more expressive than {\\pi}sep (its subset with only separate choice). The proof of this result argues with their different expressive power concerning leader election in symmetric networks. Later on, Gorla of- fered an arguably simpler proof that, instead of leader election in symmetric networks, employed the reducibility of "incestual" processes (mixed choices that include both enabled senders and receivers for the same channel) when running two copies in parallel. In both proofs, the role of breaking (ini- tial) symmetries is more or less apparent. In this paper, we shed more light on this role by re-proving the above result-based on a proper formalization of what it means to break symmetries-without referring to another layer of the distinguishing problem domain of leader election. Both Palamidessi and Gorla rephrased their results by stating that there is no uniform and reason- able encoding from {\\pi}mix i...
CP and other Symmetries of Symmetries
Trautner, Andreas
2016-01-01
Outer automorphisms of symmetries ("symmetries of symmetries") in relativistic quantum field theories are studied, including charge conjugation (C), space-reflection (P) , and time-reversal (T) transformations. The group theory of outer automorphisms is pedagogically introduced and it is shown that CP transformations are special outer automorphisms of the global, local, and space-time symmetries of a theory. It is shown that certain discrete groups allow for a group theoretical prediction of parameter independent CP violating complex phases with fixed geometrical values. The remainder of this thesis pioneers the study of outer automorphisms which are not related to C, P, or T. It is shown how outer automorphisms, in general, relate symmetry invariants and, in theories with spontaneous symmetry breaking, imply relations between different vacuum expectation values. Thereby, outer automorphisms can give rise to emergent symmetries. An example model with a discrete symmetry and three copies of the Standard Model ...
International Nuclear Information System (INIS)
Internal and space-time symmetries are discussed in this group of lectures. The first of the lectures deals with an internal symmetry, or rather two related symmetries called charge independence and charge symmetry. The next two discuss space-time symmetries which also hold approximately, but are broken only by the weak forces; that is, these symmetries hold for both the hadronic and electromagnetic forces
Chiral symmetry and chiral-symmetry breaking
International Nuclear Information System (INIS)
These lectures concern the dynamics of fermions in strong interaction with gauge fields. Systems of fermions coupled by gauge forces have a very rich structure of global symmetries, which are called chiral symmetries. These lectures will focus on the realization of chiral symmetries and the causes and consequences of thier spontaneous breaking. A brief introduction to the basic formalism and concepts of chiral symmetry breaking is given, then some explicit calculations of chiral symmetry breaking in gauge theories are given, treating first parity-invariant and then chiral models. These calculations are meant to be illustrative rather than accurate; they make use of unjustified mathematical approximations which serve to make the physics more clear. Some formal constraints on chiral symmetry breaking are discussed which illuminate and extend the results of our more explicit analysis. Finally, a brief review of the phenomenological theory of chiral symmetry breaking is presented, and some applications of this theory to problems in weak-interaction physics are discussed
Jaffé, Hans H
1977-01-01
This book, devoted exclusively to symmetry in chemistry and developed in an essentially nonmathematical way, is a must for students and researchers. Topics include symmetry elements and operations, multiple symmetry operations, multiplication tables and point groups, group theory applications, and crystal symmetry. Extensive appendices provide useful tables.
Rasin, A
1994-01-01
We discuss the idea of approximate flavor symmetries. Relations between approximate flavor symmetries and natural flavor conservation and democracy models is explored. Implications for neutrino physics are also discussed.
Nilles, H. P.; Ratz, M.; Vaudrevange, P. K. S.
2012-01-01
Discrete (family) symmetries might play an important role in models of elementary particle physics. We discuss the origin of such symmetries in the framework of consistent ultraviolet completions of the standard model in field and string theory. The symmetries can arise due to special geometrical properties of extra compact dimensions and the localization of fields in this geometrical landscape. We also comment on anomaly constraints for discrete symmetries.
Energy Technology Data Exchange (ETDEWEB)
Nilles, Hans Peter [Bonn Univ. (Germany). Bethe Center for Theoretical Physics; Bonn Univ. (Germany). Physikalisches Inst.; Ratz, Michael [Technische Univ. Muenchen, Garching (Germany). Physik-Department; Vaudrevange, Patrick K.S. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2012-04-15
Discrete (family) symmetries might play an important role in models of elementary particle physics. We discuss the origin of such symmetries in the framework of consistent ultraviolet completions of the standard model in field and string theory. The symmetries can arise due to special geometrical properties of extra compact dimensions and the localization of fields in this geometrical landscape. We also comment on anomaly constraints for discrete symmetries.
Chiral symmetry and chiral-symmetry breaking
Energy Technology Data Exchange (ETDEWEB)
Peskin, M.E.
1982-12-01
These lectures concern the dynamics of fermions in strong interaction with gauge fields. Systems of fermions coupled by gauge forces have a very rich structure of global symmetries, which are called chiral symmetries. These lectures will focus on the realization of chiral symmetries and the causes and consequences of thier spontaneous breaking. A brief introduction to the basic formalism and concepts of chiral symmetry breaking is given, then some explicit calculations of chiral symmetry breaking in gauge theories are given, treating first parity-invariant and then chiral models. These calculations are meant to be illustrative rather than accurate; they make use of unjustified mathematical approximations which serve to make the physics more clear. Some formal constraints on chiral symmetry breaking are discussed which illuminate and extend the results of our more explicit analysis. Finally, a brief review of the phenomenological theory of chiral symmetry breaking is presented, and some applications of this theory to problems in weak-interaction physics are discussed. (WHK)
Symmetry Analysis of Telegraph Equation
Nadjafikhah, Mehdi; Hejazi, Seyed Reza
2010-01-01
Lie symmetry group method is applied to study the Telegraph equation. The symmetry group and its optimal system are given, and group invariant solutions associated to the symmetries are obtained. Finally the structure of the Lie algebra symmetries is determined.
Symmetries in subatomic systems
International Nuclear Information System (INIS)
The underlying common themes of the EJC-2010 are symmetries and symmetry violation in relation to nucleon structure, nuclear geometry, isospin and reaction dynamics. The parity violation in electron scattering is the unique probe of strange quarks in nucleons and of neutron skin in heavy nuclei. The use of dynamical symmetries or spectrum generating algebras for the solution of the nuclear many-body problem is reviewed. We also discuss the impact of the symmetries of quantum chromodynamics on the observed properties of hadrons and strongly interacting matter. Mean field approaches are widely used to study nuclear structure properties and correlations between nucleons are treated by symmetry-violating mean field approaches and symmetry properties are currently treated with beyond mean field approaches by using projection techniques. A paper focuses on properties of giant resonances (GR) and particularly on the relationship between GR and isospin symmetry. This document gathers the papers and/or slides of 10 presentations. (A.C.)
Symmetry and symmetry breaking in quantum mechanics
International Nuclear Information System (INIS)
In the world of infinitely small, the world of atoms, nuclei and particles, the quantum mechanics enforces its laws. The discovery of Quanta, this unbelievable castration of the Possible in grains of matter and radiation, in discrete energy levels compels us of thinking the Single to comprehend the Universal. Quantum Numbers, magic Numbers and Numbers sign the wave. The matter is vibration. To describe the music of the world one needs keys, measures, notes, rules and partition: one needs quantum mechanics. The particles reduce themselves not in material points as the scholars of the past centuries thought, but they must be conceived throughout the space, in the accomplishment of shapes of volumes. When Einstein asked himself whether God plays dice, there was no doubt among its contemporaries that if He exists He is a geometer. In a Nature reduced to Geometry, the symmetries assume their role in servicing the Harmony. The symmetries allow ordering the energy levels to make them understandable. They impose there geometrical rules to the matter waves, giving them properties which sometimes astonish us. Hidden symmetries, internal symmetries and newly conceived symmetries have to be adopted subsequently to the observation of some order in this world of Quanta. In turn, the symmetries provide new observables which open new spaces of observation
International Nuclear Information System (INIS)
Symmetry, disymmetry, chirality etc. are well-known topics in chemistry. But they cannot only be found on the molecular level of matter. Atoms and elementary particles in physics are also characterized by particular symmetry groups. Even living organisms and populations on the macroscopic level have functional properties of symmetry. The whole physical, chemical, and biological evolution seems to be regulated by the emergence of new symmetries and the breaking down of old ones. One is reminded of Heisenberg's famous statement: 'Die letzte Wurzel der Erscheinungen ist also nicht die Materie, sondern das mathematische Gesetz, die Symmetrie, die mathematische Form' (Wandlungen in den Grundlagen der Naturwissenschaften, 1959). Historically the belief in symmetry and simplicity of nature has a long philosophical tradition from the Pythagoreans, Plato and Greek astronomers to Kepler and modern scientists. Today, 'symmetries in nature' is a common topic of mathematics, physics, chemistry, and biology. A lot of Nobel prizes were given in honour of inquiries concerning symmetries in nature. The fascination of symmetries is not only motivated by science, but by art and religion too. Therefore 'symmetris in nature' is an interdisciplinary topic which may help to overcome C.P. Snow's 'Two Cultures' of natural sciences and humanities. (author) 17 refs., 21 figs
From physical symmetries to emergent gauge symmetries
Barceló, Carlos; Di Filippo, Francesco; Garay, Luis J
2016-01-01
Gauge symmetries indicate redundancies in the description of the relevant degrees of freedom of a given field theory and restrict the nature of observable quantities. One of the problems faced by emergent theories of relativistic fields is to understand how gauge symmetries can show up in systems that contain no trace of these symmetries at a more fundamental level. In this paper we start a systematic study aimed to establish a satisfactory mathematical and physical picture of this issue, dealing first with abelian field theories. We discuss how the trivialization, due to the decoupling and lack of excitation of some degrees of freedom, of the Noether currents associated with physical symmetries leads to emergent gauge symmetries in specific situations. An example of a relativistic field theory of a vector field is worked out in detail in order to make explicit how this mechanism works and to clarify the physics behind it. The interplay of these ideas with well-known results of importance to the emergent grav...
van der Schaft, A. J.
1987-01-01
It is argued that the existence of symmetries may simplify, as in classical mechanics, the solution of optimal control problems. A procedure for obtaining symmetries for the optimal Hamiltonian resulting from the Maximum Principle is given; this avoids the actual calculation of the optimal Hamiltonian. This procedure is based upon the notion of symmetry for the Hamiltonian system with inputs and outputs associated with an optimal control problem.
Gray, J E; Vogt, A
1997-01-01
Is symmetry informative? The answer is both yes and no. We examine what information and symmetry are and how they are related. Our approach is primarily mathematical, not because mathematics provides the final word, but because it provides an insightful and relatively precise starting point. Information theory treats transformations that messages undergo from source to destination. Symmetries are information that leave some property of interest unchanged. In this respect the studies of information and symmetry can both be regarded as a Quest for the identity transformation. PMID:9224554
2016-01-01
The Symmetry Festival is a science and art program series, the most important periodic event (see its history) to bring together scientists, artists, educators and practitioners interested in symmetry (its roots, what is behind, applications, etc.), or in the consequences of its absence.
Symmetries of Spectral Problems
Shabat, A.
Deriving abelian KdV and NLS hierarchies, we describe non-abelian symmetries and "pre-Lax" elementary approach to Lax pairs. Discrete symmetries of spectral problems are considered in Sect. 4.2. Here we prove Darboux classical theorem and discuss a modern theory of dressing chains.
Symmetries in Lagrangian Dynamics
Ferrario, Carlo; Passerini, Arianna
2007-01-01
In the framework of Noether's theorem, a distinction between Lagrangian and dynamical symmetries is made, in order to clarify some aspects neglected by textbooks. An intuitive setting of the concept of invariance of differential equations is presented. The analysis is completed by deriving the symmetry properties in the motion of a charged…
Meshkov, Sydney
2009-01-01
The study of the symmetries of nature has fascinated scientists for eons. The application of the formal mathematical description of symmetries during the last century has produced many breakthroughs in our understanding of the substructure of matter. In this talk, a number of these advances are discussed, and the important role that George Sudarshan played in their development is emphasized
Symmetry relation for helical plasmas: parity symmetry
International Nuclear Information System (INIS)
It is shown that a symmetry relation holds strictly in the LHD (Large Helical Device) type helical magnetic fields. The symmetry relation can be expressed explicitly in the rotating helical coordinate system. It is named as parity symmetry in helical systems. A new concept, - concept of even scalars, odd scalars, even vectors, odd vectors -, is introduced. Calculus of vector operation retains strictly the parity relations for these quantities. For example, the vector product of two vectors with same parity become a odd parity vector. The rotation of a vector field A, ∇ x A, has same parity characteristics with the vector A. It is concluded that the equilibrium magnetic field and current distribution are expressed by even parity vectors. Pressure distribution is expressed by an even parity scalar function. The parity symmetry relations conduct uniquely the power expansion form of equilibrium magnetic field and pressure distribution. Analytical expression for these quantities are obtained approximately by truncation of the power series. Closed magnetic surface, islands, chaotic field line region and divertor field lines are well reproduced by this simple model. (author)
Symmetry Effects in Computation
Yao, Andrew Chi-Chih
2008-12-01
The concept of symmetry has played a key role in the development of modern physics. For example, using symmetry, C.N. Yang and other physicists have greatly advanced our understanding of the fundamental laws of physics. Meanwhile, computer scientists have been pondering why some computational problems seem intractable, while others are easy. Just as in physics, the laws of computation sometimes can only be inferred indirectly by considerations of general principles such as symmetry. The symmetry properties of a function can indeed have a profound effect on how fast the function can be computed. In this talk, we present several elegant and surprising discoveries along this line, made by computer scientists using symmetry as their primary tool. Note from Publisher: This article contains the abstract only.
Loebbert, Florian
2016-01-01
In these introductory lectures we discuss the topic of Yangian symmetry from various perspectives. Forming the classical counterpart of the Yangian and an extension of ordinary Noether symmetries, first the concept of nonlocal charges in classical, two-dimensional field theory is reviewed. We then define the Yangian algebra following Drinfeld's original motivation to construct solutions to the quantum Yang-Baxter equation. Different realizations of the Yangian and its mathematical role as a Hopf algebra and quantum group are discussed. We demonstrate how the Yangian algebra is implemented in quantum, two-dimensional field theories and how its generators are renormalized. Implications of Yangian symmetry on the two-dimensional scattering matrix are investigated. We furthermore consider the important case of discrete Yangian symmetry realized on integrable spin chains. Finally we give a brief introduction to Yangian symmetry in planar, four-dimensional super Yang-Mills theory and indicate its impact on the dila...
On the symmetry breaking phenomenon
Birtea, Petre; Puta, Mircea; Ratiu, Tudor S.; Tudoran, Ruazvan Micu
2006-01-01
We investigate the problem of symmetry breaking in the framework of dynamical systems with symmetry on a smooth manifold. Two cases will be analyzed: general and Hamiltonian dynamical systems. We give sufficient conditions for symmetry breaking in both cases.
Counting trees using symmetries
Bernardi, Olivier
2012-01-01
We present a new approach for counting trees, and we apply it to count multitype Cayley trees and to prove the multivariate Lagrange inversion formula. The gist of our approach is to exploit the symmetries of refined enumerative formulas: proving these symmetries is easy, and once the symmetries are proved the formulas follow effortlessly. Somewhat surprisingly, our formula for the generating function of multitype Cayley trees appears to be new, and implies certain recent results by Bousquet-M\\'elou and Chapuy. We also adapt our approach to recover known enumerative formulas for cacti counted according to their degree distribution.
Schwichtenberg, Jakob
2015-01-01
This is a textbook that derives the fundamental theories of physics from symmetry. It starts by introducing, in a completely self-contained way, all mathematical tools needed to use symmetry ideas in physics. Thereafter, these tools are put into action and by using symmetry constraints, the fundamental equations of Quantum Mechanics, Quantum Field Theory, Electromagnetism, and Classical Mechanics are derived. As a result, the reader is able to understand the basic assumptions behind, and the connections between the modern theories of physics. The book concludes with first applications of the previously derived equations.
Symmetry in Boolean Satisfiability
Directory of Open Access Journals (Sweden)
Fadi A. Aloul
2010-06-01
Full Text Available This paper reviews recent approaches on how to accelerate Boolean Satisfiability (SAT search by exploiting symmetries in the problem space. SAT search algorithms traverse an exponentially large search space looking for an assignment that satisfies a set of constraints. The presence of symmetries in the search space induces equivalence classes on the set of truth assignments. The goal is to use symmetries to avoid traversing all assignments by constraining the search to visit a few representative assignments in each equivalence class. This can lead to a significant reduction in search runtime without affecting the completeness of the search.
Sequential flavor symmetry breaking
International Nuclear Information System (INIS)
The gauge sector of the standard model exhibits a flavor symmetry that allows for independent unitary transformations of the fermion multiplets. In the standard model the flavor symmetry is broken by the Yukawa couplings to the Higgs boson, and the resulting fermion masses and mixing angles show a pronounced hierarchy. In this work we connect the observed hierarchy to a sequence of intermediate effective theories, where the flavor symmetries are broken in a stepwise fashion by vacuum expectation values of suitably constructed spurion fields. We identify the possible scenarios in the quark sector and discuss some implications of this approach.
DEFF Research Database (Denmark)
Avery, John Scales; Rettrup, Sten; Avery, James Emil
In theoretical physics, theoretical chemistry and engineering, one often wishes to solve partial differential equations subject to a set of boundary conditions. This gives rise to eigenvalue problems of which some solutions may be very difficult to find. For example, the problem of finding...... such problems can be much reduced by making use of symmetry-adapted basis functions. The conventional method for generating symmetry-adapted basis sets is through the application of group theory, but this can be difficult. This book describes an easier method for generating symmetry-adapted basis sets...
Symmetry relation for helical plasma. Parity symmetry
International Nuclear Information System (INIS)
It is shown that a strict symmetry relation holds in the LHD (Large Helical Device) type helical magnetic field. The symmetry relation is expressed explicitly in the rotating helical coordinate system and named as parity symmetry in helical system. A new concept, -concept of even scalars, odd scalars, even vectors, odd vectors-, is introduced. Calculus of vector operation retains strictly the parity relations for these quantities. For example, the vector product of two vectors with same parity become an odd parity vector. The rotation of a vector field A, ∇xA, has same parity characteristics with that of the vector A. It is concluded that the equilibrium magnetic field and current distribution are expressed by even parity vectors. Pressure distribution is expressed by an even parity scalar function. The parity symmetry relations conduct uniquely the power expansion form of equilibrium magnetic field and pressure distribution. Analytical expressions for these quantities are obtained approximately by truncation of the power series. An example of vacuum helical magnetic field is shown in the following, B=∇xA+B0(0, 0, r0/r), A=Bp/a=-(p/3r)Y3-(p3/12r3)Y(X4+Y4), -(p/3r)X3-(p3/12r3)X(X4+Y4), -((X2-Y2)/2)(1-(Xcos(pφ)-Ysin(pφ))/4r)-(p4/6r4)X2Y2)=, where p, r0, a, Bp, B0 are constants for magnetic field. Rotating helical coordinate system is expressed by (X, Y, φ) and r≡r0+Xcos (pφ) - Ysin (pφ). Closed magnetic surface, islands, chaotic field line region and divertor field lines are well represented by this simple model. (author)
International Nuclear Information System (INIS)
The purpose of this course is to study the evolution of the symmetry concept and establish its influence in the knowledge of the fundamental laws of nature. Physicist have been using the symmetry concept in two ways: to solve problems and to search for new understanding of the world around us. In quantum physics symmetry plays a key role in gaining an understanding of the physical laws governing the behavior of matter and field systems. It provides, generally, a shortcut based on geometry for discovering the secrets of the Universe. Because it is believed that the laws of physics are invariant under discrete and continuous transformation operations of the space and time, there are continuous symmetries, for example, energy and momentum together with discrete ones corresponding to charge, parity and time reversal operations.
Global Bifurcations With Symmetry
Porter, J B
2001-01-01
Symmetry is a ubiquitous feature of physical systems with profound implications for their dynamics. This thesis investigates the role of symmetry in global bifurcations. In particular, the structure imposed by symmetry can encourage the formation of complex solutions such as heteroclinic cycles and chaotic invariant sets. The first study focuses on the dynamics of 1:n steady-state mode interactions in the presence of O(2) symmetry. The normal form equations considered are relevant to a variety of physical problems including Rayleigh-Bénard convection with periodic boundary conditions. In open regions of parameter space these equations contain structurally stable heteroclinic cycles composed of connections between standing wave, pure mode, and trivial solutions. These structurally stable cycles exist between two global bifurcations, the second of which involves an additional mixed mode state and creates as many as four distinct kinds of structurally unstable heteroclinic cycles. The various cycles c...
Gauge symmetry from decoupling
Wetterich, C
2016-01-01
Gauge symmetries emerge from a redundant description of the effective action for light degrees of freedom after the decoupling of heavy modes. This redundant description avoids the use of explicit constraints in configuration space. For non-linear constraints the gauge symmetries are non-linear. In a quantum field theory setting the gauge symmetries are local and can describe Yang-Mills theories or quantum gravity. We formulate gauge invariant fields that correspond to the non-linear light degrees of freedom. In the context of functional renormalization gauge symmetries can emerge if the flow generates or preserves large mass-like terms for the heavy degrees of freedom. They correspond to a particular form of gauge fixing terms in quantum field theories.
International Nuclear Information System (INIS)
In the present work, we elucidate the meaning of the custodial symmetry and its importance at the phenomenological level in the framework of the standard model of the electroweak interactions and its possible extensions. (Author)
Golubitsky, Martin
2012-04-01
Many gaits of four-legged animals are described by symmetry. For example, when a horse paces it moves both left legs in unison and then both right legs and so on. The motion is described by two symmetries: Interchange front and back legs, and swap left and right legs with a half-period phase shift. Biologists postulate the existence of a central pattern generator (CPG) in the neuronal system that sends periodic signals to the legs. CPGs can be thought of as electrical circuits that produce periodic signals and can be modeled by systems with symmetry. In this lecture we discuss animal gaits; use gait symmetries to construct a simplest CPG architecture that naturally produces quadrupedal gait rhythms; and make several testable predictions about gaits.
Second order symmetry operators
International Nuclear Information System (INIS)
Using systematic calculations in spinor language, we obtain simple descriptions of the second order symmetry operators for the conformal wave equation, the Dirac–Weyl equation and the Maxwell equation on a curved four-dimensional Lorentzian manifold. The conditions for existence of symmetry operators for the different equations are seen to be related. Computer algebra tools have been developed and used to systematically reduce the equations to a form which allows geometrical interpretation. (paper)
IBM: discrete symmetry viewpoint
International Nuclear Information System (INIS)
It is shown that the set of information of the s and d boson operators which maintain the IBM-like form of the Hamiltonian comprises a discrete point symmetry group D2'. The transformations manifest themselves as a parameter symmetry of the IBM-1 Hamiltonian. The transformations considered are also necessary for constructing the most general IBM-2 Hamiltonian. The properties of the potential energy surfaces arising in connection with these transformations are discussed
IBM: parameter symmetry, hidden symmetries and transformations of boson operators
International Nuclear Information System (INIS)
A symmetry of the parameter space of interacting boson models IBM-1 and IBM-2 is studied. The symmetry is associated with linear canonical transformations of boson operators, or, equivalently, with the existence of different realizations of the symmetry algebras of the models. The relevance of the parameter symmetry to physical observables is discussed. (Author)
International Nuclear Information System (INIS)
This thesis deals with the possibility of describing the flavor sector of the Standard Model of Particle Physics (with neutrino masses), that is the fermion masses and mixing matrices, with a discrete, non-abelian flavor symmetry. In particular, mass independent textures are considered, where one or several of the mixing angles are determined by group theory alone and are independent of the fermion masses. To this end a systematic analysis of a large class of discrete symmetries, the dihedral groups, is analyzed. Mass independent textures originating from such symmetries are described and it is shown that such structures arise naturally from the minimization of scalar potentials, where the scalars are gauge singlet flavons transforming non-trivially only under the flavor group. Two models are constructed from this input, one describing leptons, based on the group D4, the other describing quarks and employing the symmetry D14. In the latter model it is the quark mixing matrix element Vud - basically the Cabibbo angle - which is at leading order predicted from group theory. Finally, discrete flavor groups are discussed as subgroups of a continuous gauge symmetry and it is shown that this implies that the original gauge symmetry is broken by fairly large representations. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Blum, Alexander Simon
2009-06-10
This thesis deals with the possibility of describing the flavor sector of the Standard Model of Particle Physics (with neutrino masses), that is the fermion masses and mixing matrices, with a discrete, non-abelian flavor symmetry. In particular, mass independent textures are considered, where one or several of the mixing angles are determined by group theory alone and are independent of the fermion masses. To this end a systematic analysis of a large class of discrete symmetries, the dihedral groups, is analyzed. Mass independent textures originating from such symmetries are described and it is shown that such structures arise naturally from the minimization of scalar potentials, where the scalars are gauge singlet flavons transforming non-trivially only under the flavor group. Two models are constructed from this input, one describing leptons, based on the group D{sub 4}, the other describing quarks and employing the symmetry D{sub 14}. In the latter model it is the quark mixing matrix element V{sub ud} - basically the Cabibbo angle - which is at leading order predicted from group theory. Finally, discrete flavor groups are discussed as subgroups of a continuous gauge symmetry and it is shown that this implies that the original gauge symmetry is broken by fairly large representations. (orig.)
Regular Symmetry Patterns (Technical Report)
Lin, Anthony W.; Nguyen, Truong Khanh; Rümmer, Philipp; Sun, Jun
2015-01-01
Symmetry reduction is a well-known approach for alleviating the state explosion problem in model checking. Automatically identifying symmetries in concurrent systems, however, is computationally expensive. We propose a symbolic framework for capturing symmetry patterns in parameterised systems (i.e. an infinite family of finite-state systems): two regular word transducers to represent, respectively, parameterised systems and symmetry patterns. The framework subsumes various types of symmetry ...
International Nuclear Information System (INIS)
In unpolarized cross sections constraints imposed by symmetries produce only quantitative changes which, in the absence of the precise knowledge of dynamics, cannot be used to test the validity of those symmetries. In polarization observables, in sharp contrast, imposition of symmetries produces qualitative changes, such as the vanishing of some observables or linear relationships among observables, which can be used to check the validity of symmetries without a detailed knowledge of dynamics. Such polarization observables can also separate the different constraints caused by different symmetries imposed simultaneously. This is illustrated for the two cases when Lorentz invariance and parity conservation, and Lorentz invariance and time reversal invariance, respectively, hold. It is also shown that it is impossible to construct, in any reaction in atomic, nuclear, or particle physics, a null experiment that would unambiguously test the validity of time-reversal invariance independently of dynamical assumptions. Finally, for a general quantum mechanical system undergoing a process, it is shown that one can tell from measurements on this system whether or not the system is characterized by quantum numbers the existence of which is unknown to the observer, even though the detection equipment used by the observer is unable to distinguish among the various possible values of the secret quantum number and hence always averages over them. This allows us to say whether the spin of a particle in a reaction is zero or not even if they can measure nothing about that particle's polarization. 5 references
Baldo, M
2016-01-01
The nuclear symmetry energy characterizes the variation of the binding energy as the neutron to proton ratio of a nuclear system is varied. This is one of the most important features of nuclear physics in general, since it is just related to the two component nature of the nuclear systems. As such it is one of the most relevant physical parameters that affect the physics of many phenomena and nuclear processes. This review paper presents a survey of the role and relevance of the nuclear symmetry energy in different fields of research and of the accuracy of its determination from the phenomenology and from the microscopic many-body theory. In recent years, a great interest was devoted not only to the Nuclear Matter symmetry energy at saturation density but also to its whole density dependence, which is an essential ingredient for our understanding of many phenomena. We analyze the nuclear symmetry energy in different realms of nuclear physics and astrophysics. In particular we consider the nuclear symmetry ene...
Loebbert, Florian
2016-08-01
In these introductory lectures we discuss the topic of Yangian symmetry from various perspectives. Forming the classical counterpart of the Yangian and an extension of ordinary Noether symmetries, first the concept of nonlocal charges in classical, two-dimensional field theory is reviewed. We then define the Yangian algebra following Drinfel’d's original motivation to construct solutions to the quantum Yang–Baxter equation. Different realizations of the Yangian and its mathematical role as a Hopf algebra and quantum group are discussed. We demonstrate how the Yangian algebra is implemented in quantum, two-dimensional field theories and how its generators are renormalized. Implications of Yangian symmetry on the two-dimensional scattering matrix are investigated. We furthermore consider the important case of discrete Yangian symmetry realized on integrable spin chains. Finally we give a brief introduction to Yangian symmetry in planar, four-dimensional super Yang–Mills theory and indicate its impact on the dilatation operator and tree-level scattering amplitudes. These lectures are illustrated by several examples, in particular the two-dimensional chiral Gross–Neveu model, the Heisenberg spin chain and { N }=4 superconformal Yang–Mills theory in four dimensions.
Yi-Nan, Fang; Guo-Hui, Dong; Duan-Lu, Zhou; Chang-Pu, Sun
2016-04-01
Symmetry is conventionally described in a polarized manner that the system is either completely symmetric or completely asymmetric. Using group theoretical approach to overcome this dichotomous problem, we introduce the degree of symmetry (DoS) as a non-negative continuous number ranging from zero to unity. DoS is defined through an average of the fidelity deviations of Hamiltonian or quantum state over its transformation group G, and thus is computable by making use of the completeness relations of the irreducible representations of G. The monotonicity of DoS can effectively probe the extended group for accidental degeneracy while its multi-valued natures characterize some (spontaneous) symmetry breaking. Supported by the National Natural Science Foundation of China under Grant Nos. 11421063, 11534002, 11475254 and the National 973 Program under Grant Nos. 2014CB921403, 2012CB922104, and 2014CB921202
International Nuclear Information System (INIS)
The Higgs mechanism is reviewed in its most general form, requiring the existence of a new symmetry-breaking force and associated particles, which need not however be Higgs bosons. The first lecture reviews the essential elements of the Higgs mechanism, which suffice to establish low energy theorems for the scattering of longitudinally polarized W and Z gauge bosons. An upper bound on the scale of the symmetry-breaking physics then follows from the low energy theorems and partial wave unitarity. The second lecture reviews particular models, with and without Higgs bosons, paying special attention to how the general features discussed in lecture 1 are realized in each model. The third lecture focuses on the experimental signals of strong WW scattering that can be observed at the SSC above 1 TeV in the WW subenergy, which will allow direct measurement of the strength of the symmetry-breaking force. 52 refs., 10 figs
Binary Tetrahedral Flavor Symmetry
Eby, David A
2013-01-01
A study of the T' Model and its variants utilizing Binary Tetrahedral Flavor Symmetry. We begin with a description of the historical context and motivations for this theory, together with some conceptual background for added clarity, and an account of our theory's inception in previous works. Our model endeavors to bridge two categories of particles, leptons and quarks, a unification made possible by the inclusion of additional Higgs particles, shared between the two fermion sectors and creating a single coherent system. This is achieved through the use of the Binary Tetrahedral symmetry group and an investigation of the Tribimaximal symmetry evidenced by neutrinos. Our work details perturbations and extensions of this T' Model as we apply our framework to neutrino mixing, quark mixing, unification, and dark matter. Where possible, we evaluate model predictions against experimental results and find excellent matching with the atmospheric and reactor neutrino mixing angles, an accurate prediction of the Cabibb...
Weiss, Asia; Whiteley, Walter
2014-01-01
This book contains recent contributions to the fields of rigidity and symmetry with two primary focuses: to present the mathematically rigorous treatment of rigidity of structures, and to explore the interaction of geometry, algebra, and combinatorics. Overall, the book shows how researchers from diverse backgrounds explore connections among the various discrete structures with symmetry as the unifying theme. Contributions present recent trends and advances in discrete geometry, particularly in the theory of polytopes. The rapid development of abstract polytope theory has resulted in a rich theory featuring an attractive interplay of methods and tools from discrete geometry, group theory, classical geometry, hyperbolic geometry and topology. The volume will also be a valuable source as an introduction to the ideas of both combinatorial and geometric rigidity theory and its applications, incorporating the surprising impact of symmetry. It will appeal to students at both the advanced undergraduate and gradu...
Hidden Symmetry Subgroup Problems
Decker, Thomas; Santha, Miklos; Wocjan, Pawel
2011-01-01
We advocate a new approach of addressing hidden structure problems and finding efficient quantum algorithms. We introduce and investigate the Hidden Symmetry Subgroup Problem (HSSP), which is a generalization of the well-studied Hidden Subgroup Problem (HSP). Given a group acting on a set and an oracle whose level sets define a partition of the set, the task is to recover the subgroup of symmetries of this partition inside the group. The HSSP provides a unifying framework that, besides the HSP, encompasses a wide range of algebraic oracle problems, including quadratic hidden polynomial problems. While the HSSP can have provably exponential quantum query complexity, we obtain efficient quantum algorithms for various interesting cases. To achieve this, we present a general method for reducing the HSSP to the HSP, which works efficiently in several cases related to symmetries of polynomials. The HSSP therefore connects in a rather surprising way certain hidden polynomial problems with the HSP. Using this connect...
Beyond-mean-field boson-fermion model for odd-mass nuclei
Nomura, K.; Nikšić, T.; Vretenar, D.
2016-05-01
A novel method for calculating spectroscopic properties of medium-mass and heavy atomic nuclei with an odd number of nucleons is introduced, based on the framework of nuclear energy density functional theory and the particle-core coupling scheme. The deformation energy surface of the even-even core, as well as the spherical single-particle energies and occupation probabilities of the odd particle(s), are obtained in a self-consistent mean-field calculation determined by the choice of the energy density functional and pairing interaction. This method uniquely determines the parameters of the Hamiltonian of the boson core, and only the strength of the particle-core coupling is specifically adjusted to selected data for a particular nucleus. The approach is illustrated in a systematic study of low-energy excitation spectra and transition rates of axially deformed odd-mass Eu isotopes.
Beyond mean-field boson-fermion model for odd-mass nuclei
Nomura, K; Vretenar, D
2016-01-01
A novel method for calculating spectroscopic properties of medium-mass and heavy atomic nuclei with an odd number of nucleons is introduced, based on the framework of nuclear energy density functional theory and the particle-core coupling scheme. The deformation energy surface of the even-even core, as well as the spherical single-particle energies and occupation probabilities of the odd particle(s), are obtained in a self-consistent mean-field calculation determined by the choice of the energy density functional and pairing interaction. This method uniquely determines the parameters of the Hamiltonian of the boson core, and only the strength of the particle-core coupling is specifically adjusted to selected data for a particular nucleus. The approach is illustrated in a systematic study of low-energy excitation spectra and transition rates of axially deformed odd-mass Eu isotopes.
Formation of Singlet Fermion Pairs in the Dilute Gas of Boson-Fermion Mixture
Directory of Open Access Journals (Sweden)
Samoilov V.
2010-10-01
Full Text Available We argue the formation of a free neutron spinless pairs in a liquid helium -dilute neutron gas mixture. We show that the term, of the interaction between the excitations of the Bose gas and the density modes of the neutron, meditate an attractive interaction via the neutron modes, which in turn leads to a bound state on a spinless neutron pair. Due to presented theoretical approach, we prove that the electron pairs in superconductivity could be discovered by Froelich earlier then it was made by the Cooper.
Free expansion of fermionic dark solitons in a boson-fermion mixture
International Nuclear Information System (INIS)
We use a time-dependent dynamical mean-field-hydrodynamic model to study the formation of fermionic dark solitons in a trapped degenerate Fermi gas mixed with a Bose-Einstein condensate in a harmonic as well as a periodic optical-lattice potential. The dark soliton with a 'notch' in the probability density with a zero at the minimum is simulated numerically as a nonlinear continuation of the first vibrational excitation of the linear mean-field-hydrodynamic equations, as suggested recently for pure bosons. We study the free expansion of these dark solitons as well as the consequent increase in the size of their central notch and discuss the possibility of experimental observation of the notch after free expansion
Formation of Singlet Fermion Pairs in the Dilute Gas of Boson-Fermion Mixture
Directory of Open Access Journals (Sweden)
Minasyan V.
2010-10-01
Full Text Available We argue the formation of a free neutron spinless pairs in a liquid helium -dilute neutron gas mixture. We show that the term, of the interaction between the excitations of the Bose gas and the density modes of the neutron, meditate an attractive interaction via the neutron modes, which in turn leads to a bound state on a spinless neutron pair. Due to presented theoretical approach, we prove that the electron pairs in superconductivity could be discovered by Frölich earlier then it was made by the Cooper.
de Vega, H. J.; Medrano, M. Ramon; Sanchez, N.
1992-07-01
We investigate the physical implications and particle content of superstring scattering in the supergravity shock-wave background recently found by us. The amplitudes for the different particle transmutation processes taking place in this geometry are explicitly computed for Gree-Schwarz superstring, including the new phenomena of fermion to boson and boson to fermion transmutations. Transition amplitudes among the ground states, first and second excited states are obtained. Particularly interesting are the amplitudes within the massless particle sector, which lead to physical massive particles upon supersymmetry breaking at low energies.
Observed supersymmetry in baryon and meson spectra with IBFM, the interacting boson fermion model
International Nuclear Information System (INIS)
Supersymetry is already observed in (i) nuclear physics where the same empirical formula based on a graded Lie group describles even-even and odd-even nuclear spectra and (ii) in Nambu-BCS theory where there is a simple relationship between the energy gap of the basic fermion and the bosonic collective modes. Similar relationships between large number of mesonic and baryonic excitations based on the SU(3) substructure in the U(15/30) graded Lie group, are proposed. (author)
Symmetry, structure, and spacetime
Rickles, Dean
2007-01-01
In this book Rickles considers several interpretative difficulties raised by gauge-type symmetries (those that correspond to no change in physical state). The ubiquity of such symmetries in modern physics renders them an urgent topic in philosophy of physics. Rickles focuses on spacetime physics, and in particular classical and quantum general relativity. Here the problems posed are at their most pathological, involving the apparent disappearance of spacetime! Rickles argues that both traditional ontological positions should be replaced by a structuralist account according to which relational
Foot, R; Volkas, R R
1992-01-01
Quark-lepton symmetric models are a class of gauge theories motivated by the similarities between the quarks and leptons. In these models the gauge group of the standard model is extended to include a ``color'' group for the leptons. Consequently, the quarks and leptons can then be related by a $Z_2$ discrete quark-lepton symmetry which is spontaneously broken by the vacuum. Models utilizing quark-lepton symmetry with acceptable and interesting collider phenomenology have been constructed. The cosmological consequences of these models are also discussed.
Arzano, Michele
2016-01-01
We construct discrete symmetry transformations for deformed relativistic kinematics based on group valued momenta. We focus on the specific example of kappa-deformations of the Poincare algebra with associated momenta living on (a sub-manifold of) de Sitter space. Our approach relies on the description of quantum states constructed from deformed kinematics and the observable charges associated with them. The results we present provide the first step towards the analysis of experimental bounds on the deformation parameter kappa to be derived via precision measurements of discrete symmetries and CPT.
Liu, Keh-Fei
2016-01-01
The relevance of chiral symmetry in baryons is highlighted in three examples in the nucleon spectroscopy and structure. The first one is the importance of chiral dynamics in understanding the Roper resonance. The second one is the role of chiral symmetry in the lattice calculation of $\\pi N \\sigma$ term and strangeness. The third one is the role of chiral $U(1)$ anomaly in the anomalous Ward identity in evaluating the quark spin and the quark orbital angular momentum. Finally, the chiral effective theory for baryons is discussed.
Measures with symmetry properties
Schindler, Werner
2003-01-01
Symmetries and invariance principles play an important role in various branches of mathematics. This book deals with measures having weak symmetry properties. Even mild conditions ensure that all invariant Borel measures on a second countable locally compact space can be expressed as images of specific product measures under a fixed mapping. The results derived in this book are interesting for their own and, moreover, a number of carefully investigated examples underline and illustrate their usefulness and applicability for integration problems, stochastic simulations and statistical applications.
International Nuclear Information System (INIS)
We review the current status of heavy-quark symmetry and its applications to weak decays of hadrons containing a single heavy quark. After an introduction to the underlying physical ideas, we discuss in detail the formalism of the heavy-quark effective theory, including a comprehensive treatment of symmetry breaking corrections. We then illustrate some nonperturbative approaches, which aim at a dynamical, QCD-based calculation of the universal form factors of the effective theory. The main focus is on results obtained using QCD sum rules. Finally, we perform an essentially model-independent analysis of semileptonic B meson decays in the context of the heavy-quark effective theory. ((orig.))
International Nuclear Information System (INIS)
The vanishing of the one-loop string cosmological constant in nontrivial nonsupersymmetric backgrounds can be understood by viewing the path integral as an inner product of orthogonal wave functions. For special backgrounds the string theory has an extra symmetry, expressed as a transformation on moduli space. When left- and right-moving wave functions transform in different representations of this symmetry the cosmological constant must vanish. Specific examples of the mechanism are given at one loop for theories in two and four dimensions. Various suggestions are made for the higher loop extension of this idea. (orig.)
Weakly broken galileon symmetry
Energy Technology Data Exchange (ETDEWEB)
Pirtskhalava, David [Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa (Italy); Santoni, Luca; Trincherini, Enrico [Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa (Italy); INFN, Sezione di Pisa, Piazza dei Cavalieri 7, 56126 Pisa (Italy); Vernizzi, Filippo [Institut de Physique Théorique, Université Paris Saclay, CEA, CNRS, Gif-sur-Yvette cédex, F-91191 (France)
2015-09-01
Effective theories of a scalar ϕ invariant under the internal galileon symmetryϕ→ϕ+b{sub μ}x{sup μ} have been extensively studied due to their special theoretical and phenomenological properties. In this paper, we introduce the notion of weakly broken galileon invariance, which characterizes the unique class of couplings of such theories to gravity that maximally retain their defining symmetry. The curved-space remnant of the galileon’s quantum properties allows to construct (quasi) de Sitter backgrounds largely insensitive to loop corrections. We exploit this fact to build novel cosmological models with interesting phenomenology, relevant for both inflation and late-time acceleration of the universe.
Arzano, Michele; Kowalski-Glikman, Jerzy
2016-09-01
We construct discrete symmetry transformations for deformed relativistic kinematics based on group valued momenta. We focus on the specific example of κ-deformations of the Poincaré algebra with associated momenta living on (a sub-manifold of) de Sitter space. Our approach relies on the description of quantum states constructed from deformed kinematics and the observable charges associated with them. The results we present provide the first step towards the analysis of experimental bounds on the deformation parameter κ to be derived via precision measurements of discrete symmetries and CPT.
Introduction to chiral symmetry
International Nuclear Information System (INIS)
These lectures are an attempt to a pedagogical introduction into the elementary concepts of chiral symmetry in nuclear physics. Effective chiral models such as the linear and nonlinear sigma model will be discussed as well as the essential ideas of chiral perturbation theory. Some applications to the physics of ultrarelativistic heavy ion collisions will be presented
Clader, Emily
2014-01-01
These expository notes are based on lectures by Yongbin Ruan during a special semester on the B-model at the University of Michigan in Winter 2014. They outline and compare the mirror symmetry constructions of Batyrev-Borisov, Hori-Vafa, and Bergland-Hubsch-Krawitz.
Fields, symmetries, and quarks
International Nuclear Information System (INIS)
'Fields, symmetries, and quarks' covers elements of quantum field theory, symmetries, gauge field theories and phenomenological descriptions of hadrons, with special emphasis on topics relevant to nuclear physics. It is aimed at nuclear physicists in general and at scientists who need a working knowledge of field theory, symmetry principles of elementary particles and their interactions and the quark structure of hadrons. The book starts out with an elementary introduction into classical field theory and its quantization. As gauge field theories require a working knowledge of global symmetries in field theories this topic is then discussed in detail. The following part is concerned with the general structure of gauge field theories and contains a thorough discussion of the still less widely known features of Non-Abelian gauge field theories. Quantum Chromodynamics (QCD), which is important for the understanding of hadronic matter, is discussed in the next section together with the quark compositions of hadrons. The last two chapters give a detailed discussion of phenomenological bag-models. The MIT bag is discussed, so that all theoretical calculations can be followed step by step. Since in all other bag-models the calculational methods and steps are essentially identical, this chapter should enable the reader to actually perform such calculations unaided. A last chapter finally discusses the topological bag-models which have become quite popular over the last few years. (orig.)
Gray, P L
2003-01-01
"The subatomic pion particle breaks the charge symmetry rule that governs both fusion and decay. In experiments performed at the Indiana University Cyclotron Laboratory, physicists forced heavy hydrogen (1 proton + 1 neutron) to fuse into helium in a controlled, measurable environment" (1 paragraph).
Symmetries in fundamental physics
Sundermeyer, Kurt
2014-01-01
Over the course of the last century it has become clear that both elementary particle physics and relativity theories are based on the notion of symmetries. These symmetries become manifest in that the "laws of nature" are invariant under spacetime transformations and/or gauge transformations. The consequences of these symmetries were analyzed as early as in 1918 by Emmy Noether on the level of action functionals. Her work did not receive due recognition for nearly half a century, but can today be understood as a recurring theme in classical mechanics, electrodynamics and special relativity, Yang-Mills type quantum field theories, and in general relativity. As a matter of fact, as shown in this monograph, many aspects of physics can be derived solely from symmetry considerations. This substantiates the statement of E.P.Wigner "... if we knew all the laws of nature, or the ultimate Law of nature, the invariance properties of these laws would not furnish us new information." Thanks to Wigner we now also underst...
Symmetries in fundamental physics
Sundermeyer, Kurt
2014-01-01
Over the course of the last century it has become clear that both elementary particle physics and relativity theories are based on the notion of symmetries. These symmetries become manifest in that the "laws of nature" are invariant under spacetime transformations and/or gauge transformations. The consequences of these symmetries were analyzed as early as in 1918 by Emmy Noether on the level of action functionals. Her work did not receive due recognition for nearly half a century, but can today be understood as a recurring theme in classical mechanics, electrodynamics and special relativity, Yang-Mills type quantum field theories, and in general relativity. As a matter of fact, as shown in this monograph, many aspects of physics can be derived solely from symmetry considerations. This substantiates the statement of E.P. Wigner "... if we knew all the laws of nature, or the ultimate Law of nature, the invariance properties of these laws would not furnish us new information." Thanks to Wigner we now also unders...
Gauging without Initial Symmetry
Kotov, Alexei
2016-01-01
The gauge principle is at the heart of a good part of fundamental physics: Starting with a group G of so-called rigid symmetries of a functional defined over space-time Sigma, the original functional is extended appropriately by additional Lie(G)-valued 1-form gauge fields so as to lift the symmetry to Maps(Sigma,G). Physically relevant quantities are then to be obtained as the quotient of the solutions to the Euler-Lagrange equations by these gauge symmetries. In this article we show that one can construct a gauge theory for a standard sigma model in arbitrary space-time dimensions where the target metric is not invariant with respect to any rigid symmetry group, but satisfies a much weaker condition: It is sufficient to find a collection of vector fields v_a on the target M satisfying the extended Killing equation v_{a(i;j)}=0 for some connection acting on the index a. For regular foliations this is equivalent to merely requiring the distribution orthogonal to the leaves to be invariant with respect to leaf...
Gauging without initial symmetry
Kotov, Alexei; Strobl, Thomas
2016-01-01
The gauge principle is at the heart of a good part of fundamental physics: Starting with a group G of so-called rigid symmetries of a functional defined over space-time Σ, the original functional is extended appropriately by additional Lie(G) -valued 1-form gauge fields so as to lift the symmetry to Maps(Σ , G) . Physically relevant quantities are then to be obtained as the quotient of the solutions to the Euler-Lagrange equations by these gauge symmetries. In this article we show that one can construct a gauge theory for a standard sigma model in arbitrary space-time dimensions where the target metric is not invariant with respect to any rigid symmetry group, but satisfies a much weaker condition: It is sufficient to find a collection of vector fields va on the target M satisfying the extended Killing equationv a(i ; j) = 0 for some connection acting on the index a. For regular foliations this is equivalent to requiring the conormal bundle to the leaves with its induced metric to be invariant under leaf-preserving diffeomorphisms of M, which in turn generalizes Riemannian submersions to which the notion reduces for smooth leaf spaces M / ∼. The resulting gauge theory has the usual quotient effect with respect to the original ungauged theory: in this way, much more general orbits can be factored out than usually considered. In some cases these are orbits that do not correspond to an initial symmetry, but still can be generated by a finite-dimensional Lie group G. Then the presented gauging procedure leads to an ordinary gauge theory with Lie algebra valued 1-form gauge fields, but showing an unconventional transformation law. In general, however, one finds that the notion of an ordinary structural Lie group is too restrictive and should be replaced by the much more general notion of a structural Lie groupoid.
On Symmetries in Optimal Control
van der Schaft, A. J.
1986-01-01
We discuss the use of symmetries in solving optimal control problems. In particular a procedure for obtaining symmetries is given which can be performed before the actual calculation of the optimal control and optimal Hamiltonian.
Dynamical symmetry and shape coexistence
International Nuclear Information System (INIS)
A general discussion is given of extending the Fermion Dynamical Symmetry Model to describe shape coexistence. The theory is applied to the description of superdeformation and normal deformations through alternative dynamical symmetries
Discrete Symmetries CP, T, CPT
Bernabeu, J
2016-01-01
The role of Symmetry Breaking mechanisms to search for New Physics is of highest importance. We discuss the status and prospects of the Discrete Symmetries CP, T, CPT looking for their separate Violation in LHC experiments and meson factories.
Symmetry and topology in evolution
International Nuclear Information System (INIS)
This volume contains papers of an interdisciplinary symposium on evolution. The aim of this symposium, held in Budapest, Hungary, 28-29 May 1991, was to clear the role of symmetry and topology at different levels of the evolutionary processes. 21 papers were presented, their topics included evolution of the Universe, symmetry of elementary particles, asymmetry of the Earth, symmetry and asymmetry of biomolecules, symmetry and topology of lining objects, human asymmetry etc. (R.P.)
Concurrent symmetries: the interplay between local and global molecular symmetries.
Echeverría, Jorge; Carreras, Abel; Casanova, David; Alemany, Pere; Alvarez, Santiago
2011-01-01
We analyze in this article the degree to which different groups of atoms retain local symmetries when assembled in a molecule. This study is carried out by applying continuous symmetry measures to several families of mixed sandwiches, a variety of piano-stool molecules, and several organic groups. An analysis of the local symmetry of the electron density shows that, sandwiched between two regions of different symmetry that correspond to the ligand sets, its symmetry is cylindrical at the central metal atom. PMID:21207632
Charge independence and charge symmetry
Miller, G A; Miller, Gerald A; van Oers, Willem T H
1994-01-01
Charge independence and charge symmetry are approximate symmetries of nature, violated by the perturbing effects of the mass difference between up and down quarks and by electromagnetic interactions. The observations of the symmetry breaking effects in nuclear and particle physics and the implications of those effects are reviewed.
Dynamical Symmetries in Classical Mechanics
Boozer, A. D.
2012-01-01
We show how symmetries of a classical dynamical system can be described in terms of operators that act on the state space for the system. We illustrate our results by considering a number of possible symmetries that a classical dynamical system might have, and for each symmetry we give examples of dynamical systems that do and do not possess that…
Charge independence and charge symmetry
International Nuclear Information System (INIS)
Charge independence and charge symmetry are approximate symmetries of nature, violated by the perturbing effects of the mass difference between up and down quarks and by electromagnetic interactions. The observations of the symmetry breaking effects in nuclear and particle physics and the implications of those effects are reviewed. (author). 145 refs., 3 tabs., 11 figs
The Geometry of Noncommutative Symmetries
International Nuclear Information System (INIS)
We discuss the notion of noncommutative symmetries based on Hopf algebras in the geometric models constructed within the framework of non-commutative geometry. We introduce and discuss several notions of non-commutative symmetries and outline the construction specific examples, for instance, finite algebras and the application of symmetries in the derivation of the Dirac operator for the noncommutative torus. (author)
Emergence of Symmetries from Entanglement
CERN. Geneva
2016-01-01
Maximal Entanglement appears to be a key ingredient for the emergence of symmetries. We first illustrate this phenomenon using two examples: the emergence of conformal symmetry in condensed matter systems and the relation of tensor networks to holography. We further present a Principle of Maximal Entanglement that seems to dictate to a large extend the structure of gauge symmetry.
Asymmetry, Symmetry and Beauty
Directory of Open Access Journals (Sweden)
Abbe R. Kopra
2010-07-01
Full Text Available Asymmetry and symmetry coexist in natural and human processes. The vital role of symmetry in art has been well demonstrated. This article highlights the complementary role of asymmetry. Further we show that the interaction of asymmetric action (recursion and symmetric opposition (sinusoidal waves are instrumental in generating creative features (relatively low entropy, temporal complexity, novelty (less recurrence in the data than in randomized copies and complex frequency composition. These features define Bios, a pattern found in musical compositions and in poetry, except for recurrence instead of novelty. Bios is a common pattern in many natural and human processes (quantum processes, the expansion of the universe, gravitational waves, cosmic microwave background radiation, DNA, physiological processes, animal and human populations, and economic time series. The reduction in entropy is significant, as it reveals creativity and contradicts the standard claim of unavoidable decay towards disorder. Artistic creations capture fundamental features of the world.
Conformal symmetries of spacetimes
International Nuclear Information System (INIS)
In this paper, we give a unified and global new approach to the study of the conformal structure of the three classical Riemannian spaces as well as of the six relativistic and non-relativistic spacetimes (Minkowskian, de Sitter, anti-de Sitter, and both Newton-Hooke and Galilean). We obtain general expressions within a Cayley-Klein framework, holding simultaneously for all these nine spaces, whose cycles (including geodesics and circles) are explicitly characterized in a new way. The corresponding cycle-preserving symmetries, which give rise to (Moebius-like) conformal Lie algebras, together with their differential realizations are then deduced without having to resort to solving the conformal Killing equations. We show that each set of three spaces with the same signature type and any curvature have isomorphic conformal algebras; these are related through an apparently new conformal duality. Laplace and wave-type differential equations with conformal algebra symmetry are finally constructed. (author)
A broken symmetry ontology: Quantum mechanics as a broken symmetry
International Nuclear Information System (INIS)
The author proposes a new broken symmetry ontology to be used to analyze the quantum domain. This ontology is motivated and grounded in a critical epistemological analysis, and an analysis of the basic role of symmetry in physics. Concurrently, he is led to consider nonheterogeneous systems, whose logical state space contains equivalence relations not associated with the causal relation. This allows him to find a generalized principle of symmetry and a generalized symmetry-conservation formalisms. In particular, he clarifies the role of Noether's theorem in field theory. He shows how a broken symmetry ontology already operates in a description of the weak interactions. Finally, by showing how a broken symmetry ontology operates in the quantum domain, he accounts for the interpretational problem and the essential incompleteness of quantum mechanics. He proposes that the broken symmetry underlying this ontological domain is broken dilation invariance
Energy Technology Data Exchange (ETDEWEB)
Herrero, O F, E-mail: o.f.herrero@hotmail.co [Conservatorio Superior de Musica ' Eduardo Martinez Torner' Corrada del Obispo s/n 33003 - Oviedo - Asturias (Spain)
2010-06-01
Music and Physics are very close because of the symmetry that appears in music. A periodic wave is what music really is, and there is a field of Physics devoted to waves researching. The different musical scales are the base of all kind of music. This article tries to show how this musical scales are made, how the consonance is the base of many of them and how symmetric they are.
Cluster Symmetries and Dynamics
Directory of Open Access Journals (Sweden)
Freer Martin
2016-01-01
Full Text Available Many light nuclei display behaviour that indicates that rather than behaving as an A-body systems, the protons and neutrons condense into clusters. The α-particle is the most obvious example of such clustering. This contribution examines the role of such α-clustering on the structure, symmetries and dynamics of the nuclei 8Be, 12C and 16O, recent experimental measurements and future perspectives.
Fabella, Raul V.
1997-01-01
We consider teams where information asymmetry (adverse selection and moral hazard) is minimized by entry point screening designed to produce homogenous membership and work group arrangements and job rotation that render effort at worst imperfectly observable. We show that under membership symmetry, budget balance and strict rationality, a self-enforcing Pareto efficient (cooperates) and envy-free solution is attainable if and only production technology is of a unique concave family. Even in t...
Dynamical Electroweak Symmetry Breaking
Czech Academy of Sciences Publication Activity Database
Hošek, Jiří; Smetana, Adam
Berlin: Springer, 2014, s. 17-28. ISBN 978-3-319-07072-8 R&D Projects: GA ČR GA202/06/0734; GA MŠk LA08015; GA MŠk LA08032 Institutional support: RVO:61389005 Keywords : dynamical electroweak symmetry breaking * top-quark condensation * neutriono condensation * strong Yukawa dynamics * flavor gauge dynamics Subject RIV: BE - Theoretical Physics
International Nuclear Information System (INIS)
Music and Physics are very close because of the symmetry that appears in music. A periodic wave is what music really is, and there is a field of Physics devoted to waves researching. The different musical scales are the base of all kind of music. This article tries to show how this musical scales are made, how the consonance is the base of many of them and how symmetric they are.
Christodoulides, Demetrios
2015-03-01
Interest in complex Hamiltonians has been rekindled after the realization that a wide class of non-Hermitian Hamiltonians can have entirely real spectra as long as they simultaneously respect parity and time reversal operators. In non-relativistic quantum mechanics, governed by the Schrödinger equation, a necessary but not sufficient condition for PT symmetry to hold is that the complex potential should involve real and imaginary parts which are even and odd functions of position respectively. As recently indicated, optics provides a fertile ground to observe and utilize notions of PT symmetry. In optics, the refractive index and gain/loss profiles play the role of the real and imaginary parts of the aforementioned complex potentials. As it has been demonstrated in several studies, PT-symmetric optical structures can exhibit peculiar properties that are otherwise unattainable in traditional Hermitian (conservative) optical settings. Among them, is the possibility for breaking this symmetry through an abrupt phase transition, band merging effects and unidirectional invisibility. Here we review recent developments in the field of -symmetric optics.
International Nuclear Information System (INIS)
This new edition of Prof. Strocchi's well received primer on rigorous aspects of symmetry breaking presents a more detailed and thorough discussion of the mechanism of symmetry breaking in classical field theory in relation with the Noether theorem. Moreover, the link between symmetry breaking without massless Goldstone bosons in Coulomb systems and in gauge theories is made more explicit in terms of the delocalized Coulomb dynamics. Furthermore, the chapter on the Higgs mechanism has been significantly expanded with a non-perturbative treatment of the Higgs phenomenon, at the basis of the standard model of particle physics, in the local and in the Coulomb gauges. Last but not least, a subject index has been added and a number of misprints have been corrected. From the reviews of the first edition: The notion of spontaneous symmetry breaking has proven extremely valuable, the problem is that most derivations are perturbative and heuristic. Yet mathematically precise versions do exist, but are not widely known. It is precisely the aim of his book to correct this unbalance. - It is remarkable to see how much material can actually be presented in a rigorous way (incidentally, many of the results presented are due to Strocchi himself), yet this is largely ignored, the original heuristic derivations being, as a rule, more popular. - At each step he strongly emphasizes the physical meaning and motivation of the various notions introduced, a book that fills a conspicuous gap in the literature, and does it rather well. It could also be a good basis for a graduate course in mathematical physics. It can be recommended to physicists as well and, of course, for physics/mathematics libraries. J.-P. Antoine, Physicalia 28/2, 2006 Strocchi's main emphasis is on the fact that the loss of symmetric behaviour requires both the non-symmetric ground states and the infinite extension of the system. It is written in a pleasant style at a level suitable for graduate students in
Directory of Open Access Journals (Sweden)
Vladan Nikolić
2015-02-01
Full Text Available The idea of construction of twin buildings is as old as architecture itself, and yet there is hardly any study emphasizing their specificity. Most frequently there are two objects or elements in an architectural composition of “twins” in which there may be various symmetry relations, mostly bilateral symmetries. The classification of “twins” symmetry in this paper is based on the existence of bilateral symmetry, in terms of the perception of an observer. The classification includes both, 2D and 3D perception analyses. We start analyzing a pair of twin buildings with projection of the architectural composition elements in 2D picture plane (plane of the composition and we distinguish four 2D keyframe cases based on the relation between the bilateral symmetry of the twin composition and the bilateral symmetry of each element. In 3D perception for each 2D keyframe case there are two sub-variants, with and without a symmetry plane parallel to the picture plane. The bilateral symmetry is dominant if the corresponding symmetry plane is orthogonal to the picture plane. The essence of the complete classification is relation between the bilateral (dominant symmetry of the architectural composition and the bilateral symmetry of each element of that composition.
Rotational-isotopic symmetries
International Nuclear Information System (INIS)
In this note we submit a nonlocal (integral) generalization of the rotational-isotopic symmetries O-circumflex(3) introduced in preceding works for nonlinear and nonhamiltonian systems in local approximation. By recalling that the Lie-isotopic theory naturally admits nonlocal terms when all embedded in the isounit, while the conventional symplectic geometry is strictly local-differential, we introduce the notion of symplectic-isotopic two-forms, which are exact symplectic two-forms admitting a factorization into the Kronecker product of a canonical two-form time the isotopic element of an underlying Euclidean-isotopic space. Topological consistency is then achieved by embedding all nonlocal terms in the isounit of the iso-cotangent bundle, while keeping the local topology for the canonical part. In this way, we identify the symplectic-isotopic geometry as being the natural geometrical counterpart of the Lie-isotopic theory. The results are used for the introduction of the notion of Birkhoffian angular momentum, that is, the generalization of the conventional canonical angular momentum which is applicable to Birkhoffian systems with generally nonlinear, nonlocal and nonhamiltonian internal forces. The generators J (and the parameters θ) coincide with the conventional quantities. Nevertheless, the quantity J is defined on the underlying Euclidean-isotopic space, by therefore acquiring a generalized magnitude. The isocommutation rules and isoexponentiation of the Birkhoffian angular momentum are explicitly computed and shown to characterize the most general known nonlinear and nonlocal realization of the isorotational symmetry. The local isomorphisms between the infinitely possible isotopes O-circumflex(3) and the conventional symmetry O(3) is proved. Finally the isosymmetries O-circumflex(3) are used to characterize the conserved, total, Birkhoffian angular momentum of closed nonselfadjoint systems. (author). 4 refs
Yale, Paul B
2012-01-01
This book is an introduction to the geometry of Euclidean, affine, and projective spaces with special emphasis on the important groups of symmetries of these spaces. The two major objectives of the text are to introduce the main ideas of affine and projective spaces and to develop facility in handling transformations and groups of transformations. Since there are many good texts on affine and projective planes, the author has concentrated on the n-dimensional cases.Designed to be used in advanced undergraduate mathematics or physics courses, the book focuses on ""practical geometry,"" emphasi
Conformal Symmetry and Unification
Pawlowski, M
1998-01-01
The Weyl-Weinberg-Salam model is presented. It is based on the local conformal gauge symmetry. The model identifies the Higgs scalar field in SM with the Penrose-Chernikov-Tagirov scalar field of the conformal theory of gravity. Higgs mechanism for generation of particle masses is replaced by the originated in Weyl's ideas conformal gauge scale fixing. Scalar field is no longer a dynamical field of the model and does not lead to quantum particle-like excitations that could be observed in HE experiments. Cosmological constant is naturally generated by the scalar quadric term. The model admits Weyl vector bosons that can mix with photon and weak bosons.
Baldo, M.; Burgio, G.F.
2016-01-01
The nuclear symmetry energy characterizes the variation of the binding energy as the neutron to proton ratio of a nuclear system is varied. This is one of the most important features of nuclear physics in general, since it is just related to the two component nature of the nuclear systems. As such it is one of the most relevant physical parameters that affect the physics of many phenomena and nuclear processes. This review paper presents a survey of the role and relevance of the nuclear symme...
Rosensteel, George
1995-01-01
Riemann ellipsoids model rotating galaxies when the galactic velocity field is a linear function of the Cartesian coordinates of the galactic masses. In nuclear physics, the kinetic energy in the linear velocity field approximation is known as the collective kinetic energy. But, the linear approximation neglects intrinsic degrees of freedom associated with nonlinear velocity fields. To remove this limitation, the theory of symplectic dynamical symmetry is developed for classical systems. A classical phase space for a self-gravitating symplectic system is a co-adjoint orbit of the noncompact group SP(3,R). The degenerate co-adjoint orbit is the 12 dimensional homogeneous space Sp(3,R)/U(3), where the maximal compact subgroup U(3) is the symmetry group of the harmonic oscillator. The Hamiltonian equations of motion on each orbit form a Lax system X = (X,F), where X and F are elements of the symplectic Lie algebra. The elements of the matrix X are the generators of the symplectic Lie algebra, viz., the one-body collective quadratic functions of the positions and momenta of the galactic masses. The matrix F is composed from the self-gravitating potential energy, the angular velocity, and the hydostatic pressure. Solutions to the hamiltonian dynamical system on Sp(3,R)/U(3) are given by symplectic isospectral deformations. The Casimirs of Sp(3,R), equal to the traces of powers of X, are conserved quantities.
Energy Technology Data Exchange (ETDEWEB)
Kubo, Jisuke [Kanazawa Univ., Inst. for Theoretical Physics, Kanazawa (Japan); Mondragon, Alfonso; Mondragon, Myriam; Rodriguez-jauregui, Ezequiel [UNAM, Instituto de Fisica, Mexico (Mexico)
2003-05-01
Assuming that the lepton, quark and Higgs fields belong to the three-dimensional reducible representation of the permutation group S{sub 3}, we suggest a minimal S{sub 3} invariant extension of the standard model. We find that in the leptonic sector, the exact S{sub 3} x Z{sub 2} symmetry, which allows 6 real independent parameters, is consistent with experimental data and predicts the bi-maximal mixing of the left-handed neutrinos and that the third neutrino is the lightest neutrino. Z{sub 2} is anomaly-free, but it forbids CP-violations in the leptonic, as well as in the hadronic sector. Therefore, the origin of CP-violations can be identified with the breaking of the Z{sub 2} symmetry, which may be understood in a more fundamental theory. With the exact S{sub 3} only, there are 10 real independent parameters and one independent phase, on which the Cabibbo-Kobayashi-Maskawa mixing matrix V{sub CKM} depends. A set of values of these parameters that are consistent with experimental observations is given. (author)
International Nuclear Information System (INIS)
Assuming that the lepton, quark and Higgs fields belong to the three-dimensional reducible representation of the permutation group S3, we suggest a minimal S3 invariant extension of the standard model. We find that in the leptonic sector, the exact S3 x Z2 symmetry, which allows 6 real independent parameters, is consistent with experimental data and predicts the bi-maximal mixing of the left-handed neutrinos and that the third neutrino is the lightest neutrino. Z2 is anomaly-free, but it forbids CP-violations in the leptonic, as well as in the hadronic sector. Therefore, the origin of CP-violations can be identified with the breaking of the Z2 symmetry, which may be understood in a more fundamental theory. With the exact S3 only, there are 10 real independent parameters and one independent phase, on which the Cabibbo-Kobayashi-Maskawa mixing matrix VCKM depends. A set of values of these parameters that are consistent with experimental observations is given. (author)
Kubo, J; Mondragón, M N; Rodríguez-Jáuregui, E
2003-01-01
Assuming that the lepton, quark and Higgs fields belong to the three-dimensional reducible representation of the permutation group S_3, we suggest a minimal S_3 invariant extension of the standard model. We find that in the leptonic sector the exact S_3 X Z_2 symmetry, which allows 6 real independent parameters, is consistent with experimental data and predicts the bi-maximal mixing of the left-handed neutrinos and that the $tau$ neutrino is the lightest neutrinno. Z_2 is anomaly-free, but forbids CP-violations in the leptonic as well as in the hadronic sector. Therefore, we may identify the origin of the CP-violations with the breaking of the Z_2 symmetry, which may be understood in a more fundamental theory. With the exact S_3 only, there are 10 real independent parameters and one independent phase in the hadronic sector. A set of the values of these parameters that are consistent with the experimental observations is given.
Applications of chiral symmetry
International Nuclear Information System (INIS)
The author discusses several topics in the applications of chiral symmetry at nonzero temperature. First, where does the rho go? The answer: up. The restoration of chiral symmetry at a temperature Tχ implies that the ρ and a1 vector mesons are degenerate in mass. In a gauged linear sigma model the ρ mass increases with temperature, mρ(Tχ) > mρ(0). The author conjectures that at Tχ the thermal ρ - a1, peak is relatively high, at about ∼1 GeV, with a width approximately that at zero temperature (up to standard kinematic factors). The ω meson also increases in mass, nearly degenerate with the ρ, but its width grows dramatically with temperature, increasing to at least ∼100 MeV by Tχ. The author also stresses how utterly remarkable the principle of vector meson dominance is, when viewed from the modern perspective of the renormalization group. Secondly, he discusses the possible appearance of disoriented chiral condensates from open-quotes quenchedclose quotes heavy ion collisions. It appears difficult to obtain large domains of disoriented chiral condensates in the standard two flavor model. This leads to the last topic, which is the phase diagram for QCD with three flavors, and its proximity to the chiral critical point. QCD may be very near this chiral critical point, and one might thereby generated large domains of disoriented chiral condensates
Bootstrap Dynamical Symmetry Breaking
Directory of Open Access Journals (Sweden)
Wei-Shu Hou
2013-01-01
Full Text Available Despite the emergence of a 125 GeV Higgs-like particle at the LHC, we explore the possibility of dynamical electroweak symmetry breaking by strong Yukawa coupling of very heavy new chiral quarks Q . Taking the 125 GeV object to be a dilaton with suppressed couplings, we note that the Goldstone bosons G exist as longitudinal modes V L of the weak bosons and would couple to Q with Yukawa coupling λ Q . With m Q ≳ 700 GeV from LHC, the strong λ Q ≳ 4 could lead to deeply bound Q Q ¯ states. We postulate that the leading “collapsed state,” the color-singlet (heavy isotriplet, pseudoscalar Q Q ¯ meson π 1 , is G itself, and a gap equation without Higgs is constructed. Dynamical symmetry breaking is affected via strong λ Q , generating m Q while self-consistently justifying treating G as massless in the loop, hence, “bootstrap,” Solving such a gap equation, we find that m Q should be several TeV, or λ Q ≳ 4 π , and would become much heavier if there is a light Higgs boson. For such heavy chiral quarks, we find analogy with the π − N system, by which we conjecture the possible annihilation phenomena of Q Q ¯ → n V L with high multiplicity, the search of which might be aided by Yukawa-bound Q Q ¯ resonances.
Directory of Open Access Journals (Sweden)
Angel Garrido
2011-01-01
Full Text Available In this paper, we analyze a few interrelated concepts about graphs, such as their degree, entropy, or their symmetry/asymmetry levels. These concepts prove useful in the study of different types of Systems, and particularly, in the analysis of Complex Networks. A System can be defined as any set of components functioning together as a whole. A systemic point of view allows us to isolate a part of the world, and so, we can focus on those aspects that interact more closely than others. Network Science analyzes the interconnections among diverse networks from different domains: physics, engineering, biology, semantics, and so on. Current developments in the quantitative analysis of Complex Networks, based on graph theory, have been rapidly translated to studies of brain network organization. The brain's systems have complex network features—such as the small-world topology, highly connected hubs and modularity. These networks are not random. The topology of many different networks shows striking similarities, such as the scale-free structure, with the degree distribution following a Power Law. How can very different systems have the same underlying topological features? Modeling and characterizing these networks, looking for their governing laws, are the current lines of research. So, we will dedicate this Special Issue paper to show measures of symmetry in Complex Networks, and highlight their close relation with measures of information and entropy.
SYMMETRY IN WORLD TRADE NETWORK
Institute of Scientific and Technical Information of China (English)
Hui WANG; Guangle YAN; Yanghua XIAO
2009-01-01
Symmetry of the world trade network provides a novel perspective to understand the world-wide trading system. However, symmetry in the world trade network (WTN) has been rarely studied so far. In this paper, the authors systematically explore the symmetry in WTN. The authors construct WTN in 2005 and explore the size and structure of its automorphism group, through which the authors find that WTN is symmetric, particularly, locally symmetric to a certain degree. Furthermore, the authors work out the symmetric motifs of WTN and investigate the structure and function of the symmetric motifs, coming to the conclusion that local symmetry will have great effect on the stability of the WTN and that continuous symmetry-breakings will generate complexity and diversity of the trade network. Finally, utilizing the local symmetry of the network, the authors work out the quotient of WTN, which is the structural skeleton dominating stability and evolution of WTN.
Symmetry of crystals and molecules
Ladd, Mark
2014-01-01
This book successfully combines a thorough treatment of molecular and crystalline symmetry with a simple and informal writing style. By means of familiar examples the author helps to provide the reader with those conceptual tools necessary for the development of a clear understanding of what are often regarded as 'difficult' topics. Christopher Hammond, University of Leeds This book should tell you everything you need to know about crystal and molecular symmetry. Ladd adopts an integrated approach so that the relationships between crystal symmetry, molecular symmetry and features of chemical interest are maintained and reinforced. The theoretical aspects of bonding and symmetry are also well represented, as are symmetry-dependent physical properties and the applications of group theory. The comprehensive coverage will make this book a valuable resource for a broad range of readers.
Wilczek, Frank
2004-01-01
Powerful symmetry principles have guided physicists in their quest for nature's fundamental laws. The successful gauge theory of electroweak interactions postulates a more extensive symmetry for its equations than are manifest in the world (8 pages) Powerful symmetry principles have guided physicists in their quest for nature's fundamental laws. The successful gauge theory of electroweak interactions postulates a more extensive symmetry for its equations than are manifest in the world. The discrepancy is ascribed to a pervasive symmetry-breaking field, which fills all space uniformly, rendering the Universe a sort of exotic superconductor. So far, the evidence for these bold ideas is indirect. But soon the theory will undergo a critical test depending on whether the quanta of this symmetry-breaking field, the so-called Higgs particles, are produced at the Large Hadron Collider (due to begin operation in 2007).
Trieste lectures on mirror symmetry
International Nuclear Information System (INIS)
These are pedagogical lectures on mirror symmetry given at the Spring School in ICTP, Trieste, March 2002. The focus is placed on worldsheet descriptions of the physics related to mirror symmetry. We start with the introduction to general aspects of (2,2) supersymmetric field theories in 1 + 1 dimensions. We next move on to the study and applications of linear sigma model. Finally, we provide a proof of mirror symmetry in a class of models. (author)
Quarks, baryons and chiral symmetry
Hosaka, Atsushi
2001-01-01
This book describes baryon models constructed from quarks, mesons and chiral symmetry. The role of chiral symmetry and of quark model structure with SU(6) spin-flavor symmetry are discussed in detail, starting from a pedagogic introduction. Emphasis is placed on symmetry aspects of the theories. As an application, the chiral bag model is studied for nucleon structure, where important methods of theoretical physics, mostly related to the semiclassical approach for a system of strong interactions, are demonstrated. The text is more practical than formal; tools and ideas are explained in detail w
The conservation of orbital symmetry
Woodward, R B
2013-01-01
The Conservation of Orbital Symmetry examines the principle of conservation of orbital symmetry and its use. The central content of the principle was that reactions occur readily when there is congruence between orbital symmetry characteristics of reactants and products, and only with difficulty when that congruence does not obtain-or to put it more succinctly, orbital symmetry is conserved in concerted reaction. This principle is expected to endure, whatever the language in which it may be couched, or whatever greater precision may be developed in its application and extension. The book ope
Physical Theories with Average Symmetry
Alamino, Roberto C
2013-01-01
This Letter probes the existence of physical laws invariant only in average when subjected to some transformation. The concept of a symmetry transformation is broadened to include corruption by random noise and average symmetry is introduced by considering functions which are invariant only in average under these transformations. It is then shown that actions with average symmetry obey a modified version of Noether's Theorem with dissipative currents. The relation of this with possible violations of physical symmetries, as for instance Lorentz invariance in some quantum gravity theories, is briefly commented.
An introduction to Yangian symmetries
International Nuclear Information System (INIS)
Some aspects of the quantum Yangians as symmetry algebras of two-dimensional quantum field theories are reviewed. They include two main issues: the first is the classical Heisenberg model, covering non-Abelian symmetries, generators of the symmetries and the semi-classical Yangians, an alternative presentation of the semi-classical Yangians, digression on Poisson-Lie groups. The second is the quantum Heisenberg chain, covering non-Abelian symmetries and the quantum Yangians, the transfer matrix and an alternative presentation of the Yangians, digression on the double Yangians. (K.A.) 15 refs
Symmetries of Quantum Nonsymmetric Gravity
Mebarki, N; Boudine, A; Benslama, A
1999-01-01
Symmetries of Quantum Nonsymmetric gravity are studied and the corresponding generators are constructed . The related equal time canonical (and non canonical) (anti) commutation relations are established.
Segmentation Using Symmetry Deviation
DEFF Research Database (Denmark)
Hollensen, Christian; Højgaard, L.; Specht, L.;
2011-01-01
the 10 hypopharyngeal cancer patients to find anatomical symmetry and evaluate it against the standard deviation of the normal patients to locate pathologic volumes. Combining the information with an absolute PET threshold of 3 Standard uptake value (SUV) a volume was automatically delineated. The...... overlap of automated segmentations on manual contours was evaluated using concordance index and sensitivity for the hypopharyngeal patients. The resulting concordance index and sensitivity was compared with the result of using a threshold of 3 SUV using a paired t-test. Results: The anatomical and...... overlap concordance index and sensitivity of respectively 0.43±0.15 and 0.56±0.18 was acquired. It was compared to the concordance index of segmentation using absolute threshold of 3 SUV giving respectively 0.41±0.16 and 0.51±0.19 for concordance index and sensitivity yielding p-values of 0.33 and 0...
Lie Symmetries of Ishimori Equation
Institute of Scientific and Technical Information of China (English)
SONG Xu-Xia
2013-01-01
The Ishimori equation is one of the most important (2+1)-dimensional integrable models,which is an integrable generalization of (1+1)-dimensional classical continuous Heisenberg ferromagnetic spin equations.Based on importance of Lie symmetries in analysis of differential equations,in this paper,we derive Lie symmetries for the Ishimori equation by Hirota's direct method.
Symmetry violation in nuclear reactions
International Nuclear Information System (INIS)
Precision studies of nuclear reactions can be used to search for small violations of the discrete symmetries. Recent and proposed experimental work using nuclear reactions to study the breakdown of three symmetries - isospin (I), parity (P) and time-reversal (T) is reviewed. 44 references
Behind the shirts, is symmetry
Galam, S
1998-01-01
The outbreak of spontaneous order in matter results from symmetry breaking. How does a system change its collective organisation ? How does it break its own symmetry ? That are the questions which are answered using a metaphoric world of shirts and colors.
BRST symmetry of Unimodular Gravity
Upadhyay, S.; Oksanen, M.; Bufalo, R.
2015-01-01
We derive the BRST symmetry for two versions of unimodular gravity, namely, fully diffeomorphism-invariant unimodular gravity and unimodular gravity with fixed metric determinant. The BRST symmetry is generalized further to the finite field-dependent BRST, in order to establish the connection between different gauges in each of the two versions of unimodular gravity.
Generalized Atkin-Lehner symmetry
International Nuclear Information System (INIS)
Atkin-Lehner symmetry was proposed several years ago as a mechanism for obtaining a vanishing one-loop cosmological constant in nonsupersymmetric superstring models, but for models formulated in four-dimensional spacetime this symmetry cannot be realized. We therefore investigate various means of retaining the general Atkin-Lehner idea without having strict Atkin-Lehner symmetry. We first explicitly construct non-Atkin-Lehner-symmetric partition functions which not only lead to vanishing cosmological constants but which also avoid a recent proof that Atkin-Lehner-symmetric partition functions cannot arise from physically viable string models in greater than two dimensions. We then develop a systematic generalization of Atkin-Lehner symmetry, basing our considerations on the use of non-Hermitian operators as well as on a general class of possible congruence subgroups of the full modular group. We find that whereas in many instances our resulting symmetries reduce to either strict Atkin-Lehner symmetry or symmetries closely related to it, in other cases we obtain symmetries of a fundamentally new character. Our results therefore suggest possible new avenues for retaining the general Atkin-Lehner ''selection rule'' approach for obtaining a vanishing one-loop cosmological constant
Shape analysis with subspace symmetries
Berner, Alexander
2011-04-01
We address the problem of partial symmetry detection, i.e., the identification of building blocks a complex shape is composed of. Previous techniques identify parts that relate to each other by simple rigid mappings, similarity transforms, or, more recently, intrinsic isometries. Our approach generalizes the notion of partial symmetries to more general deformations. We introduce subspace symmetries whereby we characterize similarity by requiring the set of symmetric parts to form a low dimensional shape space. We present an algorithm to discover subspace symmetries based on detecting linearly correlated correspondences among graphs of invariant features. We evaluate our technique on various data sets. We show that for models with pronounced surface features, subspace symmetries can be found fully automatically. For complicated cases, a small amount of user input is used to resolve ambiguities. Our technique computes dense correspondences that can subsequently be used in various applications, such as model repair and denoising. © 2010 The Author(s).
Symmetry inheritance of scalar fields
Smolić, Ivica
2015-07-01
Matter fields do not necessarily have to share the symmetries with the spacetime they live in. When this happens, we speak of the symmetry inheritance of fields. In this paper we classify the obstructions of symmetry inheritance by the scalar fields, both real and complex, and look more closely at the special cases of stationary and axially symmetric spacetimes. Since the symmetry noninheritance is present in the scalar fields of boson stars and may enable the existence of the black hole scalar hair, our results narrow the possible classes of such solutions. Finally, we define and analyse the symmetry noninheritance contributions to the Komar mass and angular momentum of the black hole scalar hair.
Symmetry inheritance of scalar fields
Smolić, Ivica
2015-01-01
Matter fields don't necessarily have to share the symmetries with the spacetime they live in. When this happens, we speak of the symmetry inheritance of fields. In this paper we classify the obstructions of symmetry inheritance by the scalar fields, both real and complex, and look more closely at the special cases of stationary and axially symmetric spacetimes. Since the symmetry noninheritance is present in the scalar fields of boson stars and may enable the existence of the black hole scalar hair, our results narrow the possible classes of such solutions. Finally, we define and analyse the symmetry noninheritance contributions to Komar mass and angular momentum of the black hole scalar hair.
Asymptotic Symmetries from finite boxes
Andrade, Tomas
2015-01-01
It is natural to regulate an infinite-sized system by imposing a boundary condition at finite distance, placing the system in a "box." This breaks symmetries, though the breaking is small when the box is large. One should thus be able to obtain the asymptotic symmetries of the infinite system by studying regulated systems. We provide concrete examples in the context of Einstein-Hilbert gravity (with negative or zero cosmological constant) by showing in 4 or more dimensions how the Anti-de Sitter and Poincar\\'e asymptotic symmetries can be extracted from gravity in a spherical box with Dirichlet boundary conditions. In 2+1 dimensions we obtain the full double-Virasoro algebra of asymptotic symmetries for AdS$_3$ and, correspondingly, the full Bondi-Metzner-Sachs (BMS) algebra for asymptotically flat space. In higher dimensions, a related approach may continue to be useful for constructing a good asymptotically flat phase space with BMS asymptotic symmetries.
Asymptotic symmetries from finite boxes
Andrade, Tomás; Marolf, Donald
2016-01-01
It is natural to regulate an infinite-sized system by imposing a boundary condition at finite distance, placing the system in a 'box.' This breaks symmetries, though the breaking is small when the box is large. One should thus be able to obtain the asymptotic symmetries of the infinite system by studying regulated systems. We provide concrete examples in the context of Einstein-Hilbert gravity (with negative or zero cosmological constant) by showing in 4 or more dimensions how the anti-de Sitter and Poincaré asymptotic symmetries can be extracted from gravity in a spherical box with Dirichlet boundary conditions. In 2 + 1 dimensions we obtain the full double-Virasoro algebra of asymptotic symmetries for AdS3 and, correspondingly, the full Bondi-Metzner-Sachs (BMS) algebra for asymptotically flat space. In higher dimensions, a related approach may continue to be useful for constructing a good asymptotically flat phase space with BMS asymptotic symmetries.
Discrete symmetries in the MSSM
Energy Technology Data Exchange (ETDEWEB)
Schieren, Roland
2010-12-02
The use of discrete symmetries, especially abelian ones, in physics beyond the standard model of particle physics is discussed. A method is developed how a general, abelian, discrete symmetry can be obtained via spontaneous symmetry breaking. In addition, anomalies are treated in the path integral approach with special attention to anomaly cancellation via the Green-Schwarz mechanism. All this is applied to the minimal supersymmetric standard model. A unique Z{sup R}{sub 4} symmetry is discovered which solves the {mu}-problem as well as problems with proton decay and allows to embed the standard model gauge group into a simple group, i.e. the Z{sup R}{sub 4} is compatible with grand unification. Also the flavor problem in the context of minimal flavor violation is addressed. Finally, a string theory model is presented which exhibits the mentioned Z{sup R}{sub 4} symmetry and other desirable features. (orig.)
UV completion without symmetry restoration
Endlich, Solomon; Penco, Riccardo
2013-01-01
We show that it is not possible to UV-complete certain low-energy effective theories with spontaneously broken space-time symmetries by embedding them into linear sigma models, that is, by adding "radial" modes and restoring the broken symmetries. When such a UV completion is not possible, one can still raise the cutoff up to arbitrarily higher energies by adding fields that transform non-linearly under the broken symmetries, that is, new Goldstone bosons. However, this (partial) UV completion does not necessarily restore any of the broken symmetries. We illustrate this point by considering a concrete example in which a combination of space-time and internal symmetries is broken down to a diagonal subgroup. Along the way, we clarify a recently proposed interpretation of inverse Higgs constraints as gauge-fixing conditions.
Mei Symmetry and Lie Symmetry of the Rotational Relativistic Variable Mass System
Institute of Scientific and Technical Information of China (English)
FANGJian-Hui
2003-01-01
The Mei symmetry and the Lie symmetry of a rotational relativistic variable mass system are studied. The definitions and criteria of the Mei symmetry and the Lie symmetry of the rotational relativistic variable mass system are given. The relation between the Mei symmetry and the Lie symmetry is found. The conserved quantities which the Mei symmetry and the Lie symmetry lead to are obtained. An example is given to illustrate the application of the result.
Symmetries in nuclear structure
Allaart, K; Dieperink, A
1983-01-01
The 1982 summer school on nuclear physics, organized by the Nuclear Physics Division of the Netherlands' Physical Society, was the fifth in a series that started in 1963. The number of students attending has always been about one hundred, coming from about thirty countries. The theme of this year's school was symmetry in nuclear physics. This book covers the material presented by the enthusi astic speakers, who were invited to lecture on this subject. We think they have succeeded in presenting us with clear and thorough introductory talks at graduate or higher level. The time schedule of the school and the location allowed the participants to make many informal contacts during many social activities, ranging from billiards to surf board sailing. We hope and expect that the combination of a relaxed atmosphere during part of the time and hard work during most of the time, has furthered the interest in, and understanding of, nuclear physics. The organization of the summer school was made possible by substantia...
Gravitation and Gauge Symmetries
Stewart, J
2002-01-01
The purpose of this book (I quote verbatim from the back cover) is to 'shed light upon the intrinsic structure of gravity and the principle of gauge invariance, which may lead to a consistent unified field theory', a very laudable aim. The content divides fairly clearly into four sections (and origins). After a brief introduction, chapters 2-6 review the 'Structure of gravity as a theory based on spacetime gauge symmetries'. This is fairly straightforward material, apparently based on a one-semester graduate course taught at the University of Belgrade for about two decades, and, by implication, this is a reasonably accurate description of its level and assumed knowledge. There follow two chapters of new material entitled 'Gravity in flat spacetime' and 'Nonlinear effects in gravity'. The final three chapters, entitled 'Supersymmetry and supergravity', 'Kaluza-Klein theory' and 'String theory' have been used for the basis of a one-semester graduate course on the unification of fundamental interactions. The boo...
International Nuclear Information System (INIS)
The suggestion by Jaffe that if σ is a light q2q-bar2 state 0++ then even the fundamental chiral transformation properties of the σ becomes unclear, has stimulated much interest. Adler pointed out that in fact the seminal work on chiral symmetry via PCAC consistency, is really quite consistent with the σ being predominantly q2q-bar2. This interpretation was actually backed by subsequent work on effective Lagrangian methods for linear and non linear realizations. More recent work of Achasov suggests that intermediate four-quark states determine amplitudes involving other scalars a0(980) and f0(980) below 1 GeV, and the report by Ning Wu that study on σ meson in J/ψ → ωπ+π- continue to support a non qq-bar σ with mass as low as 390 MeV. It is also noted that more recent re-analysis of πK scattering by S. Ishida et al. together with the work of the E791 Collaboration, support the existence of the scalar κ particle with comparatively light mass as well
On Discrete Gauge Symmetries in Trinification Model
Laamara, R Ahl; Ennadifi, S -E; Nassiri, S
2016-01-01
Given the important role of discrete gauge symmetries in viable models, we discuss these symmetries in intersecting D6-brane trinification model where the ZN symmetry is investigated and its identification is shown.
Symmetry protected single photon subradiance
Cai, Han; Svidzinsky, Anatoly A; Zhu, Shi-Yao; Scully, Marlan O
2016-01-01
We study the protection of subradiant states by the symmetry of the atomic distributions in the Dicke limit, in which collective Lamb shift cannot be neglected. We find that anti-symmetric states are subradiant states for distribution with reflection symmetry. These states can be prepared by anti-symmetric optical modes and converted to superradiant states by properly tailored 2\\pipulses. Continuous symmetry can also be used to achieve subradiance. This study is relevant to the problem of robust quantum memory with long storage time and fast readout.
$PT$ Symmetry, Conformal Symmetry, and the Metrication of Electromagnetism
Mannheim, Philip D.
2014-01-01
We present some interesting connections between $PT$ symmetry and conformal symmetry. We use them to develop a metricated theory of electromagnetism in which the electromagnetic field is present in the geometric connection. However, unlike Weyl who first advanced this possibility, we do not take the connection to be real but to instead be $PT$ symmetric, with it being $iA_{\\mu}$ rather than $A_{\\mu}$ itself that then appears in the connection. With this modification the standard minimal coupl...
OPTICAL METAMATERIALS WITH QUASICRYSTALLINE SYMMETRY: SYMMETRY-INDUCED OPTICAL ISOTROPY
Kruk, Sergey S.; Decker, Manuel; Helgert, Christian
2013-01-01
We compare, both experimentally and theoretically, metamaterials with three different symmetries: square lattice, hexagonal lattice, and quasicrystalline Penrose tiling. By relying on an advanced Jones calculus, we link the symmetry properties to the farfield optical response, such as ellipticity and circular dichroism, as the incident angle is varied. We show that hexagonal lattice metamaterials, when compared to the square ones, exhibit less circular dichroism and ellipticity due t...
Symmetry violations in subatomic physics
International Nuclear Information System (INIS)
This book presents papers on chiral symmetry, phase transitions, QCD lattices and sum rules, QCD reactions and deep inelastic processes, and electroweak interactions. The papers include gluon interactions and proton scattering and the chiral bag model with vector mesons
Kohn's theorem and Galilean symmetry
Zhang, P-M
2011-01-01
The relation between the separability of a system of charged particles in a uniform magnetic field and Galilean symmetry is revisited using Duval's "Bargmann framework". If the charge-to-mass ratios of the particles are identical, $e_a/m_a=\\epsilon$ for all particles, then the Bargmann space of the magnetic system is isometric to that of an anisotropic harmonic oscillator. Assuming that the particles interact through a potential which only depends on their relative distances, the system splits into one representing the center of mass plus a decoupled internal part, and can be mapped further into an isolated system using Niederer's transformation. Conversely, the manifest Galilean boost symmetry of the isolated system can be "imported" to the oscillator and to the magnetic systems, respectively, to yield the symmetry used by Gibbons and Pope to prove the separability. For vanishing interaction potential the isolated system is free and our procedure endows all our systems with a hidden Schroedinger symmetry, au...
Relativistic Symmetry and Entangled Correlations
Kellman, M E
2002-01-01
It is argued that the standard quantum mechanical description of the Bell correlations between entangled subsystems is in conflict with relativistic space-time symmetry. Proposals to abandon relativistic symmetry, in the sense of explicitly returning to an absolute time and preferred frame, are rejected on the grounds that the preferred frame is not empirically detectable, so the asymmetry is an unsatisfactory feature in physical theory. A "symmetric view" is proposed in which measurement events on space-like separated entangled subsystems are connected by a symmetric two-way mutual influence. Because of this reciprocity, there is complete symmetry of the description: Einsteinian relativity of simultaneity and space-time symmetry are completely preserved. The nature of the two-way influence is considered, as well as the possibility of an empirical test.
External symmetry in general relativity
International Nuclear Information System (INIS)
We propose a generalization of the isometry transformations to the geometric context of the spin field theories where the local frames are explicitly involved. We define the external symmetry transformations as isometries combined with suitable tetrad gauge transformations and we show that these form a group which is locally isomorphic with the isometry one. We point out that the symmetry transformations leave invariant the field equations and have generators with specific spin terms that represent new physical observables. The examples we give are the generators of the central symmetry and those of the maximal symmetries of the de Sitter and anti-de Sitter spacetimes for which we derive the spin terms in different tetrad gauge fixings. (author)
Symmetry and quaternionic integrable systems
Gaeta, G.; Rodríguez, M. A.
2015-01-01
Given a hyperkahler manifold M, the hyperkahler structure defines a triple of symplectic structures on M; with these, a triple of Hamiltonians defines a so-called hyperHamiltonian dynamical system on M. These systems are integrable when can be mapped to a system of quaternionic oscillators. We discuss the symmetry of integrable hyperHamiltonian systems, i.e. quaternionic oscillators, and conversely how these symmetries characterize, at least in the Euclidean case, integrable hyperHamiltonian systems.
Hidden Symmetries in Simple Graphs
Directory of Open Access Journals (Sweden)
Allen D. Parks
2012-03-01
Full Text Available It is shown that each element s in the normalizer of the automorphism group Aut(G of a simple graph G with labeled vertex set V is an Aut(G invariant isomorphism between G and the graph obtained from G by the s permutation of V—i.e., s is a hidden permutation symmetry of G. A simple example illustrates the theory and the applied notion of system robustness for reconfiguration under symmetry constraint (RUSC is introduced.
Conformal symmetry in quantum finance
International Nuclear Information System (INIS)
The quantum finance symmetries are studied. In order to do this, the one dimensional free non-relativistic particle and its symmetries are revisited and the particle mass is identified as the inverse of square of the volatility. Furthermore, using financial variables, a Schrödinger algebra representation is constructed. In addition, it is shown that the operators of this last representation are not hermitian and not conserved.
Dynamical symmetries in nuclear structure
International Nuclear Information System (INIS)
In recent years the concept of dynamical symmetries in nuclei has witnessed a renaissance of interest and activity. Much of this work has been developed in the context of the Interacting Boson Approximation (or IBA) model. The appearance and properties of dynamical symmetries in nuclei will be reviewed, with emphasis on their characteristic signatures and on the role of the proton-neutron interaction in their formation, systematics and evolution. 36 refs., 20 figs
Flavored Peccei-Quinn symmetry
Ahn, Y H
2014-01-01
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 se...
Mei Symmetry and Lie Symmetry of the Rotational Relativistic Variable Mass System
Institute of Scientific and Technical Information of China (English)
FANG Jian-Hui
2003-01-01
The Mei symmetry and the Lie symmetry of a rotational relativistic variable masssystem are studied. Thedefinitions and criteria of the Mei symmetry and the Lie symmetry of the rotational relativistic variable mass system aregiven. The relation between the Mei symmetry and the Lie symmetry is found. The conserved quantities which the Meisymmetry and the Lie symmetry lead to are obtained. An example is given to illustrate the application of the result.
Symmetry and symmetry breaking. Symetrie et brisure de symetrie
Energy Technology Data Exchange (ETDEWEB)
Balian, R. (CEA/Saclay, Direction des Sciences de la Matiere (DSM), 91 - Gif-sur-Yvette (France)); Lambert, D. (Facultes Universitaires Notre-Dame de la Paix, Namur (Belgium)); Brack, A. (Centre National de la Recherche Scientifique (CNRS), 45 - Orleans-la-Source (France). Centre de Biophysique Moleculaire); Englert, F. (Universite Libre de Bruxelles (Belgium). Laboratoire de Physique Theorique)
1999-01-01
The symmetry concept is a powerful tool for our understanding of the world. It allows a reduction of the volume of information needed to apprehend a subject thoroughly. Moreover this concept does not belong to a particular field, it is involved in the exact sciences but also in artistic matters. Living beings are characterized by a particular asymmetry: the chiral asymmetry. Although this asymmetry is visible in whole organisms, it seems it comes from some molecules that life always produce in one chirality. The weak interaction presents also the chiral asymmetry. The mass of particles comes from the breaking of a fundamental symmetry and the void could be defined as the medium showing as many symmetries as possible. The texts put together in this book show to a great extent how symmetry goes far beyond purely geometrical considerations. Different aspects of symmetry ideas are considered in the following fields: the states of matter, mathematics, biology, the laws of Nature, quantum physics, the universe, and the art of music. (A.C.) 103 refs.
Symmetry and symmetry breaking; Symetrie et brisure de symetrie
Energy Technology Data Exchange (ETDEWEB)
Balian, R. [CEA/Saclay, Direction des Sciences de la Matiere (DSM), 91 - Gif-sur-Yvette (France); Lambert, D. [Facultes Universitaires Notre-Dame de la Paix, Namur (Belgium); Brack, A. [Centre National de la Recherche Scientifique (CNRS), 45 - Orleans-la-Source (France). Centre de Biophysique Moleculaire; Englert, F. [Universite Libre de Bruxelles (Belgium). Laboratoire de Physique Theorique; Chomaz, Ph. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France); Lachieze-Rey, M. [CEA/Saclay, Dept. d`Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l`Instrumentation Associee (DAPNIA), 91 - Gif-sur-Yvette (France); Emery, E. [Ecole Polytechnique Federale, Lausanne (Switzerland); Cohen-Tannoudji, G.; Sacquin, Y
1999-11-01
The symmetry concept is a powerful tool for our understanding of the world. It allows a reduction of the volume of information needed to apprehend a subject thoroughly. Moreover this concept does not belong to a particular field, it is involved in the exact sciences but also in artistic matters. Living beings are characterized by a particular asymmetry: the chiral asymmetry. Although this asymmetry is visible in whole organisms, it seems it comes from some molecules that life always produce in one chirality. The weak interaction presents also the chiral asymmetry. The mass of particles comes from the breaking of a fundamental symmetry and the void could be defined as the medium showing as many symmetries as possible. The texts put together in this book show to a great extent how symmetry goes far beyond purely geometrical considerations. Different aspects of symmetry ideas are considered in the following fields: the states of matter, mathematics, biology, the laws of Nature, quantum physics, the universe, and the art of music. (A.C.) 103 refs.
Geometric aspects of some hidden symmetries
International Nuclear Information System (INIS)
Hidden symmetries of two dimensional chiral models are analysed from the geometric point of view. The dual symmetry gives rise to generalized isometries of the metric on the space of dependent variables. The Jacobi equation of geodesic deviation is dual invariant and the generalized isometries lead to generalized symmetries of the field equations. Being variational divergence symmetries they generate families of conservation laws. (orig.)
Symmetry and group theory in chemistry
Ladd, M
1998-01-01
A comprehensive discussion of group theory in the context of molecular and crystal symmetry, this book covers both point-group and space-group symmetries.Provides a comprehensive discussion of group theory in the context of molecular and crystal symmetryCovers both point-group and space-group symmetriesIncludes tutorial solutions
O'Hanlon actions by Noether symmetry
Darabi, F
2015-01-01
By using the conformal symmetry between Brans-Dicke action with $\\omega=-\\frac{3}{2}$ and O'Hanlon action, we seek the O'Hanlon actions in Einstein frame respecting the Noether symmetry. Since the Noether symmetry is preserved under conformal transformations, the existence of Noether symmetry in the Brans-Dicke action asserts the Noether symmetry in O'Hanlon action in Einstein frame. Therefore, the potentials respecting Noether symmetry in Brans-Dicke action give the corresponding potentials respecting Noether symmetry in O'Hanlon action in Einstein frame.
Novel Symmetries in Christ-Lee Model
Kumar, R
2015-01-01
We demonstrate that the gauge-fixed Lagrangian of the Christ-Lee model respects four fermionic symmetries, namely; (anti-)BRST symmetries, (anti-)co-BRST symmetries within the framework of BRST formalism. The appropriate anticommutators amongst the fermionic symmetries lead to a unique bosonic symmetry. It turn out that the algebra obeyed by the symmetry transformations (and their corresponding conserved charges) is reminiscent of the algebra satisfied by the de Rham cohomological operators of differential geometry. We also provide the physical realizations of the cohomological operators in terms of the symmetry properties.
Interfacial Fermi Loops from Interfacial Symmetries
Takahashi, Ryuji; Murakami, Shuichi
2014-01-01
We propose a concept of interfacial symmetries such as interfacial particle-hole symmetry and interfacial time-reversal symmetry, which appear in interfaces between two regions related to each other by particle-hole or time-reversal transformations. These symmetries result in novel dispersion of interface states. In particular for the interfacial particle-hole symmetry the gap closes along a loop ("Fermi loop") at the interface. We numerically demonstrate this for the Fu-Kane-Mele tight-bindi...
Miller, G A
2003-01-01
Two new experiments have detected charge-symmetry breaking, the mechanism responsible for protons and neutrons having different masses. Symmetry is a crucial concept in the theories that describe the subatomic world because it has an intimate connection with the laws of conservation. The theory of the strong interaction between quarks - quantum chromodynamics - is approximately invariant under what is called charge symmetry. In other words, if we swap an up quark for a down quark, then the strong interaction will look almost the same. This symmetry is related to the concept of sup i sospin sup , and is not the same as charge conjugation (in which a particle is replaced by its antiparticle). Charge symmetry is broken by the competition between two different effects. The first is the small difference in mass between up and down quarks, which is about 200 times less than the mass of the proton. The second is their different electric charges. The up quark has a charge of +2/3 in units of the proton charge, while ...
An Introduction to Emergent Symmetries
Gomes, Pedro R S
2015-01-01
These are intended to be introductory notes on emergent symmetries, i.e., symmetries which manifest themselves in specific sectors of energy in many systems. The emphasis is on the physical aspects rather than computation methods. We include some elementary background material and proceed to our discussion by examining several interesting problems in field theory, statistical mechanics and condensed matter. These problems illustrate how some important symmetries, such as Lorentz invariance and supersymmetry, usually believed to be fundamental, can arise naturally in low-energy regimes of systems involving a large number of degrees of freedom. The aim is to discuss how these examples could help us to face other complex and fundamental problems.
Hidden Symmetries of Stochastic Models
Directory of Open Access Journals (Sweden)
Boyka Aneva
2007-05-01
Full Text Available In the matrix product states approach to $n$ species diffusion processes the stationary probability distribution is expressed as a matrix product state with respect to a quadratic algebra determined by the dynamics of the process. The quadratic algebra defines a noncommutative space with a $SU_q(n$ quantum group action as its symmetry. Boundary processes amount to the appearance of parameter dependent linear terms in the algebraic relations and lead to a reduction of the $SU_q(n$ symmetry. We argue that the boundary operators of the asymmetric simple exclusion process generate a tridiagonal algebra whose irriducible representations are expressed in terms of the Askey-Wilson polynomials. The Askey-Wilson algebra arises as a symmetry of the boundary problem and allows to solve the model exactly.
Soft theorems from anomalous symmetries
Huang, Yu-tin
2015-01-01
We discuss constraints imposed by soft limits for effective field theories arising from symmetry breaking. In particular, we consider those associated with anomalous conformal symmetry as well as duality symmetries in supergravity. We verify these soft theorems for the dilaton effective action relevant for the a-theorem, as well as the one-loop effective action for N=4 supergravity. Using the universality of leading transcendental coefficients in the alpha' expansion of string theory amplitudes, we study the matrix elements of operator R^4 with half maximal supersymmetry. We construct the non-linear completion of R^4 that satisfies both single and double soft theorems up to seven points. This supports the existence of duality invariant completion of R^4.
Symmetry Breaking in Finite Volume
Institute of Scientific and Technical Information of China (English)
LIU Chuan
2000-01-01
Spontaneous symmetry breaking is a cooperative phenomenon for systems with infinitely many degrees of freedom and it plays an essential role in quantum field theories. Lattice O(N) model is studied within the Hamiltonian approach using an adiabatic approximation. It is shown that the low-lying spectrum of the system in the broken phase can be understood by using the adiabatic, or Born-Oppenheimer approximation, which turns out to become an expansion in the inverse power of volume. In the infinite volume limit, the symmetry is broken while in the finite volume the slow rotation of the zero-momentum mode restores the symmetry and gives rise to the rotator spectrum, which has been observed in realistic Monte Carlo simulations.
Symmetry breaking in molecular ferroelectrics.
Shi, Ping-Ping; Tang, Yuan-Yuan; Li, Peng-Fei; Liao, Wei-Qiang; Wang, Zhong-Xia; Ye, Qiong; Xiong, Ren-Gen
2016-07-11
Ferroelectrics are inseparable from symmetry breaking. Accompanying the paraelectric-to-ferroelectric phase transition, the paraelectric phase adopting one of the 32 crystallographic point groups is broken into subgroups belonging to one of the 10 ferroelectric point groups, i.e. C1, C2, C1h, C2v, C4, C4v, C3, C3v, C6 and C6v. The symmetry breaking is captured by the order parameter known as spontaneous polarization, whose switching under an external electric field results in a typical ferroelectric hysteresis loop. In addition, the responses of spontaneous polarization to other external excitations are related to a number of physical effects such as second-harmonic generation, piezoelectricity, pyroelectricity and dielectric properties. Based on these, this review summarizes recent developments in molecular ferroelectrics since 2011 and focuses on the relationship between symmetry breaking and ferroelectricity, offering ideas for exploring high-performance molecular ferroelectrics. PMID:27051889
Heisenberg symmetry and hypermultiplet manifolds
Antoniadis, Ignatios; Petropoulos, P Marios; Siampos, Konstantinos
2015-01-01
We study the emergence of Heisenberg (Bianchi II) algebra in hyper-K\\"ahler and quaternionic spaces. This is motivated by the r\\^ole these spaces with this symmetry play in $\\mathcal{N}=2$ hypermultiplet scalar manifolds. We show how to construct related pairs of hyper-K\\"ahler and quaternionic spaces under general symmetry assumptions, the former being a zooming-in limit of the latter at vanishing cosmological constant. We further apply this method for the two hyper-K\\"ahler spaces with Heisenberg algebra, which is reduced to $U(1)\\times U(1)$ at the quaternionic level. We also show that no quaternionic spaces exist with a strict Heisenberg symmetry -- as opposed to $\\text{Heisenberg} \\ltimes U(1)$. We finally discuss the realization of the latter by gauging appropriate $Sp(2,4)$ generators in $\\mathcal{N}=2$ conformal supergravity.
Symmetries in nuclei and molecules
International Nuclear Information System (INIS)
Recent progress in two different fronts is reported. First, the concept of bisection of a harmonic oscillator or hydrogen atom, used in the past in establishing the connection between U(3) and O(4), is generalized into multisection (trisection, tetra section, etc.). It is then shown that all symmetries of the N-dimensional anisotropic harmonic oscillator with rational ratios of frequencies (RHO), some of which are underlying the structure of superdeformed and hyperdeformed nuclei, can be obtained from the U(N) symmetry of the corresponding isotropic oscillator with the appropriate combination of multisections. Furthermore, it is seen that bisections of the N-dimensional hydrogen atom, which possesses an O(N+1) symmetry, lead to the U(N) symmetry, so that further multisections of the hydrogen atom lead to the symmetries of the N-dim RHO. The opposite is in general not true, i.e. multisections of U(N) do not lead to O(N+1) symmetries, the only exception being the occurrence of O(4) after the bisection of U(3). Second, it is shown that there is evidence that the recently observed in superdeformed nuclear bands δ I=4 bifurcation is also occurring in normal deformed bands of actinides and rare earths, in hyperdeformed nuclear bands, as well as in rotational bands of diatomic molecules. In addition there is evidence that a δ I=8 bifurcation, of the same order of magnitude as the δ I=4 one, is observed in superdeformed nuclear bands and rotational bands of diatomic molecules. (author)
Chiral symmetry on the lattice
International Nuclear Information System (INIS)
The author reviews some of the difficulties associated with chiral symmetry in the context of a lattice regulator. The author discusses the structure of Wilson Fermions when the hopping parameter is in the vicinity of its critical value. Here one flavor contrasts sharply with the case of more, where a residual chiral symmetry survives anomalies. The author briefly discusses the surface mode approach, the use of mirror Fermions to cancel anomalies, and finally speculates on the problems with lattice versions of the standard model
Local symmetry in random graphs
Simões, Jefferson Elbert; Figueiredo, Daniel R.; Barbosa, Valmir C.
2016-01-01
Quite often real-world networks can be thought of as being symmetric, in the abstract sense that vertices can be found to have similar or equivalent structural roles. However, traditional measures of symmetry in graphs are based on their automorphism groups, which do not account for the similarity of local structures. We introduce the concept of local symmetry, which reflects the structural equivalence of the vertices' egonets. We study the emergence of asymmetry in the Erd\\H{o}s-R\\'enyi rand...
Renormalizable models with broken symmetries
International Nuclear Information System (INIS)
The results of the renormalized perturbation theory, in the absence of massless quanta, are summarized. The global symmetry breaking is studied and the associated currents are discussed in terms of the coupling with a classical Yang Mills field. Gauge theories are discussed; it is most likely that the natural set up should be the theory of fiber bundles and that making a choice of field coordinates makes the situation obscure. An attempt is made in view of clarifying the meaning of the Slavnov symmetry which characterizes gauge field theories
Symmetry of intramolecular quantum dynamics
Burenin, Alexander V
2012-01-01
The main goal of this book is to give a systematic description of intramolecular quantum dynamics on the basis of only the symmetry principles. In this respect, the book has no analogs in the world literature. The obtained models lead to a simple, purely algebraic, scheme of calculation and are rigorous in the sense that their correctness is limited only to the correct choice of symmetry of the internal dynamics. The book is basically intended for scientists working in the field of molecular spectroscopy, quantum and structural chemistry.
Spontaneous symmetry breaking in QCD
International Nuclear Information System (INIS)
We study dynamical chiral symmetry breaking in QCD by the use of the generalized Hartree-Fock method. The low energy quark mass is calculated to the second order of diagrammatic expansion around shifted perturbative vacuum where quarks are massive. We show that the low energy mass is finite and renormalization group invariant. We find that the finite mass gap emerges as the solutions of gap equation and stationarity condition, thereby breaking the chiral symmetry. We also discuss the possibility that the breaking solution may exist up to all orders. (author)
Chiral symmetry on the lattice
Energy Technology Data Exchange (ETDEWEB)
Creutz, M.
1994-11-01
The author reviews some of the difficulties associated with chiral symmetry in the context of a lattice regulator. The author discusses the structure of Wilson Fermions when the hopping parameter is in the vicinity of its critical value. Here one flavor contrasts sharply with the case of more, where a residual chiral symmetry survives anomalies. The author briefly discusses the surface mode approach, the use of mirror Fermions to cancel anomalies, and finally speculates on the problems with lattice versions of the standard model.
Spontaneous violation of mirror symmetry
Dyatlov, Igor T
2015-01-01
A symmetry violation model is considered for a system that can spontaneously choose between identical states which differ from each other only in weak properties (R-L). Such mirror symmetry allows reproduction of observed qualitative properties of quark and lepton mixing matrices. The lepton mixing matrix evidences in this case in favor of the inverse mass spectrum and the Dirac nature of SM neutrino. Notwithstanding the Dirac properties of neutrino, an exchange of lepton numbers such as $e^{-}+\\mu^{+}\\rightarrow e^{+}+\\mu^{-}$ is possible but with only leptons participating in the process.
Symposium Symmetries in Science XIII
Gruber, Bruno J; Yoshinaga, Naotaka; Symmetries in Science XI
2005-01-01
This book is a collection of reviews and essays about the recent developments in the area of Symmetries and applications of Group Theory. Contributions have been written mostly at the graduate level but some are accessible to advanced undergraduates. The book is of interest to a wide audience and covers a broad range of topics with a strong degree of thematical unity. The book is part of a Series of books on Symmetries in Science and may be compared to the published Proceedings of the Colloquia on Group Theoretical Methods in Physics. Here, however, prevails a distinguished character for presenting extended reviews on present applications to Science, not restricted to Theoretical Physics.
Clifford algebraic symmetries in physics
International Nuclear Information System (INIS)
This paper reviews the following appearances of Clifford algebras in theoretical physics: statistical mechanics; general relativity; quantum electrodynamics; internal symmetries; the vee product; classical electrodynamics; charged-particle motion; and the Lorentz group. It is concluded that the power of the Clifford-algebraic description resides in its ability to perform representation-free calculations which are generalizations of the traditional vector algebra and that this considerable computational asset, in combination with the intrinsic symmetry, provides a practical framework for much of theoretical physics. 5 references
Optical metamaterials with quasicrystalline symmetry: symmetry-induced optical isotropy
International Nuclear Information System (INIS)
Taking advantage of symmetry considerations, we have analyzed the potential of various metamaterials to affect the polarization state of light upon oblique illumination. We have shown that depending on the angle of illumination, metamaterials are able to support specific polarization states. The presented methodology that using ellipticity and circular dichroism, provides an unambiguous language for discussing the impact of the inherent symmetry of the metamaterial lattices on their far-field response. Our findings allow the quantification analysis of the impact of inter-element coupling and lattice symmetry on the optical properties of metamaterials, and to separate this contribution from the response associated with a single meta-atom. In addition, we have studied the concept of optical quasicrystalline metamaterials, revealing that the absence of translational symmetry (periodicity) of quasicrystalline metamaterials causes an isotropic optical response, while the long-range positional order preserves the resonance properties. Our findings constitute an important step towards the design of optically isotropic metamaterials and metasurfaces. (authors)
Charge symmetry at the partonic level
Energy Technology Data Exchange (ETDEWEB)
Londergan, J. T.; Peng, J. C.; Thomas, A. W.
2010-07-01
This review article discusses the experimental and theoretical status of partonic charge symmetry. It is shown how the partonic content of various structure functions gets redefined when the assumption of charge symmetry is relaxed. We review various theoretical and phenomenological models for charge symmetry violation in parton distribution functions. We summarize the current experimental upper limits on charge symmetry violation in parton distributions. A series of experiments are presented, which might reveal partonic charge symmetry violation, or alternatively might lower the current upper limits on parton charge symmetry violation.
A model of intrinsic symmetry breaking
Energy Technology Data Exchange (ETDEWEB)
Ge, Li [Research Center for Quantum Manipulation, Department of Physics, Fudan University, Shanghai 200433 (China); Li, Sheng [Department of Physics, Zhejiang Normal University, Zhejiang 310004 (China); George, Thomas F., E-mail: tfgeorge@umsl.edu [Office of the Chancellor and Center for Nanoscience, Department of Chemistry and Biochemistry, University of Missouri-St. Louis, St. Louis, MO 63121 (United States); Department of Physics and Astronomy, University of Missouri-St. Louis, St. Louis, MO 63121 (United States); Sun, Xin, E-mail: xin_sun@fudan.edu.cn [Research Center for Quantum Manipulation, Department of Physics, Fudan University, Shanghai 200433 (China)
2013-11-01
Different from the symmetry breaking associated with a phase transition, which occurs when the controlling parameter is manipulated across a critical point, the symmetry breaking presented in this Letter does not need parameter manipulation. Instead, the system itself suddenly undergoes symmetry breaking at a certain time during its evolution, which is intrinsic symmetry breaking. Through a polymer model, it is revealed that the origin of the intrinsic symmetry breaking is nonlinearity, which produces instability at the instance when the evolution crosses an inflexion point, where this instability breaks the original symmetry.
Diffeomorphism symmetry in quantum gravity models
Dittrich, Bianca
2008-01-01
We review and discuss the role of diffeomorphism symmetry in quantum gravity models. Such models often involve a discretization of the space-time manifold as a regularization method. Generically this leads to a breaking of the symmetries to approximate ones, however there are incidences in which the symmetries are exactly preserved. Both kind of symmetries have to be taken into account in covariant and canonical theories in order to ensure the correct continuum limit. We will sketch how to identify exact and approximate symmetries in the action and how to define a corresponding canonical theory in which such symmetries are reflected as exact and approximate constraints.
Chiral symmetry in perturbative QCD
International Nuclear Information System (INIS)
The chiral symmetry of quantum chromodynamics with massless quarks is unbroken in perturbation theory. Dimensional regularization is used. The ratio of the vector and axial vector renormalization constante is shown to be independent of the renormalization mass. The general results are explicitly verified to fourth order in g, the QCD coupling constant
Strong coupling electroweak symmetry breaking
Energy Technology Data Exchange (ETDEWEB)
Barklow, T.L. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Burdman, G. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Physics; Chivukula, R.S. [Boston Univ., MA (United States). Dept. of Physics
1997-04-01
The authors review models of electroweak symmetry breaking due to new strong interactions at the TeV energy scale and discuss the prospects for their experimental tests. They emphasize the direct observation of the new interactions through high-energy scattering of vector bosons. They also discuss indirect probes of the new interactions and exotic particles predicted by specific theoretical models.
Quantitative Analysis of Face Symmetry.
Tamir, Abraham
2015-06-01
The major objective of this article was to report quantitatively the degree of human face symmetry for reported images taken from the Internet. From the original image of a certain person that appears in the center of each triplet, 2 symmetric combinations were constructed that are based on the left part of the image and its mirror image (left-left) and on the right part of the image and its mirror image (right-right). By applying a computer software that enables to determine length, surface area, and perimeter of any geometric shape, the following measurements were obtained for each triplet: face perimeter and area; distance between the pupils; mouth length; its perimeter and area; nose length and face length, usually below the ears; as well as the area and perimeter of the pupils. Then, for each of the above measurements, the value C, which characterizes the degree of symmetry of the real image with respect to the combinations right-right and left-left, was calculated. C appears on the right-hand side below each image. A high value of C indicates a low symmetry, and as the value is decreasing, the symmetry is increasing. The magnitude on the left relates to the pupils and compares the difference between the area and perimeter of the 2 pupils. The major conclusion arrived at here is that the human face is asymmetric to some degree; the degree of asymmetry is reported quantitatively under each portrait. PMID:26080172
Fundamental Symmetries and Conservation Laws
International Nuclear Information System (INIS)
I discuss recent progress in low-energy tests of symmetries and conservation laws, including parity nonconservation in atoms and nuclei, electric dipole moment tests of time-reversal invariance, β-decay correlation studies, and decays violating separate (family) and total lepton number.
Instantons and chiral symmetry breaking
International Nuclear Information System (INIS)
A detailed investigation of chiral symmetry breaking due to instanton dynamics is carried out, within the framework of the dilute gas approximation, for quarks in both the fundamental and adjoint representations of SU(2). The momentum dependence of the dynamical mass is found to be very similar in each representation. (orig.)
Turning Students into Symmetry Detectives
Wilders, Richard; VanOyen, Lawrence
2011-01-01
Exploring mathematical symmetry is one way of increasing students' understanding of art. By asking students to search designs and become pattern detectives, teachers can potentially increase their appreciation of art while reinforcing their perception of the use of math in their day-to-day lives. This article shows teachers how they can interest…
Experimental tests of fundamental symmetries
Jungmann, K. P.
2014-01-01
Ongoing experiments and projects to test our understanding of fundamental inter- actions and symmetries in nature have progressed significantly in the past few years. At high energies the long searched for Higgs boson has been found; tests of gravity for antimatter have come closer to reality; Loren
Symmetry structure and phase transitions
Indian Academy of Sciences (India)
Ashok Goyal; Meenu Dahiya; Deepak Chandra
2003-05-01
We study chiral symmetry structure at ﬁnite density and temperature in the presence of external magnetic ﬁeld and gravity, a situation relevant in the early Universe and in the core of compact stars. We then investigate the dynamical evolution of phase transition in the expanding early Universe and possible formation of quark nuggets and their survival.
Superdeformations and fermion dynamical symmetries
International Nuclear Information System (INIS)
In this talk, I will present a link between nuclear collective motions and their underlying fermion dynamical symmetries. In particular, I will focus on the microscopic understanding of deformations. It is shown that the SU3 of the one major shell fermion dynamical symmetry model (FDSM) is responsible for the physics of low and high spins in normal deformation. For the recently observed phenomena of superdeformation, the physics of the problem dictates a generalization to a supershell structure (SFDSM), which also has an SU3 fermion dynamical symmetry. Many recently discovered feature of superdeformation are found to be inherent in such an SU3 symmetry. In both cases the dynamical Pauli effect plays a vital role. A particularly noteworthy discovery from this model is that the superdeformed ground band is not the usual unaligned band but the D-pair aligned (DPA) band, which sharply crosses the excited bands. The existence of such DPA band is a key point to understand many properties of superdeformation. Our studies also poses new experimental challenge. This is particularly interesting since there are now plans to build new and exciting γ-ray detecting systems, like the GAMMASPHERE, which could provide answers to some of these challenges. 34 refs., 11 figs., 5 tabs
Hidden Local Symmetry and Beyond
Yamawaki, Koichi
2016-01-01
Gerry Brown was a godfather of our hidden local symmetry (HLS) for the vector meson from the birth of the theory throughout his life. The HLS is originated from very nature of the nonlinear realization of the symmetry G based on the manifold G/H, and thus is universal to any physics based on the nonlinear realization. Here I focus on the Higgs Lagrangian of the Standard Model (SM), which is shown to be equivalent to the nonlinear sigma model based on G/H= SU(2)_L x SU(2)_R/SU(2)_V with additional symmetry, the nonlinearly realized scale symmetry. Then the SM does have a dynamical gauge boson of the SU(2)_V HLS, "SM rho meson", in addition to the Higgs as a pseudo dilaton as well as the NG bosons to be absorbed into the W and Z. Based on the recent work done with S. Matsuzaki and H. Ohki, I discuss a novel possibility that the SM rho meson acquires kinetic term by the SM dynamics itself, which then stabilizes the skyrmion dormant in the SM as a viable candidate for the dark matter, what we call "Dark SM skyrmi...
Quantum group and quantum symmetry
International Nuclear Information System (INIS)
This is a self-contained review on the theory of quantum group and its applications to modern physics. A brief introduction is given to the Yang-Baxter equation in integrable quantum field theory and lattice statistical physics. The quantum group is primarily introduced as a systematic method for solving the Yang-Baxter equation. Quantum group theory is presented within the framework of quantum double through quantizing Lie bi-algebra. Both the highest weight and the cyclic representations are investigated for the quantum group and emphasis is laid on the new features of representations for q being a root of unity. Quantum symmetries are explored in selected topics of modern physics. For a Hamiltonian system the quantum symmetry is an enlarged symmetry that maintains invariance of equations of motion and allows a deformation of the Hamiltonian and symplectic form. The configuration space of the integrable lattice model is analyzed in terms of the representation theory of quantum group. By means of constructing the Young operators of quantum group, the Schroedinger equation of the model is transformed to be a set of coupled linear equations that can be solved by the standard method. Quantum symmetry of the minimal model and the WZNW model in conformal field theory is a hidden symmetry expressed in terms of screened vertex operators, and has a deep interplay with the Virasoro algebra. In quantum group approach a complete description for vibrating and rotating diatomic molecules is given. The exact selection rules and wave functions are obtained. The Taylor expansion of the analytic formulas of the approach reproduces the famous Dunham expansion. (author). 133 refs, 20 figs
PT Symmetry, Conformal Symmetry, and the Metrication of Electromagnetism
Mannheim, Philip D.
2016-05-01
We present some interesting connections between PT symmetry and conformal symmetry. We use them to develop a metricated theory of electromagnetism in which the electromagnetic field is present in the geometric connection. However, unlike Weyl who first advanced this possibility, we do not take the connection to be real but to instead be PT symmetric, with it being iA_{μ } rather than A_{μ } itself that then appears in the connection. With this modification the standard minimal coupling of electromagnetism to fermions is obtained. Through the use of torsion we obtain a metricated theory of electromagnetism that treats its electric and magnetic sectors symmetrically, with a conformal invariant theory of gravity being found to emerge. An extension to the non-Abelian case is provided.
Noether gauge symmetry approach in quintom cosmology
Aslam, Adnan; Momeni, Davood; Myrzakulov, Ratbay; Rashid, Muneer Ahmad; Raza, Muhammad
2013-01-01
In literature usual point like symmetries of the Lagrangian have been introduced to study the symmetries and the structure of the fields. This kind of Noether symmetry is a subclass of a more general family of symmetries, called Noether Gauge Symmetries (NGS). Motivated by this mathematical tool, in this article, we discuss the generalized Noether symmetry of Quintom model of dark energy, which is a two component fluid model of quintessence and phantom fields. Our model is a generalization of the Noether symmetries of a single and multiple components which have been investigated in detail before. We found the general form of the quintom potential in which the whole dynamical system has a point like symmetry. We investigated different possible solutions of the system for diverse family of gauge function. Specially, we discovered two family of potentials, one corresponds to a free quintessence (phantom) and the second is in the form of quadratic interaction between two components. These two families of potentia...
Site symmetry and crystal symmetry: a spherical tensor analysis
Brouder, Christian; Juhin, Amélie; Bordage, Amélie; Arrio, Marie-Anne
2008-01-01
27 pages, 3 figures International audience The relation between the properties of a specific crystallographic site and the properties of the full crystal is discussed by using spherical tensors. The concept of spherical tensors is introduced and the way it transforms under the symmetry operations of the site and from site to site is described in detail. The law of spherical tensor coupling is given and illustrated with the example of the electric dipole and quadrupole transitions in x-r...
Feshbach resonances and weakly bound molecular states of boson-boson and boson-fermion NaK pairs
Viel, Alexandra; Simoni, Andrea
2016-01-01
We study theoretically magnetically induced Feshbach resonances and near-threshold bound states in isotopic NaK pairs. Our calculations accurately reproduce Feshbach spectroscopy data on Na$^{40}$K and explain the origin of the observed multiplets in the p-wave [Phys. Rev. A 85, 051602(R) (2012)]. We apply the model to predict scattering and bound state threshold properties of the boson-boson Na$^{39}$K and Na$^{41}$K systems. We find that the Na$^{39}$K isotopic pair presents broad magnetic ...
Feshbach resonances and weakly bound molecular states of boson-boson and boson-fermion NaK pairs
Viel, Alexandra; Simoni, Andrea
2016-04-01
We conduct a theoretical study of magnetically induced Feshbach resonances and near-threshold bound states in isotopic NaK pairs. Our calculations accurately reproduce Feshbach spectroscopy data on Na 40K and explain the origin of the observed multiplets in the p wave [Phys. Rev. A 85, 051602(R) (2012), 10.1103/PhysRevA.85.051602]. We apply the model to predict scattering and bound state threshold properties of the boson-boson Na 39K and Na 41K systems. We find that the Na 39K isotopic pair presents broad magnetic Feshbach resonances and favorable ground-state features for producing nonreactive polar molecules by two-photon association. Broad s -wave resonances are also predicted for Na 41K collisions.
On the definition of cylindrical symmetry
Carot, J.; Senovilla, J. M. M.; Vera, R
1999-01-01
The standard definition of cylindrical symmetry in General Relativity is reviewed. Taking the view that axial symmetry is an essential pre-requisite for cylindrical symmetry, it is argued that the requirement of orthogonal transitivity of the isometry group should be dropped, this leading to a new, more general definition of cylindrical symmetry. Stationarity and staticity in cylindrically symmetric spacetimes are then defined, and these issues are analysed in connection with orthogonal trans...
Yet another symmetry breaking to be discovered
Yoshimura, M
2016-01-01
The discovery of spontaneous symmetry breaking in particle physics was the greatest contribution in Nambu's achievements. There is another class of symmetries that exist in the low energy nature, yet is doomed to be broken at high energy, due to a lack of protection of the gauge symmetry. I shall review our approach to search for this class of symmetry breaking, the lepton number violation linked to generation of the matter-antimatter asymmetry in our universe.
Symmetry energy in nuclear density functional theory
W. Nazarewicz; Reinhard, P. -G.; Satula, W.; Vretenar, D.
2013-01-01
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...
Yet another symmetry breaking to be discovered
Yoshimura, M.
2016-07-01
The discovery of spontaneous symmetry breaking in particle physics was the greatest contribution in Nambu's achievements. There is another class of symmetries that exist in low-energy nature, yet is doomed to be broken at high energy, due to a lack of protection of the gauge symmetry. I shall review our approach to searching for this class of symmetry breaking, the lepton number violation linked to the generation of the matter-antimatter asymmetry in our universe.
Symmetry Breaking for Black-Scholes Equations
Institute of Scientific and Technical Information of China (English)
YANG Xuan-Liu; ZHANG Shun-Li; QU Chang-Zheng
2007-01-01
Black-Scholes equation is used to model stock option pricing. In this paper, optimal systems with one to four parameters of Lie point symmetries for Black-Scholes equation and its extension are obtained. Their symmetry breaking interaction associated with the optimal systems is also studied. As a result, symmetry reductions and corresponding solutions for the resulting equations are obtained.
Symmetry Breaking for Black-Scholes Equations
Yang, Xuan-Liu; Zhang, Shun-Li; Qu, Chang-Zheng
2007-06-01
Black-Scholes equation is used to model stock option pricing. In this paper, optimal systems with one to four parameters of Lie point symmetries for Black-Scholes equation and its extension are obtained. Their symmetry breaking interaction associated with the optimal systems is also studied. As a result, symmetry reductions and corresponding solutions for the resulting equations are obtained.
Symmetry Breaking for Black-Scholes Equations
International Nuclear Information System (INIS)
Black-Scholes equation is used to model stock option pricing. In this paper, optimal systems with one to four parameters of Lie point symmetries for Black-Scholes equation and its extension are obtained. Their symmetry breaking interaction associated with the optimal systems is also studied. As a result, symmetry reductions and corresponding solutions for the resulting equations are obtained.
Symmetry and electromagnetism. Simetria y electromagnetismo
Energy Technology Data Exchange (ETDEWEB)
Fuentes Cobas, L.E.; Font Hernandez, R.
1993-01-01
An analytical treatment of electrostatic and magnetostatic field symmetry, as a function of charge and current distribution symmetry, is proposed. The Newmann Principle, related to the cause-effect symmetry relation, is presented and applied to the characterization of simple configurations. (Author) 5 refs.
Relativistic dissipative hydrodynamics with spontaneous symmetry breaking
Pujol, C
2003-01-01
In this paper we consider dissipative hydrodynamic equations for systems with continuous broken symmetries. We first present the case of superfluidity, in which the symmetry U(1) is broken and then generalize to the chiral symmetry $SU(2)_L \\times SU(2)_R$. New transport coefficients are introduced and the consequences of their existence are discussed.
Symmetries of the dissipative Hofstadter model
Freed, D E
1993-01-01
The dissipative Hofstadter model, which describes a particle in 2-D subject to a periodic potential, uniform magnetic field, and dissipation, is also related to open string boundary states. This model exhibits an SL(2,Z) duality symmetry and hidden reparametrization invariance symmetries. These symmetries are useful for finding exact solutions for correlation functions.
Symmetry study of the coupled Burgers system
Energy Technology Data Exchange (ETDEWEB)
Lian Zengju [Department of Physics, Ningbo University, Ningbo 315211 (China); Lou, S.Y. [Department of Physics, Ningbo University, Ningbo 315211 (China); Department of Physics, Shanghai Jiao Tong University, Shanghai 200030 (China)
2006-01-01
The inverse of the recursion operator of a coupled Burgers equation is given explicitly. Three sets of infinitely many symmetries of the considered model are obtained by acting the recursion operator and it's inverse on the trivial symmetries, space translation, identity transformation and the scaling transformation respectively. These symmetries constitute an infinite dimensional Lie algebra.
Symmetry study of the coupled Burgers system
International Nuclear Information System (INIS)
The inverse of the recursion operator of a coupled Burgers equation is given explicitly. Three sets of infinitely many symmetries of the considered model are obtained by acting the recursion operator and it's inverse on the trivial symmetries, space translation, identity transformation and the scaling transformation respectively. These symmetries constitute an infinite dimensional Lie algebra
General Formalism for the BRST Symmetry
International Nuclear Information System (INIS)
Abstract In this paper we will discuss Faddeev—Popov method for gauge theories with a general form of gauge symmetry in an abstract way. We will then develope a general formalism for dealing with the BRST symmetry. This formalism will make it possible to analyse the BRST symmetry for any theory. (physics of elementary particles and fields)
Electroweak symmetry breaking at photon colliders
International Nuclear Information System (INIS)
The electroweak-symmetry-breaking sector of the standard model can be weakly-coupled or can be strongly-coupled, which is characterized by some kinds of strong interaction among the Goldstone bosons of the electroweak-symmetry-breaking sector. In this paper, we summarize an investigation of probing the strong electroweak-symmetry-breaking effects at photon colliders. ((orig.))
Dark Matter and Global Symmetries
Mambrini, Yann; Queiroz, Farinaldo S
2015-01-01
General considerations in general relativity and quantum mechanics rule out global symmetries in the context of any consistent theory of quantum gravity. Motivated by this, we derive stringent and robust bounds from gamma-ray, X-ray, cosmic ray, neutrino and CMB data on models that invoke global symmetries to stabilize the dark matter particle. Under realistic assumptions we are able to rule out fermionic, vector, and scalar dark matter candidates across a broad mass range (keV-TeV), including the WIMP regime. We then specialize our analysis and apply our bounds to specific models such as the Two-Higgs-Doublet, Left-Right, Singlet Fermionic, Zee-Babu, 3-3-1 and Radiative See-Saw models. In the supplemental material we derive robust, updated model-independent limits on the dark matter lifetime.
Symmetry breaking in supersymmetric GUTs
International Nuclear Information System (INIS)
This paper analyzes the first step of symmetry breaking in N=1 supersymmetric unified theories. The possible patterns of gauge symmetry breaking consistent with supersymmetry are characterized. Some well-known properties of the scalar potential in supersymmetric gauge theories are reviewed. Simple methods to discover which v.e.v.'s of a given multiplet of scalar fields are consistent with the conditions of given equations are introduced. The vanishing of the D2-term and of the F2-term is discussed and a simple lemma derived from the former. The results of these discussions are applied to some possible candidates for a supersymmetric gauge theory based on the gauge groups SU(5), 0(10), and E6
Spinor structure and internal symmetries
Varlamov, V V
2014-01-01
Space-time and internal symmetries are considered within one theoretical framework based on the generalized spin and abstract Hilbert space. Complex momentum is understood as a generating kernel of the underlying spinor structure. It is shown that tensor products of biquaternion algebras are associated with the each irreducible representation of the Lorentz group. Space-time discrete symmetries $P$, $T$ and their combination $PT$ are generated by the fundamental automorphisms of this algebraic background (Clifford algebras). Charge conjugation $C$ is presented by a pseudoautomorphism of the complex Clifford algebra. This description of the operation $C$ allows one to distinguish charged and neutral particles including particle-antiparticle interchange and truly neutral particles. Quotient representations of the Lorentz group and their possible relations with $P$- and $CP$-violations are considered. Spin and charge multiplets, based on the interlocking representations of the Lorentz group, are introduced. A ce...
Ether symmetry unification theory (ESU)
International Nuclear Information System (INIS)
The ether symmetry unification (ESU) theory postulates a mechanism that accounts for the formation of the universe as well as the formation of the original mass particles following the big bang. The essential role of the medium-vacuum of the theory of prerelativity is explained. The ultra-high energy particles described in the Ether Symmetry Unification Theory are compared with high energy magnetic monopoles described by Supersymmetry. Phase transitions of high energy events to low energy events and the associated media-vacua involved, postulated by the ESU, are then compared to the low energy events of the standard model within the critical phases of the first two seconds of quantum field theory's time line
Quantum Solitons with Cylindrical Symmetry
Chepilko, N.; Kobushkin, A.; Syamtomov, A.
1993-01-01
Soliton solutions with cylindrical symmetry are investigated within the nonlinear $\\sigma $-model disregarding the Skyrme-stabilization term. The solitons are stabilized by quantization of collective breathing mode and collapse in the $\\hbar \\to 0$ limit. It is shown that for such stabilization mechanism the model, apart from solitons with integer topological number $B$, admits the solitons with half-odd $B$. The solitons with integer $B$ have standard spin-isospin classification, while $B={\\...
Symmetry analysis of talus bone
Islam, K.; Dobbe, A.; Komeili, A.; Duke, K; EL-RICH,M; Dhillon, S.; Adeeb, S.; Jomha, N. M.
2014-01-01
Objective The main object of this study was to use a geometric morphometric approach to quantify the left-right symmetry of talus bones. Methods Analysis was carried out using CT scan images of 11 pairs of intact tali. Two important geometric parameters, volume and surface area, were quantified for left and right talus bones. The geometric shape variations between the right and left talus bones were also measured using deviation analysis. Furthermore, location of asymmetry in the geometric sh...
Wormhole dynamics in spherical symmetry
Hayward, Sean A.
2009-01-01
A dynamical theory of traversable wormholes is detailed in spherical symmetry. Generically a wormhole consists of a tunnel of trapped surfaces between two mouths, defined as temporal outer trapping horizons with opposite senses, in mutual causal contact. In static cases, the mouths coincide as the throat of a Morris-Thorne wormhole, with surface gravity providing an invariant measure of the radial curvature or "flaring-out". The null energy condition must be violated at a wormhole mouth. Zero...
Symmetry Doubling: Doubly General Relativity
Gomes, Henrique; Koslowski, Tim
2012-01-01
Using a BRST treatment, we show that the equivalence of General Relativity and Shape Dynamics can be extended to a theory that respects the BRST-symmetries of General Relativity as well as the ones of an extended version of Shape Dynamics. This version of Shape Dynamics implements local spatial Weyl transformations as well as a local and abstract analogue of special conformal transformations. Standard effective field theory arguments suggest that the definition of a gravity theory should impl...
Chiral symmetry and nucleon structure
Energy Technology Data Exchange (ETDEWEB)
Holstein, B.R. (Massachusetts Univ., Amherst, MA (United States). Dept. of Physics and Astromony Washington Univ., Seattle, WA (United States). Inst. for Nuclear Theory)
1992-01-01
Recently it has been realized that significant tests of the validity of QCD are available in low energy experiments (E < 500 MeV) by exploiting the property of (broken) chiral symmetry. This technique has been highly developed in The Goldstone boson sector by the work of Gasser and Leutwyler. Application to the nucleon system is much more difficult and is now being carefully developed.
Symmetries in Quantum Schubert Calculus
Hengelbrock, Harald
2003-01-01
Die Arbeit befasst sich mit dem Quantenkohomologiering von Grassmannschen Varietäten. Ich definiere eine Involution auf dem Quantenkohomologiering, welche mit komplexer Konjugation auf dessen Spektrum zusammenhängt, und eine Art Inversion definiert. Zusammen mit der von Agnihotri und Woodward entdeckten zyklischen Symmetrie des Quantenkohomologierings erzeugen diese Symmetrien den Nullraum der Bilinearform, welche als die Summe von Koeffizienten in der Entwicklung von Produkten be...
Chiral symmetry in rotating systems
Malik, Sham S.
2015-08-01
The triaxial rotating system at critical angular momentum I ≥Iband exhibits two enatiomeric (the left- and right-handed) forms. These enatiomers are related to each other through dynamical chiral symmetry. The chiral symmetry in rotating system is defined by an operator χ ˆ =Rˆy (π) T ˆ, which involves the product of two distinct symmetries, namely, continuous and discrete. Therefore, new guidelines are required for testing its commutation with the system Hamiltonian. One of the primary objectives of this study is to lay down these guidelines. Further, the possible impact of chiral symmetry on the geometrical arrangement of angular momentum vectors and investigation of observables unique to nuclear chiral-twins is carried out. In our model, the angular momentum components (J1, J2, J3) occupy three mutually perpendicular axes of triaxial shape and represent a non-planar configuration. At certain threshold energy, the equation of motion in angular momentum develops a second order phase transition and as a result two distinct frames (i.e., the left- and right-handed) are formed. These left- and right-handed states correspond to a double well system and are related to each other through chiral operator. At this critical angular momentum, the centrifugal and Coriolis interactions lower the barrier in the double well system. The tunneling through the double well starts, which subsequently lifts the degeneracy among the rotational states. A detailed analysis of the behavior of rotational energies, spin-staggering, and the electromagnetic transition probabilities of the resulting twin-rotational bands is presented. The ensuing model results exhibit similarities with many observed features of the chiral-twins. An advantage of our formalism is that it is quite simple and it allows us to pinpoint the understanding of physical phenomenon which lead to chiral-twins in rotating systems.
Duality symmetry for star products
V. I. Man'ko; Marmo, G.; Vitale, P.
2004-01-01
A duality property for star products is exhibited. In view of it, known star-product schemes, like the Weyl-Wigner-Moyal formalism, the Husimi and the Glauber-Sudarshan maps are revisited and their dual partners elucidated. The tomographic map, which has been recently described as yet another star product scheme, is considered. It yields a noncommutative algebra of operator symbols which are positive definite probability distributions. Through the duality symmetry a new noncommutative algebra...
Weigert, Stefan
2006-01-01
A fundamental problem in the theory of PT-invariant quantum systems is to determine whether a given system `respects' this symmetry or not. If not, the system usually develops non-real eigenvalues. It is shown in this contribution how to algorithmically detect the existence of complex eigenvalues for a given PT-symmetric matrix. The procedure uses classical results from stability theory which qualitatively locate the zeros of real polynomials in the complex plane. The interest and value of th...
Geometric symmetries in light nuclei
Bijker, Roelof
2016-01-01
The algebraic cluster model is is applied to study cluster states in the nuclei 12C and 16O. The observed level sequences can be understood in terms of the underlying discrete symmetry that characterizes the geometrical configuration of the alpha-particles, i.e. an equilateral triangle for 12C, and a regular tetrahedron for 16O. The structure of rotational bands provides a fingerprint of the underlying geometrical configuration of alpha-particles.
Discrete Symmetries/Discrete Theories
Bose, Milton; Dine, Michael
2012-01-01
Dynamical, metastable supersymmetry breaking appears to be a generic phenomena in supersymmetric field theories. It's simplest implementation is within the so-called "retrofitted O'Raifeartaigh Models". While seemingly flexible, model building in these theories is significantly constrained. In gauge-mediated versions, if the approximate $R$ symmetry of the theory is spontaneously broken, the messenger scale is fixed; if explicitly broken by retrofitted couplings, a very small dimensionless nu...
Dark matter and global symmetries
Mambrini, Yann; Profumo, Stefano; Queiroz, Farinaldo S.
2016-09-01
General considerations in general relativity and quantum mechanics are known to potentially rule out continuous global symmetries in the context of any consistent theory of quantum gravity. Assuming the validity of such considerations, we derive stringent bounds from gamma-ray, X-ray, cosmic-ray, neutrino, and CMB data on models that invoke global symmetries to stabilize the dark matter particle. We compute up-to-date, robust model-independent limits on the dark matter lifetime for a variety of Planck-scale suppressed dimension-five effective operators. We then specialize our analysis and apply our bounds to specific models including the Two-Higgs-Doublet, Left-Right, Singlet Fermionic, Zee-Babu, 3-3-1 and Radiative See-Saw models. Assuming that (i) global symmetries are broken at the Planck scale, that (ii) the non-renormalizable operators mediating dark matter decay have O (1) couplings, that (iii) the dark matter is a singlet field, and that (iv) the dark matter density distribution is well described by a NFW profile, we are able to rule out fermionic, vector, and scalar dark matter candidates across a broad mass range (keV-TeV), including the WIMP regime.
Infinitesimal symmetries: a computational approach
International Nuclear Information System (INIS)
This thesis is concerned with computational aspects in the determination of infinitesimal symmetries and Lie-Baecklund transformations of differential equations. Moreover some problems are calculated explicitly. A brief introduction to some concepts in the theory of symmetries and Lie-Baecklund transformations, relevant for this thesis, are given. The mathematical formalism is shortly reviewed. The jet bundle formulation is chosen, in which, by its algebraic nature, objects can be described very precisely. Consequently it is appropriate for implementation. A number of procedures are discussed, which enable to carry through computations with the help of a computer. These computations are very extensive in practice. The Lie algebras of infinitesimal symmetries of a number of differential equations in Mathematical Physics are established and some of their applications are discussed, i.e., Maxwell equations, nonlinear diffusion equation, nonlinear Schroedinger equation, nonlinear Dirac equations and self dual SU(2) Yang-Mills equations. Lie-Baecklund transformations of Burgers' equation, Classical Boussinesq equation and the Massive Thirring Model are determined. Furthermore, nonlocal Lie-Baecklund transformations of the last equation are derived. (orig.)
Painlevé property, symmetries and symmetry reductions of the coupled Burgers system
Lian, Zeng-Ju; Chen, Li-Li; Lou, Sen-Yue
2005-08-01
The Painlevé property, inverse recursion operator, infinite number of symmetries and Lie symmetry reductions of the coupled Burgers equation are given explicitly. Three sets of infinitely many symmetries of the considered model are obtained by acting the recursion operator and the inverse recursion operator on the trivial symmetries such as the identity transformation, the space translation and the scaling transformation respectively. These symmetries constitute an infinite dimensional Lie algebra while its finite dimensional Lie point symmetry subalgebra is used to find possible symmetry reductions and then the group invariant solutions.
Symmetries and constant mean curvature surfaces
International Nuclear Information System (INIS)
In this paper, we discuss the Lie symmetries, symmetry algebra and symmetry reductions of the equation which describes constant mean curvature surfaces via the generalized Weierstrass-Enneper formulae. First we point out that the equation admits an infinite-dimensional symmetry Lie algebra. Then using symmetry reductions, we obtain two integrable Hamiltonian systems (one autonomous, the other nonautonomous) with two degrees of freedom. The autonomous one was obtained by Konopelchenko and Taimanov by other means. Our method provides a new approach for construction of constant mean curvature surfaces. (author)
Assessing symmetry of financial returns series
Coronel-Brizio, H F; Rodriguez-Achach, M
2007-01-01
Testing symmetry of a probability distribution is a common question arising from applications in several fields. Particularly, in the study of observables used in the analysis of stock market index variations, the question of symmetry has not been fully investigated by means of statistical procedures. In this work a distribution-free test statistic Tn for testing symmetry, derived by Einmahl and McKeague, based on the empirical likelihood approach, is used to address the study of symmetry of financial returns. The asymptotic points of the test statistic Tn are also calculated and a procedure for assessing symmetry for the analysis of the returns of stock market indices is presented.
Neutrino masses and spontaneously broken flavor symmetries
International Nuclear Information System (INIS)
We study the phenomenology of supersymmetric flavor models. We show how the predictions of models based on spontaneously broken non-Abelian discrete flavor symmetries are altered when we include so-called Kaehler corrections. Furthermore, we discuss anomaly-free discrete R symmetries which are compatible with SU(5) unification. We find a set of symmetries compatible with suppressed Dirac neutrino masses and a unique symmetry consistent with the Weinberg operator. We also study a pseudo-anomalous U(1)R symmetry which explains the fermion mass hierarchies and, when amended with additional singlet fields, ameliorates the fine-tuning problem.
The Symmetry of Optical Field in Photonic Crystal Fibre with Trigonal Symmetry
Directory of Open Access Journals (Sweden)
Ivan Turek
2006-01-01
Full Text Available Some photographs of intensity of optical field of a photonic crystal fibre are presented in the contribution. Presented photographs document that the symmetry of photonic crystal creating the cladding of fibre is manifested in the symmetry of distribution of the optical field intensity. In case when more modes are excited in the fibre the symmetry of the generated field can be different as the symmetry of the eventual modes. How the symmetry may be changed is illustrated by amodel example.
Symmetries, Integrals and Solutions of Ordinary Differential Equations of Maximal Symmetry
Indian Academy of Sciences (India)
P G L Leach; R R Warne; N Caister; V Naicker; N Euler
2010-02-01
Second-and third-order scalar ordinary differential equations of maximal symmetry in the traditional sense of point, respectively contact, symmetry are examined for the mappings they produce in solutions and fundamental first integrals. The properties of the `exceptional symmetries’, i.e. those not considered to be generic to scalar equations of maximal symmetry, can be recast into a form which is applicable to all such equations of maximal symmetry. Some properties of these symmetries are demonstrated.
Mei Symmetry and Noether Symmetry of the Relativistic Variable Mass System
Institute of Scientific and Technical Information of China (English)
FANG Jian-Hui
2004-01-01
The definition and criterion of the Mei symmetry of a relativistic variable mass system are given. The relation between the Mei symmetry and the Noether symmetry of the system is found under infinitesimal transformations of groups. The conserved quantities to which the Mei symmetry and Noether symmetry of the system lead are obtained.An example is given to illustrate the application of the result.
Brain Activity in Response to Visual Symmetry
Directory of Open Access Journals (Sweden)
Marco Bertamini
2014-12-01
Full Text Available A number of studies have explored visual symmetry processing by measuring event related potentials and neural oscillatory activity. There is a sustained posterior negativity (SPN related to the presence of symmetry. There is also functional magnetic resonance imaging (MRI activity in extrastriate visual areas and in the lateral occipital complex. We summarise the evidence by answering six questions. (1 Is there an automatic and sustained response to symmetry in visual areas? Answer: Yes, and this suggests automatic processing of symmetry. (2 Which brain areas are involved in symmetry perception? Answer: There is an extended network from extrastriate areas to higher areas. (3 Is reflection special? Answer: Reflection is the optimal stimulus for a more general regularity-sensitive network. (4 Is the response to symmetry independent of view angle? Answer: When people classify patterns as symmetrical or random, the response to symmetry is view-invariant. When people attend to other dimensions, the network responds to residual regularity in the image. (5 How are brain rhythms in the two hemispheres altered during symmetry perception? Answer: Symmetry processing (rather than presence produces more alpha desynchronization in the right posterior regions. Finally, (6 does symmetry processing produce positive affect? Answer: Not in the strongest sense, but behavioural measures reveal implicit positive evaluation of abstract symmetry.
Models of Flavor with Discrete Symmetries
Aranda, A
2002-01-01
In an attempt to understand the observed patterns of lepton and quark masses, models invoking a flavor symmetry $G_f$, under which the Standard Model generations are charged, have been proposed. One particularly successful symmetry, U(2), has been extensively discussed in the literature. The Yukawa matrices in models based on this symmetry reproduce the observed mass ratios in the lepton and quark sectors. The features of the symmetry that determine the texture of the Yukawa matrices can be found in other symmetries as well. We present a model based on a minimal, non-Abelian discrete symmetry that reproduces the Yukawa matrices associated with U(2) theories of flavor. In addition to reproducing the mass and mixing angle relations obtained in such theories, the different representation structure of our new horizontal symmetry allows for solutions to the solar and atmospheric neutrino problems.
Quantum mechanics. Symmetries. 5. corr. ed.
International Nuclear Information System (INIS)
The volume quantum mechanics treats the as elegant as mighty theory of the symmetry groups and their application in quantum mechanics and the theory of the elementary particles. By means of many examples and problems with worked-out solutions the application of the fundamental principles to realistic problems is elucidated. The themes are symmetries in quantum mechanics, representations of the algebra of the angular momentum operators as generators of the SO(3) group. fundamental properties of Lie groups as mathematical supplement, symmetry groups and their physical meaning, thr isospin group, the hypercharge, quarks and the symmetry group SU(3), representations of the permutation group and Young diagrams, group characters as mathematical supplement, charm and the symmetry group SU(4), Cartan-Weyl claasification as mathematical supplement, special discrete symmetries, dynamical symmetries and the hydrogen atom, non-compact Lie groups as mathematical supplement, a proof of Racah's theorem.
Symmetries and symmetry breaking beyond the electroweak theory
International Nuclear Information System (INIS)
The Glashow-Salam-Weinberg theory describing electroweak interactions is one of the best successes of quantum field theory; it has passed all the experimental tests of particles physics with a high accuracy. However, this theory suffers from some deficiencies in the sense that some parameters, especially those involved in the generation of the mass of the elementary particles, are fixed to unnatural values. Moreover gravitation whose quantization cannot be achieved in ordinary quantum filed theory is hot taken into account. The aim of this PhD dissertation is to study some theories beyond the Standard Model and inspired by superstring theories. My endeavour has been to develop theoretical aspects of an effective dynamical description of one of the soltonic states of the strongly coupled strings. An important part of my results is also devoted to a more phenomenological analysis of the low energy effects of the symmetries that assure the coherence of the theories at high energy: these symmetries could explain the fermion mass hierarchy and could be directly observable in collider experiments. It is also shown how the geometrical properties of compactified spaces characterize the vacuum of string theory in a non-perturbative regime; such a vacuum can be used to construct a unified theory of gauge and gravitational interactions with a supersymmetry softy broken at a TcV scale. (author)
History of electroweak symmetry breaking
Kibble, T W B
2015-01-01
In this talk, I recall the history of the development of the unified electroweak theory, incorporating the symmetry-breaking Higgs mechanism, as I saw it from my standpoint as a member of Abdus Salam's group at Imperial College. I start by describing the state of physics in the years after the Second World War, explain how the goal of a unified gauge theory of weak and electromagnetic interactions emerged, the obstacles encountered, in particular the Goldstone theorem, and how they were overcome, followed by a brief account of more recent history, culminating in the historic discovery of the Higgs boson in 2012.
Renormalization Method and Mirror Symmetry
Directory of Open Access Journals (Sweden)
Si Li
2012-12-01
Full Text Available This is a brief summary of our works [arXiv:1112.4063, arXiv:1201.4501] on constructing higher genus B-model from perturbative quantization of BCOV theory. We analyze Givental's symplectic loop space formalism in the context of B-model geometry on Calabi-Yau manifolds, and explain the Fock space construction via the renormalization techniques of gauge theory. We also give a physics interpretation of the Virasoro constraints as the symmetry of the classical BCOV action functional, and discuss the Virasoro constraints in the quantum theory.
Lloyd, David R.
2010-01-01
Plato writes about Beauty in many of his dialogues, particularly in the Symposium, but he has no word equivalent to our "Symmetry", and this concept was not then formalised. Nevertheless, there are indications that some aspects of the concept were understood, if only intuitively. Plato has a very abstract concept of beauty, and when he uses "beauty" to characterise the so-called "Platonic Solids" in the Timaeus, he seems to be emphasising at least their regularity. It can be argued that the w...
Killing Symmetry on Finsler Manifold
Ootsuka, Takayoshi; Ishida, Muneyuki
2016-01-01
Killing vector fields $K$ are defined on Finsler manifold. The Killing symmetry is reformulated simply as $\\delta K^\\flat =0$ by using the Killing non-linear 1-form $K^\\flat$ and the spray operator $\\delta$ with the Finsler non-linear connection. $K^\\flat$ is related to the generalization of Killing tensors on Finsler manifold, and the condition $\\delta K^\\flat =0$ gives an analytical method of finding higher derivative conserved quantities, which may be called hidden conserved quantities. We show two examples: the Carter constant on Kerr spacetime and the Runge-Lentz vectors in Newtonian gravity.
Gauss law and symmetry restoration
International Nuclear Information System (INIS)
The authors study the restoration of global symmetries of lattice QCD at finite temperature and chemical potential for an arbitrary number of colors Nc and flavors Nf. The Hamiltonian in the Ao gauge has to be supplemented by the Gauss law constraint, that thermal excitations must satisfy. The authors study the problem in the strong-coupling limit and in a Bogoliubov approximation. The free energy to be minimized must be defined by traces over states restricted in the color singlet Hilbert space at each lattice site
Czech Academy of Sciences Publication Activity Database
Kuběna, Aleš Antonín; Franek, P.
Berlin : Springer, 2013, s. 159-170. ISBN 978-3-642-41391-9. ISSN 0302-9743. - (Lecture Notes in Computer Science. 8146). [Symposium of Algorithmic Game Theory . Aachen (DE), 21.10.2013-25.10.2013] R&D Projects: GA MŠk OC10048; GA ČR(CZ) GBP402/12/G097 Institutional support: RVO:67985556 Keywords : Cooperative game * Shapley value * Group theory * Equity * Symmetry * Quasi value Subject RIV: BA - General Mathematics http://library.utia.cas.cz/separaty/2013/E/kubena-0398169.pdf
Symmetries and Dirac equation solutions
International Nuclear Information System (INIS)
The purpose of this thesis is the extension to be relativistic case of a method that has proved useful for the solution of various potential problems in non relativistic situation. This method, the method of dynamical symmetries, is based on the Baker-Campbell-Hausdorf formulae and developed first for the particular example of the relativistic Coulomb problem. Here we generalize the method for a Hamiltonian that can be written as a linear combination of generators of the SO(2,1) group. As illustrative examples, we solve the problem of a charged particle in a constant magnetic field and the exponential magnetic field. (author). 21 refs
History of electroweak symmetry breaking
Kibble, T. W. B.
2015-07-01
In this talk, I recall the history of the development of the unified electroweak theory, incorporating the symmetry-breaking Higgs mechanism, as I saw it from my standpoint as a member of Abdus Salam's group at Imperial College. I start by describing the state of physics in the years after the Second World War, explain how the goal of a unified gauge theory of weak and electromagnetic interactions emerged, the obstacles encountered, in particular the Goldstone theorem, and how they were overcome, followed by a brief account of more recent history, culminating in the historic discovery of the Higgs boson in 2012.
Spontaneous Breaking of Flavor Symmetry
Törnqvist, N A
1996-01-01
It is shown that part of the quark masses of the standard model can be generated spontaneously within the strong interactions of QCD. After the breaking of U(Nf) x U(Nf) symmetry by the vacuum, also the resulting flavor symmetric, degenerate meson mass spectrum is shown to be unstable with respect to quantum loops, for rather general models. For a C-degenerate meson spectrum the stable mass spectrum obeys the Okubo-Zweig-Iizuka rule and the approximateequal spacing rule.
Weigert, S
2006-01-01
A fundamental problem in the theory of PT-invariant quantum systems is to determine whether a given system `respects' this symmetry or not. If not, the system usually develops non-real eigenvalues. It is shown in this contribution how to algorithmically detect the existence of complex eigenvalues for a given PT-symmetric matrix. The procedure uses classical results from stability theory which qualitatively locate the zeros of real polynomials in the complex plane. The interest and value of the present approach lies in the fact that it avoids diagonalization of the Hamiltonian at hand.
Energy Technology Data Exchange (ETDEWEB)
Weigert, Stefan [Department of Mathematics, University of York, Heslington, York YO10 5DD (United Kingdom)
2006-08-11
A fundamental problem in the theory of PT-invariant quantum systems is to determine whether a given system 'respects' this symmetry or not. If not, the system usually develops non-real eigenvalues. It is shown in this contribution how to algorithmically detect the existence of complex eigenvalues for a given PT-symmetric matrix. The procedure uses classical results from stability theory which qualitatively locate the zeros of real polynomials in the complex plane. The interest and value of the present approach lies in the fact that it avoids diagonalization of the Hamiltonian at hand.
Fearful symmetry in aposematic plants
Lev-Yadun, Simcha
2011-01-01
Symmetry has been proposed to increase the efficiency of visual aposematic displays in animals, and I suggest that it may also be true for many aposematic spiny or poisonous plants. For instance, in the very spiny plant taxa cacti, Aloe sp., Agave sp. and Euphorbia sp., which have been proposed to be aposematic because of their colorful spine system, the shoots, and in cacti, the spiny fruits as well, are usually radially symmetric. Moreover, in the radial symmetric shoots of Agave and Aloe t...
New Symmetries of Massless QED
He, Temple; Porfyriadis, Achilleas P; Strominger, Andrew
2014-01-01
An infinite number of physically nontrivial symmetries are found for abelian gauge theories with massless charged particles. They are generated by large $U(1)$ gauge transformations that asymptotically approach an arbitrary function $\\varepsilon(z,\\bar{z})$ on the conformal sphere at future null infinity ($\\mathscr I^+$) but are independent of the retarded time. The value of $\\varepsilon$ at past null infinity ($\\mathscr I^-$) is determined from that on $\\mathscr I^+$ by the condition that it take the same value at either end of any light ray crossing Minkowski space. The $\\varepsilon\
Hidden symmetry in quantum nanostructures
International Nuclear Information System (INIS)
Full text: (author)The theoretical investigation of the hidden symmetries influence on the optical properties of the quantum nanostructures is presented. The problems connected with the parabolic approximation of the confinement potential of the system, as well as two-dimensional Coulomb problem on the character of optical transitions in semiconductor nanostructures are discussed. In particular excitonic absorption in quantum filma and character of arrangement of absorption peak depending on the principal quantum number of the two-dimensional Coulombic problem is also discussed
Progress in Electroweak Symmetry Breaking
Dawson, S
2015-01-01
In this talk, I discuss theoretical advances in understanding the properties of the Higgs boson and the implications for models of electroweak symmetry breaking. I begin by reviewing some of the recent progress in Standard Model calculations for Higgs boson production and decay rates, followed by a lightning tour of the use of effective field theories in the search for new physics in the Higgs sector. I end with a discussion of the complementarity of precision Higgs coupling measurements and direct searches for heavy particles for the discovery of Beyond the Standard Model physics in the electroweak sector.
NONLOCAL SYMMETRIES PAST, PRESENT AND FUTURE
Directory of Open Access Journals (Sweden)
K Andriopoulos
2007-04-01
Full Text Available Nonlocal symmetries entered the literature in the Eighties of the last century largely through the work of Peter Olver. It was observed that there could be gain of symmetry in the reduction of order of an ordinary differential equation. Subsequently the reverse process was also observed. In each case the source of the ‘new’ symmetry was a nonlocal symmetry, ie a symmetry with one or more of the coefficient functions containing an integral. A considerable number of different examples and occurrences were reported by Abraham-Shrauner and Guo in the early Nineties. The role of nonlocal symmetries in the integration, indeed integrability, of differential equationswas excellently illustrated by Abraham-Shrauner, Govinder and Leachwith the equation yy00 − y02 + f0(xyp+2 + pf(xy0yp+1 = 0 which had been touted as a trivially integrable equation devoid of any point symmetry. Further theoretical contributions were made by Govinder, Feix, Bouquet, Geronimi and others in the second half of the Nineties. This included their role in reduction of order using the nonnormal subgroup. The importance of nonlocal symmetries was enhanced by the work of Krause on the Complete Symmetry Group of the Kepler Problem. Krause’s work was furthered by Nucci and there has been considerable development of the use of nonlocal symmetries by Nucci, Andriopoulos, Cotsakis and Leach. The determination of the Complete Symmetry Group for integrable systems such as the simplest version of the Ermakov equation, y00 = y−3, which possesses the algebra sl(2,R has proven to be highly nontrivial and requires some nonintuitive nonlocal symmetries. The determination of the nonlocal symmetries required to specify completely the differential equations of nonintegrableand/or chaotic systems remains largely an open question.
Chiral symmetry in hadron physics methods and ideas of chiral symmetry
International Nuclear Information System (INIS)
Methods and ideas of chiral symmetry is presented based on a lecture note to help the future researches in hadron dynamics along with the chiral symmetry. The chiral symmetry was originally developed as the symmetry between currents before the discovery of QCD. It has come to be understood in principle by now that the symmetry is spontaneously broken and only the part of flavor symmetry remains explicitly. In QCD, however, the chiral symmetry has come to be regarded as the base of the symmetry of the global flavor space of quarks. One of the recent topics of the lattice gauge theory is how the hadron properties will change when the broken symmetry is going to be restored. Since the chiral symmetry is global, it is different from gauge symmetry which is local. It explains the degeneracy of hadron masses and relations between the elements of S-matrix in which same number of particles are included. In practice, however, the symmetry of the axial part is spontaneously broken and pions which behave like gauge particles come to play. Chiral symmetry is defined as the (internal) flavor symmetry for the two independent chirality states of quarks. It discriminates two different fundamental quarks defined for the Lorentz groups O(4) - SL(2, C). The symmetry transformation itself is, however, different from the chirality. They should not be confused. In this lecture note, fundamental properties of pions are described on the basis of the interaction with nucleons at first. General properties of the chiral symmetry and some of the low energy theorems on current algebra are introduced. Then, linear sigma model and nonlinear sigma model are introduced. Then the Skyrme-model, which provides an idea as important as quarks, is explained. One of the interesting topics at present is to restore the broken axial symmetry experimentally to investigate the mechanism of symmetry breaking. (S. Funahashi)
Flavor symmetries and fermion masses
International Nuclear Information System (INIS)
We introduce several ways in which approximate flavor symmetries act on fermions and which are consistent with observed fermion masses and mixings. Flavor changing interactions mediated by new scalars appear as a consequence of approximate flavor symmetries. We discuss the experimental limits on masses of the new scalars, and show that the masses can easily be of the order of weak scale. Some implications for neutrino physics are also discussed. Such flavor changing interactions would easily erase any primordial baryon asymmetry. We show that this situation can be saved by simply adding a new charged particle with its own asymmetry. The neutrality of the Universe, together with sphaleron processes, then ensures a survival of baryon asymmetry. Several topics on flavor structure of the supersymmetric grand unified theories are discussed. First, we show that the successful predictions for the Kobayashi-Maskawa mixing matrix elements, Vub/Vcb = √mu/mc and Vtd/Vts = √md/ms, are a consequence of a large class of models, rather than specific properties of a few models. Second, we discuss how the recent observation of the decay β → sγ constrains the parameter space when the ratio of the vacuum expectation values of the two Higgs doublets, tanΒ, is large. Finally, we discuss the flavor structure of proton decay. We observe a surprising enhancement of the branching ratio for the muon mode in SO(10) models compared to the same mode in the SU(5) model
Superconformal symmetry, NMSSM, and inflation
International Nuclear Information System (INIS)
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 μ 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.
Flavor Symmetry and Grand Unification
Stech, Berthold
2010-01-01
The combination of flavor symmetries with grand unification is considered: GUT $ \\times$ flavor . To accommodate three generations the flavor group SO(3) is used. All fermions transform as 3-vectors under this group. The Yukawa couplings are obtained from vacuum expectation values of flavon fields. For the flavon fields (singlets with respect to the GUT group) and the Higgs fields (singlets with respect to the generation group) a simple form for the effective potentials is postulated. It automatically leads to spontaneous symmetry breaking for these scalar fields. Discrete S4 transformations relate the different locations of the minima of the potentials.These potentials can be used to describe the hierarchy of the well known up quark mass spectrum. Also the huge hierarchy of the masses of the Higgs fields in grand unified models can be parametrized in this way. It leads to a prediction of the mass of the lightest Higgs boson in terms of its vacuum expectation value $v_0$: $ m_{Higgs} = \\frac{v_0}{\\sqrt{2}} = ...
Directory of Open Access Journals (Sweden)
Julian Heeck
2014-12-01
Full Text Available The difference between baryon number B and lepton number L is the only anomaly-free global symmetry of the Standard Model, easily promoted to a local symmetry by introducing three right-handed neutrinos, which automatically make neutrinos massive. The non-observation of any (B–L-violating processes leads us to scrutinize the case of unbroken gauged B–L; besides Dirac neutrinos, the model contains only three parameters, the gauge coupling strength g′, the Stückelberg mass MZ′, and the kinetic mixing angle χ. The new force could manifest itself at any scale, and we collect and derive bounds on g′ over the entire testable range MZ′=0–1013 eV, also of interest for the more popular case of spontaneously broken B–L or other new light forces. We show in particular that successful Big Bang nucleosynthesis provides strong bounds for masses 10 eV
Introduction to Electroweak Symmetry Breaking
Energy Technology Data Exchange (ETDEWEB)
Dawson,S.
2008-10-02
The Standard Model (SM) is the backbone of elementary particle physics-not only does it provide a consistent framework for studying the interactions of quark and leptons, but it also gives predictions which have been extensively tested experimentally. In these notes, I review the electroweak sector of the Standard Model, discuss the calculation of electroweak radiative corrections to observables, and summarize the status of SM Higgs boson searches. Despite the impressive experimental successes, however, the electroweak theory is not completely satisfactory and the mechanism of electroweak symmetry breaking is untested. I will discuss the logic behind the oft-repeated statement: 'There must be new physics at the TeV scale'. These lectures reflect my strongly held belief that upcoming results from the LHC will fundamentally change our understanding of electroweak symmetry breaking. In these lectures, I review the status of the electroweak sector of the Standard Model, with an emphasis on the importance of radiative corrections and searches for the Standard Model Higgs boson. A discussion of the special role of the TeV energy scale in electroweak physics is included.
Spinor Structure and Internal Symmetries
Varlamov, V. V.
2015-10-01
Spinor structure and internal symmetries are considered within one theoretical framework based on the generalized spin and abstract Hilbert space. Complex momentum is understood as a generating kernel of the underlying spinor structure. It is shown that tensor products of biquaternion algebras are associated with the each irreducible representation of the Lorentz group. Space-time discrete symmetries P, T and their combination PT are generated by the fundamental automorphisms of this algebraic background (Clifford algebras). Charge conjugation C is presented by a pseudoautomorphism of the complex Clifford algebra. This description of the operation C allows one to distinguish charged and neutral particles including particle-antiparticle interchange and truly neutral particles. Spin and charge multiplets, based on the interlocking representations of the Lorentz group, are introduced. A central point of the work is a correspondence between Wigner definition of elementary particle as an irreducible representation of the Poincaré group and SU(3)-description (quark scheme) of the particle as a vector of the supermultiplet (irreducible representation of SU(3)). This correspondence is realized on the ground of a spin-charge Hilbert space. Basic hadron supermultiplets of SU(3)-theory (baryon octet and two meson octets) are studied in this framework. It is shown that quark phenomenologies are naturally incorporated into presented scheme. The relationship between mass and spin is established. The introduced spin-mass formula and its combination with Gell-Mann-Okubo mass formula allows one to take a new look at the problem of mass spectrum of elementary particles.
Chiral symmetry breaking and monopoles
Di Giacomo, Adriano; Pucci, Fabrizio
2015-01-01
To understand the relation between the chiral symmetry breaking and monopoles, the chiral condensate which is the order parameter of the chiral symmetry breaking is calculated in the $\\overline{\\mbox{MS}}$ scheme at 2 [GeV]. First, we add one pair of monopoles, varying the monopole charges $m_{c}$ from zero to four, to SU(3) quenched configurations by a monopole creation operator. The low-lying eigenvalues of the Overlap Dirac operator are computed from the gauge links of the normal configurations and the configurations with additional monopoles. Next, we compare the distributions of the nearest-neighbor spacing of the low-lying eigenvalues with the prediction of the random matrix theory. The low-lying eigenvalues not depending on the scale parameter $\\Sigma$ are compared to the prediction of the random matrix theory. The results show the consistency with the random matrix theory. Thus, the additional monopoles do not affect the low-lying eigenvalues. Moreover, we discover that the additional monopoles increa...
Contact symmetries and Hamiltonian thermodynamics
Energy Technology Data Exchange (ETDEWEB)
Bravetti, A., E-mail: bravetti@correo.nucleares.unam.mx [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de México, A.P. 70-543, 04510 Mexico D.F. (Mexico); Lopez-Monsalvo, C.S., E-mail: cesar.slm@correo.nucleares.unam.mx [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de México, A.P. 70-543, 04510 Mexico D.F. (Mexico); Nettel, F., E-mail: Francisco.Nettel@roma1.infn.it [Dipartimento di Fisica, Università di Roma La Sapienza, P.le Aldo Moro 5, I-00185 Rome (Italy)
2015-10-15
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 analyse 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.
Energy Technology Data Exchange (ETDEWEB)
Heeck, Julian, E-mail: julian.heeck@mpi-hd.mpg.de [Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 16, 69120 Heidelberg (Germany)
2014-12-12
The difference between baryon number B and lepton number L is the only anomaly-free global symmetry of the Standard Model, easily promoted to a local symmetry by introducing three right-handed neutrinos, which automatically make neutrinos massive. The non-observation of any (B–L)-violating processes leads us to scrutinize the case of unbroken gauged B–L; besides Dirac neutrinos, the model contains only three parameters, the gauge coupling strength g{sup ′}, the Stückelberg mass M{sub Z{sup ′}}, and the kinetic mixing angle χ. The new force could manifest itself at any scale, and we collect and derive bounds on g{sup ′} over the entire testable range M{sub Z{sup ′}}=0–10{sup 13} eV, also of interest for the more popular case of spontaneously broken B–L or other new light forces. We show in particular that successful Big Bang nucleosynthesis provides strong bounds for masses 10 eV
Dynamical symmetries of the Kepler problem
International Nuclear Information System (INIS)
This paper comes from a first-year undergraduate research project on hidden symmetries of the dynamics for classical Hamiltonian systems. For pedagogical reasons the main subject chosen was Kepler’s problem of motion under a central potential, since it is a completely solved system. It is well known that for this problem the group of dynamical symmetries is strictly larger than the isometry group O(3), the extra symmetries corresponding to hidden symmetries of the dynamics. By taking the point of view of examining the group action of the dynamical symmetries on the allowed trajectories, it is possible to teach the basic elements of many important physics subjects in the same project, including the Hamiltonian formalism, hidden symmetries, integrable systems, group theory and the use of manifolds. (paper)
Dynamics-dependent symmetries in Newtonian mechanics
Holland, Peter
2014-01-01
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.
Dynamical symmetries of the Kepler problem
Cariglia, Marco
2013-01-01
This work originates from a first year undergraduate research project on hidden symmetries of the dynamics for classical Hamiltonian systems, under the program 'Jovens talentos para a Ciencia' of Brazilian funding agency Capes. For pedagogical reasons the main subject chosen was Kepler's problem of motion under a central potential, since it is a completely solved system. It is well known that for this problem the group of dynamical symmetries is strictly larger than the isometry group O(3), the extra symmetries corresponding to hidden symmetries of the dynamics. By taking the point of view of examining the group action of the dynamical symmetries on the allowed trajectories, it is possible to teach in the same project basic elements of as many important subjects in physics as: Hamiltonian formalism, hidden symmetries, integrable systems, group theory, and the use of manifolds.
Hidden gauge symmetry in holomorphic models
Energy Technology Data Exchange (ETDEWEB)
Margalli, Carlos A.; Vergara, J. David, E-mail: vergara@nucleares.unam.mx
2015-10-16
Highlights: • We have found a new gauge symmetry in holomorphic models. • This complex gauge symmetry connects different real systems. • The gauge condition determines the type of hermiticity of the variables. • The procedure is generalizable to any dimension. - Abstract: We study the effect of a hidden gauge symmetry on complex holomorphic systems. For this purpose, we show that intrinsically any holomorphic system has this gauge symmetry. We establish that this symmetry is related to the Cauchy–Riemann equations, in the sense that the associated constraint is a first class constraint only in the case that the potential be holomorphic. As a consequence of this gauge symmetry on the complex space, we can fix the gauge condition in several ways and project from the complex phase-space to real phase space. Different projections are gauge related on the complex phase-space but are not directly related on the real physical phase-space.
Master Symmetry for Holographic Wilson Loops
Klose, Thomas; Munkler, Hagen
2016-01-01
We identify the symmetry underlying the recently observed spectral-parameter transformations of holographic Wilson loops alias minimal surfaces in AdS/CFT. The generator of this nonlocal symmetry is shown to furnish a raising operator on the classical Yangian-type charges of symmetric coset models. We explicitly demonstrate how this master symmetry acts on strong-coupling Wilson loops and indicate a possible extension to arbitrary coupling.
Irregular matrix model with $\\mathcal W$ symmetry
Choi, Sang Kwan
2015-01-01
We present the irregular matrix model which has contains $\\mathcal{W}_3$ and Virasoro symmetry. The irregular matrix model is obtained using the colliding limit of the Toda field theories and produces the inner product between irregular modules of $\\mathcal{W}_3$ symmetry. We evaluate the partition function using the flow equation which is the realization of the Virasoro and $\\mathcal{W}$-symmetry.
Anomalous Mirror Symmetry Generated by Optical Illusion
Directory of Open Access Journals (Sweden)
Kokichi Sugihara
2016-04-01
Full Text Available This paper introduces a new concept of mirror symmetry, called “anomalous mirror symmetry”, which is physically impossible but can be perceived by human vision systems because of optical illusion. This symmetry is characterized geometrically and a method for creating cylindrical surfaces that create this symmetry is constructed. Examples of solid objects constructed by a 3D printer are also shown.
Additional symmetries of supersymmetric KP hierarchies
International Nuclear Information System (INIS)
We investigate the additional symmetries of several supersymmetric KP hierarchies: the SKP hierarchy of Manin and Radul, the SKP2 hierarchy, and the Jacobian SKP hierarchy. In all three cases we find that the algebra of symmetries is isomorphic to the algebra of superdifferential operators, or equivalently SW1+∞. These results seem to suggest that despite their realization depending on the dynamics, the additional symmetries are kinematical in nature. (orig.)
SU(6) Symmetry and its Relativistic Generalizations
International Nuclear Information System (INIS)
1. Origins; 2. The heuristic SU(6) symmetry; 3. Vertex symmetry; 4. Applications of the heuristic formulation; 5. Different languages for SU(6); 6. Attempts at formulations of SU(6) within field theory; 7. Comparison with chiral groups. Possible new limit for exact SU(6) symmetry; 8. A specific model; 9. Decoupling of spin from orbital angular momentum; 10. Realization of SL(4,C) in Hilbert space. Current algebra; 11. Outlook. (author)
"Statistical" symmetry with applications to phase transitions
Birman, Joseph L.; Trebin, Hans-Rainer
1985-01-01
Hermann proposed that mesomorphic media should be classified by assigning certain "statistical symmetry groups" to each possible partially ordered array. Two translational groups introduced were called superordinate and subordinate. We find that the average density in such a partially ordered medium has the superordinate symmetry ℒ1, while the pair correlation function has the subordinate symmetry ℒ2. A complete listing is made of all compatible combinations of ℒ1 and ℒ...
Symmetry adaptation in two-photon spectroscopy
International Nuclear Information System (INIS)
Symmetry adaptation techniques are applied to the determination of the intensity of two-photon transitions for transition ions in finite symmetry environments. The case of intra-configurational transitions are discussed with some details and some results on inter-configurational transitions are briefly reported. In particular, for intra-configurational transitions, a model is described which takes into account the following ingredients: (symmetry, second- plus third-order mechanisms, S-, L- and J-mixings). (author) 20 refs
Mutual information and spontaneous symmetry breaking
Hamma, A.; Giampaolo, S. M.; Illuminati, F.
2015-01-01
We show that the metastable, symmetry-breaking ground states of quantum many-body Hamiltonians have vanishing quantum mutual information between macroscopically separated regions, and are thus the most classical ones among all possible quantum ground states. This statement is obvious only when the symmetry-breaking ground states are simple product states, e.g. at the factorization point. On the other hand, symmetry-breaking states are in general entangled along the entire ordered phase, and t...
Galileo symmetries in polymer particle representation
International Nuclear Information System (INIS)
To illustrate the conceptual problems for the low-energy symmetries in the continuum of spacetime emerging from the discrete quantum geometry, Galileo symmetries are investigated in the polymer particle representation of a non-relativistic particle as a simple toy model. The complete Galileo transformations (translation, rotation and Galileo boost) are naturally defined in the polymer particle Hilbert space and Galileo symmetries are recovered with highly suppressed deviations in the low-energy regime from the underlying polymer particle description
Symmetry Principles of the Unified Field Theory
Gowan, J A
1999-01-01
The addition of symmetry conservation to the principles of the first and second laws of thermodynamics is seen as a key step in the formulation of a conceptually complete unified field theory. The charges of matter are viewed as the symmetry debts of light, the forces they generate as demands for payment. Hence charge conservation = symmetry conservation. The nature of these symmetry debts is identified for each force and the unity of forces traced to their common origin in a primordial symmetric state of light and spacetime.
Symmetries in Images on Ancient Seals
Sparavigna, Amelia
2008-01-01
In this paper, we discuss the presence of symmetries in images engraved on ancient seals, in particular on stamp seals. Mainly used to secure the containers from tampering and for owner's identification, these objects appeared during the 5th millennium BC in Mesopotamia. Usually the seals were engraved with simple images, suitable to communicate an immediate information. Rotational symmetries are already displayed by the most ancient stamp seals, whose images reach a quasi-perfect symmetry in their small circular or ovoid spaces. Bilateral symmetries are quite common in Egyptian scarab seals.
Symmetry analysis of differential equations an introduction
Arrigo, Daniel J
2015-01-01
A self-contained introduction to the methods and techniques of symmetry analysis used to solve ODEs and PDEsSymmetry Analysis of Differential Equations: An Introduction presents an accessible approach to the uses of symmetry methods in solving both ordinary differential equations (ODEs) and partial differential equations (PDEs). Providing comprehensive coverage, the book fills a gap in the literature by discussing elementary symmetry concepts and invariance, including methods for reducing the complexity of ODEs and PDEs in an effort to solve the associated problems. Thoroughly class-tested, t
A K3 sigma model with : symmetry
Gaberdiel, Matthias R.; Taormina, Anne; Volpato, Roberto; Wendland, Katrin
2014-02-01
The K3 sigma model based on the -orbifold of the D 4-torus theory is studied. It is shown that it has an equivalent description in terms of twelve free Majorana fermions, or as a rational conformal field theory based on the affine algebra . By combining these different viewpoints we show that the = (4 , 4) preserving symmetries of this theory are described by the discrete symmetry group : . This model therefore accounts for one of the largest maximal symmetry groups of K3 sigma models. The symmetry group involves also generators that, from the orbifold point of view, map untwisted and twisted sector states into one another.
Restoration of Chiral Symmetry in Excited Hadrons
International Nuclear Information System (INIS)
Physics of the low-lying and high-lying hadrons in the light flavor sector is reviewed. While the low-lying hadrons are strongly affected by the spontaneous breaking of chiral symmetry, in the high-lying hadrons the chiral symmetry is restored. A manifestation of the chiral symmetry restoration in excited hadrons is a persistence of the chiral multiplet structure in both baryon and meson spectra. Meson and baryon chiral multiplets are classified. A relation between the chiral symmetry restoration and the string picture of excited hadrons is discussed. (author)
Symmetry energy in nuclear density functional theory
International Nuclear Information System (INIS)
The nuclear symmetry energy represents a response to the neutron-proton asymmetry. In this paper 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. (orig.)
Fake Conformal Symmetry in Unimodular Gravity
Oda, Ichiro
2016-01-01
We study Weyl symmetry (local conformal symmetry) in unimodular gravity. It is shown that the Noether currents for both Weyl symmetry and global scale symmetry, identically vanish as in the conformally invariant scalar-tensor gravity. We clearly explain why in the class of conformally invariant gravitational theories, the Noether currents vanish by starting with the conformally invariant scalar-tensor gravity. Moreover, we comment on both classical and quantum-mechanical equivalences among Einstein's general relativity, the conformally invariant scalar-tensor gravity and the Weyl-transverse (WTDiff) gravity. Finally, we discuss the Weyl current in the conformally invariant scalar action and see that it is also vanishing.
Symmetry, Wigner functions and particle reactions
International Nuclear Information System (INIS)
We consider the great principle of physics - symmetry - and some ideas, connected with it, suggested by a great physicist Eugene Wigner. We will discuss the concept of symmetry and spin, study the problem of separation of kinematics and dynamics in particle reactions. Using Wigner rotation functions (reflecting symmetry properties) in helicity amplitude decomposition and crossing-symmetry between helicity amplitudes (which contains the same Wigner functions) we get convenient general formalism for description of reactions between particles with any masses and spins. We also consider some applications of the formalism. 17 refs., 1 tab
Dryzun, Chaim; Avnir, David
2009-11-14
In this paper we generalize a method for evaluating the continuous symmetry measure, which is a quantitative estimate of the degree of symmetry of a given object. The generalization makes it possible to calculate the degree of symmetry content for any mathematical entity that is part of metric spaces such as vectors, matrices, operators and functions. Furthermore, by this new approach one can calculate the symmetry-content values for any compact symmetry groups either finite or infinite. An advantage of the new methodology is the ability to investigate analytically problems of symmetry changes. Examples of symmetry evaluation calculations are provided, including mixing of ideal gases, evaluation of the symmetry content of a Hamiltonian operator, the 2p(z) orbital of the hydrogen atom, and more. PMID:19851543
Flavour symmetry as a Spontaneously Broken Discrete Permutation Symmetry Embedded in Colour
Törnqvist, N A
1999-01-01
A new mechanism for breaking an internal symmetry spontaneously is discussed, which is intermediate between the Nambu-Goldstone and Wigner modes of symmetry breaking. Here the quark-antiquark sea takes the role of the vacuum of the Nambu-Goldstone case. Flavour symmetry becomes a discrete permutation symmetry of the valence quarks with respect to the sea quarks, which can be spontaneously broken without generation of massless Goldstone bosons.
Beyond bilateral symmetry: geometric morphometric methods for any type of symmetry
Klingenberg Christian; Savriama Yoland
2011-01-01
Abstract Background Studies of symmetric structures have made important contributions to evolutionary biology, for example, by using fluctuating asymmetry as a measure of developmental instability or for investigating the mechanisms of morphological integration. Most analyses of symmetry and asymmetry have focused on organisms or parts with bilateral symmetry. This is not the only type of symmetry in biological shapes, however, because a multitude of other types of symmetry exists in plants a...
Electroweak Symmetry Breaking by QCD
Kubo, Jisuke; Lindner, Manfred
2014-01-01
We propose a new mechanism to generate the electroweak scale within the framework of QCD, which is extended to include conformally invariant scalar degrees of freedom belonging to a larger irreducible representation of $SU(3)_c$. The electroweak symmetry breaking is triggered dynamically via the Higgs portal by the condensation of the colored scalar field around $1$ TeV. The mass of the colored boson is restricted to be $350$ GeV $\\lesssim m_S\\lesssim 3$ TeV, with the upper bound obtained from renormalization group evolution. This implies that the colored boson can be produced at LHC. If the colored boson is electrically charged, the branching fraction of the Higgs decaying into two photons can slightly increase, and moreover, it can be produced at future linear colliders.
Symmetry violations and rare decays
International Nuclear Information System (INIS)
This constitutes the report of the working group on symmetry violations and rare decays. The next generation of CP violating kaon decay experiments (the 2π and π0e+e- modes) were considered at the Tevatron and at the proposed Main Injector, effectively building upon the work of the earlier Fermilab Workshop on Physics at the Main Injector. The optimizations for the electromagnetic calorimeter and for background rejection are treated in some detail. Very precise CPT tests in the 2π decay modes are also treated. A sensitive experiment looking for flavor violation at the Main Injector (KL → μe) is discussed. The significant advantages of possible stretcher and prebooster rings are mentioned. 27 refs., 5 figs., 3 tabs
International Nuclear Information System (INIS)
We propose a novel SU(3)c×SU(2)L×SU(2)R×U(1)B-L left-right symmetric model where the standard model fermion and Higgs fields are SU(2)L doublets or SU(2) singlets while their mirror partners are SU(2)R doublets or SU(2) singlets. The scalar fields also include a real singlet for dark matter and two SU(2) triplets for seesaw. The mixing between the standard model and mirror fermions is forbidden by a Z2×Z2′ discrete symmetry. The mirror charged fermions can decay into their standard model partners with the dark-matter scalar while the mirror neutrinos can decay into the mirror charged fermions through the right-handed gauge interactions. Our model can have new implications on the strong CP problem, leptogenesis, collider phenomenology and dark matter detection.
Wormhole dynamics in spherical symmetry
International Nuclear Information System (INIS)
A dynamical theory of traversable wormholes is detailed in spherical symmetry. Generically a wormhole consists of a tunnel of trapped surfaces between two mouths, defined as temporal outer trapping horizons with opposite senses, in mutual causal contact. In static cases, the mouths coincide as the throat of a Morris-Thorne wormhole, with surface gravity providing an invariant measure of the radial curvature or ''flaring-out''. The null energy condition must be violated at a wormhole mouth. Zeroth, first, and second laws are derived for the mouths, as for black holes. Dynamic processes involving wormholes are reviewed, including enlargement or reduction, and interconversion with black holes. A new area of wormhole thermodynamics is suggested.
Renormalizable theories with symmetry breaking
Becchi, Carlo M
2016-01-01
The description of symmetry breaking proposed by K. Symanzik within the framework of renormalizable theories is generalized from the geometrical point of view. For an arbitrary compact Lie group, a soft breaking of arbitrary covariance, and an arbitrary field multiplet, the expected integrated Ward identities are shown to hold to all orders of renormalized perturbation theory provided the Lagrangian is suitably chosen. The corresponding local Ward identity which provides the Lagrangian version of current algebra through the coupling to an external, classical, Yang-Mills field, is then proved to hold up to the classical Adler-Bardeen anomaly whose general form is written down. The BPHZ renormalization scheme is used throughout in such a way that the algebraic structure analyzed in the present context may serve as an introduction to the study of fully quantized gauge theories.
Supergravity backgrounds and symmetry superalgebras
Ertem, Ümit
2016-01-01
We consider the bosonic sectors of supergravity theories in ten and eleven dimensions which correspond to the low energy limits of string theories and M-theory. The solutions of supergravity field equations are known as supergravity backgrounds and the number of preserved supersymmetries in those backgrounds are determined by Killing spinors. We provide some examples of supergravity backgrounds which preserve different fractions of supersymmetry. An important invariant for the characterization of supergravity backgrounds is their Killing superalgebras which are constructed out of Killing vectors and Killing spinors of the background. After constructing Killing superalgebras of some special supergravity backgrounds, we discuss about the possibilities of the extensions of these superalgebras to include the higher degree hidden symmetries of the background.
Wormhole dynamics in spherical symmetry
Hayward, Sean A
2009-01-01
A dynamical theory of traversable wormholes is detailed in spherical symmetry. Generically a wormhole consists of a tunnel of trapped surfaces between two mouths, defined as temporal outer trapping horizons with opposite senses, in mutual causal contact. In static cases, the mouths coincide as the throat of a Morris-Thorne wormhole, with surface gravity providing an invariant measure of the radial curvature or "flaring-out". The null energy condition must be violated at a wormhole mouth. Zeroth, first and second laws are derived for the mouths, as for black holes. Dynamic processes involving wormholes are reviewed, including enlargement or reduction, and interconversion with black holes. A new area of wormhole thermodynamics is suggested.
Neutrino properties and fundamental symmetries
International Nuclear Information System (INIS)
This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). There are two components to this work. The first is a development of a new detection scheme for neutrinos. The observed deficit of neutrinos from the Sun may be due to either a lack of understanding of physical processes in the Sun or may be due to neutrinos oscillating from one type to another during their transit from the Sun to the Earth. The Sudbury Neutrino Observatory (SNO) is designed to use a water Cerenkov detector employing one thousand tonnes of heavy water to resolve this question. The ability to distinguish muon and tau neutrinos from electron neutrinos is crucial in order to carry out a model-independent test of neutrino oscillations. We describe a developmental exploration of a novel technique to do this using 3He proportional counters. Such a method offers considerable advantages over the initially proposed method of using Cerenkov light from capture on NaCl in the SNO. The second component of this work is an exploration of optimal detector geometry for a time-reversal invariance experiment. The question of why time moves only in the forward direction is one of the most puzzling problems in modern physics. We know from particle physics measurements of the decay of kaons that there is a charge-parity symmetry that is violated in nature, implying time-reversal invariance violation. Yet, we do not understand the origin of the violation of this symmetry. To promote such an understanding, we are developing concepts and prototype apparatus for a new, highly sensitive technique to search for time-reversal-invariance violation in the beta decay of the free neutron. The optimized detector geometry is seven times more sensitive than that in previous experiments. 15 refs
SURFACE SYMMETRY RESOLUTION OF NONLINEAR OPTICAL TECHNIQUES
KOOPMANS, B; VANDERWOUDE, F; SAWATZKY, GA
1992-01-01
A general rule is derived, relating the order of a nonlinear optical process to the highest possible symmetry which can be resolved in a rotational analysis. We show that with an Nth order optical technique, rotational anisotropy can be observed only up to (N + L)-fold rotational symmetry, where L i
Symmetry and resonance in periodic FPU chains
Rink, B.
2001-01-01
The symmetry and resonance properties of the Fermi Pasta Ulam chain with periodic boundary conditions are exploited to construct a nearidentity transformation bring ing this Hamiltonian system into a particularly simple form This BirkhoGustavson normal form retains the symmetries of the original sy
Nuclear symmetry energy: An experimental overview
Shetty, D. V.; Yennello, S. J.
2010-01-01
The nuclear symmetry energy is a fundamental quantity important for studying the structure of systems as diverse as the atomic nucleus and the neutron star. Considerable efforts are being made to experimentally extract the symmetry energy and its dependence on nuclear density and temperature. In this article, we review experimental studies carried out up-to-date and their current status.
Spontaneous symmetry breakdown in gauge theories
International Nuclear Information System (INIS)
The dynamical theory of spontaneous breakdown correctly predicts the bound states and relates the order parameters of electron-photon superconductivity and quark-gluon chiral symmetry. A similar statement cannot be made for the standard electro-weak gauge symmetry. (author)
Discrete symmetries and their stringy origin
International Nuclear Information System (INIS)
Discrete symmetries have proven to be very useful in controlling the phenomenology of theories beyond the standard model. In this work we explore how these symmetries emerge from string compactifications. Our approach is twofold: On the one hand, we consider the heterotic string on orbifold backgrounds. In this case the discrete symmetries can be derived from the orbifold conformal field theory, and it can be shown that they are in close relation with the orbifold geometry. We devote special attention to R-symmetries, which arise from discrete remnants of the Lorentz group in compact space. Further we discuss the physical implications of these symmetries both in the heterotic mini-landscape and in newly constructed models based on the Z2 x Z4 orbifold. In both cases we observe that the discrete symmetries favor particular locations in the orbifold where the particles of standard model should live. On the other hand we consider a class of F-theory models exhibiting an SU(5) gauge group, times additional U(1) symmetries. In this case, the smooth compactification background does not permit us to track the discrete symmetries as transparently as in orbifold models. Hence, we follow a different approach and search for discrete subgroups emerging after the U(1)s are broken. We observe that in this approach it is possible to obtain the standard Z2 matter parity of the MSSM.
Electroweak Symmetry Breaking and the Higgs Boson
Pich, Antonio
2015-01-01
The first LHC run has confirmed the Standard Model as the correct theory at the electroweak scale, and the existence of a Higgs-like particle associated with the spontaneous breaking of the electroweak gauge symmetry. These lectures overview the present knowledge on the Higgs boson and discuss alternative scenarios of electroweak symmetry breaking which are already being constrained by the experimental data.
Hidden flavor symmetries of SO(10) GUT
Bajc, Borut
2016-01-01
The Yukawa interactions of the SO(10) GUT with fermions in 16-plets (as well as with singlets) have certain intrinsic ("built-in") symmetries which do not depend on the model parameters. Thus, the symmetric Yukawa interactions of the 10 and 126 dimensional Higgses have intrinsic discrete $Z_2\\times Z_2$ symmetries, while the antisymmetric Yukawa interactions of the 120 dimensional Higgs have a continuous SU(2) symmetry. The couplings of SO(10) singlet fermions with fermionic 16-plets have $U(1)^3$ symmetry. We consider a possibility that some elements of these intrinsic symmetries are the residual symmetries, which originate from the (spontaneous) breaking of a larger symmetry group $G_f$. Such an embedding leads to the determination of certain elements of the relative mixing matrix $U$ between the matrices of Yukawa couplings $Y_{10}$, $Y_{126}$, $Y_{120}$, and consequently, to restrictions of masses and mixings of quarks and leptons. We explore the consequences of such embedding using the symmetry group con...
Hidden flavor symmetries of SO(10) GUT
Bajc, Borut; Smirnov, Alexei Yu.
2016-08-01
The Yukawa interactions of the SO(10) GUT with fermions in 16-plets (as well as with singlets) have certain intrinsic ("built-in") symmetries which do not depend on the model parameters. Thus, the symmetric Yukawa interactions of the 10 and 126 dimensional Higgses have intrinsic discrete Z2 ×Z2 symmetries, while the antisymmetric Yukawa interactions of the 120 dimensional Higgs have a continuous SU(2) symmetry. The couplings of SO(10) singlet fermions with fermionic 16-plets have U(1) 3 symmetry. We consider a possibility that some elements of these intrinsic symmetries are the residual symmetries, which originate from the (spontaneous) breaking of a larger symmetry group Gf. Such an embedding leads to the determination of certain elements of the relative mixing matrix U between the matrices of Yukawa couplings Y10, Y126, Y120, and consequently, to restrictions of masses and mixings of quarks and leptons. We explore the consequences of such embedding using the symmetry group conditions. We show how unitarity emerges from group properties and obtain the conditions it imposes on the parameters of embedding. We find that in some cases the predicted values of elements of U are compatible with the existing data fits. In the supersymmetric version of SO(10) such results are renormalization group invariant.
Local symmetries of non-expanding horizons
International Nuclear Information System (INIS)
Local symmetries of a non-expanding horizon have been investigated in the first-order formulation of gravity. When applied to spherically symmetric horizons, only a U(1) subgroup of the Lorentz group survives as a residual local symmetry that one can make use of in constructing an effective theory on the horizon. (paper)
Pauli-Guersey symmetry in gauge theories
International Nuclear Information System (INIS)
Gauge theories with massless or massive fermions in a selfcontragredient representation exhibit global symmetries of Pauli-Guersey type. Some of them are broken spontaneously leading to a difermion Goldstone bosons. An example of a boson version of the Pauli-Guersey symmetry is provided by the Weinberg-Salam model in the limit THETAsub(w)→O
Symmetry reduction on non-expanding horizons
International Nuclear Information System (INIS)
Local symmetries of a non-expanding horizon have been investigated in the 1st order formulation of gravity. When applied to a spherically symmetric horizons, only a U(1) subgroup of the Lorentz group survives as residual local symmetry that one can make use of in constructing an effective theory on the horizon
Nuclear symmetry energy: An experimental overview
Indian Academy of Sciences (India)
D V Shetty; S J Yennello
2010-08-01
The nuclear symmetry energy is a fundamental quantity important for studying the structure of systems as diverse as the atomic nucleus and the neutron star. Considerable efforts are being made to experimentally extract the symmetry energy and its dependence on nuclear density and temperature. In this article, the experimental studies carried out up-to-date and their current status are reviewed.
Four Top Production and Electroweak Symmetry Breaking
Cheung, Kingman
1995-01-01
With the recent discovery of a heavy top quark $(m_t \\approx 175 - 200$ GeV), the top quark opens an window to electroweak symmetry breaking. We propose the study of four-top, $t\\bar t t\\bar t$, production at hadronic supercolliders as a probe to electroweak symmetry breaking.
Is chiral symmetry manifested in nuclear structure?
Furnstahl, R. J.; Schwenk, A
2010-01-01
Spontaneously broken chiral symmetry is an established property of low-energy quantum chromodynamics, but finding direct evidence for it from nuclear structure data is a difficult challenge. Indeed, phenomenologically successful energy-density functional approaches do not even have explicit pions. Are there smoking guns for chiral symmetry in nuclei?
Symmetry breaking and restoration in gauge theories
International Nuclear Information System (INIS)
A review is made of the utilization of the Higgs mechanism in spontaneous symmetry breaking. It is shown that such as ideas came from an analogy with the superconductivity phenomenological theory based on a Ginzburg-Landau lagrangean. The symmetry restoration through the temperature influence is studied. (L.C.)
Molecular symmetry in ab initio calculations
International Nuclear Information System (INIS)
A scheme is presented for the construction of the Fock matrix in LCAO-SCF calculations and for the transformation of basis integrals to LCAO-MO integrals that can utilize several symmetry unique lists of integrals corresponding to different symmetry groups. The algorithm is fully compatible with vector processing machines and is especially suited for parallel processing machines. copyright 1987 Academic Press, Inc
Notes on generalized global symmetries in QFT
Energy Technology Data Exchange (ETDEWEB)
Sharpe, Eric [Department of Physics MC 0435, 850 West Campus Drive, Virginia Tech, Blacksburg, VA (United States)
2015-11-15
It was recently argued that quantum field theories possess one-form and higher-form symmetries, labelled 'generalized global symmetries.' In this paper, we describe how those higher-form symmetries can be understood mathematically as special cases of more general 2-groups and higher groups, and discuss examples of quantum field theories admitting actions of more general higher groups than merely one-form and higher-form symmetries. We discuss analogues of topological defects for some of these higher symmetry groups, relating some of them to ordinary topological defects. We also discuss topological defects in cases in which the moduli 'space' (technically, a stack) admits an action of a higher symmetry group. Finally, we outline a proposal for how certain anomalies might potentially be understood as describing a transmutation of an ordinary group symmetry of the classical theory into a 2-group or higher group symmetry of the quantum theory, which we link to WZW models and bosonization. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
de Leeuw, Marius; Moriyama, Sanefumi; Regelskis, Vidas; Torrielli, Alessandro
2012-01-01
We discuss special quantum group (secret) symmetries of the integrable system associated to the AdS/CFT correspondence. These symmetries have by now been observed in a variety of forms, including the spectral problem, the boundary scattering problem, n-point amplitudes, the pure-spinor formulation and quantum affine deformations.
Time-reversal symmetry in nonlinear optics
Trzeciecki, M.; Hübner, W.
2000-01-01
The applicability of time-reversal symmetry to nonlinear optics is discussed, both from macroscopic (Maxwell equations) and microscopic (quantum theoretical) point of view. We find that only spatial operations can be applied for the symmetry classification of nonlinear optical processes in magnetic, in particular antiferromagnetic, materials. An example is given where both operations (time reversal and a spatial operation) can yield different results.
Complex Networks and Symmetry I: A Review
Directory of Open Access Journals (Sweden)
Riccardo Basosi
2010-09-01
Full Text Available In this review we establish various connections between complex networks and symmetry. While special types of symmetries (e.g., automorphisms are studied in detail within discrete mathematics for particular classes of deterministic graphs, the analysis of more general symmetries in real complex networks is far less developed. We argue that real networks, as any entity characterized by imperfections or errors, necessarily require a stochastic notion of invariance. We therefore propose a definition of stochastic symmetry based on graph ensembles and use it to review the main results of network theory from an unusual perspective. The results discussed here and in a companion paper show that stochastic symmetry highlights the most informative topological properties of real networks, even in noisy situations unaccessible to exact techniques.
Tests of Gravitational Symmetries with Radio Pulsars
Shao, Lijing
2016-01-01
Symmetries play important roles in modern theories of physical laws. In this paper, we review several experimental tests of important symmetries associated with the gravitational interaction, including the universality of free fall for self-gravitating bodies, time-shift symmetry in the gravitational constant, local position invariance and local Lorentz invariance of gravity, and spacetime translational symmetries. Recent experimental explorations for post-Newtonian gravity are discussed, of which, those from pulsar astronomy are highlighted. All of these tests, of very different aspects of gravity theories, at very different length scales, favor to very high precision the predictions of the strong equivalence principle (SEP) and, in particular, general relativity which embodies SEP completely. As the founding principles of gravity, these symmetries are motivated to be promoted to even stricter tests in future.
Tests of gravitational symmetries with radio pulsars
Shao, LiJing; Wex, Norbert
2016-09-01
Symmetries play important roles in modern theories of physical laws. In this paper, we review several experimental tests of important symmetries associated with the gravitational interaction, including the universality of free fall for self-gravitating bodies, time-shift symmetry in the gravitational constant, local position invariance and local Lorentz invariance of gravity, and spacetime translational symmetries. Recent experimental explorations for post-Newtonian gravity are discussed, of which, those from pulsar astronomy are highlighted. All of these tests, of very different aspects of gravity theories, at very different length scales, favor to very high precision the predictions of the strong equivalence principle (SEP) and, in particular, general relativity which embodies SEP completely. As the founding principles of gravity, these symmetries are motivated to be promoted to even stricter tests in future.
Low density behaviour of nuclear symmetry energy
International Nuclear Information System (INIS)
The nuclear symmetry energy is a fundamental quantity important for studying the structure of systems as diverse as the atomic nucleus and the neutron star. Considerable efforts have been made to ascertain the symmetry energy and its dependence on nuclear density. The theoretical studies are in agreement in general but differences in detail e.g. at sub- and supra-saturation density. The density behavior of the symmetry energy with respect to charge asymmetric nuclear matter is studied within the density functional derived from Density-Dependent Relativistic Hadron field (DDRH) theory. We explored the genuine contribution of the isovector and isoscalar mesons to the symmetry energy and the isospin dynamics of nuclear matter. The results of our calculation for the isospin dependence of nuclear symmetry energy and the effective pairing interaction in comparison to phenomenological approaches are presented.
Symmetry distribution of cities in China
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The authors of this paper induced five principles of geographical symmetry based on the space distributions of cities and towns in China. There is a symmetry distribution of cities and towns. The symmetry characteristics are the following: (i) the average coordination number of the cities (including large cities, medium cities and county towns) is 6 ( i.g. rotation symmetry); (ii) the distribution of large and medium cities are shown to be the latticework in which two directions are parallel to two main tectonic ones in China, respectively; (iii) the distribution of county towns of a province is also shown to be the latticework in which two directions are parallel to two tectonic ones in this province (i. g. two-dimensional translation ) and (iv) the concentric circle distribution of cities (CCDC) is centered round a large city (i. g. rotation symmetry).
Hojman symmetry in f(T) theory
Wei, Hao; Zhou, Ya-Nan; Li, Hong-Yu; Zou, Xiao-Bo
2015-11-01
Today, f(T) theory has been one of the popular modified gravity theories to explain the accelerated expansion of the universe without invoking dark energy. In this work, we consider the so-called Hojman symmetry in f(T) theory. Unlike Noether conservation theorem, the symmetry vectors and the corresponding conserved quantities in Hojman conservation theorem can be obtained by using directly the equations of motion, rather than Lagrangian or Hamiltonian. We find that Hojman symmetry can exist in f(T) theory, and the corresponding exact cosmological solutions are obtained. We find that the functional form of f(T) is restricted to be the power-law or hypergeometric type, while the universe experiences a power-law or hyperbolic expansion. These results are different from the ones obtained by using Noether symmetry in f(T) theory. Therefore, it is reasonable to find exact cosmological solutions via Hojman symmetry.
Symmetry Breaking in Neuroevolution: A Technical Report
Urfalioglu, Onay
2011-01-01
Artificial Neural Networks (ANN) comprise important symmetry properties, which can influence the performance of Monte Carlo methods in Neuroevolution. The problem of the symmetries is also known as the competing conventions problem or simply as the permutation problem. In the literature, symmetries are mainly addressed in Genetic Algoritm based approaches. However, investigations in this direction based on other Evolutionary Algorithms (EA) are rare or missing. Furthermore, there are different and contradictionary reports on the efficacy of symmetry breaking. By using a novel viewpoint, we offer a possible explanation for this issue. As a result, we show that a strategy which is invariant to the global optimum can only be successfull on certain problems, whereas it must fail to improve the global convergence on others. We introduce the \\emph{Minimum Global Optimum Proximity} principle as a generalized and adaptive strategy to symmetry breaking, which depends on the location of the global optimum. We apply the...
The Perception of Symmetry in Depth: Effect of Symmetry Plane Orientation
Directory of Open Access Journals (Sweden)
Bart Farell
2015-04-01
Full Text Available The visual system is sensitive to symmetries in the frontoparallel plane, and bilateral symmetry about a vertical axis has a particular salience. However, these symmetries represent only a subset of the symmetries realizable in three-dimensional space. The retinal image symmetries formed when viewing natural objects are typically the projections of three-dimensional objects—animals, for example—that have a symmetry in depth. To characterize human sensitivity to depth symmetry, experiments measured observers’ ability to discriminate stereo displays that were symmetrically distributed in depth and those that were asymmetrically distributed. Disparity values were distributed about one of four planes passing through the z-axis and differing in frontoparallel orientation. Asymmetrical patterns were generated by perturbing one of these disparities. Symmetrical-asymmetrical discrimination thresholds were lowest for symmetry about the vertical plane and highest for the horizontal plane. Thresholds for discriminating repetitions and non-repetitions of depth values did not differ across the four planes, whereas discriminations for depth gradients differed from both the symmetry and repetition cases. The heightened sensitivity to symmetry in depth about the vertical plane is a 3-D analog of 2-D mirror-image symmetry performance and could be its source.
Efficient Symmetry Reduction and the Use of State Symmetries for Symbolic Model Checking
Directory of Open Access Journals (Sweden)
Christian Appold
2010-06-01
Full Text Available One technique to reduce the state-space explosion problem in temporal logic model checking is symmetry reduction. The combination of symmetry reduction and symbolic model checking by using BDDs suffered a long time from the prohibitively large BDD for the orbit relation. Dynamic symmetry reduction calculates representatives of equivalence classes of states dynamically and thus avoids the construction of the orbit relation. In this paper, we present a new efficient model checking algorithm based on dynamic symmetry reduction. Our experiments show that the algorithm is very fast and allows the verification of larger systems. We additionally implemented the use of state symmetries for symbolic symmetry reduction. To our knowledge we are the first who investigated state symmetries in combination with BDD based symbolic model checking.
Unified models and unitary symmetry
International Nuclear Information System (INIS)
The experimentally established small size of the space time region where weak interactions occur; ''the weak beg'', is taken as a starting point for a dynamical model for parity violation in weak interactions. It is argued that weakly interacting Dirac bi-spinors behave as massles in the weak beg, and then they split into pairs of decoupled Weyl spinors. As a consequence, any P, C, T conserving gauge Lagrangian in terms of multiplets of Dirac fields will split, in the weak bag, into P and C violating terms representing the weak interactions of the concerned fermions. Following the criterion of maximal simplicity and economy, some SU(N), U(N) symmetruc models are presented. It is shown that (a) Reduction of SU(3) x P, C, T symmetry to SU(2) x U(1) x PC, T for weak interactions is easily obtained by force of chiral projectors. (b) The models are apt to represent all weak and e.m. properties of known leptons and a unified model for weak and e.m. interactions, generalization of the Salam-Weinberg model, emerges with the mixing angle theta depending on N in SU(N). For N=3 the model coincides with the Salam-Weinberg model with theta=30sup(deg). At present experimental data seem to favour the SU(4) model where sin sup(2)theta = 1/3. (c) Absence of ΔS=1 neutral currents can easily be explained already in the frame of SU(3). (d) Integer charges for leptons and fractional charges for quarks can be fitted in appropriate SU(3)-U(3) models. (e) In U(N) symmetric models the resulting q.e.d. presents Pauli-Villars regularization of the self-energy and vertex parts, and the Schwinger-Dyson equations for self-masses are of the Fredholm type as a consequence of the U(N) symmetry and of the neutral currents. The possibility then arises of a full q.e.d. regularization by weak interactions. (f) Neutral current interactions are parity conserving (axial) among charged particles, while parity violating among neutral-charged, neutral-neutral ones in all models presented. A generalized
PREFACE: Symmetries in Science XVI
2014-10-01
This volume of the proceedings ''Symmetries in Science XVI'' is dedicated to the memory of Miguel Lorente and Allan Solomon who both participated several times in these Symposia. We lost not only two great scientists and colleagues, but also two wonderful persons of high esteem whom we will always remember. Dieter Schuch, Michael Ramek There is a German saying ''all good things come in threes'' and ''Symmetries in Science XVI'', convened July 20-26, 2013 at the Mehrerau Monastery, was our third in the sequel of these symposia since taking it over from founder Bruno Gruber who instigated it in 1988 (then in Lochau). Not only the time seemed to have been perfect (one week of beautiful sunshine), but also the medley of participants could hardly have been better. This time, 34 scientists from 16 countries (more than half outside the European Union) came together to report and discuss their latest results in various fields of science, all related to symmetries. The now customary grouping of renowned experts and talented newcomers was very rewarding and stimulating for all. The informal, yet intense, discussions at ''Gasthof Lamm'' occurred (progressively later) each evening till well after midnight and finally till almost daybreak! However, prior to the opening ceremony and during the conference, respectively, we were informed that Miguel Lorente and Allan Solomon had recently passed away. Both attended the SIS Symposia several times and had many friends among present and former participants. Professor Peter Kramer, himself a long-standing participant and whose 80th birthday commemoration prevented him from attending SIS XVI, kindly agreed to write the obituary for Miguel Lorente. Professors Richard Kerner and Carol Penson (both also former attendees) penned, at very short notice, the tribute to Allan Solomon. The obituaries are included in these Proceedings and further tributes have been posted to our conference website. In 28 lectures and an evening poster
Rotating Drops with Helicoidal Symmetry
Palmer, Bennett
2014-01-01
See http://youtu.be/Mf4IE8gWcJs for a YouTube video showing part of the results in this paper. We consider helicoidal immersions in the Euclidean space whose axis of symmetry is the z-axis that are solutions of the equation 2 H=\\Lambda_0-a 1/2 R^2 where H is the mean curvature of the surface, R is the distance form the point in the surface to the z-axis and a is a real number. We refer to these surfaces as helicoidal rotating drops. We prove the existence of properly immersed solutions that contain the z-axis. We also show the existence of several families of embedded examples. We describe the set of possible solutions and we show that most of these solutions are not properly immerse and are dense in the region bounded by two concentric cylinders. We show that all properly immersed solutions, besides being invariant under a one parameter helicoidal group, they are invariant under a cyclic group of rotations of the variables x and y. The second variation of energy for the volume constrained problem with Dirich...
Chlorophylls, Symmetry, Chirality, and Photosynthesis
Directory of Open Access Journals (Sweden)
Mathias O. Senge
2014-09-01
Full Text Available Chlorophylls are a fundamental class of tetrapyrroles and function as the central reaction center, accessory and photoprotective pigments in photosynthesis. Their unique individual photochemical properties are a consequence of the tetrapyrrole macrocycle, the structural chemistry and coordination behavior of the phytochlorin system, and specific substituent pattern. They achieve their full potential in solar energy conversion by working in concert in highly complex, supramolecular structures such as the reaction centers and light-harvesting complexes of photobiology. The biochemical function of these structures depends on the controlled interplay of structural and functional principles of the apoprotein and pigment cofactors. Chlorophylls and bacteriochlorophylls are optically active molecules with several chiral centers, which are necessary for their natural biological function and the assembly of their supramolecular complexes. However, in many cases the exact role of chromophore stereochemistry in the biological context is unknown. This review gives an overview of chlorophyll research in terms of basic function, biosynthesis and their functional and structural role in photosynthesis. It highlights aspects of chirality and symmetry of chlorophylls to elicit further interest in their role in nature.
PREFACE: Symmetries in Science XIV
Schuch, Dieter; Ramek, Michael
2010-04-01
Symmetries Logo This volume of the proceedings "Symmetries in Science XIV" is dedicated to the memory of our colleagues and dear friends Marcos Moshinsky and Yuriĭ Smirnov who regularly participated in these Symposia and were a great inspiration to many. We shall miss them. Dieter Schuch and Michael Ramek The international symposium "Symmetries in Science XIV" held at Collegium Mehrerau in Bregenz, Austria from July 19-24, 2009, attended by 32 scientists from 11 countries, was an experiment, performed by theoreticians. Aim of this experiment was to find out if the desire to revive or even continue this conference series was stronger than the very restricted pecuniary boundary conditions. It obviously was! After its establishment by Bruno Gruber in 1979, the biennial series settled in the very stimulating atmosphere of the monastery Mehrerau, which provided the ideal environment for a limited number of invited participants to exchange ideas, without parallel sessions, and pursue deeper discussions (at the latest in the evening at "Gasthof Lamm"). When the conference series terminated in 2003, former participants were quite disappointed. Meeting again at several (larger) conferences in subsequent years, there were repeated expressions of "the lack of a Bregenz-type meeting in our field nowadays" and the question of a possible "revitalization", even without external funding. After some hesitation, but also driven by our own desire to reinstate the series, we consulted Bruno who not only approved wholeheartedly but also offered his full support. It all finally led to the symposium in July 2009. The atmosphere was really like in the "good old days" and the interesting and thought-provoking presentations culminated in the publication of these Proceedings. We are grateful to Carl Bender for establishing contact with IOP making it possible for us to publish these Proceedings in the Journal of Physics Conference Series. A majority of the participants contributed to these
Comparing Dualities and Gauge Symmetries
De Haro, Sebastian; Butterfield, Jeremy N
2016-01-01
We discuss some aspects of the relation between dualities and gauge symmetries. Both of these ideas are of course multi-faceted, and we confine ourselves to making two points. Both points are about dualities in string theory, and both have the 'flavour' that two dual theories are 'closer in content' than you might think. For both points, we adopt a simple conception of a duality as an 'isomorphism' between theories: more precisely, as appropriate bijections between the two theories' sets of states and sets of quantities. The first point (Section 3) is that this conception of duality meshes with two dual theories being 'gauge related' in the general philosophical sense of being physically equivalent. For a string duality, such as T-duality and gauge/gravity duality, this means taking such features as the radius of a compact dimension, and the dimensionality of spacetime, to be 'gauge'. The second point (Sections 4, 5 and 6) is much more specific. We give a result about gauge/gravity duality that shows its rela...
Bilateral symmetry across Aphrodite Terra
International Nuclear Information System (INIS)
There are three main highland areas on Venus: Beta Regio, Ishtar Terra and Aphrodite Terra. The latter is least known and the least mapped, yet existing analyses of Aphrodite Terra based on available Pioneer-Venus orbiter data suggest that it may be the site of extensive rifting. Some of the highest resolution (30 km) PV data (SAR) included most of the western half of Aphrodite Terra. Recent analysis of the SAR data together with Arecibo range-doppler topographic profiling (10 X 100 km horizontal and 10 m vertical resolution) across parts of Aphrodite, further characterized the nature of possible tectonic processes in the equatorial highlands. The existence of distinct topographic and radar morphologic linear discontinuities across the nearly east-west strike of Aphrodite Terra is indicated. Another prominent set of linear features is distinctly parallel to and orthogonal to the ground tracks of the PV spacecraft and are not included because of the possibility that they are artifacts. Study of the northwest trending cross-strike discontinuities (CSD's) and the nature of topographic and morphologic features along their strike suggest the presence of bilateral topographic and morphologic symmetry about the long axis of Aphrodite Terra
Symmetry properties of subdivision graphs
Daneshkhah, Ashraf; Praeger, Cheryl E
2010-01-01
The subdivision graph $S(\\Sigma)$ of a graph $\\Sigma$ is obtained from $\\Sigma$ by `adding a vertex' in the middle of every edge of $\\Si$. Various symmetry properties of $\\S(\\Sigma)$ are studied. We prove that, for a connected graph $\\Sigma$, $S(\\Sigma)$ is locally $s$-arc transitive if and only if $\\Sigma$ is $\\lceil\\frac{s+1}{2}\\rceil$-arc transitive. The diameter of $S(\\Sigma)$ is $2d+\\delta$, where $\\Sigma$ has diameter $d$ and $0\\leqslant \\delta\\leqslant 2$, and local $s$-distance transitivity of $\\S(\\Sigma)$ is defined for $1\\leqslant s\\leqslant 2d+\\delta$. In the general case where $s\\leqslant 2d-1$ we prove that $S(\\Sigma)$ is locally $s$-distance transitive if and only if $\\Sigma$ is $\\lceil\\frac{s+1}{2}\\rceil$-arc transitive. For the remaining values of $s$, namely $2d\\leqslant s\\leqslant 2d+\\delta$, we classify the graphs $\\Sigma$ for which $S(\\Sigma)$ is locally $s$-distance transitive in the cases, $s\\leqslant 5$ and $s\\geqslant 15+\\delta$. The cases $\\max\\{2d, 6\\}\\leqslant s\\leqslant \\min\\{2d+\\d...
Group symmetries and information propagation
International Nuclear Information System (INIS)
Spectroscopy concerns itself with the ways in which the Hamiltonian and other interesting operators defined in few-particle spaces are determined or determine properties of many-particle systems. But the action of the central limit theorem (CLT) filters the transmission of information between source and observed so whether propagating forward from a few-particle defining space, as is usual in theoretical studies, or projecting backward to it from measured things, each is only sensitive to averaged properties of the other. Our concern is with the propagation of spectroscopic information in the presence of good symmetries when filtering action of the CLT is effective. Specifically, we propose to address the question, What propagates and how. We begin with some examples, using both scalar and isospin geometries to illustrate simple propagation. Examples of matrix propagation are studied; contact with standard tensor algebra is established and an algorithm put forward for the expansion of any operator in terms of another set, complete or not; shell-model results for 20Ne using a realistic interaction and two trace-equivalent forms are presented; and some further challenges are mentioned
Structural symmetry in evolutionary games.
McAvoy, Alex; Hauert, Christoph
2015-10-01
In evolutionary game theory, an important measure of a mutant trait (strategy) is its ability to invade and take over an otherwise-monomorphic population. Typically, one quantifies the success of a mutant strategy via the probability that a randomly occurring mutant will fixate in the population. However, in a structured population, this fixation probability may depend on where the mutant arises. Moreover, the fixation probability is just one quantity by which one can measure the success of a mutant; fixation time, for instance, is another. We define a notion of homogeneity for evolutionary games that captures what it means for two single-mutant states, i.e. two configurations of a single mutant in an otherwise-monomorphic population, to be 'evolutionarily equivalent' in the sense that all measures of evolutionary success are the same for both configurations. Using asymmetric games, we argue that the term 'homogeneous' should apply to the evolutionary process as a whole rather than to just the population structure. For evolutionary matrix games in graph-structured populations, we give precise conditions under which the resulting process is homogeneous. Finally, we show that asymmetric matrix games can be reduced to symmetric games if the population structure possesses a sufficient degree of symmetry. PMID:26423436
Scalar Field Theories with Polynomial Shift Symmetries
Griffin, Tom; Horava, Petr; Yan, Ziqi
2014-01-01
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 (essen...
Borchers' commutation relations and modular symmetries
Kuckert, B
1995-01-01
Recently Borchers has shown that in a theory of local observables, certain unitary and antiunitary operators, which are obtained from an elementary construction suggested by Bisognano and Wichmann, commute with the translation operators like Lorentz boosts and \\pct-operators, respectively. We conclude from this that as soon as the operators considered implement {\\em any} symmetry, this symmetry can be fixed up to at most some translation. As a symmetry, we admit any unitary or antiunitary operator under whose adjoint action any algebra of local observables is mapped onto an algebra which can be localized somewhere in Minkowski space.
Symmetry in Image Registration and Deformation Modeling
DEFF Research Database (Denmark)
Sommer, Stefan; Jacobs, Henry O.
We survey the role of symmetry in diffeomorphic registration of landmarks, curves, surfaces, images and higher-order data. The infinite dimensional problem of finding correspondences between objects can for a range of concrete data types be reduced resulting in compact representations of shape and...... spatial structure. This reduction is possible because the available data is incomplete in encoding the full deformation model. Using reduction by symmetry, we describe the reduced models in a common theoretical framework that draws on links between the registration problem and geometric mechanics...... problem. We outline these constructions and further cases where reduction by symmetry promises new approaches to registration of complex data types....
Fractal Symmetries: Ungauging the Cubic Code
Williamson, Dominic J
2016-01-01
Gauging is a ubiquitous tool in many-body physics. It allows one to construct highly entangled topological phases of matter from relatively simple phases and to relate certain characteristics of the two. Here we develop a gauging procedure for general submanifold symmetries of Pauli Hamiltonians, including symmetries of fractal type. We show a relation between the pre- and post- gauging models and use this to construct short range entangled phases with fractal like symmetries, one of which is mapped to the cubic code by the gauging.
Inversion symmetry protected topological insulators and superconductors
Lee, Dung-Hai; Lu, Yuan-Ming
2015-03-01
Three dimensional topological insulator represents a class of novel quantum phases hosting robust gapless boundary excitations, which is protected by global symmetries such as time reversal, charge conservation and spin rotational symmetry. In this work we systematically study another class of topological phases of weakly interacting electrons protected by spatial inversion symmetry, which generally don't support stable gapless boundary states. We classify these inversion-symmetric topological insulators and superconductors in the framework of K-theory, and construct their lattice models. We also discuss quantized response functions of these inversion-protected topological phases, which serve as their experimental signatures.
Nuclear symmetry energy and neutron skin thickness
Warda, M; Viñas, X; Roca-Maza, X
2012-01-01
The relation between the slope of the nuclear symmetry energy at saturation density and the neutron skin thickness is investigated. Constraints on the slope of the symmetry energy are deduced from the neutron skin data obtained in experiments with antiprotonic atoms. Two types of neutron skin are distinguished: the "surface" and the "bulk". A combination of both types forms neutron skin in most of nuclei. A prescription to calculate neutron skin thickness and the slope of symmetry energy parameter $L$ from the parity violating asymmetry measured in the PREX experiment is proposed.
Symmetries of linearized gravity from adjoint operators
Aksteiner, Steffen
2016-01-01
Using a covariant formulation it is shown that the Teukolsky equation and the Teukolsky-Starobinsky identities for spin-1 and linearized gravity on a vacuum type D background are self-adjoint. This fact is used to construct symmetry operators for each of the four cases. We find both irreducible second order symmetry operators for spin-1, a known fourth order, and a new sixth order symmetry operator for linearized gravity. The results are connected to Hertz and Debye potentials and to the separability of the Teukolsky equation.
Implications of Local Chiral Symmetry Breaking
La, H S
2003-01-01
The spontaneous symmetry breaking of a local chiral symmetry to its diagonal vector symmetry naturally realizes a complete geometrical structure more general than that of Yang-Mills (YM) theory, rather similar to that of gravity. A good example is the Quantum Chromodynamics (QCD) with respect to the Chiral Color model. Also, a new anomaly-free particle content for a Chiral Color model is introduced: the Chiral Color can be realized without introducing whole new generations of quarks and leptons, but by simply enlarging each generation with new exotic fermions.
New hidden symmetries in 2-dimensional models
International Nuclear Information System (INIS)
In an attempt to derive the hidden symmetries for some integrable 2-dimensional models by considering the invariances of the corresponding linearization systems and the Riemann-Hilbert transformations, we arrive at a new ''sub''-algebra of the ordinary Kac-Moody algebra which represents the hidden symmetry for for example the sine-Gordon theory. A similar ''sub''-algebra is found for the Liouville model. These new algebras differ from the ordinary ones in having a different structure according to whether the grading is even or odd. We describe a new systematic way of finding such hidden symmetries from general linearization systems. (orig.)
Gauge origin of discrete flavor symmetries in heterotic orbifolds
Directory of Open Access Journals (Sweden)
Florian Beye
2014-09-01
Full Text Available We show that non-Abelian discrete symmetries in orbifold string models have a gauge origin. This can be understood when looking at the vicinity of a symmetry enhanced point in moduli space. At such an enhanced point, orbifold fixed points are characterized by an enhanced gauge symmetry. This gauge symmetry can be broken to a discrete subgroup by a nontrivial vacuum expectation value of the Kähler modulus T. Using this mechanism it is shown that the Δ(54 non-Abelian discrete symmetry group originates from a SU(3 gauge symmetry, whereas the D4 symmetry group is obtained from a SU(2 gauge symmetry.
Symmetry vs. Chaos in collective dynamics
International Nuclear Information System (INIS)
Models of nuclear collective dynamics are used to study the interplay of order (approximate dynamical symmetry) and chaos in general physical systems. We report on some recent results obtained within the interacting boson model and the geometric model. (author)
Symmetry and group theory throughout physics
Directory of Open Access Journals (Sweden)
Villain J.
2012-03-01
Full Text Available As noticed in 1884 by Pierre Curie [1], physical properties of matter are tightly related to the kind of symmetry of the medium. Group theory is a systematic tool, though not always easy to handle, to exploit symmetry properties, for instance to find the eigenvectors and eigenvalues of an operator. Certain properties (optical activity, piezoelectricity are forbidden in molecules or crystals of high symmetry. A few theorems (Noether, Goldstone establish general relations between physical properties and symmetry. Applications of group theory to condensed matter physics, elementary particle physics, quantum mechanics, electromagnetism are reviewed. Group theory is not only a tool, but also a beautiful construction which casts insight into natural phenomena.
Permutation Symmetry Determines the Discrete Wigner Function
Zhu, Huangjun
2016-01-01
The Wigner function provides a useful quasiprobability representation of quantum mechanics, with applications in various branches of physics. Many nice properties of the Wigner function are intimately connected with the high symmetry of the underlying operator basis composed of phase point operators: any pair of phase point operators can be transformed to any other pair by a unitary symmetry transformation. We prove that, in the discrete scenario, this permutation symmetry is equivalent to the symmetry group being a unitary 2 design. Such a highly symmetric representation can only appear in odd prime power dimensions besides dimensions 2 and 8. It suffices to single out a unique discrete Wigner function among all possible quasiprobability representations. In the course of our study, we show that this discrete Wigner function is uniquely determined by Clifford covariance, while no Wigner function is Clifford covariant in any even prime power dimension.
Enhanced breaking of heavy quark spin symmetry
Guo, Feng-Kun; Shen, Cheng-Ping
2014-01-01
Heavy quark spin symmetry is useful to make predictions on ratios of decay or production rates of systems involving heavy quarks. The breaking of spin symmetry is generally of the order of $O({\\Lambda_{\\rm QCD}/m_Q})$, with $\\Lambda_{\\rm QCD}$ the scale of QCD and $m_Q$ the heavy quark mass. In this paper, we propose a new mechanism to enhance the spin symmetry breaking. Taking the decays of the $\\Upsilon(10860)$ into the $\\chi_{bJ}\\omega\\, (J=0,1,2)$ as an example, we show that a small $S$- and $D$-wave mixing can induce a significant breaking of the spin symmetry relations for the ratios of the branching fractions of these decays, owing to an enhancement of the decays of the $D$-wave component due to nearby coupled channels.
Compact stars and the symmetry energy
Providência, Constana; Cavagnoli, Rafael; Menezes, Debora P.; Panda, Prafulla K.; Rabhi, Aziz
2013-02-01
The effect of the symmetry energy on some properties of compact stars which contain strange degrees of freedom is discussed. Both the onset of hyperons or kaon condensation will be considered. The hyperon-meson couplings are chosen according to experimental values of the hyperon nuclear matter potentials and possible uncertainties are considered. It is shown that a softer symmetry energy affects the onset of strangeness, namely neutral (negatively charged) strange particles set on at larger (smaller) densities, and gives rise to a smaller strangeness fraction as a function of density. A softer symmetry energy will possibily give rise to maximum mass configurations with larger masses. Hyperon-meson couplings have a strong effect on the mass of the star. It is shown that, for stars with masses above 1 Msolar, the radius of the star varies linearly with the symmetry energy slope L.
Chiral symmetry breaking in brane models
International Nuclear Information System (INIS)
We discuss the chiral symmetry breaking in general intersecting Dq/Dp brane models consisting of Nc Dq-branes and a single Dp-brane with an s-dimensional intersection. There exists a QCD-like theory localized at the intersection and the Dq/Dp model gives a holographic description of it. The rotational symmetry of directions transverse to both of the Dq and Dp-branes can be identified with a chiral symmetry, which is non-Abelian for certain cases. The asymptotic distance between the Dq-branes and the Dp-brane corresponds to a quark mass. By studying the probe Dp-brane dynamics in a Dq-brane background in the near horizon and large Nc limit we find that the chiral symmetry is spontaneously broken and there appear (pseudo-)Nambu-Goldstone bosons. We also discuss the models at finite temperature
Magnetic rotation and chiral symmetry breaking
Indian Academy of Sciences (India)
Ashok Kumar Jain; Amita
2001-08-01
The deformed mean ﬁeld of nuclei exhibits various geometrical and dynamical symmetries which manifest themselves as various types of rotational and decay patterns. Most of the symmetry operations considered so far have been deﬁned for a situation wherein the angular momentum coincides with one of the principal axes and the principal axis cranking may be invoked. New possibilities arise with the observation of rotational features in weakly deformed nuclei and now interpreted as magnetic rotational bands. More than 120 MR bands have now been identiﬁed by ﬁltering the existing data. We present a brief overview of these bands. The total angular momentum vector in such bands is tilted away from the principal axes. Such a situation gives rise to several new possibilities including breaking of chiral symmetry as discussed recently by Frauendorf. We present the outcome of such symmetries and their possible experimental veriﬁcation. Some possible examples of chiral bands are presented.
Nobel Prize for work on broken symmetries
2008-01-01
The 2008 Nobel Prize for Physics goes to three physicists who have worked on broken symmetries in particle physics. The announcement of the 2008 Nobel Prize for physics was transmitted to the Globe of Science and Innovation via webcast on the occasion of the preview of the Nobel Accelerator exhibition.On 7 October it was announced that the Royal Swedish Academy of Sciences had awarded the 2008 Nobel Prize for physics to three particle physicists for their fundamental work on the mechanisms of broken symmetries. Half the prize was awarded to Yoichiro Nambu of Fermilab for "the discovery of the mechanism of spontaneous broken symmetry in subatomic physics". The other half is shared by Makato Kobayashi of Japan’s KEK Institute and Toshihide Maskawa of the Yukawa Institute at the University of Kyoto "for the discovery of the origin of the broken symmetry which predicts the existence of at least three families of quarks in Nature". At th...
Spatial symmetries of the local densities
Rohozinski, S. G.; Dobaczewski, J.; Nazarewicz, W.
2010-01-01
Spatial symmetries of the densities appearing in the nuclear Density Functional Theory are discussed. General forms of the local densities are derived by using methods of construction of isotropic tensor fields. The spherical and axial cases are considered.
Chiral Symmetry Restoration from a Boundary
Tiburzi, B C
2013-01-01
The boundary of a manifold can alter the phase of a theory in the bulk. We explore the possibility of a boundary-induced phase transition for the chiral symmetry of QCD. In particular, we investigate the consequences of imposing homogeneous Dirichlet boundary conditions on the quark fields. Such boundary conditions are employed on occasion in lattice gauge theory computations, for example, when including external electromagnetic fields, or when computing quark propagators with a reduced temporal extent. Homogeneous Dirichlet boundary conditions force the chiral condensate to vanish at the boundary, and thereby obstruct the spontaneous breaking of chiral symmetry in the bulk. As the restoration of chiral symmetry due to a boundary is a non-perturbative phenomenon, we utilize the sigma model to exemplify the issues. Using this model, we find that chiral symmetry is completely restored if the length of the compact direction is less than 2.0 fm. For lengths greater than about 4 fm, an approximately uniform chiral...
$\\Delta(27)$ family symmetry and neutrino mixing
Varzielas, Ivo de Medeiros
2015-01-01
The observed neutrino mixing, having a near maximal atmospheric neutrino mixing angle and a large solar mixing angle, is close to tri-bi-maximal. This structure may be related to the existence of a discrete non-Abelian family symmetry. In this paper the family symmetry is the non-Abelian discrete group $\\Delta(27)$, a subgroup of $SU(3)$ with triplet and anti-triplet representations. Different frameworks are constructed in which the mixing follows from combining fermion mass terms with the vacuum structure enforced by the discrete symmetry. Mass terms for the fermions originate from familon triplets, anti-triplets or both. Vacuum alignment for the family symmetry breaking familons follows from simple invariants.
$R$ parity violation from discrete $R$ symmetries
Chen, Mu-Chun; Takhistov, Volodymyr
2015-01-01
We consider supersymmetric extensions of the standard model in which the usual $R$ or matter parity gets replaced by another $R$ or non-$R$ discrete symmetry that explains the observed longevity of the nucleon and solves the $\\mu$ problem of MSSM. In order to identify suitable symmetries, we develop a novel method of deriving the maximal $\\mathbb{Z}_{N}^{(R)}$ symmetry that satisfies a given set of constraints. We identify $R$ parity violating (RPV) and conserving models that are consistent with precision gauge unification and also comment on their compatibility with a unified gauge symmetry such as the Pati-Salam group. Finally, we provide a counter-example to the statement found in the recent literature that the lepton number violating RPV scenarios must have $\\mu$ term and the bilinear $\\kappa \\, L \\, H_u$ operator of comparable magnitude.
Personal recollections on chiral symmetry breaking
Kobayashi, Makoto
2016-07-01
The author's work on the mass of pseudoscalar mesons is briefly reviewed. The emergence of the study of CP violation in the renormalizable gauge theory from consideration of chiral symmetry in the quark model is discussed.
On topological symmetries and the Goldstone theorem
International Nuclear Information System (INIS)
We show that one cannot achieve the symmetry breaking condition limR→∞R,Ω)> ≠ 0 when QR is the (finite volume) integral of a topological charge density and Ω has a compact support. This implies that topological symmetries are never broken spontaneously. If one attempts to use an operator Ω' whose support extends to spatial infinity as an order parameter the resulting symmetry breaking condition can be formally satisfied, but the Goldstone theorem does not apply because, in general, the topological charge is no longer conserved. This (wrong) symmetry breaking condition need not contain any dynamical information and merely reflects the effect of Ω' on the boundary conditions at spatial infinity. (author). 5 refs
On a symmetry relating gravity with antigravity
Quiros, Israel
2014-01-01
I investigate the impact of a "would be" fundamental symmetry of the laws of nature under the interchange of gravity and antigravity, on the understanding of negative energies in general relativity. For this purpose a toy model that is based on Einstein-Hilbert gravity with two minimally coupled self-interacting scalar fields is explored, where the second (exotic) scalar field with negative energy density may be regarded, alternatively, as an antigravitating field with positive energy. Spontaneous breakdown of reflection symmetry is then considered in order to discuss the implications the proposed "would be" fundamental symmetry might have for the vanishing of the cosmological constant. A possible connection of the gravity-antigravity symmetry with the so called quintom field is also explored.
Symmetries, Groups, Groupoids and Systems of Systems
Alonso, E.; Karcanias, N.; Hessami, A. G.
2013-01-01
In this paper we propose an algebraic model of systems based on the concept of symmetry that can be instrumental in representing Systems of Systems two main characteristics, namely complexity and (hierarchical) emergence.
Introduction "Workplace (a)symmetries: multimodal perspectives"
DEFF Research Database (Denmark)
Asmuss, Birte
Following the seminal work on talk at work (Drew and Heritage, 1992) and later studies on interaction in institutional interaction (Arminen, 2005; Asmuß & Svennevig, 2009; Svennevig 2012a), the panel seeks to pursue the role of interactional micro-practices for the emergence of workplace symmetries...... and asymmetries. Workplaces are settings where different kinds of (a)symmetries are constructed through interaction ((Svennevig, 2012b, Asmuß, 2008). In comparison to interactions between professionals and laypeople, identities in workplace interactions where colleagues interact with each other may be...... more complex due to multiple roles and team alliances (Pomerantz & Denvir, 2007; Djordjilovic, 2012). Thus, participants of workplace interaction have to negotiate their position in a dynamically fluctuating network of symmetries and asymmetries. The emergence of symmetries and asymmetries in talk has...
Opinion Crystallography: Polarizations, Symmetries, Bonds, and Bands
Tuncay, Caglar
2006-01-01
May randomness (real numbers, opinions) evolve into order (regularity) with time? We study some polarization and symmetry properties, which emerge in time evolution of opinions (real numbers) within entries of two and three-dimensional lattices, which had initial randomness.
Discrete symmetries in space and time
International Nuclear Information System (INIS)
In the report the discrete symmetries C (charge conjugation), P (parity or space inversion) and T (time reversal). After a short introduction to the symmetries in Particle Physics the violations in the P, C, CP and T processes controlled by one of the four basic forces, the week force are mentioned. A CP violation may play an important part in enlightening the origin of the matter - antimatter asymmetry in the universe. The so-called ''strange'' particles, the K mesons, have given valuable information about the discrete symmetries for several decades. Recently the ''beautiful'' particles, the B mesons, arrived and through them the understanding of the fundamental (a)symmetries will be deepened in the years to come
Adaptive estimation of qubits by symmetry measurements
Happ, Christof J.; Freyberger, Matthias
2008-01-01
We analyze quantum state estimation for finite samples based on symmetry information. The used measurement concept compares an unknown qubit to a reference state. We describe explicitly an adaptive strategy, that enhances the estimation fidelity of these measurements.
Conformal correlators of mixed-symmetry tensors
Costa, Miguel S
2015-01-01
We generalize the embedding formalism for conformal field theories to the case of general operators with mixed symmetry. The index-free notation encoding symmetric tensors as polynomials in an auxiliary polarization vector is extended to mixed-symmetry tensors by introducing a new commuting or anticommuting polarization vector for each row or column in the Young diagram that describes the index symmetries of the tensor. We determine the tensor structures that are allowed in n-point conformal correlation functions and give an algorithm for counting them in terms of tensor product coefficients. We show, with an example, how the new formalism can be used to compute conformal blocks of arbitrary external fields for the exchange of any conformal primary and its descendants. The matching between the number of tensor structures in conformal field theory correlators of operators in d dimensions and massive scattering amplitudes in d+1 dimensions is also seen to carry over to mixed-symmetry tensors.
R parity violation from discrete R symmetries
Directory of Open Access Journals (Sweden)
Mu-Chun Chen
2015-02-01
Full Text Available We consider supersymmetric extensions of the standard model in which the usual R or matter parity gets replaced by another R or non-R discrete symmetry that explains the observed longevity of the nucleon and solves the μ problem of MSSM. In order to identify suitable symmetries, we develop a novel method of deriving the maximal ZN(R symmetry that satisfies a given set of constraints. We identify R parity violating (RPV and conserving models that are consistent with precision gauge unification and also comment on their compatibility with a unified gauge symmetry such as the Pati–Salam group. Finally, we provide a counter-example to the statement found in the recent literature that the lepton number violating RPV scenarios must have μ term and the bilinear κLHu operator of comparable magnitude.
New symmetry in the Rabi model
International Nuclear Information System (INIS)
It is recognized that, apart from the total energy conservation, there is a nonlocal Z2 and a somewhat hidden symmetry in this model. Conditions for the existence of this observable, its form and its explicit construction are presented. (paper)
Spontaneous chiral symmetry breaking in metamaterials
Liu, Mingkai; Powell, David A.; Shadrivov, Ilya V.; Lapine, Mikhail; Kivshar, Yuri S.
2014-07-01
Spontaneous chiral symmetry breaking underpins a variety of areas such as subatomic physics and biochemistry, and leads to an impressive range of fundamental phenomena. Here we show that this prominent effect is now available in artificial electromagnetic systems, enabled by the advent of magnetoelastic metamaterials where a mechanical degree of freedom leads to a rich variety of strong nonlinear effects such as bistability and self-oscillations. We report spontaneous symmetry breaking in torsional chiral magnetoelastic structures where two or more meta-molecules with opposite handedness are electromagnetically coupled, modifying the system stability. Importantly, we show that chiral symmetry breaking can be found in the stationary response of the system, and the effect is successfully demonstrated in a microwave pump-probe experiment. Such symmetry breaking can lead to a giant nonlinear polarization change, energy localization and mode splitting, which provides a new possibility for creating an artificial phase transition in metamaterials, analogous to that in ferrimagnetic domains.
Bosonic symmetries of the Dirac equation
International Nuclear Information System (INIS)
We have found on the basis of the symmetry analysis of the standard Dirac equation with nonzero mass the new physically meaningful features of this equation. The new bosonic symmetries of the Dirac equation in both the Foldy-Wouthuysen and the Pauli-Dirac representations are found, among which (together with the 32-dimensional pure matrix algebra of invariance) the new spin s=(1,0) multiplet Poincare symmetry is proved. In order to carry out the corresponding proofs a 64-dimensional extended real Clifford-Dirac algebra is put into consideration. -- Highlights: → The 64-dimensional extended real Clifford-Dirac algebra is put into consideration. → Maximal pure matrix algebra of invariance of the Foldy-Wouthuysen equation is found. → The spin (1,0) Lorentz and Poincare symmetries of the Dirac equation are proved.
Bosonic symmetries of the Dirac equation
Energy Technology Data Exchange (ETDEWEB)
Simulik, V.M., E-mail: vsimulik@gmail.com [Institute of Electron Physics, National Academy of Sciences of Ukraine, 21 Universitetska Str., 88000 Uzhgorod (Ukraine); Krivsky, I.Yu. [Institute of Electron Physics, National Academy of Sciences of Ukraine, 21 Universitetska Str., 88000 Uzhgorod (Ukraine)
2011-06-20
We have found on the basis of the symmetry analysis of the standard Dirac equation with nonzero mass the new physically meaningful features of this equation. The new bosonic symmetries of the Dirac equation in both the Foldy-Wouthuysen and the Pauli-Dirac representations are found, among which (together with the 32-dimensional pure matrix algebra of invariance) the new spin s=(1,0) multiplet Poincare symmetry is proved. In order to carry out the corresponding proofs a 64-dimensional extended real Clifford-Dirac algebra is put into consideration. -- Highlights: → The 64-dimensional extended real Clifford-Dirac algebra is put into consideration. → Maximal pure matrix algebra of invariance of the Foldy-Wouthuysen equation is found. → The spin (1,0) Lorentz and Poincare symmetries of the Dirac equation are proved.
Symmetry energy from QCD sum rules
International Nuclear Information System (INIS)
We review the recent attempts to calculate the nuclear symmetry energy from QCD sum rules. Calculating the difference between the proton and neutron correlation function in an isospin asymmetric nuclear matter within the QCD sum rule approach, the potential part of the nuclear symmetry energy can be expressed in terms of local operators. We find that the scalar (vector) self-energy part gives negative (positive) contribution to the nuclear symmetry energy, consistent with the results from relativistic mean-field theories. Moreover, the magnitudes are consistent with phenomenological estimates. In terms of the operators, we find that an important contribution to self-energies contributing to the symmetry energy comes from the twist-4 matrix elements, whose leading density dependence can be extracted from deep inelastic scattering experiments. Our result also extends an early success of the QCD sum rule method in understanding the symmetric nuclear matter in terms of QCD variables to the asymmetric nuclear matter case. (orig.)
Student understanding of Symmetry and Gauss' law
Singh, Chandralekha
2016-01-01
Helping students learn why Gauss' law can or cannot be easily applied to determine the strength of the electric field at various points for a particular charge distribution, and then helping them learn to determine the shape of the Gaussian surfaces if sufficient symmetry exists can develop their reasoning and problem solving skills. We investigate the difficulties that students in calculus-based introductory physics courses have with the concepts of symmetry, electric field and electric flux that are pivotal to Gauss' law of electricity. Determination of the electric field using Gauss' law requires discerning the symmetry of a particular charge distribution and being able to predict the direction of the electric field everywhere if a high symmetry exists. It requires a good grasp of how to add the electric field vectors using the principle of superposition, and the concepts of area vector and electric flux. We administered free response and multiple-choice questions and conducted interviews with individual s...
Symmetries in Non-Linear Mechanics
Aldaya, Victor; López-Ruiz, Francisco F; Cossío, Francisco
2014-01-01
In this paper we exploit the use of symmetries of a physical system so as to characterize the corresponding solution manifold by means of Noether invariants. This constitutes a necessary preliminary step towards the correct quantisation in non-linear cases, where the success of Canonical Quantisation is not guaranteed in general. To achieve this task "point symmetries" of the Lagrangian are generally not enough, and the notion of contact transformations is in order. The use of the Poincar\\'e-Cartan form permits finding both the symplectic structure on the solution manifold, through the Hamilton-Jacobi transformation, and the required symmetries, realized as Hamiltonian vector fields, associated with functions on the solution manifold (thus constituting an inverse of the Noether Theorem), lifted back to the evolution space through the inverse of this Hamilton-Jacobi mapping. In this framework, solutions and symmetries are somehow identified and this correspondence is also kept at a perturbative level. We prese...
Symmetry reduction of quasi-free states
International Nuclear Information System (INIS)
Given a group-invariant quasi-free state on the algebra of canonical commutation relations (CCR), we show how group averaging techniques can be used to obtain a symmetry-reduced CCR algebra and reduced quasi-free state. When the group is compact, this method of symmetry reduction leads to standard results which can be obtained using other methods. When the group is noncompact, the group averaging prescription relies on technically favorable conditions which we delineate. As an example, we consider symmetry reduction of the usual vacuum state for a Klein-Gordon field on Minkowski spacetime by a noncompact subgroup of the Poincare group consisting of a 1-parameter family of boosts, a 1-parameter family of spatial translations and a set of discrete translations. We show that the symmetry-reduced CCR algebra and vacuum state correspond to that used by each of Berger, Husain, and Pierri for the polarized Gowdy T3 quantum gravity model.
Hidden Superconformal Symmetry of the Cosmological Evolution
Kallosh, Renata
2013-01-01
In the superconformal formulation of supergravity, the standard supergravity action appears as a result of spontaneous symmetry breaking when the conformal compensator scalar field, the conformon, acquires a nonzero value, giving rise to the Planck mass. After that, many symmetries of the original theory become well hidden, and therefore they are often ignored. However, recent developments demonstrated that superconformal invariance is more than just a tool: it plays an important role in generalizing previously existing formulations of supergravity and developing new classes of inflationary models. In this paper we describe hidden superconformal symmetry of the cosmological evolution. In this formulation, inflation can be equivalently described as the conformon instability, and creation of the universe `from nothing' can be interpreted as spontaneous symmetry breaking due to emergence of a classical conformon field. We develop a general formalism that allows to describe the cosmological evolution simultaneous...
Dynamical symmetry approach to periodic Hamiltonians
International Nuclear Information System (INIS)
We show that dynamical symmetry methods can be applied to Hamiltonians with periodic potentials. We construct dynamical symmetry Hamiltonians for the Scarf potential and its extensions using representations of su(1,1) and so(2,2). Energy bands and gaps are readily understood in terms of representation theory. We compute the transfer matrices and dispersion relations for these systems, and find that the complementary series plays a central role as well as nonunitary representations. (c) 2000 American Institute of Physics
Testing Chiral Symmetry Breaking at DAPHNE
M. R. Pennington
1996-01-01
The spontaneous breakdown of the chiral symmetry of the QCD Lagrangian ensures that $\\pi\\pi$ interactions are weak at low energies. How weak depends on the nature of explicit symmetry breaking. Measurements of $K_{e4}$ decays at DA$\\Phi$NE will provide a unique insight into this mechanism and test whether the $q{\\overline q}$--condensate is large or small.
On gradient Ricci solitons with Symmetry
Petersen, Peter; Wylie, William
2007-01-01
We study gradient Ricci solitons with maximal symmetry. First we show that there are no non-trivial homogeneous gradient Ricci solitons. Thus the most symmetry one can expect is an isometric cohomogeneity one group action. Many examples of cohomogeneity one gradient solitons have been constructed. However, we apply the main result in our paper "Rigidity of gradient Ricci solitons" to show that there are no noncompact cohomogeneity one shrinking gradient solitons with nonnegative curvature.
Symmetry energy in cold dense matter
Jeong, Kie Sang; Lee, Su Houng
2015-01-01
We calculate the symmetry energy in cold dense matter both in the normal quark phase and in the 2-color superconductor (2SC) phase. For the normal phase, the thermodynamic potential is calculated by using hard dense loop (HDL) resummation to leading order, where the dominant contribution comes from the longitudinal gluon rest mass. The effect of gluonic interaction to the symmetry energy, obtained from the thermodynamic potential, was found to be small. In the 2SC phase, the non-perturbative ...
Continuous point symmetries in Group Field Theories
Kegeles, Alexander
2016-01-01
We discuss the notion of symmetries in non-local field theories characterized by integro-differential equation of motion, from a geometric perspective. We then focus on Group Field Theory (GFT) models of quantum gravity. We provide a general analysis of their continuous point symmetry transformations, including the generalized conservation laws following from them, and apply it to several GFT models of interest to current research.
Indian Academy of Sciences (India)
S D Maharaj; D B Lorthan
2011-09-01
We investigate the role of symmetries for charged perfect fluids by assuming that spacetime admits a conformal Killing vector. The existence of a conformal symmetry places restrictions on the model. It is possible to ﬁnd a general relationship for the Lie derivative of the electromagnetic ﬁeld along the integral curves of the conformal vector. The electromagnetic ﬁeld is mapped conformally under particular conditions. The Maxwell equations place restrictions on the form of the proper charge density.
Symmetry characterization of electrons and lattice excitations
Schober H.
2012-01-01
Symmetry concerns all aspects of a physical system from the electronic orbitals to structural and magnetic excitations. In this article we will try to elaborate the fundamental connection between symmetry and excitations. As excitations are manyfold in physical systems it is impossible to treat them exhaustively. We thus concentrate on the two topics of Bloch electrons and phonons. These two examples are complementary in the sense that Bloch electrons describe single particles in an external ...
Reverse-symmetry waveguides: Theory and fabrication
DEFF Research Database (Denmark)
Horvath, R.; Lindvold, Lars René; Larsen, N.B.
2002-01-01
We present an extensive theoretical analysis of reverse-symmetry waveguides with special focus on their potential application as sensor components in aqueous media and demonstrate a novel method for fabrication of such waveguides. The principle of reverse symmetry is based on making the refractive...... has the advantage of deeper penetration of the evanescent electromagnetic field into the cover medium, theoretically permitting higher sensitivity to analytes compared to traditional waveguide designs. We present calculated sensitivities and probing depths of conventional and reverse...
Nanostructure symmetry: Relevance for physics and computing
Energy Technology Data Exchange (ETDEWEB)
Dupertuis, Marc-André; Oberli, D. Y. [Laboratory for Physics of Nanostructure, EPF Lausanne (Switzerland); Karlsson, K. F. [Department of Physics, Chemistry, and Biology (IFM), Linköping University (Sweden); Dalessi, S. [Computational Biology Group, Department of Medical Genetics, University of Lausanne (Switzerland); Gallinet, B. [Nanophotonics and Metrology Laboratory, EPF Lausanne (Switzerland); Svendsen, G. [Dept. of Electronics and Telecom., Norwegian University of Science and Technology, Trondheim (Norway)
2014-03-31
We review the research done in recent years in our group on the effects of nanostructure symmetry, and outline its relevance both for nanostructure physics and for computations of their electronic and optical properties. The exemples of C3v and C2v quantum dots are used. A number of surprises and non-trivial aspects are outlined, and a few symmetry-based tools for computing and analysis are shortly presented.
Inextendibility of expanding cosmological models with symmetry
Energy Technology Data Exchange (ETDEWEB)
Dafermos, Mihalis [University of Cambridge, Department of Pure Mathematics and Mathematical Statistics, Wilberforce Road, Cambridge CB3 0WB (United Kingdom); Rendall, Alan D [Max Planck Institute for Gravitational Physics, Albert Einstein Institute, Am Muehlenberg 1, D-14476 Golm (Germany)
2005-12-07
A new criterion for inextendibility of expanding cosmological models with symmetry is presented. It is applied to derive a number of new results and to simplify the proofs of existing ones. In particular, it shows that the solutions of the Einstein-Vlasov system with T{sup 2} symmetry, including the vacuum solutions, are inextendible in the future. The technique introduced adds a qualitatively new element to the available tool-kit for studying strong cosmic censorship. (letter to the editor)
Symmetry Properties of Optimal Relative Orbit Trajectories
Mauro Pontani
2015-01-01
The determination of minimum-fuel or minimum-time relative orbit trajectories represents a classical topic in astrodynamics. This work illustrates some symmetry properties that hold for optimal relative paths and can considerably simplify their determination. The existence of symmetry properties is demonstrated in the presence of certain boundary conditions for the problems of interest, described by the linear Euler-Hill-Clohessy-Wiltshire equations of relative motion. With regard to minimum-...
IBM symmetries in realistic shell model states
International Nuclear Information System (INIS)
An approximate dynamical symmetry referring to IBM-type bosons is shown to be latent in the shell model eigenfunctions for 54Cr and 56Fe. No symmetry is assumed in the approach, which invokes only a realistic shell model interaction and an interpretation of the bosons as nucleon pairs. Particular emphasis is placed on the levels involved in M1 excitation. 25 refs., 4 tabs., 1 fig
Neutrino masses, magnetic moments, and horizontal symmetries
International Nuclear Information System (INIS)
We investigate the general structure of the neutrino mass and magnetic matrices in the presence of an unbroken horizontal symmetry. In particular, we study the compatibility of masslessness induced by such a symmetry and a non-zero magnetic moment. We show that in this case at least two of the charged leptons must have equal masses. Furthermore, we give a general definition of Dirac neutrinos and demonstrate that they are not necessarily associated with a lepton number. (Author) 15 refs
Quark matter symmetry energy and quark stars
Chu, Peng-Cheng; Chen, Lie-Wen
2012-01-01
We extend the confined-density-dependent-mass (CDDM) model to include isospin dependence of the equivalent quark mass. Within the confined-isospin-density-dependent-mass (CIDDM) model, we study the quark matter symmetry energy, the stability of strange quark matter, and the properties of quark stars. We find that including isospin dependence of the equivalent quark mass can significantly influence the quark matter symmetry energy as well as the properties of strange quark matter and quark sta...
Mirror symmetry breaking at the molecular level.
Avetisov, V; Goldanskii, V.
1996-01-01
Reasoning from two basic principles of molecular physics, P invariance of electromagnetic interaction and the second law of thermodynamics, one would conclude that mirror symmetry retained in the world of chiral molecules. This inference is fully consistent with what is observed in inorganic nature. However, in the bioorganic world, the reverse is true. Mirror symmetry there is definitely broken. Is it possible to account for this phenomenon without going beyond conventional concepts of the k...
Black Hole Thermodynamics and Lorentz Symmetry
Jacobson, Ted
2008-01-01
Recent developments point to a breakdown in the generalized second law of thermodynamics for theories with Lorentz symmetry violation. It appears possible to construct a perpetual motion machine of the second kind in such theories, using a black hole to catalyze the conversion of heat to work. Here we describe the arguments leading to that conclusion. We suggest the implication that Lorentz symmetry should be viewed as an emergent property of the macroscopic world, required by the second law of black hole thermodynamics.
Teaching symmetry in the introductory physics curriculum
Energy Technology Data Exchange (ETDEWEB)
Hill, Christopher T.; Lederman, Leon M.
2000-01-01
Modern physics is largely defined by fundamental symmetry principles and Noether's Theorem. Yet these are not taught, or rarely mentioned, to beginning students, thus missing an opportunity to reveal that the subject of physics is as lively and contemporary as molecular biology, and as beautiful as the arts. We prescribe a symmetry module to insert into the curriculum, of a week's length.
On some Symmetry Axioms in Relativity Theories
Székely, Gergely
2016-01-01
In this paper we review two symmetry axioms of special relativity and their connections to each other together with their role in some famous predictions of relativity theory, such as time dilation, length contraction, and the twin paradox. We also discuss briefly counterparts of these symmetry axioms in general relativity and formulate a conjecture, namely that without them the axioms of general relativity would capture general relativistic spacetimes only up to conformal equivalence.
Theory of broken gauge symmetry of families
International Nuclear Information System (INIS)
A theoretical scheme is considered, based on the gauge spontaneously-broken SU(3)H symmetry of families. The generation of quark and lepton masses is induced by their mixing with hypothetical superheavy fermions, providing a relationship of the observed mass hierarchy and mixing of quarks and leptons with the structure of horizontal symmetry breaking. The model predicts the existance of invisible axion, being simultaneously familon and Majoron, as well as the existence of neutrino Majorana mass hierarchy
The BRST symmetry and the fictitious parameters
Nogueira, A A
2016-01-01
Our goal in this work is to present the variational method of fictitious parameters and its connection with the BRST symmetry. Firstly we implement the method in QED at zero temperature and then we extend the analysis to GQED at finite temperature. As we will see the core of the study is the general statement in gauge theories at finite temperature, assigned by Tyutin work, that the physics does not depend on the gauge choices, covariant or not, due to BRST symmetry.
Nuclear Collective Models and Partial Symmetries
International Nuclear Information System (INIS)
It is shown that a mathematical modelling of the collective vibrations in the presence of the tetrahedral symmetry, in contrast to the previous simplistic predictions, may lead to large quadrupole moments Q0 in the tetrahedral symmetry nuclear bands. Their tetrahedral character originates from the fact that the vibrations take place around a tetrahedral minimum, however, a large amplitude vibrations collect large contributions to Q0. (authors)
On hidden symmetry in General Relativity
International Nuclear Information System (INIS)
It is shown that one of the fundamental principles of Nature, that the equations expressing basic laws should be invariant under the widest possible group of transformation fulfills in General Relativity not only from the point of view of space-time symmetry but also in the framework of gauge symmetry. The gauge-invariant equations are derived, which provide the solution of the Einstein problem on the full geometrization of General Relativity. 6 refs
Clusters and the quasi-dynamical symmetry
International Nuclear Information System (INIS)
The possible role of the quasi-dynamical symmetry in nuclear clusterization is discussed. Two particular examples are considered: i) the phases and phase-transitions of some algebraic cluster models, and ii) the clusterization in heavy nuclei. The interrelation of exotic (superdeformed, hyperdeformed) nuclear shapes and cluster-configurations are also investigated both for light, and for heavy nuclei, based on the dynamical and quasi-dynamical SU(3) symmetries, respectively
Center vortices, confinement and chiral symmetry breaking
International Nuclear Information System (INIS)
The center vortex model, proposed as an explanation of confinement in non-abelian gauge theories is introduced. Some checks of the confinement properties of center vortices in SU(2) lattice gauge theory with improved Luescher-Weisz gauge action are presented. Phenomena related to chiral symmetry, such as topological charge and spontaneous chiral symmetry breaking (SCSB) are studied within the vortex model. In particular the influence of center vortices on the low-lying spectrum of the Dirac operator is analyzed. (author)
Canonical equations of Hamilton with beautiful symmetry
Liang, Guo; Guo, Qi
2012-01-01
The Hamiltonian formulation plays the essential role in constructing the framework of modern physics. In this paper, a new form of canonical equations of Hamilton with the complete symmetry is obtained, which are valid not only for the first-order differential system, but also for the second-order differential system. The conventional form of the canonical equations without the symmetry [Goldstein et al., Classical Mechanics, 3rd ed, Addison-Wesley, 2001] are only for the second-order differe...
Automatic Gait Recognition by Symmetry Analysis
Hayfron-Acquah, James B.; Nixon, Mark S.; Carter, John N.
2001-01-01
We describe a new method for automatic gait recognition based on analysing the symmetry of human motion, by using the Generalised Symmetry Operator. This operator, rather than relying on the borders of a shape or on general appearance, locates features by their symmetrical properties. This approach is reinforced by the psychologists' view that gait is a symmetrical pattern of motion and by other works. We applied our new method to two different databases and derived gait signatures for silhou...
Nanostructure symmetry: Relevance for physics and computing
International Nuclear Information System (INIS)
We review the research done in recent years in our group on the effects of nanostructure symmetry, and outline its relevance both for nanostructure physics and for computations of their electronic and optical properties. The exemples of C3v and C2v quantum dots are used. A number of surprises and non-trivial aspects are outlined, and a few symmetry-based tools for computing and analysis are shortly presented
Chimera Death: Symmetry Breaking in Dynamical Networks
Zakharova, Anna; Kapeller, Marie; Schöll, Eckehard
2014-01-01
For a network of generic oscillators with nonlocal topology and symmetry-breaking coupling we establish novel partially coherent inhomogeneous spatial patterns, which combine the features of chimera states (coexisting incongruous coherent and incoherent domains) and oscillation death (oscillation suppression), which we call chimera death. We show that due to the interplay of nonlocality and breaking of rotational symmetry by the coupling two distinct scenarios from oscillatory behavior to a s...
Model of flavor with quaternion symmetry
Aranda, Alfredo; Bonilla, Cesar; Ramos, Raymundo; Rojas, Alma D.
2011-01-01
We present a renormalizable fermion mass model based on the symmetry $Q_4$ that accommodates all fermion masses and mixing angles in both the quark and lepton sectors. It requires the presence of only four SU(2) doublet scalar fields transforming non trivially under the flavor symmetry and the assumption of an alignment between first and second generation Yukawa couplings. No right-handed neutrinos are present in the model and neutrino masses are generated radiatively through the introduction...
Black Hole Thermodynamics and Lorentz Symmetry
Jacobson, Ted; Wall, Aron C.
2008-01-01
Recent developments point to a breakdown in the generalized second law of thermodynamics for theories with Lorentz symmetry violation. It appears possible to construct a perpetual motion machine of the second kind in such theories, using a black hole to catalyze the conversion of heat to work. Here we describe and extend the arguments leading to that conclusion. We suggest the inference that local Lorentz symmetry may be an emergent property of the macroscopic world with origins in a microsco...
Relabeling symmetries in hydrodynamics and magnetohydrodynamics
Energy Technology Data Exchange (ETDEWEB)
Padhye, N.; Morrison, P.J.
1996-04-01
Lagrangian symmetries and concomitant generalized Bianchi identities associated with the relabeling of fluid elements are found for hydrodynamics and magnetohydrodynamics (MHD). In hydrodynamics relabeling results in Ertel`s theorem of conservation of potential vorticity, while in MHD it yields the conservation of cross helicity. The symmetries of the reduction from Lagrangian (material) to Eulerian variables are used to construct the Casimir invariants of the Hamiltonian formalism.
The central role of symmetry in physics
Das, Saurya
2016-01-01
Spacetime and internal symmetries can be used to severely restrict the form of the equations for the fundamental laws of physics. The success of this approach in the context of general relativity and particle physics motivates the conjecture that symmetries may help us to one day uncover the ultimate theory that provides a unique, unified description of all observed physical phenomena. We examine some of the strengths and weaknesses of this conjecture.
Hidden symmetries of heterotic string theory
International Nuclear Information System (INIS)
Symmetries of two dimensional Heterotic string theory are studied following the approach of Kinnersley et. al. for the study of stationary axially-symmetric Einstein-Maxwell equations. The o(8,8)-circumflex and o (8,24)-circumflex symmetries of the heterotic string theory in the absence and presence, respectively, of the E8 X E8 backgrounds in two dimensions are pointed out. (author)
Symmetry energy in cold dense matter
Jeong, Kie Sang; Lee, Su Houng
2016-01-01
We calculate the symmetry energy in cold dense matter both in the normal quark phase and in the 2-color superconductor (2SC) phase. For the normal phase, the thermodynamic potential is calculated by using hard dense loop (HDL) resummation to leading order, where the dominant contribution comes from the longitudinal gluon rest mass. The effect of gluonic interaction on the symmetry energy, obtained from the thermodynamic potential, was found to be small. In the 2SC phase, the non-perturbative BCS paring gives enhanced symmetry energy as the gapped states are forced to be in the common Fermi sea reducing the number of available quarks that can contribute to the asymmetry. We used high density effective field theory to estimate the contribution of gluon interaction to the symmetry energy. Among the gluon rest masses in 2SC phase, only the Meissner mass has iso-spin dependence although the magnitude is much smaller than the Debye mass. As the iso-spin dependence of gluon rest masses is even smaller than the case in the normal phase, we expect that the contribution of gluonic interaction to the symmetry energy in the 2SC phase will be minimal. The different value of symmetry energy in each phase will lead to different prediction for the particle yields in heavy ion collision experiment.
Symmetry-improved CJT effective action
International Nuclear Information System (INIS)
The formalism introduced by Cornwall, Jackiw and Tomboulis (CJT) provides a systematic approach to consistently resumming non-perturbative effects in Quantum Thermal Field Theory. One major limitation of the CJT effective action is that its loopwise expansion introduces residual violations of possible global symmetries, thus giving rise to massive Goldstone bosons in the spontaneously broken phase of the theory. In this paper we develop a novel symmetry-improved CJT formalism for consistently encoding global symmetries in a loopwise expansion. In our formalism, the extremal solutions of the fields and propagators to a loopwise truncated CJT effective action are subject to additional constraints given by the Ward Identities due to global symmetries. By considering a simple O(2) scalar model, we show that, unlike other methods, our approach satisfies a number of important field-theoretic properties. In particular, we find that the Goldstone boson resulting from spontaneous symmetry breaking of O(2) is massless and the phase transition is a second-order one, already in the Hartree–Fock approximation. After taking the sunset diagrams into account, we show how our approach properly describes the threshold properties of the massless Goldstone boson and the Higgs particle in the loops. Finally, assuming minimal modifications to the Hartree–Fock approximated CJT effective action, we calculate the corresponding symmetry-improved CJT effective potential and discuss the conditions for its uniqueness for scalar-field values away from its minimum
Fluency Expresses Implicit Knowledge of Tonal Symmetry.
Ling, Xiaoli; Li, Fengying; Qiao, Fuqiang; Guo, Xiuyan; Dienes, Zoltan
2016-01-01
The purposes of the present study were twofold. First, we sought to establish whether tonal symmetry produces processing fluency. Second, we sought to explore whether symmetry and chunk strength express themselves differently in fluency, as an indication of different mechanisms being involved for sub- and supra-finite state processing. Across two experiments, participants were asked to listen to and memorize artificial poetry showing a mirror symmetry (an inversion, i.e., a type of cross serial dependency); after this training phase, people completed a four-choice RT task in which they were presented with new artificial poetry. Participants were required to identify the stimulus displayed. We found that symmetry sped up responding to the second half of strings, indicating a fluency effect. Furthermore, there was a dissociation between fluency effects arising from symmetry vs. chunk strength, with stronger fluency effects for symmetry rather than chunks in the second half of strings. Taken together, we conjecture a divide between finite state and supra-finite state mechanisms in learning grammatical sequences. PMID:26869960
A hidden classical symmetry of QCD
Glozman, L Ya
2016-01-01
The classical part of the QCD partition function (the integrand) has, ignoring irrelevant exact zero modes of the Dirac operator, a local SU(2N_F) \\supset SU(N_F)_L \\times SU(N_F)_R \\times U(1)_A symmetry which is absent at the Lagrangian level. This symmetry is broken anomalously and spontaneously. Effects of spontaneous breaking of chiral symmetry are contained in the near-zero modes of the Dirac operator. If physics of anomaly is also encoded in the same near-zero modes, then their truncation on the lattice should recover a hidden classical SU(2N_F) symmetry in correlators and spectra. This naturally explains observation on the lattice of a large degeneracy of hadrons, that is higher than the SU(N_F)_L \\times SU(N_F)_R \\times U(1)_A chiral symmetry, upon elimination by hands of the lowest-lying modes of the Dirac operator. We also discuss an implication of this symmetry for the high temperature QCD.
Hidden symmetries in five-dimensional supergravity
International Nuclear Information System (INIS)
This thesis is concerned with the study of hidden symmetries in supergravity, which play an important role in the present picture of supergravity and string theory. Concretely, the appearance of a hidden G2(+2)/SO(4) symmetry is studied in the dimensional reduction of d=5, N=2 supergravity to three dimensions - a parallel model to the more famous E8(+8)/SO(16) case in eleven-dimensional supergravity. Extending previous partial results for the bosonic part, I give a derivation that includes fermionic terms. This sheds new light on the appearance of the local hidden symmetry SO(4) in the reduction, and shows up an unusual feature which follows from an analysis of the R-symmetry associated with N=4 supergravity and of the supersymmetry variations, and which has no parallel in the eleven-dimensional case: The emergence of an additional SO(3) as part of the enhanced local symmetry, invisible in the dimensional reduction of the gravitino, and corresponding to the fact that, of the SO(4) used in the coset model, only the diagonal SO(3) is visible immediately upon dimensional reduction. The uncovering of the hidden symmetries proceeds via the construction of the proper coset gravity in three dimensions, and matching it with the Lagrangian obtained from the reduction. (orig.)
Local Conformal Symmetry: the Missing Symmetry Component for Space and Time
Hooft, Gerard T
2014-01-01
Local conformal symmetry is usually considered to be an approximate symmetry of nature, which is explicitly and badly broken. Arguments are brought forward here why it has to be turned into an exact symmetry that is spontaneously broken. As in the B.E.H. mechanism in Yang-Mills theories, we then will have a mechanism for disclosing the small-distance structure of the gravitational force. The symmetry could be as fundamental as Lorentz invariance, and guide us towards a complete understanding of physics at the ultra short distance scale.
Poisson Lie Group Symmetries for the Isotropic Rotator
Marmo, G; Stern, A
1995-01-01
We find a new Hamiltonian formulation of the classical isotropic rotator where left and right $SU(2)$ transformations are not canonical symmetries but rather Poisson Lie group symmetries. The system corresponds to the classical analog of a quantum mechanical rotator which possesses quantum group symmetries. We also examine systems of two classical interacting rotators having Poisson Lie group symmetries.
Perturbation of symmetries for super-long elastic slender rods
Institute of Scientific and Technical Information of China (English)
Ding Ning; Fang Jian-Hui
2011-01-01
This paper analyses perturbations of Noether symmetry,Lie symmetry,and form invariance for super-long elastic slender rod systems.Criterion and structure equations of the symmetries after disturbance are proposed.Considering perturbation of all infinitesimal generators,three types of adiabatic invariants induced by perturbation of symmetries for the system are obtained.
On Symmetry Flows of Noncommutative Kadomtsev-Petviashvili Hierarchy
International Nuclear Information System (INIS)
We discuss symmetry flows of noncommutative Kadomtsev-Petviashvili (NCKP) hierarchy. An operator-based formulation, alternative to the star-product approach of extended symmetry flows is presented. Noncommutative additional symmetry flows of the NCKP hierarchy are formulated. A rescaling symmetry flow which is associated with the rescaling of whole coordinates is introduced.
Symmetries of renormalized theories. 1. Non-gauge theories
International Nuclear Information System (INIS)
The symmetry properties of the renomalized filed theories the classical actions of which have symmetry properties are studied in the general form, when the jacobian of change of variables in the functional integral is not ignored. It is shown that to any symmetry of classical action corresponds a certain symmetry of renormalized quantum action and renormalized generating functional of proper vertices
On Symmetry Flows of Noncommutative Kadomtsev-Petviashvili Hierarchy
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
We discuss symmetry flows of noncommutative Kadomtsev-Petviashvili (NCKP) hierarchy. An operatorbased formulation, alternative to the star-product approach of extended symmetry flows is presented. Noncommutative additional symmetry flows of the NCKP hierarchy are formulated. A rescaling symmetry flow which is associated with the rescaling of whole coordinates is introduced.
2 and 3-dimensional Hamiltonians with Shape Invariance Symmetry
Jafarizadeh, M. A.; Panahi-Talemi, H.; Faizi, E.
2000-01-01
Via a special dimensional reduction, that is, Fourier transforming over one of the coordinates of Casimir operator of su(2) Lie algebra and 4-oscillator Hamiltonian, we have obtained 2 and 3 dimensional Hamiltonian with shape invariance symmetry. Using this symmetry we have obtained their eigenspectrum. In the mean time we show equivalence of shape invariance symmetry and Lie algebraic symmetry of these Hamiltonians.
Perturbation to Mei symmetry and adiabatic invariants for Hamilton systems
Institute of Scientific and Technical Information of China (English)
Ding Ning; Fang Jian-Hui
2008-01-01
Based on the concept of adiabatic invariant,this paper studies the perturbation to Mei symmetry and adiabatic invariants for Hamilton systems.The exact invaxiants of Mei symmetry for the system without perturbation are given.The perturbation to Mei symmetry is discussed and the adiabatic invariants induced from the perturbation to Mei symmetry of the system are obtained.
Perception of Mirror Symmetry in Autism Spectrum Disorders
Falter, Christine M.; Bailey, Anthony J.
2012-01-01
Gestalt grouping in autism spectrum disorders (ASD) is selectively impaired for certain organization principles but for not others. Symmetry is a fundamental Gestalt principle characterizing many biological shapes. Sensitivity to symmetry was tested using the Picture Symmetry Test, which requires finding symmetry lines on pictures. Individuals…
At the origins of mass: elementary particles and fundamental symmetries
International Nuclear Information System (INIS)
After a brief recall of the history of cosmology, the author proposes an overview of the different symmetries (symmetries in space and in time, internal symmetries, local or gauge symmetries), describes the mass issue (gauge interactions, quarks and leptons as matter mass constituents, chirality), addresses the spontaneous symmetry breaking (the Curie theorem, spontaneous symmetry breaking in classical physics and in quantum physics, the Goldstone theorem, spontaneous symmetry breaking in presence of gauge interactions), presents the standard theory (electromagnetic and weak interactions, strong interactions, relationship with experiment). An appendix presents elementary particles, and notably reports the story of the neutrino
Pseudospin Symmetry as a Bridge between Hadrons and Nuclei
Directory of Open Access Journals (Sweden)
Joseph N. Ginocchio
2016-03-01
Full Text Available Atomic nuclei exhibit approximate pseudospin symmetry. We review the arguments that this symmetry is a relativistic symmetry. The condition for this symmetry is that the sum of the vector and scalar potentials in the Dirac Hamiltonian is a constant. We give the generators of pseudospin symmetry. We review some of the predictions that follow from the insight that pseudospin symmetry has relativistic origins . We show that approximate pseudospin symmetry in nuclei predicts approximate spin symmetry in anti-nucleon scattering from nuclei. Since QCD sum rules predict that the sum of the scalar and vector potentials is small, we discuss the quark origins of pseudospin symmetry in nuclei and spin symmetry in hadrons.
Spectral signatures of high-symmetry quantum dots and effects of symmetry breaking
Karlsson, K. F.; Oberli, D. Y.; Dupertuis, M. A.; Troncale, V.; Byszewski, M.; Pelucchi, E.; Rudra, A.; Holtz, P. O.; Kapon, E.
2015-10-01
High symmetry epitaxial quantum dots (QDs) with three or more symmetry planes provide a very promising route for the generation of entangled photons for quantum information applications. The great challenge to fabricate nanoscopic high symmetry QDs is further complicated by the lack of structural characterization techniques able to resolve small symmetry breaking. In this work, we present an approach for identifying and analyzing the signatures of symmetry breaking in the optical spectra of QDs. Exciton complexes in InGaAs/AlGaAs QDs grown along the [111]B crystalline axis in inverted tetrahedral pyramids are studied by polarization resolved photoluminescence spectroscopy combined with lattice temperature dependence, excitation power dependence and temporal photon correlation measurements. By combining such a systematic experimental approach with a simple theoretical approach based on a point-group symmetry analysis of the polarized emission patterns of each exciton complex, we demonstrate that it is possible to achieve a strict and coherent identification of all the observable spectral patterns of numerous exciton complexes and a quantitative determination of the fine structure splittings of their quantum states. This analysis is found to be particularly powerful for selecting QDs with the highest degree of symmetry (C3v and {D}3h) for potential applications of these QDs as polarization entangled photon sources. We exhibit the optical spectra when evolving towards asymmetrical QDs, and show the higher sensitivity of certain exciton complexes to symmetry breaking.
Quaternion-Octonion Unitary Symmetries and Analogous Casimir Operators
Pushpa,; Li, Tianjun; Negi, O P S
2012-01-01
An attempt has been made to investigate the global SU(2) and SU(3) unitary flavor symmetries systematically in terms of quaternion and octonion respectively. It is shown that these symmetries are suitably handled with quaternions and octonions in order to obtain their generators, commutation rules and symmetry properties. Accordingly, Casimir operators for SU(2)and SU(3) flavor symmetries are also constructed for the proper testing of these symmetries in terms of quaternions and octonions.
Neutrino Hierarchies from a Gauge Symmetry
Heeck, Julian
2012-01-01
We consider the phenomenology of the gauged abelian symmetry B + 3 (L_e - L_mu - L_tau). Right-handed neutrinos necessary to cancel triangle anomalies are used in a type-I seesaw scheme to create active neutrino masses. Breaking the B + 3 (L_e - L_mu - L_tau) symmetry spontaneously below the seesaw scale generates low energy neutrino mass matrices with the approximate symmetries L_e (leading to normal hierarchy) or L_e - L_mu - L_tau (inverted hierarchy). For the latter we need to introduce a Z_2 symmetry which decouples one of the right-handed neutrinos. Accidently, the Z_2 makes it a dark matter candidate that interacts with the Standard Model via the Z' and a scalar s originating from spontaneous breaking of the new symmetry. The measured relic abundance of the Majorana dark matter particle can be obtained around the scalar and Z' resonances, while direct detection experiments are mainly sensitive to scalar exchange, which is induced by mass mixing of s with the standard Higgs.
Dynamical symmetries of the shell model
International Nuclear Information System (INIS)
The applications of spectrum generating algebras and of dynamical symmetries in the nuclear shell model are many and varied. They stretch back to Wigner's early work on the supermultiplet model and encompass important landmarks in our understanding of the structure of the atomic nucleus such as Racah's SU(2) pairing model and Elliot's SU(3) rotational model. One of the aims of this contribution has been to show the historical importance of the idea of dynamical symmetry in nuclear physics. Another has been to indicate that, in spite of being old, this idea continues to inspire developments that are at the forefront of today's research in nuclear physics. It has been argued in this contribution that the main driving features of nuclear structure can be represented algebraically but at the same time the limitations of the symmetry approach must be recognised. It should be clear that such approach can only account for gross properties and that any detailed description requires more involved numerical calculations of which we have seen many fine examples during this symposium. In this way symmetry techniques can be used as an appropriate starting point for detailed calculations. A noteworthy example of this approach is the pseudo-SU(3) model which starting from its initial symmetry Ansatz has grown into an adequate and powerful description of the nucleus in terms of a truncated shell model. (author)
Seiberg duality versus hidden local symmetry
Abel, Steven
2012-01-01
It is widely believed that the emergent magnetic gauge symmetry of SQCD is analogous to a hidden local symmetry (HLS). We explore this idea in detail, deriving the entire (spontaneously broken) magnetic theory by applying the HLS formalism to spontaneously broken SU(N) SQCD. We deduce the K\\"ahler potential in the HLS description, and show that gauge and flavour symmetry are smoothly restored along certain scaling directions in moduli space. We propose that it is these symmetry restoring directions, associated with the R-symmetry of the theory, that allow full Seiberg duality. Reconsidering the origin of the magnetic gauge bosons as the rho-mesons of the electric theory, colour-flavour locking allows a simple determination of the parameter "a". Its value continuously interpolates between a=2 on the baryonic branch of moduli space - corresponding to "vector meson dominance" - and a=1 on the mesonic branch. Both limiting values are consistent with previous results in the literature. The HLS formalism is further...
The symmetries of the Carroll superparticle
Bergshoeff, Eric; Gomis, Joaquim; Parra, Lorena
2016-05-01
Motivated by recent applications of Carroll symmetries we investigate, using the method of nonlinear realizations, the geometry of flat and curved (AdS) Carroll space and the symmetries of a particle moving in such a space both in the bosonic as well as in the supersymmetric case. In the bosonic case we find that the Carroll particle possesses an infinite-dimensional symmetry which only in the flat case includes dilatations. The duality between the Bargmann and Carroll algebra, relevant for the flat case, does not extend to the curved case. In the supersymmetric case we study the dynamics of the { N }=1 AdS Carroll superparticle. Only in the flat limit we find that the action is invariant under an infinite-dimensional symmetry that includes a supersymmetric extension of the Lifshitz Carroll algebra with dynamical exponent z = 0. We also discuss in the flat case the extension to { N }=2 supersymmetry and show that the flat { N }=2 superparticle is equivalent to the (non-moving) { N }=1 superparticle and that therefore it is not BPS unlike its Galilei counterpart. This is due to the fact that in this case kappa-symmetry eliminates the linearized supersymmetry. In an appendix we discuss the { N }=2 curved case in three-dimensions only and show that there are two { N }=2 theories that are physically different.
Translational spacetime symmetries in gravitational theories
International Nuclear Information System (INIS)
How to include spacetime translations in fibre bundle gauge theories has been a subject of controversy, because spacetime symmetries are not internal symmetries of the bundle structure group. The standard method for including affine symmetry in differential geometry is to define a Cartan connection on an affine bundle over spacetime. This is equivalent to (1) defining an affine connection on the affine bundle, (2) defining a zero section on the associated affine vector bundle and (3) using the affine connection and the zero section to define an 'associated solder form', whose lift to a tensorial form on the frame bundle becomes the solder form. The zero section reduces the affine bundle to a linear bundle and splits the affine connection into translational and homogeneous parts; however, it violates translational equivariance/gauge symmetry. This is the natural geometric framework for Einstein-Cartan theory as an affine theory of gravitation. The last section discusses some alternative approaches that claim to preserve translational gauge symmetry
Quasi Hopf quantum symmetry in quantum theory
International Nuclear Information System (INIS)
In quantum theory, internal symmetries more general than groups are possible. We show that quasitriangular quasi Hopf algebras G* as introduced by Drinfeld permit a consistent formulation of a transformation law of states in the physical Hilbert space H, of invariance of the ground state, and of a transformation law of field operators which is consistent with local braid relations of field operators as proposed by Froehlich. All this remains true when Drinfelds axioms are suitably weakened in order to build in truncated tensor products. Conversely, all the axioms of a weak quasitriangular quasi Hopf algebra are motivated from what physics demands of a symmetry. Unitarity requires in addition that G* admits a*-operation with certain properties. Invariance properties of Greens functions follow from invariance of the ground state and covariance of field operators as usual. Covariant adjoints and covariant products of field operators can be defined. The R-matrix elements in the local braid relations are in general operators in H. They are determined by the symmetry up to a phase factor. Quantum group algebras like Uq(sl2) with vertical strokeqvertical stroke=1 are examples of symmetries with special properties. We show that a weak quasitriangular quasi Hopf algebra G* is canonically associated with Uq(sl2) if qP=-1. We argue that these weak quasi Hopf algebras are the true symmetries of minimal conformal models. Their dual algebras G ('functions on the group') are neither commutative nor associative. (orig.)
Quasi Hopf quantum symmetry in quantum theory
International Nuclear Information System (INIS)
In quantum theory, internal symmetries more general than groups are possible. We show that quasi-triangular quasi Hopf algebras G* ('quasi quantum groups') permit a consistent formulation of a transformation law of states in the physical Hilbert space H, of invariance of the ground state, and of a transformation law of field operators which is consistent with local braid relations of field operators. All this remains true when Drinfeld's axioms are suitably weakened in order to build in truncated tensor products. Conversely, all the axioms of a weak quasi-triangular quasi Hopf algebra are motivated from what physics demands of a symmetry. Unitarity requires in addition that G* admits a *-operation with certain properties. Invariance properties of Green functions follow from invariance of the ground state and covariance of field operators as usual. Covariant adjoints and covariant products of field operators can be defined. The R-matrix elements in the local braid relations are in general operators in H. They are determined by the symmetry up to a phase factor. Quantum group algebras like Uq(sl2) with vertical strokeqvertical stroke=1 are examples of symmetries with special properties. We show that a weak quasi-triangular quasi Hopf algebra G* is canonically associated with Uq(sl2) if qp=1. We argue that these weak quasi Hopf algebras are the true symmetries of minimal conformal models. Their dual algebras G ('functions on the group') are neither commutative nor associative. (orig.)
Symmetry in social exchange and health
Siegrist, Johannes
2005-10-01
Symmetry is a relevant concept in sociological theories of exchange. It is rooted in the evolutionary old norm of social reciprocity and is particularly important in social contracts. Symmetry breaking through violation of the norm of reciprocity generates strain in micro-social systems and, above all, in victims of non-symmetric exchange. In this contribution, adverse healthconsequences of symmetry breaking in contractual social exchange are analysed, with a main focus on the employment contract. Scientific evidence is derived from prospective epidemiological studies testing the model of effort-reward imbalance at work. Overall, a twofold elevated risk of incident disease is observed in employed men and women who are exposed to non-symmetric exchange. Health risks include coronary heart disease, depression and alcohol dependence, among others. Preliminary results suggest similar effects on health produced by symmetry breaking in other types of social relationships (e.g. partnership, parental roles). These findings underline the importance of symmetry in contractual social exchange for health and well-being.
Dynamical symmetries of the shell model
Energy Technology Data Exchange (ETDEWEB)
Van Isacker, P
2000-07-01
The applications of spectrum generating algebras and of dynamical symmetries in the nuclear shell model are many and varied. They stretch back to Wigner's early work on the supermultiplet model and encompass important landmarks in our understanding of the structure of the atomic nucleus such as Racah's SU(2) pairing model and Elliot's SU(3) rotational model. One of the aims of this contribution has been to show the historical importance of the idea of dynamical symmetry in nuclear physics. Another has been to indicate that, in spite of being old, this idea continues to inspire developments that are at the forefront of today's research in nuclear physics. It has been argued in this contribution that the main driving features of nuclear structure can be represented algebraically but at the same time the limitations of the symmetry approach must be recognised. It should be clear that such approach can only account for gross properties and that any detailed description requires more involved numerical calculations of which we have seen many fine examples during this symposium. In this way symmetry techniques can be used as an appropriate starting point for detailed calculations. A noteworthy example of this approach is the pseudo-SU(3) model which starting from its initial symmetry Ansatz has grown into an adequate and powerful description of the nucleus in terms of a truncated shell model. (author)
Geometrical symmetries of nuclear systems: {{ D }}_{3h} and {{ T }}_{d} symmetries in light nuclei
Bijker, Roelof
2016-07-01
The role of discrete (or point-group) symmetries in α-cluster nuclei is discussed in the framework of the algebraic cluster model which describes the relative motion of the α-particles. Particular attention is paid to the discrete symmetry of the geometric arrangement of the α-particles, and the consequences for the structure of the corresponding rotational bands. The method is applied to study cluster states in the nuclei 12C and 16O. The observed level sequences can be understood in a simple way as a consequence of the underlying discrete symmetry that characterizes the geometrical configuration of the α-particles, i.e. an equilateral triangle with {{ D }}3h symmetry for 12C, and a tetrahedron with {{ T }}d symmetry for 16O. The structure of rotational bands provides a fingerprint of the underlying geometrical configuration of α-particles.
On the symmetry of the vacuum in theories with spontaneous symmetry breaking
Perez, Alejandro
2008-01-01
We review the usual account of the phenomena of spontaneous symmetry breaking (SSB), pointing out the common misunderstandings surrounding the issue, in particular within the context of quantum field theory. In fact, the common explanations one finds in this context, indicate that under certain conditions corresponding to the situation called SSB, the vacuum of the theory does not share the symmetries of the Lagrangian. We explain in detail why this statement is incorrect in general, and in what limited set of circumstances such situation could arise. We concentrate on the case of global symmetries, for which we found no satisfactory exposition in the existing literature, and briefly comment on the case of gauge symmetries where, although insufficiently publicized, accurate and complete descriptions exist. We briefly discuss the implications for the phenomenological manifestations usually attributed to the phenomena of spontaneous symmetry breaking, analyzing which might be affected by our analysis and which ...
Geometrical symmetries of nuclear systems: D(3h) and T(d) symmetries in light nuclei
Bijker, Roelof
2016-01-01
The role of discrete (or point-group) symmetries in alpha-cluster nuclei is discussed in the framework of the algebraic cluster model which describes the relative motion of the alpha-particles. Particular attention is paid to the discrete symmetry of the geometric arrangement of the alpha-particles, and the consequences for the structure of the corresponding rotational bands. The method is applied to study cluster states in the nuclei 12C and 16O. The observed level sequences can be understood in a simple way as a consequence of the underlying discrete symmetry that characterizes the geometrical configuration of the alpha-particles, i.e. an equilateral triangle with D(3h) symmetry for 12C, and a tetrahedron with T(d) symmetry for 16O. The structure of rotational bands provides a fingerprint of the underlying geometrical configuration of alpha-particles.
Symmetry-protected topological phases in noninteracting fermion systems
Wen, Xiao-Gang
2012-02-01
Symmetry-protected topological (SPT) phases are gapped quantum phases with a certain symmetry, which can all be smoothly connected to the same trivial product state if we break the symmetry. For noninteracting fermion systems with time reversal (T̂), charge conjugation (Ĉ), and/or U(1) (N̂) symmetries, the total symmetry group can depend on the relations between those symmetry operations, such as T̂N̂T̂-1=N̂ or T̂N̂T̂-1=-N̂. As a result, the SPT phases of those fermion systems with different symmetry groups have different classifications. In this paper, we use Kitaev's K-theory approach to classify the gapped free-fermion phases for those possible symmetry groups. In particular, we can view the U(1) as a spin rotation. We find that superconductors with the Sz spin-rotation symmetry are classified by Z in even dimensions, while superconductors with the time reversal plus the Sz spin-rotation symmetries are classified by Z in odd dimensions. We show that all 10 classes of gapped free-fermion phases can be realized by electron systems with certain symmetries. We also point out that, to properly describe the symmetry of a fermionic system, we need to specify its full symmetry group that includes the fermion number parity transformation (-)N̂. The full symmetry group is actually a projective symmetry group.
Symmetry-related decompositions of uncertainty
Viana, Marlos
2012-10-01
In statistics, the sample mean and variance are intimately related to the symmetries of the full symmetric group describing all possible permutations of assignments of observations to sampling units. While those symmetries yield exactly two invariant subspaces (in a sense to be defined in the text) in correspondence to those summary statistics, the invariant subspaces associated with specific subgroups of the full symmetric group may then lead to much detailed decompositions of the experimental uncertainty. In the present chapter we discuss the symmetry-related summaries of data arising from dihedral experiments, specifically in the context of multinomial models for frequency counts in symbolic sequences. Special examples are given to dihedral summaries that can be potentially interpreted as measures of (molecular) chirality or handedness.
Crystallography and the world of symmetry
Chatterjee, Sanat K
2008-01-01
Symmetry exists in realms from crystals to patterns, in external shapes of living or non-living objects, as well as in the fundamental particles and the physical laws that govern them. In fact, the search for this symmetry is the driving force for the discovery of many fundamental particles and the formulation of many physical laws. While one can not imagine a world which is absolutely symmetrical nor can one a world which is absolutely asymmetrical. These two aspects of nature are intermingled with each other inseparably. This is the basis of the existence of aperiodicity manifested in the liquid crystals and also quasi-crystals also discussed in Crystallography and the World of Symmetry.
Discrete Abelian gauge symmetries and axions
Honecker, Gabriele
2015-01-01
We combine two popular extensions of beyond the Standard Model physics within the framework of intersecting D6-brane models: discrete Zn symmetries and Peccei-Quinn axions. The underlying natural connection between both extensions is formed by the presence of massive U(1) gauge symmetries in D-brane model building. Global intersecting D6-brane models on toroidal orbifolds of the type T6/Z2N and T6/Z2xZ2M with discrete torsion offer excellent playgrounds for realizing these extensions. A generation-dependent Z2 symmetry is identified in a global Pati-Salam model, while global left-right symmetric models give rise to supersymmetric realizations of the DFSZ axion model. In one class of the latter models, the axion as well as Standard Model particles carry a non-trivial Z3 charge.
Workshop on electroweak symmetry breaking: proceedings
International Nuclear Information System (INIS)
A theoretical workshop on electroweak symmetry breaking at the Superconducting Supercollider was held at Lawrence Berkeley Laboratory, June 4-22, 1984. The purpose of the workshop was to focus theoretical attention on the ways in which experimentation at the SSC could reveal manifestations of the phenomenon responsible for electroweak symmetry breaking. This issue represents, at present, the most compelling scientific argument for the need to explore the energy region to be made accessible by the SSC, and a major aim of the workshop was to involve a broad cross section of particle theorists in the ongoing process of sharpening the requirements for both accelerator and detector design that will ensure detection and identification of meaningful signals, whatever form the electroweak symmetry breaking phenomenon should actually take. Separate entries were prepared for the data base for the papers presented
Topological phases with generalized global symmetries
Yoshida, Beni
2016-04-01
We present simple lattice realizations of symmetry-protected topological phases with q -form global symmetries where charged excitations have q spatial dimensions. Specifically, we construct d space-dimensional models supported on a (d +1 ) -colorable graph by using a family of unitary phase gates, known as multiqubit control-Z gates in quantum information community. In our construction, charged excitations of different dimensionality may coexist and form a short-range entangled state which is protected by symmetry operators of different dimensionality. Nontriviality of proposed models, in a sense of quantum circuit complexity, is confirmed by studying protected boundary modes, gauged models, and corresponding gapped domain walls. We also comment on applications of our construction to quantum error-correcting codes, and discuss corresponding fault-tolerant logical gates.
Twin and Mirror Symmetries from Presymmetry
Matute, Ernesto A
2011-01-01
We argue that presymmetry, a hidden predynamical electroweak quark-lepton symmetry that explains the fractional charges and triplication of families, must be extended beyond the Standard Model as to have a residual presymmetry that embraces partner particles and includes the strong sector, so accounting for the twin or mirror partners proposed to alleviate the naturalness problem of the weak scale. It leads to the full duplication of fermions and gauge bosons of the Standard Model independently of the ultraviolet completion of the theory, even if the Higgs particle is discarded by experiment, which adds robustness to twin and mirror symmetries. The established connection is so strongly motivated that the search for twin or mirror matter becomes the possible test of presymmetry. If the physics beyond the Standard Model repairs its left-right asymmetry, mirror symmetry should be the one realized in nature.
Automorphic Lie algebras with dihedral symmetry
International Nuclear Information System (INIS)
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 sl2(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 this 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. (paper)
Nuclear symmetry energy from QCD sum rules
International Nuclear Information System (INIS)
We calculated the nucleon self-energies in iso-spin asymmetric nuclear matter and obtained the nuclear symmetry energy by taking difference of these of neutron and proton. We find that the scalar (vector) self-energy part gives a negative (positive) contribution to the nuclear symmetry energy, consistent with the result from relativistic mean-field theories. Also, we found exact four-quark operator product expansion for nucleon sum rule. Among them, twist-4 matrix elements which can be extracted from deep inelastic scattering experiment constitute an essential part in the origin of the nuclear symmetry energy from QCD. Our result also extends early success of QCD sum rule in the symmetric nuclear matter to the asymmetric nuclear matter. (authors)
Homological mirror symmetry and tropical geometry
Catanese, Fabrizio; Kontsevich, Maxim; Pantev, Tony; Soibelman, Yan; Zharkov, Ilia
2014-01-01
The relationship between Tropical Geometry and Mirror Symmetry goes back to the work of Kontsevich and Y. Soibelman (2000), who applied methods of non-archimedean geometry (in particular, tropical curves) to Homological Mirror Symmetry. In combination with the subsequent work of Mikhalkin on the “tropical” approach to Gromov-Witten theory, and the work of Gross and Siebert, Tropical Geometry has now become a powerful tool. Homological Mirror Symmetry is the area of mathematics concentrated around several categorical equivalences connecting symplectic and holomorphic (or algebraic) geometry. The central ideas first appeared in the work of Maxim Kontsevich (1993). Roughly speaking, the subject can be approached in two ways: either one uses Lagrangian torus fibrations of Calabi-Yau manifolds (the so-called Strominger-Yau-Zaslow picture, further developed by Kontsevich and Soibelman) or one uses Lefschetz fibrations of symplectic manifolds (suggested by Kontsevich and further developed by Seidel). Tropical Ge...
Gauge and space-time symmetry unification
Besprosvany, J
2000-01-01
Unification ideas suggest an integral treatment of fermion and boson spin and gauge-group degrees of freedom. Hence, a generalized quantum field equation, based on Dirac's, is proposed and investigated which contains gauge and flavor symmetries, determines vector gauge field and fermion solution representations, and fixes their mode of interaction. The simplest extension of the theory with a 6-dimensional Clifford algebra predicts an SU(2)_L X U(1) symmetry, which is associated with the isospin and the hypercharge, their vector carriers, two-flavor charged and chargeless leptons, and scalar particles. A mass term produces breaking of the symmetry to an electromagnetic U(1), and a Weinberg's angle theta_W with sin^2(theta_W)=.25 . A more realistic 8-d extension gives coupling constants of the respective groups g=1/sqrt 2~.707 and g'=1/sqrt 6~.408, with the same theta_W.
Symmetry issues in Directly Irradiated Targets
Directory of Open Access Journals (Sweden)
Ramis R.
2013-11-01
Full Text Available In direct drive Inertial Confinement Fusion (ICF, the typical laser beam to laser beam angle is around 30°. This fact makes the study of the irradiation symmetry a genuine 3D problem. In this paper we use the three dimensional version of the MULTI hydrocode to assess the symmetry of such ICF implosions. More specifically, we study a shock-ignition proposal for the Laser-Mégajoule facility (LMJ in which two of the equatorial beam cones are used to implode and precompress a spherical capsule (the “reference” capsule of HiPER project made of 0.59 mg of pure Deuterium-Tritium mixture. The symmetry of this scheme is analysed and optimized to get a design inside the operating limits of LMJ. The studied configuration has been found essentially axial-symmetric, so that the use of 2D hydrocodes would be appropriate for this specific situation.
Symmetries and pre-metric electromagnetism
Delphenich, D
2005-01-01
The equations of pre-metric electromagnetism are formulated as an exterior differential system on the bundle of exterior differential 2-forms over the spacetime manifold. The general form for the symmetry equations of the system is computed and then specialized to various possible forms for an electromagnetic constitutive law, namely, uniform linear, non-uniform linear, and uniform nonlinear. It is shown that in the uniform linear case, one has four possible ways of prolonging the symmetry Lie algebra, including prolongation to a Lie algebra of infinitesimal projective transformations of a real four-dimensional projective space. In the most general non-uniform linear case, th effect of non-uniformity on symmetry seems inconclusive in the absence of further specifics, and in the uniform nonlinear case, the overall difference from the uniform linear case amounts to a deformation of the electromagnetic constitutive tensor by the electromagnetic fields strengths, which induces a corresponding deformation of the s...
Medium effect on charge symmetry breaking
International Nuclear Information System (INIS)
We examine the nuclear medium effect on charge symmetry breaking (CSB) caused by isospin mixing of two neutral vector mesons interacting with nucleons in the nuclear medium. Isospin mixing is assumed to occur through the transition between isoscalar and isovector mesons. We use a quantum hadrodynamic nuclear model in the mean-field approximation for the meson fields involved. We find that (i) charge symmetry is gradually restored in nuclear matter in β equilibrium as the nucleon density increases; (ii) when the system departs from β equilibrium, CSB is much enhanced because the isospin mixing depends strongly on the nucleon isovector density; (iii) this leads to the symmetry energy coefficient of 32MeV, of which more than 50 percent arises from the mesonic mean fields; (iv) the Nolen-Schiffer anomaly regarding the masses of neighboring mirror nuclei can be resolved by considering these aspects of CSB in nuclear medium. copyright 1997 The American Physical Society
Symmetry and Resonance in Periodic FPU Chains
Rink, Bob
The symmetry and resonance properties of the Fermi Pasta Ulam chain with periodic boundary conditions are exploited to construct a near-identity transformation bringing this Hamiltonian system into a particularly simple form. This ``Birkhoff-Gustavson normal form'' retains the symmetries of the original system and we show that in most cases this allows us to view the periodic FPU Hamiltonian as a perturbation of a nondegenerate Liouville integrable Hamiltonian. According to the KAM theorem this proves the existence of many invariant tori on which motion is quasiperiodic. Experiments confirm this qualitative behaviour. We note that one can not expect this in lower-order resonant Hamiltonian systems. So the periodic FPU chain is an exception and its special features are caused by a combination of special resonances and symmetries.
Arithmetic crystal classes of magnetic symmetries
International Nuclear Information System (INIS)
The symmetries and properties of a broad class of magnetic crystals are described by magnetic space groups which contain both (unitary) spatial symmetry operations and their combinations with the (anti-unitary operation of) time inversion, 0. The spatial symmetry operations form a halving, non-magnetic, space group H of the magnetic group M such that M=H+aH. As an abstract group the magnetic group M is isomorphic to a non-magnetic group G. The anti-unitary operator a is simply the time inversion 0 when M is a grey group but a product of time inversion with some spatial operation belonging to the coset G-H when M is a black-and-white group. (Author)
Facial symmetry assessment based on geometric features
Xu, Guoping; Cao, Hanqiang
2015-12-01
Face image symmetry is an important factor affecting the accuracy of automatic face recognition. Selecting high symmetrical face image could improve the performance of the recognition. In this paper, we proposed a novel facial symmetry evaluation scheme based on geometric features, including centroid, singular value, in-plane rotation angle of face and the structural similarity index (SSIM). First, we calculate the value of the four features according to the corresponding formula. Then, we use fuzzy logic algorithm to integrate the value of the four features into a single number which represents the facial symmetry. The proposed method is efficient and can adapt to different recognition methods. Experimental results demonstrate its effectiveness in improving the robustness of face detection and recognition.
Workshop on electroweak symmetry breaking: proceedings
Energy Technology Data Exchange (ETDEWEB)
Hinchliffe, I. (ed.)
1984-10-01
A theoretical workshop on electroweak symmetry breaking at the Superconducting Supercollider was held at Lawrence Berkeley Laboratory, June 4-22, 1984. The purpose of the workshop was to focus theoretical attention on the ways in which experimentation at the SSC could reveal manifestations of the phenomenon responsible for electroweak symmetry breaking. This issue represents, at present, the most compelling scientific argument for the need to explore the energy region to be made accessible by the SSC, and a major aim of the workshop was to involve a broad cross section of particle theorists in the ongoing process of sharpening the requirements for both accelerator and detector design that will ensure detection and identification of meaningful signals, whatever form the electroweak symmetry breaking phenomenon should actually take. Separate entries were prepared for the data base for the papers presented.
Discrete Abelian gauge symmetries and axions
Honecker, Gabriele; Staessens, Wieland
2015-07-01
We combine two popular extensions of beyond the Standard Model physics within the framework of intersecting D6-brane models: discrete ℤn symmetries and Peccei-Quinn axions. The underlying natural connection between both extensions is formed by the presence of massive U(1) gauge symmetries in D-brane model building. Global intersecting D6-brane models on toroidal orbifolds of the type T6/ℤ2N and T6/ℤ2 × ℤ2M with discrete torsion offer excellent playgrounds for realizing these extensions. A generation-dependent ℤ2 symmetry is identified in a global Pati-Salam model, while global left-right symmetric models give rise to supersymmetric realizations of the DFSZ axion model. In one class of the latter models, the axion as well as Standard Model particles carry a non-trivial ℤ3 charge.
Gauging Unbroken Symmetries in F-theory
Ju, Chia-Yi
2016-01-01
F-theory attempts to include all U-dualities manifestly. Unlike its T-dual manifest partner, which is based on string current algebra, F-theory is based on higher dimensional brane current algebra. Like the T-dual manifest theory, which has $O(D-1,1)^2$ unbroken symmetry, the F-theory vacuum also enjoys certain symmetries ("$H$"). One of its important and exotic properties is that worldvolume indices are also spacetime indices. This makes the global brane current algebra incompatible with $H$ symmetry currents. The solution is to introduce worldvolume covariant derivatives, which depend on the $H$ coordinates even in a "flat" background. We will also give as an explicit example the 5-brane case.
Hidden symmetries in two dimensional field theory
International Nuclear Information System (INIS)
The bosonization process elegantly shows the equivalence of massless scalar and fermion fields in two space-time dimensions. However, with multiple fermions the technique often obscures global symmetries. Witten's non-Abelian bosonization makes these symmetries explicit, but at the expense of a somewhat complicated bosonic action. Frenkel and Kac have presented an intricate mathematical formalism relating the various approaches. Here, I reduce these arguments to the simplest case of a single massless scalar field. In particular, using only elementary quantum field theory concepts, I expose a hidden SU (2) x SU (2) chiral symmetry in this trivial theory. I then discuss in what sense this field should be interpreted as a Goldstone boson
Symmetries and groups in particle physics
International Nuclear Information System (INIS)
The aim of this book consists of a didactic introduction to the group-theoretical considerations and methods, which have led to an ever deeper understanding of the interactions of the elementary particles. The first three chapters deal primarily with the foundations of the representation theory of primarily finite groups, whereby many results are also transferable to compact Lie groups. In the third chapter we discuss the concept of Lie groups and their connection with Lie algebras. In the remaining chapter it is mainly about the application of group theory in physics. Chapter 4 deals with the groups SO(3) and SU(2), which occur in connection with the description of the angular momentum in quantum mechanics. We discuss the Wigner-Eckar theorem together with some applications. In chapter 5 we are employed to the composition properties of strongly interacting systems, so called hadrons, and discuss extensively the transformation properties of quarks with relation to the special unitary groups. The Noether theorem is generally treated in connection to the conservation laws belonging to the Galilei group and the Poincare group. We confine us in chapter 6 to internal symmetries, but explain for that extensively the application to quantum field theory. Especially an outlook on the effect of symmetries in form of so called Ward identities is granted. In chapter 7 we turn towards the gauge principle and discuss first the construction of quantum electrodynamics. In the following we generalize the gauge principle to non-Abelian groups (Yang-Mills theories) and formulate the quantum chromodynamics (QCD). Especially we take a view of ''random'' global symmetries of QCD, especially the chiral symmetry. In chapter 8 we illuminate the phenomenon of spontaneous symmetry breaking both for global and for local symmetries. In the final chapter we work out the group-theoretical structure of the Standard Model. Finally by means of the group SU(5) we take a view to
Symmetry in bonding and spectra an introduction
Douglas, Bodie E
1985-01-01
Many courses dealing with the material in this text are called ""Applications of Group Theory."" Emphasizing the central role and primary importance of symmetry in the applications, Symmetry in Bonding and Spectra enables students to handle applications, particularly applications to chemical bonding and spectroscopy. It contains the essential background in vectors and matrices for the applications, along with concise reviews of simple molecular orbital theory, ligand field theory, and treatments of molecular shapes, as well as some quantum mechanics. Solved examples in the text illustra