Frictional sliding with geometrically broken reflection symmetry
Aldam, Michael; Svetlizky, Ilya; Brener, Efim A; Fineberg, Jay; Bouchbinder, Eran
2016-01-01
The dynamics of frictional interfaces play an important role in many physical systems spanning a broad range of scales. It is well-known that frictional interfaces separating two dissimilar materials couple interfacial slip and normal stress variations, a coupling that has major implications on their stability, failure mechanism and rupture directionality. In contrast, interfaces separating identical materials are traditionally assumed not to feature such a coupling due to symmetry considerations. We show, combining theory and experiments, that interfaces which separate bodies made of identical materials, but lack geometric reflection symmetry, generically feature such a coupling. We discuss two applications of this novel feature. First, we show that it accounts for a distinct and previously unexplained weakening effect in frictional cracks observed experimentally. Second, we demonstrate that it can destabilize frictional sliding which is otherwise stable. The emerging framework is expected to find applicatio...
Entanglement entropy in quantum spin chains with broken reflection symmetry
Kadar, Zoltan
2010-01-01
We investigate the entanglement entropy of a block of L sites in quasifree translation-invariant spin chains concentrating on the effect of reflection symmetry breaking. The majorana two-point functions corresponding to the Jordan-Wigner transformed fermionic modes are determined in the most general case; from these it follows that reflection symmetry in the ground state can only be broken if the model is quantum critical. The large L asymptotics of the entropy is calculated analytically for general gauge-invariant models, which has, until now, been done only for the reflection symmetric sector. Analytical results are also derived for certain non-gauge-invariant models, e.g. for the Ising model with Dzyaloshinskii-Moriya interaction. We also study numerically finite chains of length N with a non-reflection-symmetric Hamiltonian and report that the reflection symmetry of the entropy of the first L spins is violated but the reflection-symmetric Calabrese-Cardy formula is recovered asymptotically. Furthermore, f...
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.
Invariants of broken discrete symmetries
Kalozoumis, P; Diakonos, F K; Schmelcher, P
2014-01-01
The parity and Bloch theorems are generalized to the case of broken global symmetry. Local inversion or translation symmetries are shown to yield invariant currents that characterize wave propagation. These currents map the wave function from an arbitrary spatial domain to any symmetry-related domain. Our approach addresses any combination of local symmetries, thus applying in particular to acoustic, optical and matter waves. Nonvanishing values of the invariant currents provide a systematic pathway to the breaking of discrete global symmetries.
Invariants of broken discrete symmetries
Kalozoumis, P.; Morfonios, C.; Diakonos, F. K.; Schmelcher, P.
2014-01-01
The parity and Bloch theorems are generalized to the case of broken global symmetry. Local inversion or translation symmetries are shown to yield invariant currents that characterize wave propagation. These currents map the wave function from an arbitrary spatial domain to any symmetry-related domain. Our approach addresses any combination of local symmetries, thus applying in particular to acoustic, optical and matter waves. Nonvanishing values of the invariant currents provide a systematic ...
Invariants of Broken Discrete Symmetries
Kalozoumis, P. A.; Morfonios, C.; Diakonos, F. K.; Schmelcher, P.
2014-08-01
The parity and Bloch theorems are generalized to the case of broken global symmetry. Local inversion or translation symmetries in one dimension are shown to yield invariant currents that characterize wave propagation. These currents map the wave function from an arbitrary spatial domain to any symmetry-related domain. Our approach addresses any combination of local symmetries, thus applying, in particular, to acoustic, optical, and matter waves. Nonvanishing values of the invariant currents provide a systematic pathway to the breaking of discrete global symmetries.
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).
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...
Neutrino masses and spontaneously broken flavor symmetries
Energy Technology Data Exchange (ETDEWEB)
Staudt, Christian
2014-06-16
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){sub R} symmetry which explains the fermion mass hierarchies and, when amended with additional singlet fields, ameliorates the fine-tuning problem.
Ratchet device with broken friction symmetry
DEFF Research Database (Denmark)
Norden, Bengt; Zolotaryuk, Yaroslav; Christiansen, Peter Leth
2002-01-01
An experimental setup (gadget) has been made for demonstration of a ratchet mechanism induced by broken symmetry of a dependence of dry friction on external forcing. This gadget converts longitudinal oscillating or fluctuating motion into a unidirectional rotation, the direction of which is in ac......An experimental setup (gadget) has been made for demonstration of a ratchet mechanism induced by broken symmetry of a dependence of dry friction on external forcing. This gadget converts longitudinal oscillating or fluctuating motion into a unidirectional rotation, the direction of which...
Ratchet due to broken friction symmetry
DEFF Research Database (Denmark)
Norden, Bengt; Zolotaryuk, Yaroslav; Christiansen, Peter Leth
2002-01-01
A ratchet mechanism that occurs due to asymmetric dependence of the friction of a moving system on its velocity or a driving force is reported. For this kind of ratchet, instead of a particle moving in a periodic potential, the dynamics of which have broken space-time symmetry, the system must...
Rotating optical microcavities with broken chiral symmetry
Sarma, Raktim; Wiersig, Jan; Cao, Hui
2014-01-01
We demonstrate in open microcavities with broken chiral symmetry, quasi-degenerate pairs of co-propagating modes in a non-rotating cavity evolve to counter-propagating modes with rotation. The emission patterns change dramatically by rotation, due to distinct output directions of CW and CCW waves. By tuning the degree of spatial chirality, we maximize the sensitivity of microcavity emission to rotation. The rotation-induced change of emission is orders of magnitude larger than the Sagnac effect, pointing to a promising direction for ultrasmall optical gyroscopes.
Parity-time symmetry broken by point-group symmetry
Energy Technology Data Exchange (ETDEWEB)
Fernández, Francisco M., E-mail: fernande@quimica.unlp.edu.ar; Garcia, Javier [INIFTA (UNLP, CCT La Plata-CONICET), División Química Teórica, Blvd. 113 S/N, Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina)
2014-04-15
We discuss a parity-time (PT) symmetric Hamiltonian with complex eigenvalues. It is based on the dimensionless Schrödinger equation for a particle in a square box with the PT-symmetric potential V(x, y) = iaxy. Perturbation theory clearly shows that some of the eigenvalues are complex for sufficiently small values of |a|. Point-group symmetry proves useful to guess if some of the eigenvalues may already be complex for all values of the coupling constant. We confirm those conclusions by means of an accurate numerical calculation based on the diagonalization method. On the other hand, the Schrödinger equation with the potential V(x, y) = iaxy{sup 2} exhibits real eigenvalues for sufficiently small values of |a|. Point group symmetry suggests that PT-symmetry may be broken in the former case and unbroken in the latter one.
Nonreciprocal Multiferroic Superlattices with Broken Parity Symmetry
Tang, Zhenghua; Zhang, Weiyi
Multiferroic materials are characterized by the coexistence of ferroelectric and ferromagnetic (or antiferromagnetic) orders, the coupling to lattice vibration can be invoked either through piezoelectric or piezomagnetic effects. In this paper, the polaritonic band structures of multiferroic superlattices composed of oppositely polarized domains are investigated using the generalized transfer matrix method. For the primitive cell with broken parity symmetry, the polaritonic band structure is asymmetrical with respect to the forward and backward propagation directions (nonreciprocality). In particular, the band extreme points move away from the Brillouin zone center. This asymmetry in band-gap positions and widths can be used to design compact one-way optical isolators, while the extremely slow light velocities near the asymmetrical upper edges of lower bands includes the essential ingredients for designing slow light devices.
Neutrino Mixing:. from the Broken μ-τ Symmetry to the Broken Friedberg-Lee Symmetry
Xing, Zhi-Zhong
I argue that the observed flavor structures of leptons and quarks might imply the existence of certain flavor symmetries. The latter should be a good starting point to build realistic models towards deeper understanding of the fermion mass spectra and flavor mixing patterns. The μ-τ permutation symmetry serves for such an example to interpret the almost maximal atmospheric neutrino mixing angle (θ23 ~ 45°) and the strongly suppressed CHOOZ neutrino mixing angle (θ13 Friedberg-Lee symmetry, for the effective Majorana neutrino mass operator. Luo and I have shown that this symmetry can be broken in an oblique way, such that the lightest neutrino remains massless but an experimentally-favored neutrino mixing pattern is achievable. We get a novel prediction for θ13 in the CP-conserving case: sinθ13 = tanθ12|(1 - tanθ23)/(1 + tanθ23)|. Our scenario can simply be generalized to accommodate CP violation and be combined with the seesaw mechanism. Finally I stress the importance of probing possible effects of μ-τ symmetry breaking either in terrestrial neutrino oscillation experiments or with ultrahigh-energy cosmic neutrino telescopes.
Neutrino Mixing: from the Broken \\mu-\\tau Symmetry to the Broken Friedberg-Lee Symmetry
Xing, Z
2007-01-01
I argue that the observed flavor structures of leptons and quarks might imply the existence of certain flavor symmetries. The latter should be a good starting point to build realistic models towards deeper understanding of the fermion mass spectra and flavor mixing patterns. The \\mu-\\tau permutation symmetry serves for such an example to interpret the almost maximal atmospheric neutrino mixing angle (\\theta_23 \\sim 45^\\circ) and the strongly suppressed CHOOZ neutrino mixing angle (\\theta_13 < 10^\\circ). In this talk I like to highlight a new kind of flavor symmetry, the Friedberg-Lee symmetry, for the effective Majorana neutrino mass operator. Luo and I have shown that this symmetry can be broken in an oblique way, such that the lightest neutrino remains massless but an experimentally-favored neutrino mixing pattern is achievable. We get a novel prediction for \\theta_13 in the CP-conserving case: \\sin\\theta_13 = \\tan\\theta_12 |(1- \\tan\\theta_23)/ (1+ \\tan\\theta_{23})|. Our scenario can simply be generalize...
The Small Step toward Asymmetry: Aesthetic Judgment of Broken Symmetries
Directory of Open Access Journals (Sweden)
Andreas Gartus
2013-08-01
Full Text Available Symmetry and complexity both affect the aesthetic judgment of abstract patterns. However, although beauty tends to be associated with symmetry, there are indications that small asymmetries can also be beautiful. We investigated the influence of small deviations from symmetry on people's aesthetic liking for abstract patterns. Breaking symmetry not only decreased patterns' symmetry but also increased their complexity. While an increase of complexity normally results in a higher liking, we found that even a small decrease of symmetry has a strong effect, such that patterns with slightly broken symmetries were significantly less liked than fully symmetric ones.
Strongly broken Peccei-Quinn symmetry in the early Universe
Energy Technology Data Exchange (ETDEWEB)
Takahashi, Fuminobu [Department of Physics, Tohoku University,Sendai, Miyagi 980-8578 (Japan); Kavli IPMU (WPI), TODIAS, The University of Tokyo,Kashiwa, Chiba 277-8583 (Japan); Yamada, Masaki [Kavli IPMU (WPI), TODIAS, The University of Tokyo,Kashiwa, Chiba 277-8583 (Japan); Institute for Cosmic Ray Research, ICRR, The University of Tokyo,Kashiwa, Chiba 277-8582 (Japan)
2015-10-06
We consider QCD axion models where the Peccei-Quinn symmetry is badly broken by a larger amount in the past than in the present, in order to avoid the axion isocurvature problem. Specifically we study supersymmetric axion models where the Peccei-Quinn symmetry is dynamically broken by either hidden gauge interactions or the SU(3){sub c} strong interactions whose dynamical scales are temporarily enhanced by the dynamics of flat directions. The former scenario predicts a large amount of self-interacting dark radiation as the hidden gauge symmetry is weakly coupled in the present Universe. We also show that the observed amount of baryon asymmetry can be generated by the QCD axion dynamics via spontaneous baryogenesis. We briefly comment on the case in which the PQ symmetry is broken by a non-minimal coupling to gravity.
Misunderstanding that the Effective Action is Convex under Broken Symmetry
Asanuma, Nobu-Hiko
2016-01-01
The widespread belief that the effective action is convex and has a flat bottom under broken global symmetry is shown to be wrong. We show spontaneous symmetry breaking necessarily accompanies non-convexity in the effective action for quantum field theory, or in the free energy for statistical mechanics, and clarify the magnitude of non-convexity. For quantum field theory, it is also explicitly proved that translational invariance breaks spontaneously when the system is in the non-convex region, and that different vacua of spontaneously broken symmetry cannot be superposed. As applications of non-convexity, we study the first-order phase transition which happens at the zero field limit of spontaneously broken symmetry, and we propose a simple model of phase coexistence which obeys the Born rule.
Broken particle-hole symmetry in critical fluids
Goldstein, Raymond E.; Parola, Alberto
1988-06-01
The quantitative validity of asymptotic particle-hole symmetry in a fluid at its liquid-vapor critical point is determined by means of the exact mapping of the fluid Hamiltonian onto that of an effective Landau-Ginzburg-Wilson model studied first by Hubbard and Schofield. A particular three-particle correlation of a reference fluid is identified as that which controls the breaking of liquid-vapor symmetry, as manifested in a linear mixing of the pure Ising-like scaling fields and a singularity in the coexistence curve diameter. The inherent smallness of the mixing coefficient in a pair-potential fluid is shown to reflect the weak density dependence of the second moment of the two-particle direct correlation function of the reference system. It is further demonstrated that three-body interactions of the Axilrod-Teller-type enhance the broken particle-hole symmetry found in a purely pairwise-additive Hamiltonian, and detailed calculations give diameter anomaly amplitudes which vary linearly with the fluid polarizability, in quantitative agreement with recent experiments.
Squeezing lepton pairs out of broken symmetries
Dutt-Mazumder, A K; Majumder, A; Teodorescu, O
2002-01-01
We discuss two possible signatures of symmetry breaking that can appear in dilepton spectra, as measured in relativistic heavy ion collisions. The first involves scalar-vector meson mixing and is related to the breaking of Lorentz symmetry by a hot medium. The second is related to the breaking of Furry's theorem by a charged quark-gluon plasma. Those signals will be accessible to upcoming measurements to be performed at the GSI, RHIC, and the LHC.
Spontaneously broken Lorentz symmetry and gravity
Jacobson, T; Jacobson, Ted; Mattingly, David
2000-01-01
We study a generally covariant model in which local Lorentz invariance is broken "spontaneously" by a dynamical unit timelike vector field $u^a$---the "aether". Such a model makes it possible to study the gravitational and cosmological consequences of preferred frame effects, such as ``variable speed of light" or high frequency dispersion, while preserving a generally covariant metric theory of gravity. In this paper we restrict attention to an action for an effective theory of the aether which involves only the antisymmetrized derivative $\
Elastoconductivity as a probe of broken mirror symmetries
Energy Technology Data Exchange (ETDEWEB)
Hlobil, Patrik; Maharaj, Akash V.; Hosur, Pavan; Shapiro, M. C.; Fisher, I. R.; Raghu, S.
2015-07-27
We propose the possible detection of broken mirror symmetries in correlated two-dimensional materials by elastotransport measurements. Using linear response theory we calculate the“shear conductivity” Γ x x , x y , defined as the linear change of the longitudinal conductivity σ x x due to a shear strain ε x y . This quantity can only be nonvanishing when in-plane mirror symmetries are broken and we discuss how candidate states in the cuprate pseudogap regime (e.g., various loop current or charge orders) may exhibit a finite shear conductivity. We also provide a realistic experimental protocol for detecting such a response.
Non-gaussianity from broken symmetries
Energy Technology Data Exchange (ETDEWEB)
Kolb, Edward W.; /Fermilab /Chicago U., Astron. Astrophys. Ctr. /Chicago U., EFI; Riotto, Antonio; /CERN; Vallinotto, Alberto; /Chicago U. /Fermilab
2005-11-01
Recently we studied inflation models in which the inflation potential is characterized by an underlying approximate global symmetry. In the first work we pointed out that in such a model curvature perturbations are generated after the end of the slow-roll phase of inflation. In this work we develop further the observational implications of the model and compute the degree of non-Gaussianity predicted in the scenario. We find that the corresponding nonlinearity parameter, F{sub NL}, can be as large as 10{sup 2}.
Field, J H
2016-01-01
Space-time intervals corresponding to different events on the worldline of any ponderable object (for example a clock) are time-like. In consequence, in the analysis of any space-time experiment involving clocks only the region for $c\\Delta t \\ge 0$ between the line $\\Delta x = 0$ and the light cone projection $c\\Delta t = \\Delta x$ of the $c\\Delta t$ versus $\\Delta x$ Minkowski plot is physically relevant. This breaks the manifest space-time symmetry of the plot. A further consequence is the unphysical nature of the `relativity of simultaneity' and `length contraction' effects of conventional special relativity theory. The only modification of space-time transformation laws in passing from Galilean to special relativity is then the replacement of universal Newtonian time by a universal (position independent) time dilation effect for moving clocks.
Quantum restoration of broken symmetry in onedimensional loop space
Indian Academy of Sciences (India)
Pinaki Patra; Tanmay Mandal; Jyoti Prasad Saha
2014-06-01
For one-dimensional loop space, a nonlinear nonlocal transformation of fields is given to make the action of the self-interacting quantum field to the free one. A specific type of classically broken symmetry is restored in quantum theory. One-dimensional sine-Gordon system and sech interactions are treated as the explicit examples.
Bags in relativistic quantum field theory with spontaneously broken symmetry
Energy Technology Data Exchange (ETDEWEB)
Wadati, M.; Matsumoto, H.; Umezawa, H.
1978-08-15
Presented is a microscopic derivation of bags from a relativistic quantum theory with spontaneously broken symmetry. The static energy of a bag whose singularity is the surface of a sphere coincides with the volume tension in the MIT bag theory. A similarity between the bags and the point defects in crystals is pointed out.
Consistency condition for inflation from (broken) conformal symmetry
Energy Technology Data Exchange (ETDEWEB)
Schalm, Koenraad; Aalst, Ted van der [Instituut-Lorentz for Theoretical Physics, Universiteit Leiden, Niels Bohrweg 2, Leiden (Netherlands); Shiu, Gary, E-mail: kschalm@lorentz.leidenuniv.nl, E-mail: shiu@physics.wisc.edu, E-mail: vdaalst@lorentz.leidenuniv.nl [Department of Physics, University of Wisconsin-Madison, Madison, WI 53706 (United States)
2013-03-01
We investigate the symmetry constraints on the bispectrum, i.e. the three-point correlation function of primordial density fluctuations, in slow-roll inflation. It follows from the defining property of slow-roll inflation that primordial correlation functions inherit most of their structure from weakly broken de Sitter symmetries. Using holographic techniques borrowed from the AdS/CFT correspondence, the symmetry constraints on the bispectrum can be mapped to a set of stress-tensor Ward identities in a weakly broken 2+1-dimensional Euclidean CFT. We construct the consistency condition from these Ward identities using conformal perturbation theory. This requires a second order Ward identity and the use of the evolution equation. Our result also illustrates a subtle difference between conformal perturbation theory and the slow-roll expansion.
Adiabatic approximation for the Rabi model with broken inversion symmetry
Shen, Li-Tuo; Yang, Zhen-Biao; Wu, Huai-Zhi
2017-01-01
We study the properties and behavior of the Rabi model with broken inversion symmetry. Using an adiabatic approximation approach, we explore the high-frequency qubit and oscillator regimes, and obtain analytical solutions for the qubit-oscillator system. We demonstrate that, due to broken inversion symmetry, the positions of two potentials and zero-point energies in the oscillators become asymmetric and have a quadratic dependence on the mean dipole moments within the high-frequency oscillator regime. Furthermore, we find that there is a critical point above which the qubit-oscillator system becomes unstable, and the position of this critical point has a quadratic dependence on the mean dipole moments within the high-frequency qubit regime. Finally, we verify this critical point based on the method of semiclassical approximation.
Massive Kaluza-Klein theories and their spontaneously broken symmetries
Energy Technology Data Exchange (ETDEWEB)
Hohm, O.
2006-07-15
In this thesis we investigate the effective actions for massive Kaluza-Klein states, focusing on the massive modes of spin-3/2 and spin-2 fields. To this end we determine the spontaneously broken gauge symmetries associated to these 'higher-spin' states and construct the unbroken phase of the Kaluza-Klein theory. We show that for the particular background AdS{sub 3} x S{sup 3} x S{sup 3} a consistent coupling of the first massive spin-3/2 multiplet requires an enhancement of local supersymmetry, which in turn will be partially broken in the Kaluza-Klein vacuum. The corresponding action is constructed as a gauged maximal supergravity in D=3. Subsequently, the symmetries underlying an infinite tower of massive spin-2 states are analyzed in case of a Kaluza-Klein compactification of four-dimensional gravity to D=3. It is shown that the resulting gravity-spin-2 theory is given by a Chern-Simons action of an affine algebra and also allows a geometrical interpretation in terms of 'algebra-valued' differential geometry. The global symmetry group is determined, which contains an affine extension of the Ehlers group. We show that the broken phase can in turn be constructed via gauging a certain subgroup of the global symmetry group. Finally, deformations of the Kaluza-Klein theory on AdS{sub 3} x S{sup 3} x S{sup 3} and the corresponding symmetry breakings are analyzed as possible applications for the AdS/CFT correspondence. (Orig.)
Excitation of dark plasmonic modes in symmetry broken terahertz metamaterials.
Chowdhury, Dibakar Roy; Su, Xiaofang; Zeng, Yong; Chen, Xiaoshuang; Taylor, Antoinette J; Azad, Abul
2014-08-11
Plasmonic structures with high symmetry, such as double-identical gap split ring resonators, possess dark eigenmodes. These dark eigenmodes are dominated by magnetic dipole and/or higher-order multi-poles such as electric quadrapoles. Consequently these dark modes interact very weakly with the surrounding environment, and can have very high quality factors (Q). In this work, we have studied, experimentally as well as theoretically, these dark eigenmodes in terahertz metamaterials. Theoretical investigations with the help of classical perturbation theory clearly indicate the existence of these dark modes in symmetric plasmonic metamaterials. However, these dark modes can be excited experimentally by breaking the symmetry within the constituting metamaterial resonators cell, resulting in high quality factor resonance mode. The symmetry broken metamaterials with such high quality factor can pave the way in realizing high sensitivity sensors, in addition to other applications.
Anomalous dimensions in CFT with weakly broken higher spin symmetry
Giombi, Simone; Kirilin, Vladimir
2016-11-01
In a conformal field theory with weakly broken higher spin symmetry, the leading order anomalous dimensions of the broken currents can be efficiently determined from the structure of the classical non-conservation equations. We apply this method to the explicit example of O( N) invariant scalar field theories in various dimensions, including the large N critical O( N) model in general d, the Wilson-Fisher fixed point in d = 4 - ɛ, cubic scalar models in d = 6 - ɛ and the nonlinear sigma model in d = 2 + ɛ. Using information from the d = 4 - ɛ and d = 2 + ɛ expansions, we obtain some estimates for the dimensions of the higher spin operators in the critical 3d O( N) models for a few low values of N and spin.
Symmetry Broken Exact Coherent Structures in Plane Couette Flow
Gopalaswamy, Varchas; Borrero-Echeverry, Daniel
2015-11-01
Invariant solutions of the fully resolved Navier-Stokes equation, known as exact coherent structures (ECS) are an exciting and potentially revolutionary method for understanding turbulent dynamics. The geometry of plane Couette flow leads to the existence of ECS with a high degree of symmetry. However, turbulent flows do not display a high degree of symmetry, so it is unclear whether these symmetric ECS can truly capture the turbulent dynamics. We report the discovery of four new periodic orbits - P85 and P60 which are fully symmetric, and P32 and P8, which have partially broken symmetry. Projections of these periodic orbits in the dissipation-energy input plane reveal that P32, P60 and P85 lie in the turbulent region of the state space, whereas P8 lies very far away from this region. Parametric continuation in the spanwise periodic cell length Lz suggests that P8 undergoes two bifurcations, which are verified by analysis of various properties of P8 in the dissipation-energy input plane, and by observations of changes in the stability of eigenvectors that are consistent with bifurcations.
Phases of holographic superconductors with broken translational symmetry
Baggioli, Matteo
2015-01-01
We consider holographic superconductors in a broad class of massive gravity backgrounds. These theories provide a holographic description of a superconductor with broken translational symmetry. Such models exhibit a rich phase structure: depending on the values of the temperature and the doping the boundary system can be in superconducting, normal metallic or normal pseudo-insulating phases. Furthermore the system supports interesting collective excitations of the charge carriers, which appears in the normal phase, persists in the superconducting phase, but eventually gets destroyed by the superconducting condensate. We also show the possibility of building a phase diagram of a system with the superconducting phase occupying a dome-shaped region, therefore resembling more of a real-world doped high-Tc superconductor.
Gauge-Higgs unification with broken flavour symmetry
Energy Technology Data Exchange (ETDEWEB)
Olschewsky, M.
2007-05-15
We study a five-dimensional Gauge-Higgs unification model on the orbifold S{sup 1}/Z{sub 2} based on the extended standard model (SM) gauge group SU(2){sub L} x U(1){sub Y} x SO(3){sub F}. The group SO(3){sub F} is treated as a chiral gauged flavour symmetry. Electroweak-, flavour- and Higgs interactions are unified in one single gauge group SU(7). The unified gauge group SU(7) is broken down to SU(2){sub L} x U(1){sub Y} x SO(3){sub F} by orbifolding and imposing Dirichlet and Neumann boundary conditions. The compactification scale of the theory is O(1) TeV. Furthermore, the orbifold S{sup 1}/Z{sub 2} is put on a lattice. This setting gives a well-defined staring point for renormalisation group (RG) transformations. As a result of the RG-flow, the bulk is integrated out and the extra dimension will consist of only two points: the orbifold fixed points. The model obtained this way is called an effective bilayered transverse lattice model. Parallel transporters (PT) in the extra dimension become nonunitary as a result of the blockspin transformations. In addition, a Higgs potential V({phi}) emerges naturally. The PTs can be written as a product e{sup A{sub y}}e{sup {eta}}e{sup A{sub y}} of unitary factors e{sup A{sub y}} and a selfadjoint factor e{sup {eta}}. The reduction 48 {yields} 35 + 6 + anti 6 + 1 of the adjoint representation of SU(7) with respect to SU(6) contains SU(2){sub L} x U(1){sub Y} x SO(3){sub F} leads to three SU(2){sub L} Higgs doublets: one for the first, one for the second and one for the third generation. Their zero modes serve as a substitute for the SM Higgs. When the extended SM gauge group SU(2){sub L} x U(1){sub Y} x SO(3){sub F} is spontaneously broken down to U(1){sub em}, an exponential gauge boson mass splitting occurs naturally. At a first step SU(2){sub L} x U(1){sub Y} x SO(3){sub F} is broken to SU(2){sub L} x U(1){sub Y} by VEVs for the selfadjoint factor e{sup {eta}}. This breaking leads to masses of flavour changing SO(3){sub F
Broken Time Translation Symmetry as a Model for Quantum State Reduction
Directory of Open Access Journals (Sweden)
Jasper van Wezel
2010-04-01
Full Text Available The symmetries that govern the laws of nature can be spontaneously broken, enabling the occurrence of ordered states. Crystals arise from the breaking of translation symmetry, magnets from broken spin rotation symmetry and massive particles break a phase rotation symmetry. Time translation symmetry can be spontaneously broken in exactly the same way. The order associated with this form of spontaneous symmetry breaking is characterised by the emergence of quantum state reduction: systems which spontaneously break time translation symmetry act as ideal measurement machines. In this review the breaking of time translation symmetry is first compared to that of other symmetries such as spatial translations and rotations. It is then discussed how broken time translation symmetry gives rise to the process of quantum state reduction and how it generates a pointer basis, Born’s rule, etc. After a comparison between this model and alternative approaches to the problem of quantum state reduction, the experimental implications and possible tests of broken time translation symmetry in realistic experimental settings are discussed.
Cosmological Reflection of Particle Symmetry
Directory of Open Access Journals (Sweden)
Maxim Khlopov
2016-08-01
Full Text Available The standard model involves particle symmetry and the mechanism of its breaking. Modern cosmology is based on inflationary models with baryosynthesis and dark matter/energy, which involves physics beyond the standard model. Studies of the physical basis of modern cosmology combine direct searches for new physics at accelerators with its indirect non-accelerator probes, in which cosmological consequences of particle models play an important role. The cosmological reflection of particle symmetry and the mechanisms of its breaking are the subject of the present review.
Reflection losses from imperfectly broken fiber ends.
Marcuse, D
1975-12-01
This paper presents an approximate theory for determining the reflection losses in multimode fibers that terminate in end surfaces that are not strictly perpendicular to the fiber axis. This theory is also applicable to tilts and covers step index as well as parabolic index fibers. The cross section of the step index fiber is assumed to have square geometry. This assumption simplifies the theory and is not expected to influ-ence the obtained results.
Cosmological Reflection of Particle Symmetry
Maxim Khlopov
2016-01-01
The standard model involves particle symmetry and the mechanism of its breaking. Modern cosmology is based on inflationary models with baryosynthesis and dark matter/energy, which involves physics beyond the standard model. Studies of the physical basis of modern cosmology combine direct searches for new physics at accelerators with its indirect non-accelerator probes, in which cosmological consequences of particle models play an important role. The cosmological reflection of particle symmetr...
Under The Dome: Doped holographic superconductors with broken translational symmetry
Baggioli, Matteo
2015-01-01
We comment on a simple way to accommodate translational symmetry breaking into the recently proposed holographic model which features a superconducting dome-shaped region on the temperature-doping phase diagram.
Broken versus Non-Broken Time Reversal Symmetry: Irreversibility and Response
Directory of Open Access Journals (Sweden)
Sara Dal Cengio
2016-07-01
Full Text Available We review some approaches to macroscopic irreversibility from reversible microscopic dynamics, introducing the contribution of time dependent perturbations within the framework of recent developments in non-equilibrium statistical physics. We show that situations commonly assumed to violate the time reversal symmetry (presence of magnetic fields, rotating reference frames, and some time dependent perturbations in reality do not violate this symmetry, and can be treated with standard theories and within standard experimental protocols.
Hadrons and broken symmetries with WASA-at-COSY
Indian Academy of Sciences (India)
S Schadmand; Wasa-at-Cosy
2010-08-01
The WASA Detector Facility is an internal experiment at the cooler synchrotron (COSY) in Jülich, Germany. The COSY accelerator provides proton and deuteron beams with momenta up to 3.7 GeV/c giving access to hadron physics including the strange quark sector. The physics program with the WASA detector involves hadron dynamics and hadron structure. Key experiments address fundamental symmetries and symmetry violations via the study of rare and not-so-rare meson decays. From the very first production run, results on the Dalitz plot slope parameter in the isospin violating → 30 decay have been obtained. The 30 final state is also used to study meson production mechanisms. Investigations of other decay modes of the -meson address , , and symmetries and combinations. Higher orders in chiral perturbation theory are probed with the → 0 decay. The status and plans for studying hadron structure with Dalitz decays of mesons are presented.
Z2 antiferromagnetic topological insulators with broken C4 symmetry
Bègue, Frédéric; Pujol, Pierre; Ramazashvili, Revaz
2017-04-01
A two-dimensional topological insulator may arise in a centrosymmetric commensurate Néel antiferromagnet (AF), where staggered magnetization breaks both the elementary translation and time reversal, but retains their product as a symmetry. Fang et al. [6] proposed an expression for a Z2 topological invariant to characterize such systems. Here, we show that this expression does not allow to detect all the existing phases if a certain lattice symmetry is lacking. We implement numerical techniques to diagnose topological phases of a toy Hamiltonian, and verify our results by computing the Chern numbers of degenerate bands, and also by explicitly constructing the edge states, thus illustrating the efficiency of the method.
Baskaran, G.
1989-01-01
Using a nonmean-field approach the triangular-lattice S = 1/2 Heisenberg antiferromagnet with nearest- and next-nearest-neighbor couplings is shown undergo an Ising-type phase transition into a chiral-symmetry-broken phase (Kalmeyer-Laughlin-like state) at small T. Removal of next-nearest-neighbor coupling introduces a local Z2 symmetry, thereby suppressing any finite-T chiral order.
Phenomenology of the standard model under conditions of spontaneously broken mirror symmetry
Energy Technology Data Exchange (ETDEWEB)
Dyatlov, I. T., E-mail: dyatlov@thd.pnpi.spb.ru [National Research Center Kurchatov Institute, Petersburg Nuclear Physics Institute (Russian Federation)
2017-03-15
Spontaneously broken mirror symmetry is able to reproduce observed qualitative properties of weak mixing for quark and leptons. Under conditions of broken mirror symmetry, the phenomenology of leptons—that is, small neutrino masses and a mixing character other than that in the case of quarks—requires the Dirac character of the neutrinos and the existence of processes violating the total lepton number. Such processes involve heavy mirror neutrinos; that is, they proceed at very high energies. Here, CP violation implies that a P-even mirror-symmetric Lagrangian must simultaneously be T-odd and, according to the CPT theorem, C-odd. All these properties create preconditions for the occurrence of leptogenesis, which is a mechanism of the emergence of the baryon–lepton asymmetry of the universe in models featuring broken mirror symmetry.
Dynamics of Localized Structures in Systems with Broken Parity Symmetry
Javaloyes, J; Marconi, M; Giudici, M
2016-01-01
A great variety of nonlinear dissipative systems are known to host structures having a correlation range much shorter than the size of the system. The dynamics of these Localized Structures (LSs) have been investigated so far in situations featuring parity symmetry. In this letter we extend this analysis to systems lacking of this property. We show that the LS drifting speed in a parameter varying landscape is not simply proportional to the parameter gradient, as found in parity preserving situations. The symmetry breaking implies a new contribution to the velocity field which is a function of the parameter value, thus leading to a new paradigm for LSs manipulation. We illustrate this general concept by studying the trajectories of the LSs found in a passively mode-locked laser operated in the localization regime. Moreover, the lack of parity affects significantly LSs interactions which are governed by asymmetrical repulsive forces.
Observation and elimination of broken symmetry in L1{sub 0} FePt nanostructures
Energy Technology Data Exchange (ETDEWEB)
Quarterman, P.; Wang, Hao; Qiu, Jiao-Ming; Ma, Bin; Liu, Xiaoqi; Wang, Jian-Ping, E-mail: jpwang@umn.edu [Department of Electrical and Computer Engineering and the Center for Micromagnetics and Information Technologies (MINT), University of Minnesota, Minnesota 55455 (United States); Guo, Honghua [Department of Optical Science and Engineering, Fudan University, Shanghai (China)
2015-12-07
An unexplained surface anisotropy effect was observed and confirmed in the magnetization reversal process of both L1{sub 0} phase FePt nanoparticles with octahedral shape and (001) textured L1{sub 0} FePt thin films with island nanostructures. We suggest that the nature of the observed surface effect is caused by broken symmetry on the FePt surface, which results in weakened exchange coupling for surface atoms. Furthermore, we propose, and experimentally demonstrate, a method to repair the broken symmetry by capping the FePt islands with a Pt layer, which could prove invaluable in understanding fundamental limitations of magnetic nanostructures.
The diversity of type Ia supernovae from broken symmetries.
Kasen, D; Röpke, F K; Woosley, S E
2009-08-13
Type Ia supernovae result when carbon-oxygen white dwarfs in binary systems accrete mass from companion stars, reach a critical mass and explode. The near uniformity of their light curves makes these supernovae good 'standard candles' for measuring cosmic expansion, but a correction must be applied to account for the fact that the brighter ones have broader light curves. One-dimensional modelling, with a certain choice of parameters, can reproduce this general trend in the width-luminosity relation; but the processes of ignition and detonation have recently been shown to be intrinsically asymmetric, so parameterization must have its limits. Here we report multi-dimensional modelling of the explosion physics and radiative transfer, which reveals that the breaking of spherical symmetry is a critical factor in determining both the width-luminosity relation and the observed scatter about it. The deviation from spherical symmetry can also explain the finite polarization detected in the light from some supernovae. The slope and normalization of the width-luminosity relation has a weak dependence on certain properties of the white dwarf progenitor, in particular the trace abundances of elements other than carbon and oxygen. Failing to correct for this effect could lead to systematic overestimates of up to 2 per cent in the distance to remote supernovae.
Phenomenology of Standard Model in spontaneously broken mirror symmetry
Dyatlov, Igor T
2016-01-01
Violated mirror symmetry (MS) is capable of reproducing observed qualitative properties of weak mixing for quarks and leptons. In violated MS, lepton phenomenology, that is, small neutrino masses and mixing properties different from those of quarks, requires the Dirac nature of neutrinos and existence of processes that change the total lepton number. Such processes involve heavy mirror neutrinos, and therefore occur at very high energies. CP non-conservation would mean here that the parity conserving MS Lagrangian must be non-invariant to both time reversal T and (according to the CPT theorem) the charge conjugation C. All these properties create appropriate conditions for leptogenesis, a mechanism for generating baryon-lepton asymmetry of the Universe in violated MS models.
Broken flavor symmetries in high energy particle phenomenology
Energy Technology Data Exchange (ETDEWEB)
Antaramian, A.
1995-02-22
Over the past couple of decades, the Standard Model of high energy particle physics has clearly established itself as an invaluable tool in the analysis of high energy particle phenomenon. However, from a field theorists point of view, there are many dissatisfying aspects to the model. One of these, is the large number of free parameters in the theory arising from the Yukawa couplings of the Higgs doublet. In this thesis, we examine various issues relating to the Yukawa coupeng structure of high energy particle field theories. We begin by examining extensions to the Standard Model of particle physics which contain additional scalar fields. By appealing to the flavor structure observed in the fermion mass and Kobayashi-Maskawa matrices, we propose a reasonable phenomenological parameterization of the new Yukawa couplings based on the concept of approximate flavor symmetries. It is shown that such a parameterization eliminates the need for discrete symmetries which limit the allowed couplings of the new scalars. New scalar particles which can mediate exotic flavor changing reactions can have masses as low as the weak scale. Next, we turn to the issue of neutrino mass matrices, where we examine a particular texture which leads to matter independent neutrino oscillation results for solar neutrinos. We, then, examine the basis for extremely strict limits placed on flavor changing interactions which also break lepton- and/or baryon-number. These limits are derived from cosmological considerations. Finally, we embark on an extended analysis of proton decay in supersymmetric SO(10) grand unified theories. In such theories, the dominant decay diagrams involve the Yukawa couplings of a heavy triplet superfield. We argue that past calculations of proton decay which were based on the minimal supersymmetric SU(5) model require reexamination because the Yukawa couplings of that theory are known to be wrong.
Broken symmetries at high temperatures and the problem of baryon excess of the universe
Mohapatra, Rabindra N
1979-01-01
We discuss a class of gauge theories, where spontan- eously broken symmetries, instead of being restored, persist as the temperature is increased. Applying these ideas to the specific case of the soft CP- viola tion in grand unified theories, we discuss a mechanism to generate the baryon to entropy ratio of the universe.
Quench of a symmetry-broken ground state
Giampaolo, S. M.; Zonzo, G.
2017-01-01
We analyze the problem of how different ground states associated with the same set of Hamiltonian parameters evolve after a sudden quench. To realize our analysis we define a quantitative approach to the local distinguishability between different ground states of a magnetically ordered phase in terms of the trace distance between the reduced density matrices obtained by projecting two ground states in the same subset. Before the quench, regardless of the particular choice of subset, any system in a magnetically ordered phase is characterized by ground states that are locally distinguishable. On the other hand, after the quench, the maximum distinguishability shows an exponential decay in time. Hence, in the limit of very long times, all the information about the particular initial ground state is lost even if the systems are integrable. We prove our claims in the framework of the magnetically ordered phases that characterize both the X Y and the N -cluster Ising models. The fact that we find similar behavior in models within different classes of symmetry makes us confident about the generality of our results.
Surface Broken Symmetry on Orthorhombic Double-layer Sr3(Ru1-xMnx)2 O7
Chen, Chen; Nascimento, V. B.; Diao, Zhenyu; Zhang, Jiandi; Jin, Rongying; Plummer, E. W.
The surface of double-layered ruthenate Sr3Ru2O7 exhibits octahedra tilt distortion and an enhanced rotational distortion caused by the broken symmetry. Previous LEED IV calculation reveals that the tilt angle is (2.5+/-1.7)°at 80 K (B. Hu et. al., Physical Review B 81, 184104 (2010). A glideline symmetry and a mirror symmetry along this direction are both broken. Results from LEED IV simulations show that both broken symmetries originate from the emergence of surface tilt. The degree of broken symmetry is more sensitive to the tilt angle, thus producing a smaller error than from conventional LEED IV calculation. When Mn doping is induced into the compound, the tilt is removed and the symmetry of the LEED pattern returns to what is expected for rotation, two glide planes and four-fold symmetry. Supported by NSF DMR-1002622.
Broken SU(3) x SU(3) x SU(3) x SU(3) Symmetry
Freund, P. G. O.; Nambu, Y.
1964-10-01
We argue that the "Eight-fold Way" version of the SU(3) symmetry should be extended to a product of up to four separate and badly broken SU(3) groups, including the gamma{sub 5} type SU(3) symmetry. A hierarchy of subgroups (or subalgebras) are considered within this framework, and two candidates are found to be interesting in view of experimental evidence. Main features of the theory are: 1) the baryons belong to a nonet; 2) there is an octet of axial vector gauge mesons in addition to one or two octets of vector mesons; 3) pseudoscalar and scalar mesons exist as "incomplete" multiplets arising from spontaneous breakdown of symmetry.
Energy Technology Data Exchange (ETDEWEB)
Tareyeva, E.E. [Institute for High Pressure Physics, Russian Academy of Sciences, 142190 Troitsk (Russian Federation); Schelkacheva, T.I., E-mail: tanschelk@gmail.com [Institute for High Pressure Physics, Russian Academy of Sciences, 142190 Troitsk (Russian Federation); Chtchelkatchev, N.M. [Institute for High Pressure Physics, Russian Academy of Sciences, 142190 Troitsk (Russian Federation); L.D. Landau Institute for Theoretical Physics, Russian Academy of Sciences, 117940 Moscow (Russian Federation); Department of Theoretical Physics, Moscow Institute of Physics and Technology, 141700 Moscow (Russian Federation)
2013-02-15
We investigate near the point of glass transition the expansion of the free energy corresponding to the generalized Sherrington–Kirkpatrick model with arbitrary diagonal operators U{sup -hat} standing instead of Ising spins. We focus on the case when U{sup -hat} is an operator with broken reflection symmetry. Such a consideration is important for understanding the behavior of spin glass-like phases in a number of real physical systems, mainly in orientational glasses in mixed molecular crystals which present just the case. We build explicitly a full replica symmetry breaking (FRSB) solution of the equations for the orientational glass order parameters when the nonsymmetric part of U{sup -hat} is small. This particular result presents a counterexample in the context of usually adopted conjecture of the absence of FRSB solution in systems with no reflection symmetry.
Tareyeva, E. E.; Schelkacheva, T. I.; Chtchelkatchev, N. M.
2013-02-01
We investigate near the point of glass transition the expansion of the free energy corresponding to the generalized Sherrington-Kirkpatrick model with arbitrary diagonal operators Uˆ standing instead of Ising spins. We focus on the case when Uˆ is an operator with broken reflection symmetry. Such a consideration is important for understanding the behavior of spin glass-like phases in a number of real physical systems, mainly in orientational glasses in mixed molecular crystals which present just the case. We build explicitly a full replica symmetry breaking (FRSB) solution of the equations for the orientational glass order parameters when the nonsymmetric part of Uˆ is small. This particular result presents a counterexample in the context of usually adopted conjecture of the absence of FRSB solution in systems with no reflection symmetry.
Energy Technology Data Exchange (ETDEWEB)
Ezawa, Motohiko, E-mail: ezawa@ap.t.u-tokyo.ac.jp
2014-03-01
The Chern number is a genuine topological number. On the other hand, a symmetry protected topological (SPT) charge is a topological number only when a symmetry exists. We propose a formula for the SPT charge as a derivative of the Chern number in terms of the Green function in such a way that it is valid and related to the associated Hall current even when the symmetry is broken. We estimate the amount of deviation from the quantized value as a function of the strength of the broken symmetry. We present two examples. First, we consider Dirac electrons with the spin–orbit coupling on honeycomb lattice, where the SPT charges are given by the spin-Chern, valley-Chern and spin-valley-Chern numbers. Though the spin-Chern charge is not quantized in the presence of the Rashba coupling, the deviation is estimated to be 10{sup −7} in the case of silicene, a silicon cousin of graphene. Second, we analyze the effect of the mirror-symmetry breaking of the mirror-Chern number in a thin-film of topological crystalline insulator.
Probing maximal zero textures with broken cyclic symmetry in inverse seesaw
Samanta, Rome; Ghosal, Ambar
2016-10-01
Within the framework of inverse seesaw mechanism we investigate neutrino mass matrices invariant under cyclic symmetry (Z3) with maximal zero texture (6 zero textures). We explore two different approaches to obtain the cyclic symmetry invariant form of the constituent matrices. In the first one we consider explicit cyclic symmetry in the neutrino sector of the Lagrangian which dictates the emerged effective neutrino mass matrix (mν) to be symmetry invariant and hence leads to a degeneracy in masses. We then consider explicit breaking of the symmetry through a dimensionless parameter ɛ‧ to remove the degeneracy. It is seen that the method doesn't support the current neutrino oscillation global fit data even after considering the correction from cyclic symmetry invariant charged lepton mass matrix (ml) unless the breaking parameter is too large. In the second method, we assume the same forms of the neutrino mass matrices, however, symmetry is broken in the charged lepton sector. All the structures of the mass matrices are now dictated by an effective residual symmetry of some larger symmetry group in the Lagrangian. For illustration, we exemplify a toy model based on softly broken A4 symmetry group which leads to one of the combinations of ml, mD, MRS and μ to generate effective mν. All the emerged mass matrices predict a constraint range of the CP violating phases and atmospheric mixing angle along with an inverted hierarchical structure of the neutrino masses. Further, significant predictions on ββ 0 ν decay parameter |m11 | and the sum of the three light neutrino masses (Σimi) are also obtained.
Bozin, Emil; Zhong, R.; Knox, K. R.; Winn, B. L.; Gu, G. D.; Hill, J. P.; Tranquada, J. M.; Billinge, S. J. L.
2015-03-01
Revealing the nature of the symmetry broken states in strongly correlated electron systems in general, and in the pseudo-gap (PG) phase of cuprates in particular, is instrumental in understanding the underlying properties. To that effect the knowledge of the local atomic structure may reveal relevant details important for more comprehensive understanding of the character of symmetry broken states in strongly correlated electron systems. Atomic pair distribution function (PDF) is one of the few experimental methods that can speak to this problem. Mounting experimental evidence suggests that the pseudogap phase may represent an electronic state in which the four-fold rotational symmetry of the CuO2 planes is broken, pointing to stripe or nematic character. Systematic approach has been taken in charting both long and short range structural orders, on an equal footing, across the (x, T) phase diagrams of cuprates. For example, in La2-xBaxCuO4, by combining inelastic neutron scattering and neutron PDF approaches, we find evidence consistent with there being a dynamic symmetry breaking well above the charge ordering temperature and within the pseudogap regime. The response has non-monotonic doping dependence that peaks at 1/8 composition. Work at Brookhaven National Laboratory was supported by US DOE, Office of Science, Office of Basic Energy Sciences (DOE-BES) under Contract DE-AC02-98CH10886.
Spontaneously Broken Asymptotic Symmetries and an Effective Action for Horizon Dynamics
Eling, Christopher
2016-01-01
Asymptotic spacetime symmetries have been conjectured to play an important role in quantum gravity. In this paper we study the breaking of asymptotic symmetries associated with a null horizon boundary. In two-dimensions, these symmetries are reparametrizations of the time parameter on the horizon. We show how this horizon reparametrization symmetry is explicitly and spontaneously broken in dilaton gravity and construct an effective action for these pseudo-Goldstone modes using the on-shell gravitational action for a null boundary. The variation of this action yields the horizon constraint equation. This action is invariant under a 2 parameter subgroup of $SL(2)$ transformations, whose Noether charges we interpret via the membrane paradigm. We place these results in the context of recent work on the near $AdS_2$/ near $CFT_1$ correspondence. In this setting the horizon action characterizes the infrared regime near the horizon and has a hydrodynamical sigma model form. We also discuss our construction in Genera...
Broken bond symmetry assists stripe pinning in superconducting La2-xSrxCuO4
Tranquada, John; Jacobsen, H.; Zaliznyak, I. A.; Huecker, M.; Gu, G. D.; Savici, A. T.; Winn, B.; Chang, S.
There has been evidence for quite some time for some degree of charge and spin stripe order in La2-xSrxCuO4 (LSCO). This has been a bit surprising as the crystal structure is supposed to lack the anisotropic Cu-O bonds that lead to robust stripe pinning in La2-xBaxCuO4. Using neutron scattering measurements on the HYSPEC instrument at the Spallation Neutron Source, we have discovered evidence for broken bond symmetry and strong associated lattice fluctuations in an LSCO crystal with x = 0 . 07. The broken bond symmetry occurs within the orthorhombic phase. We also observe quasielastic incommensurate spin excitations that coexist with the bulk superconductivity, suggesting some degree of pair-density-wave order in the superconducting state. Work at BNL supported by Office of Basic Energy Sciences, US DOE, under Contract No. DE-SC00112704.
On the theory of a non-linear neutral scalar field with spontaneously broken symmetry
Poluektov, Yu M
2015-01-01
On the example of a real scalar field, an approach to quantization of non-linear fields and construction of the perturbation theory with account of spontaneous symmetry breaking is proposed. The method is based on using as the main approximation of the relativistic self-consistent field model, in which the influence of vacuum fluctuations is taken into account in constructing the one-particle states. The solutions of the self-consistent equations determine possible states, which also include the states with broken symmetries. Different states of the field are matched to particles, whose masses are determined by both parameters of the Lagrangian and vacuum fluctuations.
CERN. Geneva
2011-01-01
- The discovery of subatomic structures and of the concomitant weak and strong short-range forces raised the question of how to cope with short-range forces in relativistic quantum field theory. The Fermi theory of weak interactions, formulated in terms of point-like current-current interaction, was well-defined in lowest order perturbation theory and accounted for existing experimental data.However, it was inconsistent in higher orders because of uncontrollable divergent quant...
Broken SU(4) Symmetry and The Fractional Quantum Hall Effect in Graphene
Sodemann, Inti; MacDonald, Allan
2014-03-01
We describe a simple variational approach to understand the spin-valley broken symmetry states in the fractional quantum Hall regime of graphene. Our approach allows to predict the incompressible ground states and their charge gaps and is able to explain the observed differences between filling factor ranges | ν | Materials Sciences and Engineering under grant DE-FG03-02ER45958 and by the Welch foundation under grant TBF1473.
A topological approach unveils system invariances and broken symmetries in the brain.
Tozzi, Arturo; Peters, James F
2016-05-01
Symmetries are widespread invariances underscoring countless systems, including the brain. A symmetry break occurs when the symmetry is present at one level of observation but is hidden at another level. In such a general framework, a concept from algebraic topology, namely, the Borsuk-Ulam theorem (BUT), comes into play and sheds new light on the general mechanisms of nervous symmetries. The BUT tells us that we can find, on an n-dimensional sphere, a pair of opposite points that have the same encoding on an n - 1 sphere. This mapping makes it possible to describe both antipodal points with a single real-valued vector on a lower dimensional sphere. Here we argue that this topological approach is useful for the evaluation of hidden nervous symmetries. This means that symmetries can be found when evaluating the brain in a proper dimension, although they disappear (are hidden or broken) when we evaluate the same brain only one dimension lower. In conclusion, we provide a topological methodology for the evaluation of the most general features of brain activity, i.e., the symmetries, cast in a physical/biological fashion that has the potential to be operationalized. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.
Resonant mode conversion in the waveguides with an unbroken and broken PT-symmetry
Vysloukh, Victor A
2014-01-01
We study resonant mode conversion in the PT-symmetric multimode waveguides, where symmetry breaking manifests itself in sequential destabilization (appearance of the complex eigenvalues) of the pairs of adjacent guided modes. We show that the efficient mode conversion is possible even in the presence of the resonant longitudinal modulation of the complex refractive index. The distinguishing feature of the resonant mode conversion in the PT-symmetric structure is a drastic growth of the width of the resonance curve when the gain/losses coefficient approaches a critical value, at which symmetry breaking occurs. We found that in the system with broken symmetry the resonant coupling between exponentially growing mode with stable higher-order one effectively stabilizes dynamically coupled pair of modes and remarkably diminishes the average rate of the total power growth.
Symmetry broken and restored coupled-cluster theory: II. Global gauge symmetry and particle number
Duguet, T.; Signoracci, A.
2017-01-01
We have recently extended many-body perturbation theory (MBPT) and coupled-cluster theory performed on top of a Slater determinant breaking rotational symmetry to allow for the restoration of the angular momentum at any truncation order (Duguet 2015 J. Phys. G: Nucl. Part. Phys. 42 025107). Following a similar route, we presently extend Bogoliubov MBPT and Bogoliubov coupled cluster theory performed on top of a Bogoliubov reference state breaking global gauge symmetry to allow for the restoration of the particle number at any truncation order. Eventually, formalisms can be merged to handle SU(2) and U(1) symmetries at the same time. The long-term goal relates to the ab initio description of near-degenerate finite quantum systems with an open-shell character.
Time reversal symmetry broken fractional topological phases at zero magnetic field
Meng, Tobias; Sela, Eran
2014-12-01
We extend the coupled-wire construction of quantum Hall phases, and search for fractional topological insulating states in models of weakly coupled wires at zero external magnetic field. Focusing on systems beyond double copies of fractional quantum Hall states at opposite fields, we find that spin-spin interactions can stabilize a large family of fractional topological phases with broken time reversal invariance. The latter is manifested by spontaneous spin polarization, by a finite Hall conductivity, or by both. This suggests the possibility that fractional topological insulators may be unstable to spontaneous symmetry breaking.
On (Un)Broken Higher-Spin Symmetry in Vector Models
Skvortsov, E. D.
The simplest consequences of exact and broken higher-spin symmetry are studied. The one-loop anomalous dimensions of higher-spin currents are determined from the multiplet recombination in the spirit of the modern bootstrap programme: the Wilson-Fisher CFT is studied both in the 4-ɛ-expansion and in the large-N. The bulk implications are briefly addressed: part of the higher-spin theory cubic action is reconstructed; one-loop corrections to the AdS masses of higher-spin fields are discussed.
Tennakoon, S G K; Hegseth, J J; Riecke, H; Tennakoon, Sarath G. K.; Hegseth, John. J.; Riecke, Hermann
1996-01-01
The effect of temporal modulation on traveling waves in the flows in two distinct systems of rotating cylinders, both with broken azimuthal symmetry, has been investigated. It is shown that by modulating the control parameter at twice the critical frequency one can excite phase-locked standing waves and standing-wave-like states which are not allowed when the system is rotationally symmetric. We also show how previous theoretical results can be extended to handle patterns such as these, that are periodic in two spatial direction.
Higashikawa, Sho
2016-01-01
A symmetry broken phase of a system with internal degrees of freedom often features a complex order parameter, which generates a rich variety of topological excitations and topological influence between them, yet the very complexity of the order parameter makes it difficult to treat topological excitations and topological influence in a unified manner. To overcome this problem, we develop a general method to calculate homotopy groups and derive decomposition formulas which express homotopy groups of a quotient space $G/H$ in terms of those of the symmetry $G$ of the system and those of the remaining symmetry $H$ of the state. We apply these formulas to analyze a general monopole and a general three-dimensional skyrmion, and show that their textures are obtained through substitution of the corresponding $\\mathfrak{su}(2)$-subalgebra for the $\\mathfrak{su}(2)$-spin. We also show that a discrete symmetry of $H$ is necessary for the presence of topological influence and find the topological influence on a skyrmio...
Spontaneously broken asymptotic symmetries and an effective action for horizon dynamics
Eling, Christopher
2017-02-01
Asymptotic spacetime symmetries have been conjectured to play an important role in quantum gravity. In this paper we study the breaking of asymptotic symmetries associated with a null horizon boundary. In two-dimensions, these symmetries are reparametrizations of the time parameter on the horizon. We show how this horizon reparametrization symmetry is explicitly and spontaneously broken in dilaton gravity and construct an effective action for these pseudo-Goldstone modes using the on-shell gravitational action for a null boundary. The variation of this action yields the horizon constraint equation. This action is invariant under a 2 parameter subgroup of SL(2) transformations, whose Noether charges we interpret via the membrane paradigm. We place these results in the context of recent work on the near AdS2/ near CFT1 correspondence. In this setting the horizon action characterizes the infrared regime near the horizon and has a hydrodynamical sigma model form. We also discuss our construction in General Relativity. In the three-dimensional case there is a natural generalization of our results. However, in higher dimensions, the variation of the effective action only yields the Raychaudhuri equation for small perturbations of the horizon.
Diaconu, C V; Doll, J D; Freeman, D L; Diaconu, Cristian V.; Cho, Art E.; Freeman, David L.
2004-01-01
In the present work we investigate the adequacy of broken-symmetry (BS) unrestricted (U) density functional theory (DFT) for constructing the potential energy curve of nickel dimer and nickel hydride, as model for larger bare and hydrogenated nickel cluster calculations. We use three hybrid functionals: B3LYP, Becke98, and FSLYP (50% Hartree-Fock and 50% Slater exchange and LYP correlation functional) with two basis sets: all-electron (AE) Wachters+f basis set and Stuttgart RSC effective core potential (ECP) and basis set. We find that, overall, B3LYP functional with Wachters+f AE basis set performs best, with only 1.3% root-mean-square (RMS) deviation from experiment, followed by Becke98/AE and B3LYP/ECP, with RMS deviation from experimental value of 2.5% and 2.7%, respectively. We also find that for Ni dimer, the spin-projection for the broken-symmetry unrestricted singlet states changes the ordering of the states, but the splittings are less than 10 meV. All our calculations predict a (delta)(delta)-hole g...
Ye, Jinwu
2005-03-01
We study the interlayer coherent incompressible phase in trilayer quantum Hall systems (TLQH) at total filling factor νT=1 from three approaches: Mutual composite fermion (MCF), composite boson (CB), and wave function approach. Just like in bilayer quantum Hall system, CB approach is superior than MCF approach in studying TLQH with broken symmetry. The Hall and Hall drag resistivities are found to be quantized at h/e2 . Two neutral gapless modes with linear dispersion relations are identified and the ratio of the two velocities is close to 3 . The excitation spectra are classified into two classes, charge neutral bosonic two-body bound states and charge ±1 fermionic three-body bound states. In general, there are two two-body Kosterlize-Thouless (KT) transition temperatures and one three-body KT transition. The charge ±1 three-body fermionic bound states may be the main dissipation source of transport measurements. The broken symmetry in terms of SU (3) algebra is studied. The structure of excitons and their flowing patterns are given. The coupling between the two Goldstone modes will lead to the broadening in the zero-bias peak in the interlayer correlated tunnelings of the TLQH. Several interesting features unique to TLQH are outlined. Limitations of the CB approach are also pointed out.
Zhang, Rong; Li, Qian-Wen; Tang, F. R.; Yang, X. Q.; Bai, L.
2017-08-01
We investigate the performance at a given power of a thermoelectric heat engine with broken time-reversal symmetry, and derive analytically the efficiency at a given power of a thermoelectric generator within linear irreversible thermodynamics. A universal bound on the efficiency of the thermoelectric heat engine is achieved under a strong constraint on the Onsager coefficients, and some interesting features are further revealed. Our results demonstrate that there exists a trade-off between efficiency and power output, and the efficiency at a given power may surpass the Curzon-Ahlborn limit due to broken time-reversal symmetry. Moreover, optimal efficiency at a given power can be achieved, which indicates that broken time-reversal symmetry offers physically allowed ways to optimize the performance of heat engines. Our study may contribute to the interesting guidelines for optimizing actual engines.
Zero-magnetic-field hall effect in broken-mirror-symmetry conductors under illumination.
Edelstein, Victor M
2005-10-07
A novel effect is predicted for conductors with a broken mirror symmetry [e.g., polar metals and asymmetrical quantum well (QW) structures]: if such a conductor is under the direct current J approximately E(d), the circular polarized infrared radiation should induce an additional transverse current JH approximately E(d)xc, where E(d) is the driving electric field and c is a vector directed either along the polar axis or perpendicular to a QW. The sign of the current JH can be reversed by switching the helicity of the light from right to left-handed. Thus the phenomenon is, in fact, something like the Hall effect in which light acts as an external magnetic field.
Adiabatic electronic flux density: a Born-Oppenheimer Broken Symmetry ansatz
Pohl, Vincent
2016-01-01
The Born-Oppenheimer approximation leads to the counterintuitive result of a vanishing electronic flux density upon vibrational dynamics in the electronic ground state. To circumvent this long known issue, we propose using pairwise anti-symmetrically translated vibronic densities to generate a symmetric electronic density that can be forced to satisfy the continuity equation approximately. The so-called Born-Oppenheimer broken symmetry ansatz yields all components of the flux density simultaneously while requiring only knowledge about the nuclear quantum dynamics on the electronic adiabatic ground state potential energy surface. The underlying minimization procedure is transparent and computationally inexpensive, and the solution can be computed from the standard output of any quantum chemistry program. Taylor series expansion reveals that the implicit electron dynamics originates from non-adiabatic coupling to the explicit Born-Oppenheimer nuclear dynamics. The new approach is applied to the ${\\rm H}_2^+$ mo...
Symmetry-broken local-density approximation for one-dimensional systems
Rogers, Fergus J M; Loos, Pierre-François
2016-01-01
Within density-functional theory, the local-density approximation (LDA) correlation functional is typically built by fitting the difference between the near-exact and Hartree-Fock (HF) energies of the uniform electron gas (UEG), together with analytic perturbative results from the high- and low-density regimes. Near-exact energies are obtained by performing accurate diffusion Monte Carlo calculations, while HF energies are usually assumed to be the Fermi fluid HF energy. However, it has been known since the seminal work of Overhauser that one can obtain lower, symmetry-broken (SB) HF energies at any density. Here, we have computed the SBHF energies of the one-dimensional UEG and constructed a SB version of the LDA (SBLDA) from the results. We compare the performance of the LDA and SBLDA functionals when applied to one-dimensional systems, including atoms and molecules. Generalization to higher dimensions is also discussed.
Vacuum Solutions of Neutrino Anomalies Through a Softly Broken $U$(1) symmetry
Joshipura, A S; Joshipura, Anjan S.; Rindani, Saurabh D.
2000-01-01
We discuss an extended SU(2)XU(1) model which naturally leads to mass scales and mixing angles relevant for understanding both the solar and atmospheric neutrino anomalies in terms of the vacuum oscillations of the three known neutrinos. The model uses a softly broken L_e-L_{\\mu}-L_{\\tau} symmetry and contains a heavy scale M_H\\sim 10^{15} GeV. The L_e-L_{\\mu}-L_{\\tau} symmetric neutrino masses solve the atmospheric neutrino anomaly while breaking of L_e-L_{\\mu}-L_{\\tau} generates highly suppressed radiative mass scale problem. All the neutrino masses in the model are inversely related to M_H, thus providing seesaw-type of masses without invoking any heavy right-handed neutrinos. Possible embedding of the model into an SU(5) grand unified theory is discussed.
Zhang, Zhiwang; Wei, Qi; Cheng, Ying; Zhang, Ting; Wu, Dajian; Liu, Xiaojun
2017-02-01
The discovery of topological acoustics has revolutionized fundamental concepts of sound propagation, giving rise to strikingly unconventional acoustic edge modes immune to scattering. Because of the spinless nature of sound, the "spinlike" degree of freedom crucial to topological states in acoustic systems is commonly realized with circulating background flow or preset coupled resonator ring waveguides, which drastically increases the engineering complexity. Here we realize the acoustic pseudospin multipolar states in a simple flow-free symmetry-broken metamaterial lattice, where the clockwise (anticlockwise) sound propagation within each metamolecule emulates pseudospin down (pseudospin up). We demonstrate that tuning the strength of intermolecular coupling by simply contracting or expanding the metamolecule can induce the band inversion effect between the pseudospin dipole and quadrupole, which leads to a topological phase transition. Topologically protected edge states and reconfigurable topological one-way transmission for sound are further demonstrated. These results provide diverse routes to construct novel acoustic topological insulators with versatile applications.
Del Cima, Oswaldo M; Piguet, Olivier
2016-01-01
In this paper, we revisit the issue intensively studied in recent years on the generation of terms by radiative corrections in models with broken Lorentz symmetry. The algebraic perturbative method of handling the problem of renormalization of the theories with Lorentz symmetry breaking, is used. We hope to make clear the Symanzik's aphorism: "{\\it Whether you like it or not, you have to include in the lagrangian all counter terms consistent with locality and power-counting, unless otherwise constrained by Ward identities.}"
Bogoliubov Fermi Surfaces in Superconductors with Broken Time-Reversal Symmetry
Agterberg, D. F.; Brydon, P. M. R.; Timm, C.
2017-03-01
It is commonly believed that, in the absence of disorder or an external magnetic field, there are three possible types of superconducting excitation gaps: The gap is nodeless, it has point nodes, or it has line nodes. Here, we show that, for an even-parity nodal superconducting state which spontaneously breaks time-reversal symmetry, the low-energy excitation spectrum generally does not belong to any of these categories; instead, it has extended Bogoliubov Fermi surfaces. These Fermi surfaces can be visualized as two-dimensional surfaces generated by "inflating" point or line nodes into spheroids or tori, respectively. These inflated nodes are topologically protected from being gapped by a Z2 invariant, which we give in terms of a Pfaffian. We also show that superconducting states possessing these Fermi surfaces can be energetically stable. A crucial ingredient in our theory is that more than one band is involved in the pairing; since all candidate materials for even-parity superconductivity with broken time-reversal symmetry are multiband systems, we expect these Z2-protected Fermi surfaces to be ubiquitous.
Frictional Sliding without Geometrical Reflection Symmetry
Aldam, Michael; Bar-Sinai, Yohai; Svetlizky, Ilya; Brener, Efim A.; Fineberg, Jay; Bouchbinder, Eran
2016-10-01
The dynamics of frictional interfaces plays an important role in many physical systems spanning a broad range of scales. It is well known that frictional interfaces separating two dissimilar materials couple interfacial slip and normal stress variations, a coupling that has major implications on their stability, failure mechanism, and rupture directionality. In contrast, it is traditionally assumed that interfaces separating identical materials do not feature such a coupling because of symmetry considerations. We show, combining theory and experiments, that interfaces that separate bodies made of macroscopically identical materials but lack geometrical reflection symmetry generically feature such a coupling. We discuss two applications of this novel feature. First, we show that it accounts for a distinct, and previously unexplained, experimentally observed weakening effect in frictional cracks. Second, we demonstrate that it can destabilize frictional sliding, which is otherwise stable. The emerging framework is expected to find applications in a broad range of systems.
van Wüllen, Christoph
2009-10-29
Antiferromagnetic coupling in multinuclear transition metal complexes usually leads to electronic ground states that cannot be described by a single Slater determinant and that are therefore difficult to describe by Kohn-Sham density functional methods. Density functional calculations in such cases are usually converged to broken symmetry solutions which break spin and, in many cases, also spatial symmetry. While a procedure exists to extract isotropic Heisenberg (exchange) coupling constants from such calculations, no such approach is yet established for the calculation of magnetic anisotropy energies or zero field splitting parameters. This work proposes such a procedure. The broken symmetry solutions are not only used to extract the exchange couplings but also single-ion D tensors which are then used to construct a (phenomenological) spin Hamiltonian, from which the magnetic anisotropy and the zero-field energy levels can be computed. The procedure is demonstrated for a bi- and a trinuclear Mn(III) model compound.
Absence of the Fifth Force Problem in a Model with Spontaneously Broken Dilatation Symmetry
Guendelman, E I
2007-01-01
A scale invariant model containing dilaton $\\phi$ and dust (as a model of matter) is studied where the shift symmetry $\\phi\\to\\phi +const.$ is spontaneously broken at the classical level due to intrinsic features of the model. The dilaton to matter coupling "constant" $f$ appears to be dependent of the matter density. In normal conditions, i.e. when the matter energy density is many orders of magnitude larger than the dilaton contribution to the dark energy density, $f$ becomes less than the ratio of the "mass of the vacuum" in the volume occupied by the matter to the Planck mass. The model yields this kind of "Archimedes law" without any especial (intended for this) choice of the underlying action and without fine tuning of the parameters. The model not only explains why all attempts to discover a scalar force correction to Newtonian gravity were unsuccessful so far but also predicts that in the near future there is no chance to detect such corrections in the astronomical measurements as well as in the speci...
Liquid Crystal Phases of Molecular Bananas: Polarity and Chirality as Broken Symmetries
Clark, Noel
2006-03-01
The study of the interplay of chirality and polarity has been a particularly rich theme of soft matter science since Meyer's seminal discovery that tilted smectics of chiral molecules are macroscopically polar. This event, and the subsequent realization of polar domains and high-speed electro-optic switching in chiral smectics, engaged the liquid crystal community in a worldwide pursuit of novel smectics for applications, featured by the synthesis of more than 50,000 new liquid crystal compounds, and by a consequent broad diversification of the palette of liquid crystal phases and possibilities for supermolecular ordering. A current important activity in this scenario is the study of polar order in synthetically achiral molecules, for example, in molecular bananas, which, as their shape suggests, might be expected to organize in a polar way. Indeed they do, but beyond this, almost everything learned about them has been surprising, including their persistent tendency to exhibit chirality as a spontaneously broken symmetry. I will discuss some of these new phases and phenomena, including the discovery of fluid conglomerates (Pasteur's experiment in a fluid), triclinic fluid order, chiral twist grain boundary phases of achiral molecules, chirality flipping and field-induced deracemization, ferroelectric and antiferroelectric phases with supermolecular- scale polarization modulation, and chiral thermotropic sponge phases.
Vacuum solutions of neutrino anomalies through a softly broken U(1) symmetry
Energy Technology Data Exchange (ETDEWEB)
Joshipura, A.S.; Rindani, S.D. [Phys. Res. Lab., Ahmedabad (India). Theor. Phys. Group
2000-04-01
We discuss an extended SU(2) x U(1) model which naturally leads to mass scales and mixing angles relevant for understanding both the solar and atmospheric neutrino anomalies in terms of the vacuum oscillations of the three known neutrinos. The model uses a softly broken L{sub e}-L{sub {mu}}-L{sub {tau}} symmetry and contains a heavy scale M{sub H}{proportional_to}10{sup 15} GeV. The L{sub e}-L{sub {mu}}-L{sub {tau}} symmetric neutrino masses solve the atmospheric neutrino anomaly while breaking of L{sub e}-L{sub {mu}}-L{sub {tau}} generates the highly suppressed radiative mass scale {delta}{sub S}{proportional_to}10{sup -10}eV{sup 2} needed for the vacuum solution of the solar neutrino problem. All the neutrino masses in the model are inversely related to M{sub H}, thus providing seesaw-type of masses without invoking any heavy right-handed neutrinos. The possible embedding of the model into an SU(5) grand unified theory is discussed. (orig.)
Intra- and interregional coregulation of opioid genes: broken symmetry in spinal circuits.
Kononenko, Olga; Galatenko, Vladimir; Andersson, Malin; Bazov, Igor; Watanabe, Hiroyuki; Zhou, Xing Wu; Iatsyshyna, Anna; Mityakina, Irina; Yakovleva, Tatiana; Sarkisyan, Daniil; Ponomarev, Igor; Krishtal, Oleg; Marklund, Niklas; Tonevitsky, Alex; Adkins, DeAnna L; Bakalkin, Georgy
2017-01-25
Regulation of the formation and rewiring of neural circuits by neuropeptides may require coordinated production of these signaling molecules and their receptors that may be established at the transcriptional level. Here, we address this hypothesis by comparing absolute expression levels of opioid peptides with their receptors, the largest neuropeptide family, and by characterizing coexpression (transcriptionally coordinated) patterns of these genes. We demonstrated that expression patterns of opioid genes highly correlate within and across functionally and anatomically different areas. Opioid peptide genes, compared with their receptor genes, are transcribed at much greater absolute levels, which suggests formation of a neuropeptide cloud that covers the receptor-expressed circuits. Surprisingly, we found that both expression levels and the proportion of opioid receptors are strongly lateralized in the spinal cord, interregional coexpression patterns are side-specific, and intraregional coexpression profiles are affected differently by left- and right-side unilateral body injury. We propose that opioid genes are regulated as interconnected components of the same molecular system distributed between distinct anatomic regions. The striking feature of this system is its asymmetric coexpression patterns, which suggest side-specific regulation of selective neural circuits by opioid neurohormones.-Kononenko, O., Galatenko, V., Andersson, M., Bazov, I., Watanabe, H., Zhou, X. W., Iatsyshyna, A., Mityakina, I., Yakovleva, T., Sarkisyan, D., Ponomarev, I., Krishtal, O., Marklund, N., Tonevitsky, A., Adkins, D. L., Bakalkin, G. Intra- and interregional coregulation of opioid genes: broken symmetry in spinal circuits.
Quantum oscillations in a bilayer with broken mirror symmetry: A minimal model for YBa2Cu3O6+δ
Maharaj, Akash V.; Zhang, Yi; Ramshaw, B. J.; Kivelson, S. A.
2016-03-01
Using an exact numerical solution and semiclassical analysis, we investigate quantum oscillations (QOs) in a model of a bilayer system with an anisotropic (elliptical) electron pocket in each plane. Key features of QO experiments in the high temperature superconducting cuprate YBCO can be reproduced by such a model, in particular the pattern of oscillation frequencies (which reflect "magnetic breakdown" between the two pockets) and the polar and azimuthal angular dependence of the oscillation amplitudes. However, the requisite magnetic breakdown is possible only under the assumption that the horizontal mirror plane symmetry is spontaneously broken and that the bilayer tunneling t⊥ is substantially renormalized from its `bare' value. Under the assumption that t⊥=Z ˜t⊥(0) , where Z ˜ is a measure of the quasiparticle weight, this suggests that Z ˜≲1 /20 . Detailed comparisons with new YBa2Cu3O6.58 QO data, taken over a very broad range of magnetic field, confirm specific predictions made by the breakdown scenario.
Iyyappan, I.; Ponmurugan, M.
2017-09-01
We study the performance of a three-terminal thermoelectric device such as heat engine and refrigerator with broken time-reversal symmetry by applying the unified trade-off figure of merit (\\dotΩ criterion) which accounts for both useful energy and losses. For the heat engine, we find that a thermoelectric device working under the maximum \\dotΩ criterion gives a significantly better performance than a device working at maximum power output. Within the framework of linear irreversible thermodynamics such a direct comparison is not possible for refrigerators, however, our study indicates that, for refrigerator, the maximum cooling load gives a better performance than the maximum \\dotΩ criterion for a larger asymmetry. Our results can be useful to choose a suitable optimization criterion for operating a real thermoelectric device with broken time-reversal symmetry.
Energy Technology Data Exchange (ETDEWEB)
Del Cima, Oswaldo M.; Franco, Daniel H.T.; Piguet, Olivier, E-mail: opiguet@pq.cnpq.br
2016-11-15
In this paper, we revisit the issue intensively studied in recent years on the generation of terms by radiative corrections in models with broken Lorentz symmetry. The algebraic perturbative method of handling the problem of renormalization of the theories with Lorentz symmetry breaking, is used. We hope to make clear the Symanzik's aphorism: “Whether you like it or not, you have to include in the lagrangian all counter terms consistent with locality and power-counting, unless otherwise constrained by Ward identities.”{sup 1}.
Directory of Open Access Journals (Sweden)
Oswaldo M. Del Cima
2016-11-01
Full Text Available In this paper, we revisit the issue intensively studied in recent years on the generation of terms by radiative corrections in models with broken Lorentz symmetry. The algebraic perturbative method of handling the problem of renormalization of the theories with Lorentz symmetry breaking, is used. We hope to make clear the Symanzik's aphorism: “Whether you like it or not, you have to include in the lagrangian all counter terms consistent with locality and power-counting, unless otherwise constrained by Ward identities.”1
Dark matter reflection of particle symmetry
Khlopov, Maxim Yu.
2017-05-01
In the context of the relationship between physics of cosmological dark matter and symmetry of elementary particles, a wide list of dark matter candidates is possible. New symmetries provide stability of different new particles and their combination can lead to a multicomponent dark matter. The pattern of symmetry breaking involves phase transitions in the very early Universe, extending the list of candidates by topological defects and even primordial nonlinear structures.
Master formula approach to broken chiral U(3)xU(3) symmetry
Energy Technology Data Exchange (ETDEWEB)
Hiroyuki Kamano
2010-04-01
The master formula approach to chiral symmetry breaking proposed by Yamagishi and Zahed is extended to the U_R(3)xU_L(3) group, in which effects of the U_A(1) anomaly and the flavor symmetry breaking m_u \
DEFF Research Database (Denmark)
Andersen, Brian Møller; Graser, S.; Hirschfeld, P. J.
2012-01-01
Recent experimental and theoretical studies have highlighted the possible role of an electronic nematic liquid in underdoped cuprate superconductors. We calculate, within a model of d-wave superconductor with Hubbard correlations, the spin susceptibility in the case of a small explicitly broken...
Barborini, Matteo; Guidoni, Leonardo
2016-09-01
The correct description of the ground state electronic and geometrical properties of multi-centre transition metal complexes necessitates of a high-level description of both dynamical and static correlation effects. In di-metallic complexes, the ground state low spin properties can be computed starting from single-determinants High-Spin (HS) and Broken Symmetry (BS) states by reconstructing an approximated low spin potential energy surface through the extended broken symmetry approach, based on the Heisenberg Hamiltonian. In the present work, we first apply this approach within the variational Monte Carlo method to tackle the geometry optimization of a Fe2S2(SH)42- model complex. To describe the HS and BS wavefunctions, we use a fully optimized unrestricted single determinant with a correlated Jastrow factor able to recover a large amount of dynamical correlation. We compared our results with those obtained by density functional theory and other multiconfigurational approaches, discussing the role of the nodal surface on the structural parameters.
Partial symmetry, reflection monoids and Coxeter groups
Everitt, Brent; Fountain, John
2008-01-01
This is the first of a series of papers in which we initiate and develop the theory of reflection monoids, motivated by the theory of reflection groups. The main results identify a number of important inverse semigroups as reflection monoids, introduce new examples, and determine their orders.
Partial mirror symmetry I: reflection monoids
Everitt, Brent; Fountain, John
2007-01-01
This is the first of a series of papers in which we initiate and develop the theory of reflection monoids, motivated by the theory of reflection groups. The main results identify a number of important inverse semigroups as reflection monoids, introduce new examples, and determine their orders.
Reflection symmetries of Isolated Self-consistent Stellar Systems
An, J; Sanders, J L
2016-01-01
Isolated, steady-state galaxies correspond to equilibrium solutions of the Poisson--Vlasov system. We show that (i) all galaxies with a distribution function depending on energy alone must be spherically symmetric and (ii) all axisymmetric galaxies with a distribution function depending on energy and the angular momentum component parallel to the symmetry axis must also be reflection-symmetric about the plane $z=0$. The former result is Lichtenstein's Theorem, derived here by a method exploiting symmetries of solutions of elliptic partial differential equations, while the latter result is new. These results are subsumed into the Symmetry Theorem, which specifies how the symmetries of the distribution function in configuration or velocity space can control the planes of reflection symmetries of the ensuing stellar system.
Saadatmand, S. N.; McCulloch, I. P.
2017-08-01
We present new numerical tools to analyze symmetry-broken phases in the context of SU (2 ) -symmetric translation-invariant matrix product states (MPS) and density-matrix renormalization-group (DMRG) methods for infinite cylinders, and determine the phase diagram of the geometrically frustrated triangular Heisenberg model with nearest- and next-nearest-neighbor (NN and NNN) interactions. The appearance of Nambu-Goldstone modes in the excitation spectrum is characterized by "tower of states" levels in the momentum-resolved entanglement spectrum. Symmetry-breaking phase transitions are detected by a combination of the correlation lengths and second and fourth cumulants of the magnetic order parameters (which we call the Binder ratio), even though symmetry implies that the order parameter itself is strictly zero. Using this approach, we have identified a 120∘ order, a columnar order, and an algebraic spin liquid (specific to width-6 systems), alongside the previously studied topological spin liquid phase. For the latter, we also demonstrate robustness against chiral perturbations.
Broken symmetries and directed collective energy transport in spatially extended systems
DEFF Research Database (Denmark)
Flach, S.; Zolotaryuk, Yaroslav; Miroshnichenko, A. E.;
2002-01-01
We study the appearance of directed energy current in homogeneous spatially extended systems coupled to a heat bath in the presence of an external ac field E(t) . The systems are described by nonlinear field equations. By making use of a symmetry analysis, we predict the right choice of E(t) and ...
Broken symmetry can yield a positive effective G in conformal gravity
Phillips, Peter R
2015-01-01
We modify the action of Mannheim's conformally invariant model by changing the sign of two coefficients. This breaks conformal symmetry, but results in a cosmology that has a positive effective G and at the same time retains one of the main advantages of the Mannheim model, a possible solution of the cosmological constant problem.
Broken symmetry phase transition in solid p-H 2, o-D 2 and HD: crystal field effects
Freiman, Yu. A.; Hemley, R. J.; Jezowski, A.; Tretyak, S. M.
1999-04-01
We report the effect of the crystal field (CF) on the broken symmetry phase transition (BSP) in solid parahydrogen, orthodeuterium, and hydrogen deuteride. The CF was calculated taking into account a distortion from the ideal HCP structure. We find that, in addition to the molecular field generated by the coupling terms in the intermolecular potential, the Hamiltonian of the system contains a crystal-field term, originating from single-molecular terms in the intermolecular potential. Ignoring the CF is the main cause of the systematic underestimation of the transition pressure, characteristic of published theories of the BSP transition. The distortion of the lattice that gives rise to the negative CF in response to the applied pressure is in accord with the general Le Chatelier-Braun principle.
Cresti, Alessandro; Ortmann, Frank; Louvet, Thibaud; Van Tuan, Dinh; Roche, Stephan
2013-05-10
The role of defect-induced zero-energy modes on charge transport in graphene is investigated using Kubo and Landauer transport calculations. By tuning the density of random distributions of monovacancies either equally populating the two sublattices or exclusively located on a single sublattice, all conduction regimes are covered from direct tunneling through evanescent modes to mesoscopic transport in bulk disordered graphene. Depending on the transport measurement geometry, defect density, and broken sublattice symmetry, the Dirac-point conductivity is either exceptionally robust against disorder (supermetallic state) or suppressed through a gap opening or by algebraic localization of zero-energy modes, whereas weak localization and the Anderson insulating regime are obtained for higher energies. These findings clarify the contribution of zero-energy modes to transport at the Dirac point, hitherto controversial.
Lu, Xiancong; Wu, Ziwen; Zhang, Wuhong; Chen, Lixiang
2014-05-02
The law of angular momentum conservation is naturally linked to the rotational symmetry of the involved system. Here we demonstrate theoretically how to break the rotational symmetry of a uniaxial crystal via the electro-optic Pockels effect. By numerical method based on asymptotic expansion, we discover the 3D structure of polarization singularities in terms of C lines and L surfaces embedded in the emerging light. We visualize the controllable dynamics evolution of polarization singularities when undergoing the Pockels effect, which behaves just like the binary fission of a prokaryotic cell, i.e., the splitting of C points and fission of L lines are animated in analogy with the cleavage of nucleus and division of cytoplasm. We reveal the connection of polarization singularity dynamics with the accompanying generation of orbital angular momentum sidebands. It is unexpected that although the total angular momentum of light is not conserved, the total topological index of C points is conserved.
Influence of broken flavor and C and P symmetry on the quark propagator
Maas, Axel; Mian, Walid Ahmed
2017-02-01
Embedding QCD into the standard model breaks various symmetries of QCD explicitly, especially C and P . While these effects are usually perturbatively small, they can be amplified in extreme environments like merging neutron stars or by the interplay with new physics. To correctly treat these cases requires fully backcoupled calculations. To pave the way for later investigations of hadronic physics, we study the QCD quark propagator coupled to an explicit breaking. This substantially increases the tensor structure even for this simplest correlation function. To cope with the symmetry structure, and covering all possible quark masses, from the top quark mass to the chiral limit, we employ Dyson-Schwinger equations. While at weak breaking the qualitative effects have similar trends as in perturbation theory, even moderately strong breakings lead to qualitatively different effects, non-linearly amplified by the strong interactions.
Influence of broken flavor and C and P symmetry on the quark propagator
Maas, Axel
2016-01-01
Embedding QCD into the standard model breaks various symmetries of QCD explicitly, especially C and P. While these effects are usually perturbatively small, they can be amplified in extreme environments like merging neutron stars or by the interplay with new physics. To correctly treat these cases requires fully backcoupled calculations. To pave the way for later investigations of hadronic physics, we study the QCD quark propagator coupled to an explicit breaking. This substantially increases the tensor structure even for this simplest correlation function. To cope with the symmetry structure, and covering all possible quark masses, from the top quark mass to the chiral limit, we employ Dyson-Schwinger equations. While at weak breaking the qualitative effects have similar trends as in perturbation theory, even moderately strong breakings lead to qualitatively different effects, non-linearly amplified by the strong interactions.
Aspects of Black Holes in Gravitational Theories with Broken Lorentz and Diffeomorphism Symmetries
Satheeshkumar, V H
2015-01-01
Since Stephen Hawking discovered that black holes emit thermal radiation, black holes have become the theoretical laboratories for testing our ideas on quantum gravity. This dissertation is devoted to the study of singularities, the formation of black holes by gravitational collapse and the global structure of spacetime. All our investigations are in the context of a recently proposed approach to quantum gravity, which breaks Lorentz and diffeomorphism symmetries at very high energies.
Boltzmann-Gibbs Distribution of Fortune and Broken Time-Reversible Symmetry in Econodynamics
Ao, P
2005-01-01
Within the description of stochastic differential equations it is argued that the existence of Boltzmann-Gibbs type distribution in economy is independent of the time reversal symmetry in econodynamics. Both power law and exponential distributions can be accommodated by it. The demonstration is based on a mathematical structure discovered during a study in gene regulatory network dynamics. Further possible analogy between equilibrium economy and thermodynamics is explored.
Triplets, Static SU(6), and Spontaneously Broken Chiral SU(3) Symmetry
Nambu, Y.
1966-01-01
I would like to present here my view of the current problems of elementary particle theory. It is largely inspired by the recent successes of SU(3) and SU(6) symmetries, and more or less summarizes what I have been pursuing lately. For the details of individual problems I must refer to the original papers. However, what is emphasized here is not the details, but a coherent overall picture plus some speculations which cannot yet be formulated precisely.
Dynamical Symmetries Reflected in Realistic Interactions
Energy Technology Data Exchange (ETDEWEB)
Sviratcheva, K.D.; Draayer, J.P.; /Louisiana State U.; Vary, J.P.; /Iowa State U. /LLNL, Livermore /SLAC
2007-04-06
Realistic nucleon-nucleon (NN) interactions, derived within the framework of meson theory or more recently in terms of chiral effective field theory, yield new possibilities for achieving a unified microscopic description of atomic nuclei. Based on spectral distribution methods, a comparison of these interactions to a most general Sp(4) dynamically symmetric interaction, which previously we found to reproduce well that part of the interaction that is responsible for shaping pairing-governed isobaric analog 0{sup +} states, can determine the extent to which this significantly simpler model Hamiltonian can be used to obtain an approximate, yet very good description of low-lying nuclear structure. And furthermore, one can apply this model in situations that would otherwise be prohibitive because of the size of the model space. In addition, we introduce a Sp(4) symmetry breaking term by including the quadrupole-quadrupole interaction in the analysis and examining the capacity of this extended model interaction to imitate realistic interactions. This provides a further step towards gaining a better understanding of the underlying foundation of realistic interactions and their ability to reproduce striking features of nuclei such as strong pairing correlations or collective rotational motion.
Observation of Quantum Spin Hall States in InAs/GaSb Bilayers under Broken Time-Reversal Symmetry
Du, Lingjie; Knez, Ivan; Sullivan, Gerard; Du, Rui-Rui
2014-03-01
Topological insulators (TIs) are a novel class of materials with nontrivial surface or edge states. Time-reversal symmetry (TRS) protected TIs are characterized by the Z2 topological invariant. The fate of the Z2 TIs under broken TRS is a fundamental question in understanding the physics of topological matter but remains largely unanswered. Here we show, a two-dimensional TI is realized in an inverted electron-hole bilayer engineered from InAs/GaSb semiconductors which retains robust helical liquid (HL) edge states under a strong magnetic field. Wide conductance plateaus of 2e2/h value are observed; they persist to 10T applied in-plane field before transitioning to a trivial semimetal. In a perpendicular field up to 35T, broken TRS leads to a spatial separation of the movers in Kramers pair and consequently the intra-pair backscattering phase space vanishes, i.e., the conductance increases from 2e2/h in strong fields manifesting chiral edge transport. We propose a phenomenological phases diagram, where inside the topological gap the HL transfers into a ``canned helical state'' driven by perpendicular fields. Our findings suggest that once established, the HL is remarkably resilient and only undergoes adiabatic deformation under TRS breaking. The work at Rice was supported by DOE, NSF, and Welch Foundation.
Reflection symmetry detection using locally affine invariant edge correspondence.
Wang, Zhaozhong; Tang, Zesheng; Zhang, Xiao
2015-04-01
Reflection symmetry detection receives increasing attentions in recent years. The state-of-the-art algorithms mainly use the matching of intensity-based features (such as the SIFT) within a single image to find symmetry axes. This paper proposes a novel approach by establishing the correspondence of locally affine invariant edge-based features, which are superior to the intensity based in the aspects that it is insensitive to illumination variations, and applicable to textureless objects. The locally affine invariance is achieved by simple linear algebra for efficient and robust computations, making the algorithm suitable for detections under object distortions like perspective projection. Commonly used edge detectors and a voting process are, respectively, used before and after the edge description and matching steps to form a complete reflection detection pipeline. Experiments are performed using synthetic and real-world images with both multiple and single reflection symmetry axis. The test results are compared with existing algorithms to validate the proposed method.
Fermionic Response in Finite-Density ABJM Theory with Broken Symmetry
DeWolfe, Oliver; Henriksson, Oscar; Rosen, Christopher
2016-01-01
We calculate fermionic response in domain wall backgrounds of four-dimensional gauged supergravity interpolating between distinct stable AdS vacua, holographically dual to zero-temperature states of ABJM theory at finite density for monopole charge. The backgrounds were found by Bobev et al. and are similar to zero-temperature limits of holographic superconductors, but with a symmetry-breaking source as well. The condensed scalar mixes charged and neutral fields dual to composite fermionic operators in the top-down Dirac equations. Both gapped and gapless bands of stable quasiparticles are found.
Predictivity of models with spontaneously broken non-Abelian discrete flavor symmetries
Chen, Mu-Chun; Fallbacher, Maximilian; Omura, Yuji; Ratz, Michael; Staudt, Christian
2013-08-01
In a class of supersymmetric flavor models predictions are based on residual symmetries of some subsectors of the theory such as those of the charged leptons and neutrinos. However, the vacuum expectation values of the so-called flavon fields generally modify the Kähler potential of the setting, thus changing the predictions. We derive simple analytic formulae that allow us to understand the impact of these corrections on the predictions for the masses and mixing parameters. Furthermore, we discuss the effects on the vacuum alignment and on flavor changing neutral currents. Our results can also be applied to non-supersymmetric flavor models.
Predictivity of models with spontaneously broken non-Abelian discrete flavor symmetries
Chen, Mu-Chun; Omura, Yuji; Ratz, Michael; Staudt, Christian
2013-01-01
In a class of supersymmetric flavor models predictions are based on residual symmetries of some subsectors of the theory such as those of the charged leptons and neutrinos. However, the vacuum expectation values of the so-called flavon fields generally modify the K\\"ahler potential of the setting, thus changing the predictions. We derive simple analytic formulae that allow us to understand the impact of these corrections on the predictions for the masses and mixing parameters. Furthermore, we discuss the effects on the vacuum alignment and on flavor changing neutral currents. Our results can also be applied to non--supersymmetric flavor models.
Atmanspacher, Harald
2003-01-01
Many philosophical and scientific discussions of topics of mind-matter research make implicit assumptions, in various guises, about the distinction between mind and matter. Currently predominant positions are based on either reduction or emergence, providing either monistic or dualistic scenarios. A more-involved framework of thinking, which can be traced back to Spinoza and Leibniz, combines the two scenarios, dualistic (with mind and matter separated) and monistic (with mind and matter unseparated), in one single picture. Based on such a picture, the transition from a domain with mind and matter unseparated to separate mental and material domains can be viewed as a result of a general kind of symmetry breaking, which can be described formally in terms of inequivalent representations. The possibility of whether this symmetry breaking might be connected to the emergence of temporal directions from temporally non-directed or even non-temporal levels of reality will be discussed. Correlations between mental and material aspects of reality could then be imagined as remnants of such primordial levels. Different conceivable types of inequivalent representations would lead to correlations with different characteristics.
Broken axial symmetry as essential feature to predict radiative capture in heavy nuclei
Grosse, Eckart; Massarczyk, Ralph
2014-01-01
Cross sections for neutron capture in the range of unresolved resonances are predicted for more than 140 spin-0 target nuclei with A > 50. Allowing the breaking of spherical and axial symmetry in nearly all these nuclei a combined parameterization for both, level density and photon strength is obtained which employs a surprisingly small number of parameters only. The strength functions used are based on a global fit to IVGDR shapes by the sum of three Lorentzians. They are based on theoretical predictions for the A-dependence of pole energies and spreading widths and add up to the TRK sum rule. For the small spins reached by capture resonance spacings are well described by a level density parameter close to the nuclear matter value; a significant collective enhancement is apparent due to the deviation from axial symmetry. Reliable predictions for compound nuclear reactions also outside the valley of stability (as important for nuclear astrophysics and for the transmutation of nuclear waste) are expected to re...
Broken S_3 Flavor Symmetry of Leptons and Quarks: Mass Spectra and Flavor Mixing Patterns
Xing, Zhi-zhong; Zhou, Shun
2010-01-01
We apply the discrete S_3 flavor symmetry to both lepton and quark sectors of the standard model extended by introducing one Higgs triplet and realizing the type-II seesaw mechanism for finite neutrino masses. The resultant mass matrices of charged leptons (M_l), neutrinos (M_nu), up-type quarks (M_u) and down-type quarks (M_d) have a universal form consisting of two terms: one is proportional to the identity matrix I and the other is proportional to the democracy matrix D. We argue that the textures of M_l, M_u and M_d are dominated by the D term, while that of M_nu is dominated by the I term. This hypothesis implies a near mass degeneracy of three neutrinos and can naturally explain why the mass matrices of charged fermions are strongly hierarchical, why the quark mixing matrix is close to I and why the lepton mixing matrix contains two large angles. We discuss a rather simple perturbation ansatz to break the S_3 symmetry and obtain more realistic mass spectra of leptons and quarks as well as their flavor m...
Broken axial symmetry as essential feature to predict radiative capture in heavy nuclei
Directory of Open Access Journals (Sweden)
E. Grosse
2014-12-01
Full Text Available Cross sections for neutron capture in the range of unresolved resonances are predicted for more than 140 spin-0 target nuclei with A>50. Allowing the breaking of spherical and axial symmetry in nearly all these nuclei a combined parameterization for both level density and photon strength is obtained which employs with surprisingly few fit parameters only. The strength functions used are based on a global fit to IVGDR shapes by the sum of three Lorentzians. They are based on theoretical predictions for the A-dependence of pole energies and spreading widths and add up to the TRK sum rule. For the small spins reached by capture resonance spacings are well described by a level density parameter close to the nuclear matter value; a significant collective enhancement is apparent due to the deviation from axial symmetry. Reliable predictions for compound nuclear reactions also outside the valley of stability – important for nuclear astrophysics and for the transmutation of nuclear waste – are expected to result from the global parameterization presented.
Kirczenow, George
2015-09-01
Valley currents and nonlocal resistances of graphene nanostructures with broken inversion symmetry are considered theoretically in the linear response regime. Scattering state wave functions of electrons entering the nanostructure from the contacts represented by groups of ideal leads are calculated by solving the Lippmann-Schwinger equation and are projected onto the valley state subspaces to obtain the valley velocity fields and total valley currents in the nanostructures. In the tunneling regime when the Fermi energy is in the spectral gap around the Dirac point energy, inversion symmetry breaking is found to result in strong enhancement of the nonlocal four-terminal Büttiker-Landauer resistance and in valley currents several times stronger than the conventional electric current. These strong valley currents are the direct result of the injection of electrons from a contact into the graphene in the tunneling regime. They are chiral and occur near contacts from which electrons are injected into the nanostructure whether or not a net electric current flows through the contact. It is also pointed out that enhanced nonlocal resistances in the linear response regime are not a signature of valley currents arising from the combined effect of the electric field and Berry curvature on the velocities of electrons.
STEM-EELS analysis of multipole surface plasmon modes in symmetry-broken AuAg nanowire dimers
Schubert, Ina; Sigle, Wilfried; van Aken, Peter A.; Trautmann, Christina; Toimil-Molares, Maria Eugenia
2015-03-01
Surface plasmon coupling in nanowires separated by small gaps generates high field enhancements at the position of the gap and is thus of great interest for sensing applications. It is known that the nanowire dimensions and in particular the symmetry of the structures has strong influence on the plasmonic properties of the dimer structure. Here, we report on multipole surface plasmon coupling in symmetry-broken AuAg nanowire dimers. Our dimers, consisting of two nanowires with different lengths and separated by gaps of only 10 to 30 nm, were synthesized by pulsed electrochemical deposition in ion track-etched polymer templates. Electron energy-loss spectroscopy in scanning transmission electron microscopy allows us to resolve up to nine multipole order surface plasmon modes of these dimers spectrally separated from each other. The spectra evidence plasmon coupling between resonances of different multipole order, resulting in the generation of additional plasmonic modes. Since such complex structures require elaborated synthesis techniques, dimer structures with complex composition, morphology and shape are created. We demonstrate that finite element simulations on pure Au dimers can predict the generated resonances in the fabricated structures. The excellent agreement of our experiment on AuAg dimers with finite integration simulations using CST microwave studio manifests great potential to design complex structures for sensing applications.
Democratic Mass Matrices from Broken $O(3)_{L} \\times O(3)_{R}$ Flavor Symmetry
Tanimoto, M; Yanagida, T
1999-01-01
We impose $O(3)_L\\times O(3)_R$ flavor symmetry in the supersymmetric standard model. Three lepton doublets $\\ell_i$ transform as an $O(3)_L$ triplet and three charged leptons $\\bar e_i$ as an $O(3)_R$ triplet, while Higgs doublets $H$ and $\\bar H$ are $O(3)_L\\times O(3)_R$ singlets. We discuss a flavor $O(3)_L\\times O(3)_R$ breaking mechanism that leads to "successful" phenomenological mass matrices, so-called "democratic" ones, in which the large degenerate masses of order $0.1\\eV$ which may be accesible to future double that it is well consistent with the observed quark mass hierarchies and the CKM matrix elements.
Adiabatic continuity and broken symmetry in many-electron systems: A variational perspective
Energy Technology Data Exchange (ETDEWEB)
Baeriswyl, D. [Departement de Physique, Universite de Fribourg, Chemin du Musee 3, 1700 Fribourg (Switzerland)
2011-08-26
Variational wave functions are very useful for describing the panoply of ground states found in interacting many-electron systems. Some particular trial states are ''adiabatically'' linked to a reference state, from which they borrow the essential properties. A prominent example is the Gutzwiller ansatz, where one starts with the filled Fermi sea. A simple soluble example, the anisotropic XY chain, illustrates the adiabatic continuity of this class of wave functions. To describe symmetry breaking, one has to modify the reference state accordingly. Alternatively, a quantum phase transition can be described by a pair of variational wave functions, starting at weak and strong coupling, respectively. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Moreira, Iberio de P. R.; Costa, Ramon; Filatov, Michael; Illas, Francesc
2007-01-01
The performance of density functional theory in estimating the magnetic coupling constant in a series of Cu(II) binuclear complexes is investigated by making use of two open shell formalisms: the broken symmetry and the spin-restricted ensemble-referenced Kohn-Sham methods. The strong dependence of
Using Dynamic Software in Mathematics: The Case of Reflection Symmetry
Tatar, Enver; Akkaya, Adnan; Kagizmanli, Türkan Berrin
2014-01-01
This study was carried out to examine the effects of computer-assisted instruction (CAI) using dynamic software on the achievement of students in mathematics in the topic of reflection symmetry. The study also aimed to ascertain the pre-service mathematics teachers' opinions on the use of CAI in mathematics lessons. In the study, a mixed research…
Bifurcations in Hamiltonian systems with a reflecting symmetry
Bosschaert, M.; Hanssmann, H.
2011-01-01
A reflecting symmetry q 7→ −q of a Hamiltonian system does not leave the symplectic structure dq∧dp invariant and is therefore usually asso- ciated with a reversible Hamiltonian system. However, if q 7→ −q leads to H 7→ −H, then the equations of motion are invariant under the re- flection. This impo
Relaxing the Electroweak Scale: the Role of Broken dS Symmetry
Patil, Subodh P
2016-01-01
Recently, a novel mechanism to address the hierarchy problem has been proposed \\cite{Graham:2015cka}, where the hierarchy between weak scale physics and any putative `cutoff' $M$ is translated into a parametrically large field excursion for the so-called relaxion field, driving the Higgs mass to values much less than $M$ through cosmological dynamics. In its simplest incarnation, the relaxion mechanism requires nothing beyond the standard model other than an axion (the relaxion field) and an inflaton. In this note, we critically re-examine the requirements for successfully realizing the relaxion mechanism and point out that parametrically larger field excursions can be obtained for a given number of e-folds by simply requiring that the background break exact de Sitter invariance. We discuss several corollaries of this observation, including the interplay between the upper bound on the scale $M$ and the order parameter $\\epsilon$ associated with the breaking of dS symmetry, and entertain the possibility that t...
Charmless decays B->pipi, piK and KK in broken SU(3)symmetry
Wu, Y L; Wu, Yue-Liang; Zhou, Yu-Feng
2005-01-01
Charmless B decay modes $B \\to \\pi \\pi, \\pi K$ and $KK$ aresystematically investigated with and without flavor SU(3) symmetry. Independent analyses on $\\pi \\pi$ and $\\pi K$ modes both favor a large ratio between color-suppressed tree ($C$) and tree ($T)$ diagram, which suggests that they are more likely to originate from long distance effects. The sizes of QCD penguin diagrams extracted individually from $\\pi\\pi$, $\\pi K$ and $KK$ modes are found to follow a pattern of SU(3) breaking in agreement with the naive factorization estimates. Global fits to these modes are done under various scenarios of SU(3)relations. The results show good determinations of weak phase $\\gamma$ in consistency with the Standard Model (SM), but a large electro-weak penguin $(P_{\\tmop{EW}})$ relative to $T + C$ with a large relative strong phase are favored, which requires an big enhancement of color suppressed electro-weak penguin ($P_{\\tmop{EW}}^C$) compatible in size but destructively interfering with $P_{\\tmop{EW}}$ within the SM,...
Broken symmetry dielectric resonators for high quality-factor Fano metasurfaces
Campione, Salvatore; Basilio, Lorena I; Warne, Larry K; Langston, William L; Luk, Ting S; Wendt, Joel R; Reno, John L; Keeler, Gordon A; Brener, Igal; Sinclair, Michael B
2016-01-01
We present a new approach to dielectric metasurface design that relies on a single resonator per unit cell and produces robust, high quality-factor Fano resonances. Our approach utilizes symmetry breaking of highly symmetric resonator geoemetries, such as cubes, to induce couplings between the otherwise orthogonal resonator modes. In particular, we design perturbations that couple "bright" dipole modes to "dark" dipole modes whose radiative decay is suppressed by local field effects in the array. Our approach is widely scalable from the near-infrared to radio frequencies. We first unravel the Fano resonance behavior through numerical simulations of a germanium resonator-based metasurface that achieved a quality-factor of ~1300 at ~10.8 um. Then, we present two experimental demonstrations operating in the near-infrared (~1 um): a silicon-based implementation that achieved a quality-factor of ~350; and a gallium arsenide-based structure that achieves a quality-factor of ~600 - the highest near-infrared quality-...
Universal horizons and black holes in gravitational theories with broken Lorentz symmetry
Lin, Kai; Cai, Rong-Gen; Wang, Anzhong
2014-01-01
In this paper, we first show that the definition of the universal horizons studied recently in the khrononmetric theory of gravity can be straightforwardly generalized to other theories that violate the Lorentz symmetry, by simply considering the khronon as a probe field and playing the same role as a Killing vector field. As an application, we study static charged ($D+1$)-dimensional spacetimes in the framework of the healthy (non-projectable) Horava-Lifshitz (HL) gravity in the infrared limit, and find various solutions. Some of them represent Lifshitz space-times with hyperscaling violations, and some have black hole structures. In the latter universal horizons always exist inside the Killing horizons. The surface gravity on them can be either larger or smaller than the surface gravity on the Killing horizons, depending on the space-times considered. Although such black holes are found only in the infrared, we argue that black holes with universal horizons also exist in the full theory of the HL gravity. A...
Formation and function of vacancies in Si/Ge Clathrates: The importance of broken symmetries
Bhattacharya, Amrita; Carbogno, Christian; Scheffler, Matthias; Dr. Matthias Scheffler Team, Prof.
2015-03-01
One promising material class for improved thermoelectrics are the clathrates, i.e., semiconducting host lattices encapsulating guest atom. Even in simple clathrates, such as, Si46 and Ge46, the introduction of guests can result in important but not yet understood effects: In Si hosts, the addition of K (or Ba) results in defect-free K8Si46 (Ba8Si46) phases. In spite of their structural and electronic similitude, Ge hosts behave fundamentally different upon filling, where, the spontaneously formed framework vacancies completely (or partially) balance the electron donated by K (or Ba) guests leading to K8Ge44(orBa8Ge43) clathrates. In this work, we use density-functional theory, carefully validating the exchange correlation functional, to compute the formation energies of vacancies and vacancy complexes in Si- and Ge-hosts as function of the filling of guests. By taking into account of the structural disorder, geometric relaxations, and vibrational entropies, we verify the experimentally found vacancy concentration and the thermodynamic stabilities of these compounds. We can trace back the contrasting behaviour of Si/Ge clathrates upon filling to a curious, charged vacancy induced break in symmetry that occurs in Si but not in Ge hosts.
Mu-tau reflection symmetry with a texture-zero
Nishi, C. C.; Sánchez-Vega, B. L.
2017-01-01
The μτ-reflection symmetry is a simple symmetry capable of predicting all the unknown CP phases of the lepton sector and the atmospheric angle but too simple to predict the absolute neutrino mass scale or the mass ordering. We show that by combining it with a discrete abelian symmetry in a nontrivial way we can additionally enforce a texture-zero and obtain a highly predictive scenario where the lightest neutrino mass is fixed to be in the few meV range for two normal ordering (NO) solutions or in the tens of meV in one inverted ordering (IO) solution. The rate for neutrinoless double beta decay is predicted to be negligible for NO or have effective mass m ββ ≈ 14-29 meV for IO, right in the region to be probed in future experiments.
Mu-tau reflection symmetry with a texture-zero
Nishi, C C
2016-01-01
The $\\mu\\tau$-reflection symmetry is a simple symmetry capable of predicting all the unknown CP phases of the lepton sector and the atmospheric angle but too simple to predict the absolute neutrino mass scale or the mass ordering. We show that by combining it with a discrete abelian symmetry in a nontrivial way we can additionally enforce a texture-zero and obtain a highly predictive scenario where the lightest neutrino mass is fixed to be in the few meV range for two normal ordering (NO) solutions or in the tens of meV in one inverted ordering (IO) solution. The rate for neutrinoless double beta decay is predicted to be negligible for NO or have effective mass $m_{\\beta\\beta}\\approx 14\\text{ -- }29\\,{\\rm meV}$ for IO, right in the region to be probed in future experiments.
Directory of Open Access Journals (Sweden)
Christoph P. Hofmann
2016-03-01
Full Text Available The low-temperature properties of systems characterized by a spontaneously broken internal rotation symmetry, O(N→O(N−1, are governed by Goldstone bosons and can be derived systematically within effective Lagrangian field theory. In the present study we consider systems living in two spatial dimensions, and evaluate their partition function at low temperatures and weak external fields up to three-loop order. Although our results are valid for any such system, here we use magnetic terminology, i.e., we refer to quantum spin systems. We discuss the sign of the (pseudo-Goldstone boson interaction in the pressure, staggered magnetization, and susceptibility as a function of an external staggered field for general N. As it turns out, the d=2+1 quantum XY model (N=2 and the d=2+1 Heisenberg antiferromagnet (N=3, are rather special, as they represent the only cases where the spin-wave interaction in the pressure is repulsive in the whole parameter regime where the effective expansion applies. Remarkably, the d=2+1 XY model is the only system where the interaction contribution in the staggered magnetization (susceptibility tends to positive (negative values at low temperatures and weak external field.
Thick domain wall spacetimes with and without reflection symmetry
Melfo, A; Skirzewski, A; Melfo, Alejandra; Pantoja, Nelson; Skirzewski, Aureliano
2003-01-01
We show that the spacetimes of domain wall solutions to the coupled Einstein-scalar field equations with a given scalar field potential fall into two classes, depending on whether or not reflection symmetry on the wall is imposed. Solutions with reflection symmetry are dynamic, while the asymmetric ones are static. Asymmetric walls are asymptotically flat on one side and reduce to the Taub spacetime on the other. Examples of asymmetric thick walls in D-dimensional spacetimes are given, and results on the thin-wall limit of the dynamic, symmetric walls are extended to the asymmetric case. The particular case of symmetric, static spacetimes is considered and a new family of solutions, including previously known BPS walls, is presented.
Reflection symmetries of Isolated Self-consistent Stellar Systems
An, J; Evans, N.W.; Sanders, J. L.
2016-01-01
Isolated, steady-state galaxies correspond to equilibrium solutions of the Poisson--Vlasov system. We show that (i) all galaxies with a distribution function depending on energy alone must be spherically symmetric and (ii) all axisymmetric galaxies with a distribution function depending on energy and the angular momentum component parallel to the symmetry axis must also be reflection-symmetric about the plane $z=0$. The former result is Lichtenstein's Theorem, derived here by a method exploit...
Generalized $\\mu-\\tau$ reflection symmetry and leptonic CP violation
Chen, Peng; Gonzalez-Canales, Felix; Valle, J W F
2016-01-01
We propose a generalized $\\mu-\\tau$ reflection symmetry to constrain the lepton flavor mixing parameters. We obtain a new correlation between the atmospheric mixing angle $\\theta_{23}$ and the "Dirac" CP violation phase $\\delta_{\\rm CP}$. Only in a specific limit our proposed CP transformation reduces to standard $\\mu-\\tau$ reflection, for which $\\theta_{23}$ and $\\delta_{CP}$ are both maximal. The "Majorana" phases are predicted to lie at their CP-conserving values with important implications for the neutrinoless double beta decay rates. We also study the phenomenological implications of our scheme for present and future neutrino oscillation experiments including T2K, NO$\
Using dynamic software in mathematics: the case of reflection symmetry
Tatar, Enver; Akkaya, Adnan; Berrin Kağizmanli, Türkan
2014-10-01
This study was carried out to examine the effects of computer-assisted instruction (CAI) using dynamic software on the achievement of students in mathematics in the topic of reflection symmetry. The study also aimed to ascertain the pre-service mathematics teachers' opinions on the use of CAI in mathematics lessons. In the study, a mixed research method was used. The study group of this research consists of 30 pre-service mathematics teachers. The data collection tools used include a reflection knowledge test, a survey and observations. Based on the analysis of the data obtained from the study, the use of CAI had a positive effect on achievement in the topic of reflection symmetry of the pre-service mathematics teachers. The pre-service mathematics teachers were found to largely consider that a mathematics education which is carried out utilizing CAI will be more beneficial in terms of 'visualization', 'saving of time' and 'increasing interest/attention in the lesson'. In addition, it was found that the vast majority of them considered using computers in their teaching on the condition that the learning environment in which they would be operating has the appropriate technological equipment.
The secret symmetries of the AdS/CFT reflection matrices
Regelskis, Vidas
2011-01-01
We find new twisted Yangian symmetries of the AdS/CFT reflection matrices for the Y=0 maximal giant graviton and D5-brane. These new symmetries originate from the known secret symmetries of the Yangian symmetry of the AdS/CFT S-matrix.
Energy Technology Data Exchange (ETDEWEB)
Xia, Jing
2010-04-05
Polar Kerr effect in the spin-triplet superconductor Sr{sub 2}RuO{sub 4} was measured with high precision using a Sagnac interferometer with a zero-area Sagnac loop. We observed non-zero Kerr rotations as big as 65 nanorad appearing below T{sub c} in large domains. Our results imply a broken time reversal symmetry state in the superconducting state of Sr{sub 2}RuO{sub 4}, similar to {sup 3}He-A.
Lai, M Y; Chou, J P; Utas, O A; Denisov, N V; Kotlyar, V G; Gruznev, D; Matetsky, A; Zotov, A V; Saranin, A A; Wei, C M; Wang, Y L
2011-04-22
Depositing particles randomly on a 1D lattice is expected to result in an equal number of particle pairs separated by even or odd lattice units. Unexpectedly, the even-odd symmetry is broken in the self-selection of distances between indium magic-number clusters on a Si(100)-2×1 reconstructed surface. Cluster pairs separated by even units are less abundant because they are linked by silicon atomic chains carrying topological solitons, which induce local strain and create localized electronic states with higher energy. Our findings reveal a unique particle-particle interaction mediated by the presence or absence of topological solitons on alternate lattices.
Field symmetry, reflected in the design of antennas
Nechaj, Lyubov D.
2014-01-01
Antenna possesses geometric properties that characterize the quality of resonance, antenna has a main purpose: to increase the probability of the observed sharp resonance. Spherical, conical symmetry, cylindrical, coaxial symmetry, the symmetry of plane and the square are the main types of symmetry, which characterize the change in the field and can be used in various combinations for constructing a spatial structure of antennas. Thus, it turns out that in the constructions is enough use of s...
Kobayashi, Michikazu
2014-01-01
We show that a momentum operator of a translational symmetry may not commute with an internal symmetry operator in the presence of a topological soliton in non-relativistic theories. As a striking consequence, there appears a coupled Nambu-Goldstone mode with a quadratic dispersion consisting of translational and internal zero modes in the vicinity of a domain wall in an O(3) sigma model, a magnetic domain wall in ferromagnets with an easy axis.
Goldstein, Raymond Ethan
The longstanding problem of the precise correspondence between critical phenomena in fluids and ferromagnets is resolved in Part I through a synthesis of mean field theory, exact results for lattice models, field-theoretic techniques, and by extensive quantitative comparison with experiment. Emphasis is placed on the origin of broken particle-hole symmetry in fluids as reflected in the form of the critical point scaling fields and in systematic variations in certain nonuniversal critical amplitudes with molecular polarizability. Those trends and the degree to which the scaling axes are linearly mixed versions of the bare "thermal" and "magnetic" fields in particle-hole symmetric systems are shown both for lattice models and real fluids to be intimately related to the presence of many-body interactions of the Axilrod-Teller type. A quantitatively accurate microscopic expression for the field-mixing operator of fluids is derived on the basis of an exact Hubbard-Stratonovich transformation relating the fluid Hamiltonian to that of a Landau-Ginzburg-Wilson model. A phenomenological theory of the phase behavior of multilamellar liquid crystals of hydrated phospholipid bilayers is developed in Part II, and its predictions tested by extensive comparison with experiment. A Ginzburg-Landau free energy functional based on the elastic properties of two coupled monolayers is proposed to describe intrabilayer ordering, and the phenomenon of structural phase transitions driven by membrane interactions is described by incorporating in addition the attractive dispersion interactions and repulsive "hydration" forces acting between membranes. The theory indicates and experiments support a connection between the pseudocriticality of the bilayer transitions and the large susceptibility of the in-plane order to membrane interactions. The pseudocriticality in turn is suggested to arise from the analog of a capillary critical point accessible by finite-size effects. Theoretical phase
Becker, Daniel
2014-01-01
The most momentous requirement a quantum theory of gravity must satisfy is Background Independence, necessitating in particular an ab initio derivation of the arena all non-gravitational physics takes place in, namely spacetime. Using the background field technique, this requirement translates into the condition of an unbroken split-symmetry connecting the (quantized) metric fluctuations to the (classical) background metric. If the regularization scheme used violates split-symmetry during the quantization process it is mandatory to restore it in the end at the level of observable physics. In this paper we present a detailed investigation of split-symmetry breaking and restoration within the Effective Average Action (EAA) approach to Quantum Einstein Gravity (QEG) with a special emphasis on the Asymptotic Safety conjecture. In particular we demonstrate for the first time in a non-trivial setting that the two key requirements of Background Independence and Asymptotic Safety can be satisfied simultaneously. Care...
DEFF Research Database (Denmark)
Denisov, S.; Flach, S.; Ovchinnikov, A. A.
2002-01-01
We consider low-dimensional dynamical systems exposed to a heat bath and to additional ac fields. The presence of these ac fields may lead to a breaking of certain spatial or temporal symmetries, which in turn cause nonzero averages of relevant observables. Nonlinear (non)adiabatic response is em...
Aspelmeier, T.; Wang, Wenlong; Moore, M. A.; Katzgraber, Helmut G.
2016-08-01
The one-dimensional Ising spin-glass model with power-law long-range interactions is a useful proxy model for studying spin glasses in higher space dimensions and for finding the dimension at which the spin-glass state changes from having broken replica symmetry to that of droplet behavior. To this end we have calculated the exponent that describes the difference in free energy between periodic and antiperiodic boundary conditions. Numerical work is done to support some of the assumptions made in the calculations and to determine the behavior of the interface free-energy exponent of the power law of the interactions. Our numerical results for the interface free-energy exponent are badly affected by finite-size problems.
Energy Technology Data Exchange (ETDEWEB)
Hupin, G; Lacroix, D [Grand Accelerateur National d' Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, Bvd Henri Becquerel, 14076 Caen (France); Bender, M, E-mail: hupin@ganil.fr, E-mail: lacroix@ganil.fr, E-mail: bender@ganil.fr [Universite Bordeaux, Centre d' Etudes Nucleaires de Bordeaux Gradignan, UMR5797, F-33175 Gradignan (France)
2011-09-16
The Multi-Reference Energy Density Functional (MR-EDF) approach (also called configuration mixing or Generator Coordinate Method), that is commonly used to treat pairing in finite nuclei and project onto particle number, is re-analyzed. It is shown that, under certain conditions, the MR-EDF energy can be interpreted as a functional of the one-body density matrix of the projected state with good particle number. Based on this observation, we propose a new approach, called Symmetry-Conserving EDF (SC-EDF), where the breaking and restoration of symmetry are accounted for simultaneously. We show, that such an approach is free from pathologies recently observed in MR-EDF and can be used with a large flexibility on the density dependence of the functional.
Non-vanishing $U_{e3}$ and $\\cos{2 \\theta_{23}}$ from a broken $Z_2$ symmetry
Grimus, Walter; Kaneko, S; Lavoura, L; Sawanaka, H; Tanimoto, M; Grimus, Walter; Joshipura, Anjan S.; Kaneko, Satoru; Lavoura, Lu\\'{i}s; Sawanaka, Hideyuki; Tanimoto, Morimitsu
2004-01-01
It is shown that the neutrino mass matrices in the flavour basis yielding a vanishing $U_{e3}$ are characterized by invariance under a class of effective $Z_2$ symmetries. A specific $Z_2$ in this class also leads to a maximal atmospheric mixing angle $\\theta_{23}$. The breaking of that $Z_2$ can be parameterized by two dimensionless quantities, $\\e$ and $\\e'$; the effects of $\\e, \\e' \
Shirkov, D V
2009-01-01
A retrospective historical overview of the phenomenon of spontaneous symmetry breaking (SSB) in quantum theory, the issue that has been implemented in particle physics in the form of the Higgs mechanism. The main items are: -- The Bogoliubov's microscopical theory of superfluidity (1946); -- The BCS-Bogoliubov theory of superconductivity (1957); -- Superconductivity as a superfluidity of Cooper pairs (Bogoliubov - 1958); -- Transfer of the SSB into the QFT models (early 60s); -- The Higgs model triumph in the electro-weak theory (early 80s). The role of the Higgs mechanism and its status in the current Standard Model is also touched upon.
Alexandru, Andrei
2014-01-01
The validity of recently proposed equivalence between valence spontaneous chiral symmetry breaking (vSChSB) and chiral polarization of low energy Dirac spectrum (ChP) in SU(3) gauge theory, is examined for the case of twelve mass-degenerate fundamental quark flavors. We find that the vSChSB-ChP correspondence holds for regularized systems studied. Moreover, our results suggest that vSChSB occurs in two qualitatively different circumstances: there is a quark mass $m_c$ such that for $m > m_c$ the mode condensing Dirac spectrum exhibits standard monotonically increasing density, while for $m_{ch} < m < m_c$ the peak around zero separates from the bulk of the spectrum, with density showing a pronounced depletion at intermediate scales. Valence chiral symmetry restoration may occur at yet smaller masses $m < m_{ch}$, but this has not yet been seen by overlap valence probe, leaving the $m_{ch}=0$ possibility open. The latter option could place massless N$_f$=12 theory outside of conformal window. Anomalou...
Reta, Daniel; Moreira, Ibério de P R; Illas, Francesc
2016-07-12
In the most general case of three electrons in three symmetry unrelated centers with Ŝ1 = Ŝ2 = Ŝ3 = 1/2 localized magnetic moments, the low energy spectrum consists of one quartet (Q) and two doublet (D1, D2) pure spin states. The energy splitting between these spin states can be described with the well-known Heisenberg-Dirac-Van Vleck (HDVV) model spin Hamiltonian, and their corresponding energy expressions are expressed in terms of the three different two-body magnetic coupling constants J12, J23, and J13. However, the values of all three magnetic coupling constants cannot be extracted using the calculated energy of the three spin-adapted states since only two linearly independent energy differences between pure spin states exist. This problem has been recently investigated by Reta et al. (J. Chem. Theory Comput. 2015, 11, 3650), resulting in an alternative proposal to the original Noodleman's broken symmetry mapping approach. In the present work, this proposal is validated by means of ab initio effective Hamiltonian theory, which allows a direct extraction of all three J values from the one-to-one correspondence between the matrix elements of both effective and HDVV Hamiltonian. The effective Hamiltonian matrix representation has been constructed from configuration interaction wave functions for the three spin states obtained for two model systems showing a different degree of delocalization of the unpaired electrons. These encompass a trinuclear Cu(II) complex and a π-conjugated purely organic triradical.
an analysis of learner preconceptions of reflective symmetry
African Journals Online (AJOL)
tive symmetry with the aim of understanding: (a) preconceptions that were common ... vantaged communities, where language problems have been documented, .... develop an 'a posteriori' framework for justifying our descriptions of learner res ..... Conference of European Research in Mathematics Education, Bellaria, Italy.
Retrieval of aerosol optical depth in vicinity of broken clouds from reflectance ratios: case study
Directory of Open Access Journals (Sweden)
E. Kassianov
2010-10-01
Full Text Available A recently developed reflectance ratio (RR method for the retrieval of aerosol optical depth (AOD is evaluated using extensive airborne and ground-based data sets collected during the Cloud and Land Surface Interaction Campaign (CLASIC and the Cumulus Humilis Aerosol Processing Study (CHAPS, which took place in June 2007 over the US Department of Energy (DOE Atmospheric Radiation Measurement (ARM Southern Great Plains site. A detailed case study is performed for a field of single-layer shallow cumuli observed on 12 June 2007. The RR method is applied to retrieve the spectral values of AOD from the reflectance ratios measured by the MODIS Airborne Simulator (MAS for two pairs of wavelengths (660 and 470 nm, 870 and 470 nm collected at a spatial resolution of 0.05 km. The retrieval is compared with an independent AOD estimate from three ground-based Multi-filter Rotating Shadowband Radiometers (MFRSRs. The interpolation algorithm that is used to project MFRSR point measurements onto the aircraft flight tracks is tested using AOD derived from NASA Langley High Spectral Resolution Lidar (HSRL. The RR AOD estimates are in a good agreement (within 5% with the MFRSR-derived AOD values for the 660-nm wavelength. The AODs obtained from MAS reflectance ratios overestimate those derived from MFRSR measurements by 15–30% for the 470-nm wavelength and underestimate the 870-nm AOD by the same amount.
Reflection algebra, Yangian symmetry and bound-states in AdS/CFT
MacKay, Niall
2011-01-01
We present the `Heisenberg picture' of the reflection algebra by explicitly constructing the boundary Yangian symmetry of the AdS/CFT superstring ending on a boundary with degrees of freedom and preserving all of the bulk symmetry algebra. This enables us to present the bound-state reflection matrices in a more elegant, rapidity-difference form. We also consider the spectrum of bulk and boundary states and some automorphisms of the underlying algebras.
Robnik, M; Prosen, T; Robnik, Marko; Dobnikar, Jure; Prosen, Tomaz
1999-01-01
Energy spectra of a particle with mass $m$ and charge $e$ in the cubic Aharonov-Bohm billiard containing around $10^4$ consecutive levels starting from the ground state have been analysed. The cubic Aharonov-Bohm billiard is a plane billiard defined by the cubic conformal mapping of the unit disc pervaded by a point magnetic flux through the origin perpendicular to the plane of the billiard. The magnetic flux does not influence the classical dynamics, but breaks the antiunitary symmetry in the system, which affects the statistics of energy levels. By varying the shape parameter $\\lam$ the classical dynamics goes from integrable ($\\lam =0$) to fully chaotic ($\\lam = 0.2$; Africa billiard). The level spacing distribution $P(S)$ and the number variance interval ($0\\le\\lam\\le0.2$). GUE statistics has proven correct for completely chaotic case, while in the mixed regime the fractional power law level repulsion has been observed. The exponent of the level repulsion has been analysed and is found to change smoothly ...
Chirally Invariant Avatar in a Model of Neutrinos with Light Cone Reflection Symmetry
Chodos, Alan
2016-01-01
In previous work we developed a model of neutrinos based on a new symmetry, Light Cone Reflection (LCR), that interchanges spacelike and timelike intervals. In this paper we start with the four-dimensional model, and construct a two-dimensional avatar that obeys the same equations of motion, and preserves both the light-cone reflection symmetry and the chiral symmetry of the original theory. The avatar also contains the interaction that rendered the four-dimensional model gauge invariant. In an addendum, we make some remarks about how to determine the scalar field that enters into the definition of the LCR-covariant derivative.
The role of broken symmetry in solvation of a spherical cavity in classical and quantum water models
Energy Technology Data Exchange (ETDEWEB)
Remsing, Richard C.; Baer, Marcel D.; Schenter, Gregory K.; Mundy, Christopher J.; Weeks, John D.
2014-08-21
Insertion of a hard sphere cavity in liquid water breaks translational symmetry and generates an electrostatic potential difference between the region near the cavity and the bulk. Here, we clarify the physical interpretation of this potential and its calculation. We also show that the electrostatic potential in the center of small, medium, and large cavities depends very sensitively on the form of the assumed molecular interactions for dfferent classical simple point-charge models and quantum mechanical DFT-based interaction potentials, as reected in their description of donor and acceptor hydrogen bonds near the cavity. These dfferences can signifcantly affect the magnitude of the scalar electrostatic potential. We argue that the result of these studies will have direct consequences toward our understanding of the thermodynamics of ion solvation through the cavity charging process. JDW and RCR are supported by the National Science Foundation (Grants CHE0848574 and CHE1300993). CJM and GKS are supported by the U.S. Department of Energy`s (DOE) Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences. Pacific Northwest National Laboratory (PNNL) is operated for the Department of Energy by Battelle. MDB is grateful for the support of the Linus Pauling Distinguished Postdoctoral Fellowship Program at PNNL. We acknowledge illuminating discussions and sharing of ideas and preprints with Dr. Shawn M. Kathmann and Prof. Tom Beck. The DFT simulations used resources of the National Energy Research Scientific Computing Center, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Additional computing resources were generously allocated by PNNL's Institutional Computing program.
Kishi, Ryohei; Nakano, Masayoshi
2011-04-21
A novel method for the calculation of the dynamic polarizability (α) of open-shell molecular systems is developed based on the quantum master equation combined with the broken-symmetry (BS) time-dependent density functional theory within the Tamm-Dancoff approximation, referred to as the BS-DFTQME method. We investigate the dynamic α density distribution obtained from BS-DFTQME calculations in order to analyze the spatial contributions of electrons to the field-induced polarization and clarify the contributions of the frontier orbital pair to α and its density. To demonstrate the performance of this method, we examine the real part of dynamic α of singlet 1,3-dipole systems having a variety of diradical characters (y). The frequency dispersion of α, in particular in the resonant region, is shown to strongly depend on the exchange-correlation functional as well as on the diradical character. Under sufficiently off-resonant condition, the dynamic α is found to decrease with increasing y and/or the fraction of Hartree-Fock exchange in the exchange-correlation functional, which enhances the spin polarization, due to the decrease in the delocalization effects of π-diradical electrons in the frontier orbital pair. The BS-DFTQME method with the BHandHLYP exchange-correlation functional also turns out to semiquantitatively reproduce the α spectra calculated by a strongly correlated ab initio molecular orbital method, i.e., the spin-unrestricted coupled-cluster singles and doubles.
Inotani, Daisuke; Hanai, Ryo; Ohashi, Yoji
2016-10-01
We extend our recent work [Y. Endo et al., Phys. Rev. A 92, 023610 (2015)], 10.1103/PhysRevA.92.023610 for a parity-mixing effect in a model of two-dimensional lattice fermions to a realistic three-dimensional ultracold Fermi gas. Including effects of broken local spatial inversion symmetry by a trap potential within the framework of the real-space Bogoliubov-de Gennes theory at T =0 , we point out that an odd-parity p -wave Cooper-pair amplitude is expected to have already been realized in previous experiments on an (even-parity) s -wave superfluid Fermi gas with spin imbalance. This indicates that when one suddenly changes the s -wave pairing interaction to an appropriate p -wave one by using a Feshbach technique in this case, a nonvanishing p -wave superfluid order parameter is immediately obtained, which is given by the product of the p -wave interaction and the p -wave pair amplitude that has already been induced in the spin-imbalanced s -wave superfluid Fermi gas. Thus, by definition, the system is in the p -wave superfluid state, at least just after this manipulation. Since the achievement of a p -wave superfluid state is one of the most exciting challenges in cold Fermi gas physics, our results may provide an alternative approach to this unconventional pairing state. In addition, since the parity-mixing effect cannot be explained as far as one deals with a trap potential in the local density approximation (LDA), it is considered as a crucial example which requires us to go beyond the LDA.
Miao, Ludi; Xin, Yan; Zhu, Huiwen; Xu, Hong; Luo, Sijun; Talbayev, Diyar; Stanislavchuk, T. N.; Sirenko, A. A.; Mao, Zhiqiang
2014-03-01
Materials with colossal permittivity (CP) at room temperature hold tremendous promise in modern microelectronics as well as high-energy-density storage applications. Despite several proposed mechanisms that lead torecent discoveries of a series of new CP materials such as Nb, In co-doped TiO2 and CaCu3Ti4O12 ceramics, it is imperative to find other approaches which can further guide the search for new CP materials. In this talk, we will demonstrate a new mechanism for CP: the breaking of mirror reflection symmetry of lattice can cause CP. This mechanism was revealed in a new layered iridate Ba7Ir3O13+x (BIO) thin film we recently discovered. Structural characterization of BIO films show that its mirror reflection symmetry is broken along b-axis, but preserved along a- and c-axes. Dielectric property measurements of BIO films at room temperature show a CP (103-10<4) along the in-plane direction, but a much smaller permittivity (10- 20) along the c-axis, in the 102- 106 Hz frequency range. Such unusually large anisotropy in permittivity testifies to the significant role of the structural in-plane mirror reflection symmetry breaking in inducing CP. This work is supported by DOD-ARO under Grant No. W911NF0910530.
Consistencies far beyond chance: an analysis of learner preconceptions of reflective symmetry
Directory of Open Access Journals (Sweden)
Michael Kainose Mhlolo
2013-01-01
Full Text Available This article reports on regularities observed in learners' preconceptions of reflective symmetry. Literature suggests that the very existence of such regularities indicates a gap between what learners know and what they need to know. Such a gap inhibits further understanding and application, and hence needed to be investigated. A total of 235 Grade 11 learners, from 13 high schools that participate in the First Rand Foundation-funded Mathematics Education project in the Eastern Cape, responded to a task on reflective symmetry. Our framework for analysing the responses was based on the taxonomy of structure of the observed learning outcome. The results indicated that 85% of learner responses reflect a motion understanding of reflections, where learners considered geometric figures as physical motions on top of the plane. While this understanding is useful in some cases, it is not an essential aspect of mapping understanding, which is critical for application in function notations and other analytical geometry contexts. We suggest that if this gap is to be closed, learners need to construct these reflections physically so that they may think of reflections beyond motion.
Effect of the reflectional symmetry on the coherent hole transport across DNA hairpins
Zarea, Mehdi; Berlin, Yuri; Ratner, Mark A.
2017-03-01
The coherent hole transfer in three types of DNA hairpins containing strands with adenine (A) and guanine (G) nucleobases has been studied. The investigated hairpins involve An+1GGAn, AnGAGAn, or (AG)2nA strands that connect the hole donor and hole acceptor located on opposite ends of hairpins. The positive charge transfer from the photo-excited donor to the acceptor is shown to be slower for An+1GGAn in comparison with AnGAGAn and (AG)2nA sequences. We have revealed that this is due to the reflectional symmetry of the last two sequences with respect to the axis passing through the middle base. As has been demonstrated, the symmetry of the sequence structure manifests itself in the reflectional symmetry of the energy eigenstates. In addition, it has been shown that (AG)2nA is the only symmetric sequence with a zero energy state in the middle of the LUMO tight-binding energy band. Based on our theoretical findings, we predict that the hairpin with this sequence should have the fastest coherent hole transfer rate among the class of base sequences studied.
Designing Reflection and Symmetry Learning by Using Math Traditional Dance in Primary School
Directory of Open Access Journals (Sweden)
Yullys Helsa
2011-01-01
Full Text Available The innovation of education is an important point of Pendidikan Matematika Realistik Indonesia (PMRI, one of them through traditional dance as a context of national cultural. Dance that collaborated with concept of mathematics, it is called Math Traditional Dance. This research aims to produce learning line (specific the material of reflection and symmetry. The research method used is design research that consisted of preparing for the experiments, teaching experiments, and retrospective analysis. Data collected through observation, interviews, documentation and field notes. This research was conducted with 22 students in MIN 2 Palembang. From the try out that is obtained from the formal to the informal learning described in the learning process, so that support learning process of mirroring and symmetry for the students in grade four in elementary school.
On the Symmetry of Molecular Flows Through the Pipe of an Arbitrary Shape (I) Diffusive Reflection
Kusumoto, Yoshiro
Molecular gas flows through the pipe of an arbitrary shape is mathematically considered based on a diffusive reflection model. To avoid a perpetual motion, the magnitude of the molecular flow rate must remain invariant under the exchange of inlet and outlet pressures. For this flow symmetry, the cosine law reflection at the pipe wall was found to be sufficient and necessary, on the assumption that the molecular flux is conserved in a collision with the wall. It was also shown that a spontaneous flow occurs in a hemispherical apparatus, if the reflection obeys the n-th power of cosine law with n other than unity. This apparatus could work as a molecular pump with no moving parts.
Partial Dynamical Symmetry as an Intermediate Symmetry Structure
Leviatan, A
2003-01-01
We introduce the notion of a partial dynamical symmetry for which a prescribed symmetry is neither exact nor completely broken. We survey the different types of partial dynamical symmetries and present empirical examples in each category.
Designing Reflection and Symmetry Learning by Using Math Traditional Dance in Primary School
Directory of Open Access Journals (Sweden)
Yullys Helsa
2011-01-01
Full Text Available The innovation of education is an important point of Pendidikan Matematika Realistik Indonesia (PMRI, one of them through traditional dance as a context of national cultural. Dance that collaborated with concept of mathematics, it is called Math Traditional Dance. This research aims to produce learning line (specific the material of reflection and symmetry. The research method used is design research that consisted of preparing for the experiments, teaching experiments, and retrospective analysis. Data collected through observation, interviews, documentation and field notes. This research was conducted with 22 students in MIN 2 Palembang. From the try out that is obtained from the formal to the informal learning described in the learning process, so that support learning process of mirroring and symmetry for the students in grade four in elementary school.Key words: PMRI, math traditional dance, design research, learning path, mirroring and symmetry DOI: http://dx.doi.org/10.22342/jme.2.1.782.79-94
Endlich, Solomon; Penco, Riccardo
2013-01-01
The Galilei group involves mass as a central charge. We show that the associated superselection rule is incompatible with the observed phenomenology of superfluid helium 4: this is recovered only under the assumption that mass is spontaneously broken. This remark is somewhat immaterial for the real world, where the correct space-time symmetries are encoded by the Poincar\\'e group, which has no central charge. Yet it provides an explicit example of how superselection rules can be experimentally tested. We elaborate on what conditions must be met for our ideas to be generalizable to the relativistic case of the integer/half-integer angular momentum superselection rule.
Energy Technology Data Exchange (ETDEWEB)
Henley, E.M.
1981-09-01
Internal and space-time symmetries are discussed in this group of lectures. The first of the lectures deals with an internal symmetry, or rather two related symmetries called charge independence and charge symmetry. The next two discuss space-time symmetries which also hold approximately, but are broken only by the weak forces; that is, these symmetries hold for both the hadronic and electromagnetic forces. (GHT)
On reflection symmetry and its application to the Euler-Lagrange equations in fractional mechanics.
Klimek, Małgorzata
2013-05-13
We study the properties of fractional differentiation with respect to the reflection symmetry in a finite interval. The representation and integration formulae are derived for symmetric and anti-symmetric fractional derivatives, both of the Riemann-Liouville and Caputo type. The action dependent on the left-sided Caputo derivatives of orders in the range (1,2) is considered and we derive the Euler-Lagrange equations for the symmetric and anti-symmetric part of the trajectory. The procedure is illustrated with an example of the action dependent linearly on fractional velocities. For the obtained Euler-Lagrange system, we discuss its localization resulting from the subsequent symmetrization of the action.
Shirkov, Dmitrii V.
2009-06-01
This is a retrospective historical review of the ideas that led to the concept of the spontaneous symmetry breaking (SSB), the issue that has been implemented in quantum field theory in the form of the Higgs mechanism. The key stages covered include: the Bogoliubov microscopic theory of superfluidity (1946); the Bardeen-Cooper-Schrieffer-Bogoliubov microscopic theory of superconductivity (1957); superconductivity as superfluidity of Cooper pairs (Bogoliubov, 1958); the extension of the SSB concept to simple quantum field models (early 1960s); triumph of the Higgs model in electroweak theory (early 1980s). The role and status of the Higgs mechanism in the current Standard Model are discussed.
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Arakawa, Naoya
2016-11-01
I propose the emergence of the spin-orbital-coupled vector chirality in a nonfrustrated Mott insulator with the strong spin-orbit coupling due to a b -plane's inversion-symmetry (IS) breaking. I derive the superexchange interactions for a t2 g-orbital Hubbard model on a square lattice with the strong spin-orbit coupling and the IS-breaking-induced hopping integrals, and explain the microscopic origins of the Dzyaloshinsky-Moriya (DM) -type and the Kitaev-type interactions. Then, by adopting the mean-field approximation to a minimal model including only the Heisenberg-type and the DM-type nearest-neighbor interactions, I show that the IS breaking causes the spin-orbital-coupled chirality as a result of stabilizing the screw state. I also highlight the limit of the hard-pseudospin approximation in discussing the stability of the screw states in the presence of both the DM-type and the Kitaev-type interactions, and discuss its meaning. I finally discuss the effects of tetragonal crystal field and Jeff=3/2 states, and the application to the iridates near the [001 ] surface of Sr2IrO4 and the interface between Sr2IrO4 and Sr3Ir2O7 .
Energy Technology Data Exchange (ETDEWEB)
Yerin, Yuriy; Omelyanchouk, Alexander [Verkin Inst. for Low Temperature Physics and Engineering. 61103 Kharkiv (Ukraine); Drechsler, Stefan-Ludwig; Brink, Jeroen van den; Efremov, Dmitriy [Inst. for Theorretical Solid State Physics at the Leibniz Inst. for Solid State an Materials Research, IFW-Dresden, D-01171 Dresden (Germany)
2016-07-01
Within the Ginzburg-Landau formalism we provide a classification of all possible ground states (GS) of a three-band superconductor (3BSC) where either frustrated states with BTRS or a single non-BTRS GS with unconventional/conventional s-wave symmetry, respectively, exist. The necessary condition for a BTRS GS in general cannot be reduced to a ''-''sign of the product of all interband couplings (IBC) valid in the case of 3 equivalent bands with repulsive equal IBC, only. It corresponds to a maximal IBC frustration. We show that with increasing diversity of the parameter space this frustration is reduced and the regions of possible BTRS GS start to shrink. We track possible evolutions of a BTRS GS of a 3BSC based doubly-connected system in an external magnetic field. Depending on its parameters, a magnetic flux can induce various current density leaps, connected with adiabatic or non-adiabatic transitions from BTRS to non-BTRS states and vice versa. The current induced magnetic flux response of samples with a doubly-connected geometry e.g. as a thin tube provides a suitable experimental tool for the detection of BTRS GS.
Non-vanishing U{sub e3} and cos2{theta}{sub 23} from a broken Z{sub 2} symmetry
Energy Technology Data Exchange (ETDEWEB)
Grimus, Walter [Institut fuer Theoretische Physik, Universitaet Wien, Boltzmanngasse 5, A-1090 Vienna (Austria)]. E-mail: walter.grimus@univie.ac.at; Joshipura, Anjan S. [Physical Research Laboratory, Ahmedabad 380009 (India)]. E-mail: anjan@prl.ernet.in; Kaneko, Satoru [Department of Physics, Ochanomizu University, Tokyo 112-8610 (Japan)]. E-mail: satoru@phys.ocha.ac.jp; Lavoura, Luis [Instituto Superior Tecnico, Universidade Tecnica de Lisboa, P-1049-001 Lisbon (Portugal)]. E-mail: balio@cftp.ist.utl.pt; Sawanaka, Hideyuki [Graduate School of Science and Technology, Niigata University, 950-2181 Niigata (Japan)]. E-mail: hide@muse.sc.niigata-u.ac.jp; Tanimoto, Morimitsu [Department of Physics, Niigata University, 950-2181 Niigata (Japan)]. E-mail: tanimoto@muse.sc.niigata-u.ac.jp
2005-05-02
It is shown that the neutrino mass matrices in the flavour basis yielding a vanishing U{sub e3} are characterized by invariance under a class of Z{sub 2} symmetries. A specific Z{sub 2} in this class also leads to a maximal atmospheric mixing angle {theta}{sub 23}. The breaking of that Z{sub 2} can be parameterized by two dimensionless quantities, {epsilon} and {epsilon}{sup '}; the effects of {epsilon},{epsilon}{sup '}<>0 are studied perturbatively and numerically. The induced value of vertical bar U{sub e3} vertical bar strongly depends on the neutrino mass hierarchy. We find that vertical bar U{sub e3} vertical bar is less than 0.07 for a normal mass hierarchy, even when {epsilon},{epsilon}{sup '}{approx}30%. For an inverted mass hierarchy vertical bar U{sub e3} vertical bar tends to be around 0.1 but can be as large as 0.17. In the case of quasi-degenerate neutrinos, vertical bar U{sub e3} vertical bar could be close to its experimental upper bound 0.2. In contrast, vertical bar cos2{theta}{sub 23} vertical bar can always reach its experimental upper bound 0.28. We propose a specific model, based on electroweak radiative corrections in the MSSM, for {epsilon} and {epsilon}{sup '}. In that model, both vertical bar U{sub e3} vertical bar and vertical bar cos2{theta}{sub 23} vertical bar, could be close to their respective experimental upper bounds if neutrinos are quasi-degenerate.
Reflections on the four facets of symmetry: how physics exemplifies rational thinking
Mouchet, Amaury
2011-01-01
In contemporary theoretical physics, the powerful notion of symmetry stands for a web of intricate meanings among which I identify four clusters associated with the notion of transformation, comprehension, invariance and projection. While their interrelations are examined closely, these four facets of symmetry are scrutinised one after the other in great detail. This decomposition allows us to examine closely the multiple different roles symmetry plays in many places in physics. Furthermore, some connections with others disciplines like neurobiology, epistemology, cognitive sciences and, not least, philosophy are proposed in an attempt to show that symmetry can be an organising principle also in these fields.
Reflection symmetry at a B=0 metal-insulator transition in two dimensions
Simonian, D.; Kravchenko, S. V.; Sarachik, M. P.
1996-01-01
We report a remarkable symmetry between the resistivity and conductivity on opposite sides of the B=0 metal-insulator transition in a two-dimensional electron gas in high-mobility silicon MOSFET's. This symmetry implies that the transport mechanisms on the two sides are related.
The Parallel Implementation of Algorithms for Finding the Reflection Symmetry of the Binary Images
Fedotova, S.; Seredin, O.; Kushnir, O.
2017-05-01
In this paper, we investigate the exact method of searching an axis of binary image symmetry, based on brute-force search among all potential symmetry axes. As a measure of symmetry, we use the set-theoretic Jaccard similarity applied to two subsets of pixels of the image which is divided by some axis. Brute-force search algorithm definitely finds the axis of approximate symmetry which could be considered as ground-truth, but it requires quite a lot of time to process each image. As a first step of our contribution we develop the parallel version of the brute-force algorithm. It allows us to process large image databases and obtain the desired axis of approximate symmetry for each shape in database. Experimental studies implemented on "Butterflies" and "Flavia" datasets have shown that the proposed algorithm takes several minutes per image to find a symmetry axis. However, in case of real-world applications we need computational efficiency which allows solving the task of symmetry axis search in real or quasi-real time. So, for the task of fast shape symmetry calculation on the common multicore PC we elaborated another parallel program, which based on the procedure suggested before in (Fedotova, 2016). That method takes as an initial axis the axis obtained by superfast comparison of two skeleton primitive sub-chains. This process takes about 0.5 sec on the common PC, it is considerably faster than any of the optimized brute-force methods including ones implemented in supercomputer. In our experiments for 70 percent of cases the found axis coincides with the ground-truth one absolutely, and for the rest of cases it is very close to the ground-truth.
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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.
Modified Friedberg-Lee symmetry for neutrino mixing
Zhao, Zhen-hua
2015-12-01
In this paper, we put forward a special neutrino mass matrix which is invariant under a modified Friedberg-Lee (FL) transformation νe→νe-2 ξ and νμ ,τ→νμ ,τ+ξ with ξ being a space-time independent element of the Grassmann algebra. Compared to the original FL symmetry (with the transformation νe ,μ ,τ→νe ,μ ,τ+ξ ) which results in the TM2 neutrino mixing, the modified FL symmetry will lead us to the TM1 mixing which has a better agreement with the experimental results. While the original FL symmetry has to be broken in order to produce a realistic neutrino mass spectrum, the modified FL symmetry is allowed to remain intact and give us a vanishing m1. A combination of the FL symmetry with the μ -τ reflection symmetry is also discussed.
Han Du, Wen-Ge; Götz, Andreas W; Yang, Longhua; Walker, Ross C; Noodleman, Louis
2016-08-21
Broken-symmetry density functional calculations have been performed on the [Fea3, CuB] dinuclear center (DNC) of ba3 cytochrome c oxidase from Thermus thermophilus in the states of [Fea3(3+)-(HO2)(-)-CuB(2+), Tyr237(-)] and [Fea3(4+)[double bond, length as m-dash]O(2-), OH(-)-CuB(2+), Tyr237˙], using both PW91-D3 and OLYP-D3 functionals. Tyr237 is a special tyrosine cross-linked to His233, a ligand of CuB. The calculations have shown that the DNC in these states strongly favors the protonation of His376, which is above propionate-A, but not of the carboxylate group of propionate-A. The energies of the structures obtained by constrained geometry optimizations along the O-O bond cleavage pathway between [Fea3(3+)-(O-OH)(-)-CuB(2+), Tyr237(-)] and [Fea3(4+)[double bond, length as m-dash]O(2-)HO(-)-CuB(2+), Tyr237˙] have also been calculated. The transition of [Fea3(3+)-(O-OH)(-)-CuB(2+), Tyr237(-)] → [Fea3(4+)[double bond, length as m-dash]O(2-)HO(-)-CuB(2+), Tyr237˙] shows a very small barrier, which is less than 3.0/2.0 kcal mol(-1) in PW91-D3/OLYP-D3 calculations. The protonation state of His376 does not affect this O-O cleavage barrier. The rate limiting step of the transition from state A (in which O2 binds to Fea3(2+)) to state PM ([Fea3(4+)[double bond, length as m-dash]O(2-), OH(-)-CuB(2+), Tyr237˙], where the O-O bond is cleaved) in the catalytic cycle is, therefore, the proton transfer originating from Tyr237 to O-O to form the hydroperoxo [Fea3(3+)-(O-OH)(-)-CuB(2+), Tyr237(-)] state. The importance of His376 in proton uptake and the function of propionate-A/neutral-Asp372 as a gate to prevent the proton from back-flowing to the DNC are also shown.
Reflection Positivity of ${\\cal N}=1$ Wess-Zumino model on the lattice with exact U(1)$_R$ symmetry
Kikukawa, Yoshio
2010-01-01
By using overlap Majorana fermions, the ${\\cal N}=1$ chiral multiple can be formulated so that the supersymmetry is manifest and the vacuum energy is cancelled in the free limit, thanks to the bilinear nature of the free action. It is pointed out, however, that in this formulation the reflection positivity is violated in the bosonic part of the action, although it is satisfied in the fermionic part. It is found that the positivity of the spectral density of the bosonic two-point correlation function is ensured only for the spacial momenta $a | p_k | \\lesssim 1.72$ $(k=1,2,3)$. It is then argued that in formulating ${\\cal N}=1$ Wess-Zumino model with the overlap Majorana fermion, one may adopt a simpler nearest-neighbor bosonic action, discarding the free limit manifest supersymmetry. The model still preserves the would-be U(1)$_R$ symmetry and satisfies the reflection positivity.
Institute of Scientific and Technical Information of China (English)
XU Fangqian; HE Shitang
2005-01-01
The closed-form expressions on strip reflection coefficients of tetragonal 4/mmm,hexagonal 6/mm and trigonal 3m crystal, etc, were derived, which are different from that of cubic m3m crystal published. The reflection coefficients of short-circuited Al grating and groove grating on 112° rotated X-cut Y-propagation LiTaO3 are then given. The reflection property of a short-circuited Al -recessed groove grating on 112°LiTaO3 has been experimentally studied and the condition without internal reflection was achieved. It concludes that the structure of single finger without internal reflection can be realized by the short-circuited Al -recessed groove grating on 112°LiTaO3 and thereafter a pass-band filter with central frequency at 255 MHz,bandwidth about 10 MHz, pass-band ripples less than 0.4 dB was yielded.
Spontaneous breaking of discrete symmetries in QCD on a small volume
Lucini, Biagio; Pica, Claudio
2007-01-01
In a compact space with non-trivial cycles, for sufficiently small values of the compact dimensions, charge conjugation (C), spatial reflection (P) and time reversal (T) are spontaneously broken in QCD. The order parameter for the symmetry breaking is the trace of the Wilson line wrapping around the compact dimension, which acquires an imaginary part in the broken phase. We show that a physical signature for the symmetry breaking is a persistent baryonic current wrapping in the compact directions. The existence of such a current is derived analytically at first order in perturbation theory and confirmed in the non-perturbative regime by lattice simulations.
Softly Broken Supersymmetric Gauge Theories through Compactifications
Takenaga, K
1998-01-01
Effects of boundary conditions of fields for compactified space directions on the supersymmetric gauge theories are discussed. For general and possible boundary conditions the supersymmetry is explicitly broken to yield universal soft supersymmetry breaking terms, and the gauge symmetry of the theory can also be broken through the dynamics of non-integrable phases, depending on number and the representation under the gauge group of matters. The 4-dimensional supersymmetric QCD is studied as a toy model when one of the space coordinates is compactified on $S^1$.
Reflection K-matrices for a nineteen vertex model with Uq [ osp (2 | 2) (2) ] symmetry
Vieira, R. S.; Lima Santos, A.
2017-09-01
We derive the solutions of the boundary Yang-Baxter equation associated with a supersymmetric nineteen vertex model constructed from the three-dimensional representation of the twisted quantum affine Lie superalgebra Uq [ osp (2 | 2) (2) ]. We found three classes of solutions. The type I solution is characterized by three boundary free-parameters and all elements of the corresponding reflection K-matrix are different from zero. In the type II solution, the reflection K-matrix is even (every element of the K-matrix with an odd parity is null) and it has only one boundary free-parameter. Finally, the type III solution corresponds to a diagonal reflection K-matrix with two boundary free-parameters.
Hak, David J; McElvany, Matthew
2008-02-01
Despite advances in metallurgy, fatigue failure of hardware is common when a fracture fails to heal. Revision procedures can be difficult, usually requiring removal of intact or broken hardware. Several different methods may need to be attempted to successfully remove intact or broken hardware. Broken intramedullary nail cross-locking screws may be advanced out by impacting with a Steinmann pin. Broken open-section (Küntscher type) intramedullary nails may be removed using a hook. Closed-section cannulated intramedullary nails require additional techniques, such as the use of guidewires or commercially available extraction tools. Removal of broken solid nails requires use of a commercial ratchet grip extractor or a bone window to directly impact the broken segment. Screw extractors, trephines, and extraction bolts are useful for removing stripped or broken screws. Cold-welded screws and plates can complicate removal of locked implants and require the use of carbide drills or high-speed metal cutting tools. Hardware removal can be a time-consuming process, and no single technique is uniformly successful.
Symmetries of hadrons after unbreaking the chiral symmetry
Glozman, L Ya; Schröck, M
2012-01-01
We study hadron correlators upon artificial restoration of the spontaneously broken chiral symmetry. In a dynamical lattice simulation we remove the lowest lying eigenmodes of the Dirac operator from the valence quark propagators and study evolution of the hadron masses obtained. All mesons and baryons in our study, except for a pion, survive unbreaking the chiral symmetry and their exponential decay signals become essentially better. From the analysis of the observed spectroscopic patterns we conclude that confinement still persists while the chiral symmetry is restored. All hadrons fall into different chiral multiplets. The broken U(1)_A symmetry does not get restored upon unbreaking the chiral symmetry. We also observe signals of some higher symmetry that includes chiral symmetry as a subgroup. Finally, from comparison of the \\Delta - N splitting before and after unbreaking of the chiral symmetry we conclude that both the color-magnetic and the flavor-spin quark-quark interactions are of equal importance.
Evidence of Broken Reciprocity in Chiral Liquid Crystals
Moreira, Michele; Venkataraman, Nithya; Taheri, Bahman; Palffy-Muhoray, Peter
2008-03-01
Reciprocity in light scattering is predicated on bounded scattering media with symmetric and linear permittivity, conductivity and permeability. Due to their anisotropy and chirality, cholesteric liquid crystal form periodic dielectric structures. If the periodicity is comparable to the wavelength of light, these phases are self-assembled photonic band gap structures. There appear in the permittivity odd powers of the wave vector resulting from nonlocality and broken inversion symmetry. Evidence of non-reciprocity has been found in optically active crystals by Bennett [1] and in stacks of cholesteric and nematic liquid crystal cells by Takezoe [2]. We present experimental data showing broken reciprocity in transmittance and reflectance in cholesteric cells with different pitches having overlapping but distinct reflection bands. We explain our results in terms of simple analytic descriptions of material properties and propagating modes. [1] P.J. Bennett, S. Dhanjal, Yu. P. Svirko and N. I. Zheludev, Opt. Lett. 21, 1955 (1996) [2] J. Hwang; M.H. Song; B. Park; S. Nishimura; T. Toyooka; J.W. Wu; Y. Takanishi; K. Ishikawa; H. Takezoe, Nat. Mat. 4, 383 (2005).
Kreshchuk, Michael
2016-01-01
The phenomenon of duality reflects a link between the behaviour of a system in different regimes. The goal of this work is to expose the classical origins of such links, and to demonstrate how they come to life in some quasi-exactly solvable problems of quantum mechanics. By studying the global properties of the Riemannian surface of the classical momentum, we reveal that the abbreviated classical action possesses a symmetry which holds also at the quantum level and underlies the energy reflection symmetry of the quantum energy levels.
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 ...
Directory of Open Access Journals (Sweden)
METODIJA NAJDOSKI
2000-07-01
Full Text Available Fourier-transform infrared (FT-IR reflection spectra, asquired at nearnormal incidence, were recorded from single crystals belonging to six crystal systems: CsCr(SO42.12H2O (alum, cubic, K2CuCl2·2H2O (Mitscherlichite, tetragonal, CaCO3 (calcite, hexagonal, KHSO4 (mercallite, orthorhombic, CaSO4·2H2O (gypsum, monoclinic and CuSO4·5H2O (chalcantite, triclinic. The acquired IR reflection spectra were further transformed into absorption spectra, employing the Kramers-Kronig transformation. Except for the cubic alums, the spectra strongly depend on the crystal face from which they were recorded; this is a consequence of anisotropy. Phonons of a given symmetry (E-species, in tetragonal/hexagonal and B-species, in monoclinic crystals may be resolved without using a polariser. The spectrum may be simplified in the case of an orthorhombic crystal, as well. The longitudinal-optical (LO and transversal-optical (TO mode frequencies were calculated in the case of optically isotropic and the simplified spectra of optically uniaxial crystals.
Voisin, Claire
1999-01-01
This is the English translation of Professor Voisin's book reflecting the discovery of the mirror symmetry phenomenon. The first chapter is devoted to the geometry of Calabi-Yau manifolds, and the second describes, as motivation, the ideas from quantum field theory that led to the discovery of mirror symmetry. The other chapters deal with more specialized aspects of the subject: the work of Candelas, de la Ossa, Greene, and Parkes, based on the fact that under the mirror symmetry hypothesis, the variation of Hodge structure of a Calabi-Yau threefold determines the Gromov-Witten invariants of its mirror; Batyrev's construction, which exhibits the mirror symmetry phenomenon between hypersurfaces of toric Fano varieties, after a combinatorial classification of the latter; the mathematical construction of the Gromov-Witten potential, and the proof of its crucial property (that it satisfies the WDVV equation), which makes it possible to construct a flat connection underlying a variation of Hodge structure in the ...
Zero index metamaterials with PT symmetry in a waveguide system.
Fu, Yangyang; Xu, Yadong; Chen, Huanyang
2016-01-25
Inspired by the concept of parity-time symmetry, we propose a new waveguide system consisting of zero index metamaterials with an air gap. Based on analytical calculations and numerical simulations, we demonstrate that there are two exceptional points in such a system, which can induce unidirectional transparency. However, the introduced air gap could effectively manipulate the property of the waveguide system with PT symmetry. In particular, coherent perfect absorber-laser modes could be excited in PT broken phase, if a specific phase difference in the air gap is obtained. More interestingly, when Fabry-Pérot resonances take place in the air gap, the PT symmetry property will be suppressed, i.e., the value of loss/gain could not affect transmission and reflection of the waveguide. As a result, perfect bidirectional transmission without reflection can occur in the waveguide system.
Gauge symmetry enhancement in Hamiltonian formalism
Hong, S T; Lee, T H; Oh, P; Oh, Phillial
2003-01-01
We study the Hamiltonian structure of the gauge symmetry enhancement in the enlarged CP(N) model coupled with U(2) chern-Simons term, which contains a free parameter governing explicit symmetry breaking and symmetry enhancement. After giving a general discussion of the geometry of constrained phase space suitable for the symmetry enhancement, we explicitly perform the Dirac analysis of out model and compute the Dirac brackets for the symmetry enhanced and broken cases. We also discuss some related issues.
Exact Dynamical and Partial Symmetries
Leviatan, A
2010-01-01
We discuss a hierarchy of broken symmetries with special emphasis on partial dynamical symmetries (PDS). The latter correspond to a situation in which a non-invariant Hamiltonian accommodates a subset of solvable eigenstates with good symmetry, while other eigenstates are mixed. We present an algorithm for constructing Hamiltonians with this property and demonstrate the relevance of the PDS notion to nuclear spectroscopy, to quantum phase transitions and to mixed systems with coexisting regularity and chaos.
Exact dynamical and partial symmetries
Energy Technology Data Exchange (ETDEWEB)
Leviatan, A, E-mail: ami@phys.huji.ac.il [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel)
2011-03-01
We discuss a hierarchy of broken symmetries with special emphasis on partial dynamical symmetries (PDS). The latter correspond to a situation in which a non-invariant Hamiltonian accommodates a subset of solvable eigenstates with good symmetry, while other eigenstates are mixed. We present an algorithm for constructing Hamiltonians with this property and demonstrate the relevance of the PDS notion to nuclear spectroscopy, to quantum phase transitions and to mixed systems with coexisting regularity and chaos.
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 ...
Nicolis, Alberto
2011-01-01
For relativistic quantum field theories, we consider Lorentz breaking, spatially homogeneous field configurations or states that evolve in time along a symmetry direction. We dub this situation "spontaneous symmetry probing" (SSP). We mainly focus on internal symmetries, i.e. on symmetries that commute with the Poincare group. We prove that the fluctuations around SSP states have a Lagrangian that is explicitly time independent, and we provide the field space parameterization that makes this manifest. We show that there is always a gapless Goldstone excitation that perturbs the system in the direction of motion in field space. Perhaps more interestingly, we show that if such a direction is part of a non-Abelian group of symmetries, the Goldstone bosons associated with spontaneously broken generators that do not commute with the SSP one acquire a gap, proportional to the SSP state's "speed". We outline possible applications of this formalism to inflationary cosmology.
Baryon currents in the C-broken phase of QCD
Lucini, B; Pica, C
2007-01-01
In a space with some sufficiently small compact dimension (with non-trivial cycles) and with periodic boundary conditions for the fermions, the charge conjugation (C), spatial parity (P), time reversal (T) and CPT symmetries are spontaneously broken in QCD. We have investigated what are the physical consequences of the breaking of these discrete symmetries, that is what local observables can be used to detect it. We show that the breaking induces the generation of baryon currents, propagating along the compact dimensions.
Evidence of Broken Reciprocity in Cholesteric Liquid Crystals
Venkataraman, Nithya; Moreira, Michele; Taheri, Bahman; Palffy-Muhoray, Peter
2007-03-01
Reciprocity of scattering of a plane incident wave is predicated on bounded scattering media with symmetric and linear permittivity, conductivity and permeability. In chiral media, such as cholesteric liquid crystals, the dielectric tensor is asymmetric due the presence of odd powers of the wave vector resulting from nonlocality and broken inversion symmetry. Evidence of non-reciprocity has been found in optically active crystals by Bennet [1] and in stacks of cholesteric and nematic liquid crystal cells [2]. Here we present transmittance and reflectance data for cholesteric cells with different pitches having overlapping but distinct reflection bands. We relate our results to simple analytic descriptions of the materials properties and of propagating modes and assess them in light of the requirements for reciprocity. 1. P.J. Bennett, S. Dhanjal, Yu. P. Svirko and N. I. Zheludev, Opt. Lett. 21, 1955 (1996) 2. J. Hwang; M.H. Song; B. Park; S. Nishimura; T. Toyooka; J.W. Wu; Y. Takanishi; K. Ishikawa; H. Takezoe, Nat. Mat. 4, 383 (2005).
Broken current anomalous dimensions, conformal manifolds and RG flows
Bashmakov, Vladimir; Raj, Himanshu
2016-01-01
We consider deformations of a conformal field theory explicitly breaking some global symmetries of the theory, addressing both cases of marginal and relevant deformations. Exploiting the constraints put by conformal symmetry, we compute anomalous dimensions of broken currents. Our analysis is done using field theory techniques and also holographic ones, where necessary. Field theoretical methods suffice to discuss e.g. symmetry-breaking deformations of the $O(N )$ model in $d=4-\\epsilon$ dimensions. Holography is instrumental, instead, to compute current anomalous dimensions in $\\beta$-deformed superconformal field theories, and in a class of $N = 1$ RG flows at large 't Hooft coupling.
Institute of Scientific and Technical Information of China (English)
Adi Shamir
2009-01-01
@@ It's all us pleasure to come to China.a great deal of cheerful times already.I hope that we have additional opportunity to meet,talk about cryptography and other components.Today I am going to give a general talk which is not designed for special lists,about how could the systems get broken like this.I think I don't assume you know much about cryptography and some of the basics.Cryptography deals with issue how to send secret information from a sender which is usually called Alice.to a receiver which is usually called Bob.The usual way how to encrypt data is to use an encryption box that accepts the plaintext,the plaintext is the message that you would like to send encrypted.It could be just"Good morning".By using a secret cryptographic key K,you put ciphertext which looks very very strange."zqvkj…".
Nonreciprocity in giant Goos-H\\"anchen shift due to symmetry breaking
Kumari, Madhuri
2011-01-01
We study giant Goos-H\\"anchen (GH) shift in reflection from a near-symmetric coupled waveguide structure. We show that broken spatial symmetry can lead to GH shift with different signs for illumination from the opposite ends, a direct consequence of the nonreciprocity relations considered earlier (Opt. Lett. 27,1205 (2002)). Symmetry breaking by adding a few nm thick bio-layer to one of the guides is enough to observe the nonreciprocity. This may have far reaching implications for efficient biosensing.
The affordances of broken affordances
DEFF Research Database (Denmark)
Grünbaum, Martin Gielsgaard; Simonsen, Jakob Grue
2015-01-01
important: how users may (i) achieve their goals in the presence of such broken affordances, and may (ii) repurpose or otherwise interact with artefacts with broken affordances. We argue that (A) thorough analyses of breakdowns of affordances and their associated signifiers and feedbacks have implication...
Broken Bones, Sprains, and Strains (For Parents)
... Feeding Your 1- to 2-Year-Old Broken Bones, Sprains, and Strains KidsHealth > For Parents > Broken Bones, ... home. What to Do: For a Suspected Broken Bone: Do not move a child whose injury involves ...
Fractured toe - self-care; Broken bone - toe - self-care; Fracture - toe - self-care; Fracture phalanx - toe ... often treated without surgery and can be taken care of at home. Severe injuries include: Breaks that ...
Femur Shaft Fractures (Broken Thighbone)
... going, whether you were the driver or a passenger, whether you were wearing your seat belt, and ... are sometimes treated with a cast. For more information on that, ... is a pulley system of weights and counterweights that holds the broken ...
Distal Radius Fracture (Broken Wrist)
.org Distal Radius Fracture (Broken Wrist) Page ( 1 ) The radius is the larger of the two bones of the forearm. The ... the distal end. A fracture of the distal radius occurs when the area of the radius near ...
METODIJA NAJDOSKI; VLADIMIR IVANOVSKI; VLADIMIR M. PETRUSEVSKI
2000-01-01
Fourier-transform infrared (FT-IR) reflection spectra, asquired at nearnormal incidence, were recorded from single crystals belonging to six crystal systems: CsCr(SO4)2.12H2O (alum, cubic), K2CuCl2·2H2O (Mitscherlichite, tetragonal), CaCO3 (calcite, hexagonal), KHSO4 (mercallite, orthorhombic), CaSO4·2H2O (gypsum, monoclinic) and CuSO4·5H2O (chalcantite, triclinic). The acquired IR reflection spectra were further transformed into absorption spectra, employing the Kramers-Kronig transformation...
Job loss and broken partnerships
DEFF Research Database (Denmark)
Kriegbaum, Margit; Christensen, Ulla; Lund, Rikke;
2008-01-01
The aim of this study was to investigate the effects of the accumulated number of job losses and broken partnerships (defined as the end of cohabitation) on the risk of fatal and nonfatal events of ischemic heart disease (IHD).......The aim of this study was to investigate the effects of the accumulated number of job losses and broken partnerships (defined as the end of cohabitation) on the risk of fatal and nonfatal events of ischemic heart disease (IHD)....
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.)
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.
Financial symmetry and moods in the market.
Savona, Roberto; Soumare, Maxence; Andersen, Jørgen Vitting
2015-01-01
This paper studies how certain speculative transitions in financial markets can be ascribed to a symmetry break that happens in the collective decision making. Investors are assumed to be bounded rational, using a limited set of information including past price history and expectation on future dividends. Investment strategies are dynamically changed based on realized returns within a game theoretical scheme with Nash equilibria. In such a setting, markets behave as complex systems whose payoff reflect an intrinsic financial symmetry that guarantees equilibrium in price dynamics (fundamentalist state) until the symmetry is broken leading to bubble or anti-bubble scenarios (speculative state). We model such two-phase transition in a micro-to-macro scheme through a Ginzburg-Landau-based power expansion leading to a market temperature parameter which modulates the state transitions in the market. Via simulations we prove that transitions in the market price dynamics can be phenomenologically explained by the number of traders, the number of strategies and amount of information used by agents, all included in our market temperature parameter.
Financial Symmetry and Moods in the Market
Savona, Roberto; Soumare, Maxence; Andersen, Jørgen Vitting
2015-01-01
This paper studies how certain speculative transitions in financial markets can be ascribed to a symmetry break that happens in the collective decision making. Investors are assumed to be bounded rational, using a limited set of information including past price history and expectation on future dividends. Investment strategies are dynamically changed based on realized returns within a game theoretical scheme with Nash equilibria. In such a setting, markets behave as complex systems whose payoff reflect an intrinsic financial symmetry that guarantees equilibrium in price dynamics (fundamentalist state) until the symmetry is broken leading to bubble or anti-bubble scenarios (speculative state). We model such two-phase transition in a micro-to-macro scheme through a Ginzburg-Landau-based power expansion leading to a market temperature parameter which modulates the state transitions in the market. Via simulations we prove that transitions in the market price dynamics can be phenomenologically explained by the number of traders, the number of strategies and amount of information used by agents, all included in our market temperature parameter. PMID:25856392
Financial symmetry and moods in the market.
Directory of Open Access Journals (Sweden)
Roberto Savona
Full Text Available This paper studies how certain speculative transitions in financial markets can be ascribed to a symmetry break that happens in the collective decision making. Investors are assumed to be bounded rational, using a limited set of information including past price history and expectation on future dividends. Investment strategies are dynamically changed based on realized returns within a game theoretical scheme with Nash equilibria. In such a setting, markets behave as complex systems whose payoff reflect an intrinsic financial symmetry that guarantees equilibrium in price dynamics (fundamentalist state until the symmetry is broken leading to bubble or anti-bubble scenarios (speculative state. We model such two-phase transition in a micro-to-macro scheme through a Ginzburg-Landau-based power expansion leading to a market temperature parameter which modulates the state transitions in the market. Via simulations we prove that transitions in the market price dynamics can be phenomenologically explained by the number of traders, the number of strategies and amount of information used by agents, all included in our market temperature parameter.
Automatic CP invariance and flavor symmetry
Dutta, G; Dutta, Gautam; Joshipura, Anjan S
1996-01-01
The approximate conservation of CP can be naturally understood if it arises as an automatic symmetry of the renormalizable Lagrangian. We present a specific realistic example with this feature. In this example, the global Peccei-Quinn symmetry and gauge symmetries of the model make the renormalizable Lagrangian CP invariant but allow non zero hierarchical masses and mixing among the three generations. The left-right and a horizontal U(1)_H symmetry is imposed to achieve this. The non-renormalizable interactions invariant under these symmetries violate CP whose magnitude can be in the experimentally required range if U(1)_H is broken at very high, typically, near the grand unification scale.
Inverse Symmetry Breaking and the Exact Renormalization Group
Pietroni, M; Tetradis, N
1997-01-01
We discuss the question of inverse symmetry breaking at non-zero temperature using the exact renormalization group. We study a two-scalar theory and concentrate on the nature of the phase transition during which the symmetry is broken. We also examine the persistence of symmetry breaking at temperatures higher than the critical one.
Leptonic Dirac CP Violation Predictions from Residual Discrete Symmetries
Girardi, I; Stuart, Alexander J; Titov, A V
2016-01-01
Assuming that the observed pattern of 3-neutrino mixing is related to the existence of a (lepton) flavour symmetry, corresponding to a non-Abelian discrete symmetry group $G_f$, and that $G_f$ is broken to specific residual symmetries $G_e$ and $G_\
Institute of Scientific and Technical Information of China (English)
YANG Zhiyuan; ZHOU Anning
2005-01-01
The characteristics of broken surfaces were researched by a scanning electron microscope (SEM) and a reflection microscope, and the fractal dimensions of broken surfaces were measured by the Slit Island method. The experimental results indicate that the broken surface of aluminum electric porcelain is a fractal body in statistics, and the fractal dimensions of broken surfaces are different with the different amplification multiple value.In all of measured fractal dimensions,both of values measured in 100× under reflection microscope and in 500× under SEM are maximum, whereas the values measured in 63× under reflection microscope and in 2000× under SEM are obviously minimum. The fractal dimensions of broken surfaces are also affected by the degrees of gray comparison and the kinds of measuring methods. The relationships between the fractal dimensions of broken surfaces and porcelain bend strengths are that they are in positive correlation on the low multiples and in negative correlation on the high multiples.
Leptogenesis and residual CP symmetry
Energy Technology Data Exchange (ETDEWEB)
Chen, Peng; Ding, Gui-Jun [Department of Modern Physics, University of Science and Technology of China,Hefei, Anhui 230026 (China); King, Stephen F. [Physics and Astronomy, University of Southampton,Southampton, SO17 1BJ (United Kingdom)
2016-03-31
We discuss flavour dependent leptogenesis in the framework of lepton flavour models based on discrete flavour and CP symmetries applied to the type-I seesaw model. Working in the flavour basis, we analyse the case of two general residual CP symmetries in the neutrino sector, which corresponds to all possible semi-direct models based on a preserved Z{sub 2} in the neutrino sector, together with a CP symmetry, which constrains the PMNS matrix up to a single free parameter which may be fixed by the reactor angle. We systematically study and classify this case for all possible residual CP symmetries, and show that the R-matrix is tightly constrained up to a single free parameter, with only certain forms being consistent with successful leptogenesis, leading to possible connections between leptogenesis and PMNS parameters. The formalism is completely general in the sense that the two residual CP symmetries could result from any high energy discrete flavour theory which respects any CP symmetry. As a simple example, we apply the formalism to a high energy S{sub 4} flavour symmetry with a generalized CP symmetry, broken to two residual CP symmetries in the neutrino sector, recovering familiar results for PMNS predictions, together with new results for flavour dependent leptogenesis.
Weakly Nonlinear Theory of Pattern-Forming Systems with Spontaneously Broken Isotropy
Rossberg, A G; Kramer, L; Pesch, W
1996-01-01
Quasi two-dimensional pattern forming systems with spontaneously broken isotropy represent a novel symmetry class, that is experimentally accessible in electroconvection of homeotropically aligned liquid crystals. We present a weakly nonlinear analysis leading to amplitude equations which couple the short-wavelength patterning mode with the Goldstone mode resulting from the broken isotropy. The new coefficients in these equations are calculated from the hydrodynamics. Simulations exhibit a new type of spatio-temporal chaos at onset. The results are compared with experiments.
... having a heart attack , a more common medical emergency caused by a blocked coronary (heart) artery. The two conditions have similar symptoms, ... after exposure to the unexpected stress. Many seek emergency care, concerned they are having a heart attack. Often, patients who have broken heart syndrome ...
A light sterile neutrino from Friedberg–Lee symmetry
National Research Council Canada - National Science Library
He, Xiao-Gang; Liao, Wei
2014-01-01
.... In this article we show that such an eV scale light sterile neutrino candidate can be obtained in a seesaw model in which the right-handed neutrinos satisfy a softly-broken Friedberg-Lee (FL) symmetry...
Dispersionless and multicomponent BKP hierarchies with quantum torus symmetries
Li, Chuanzhong
2017-09-01
In this article, we will construct the additional perturbative quantum torus symmetry of the dispersionless BKP hierarchy based on the W∞ infinite dimensional Lie symmetry. These results show that the complete quantum torus symmetry is broken from the BKP hierarchy to its dispersionless hierarchies. Further a series of additional flows of the multicomponent BKP hierarchy will be defined and these flows constitute an N-folds direct product of the positive half of the quantum torus symmetries.
The Limits of Custodial Symmetry
Chivukula, R Sekhar; Foadi, Roshan; Simmons, Elizabeth H
2010-01-01
We introduce a toy model implementing the proposal of using a custodial symmetry to protect the Z b_L bbar_L coupling from large corrections. This "doublet-extended standard model" adds a weak doublet of fermions (including a heavy partner of the top quark) to the particle content of the standard model in order to implement an O(4) x U(1)_X = SU(2)_L x SU(2)_R x P_LR x U(1)_X symmetry in the top-quark mass generating sector. This symmetry is softly broken to the gauged SU(2)_L x U(1)_Y electroweak symmetry by a Dirac mass M for the new doublet; adjusting the value of M allows us to explore the range of possibilities between the O(4)-symmetric (M to 0) and standard-model-like (M to infinity) limits.
The Limits of Custodial Symmetry
Chivukula, R Sekhar; Foadi, Roshan; Simmons, Elizabeth H
2010-01-01
We introduce a toy model implementing the proposal of using a custodial symmetry to protect the Zbb coupling from large corrections. This "doublet-extended standard model" adds a weak doublet of fermions (including a heavy partner of the top quark) to the particle content of the standard model in order to implement an O(4) x U(1)_X = SU(2)_L x SU(2)_R x P_{LR} x U(1)_X symmetry that protects the Zbb coupling. This symmetry is softly broken to the gauged SU(2)_L x U(1)_Y electroweak symmetry by a Dirac mass M for the new doublet; adjusting the value of M allows us to explore the range of possibilities between the O(4)-symmetric (M to 0) and standard-model-like (M to infinity) limits.
Nucci, M. C.
2016-09-01
We review some of our recent work devoted to the problem of quantization with preservation of Noether symmetries, finding hidden linearity in superintegrable systems, and showing that nonlocal symmetries are in fact local. In particular, we derive the Schrödinger equation for the isochronous Calogero goldfish model using its relation to Darwin equation. We prove the linearity of a classical superintegrable system on a plane of nonconstant curvature. We find the Lie point symmetries that correspond to the nonlocal symmetries (also reinterpreted as λ-symmetries) of the Riccati chain.
Measuring Complexity through Average Symmetry
Alamino, Roberto C.
2015-01-01
This work introduces a complexity measure which addresses some conflicting issues between existing ones by using a new principle - measuring the average amount of symmetry broken by an object. It attributes low (although different) complexity to either deterministic or random homogeneous densities and higher complexity to the intermediate cases. This new measure is easily computable, breaks the coarse graining paradigm and can be straightforwardly generalised, including to continuous cases an...
Identical Wells, Symmetry Breaking, and the Near-Unitary Limit
Harshman, N. L.
2017-03-01
Energy level splitting from the unitary limit of contact interactions to the near unitary limit for a few identical atoms in an effectively one-dimensional well can be understood as an example of symmetry breaking. At the unitary limit in addition to particle permutation symmetry there is a larger symmetry corresponding to exchanging the N! possible orderings of N particles. In the near unitary limit, this larger symmetry is broken, and different shapes of traps break the symmetry to different degrees. This brief note exploits these symmetries to present a useful, geometric analogy with graph theory and build an algebraic framework for calculating energy splitting in the near unitary limit.
Tuning the cosmological constant, broken scale invariance, unitarity
Energy Technology Data Exchange (ETDEWEB)
Förste, Stefan; Manz, Paul [Bethe Center for Theoretical Physics,Nussallee 12, 53115 Bonn (Germany); Physikalisches Institut der Universität Bonn,Nussallee 12, 53115 Bonn (Germany)
2016-06-10
We study gravity coupled to a cosmological constant and a scale but not conformally invariant sector. In Minkowski vacuum, scale invariance is spontaneously broken. We consider small fluctuations around the Minkowski vacuum. At the linearised level we find that the trace of metric perturbations receives a positive or negative mass squared contribution. However, only for the Fierz-Pauli combination the theory is free of ghosts. The mass term for the trace of metric perturbations can be cancelled by explicitly breaking scale invariance. This reintroduces fine-tuning. Models based on four form field strength show similarities with explicit scale symmetry breaking due to quantisation conditions.
Bel, Bernard
2011-01-01
This “ritual of the broken stone” was performed in July 1996 to celebrate an auspicious event in a private house of Choglamsar, a settlement of Tibetan migrates in a suburb of Leh (Ladakh, India). According to local informants, its performers were ermits living in caves of Spiti. Most astonishing is the mixture of a religious ritual with comical scenes and demonstrations of 'magical' powers. Este “ritual de la piedra rota“ se llevó a cabo en julio de 1996 para celebrar un acontecimiento au...
On the origin of neutrino flavour symmetry
King, Stephen F
2009-01-01
We study classes of models which are based on some discrete family symmetry which is completely broken such that the observed neutrino flavour symmetry emerges indirectly as an accidental symmetry. For such "indirect" models we discuss the D-term flavon vacuum alignments which are required for such an accidental flavour symmetry consistent with tri-bimaximal lepton mixing to emerge. We identify large classes of suitable discrete family symmetries, namely the $\\Delta(3n^2)$ and $\\Delta(6n^2)$ groups, together with other examples such as $Z_7\\rtimes Z_3$. In such indirect models the implementation of the type I see-saw mechanism is straightforward using constrained sequential dominance. However the accidental neutrino flavour symmetry may be easily violated, for example leading to a large reactor angle, while maintaining accurately the tri-bimaximal solar and atmospheric predictions.
Classical Kinetic Theory of Landau Damping for Self-interacting Scalar Fields in the Broken Phase
1998-01-01
The classical kinetic theory of one-component self-interacting scalar fields is formulated in the broken symmetry phase and applied to the phenomenon of Landau damping. The domain of validity of the classical approach is found by comparing with the result of a 1-loop quantum calculation.
Broken Windows and Collective Efficacy
Directory of Open Access Journals (Sweden)
Aldrin Abdullah
2015-01-01
Full Text Available The broken windows thesis posits that signs of disorder increase crime and fear, both directly and indirectly. Although considerable theoretical evidence exists to support the idea that disorder is positively related to fear of crime, the empirical literature on examining the indirect effect of the individual’s perception of incivilities on fear of crime is limited, especially in developing countries. This research was conducted to assess the indirect relationship between perceived disorder and fear of crime through collective efficacy. A total of 235 households from Penang, Malaysia, participated in this study. Results reveal that high perception of disorder is negatively associated with collective efficacy. High collective efficacy is associated with low fear of crime. Moreover, a significant and indirect effect of disorder on fear of crime exists through collective efficacy. The results provide empirical support for the broken windows theory in the Malaysian context and suggest that both environmental conditions and interactions of residents play a role in the perceived fear of crime.
Dimensional reduction and dynamical symmetry breaking
Energy Technology Data Exchange (ETDEWEB)
Forgacs, P.; Zoupanos, G.
1984-11-22
We present a model in which the electroweak gauge group is broken according to a dynamical scenario based on the chiral symmetry breaking of high colour representations. The dynamical scenario requires also the existence of elementary Higgs fields, which in the present scheme come from the dimensional reduction of a pure gauge theory.
Dimensional reduction and dynamical symmetry breaking
Energy Technology Data Exchange (ETDEWEB)
Forgacs, P.; Zoupanos, G. (European Organization for Nuclear Research, Geneva (Switzerland))
1984-11-22
We present a model in which the electroweak gauge group is broken according to a dynamical scenario based on the chiral symmetry breaking of high colour representations. The dynamical scenario also requires the existence of elementary Higgs fields, which in the present scheme come from the dimensional reduction of a pure gauge theory.
Pole Inflation - Shift Symmetry and Universal Corrections
Broy, Benedict J.; Galante, Mario; Roest, Diederik; Westphal, Alexander
2015-01-01
An appealing explanation for the Planck data is provided by inflationary models with a singular non-canonical kinetic term: a Laurent expansion of the kinetic function translates into a potential with a nearly shift-symmetric plateau in canonical fields. The shift symmetry can be broken at large
Self-consistent Models of Strong Interaction with Chiral Symmetry
Nambu, Y.; Pascual, P.
1963-04-01
Some simple models of (renormalizable) meson-nucleon interaction are examined in which the nucleon mass is entirely due to interaction and the chiral ( gamma {sub 5}) symmetry is "broken'' to become a hidden symmetry. It is found that such a scheme is possible provided that a vector meson is introduced as an elementary field. (auth)
Generalization of Friedberg-Lee symmetry
Huang, Chao-Shang; Li, Tianjun; Liao, Wei; Zhu, Shou-Hua
2008-07-01
We study the possible origin of Friedberg-Lee symmetry. First, we propose the generalized Friedberg-Lee symmetry in the potential by including the scalar fields in the field transformations, which can be broken down to the Friedberg-Lee symmetry spontaneously. We show that the generalized Friedberg-Lee symmetry allows a typical form of Yukawa couplings, and the realistic neutrino masses and mixings can be generated via the seesaw mechanism. If the right-handed neutrinos transform nontrivially under the generalized Friedberg-Lee symmetry, we can have the testable TeV scale seesaw mechanism. Second, we present two models with the SO(3)×U(1) global flavor symmetry in the lepton sector. After the flavor symmetry breaking, we can obtain the charged lepton masses, and explain the neutrino masses and mixings via the seesaw mechanism. Interestingly, the complete neutrino mass matrices are similar to those of the above models with generalized Friedberg-Lee symmetry. So the Friedberg-Lee symmetry is the residual symmetry in the neutrino mass matrix after the SO(3)×U(1) flavor symmetry breaking.
Hairs of discrete symmetries and gravity
Directory of Open Access Journals (Sweden)
Kang Sin Choi
2017-06-01
Full Text Available Gauge symmetries are known to be respected by gravity because gauge charges carry flux lines, but global charges do not carry flux lines and are not conserved by gravitational interaction. For discrete symmetries, they are spontaneously broken in the Universe, forming domain walls. Since the realization of discrete symmetries in the Universe must involve the vacuum expectation values of Higgs fields, a string-like configuration (hair at the intersection of domain walls in the Higgs vacua can be realized. Therefore, we argue that discrete charges are also respected by gravity.
Hairs of discrete symmetries and gravity
Choi, Kang Sin; Kim, Jihn E.; Kyae, Bumseok; Nam, Soonkeon
2017-06-01
Gauge symmetries are known to be respected by gravity because gauge charges carry flux lines, but global charges do not carry flux lines and are not conserved by gravitational interaction. For discrete symmetries, they are spontaneously broken in the Universe, forming domain walls. Since the realization of discrete symmetries in the Universe must involve the vacuum expectation values of Higgs fields, a string-like configuration (hair) at the intersection of domain walls in the Higgs vacua can be realized. Therefore, we argue that discrete charges are also respected by gravity.
Kac-Moody Symmetry in Hosotani Model
Shiraishi, Kiyoshi
2012-01-01
The symmetry of the massive tower of fields in higher-dimensional Yang-Mills theory compactified on a space-time of the form M_d x S^1 is clarified. The transformations form a loop algebra, a class of Kac-Moody algebras. Since the symmetry is spontaneously broken, vector fields "eat" Goldstone bosons and acquire masses. The field of zero-mass mode can also become massive provided that the field of the internal component develops a vacuum expectation value. The relation between the "restoration" of the symmetry in massive modes and the gauge transformation of the zero-mode vacuum field is discussed.
Mass spectra in softly broken ${\\cal N}=2$ SQCD
Chernyak, Victor L
2016-01-01
Considered is ${\\cal N}=2\\,\\, SU(N_c)$ or $U(N_c)$ SQCD with $N_c+1
Continuous Global Symmetries and Hyperweak Interactions in String Compactifications
Burgess, C P; Hung, L-Y; Kom, C H; Maharana, A; Quevedo, Fernando
2008-01-01
We revisit general arguments for the absence of exact continuous global symmetries in string compactifications and extend them to D-brane models. We elucidate the various ways approximate continuous global symmetries arise in the 4-dimensional effective action. In addition to two familiar methods - axionic Peccei-Quinn symmetries and remnant global abelian symmetries from Green-Schwarz gauge symmetry breaking - we identify new ways to generate approximate continuous global symmetries. Two methods stand out, both of which occur for local brane constructions within the LARGE volume scenario of moduli stabilisation. The first is the generic existence of continuous non-abelian global symmetries associated with local Calabi-Yau isometries. These symmetries are exact in the non-compact limit and are spontaneously broken by the LARGE volume, with breaking effects having phenomenologically interesting sizes \\sim 0.01 for plausible choices for underlying parameters. Such approximate flavour symmetries are phenomenolog...
New technique for withdrawing broken sheath
Directory of Open Access Journals (Sweden)
Süleyman Cagan Efe
2016-03-01
Full Text Available A sheath that is broken inside vessel is a rare complication, and intravascular fragments from broken sheaths are retrieving transcutaneously by techniques including the loop snare catheter, basket catheter, and grasping/biopsy forceps. We reported a less common type of broken central venous sheath in location and a successful unique technique for retrieving it from subclavian vein by using noncompliant balloon from 40 year old female patient.
Grand Symmetry, Spectral Action, and the Higgs mass
Devastato, Agostino; Martinetti, Pierre
2013-01-01
In the context of the spectral action and noncommutative geometry approach to the standard model, we build a model based on a larger symmetry. This symmetry satisfies all the conditions to have a noncommutative manifold, and mixes gauge and spin degrees of freedom and does not introduce extra fermions. With this "grand symmetry" it is natural to have the scalar field necessary to obtain the Higgs mass in the vicinity of 126 GeV. The spectral action breaks the grand symmetry to the standard model algebra. This breaking also gives the spin structure of spacetime as broken symmetry.
Häring, Reto Andreas
1993-01-01
The representations of the observable algebra of a low dimensional quantum field theory form the objects of a braided tensor category. The search for gauge symmetry in the theory amounts to finding an algebra which has the same representation category. In this paper we try to establish that every quantum field theory satisfying some basic axioms posseses a weak quasi Hopf algebra as gauge symmetry. The first step is to construct a functor from the representation category to the category of finite dimensional vector spaces. Given such a functor we can use a generalized reconstruction theorem to find the symmetry algebra. It is shown how this symmetry algebra is used to build a gauge covariant field algebra and we investigate the question why this generality is necessary.
Institute of Scientific and Technical Information of China (English)
WANG Dian-Fu
2008-01-01
In terms of the Nambu-Jona-Lasinio mechanism, dynamical breaking of gauge symmetry for the maximally generalized Yang-Mills model is investigated. The gauge symmetry behavior at finite temperature is also investigated and it is shown that the gauge symmetry broken dynamically at zero temperature can be restored at finite temperatures.
Shape Transitions and Chiral Symmetry Breaking in the Energy Landscape of the Mitotic Chromosome
Zhang, Bin
2015-01-01
We derive an unbiased information theoretic energy landscape for chromosomes at metaphase using a maximum entropy approach that accurately reproduces the details of the experimentally measured pair-wise contact probabilities between genomic loci. Dynamical simulations using this landscape lead to cylindrical, helically twisted structures reflecting liquid crystalline order. These structures are similar to those arising from a generic ideal homogenized chromosome energy landscape. The helical twist can be either right or left handed so chiral symmetry is broken spontaneously. The ideal chromosome landscape when augmented by interactions like those leading to topologically associating domain (TAD) formation in the interphase chromosome reproduces these behaviors. The phase diagram of this landscape shows the helical fiber order and the cylindrical shape persist at temperatures above the onset of chiral symmetry breaking which is limited by the TAD interaction strength.
Shape Transitions and Chiral Symmetry Breaking in the Energy Landscape of the Mitotic Chromosome
Zhang, Bin; Wolynes, Peter G.
2016-06-01
We derive an unbiased information theoretic energy landscape for chromosomes at metaphase using a maximum entropy approach that accurately reproduces the details of the experimentally measured pairwise contact probabilities between genomic loci. Dynamical simulations using this landscape lead to cylindrical, helically twisted structures reflecting liquid crystalline order. These structures are similar to those arising from a generic ideal homogenized chromosome energy landscape. The helical twist can be either right or left handed so chiral symmetry is broken spontaneously. The ideal chromosome landscape when augmented by interactions like those leading to topologically associating domain formation in the interphase chromosome reproduces these behaviors. The phase diagram of this landscape shows that the helical fiber order and the cylindrical shape persist at temperatures above the onset of chiral symmetry breaking, which is limited by the topologically associating domain interaction strength.
Generalization of Friedberg-Lee Symmetry
Huang, Chao-Shang; Liao, Wei; Zhu, Shou-Hua
2008-01-01
We study the possible origin of Friedberg-Lee symmetry. First, we propose the generalized Friedberg-Lee symmetry in the potential by including the scalar fields in the field transformations, which can be broken down to the FL symmetry spontaneously. We show that the generalized Friedberg-Lee symmetry allows a typical form of Yukawa couplings, and the realistic neutrino masses and mixings can be generated via see-saw mechanism. If the right-handed neutrinos transform non-trivially under the generalized Friedberg-Lee symmetry, we can have the testable TeV scale see-saw mechanism. Second, we present two models with the $SO(3)\\times U(1)$ global flavour symmetry in the lepton sector. After the flavour symmetry breaking, we can obtain the charged lepton masses, and explain the neutrino masses and mixings via see-saw mechanism. Interestingly, the complete neutrino mass matrices are similar to those of the above models with generalized Friedberg-Lee symmetry. So the Friedberg-Lee symmetry is the residual symmetry in...
Harter, Andrew K.; Lee, Tony E.; Joglekar, Yogesh N.
2016-06-01
Aubry-André-Harper lattice models, characterized by a reflection-asymmetric sinusoidally varying nearest-neighbor tunneling profile, are well known for their topological properties. We consider the fate of such models in the presence of balanced gain and loss potentials ±i γ located at reflection-symmetric sites. We predict that these models have a finite PT -breaking threshold only for specific locations of the gain-loss potential and uncover a hidden symmetry that is instrumental to the finite threshold strength. We also show that the topological edge states remain robust in the PT -symmetry-broken phase. Our predictions substantially broaden the possible experimental realizations of a PT -symmetric system.
49 CFR 230.39 - Broken staybolts.
2010-10-01
..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Staybolts § 230.39 Broken staybolts. (a) Maximum allowable number of broken staybolts. No boiler shall be... inside the firebox or combustion chamber on a straight line. No boiler shall be allowed to remain...
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 ...
Cheng, Meng; Zaletel, Michael; Barkeshli, Maissam; Vishwanath, Ashvin; Bonderson, Parsa
2016-10-01
The Lieb-Schultz-Mattis theorem and its higher-dimensional generalizations by Oshikawa and Hastings require that translationally invariant 2D spin systems with a half-integer spin per unit cell must either have a continuum of low energy excitations, spontaneously break some symmetries, or exhibit topological order with anyonic excitations. We establish a connection between these constraints and a remarkably similar set of constraints at the surface of a 3D interacting topological insulator. This, combined with recent work on symmetry-enriched topological phases with on-site unitary symmetries, enables us to develop a framework for understanding the structure of symmetry-enriched topological phases with both translational and on-site unitary symmetries, including the effective theory of symmetry defects. This framework places stringent constraints on the possible types of symmetry fractionalization that can occur in 2D systems whose unit cell contains fractional spin, fractional charge, or a projective representation of the symmetry group. As a concrete application, we determine when a topological phase must possess a "spinon" excitation, even in cases when spin rotational invariance is broken down to a discrete subgroup by the crystal structure. We also describe the phenomena of "anyonic spin-orbit coupling," which may arise from the interplay of translational and on-site symmetries. These include the possibility of on-site symmetry defect branch lines carrying topological charge per unit length and lattice dislocations inducing degeneracies protected by on-site symmetry.
Pseudospin symmetry as an accidental symmetry in the relativistic framework
Energy Technology Data Exchange (ETDEWEB)
Marcos, S.; Niembro, R. [Universidad de Cantabria, Departamento de Fisica Moderna, Santander (Spain); Lopez-Quelle, M. [Universidad de Cantabria, Departamento de Fisica Aplicada, Santander (Spain); Savushkin, L.N. [St. Petersburg University for Telecommunications, Department of Physics, St. Petersburg (Russian Federation)
2008-08-15
We analyse the arguments used in the relativistic context to base the quasi-degeneracy of pseudospin doublets (PSDs) observed in atomic nuclei on the smallness of the single-particle central potential ({sigma}{sub S}+{sigma}{sub 0}), discussing, especially, the implications of the results obtained in the limit {sigma}{sub S}+{sigma}{sub 0}=0. We study also the transition from a relativistic model, where {sigma}{sub S}+{sigma}{sub 0} is a harmonic-oscillator potential and exhibits degenerate PSDs, to a more realistic one with broken pseudospin symmetry. We examine, in particular, the effect of the corresponding pseudospin symmetry-breaking term on the Dirac spinors of the PSDs. An extension of the Nilsson model to the relativistic case is also considered. (orig.)
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…
Superconformal Symmetry, NMSSM, and Inflation
Ferrara, Sergio; Linde, Andrei; Marrani, Alessio; Van Proeyen, Antoine
2011-01-01
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 (CSS) 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 coup...
Symmetry breaking around a wormhole
Choudhury, A. L.
1996-11-01
We have modified the extended version Coule and Maeda's version (D. H. Coule and Kei-ichi Maeda, Class.Quant.Grav.7,995(1990)) of the Gidding-Strominger model (S. B. Giddings and A. Strominger, Nucl.Phys. B307, 854(l988)) of the euclidean gravitational field interacting with axion. The new model has R-symmetry in contrast to the previous model. At the lowest perturbation case the model retains a wormhole solution. We assume that the scalar expands adiabatically and satisfies ideal gas law in a crude first approximation. Under the Higg's mechanism the symmetry can be broken at the tree approximation. This mechanism, we hope, can be used to introduce the degeneracy of quark masses.
Symmetry Nonrestoration in a Gross-Neveu Model with Random Chemical Potential
Hong, S I; Hong, Seok-In; Kogut, John B.
2001-01-01
We study the symmetry behavior of the Gross-Neveu model in three and two dimensions with random chemical potential. This is equivalent to a four-fermion model with charge conjugation symmetry as well as Z_2 chiral symmetry. At high temperature the Z_2 chiral symmetry is always restored. In three dimensions the initially broken charge conjugation symmetry is not restored at high temperature, irrespective of the value of the disorder strength. In two dimensions and at zero temperature the charge conjugation symmetry undergoes a quantum phase transition from a symmetric state (for weak disorder) to a broken state (for strong disorder) as the disorder strength is varied. For any given value of disorder strength, the high-temperature behavior of the charge conjugation symmetry is the same as its zero-temperature behavior. Therefore, in two dimensions and for strong disorder strength the charge conjugation symmetry is not restored at high temperature.
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.
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.
Duality as a gauge symmetry and topology change
Giveon, Amit
1993-01-01
Duality groups as (spontaneously broken) gauge symmetries for toroidal backgrounds, and their role in ($\\infty$-dimensional) underlying string gauge algebras are reviewed. For curved backgrounds, it is shown that there is a duality in the moduli space of WZNW sigma-models, that can be interpreted as a broken gauge symmetry. In particular, this duality relates the backgrounds corresponding to axially gauged abelian cosets $G/U(1)_a$, to vectorially gauged abelian cosets, $G/U(1)_v$. Finally, topology change in the moduli space of WZNW sigma-models is discussed.
Symmetry and the thermodynamics of currents in open quantum systems
Manzano, Daniel; Hurtado, Pablo I.
2014-09-01
Symmetry is a powerful concept in physics, and its recent application to understand nonequilibrium behavior is providing deep insights and groundbreaking exact results. Here we show how to harness symmetry to control transport and statistics in open quantum systems. Such control is enabled by a first-order-type dynamic phase transition in current statistics and the associated coexistence of different transport channels (or nonequilibrium steady states) classified by symmetry. Microreversibility then ensues, via the Gallavotti-Cohen fluctuation theorem, a twin dynamic phase transition for rare current fluctuations. Interestingly, the symmetry present in the initial state is spontaneously broken at the fluctuating level, where the quantum system selects the symmetry sector that maximally facilitates a given fluctuation. We illustrate these results in a qubit network model motivated by the problem of coherent energy harvesting in photosynthetic complexes, and introduce the concept of a symmetry-controlled quantum thermal switch, suggesting symmetry-based design strategies for quantum devices with controllable transport properties.
Directory of Open Access Journals (Sweden)
Kirstin Peters
2010-11-01
Full Text Available A well-known result by Palamidessi tells us that πmix (the π-calculus with mixed choice is more expressive than πsep (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 offered 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 (initial 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 reasonable encoding from πmix into πsep. We indicate how the respective proofs can be adapted and exhibit the consequences of varying notions of uniformity and reasonableness. In each case, the ability to break initial symmetries turns out to be essential.
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...
Spontaneous Chiral Symmetry Breaking as Condensation of Dynamical Chirality
Alexandru, Andrei
2012-01-01
The occurrence of spontaneous chiral symmetry breaking (SChSB) is equivalent to sufficient abundance of Dirac near-zeromodes. However, dynamical mechanism leading to breakdown of chiral symmetry should be naturally reflected in chiral properties of the modes. Here we offer such connection, presenting evidence that SChSB in QCD proceeds via the appearance of modes exhibiting dynamical tendency for local chiral polarization. These modes form a band of finite width Lambda_ch (chiral polarization scale) around the surface of otherwise anti--polarized Dirac sea, and condense. Lambda_ch characterizes the dynamics of the breaking phenomenon and can be converted to a quark mass scale, thus offering conceptual means to determine which quarks of nature are governed by broken chiral dynamics. It is proposed that, within the context of SU(3) gauge theories with fundamental Dirac quarks, mode condensation is equivalent to chiral polarization, making Lambda_ch an "order parameter" of SChSB. Several uses of these features, ...
Imaging chiral symmetry breaking from Kekulé bond order in graphene
Gutiérrez, Christopher; Kim, Cheol-Joo; Brown, Lola; Schiros, Theanne; Nordlund, Dennis; Lochocki, Edward B.; Shen, Kyle M.; Park, Jiwoong; Pasupathy, Abhay N.
2016-10-01
Chirality--or `handedness’--is a symmetry property crucial to fields as diverse as biology, chemistry and high-energy physics. In graphene, chiral symmetry emerges naturally as a consequence of the carbon honeycomb lattice. This symmetry can be broken by interactions that couple electrons with opposite momenta in graphene. Here we directly visualize the formation of Kekulé bond order, one such phase of broken chiral symmetry, in an ultraflat graphene sheet grown epitaxially on a copper substrate. We show that its origin lies in the interactions between individual vacancies in the copper substrate that are mediated electronically by the graphene. We show that this interaction causes the bonds in graphene to distort, creating a phase with broken chiral symmetry. The Kekulé ordering is robust at ambient temperature and atmospheric conditions, indicating that intercalated atoms may be harnessed to drive graphene and other two-dimensional materials towards electronically desirable and exotic collective phases.
Energy Technology Data Exchange (ETDEWEB)
Alshits, V.I.; Darinskii, A.N. [Russian Academy of Sciences, Moscow (Russian Federation); Radovich, A. [Kielce Technological Univ., Kielce (Poland)
1995-05-01
The specific features of acoustic wave reflection are analyzed at the interface between two hexagonal crystals with a sliding contact between them. Attention is focused on the angles of incidence corresponding to excitation of the leaky wave. The conditions supporting the existence of leaky waves are found. The expressions illustrating the behavior of plane wave transformation coefficients for reflection, refraction, and excitation of interfacial oscillations are found in analytic form. In addition, the features of nonmirror reflection are studied for a slightly diverging acoustic beam having initially a rectangular profile. The study deals with the case when the tangential projection of the {open_quotes}mean{close_quotes} wavevector for the beam is close to or coincides with the real part of the wavevector of the leaky wave. 9 refs., 10 figs.
Leadership, power and symmetry
DEFF Research Database (Denmark)
Spaten, Ole Michael
2016-01-01
regarding managers coaching their employees and it is asked; what contributes to coaching of high quality when one reflects on the power aspect as being immanent? Fourteen middle managers coached five of their employees, and all members of each party wrote down cues and experiences immediately after each......Research publications concerning managers who coach their own employees are barely visible despite its wide- spread use in enterprises (McCarthy & Milner, 2013; Gregory & Levy, 2011; Crabb, 2011). This article focuses on leadership, power and moments of symmetry in the coaching relationship...... session. Thereafter we executed qualitative interviews with both managers and employees. Subsequently, a Thematic Analysis resulted in several themes, including power and moments of symmetry in the coaching relationship. One main conclusion is that the most fruitful coaching was obtained when the coachee...
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.
Friedberg-Lee Symmetry for Quark Masses and Flavor Mixing
Ren, Ping
2008-01-01
We point out a generic correlation between the Friedberg-Lee symmetry of quark mass operators and the vanishing of quark masses. We make phenomenological explorations on two textures of quark mass matrices with the broken Friedberg-Lee symmetry. We present a new pattern of quark mass matrices in agreement with current experimental data. Both analytical and numerical results of our calculations are discussed in detail.
Inflationary Magnetogenesis with On-shell Local U(1) Symmetry
Domènech, Guillem; Lin, Chunshan; Sasaki, Misao
2017-08-01
We propose a new mechanism for inflationary magnetogenesis in which the local U(1) symmetry is broken during inflation. Nevertheless it is shown that the U(1) symmetry is recovered on-shell. We find that it is free from both the strong coupling and back reaction problems, and can explain the origin of cosmic magnetic fields on intergalactic scales, whose existence has been strongly suggested by recent observations.
Spontaneous symmetry breaking in the composite-vector-boson model
Energy Technology Data Exchange (ETDEWEB)
Garavaglia, T.
1986-11-15
Spontaneous symmetry breaking is discussed in the Abelian, QED-like, composite-vector-boson model. When the auxiliary vector field has a nonzero vacuum expectation value, a global symmetry, Lorentz invariance, is broken. It is shown that the regularization of the saddle-point conditions for the quantum fluctuation generating functional is consistent only with a spacelike vacuum expectation value for the auxiliary vector field.
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...
Peters, Kirstin; 10.4204/EPTCS.41.10
2010-01-01
A well-known result by Palamidessi tells us that \\pimix (the \\pi-calculus with mixed choice) is more expressive than \\pisep (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 offered 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 (initial) 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 reasonable encoding from \\pimix into \\pisep. We...
The Fading of Symmetry Non-Restoration at Finite Temperature
Gavela-Legazpi, Maria Belen; Rius, N; Vargas-Castrillon, S
1999-01-01
The fate of symmetries at high temperature determines the dynamics of the very early universe. It is conceivable that temperature effects favor symmetry breaking instead of restoration. Concerning global symmetries, the non-linear sigma model is analyzed in detail. For spontaneously broken gauge symmetries, we propose the gauge boson magnetic mass as a ``flag'' for symmetry (non)-restoration. We consider several cases: the standard model with one and two Higgs doublets in the perturbative regime, and the case of a strongly interacting Higgs sector. The latter is done in a model independent way with the tools provided by chiral Lagrangians. Our results clearly point towards restoration, a pattern consistent with recent lattice computations for global symmetries. In addition, we explicitly verify $BRST$ invariance for gauge theories at finite temperature.
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.
Anomalies in B-decays and U(2) flavor symmetry
Energy Technology Data Exchange (ETDEWEB)
Barbieri, Riccardo [Institute of Theoretical Studies, Zurich (Switzerland); Scuola Normale Superiore, INFN, Pisa (Italy); Isidori, Gino [Universitaet Zuerich, Physik-Institut, Zurich (Switzerland); Laboratori Nazionali di Frascati, INFN, Frascati (Italy); Pattori, Andrea [Universitaet Zuerich, Physik-Institut, Zurich (Switzerland); Universita di Padova, Dipartimento di Fisica e Astronomia ' G. Galilei' , Padua (Italy); Senia, Fabrizio [Scuola Normale Superiore, INFN, Pisa (Italy)
2016-02-15
The collection of a few anomalies in semileptonic B-decays invites to speculate about the emergence of some strikingly new phenomena. Here we offer a possible interpretation of these anomalies in the context of a weakly broken U(2){sup 5} flavor symmetry and leptoquark mediators. (orig.)
Thawing model and symmetry breaking in a coupled quintessence model
Honardoost, M; Sepangi, H R
2015-01-01
We consider the thawing model in the framework of coupled quintessence scenario. The effective potential has $Z_2$ symmetry which is broken spontaneously when dark matter density becomes less than a critical value leading the quintessence equation of state parameter to deviate from -1. Conditions required for this procedure are obtained and analytical solution for the equation of state parameter is derived.
Broken windows, mediocre methods, and substandard statistics
Wicherts, J.M.; Bakker, M.
2014-01-01
Broken windows theory states that cues of inappropriate behavior like litter or graffiti amplify norm-violating behavior. In a series of quasi-experiments, Keizer, Lindenberg, and Steg altered cues of inappropriate behavior in public places and observed how many passersby subsequently violated
PERIODIC-SOLUTIONS IN SPONTANEOUSLY BROKEN THEORIES
BRIHAYE, Y; KUNZ, J
1992-01-01
A class of spontaneously broken field theories is proposed, and the occurrence of their periodic, classical solutions is investigated in detail. The emergence of multiple solutions is observed, their normal modes of oscillation are studied, and the bifurcations of the classical energy functional are
Broken windows, mediocre methods, and substandard statistics
Wicherts, J.M.; Bakker, M.
2014-01-01
Broken windows theory states that cues of inappropriate behavior like litter or graffiti amplify norm-violating behavior. In a series of quasi-experiments, Keizer, Lindenberg, and Steg altered cues of inappropriate behavior in public places and observed how many passersby subsequently violated norms
Left-right symmetry and neutrino stability
Akhmedov, E K; Ranfone, S; Valle, José W F; Joshipura, A S; Ranfone, S; Valle, J W F
1995-01-01
We consider a left-right symmetric model in which neutrinos acquire mass due to the spontaneous violation of both the gauged B-L and a global U(1) symmetry broken by the vacuum expectation value (VEV) of a gauge singlet scalar boson \\VEV{\\sigma}. For suitable choices of \\VEV{\\sigma} consistent with all laboratory and astrophysical observations neutrinos will be unstable against majoron emission. All neutrino masses in the keV to MeV range are possible, since the expected neutrino decay lifetimes can be short enough to dilute their relic density below the cosmologically required level. A wide variety of possible new phenomena, associated to the presence of left-right symmetry and/or the global symmetry at the TeV scale, could therefore be observable, without conflict with cosmology. The latter includes the possibility of invisibly decaying higgs bosons, which can be searched at LEP, NLC and LHC.
Left-right symmetry and neutrino stability
Energy Technology Data Exchange (ETDEWEB)
Akhmedov, E.K. [Valencia Univ. (Spain). Dept. de Fisica Teorica; Joshipura, A.S. [Valencia Univ. (Spain). Dept. de Fisica Teorica; Ranfone, S. [Valencia Univ. (Spain). Dept. de Fisica Teorica; Valle, J.W.F. [Valencia Univ. (Spain). Dept. de Fisica Teorica
1995-05-08
We consider a left-right symmetric model in which neutrinos acquire mass due to the spontaneous violation of both the gauged B-L and a global U(1) symmetry broken by the vacuum expectation value (VEV) of a gauge singlet scalar boson left angle {sigma} right angle . For suitable choices of left angle {sigma} right angle consistent with all laboratory and astrophysical observations neutrinos will be unstable against majoron emission. All neutrino masses in the keV to MeV range are possible, since the expected neutrino decay lifetimes can be short enough to dilute their relic density below the cosmologically required level. A wide variety of possible new phenomena, associated to the presence of left-right symmetry and/or the global symmetry at the TeV scale, could therefore be observable, without conflict with cosmology. The latter includes the possibility of invisibly decaying higgs bosons, which can be searched at LEP, NLC and LHC. ((orig.)).
Spin-rotation symmetry breaking in the superconducting state of CuxBi2Se3
Matano, K.; Kriener, M.; Segawa, K.; Ando, Y.; Zheng, Guo-Qing
2016-09-01
Spontaneous symmetry breaking is an important concept for understanding physics ranging from the elementary particles to states of matter. For example, the superconducting state breaks global gauge symmetry, and unconventional superconductors can break further symmetries. In particular, spin-rotational symmetry is expected to be broken in spin-triplet superconductors. However, experimental evidence for such symmetry breaking has not been conclusively obtained so far in any candidate compounds. Here, using 77Se nuclear magnetic resonance measurements, we show that spin-rotation symmetry is spontaneously broken in the hexagonal plane of the electron-doped topological insulator Cu0.3Bi2Se3 below the superconducting transition temperature Tc = 3.4 K. Our results not only establish spin-triplet superconductivity in this compound, but may also serve to lay a foundation for the research of topological superconductivity.
New Mechanism of Flavor Symmetry Breaking from Supersymmetric Strong Dynamics
Carone, C D; Moroi, T; Carone, Christopher D.; Hall, Lawrence J.; Moroi, Takeo
1997-01-01
We present a class of supersymmetric models in which flavor symmetries are broken dynamically, by a set of composite flavon fields. The strong dynamics that is responsible for confinement in the flavor sector also drives flavor symmetry breaking vacuum expectation values, as a consequence of a quantum-deformed moduli space. Yukawa couplings result as a power series in the ratio of the confinement to Planck scale, and the fermion mass hierarchy depends on the differing number of preons in different flavor symmetry-breaking operators. We present viable non-Abelian and Abelian flavor models that incorporate this mechanism.
Fermion mass generation and electroweak symmetry breaking from colour forces
Energy Technology Data Exchange (ETDEWEB)
Zoupanos, G. (European Organization for Nuclear Research, Geneva (Switzerland))
1983-09-29
The colour gauge group is extended to SU(3) x SU(3) and is subsequently broken to diagonal SU(3)sub(c). Under the diagonal SU(3)sub(c) the fundamental fermionic constituents of the larger strong group become ordinary quarks plus new quarks with exotic quantum numbers. Chiral symmetry breaking in the exotic quark sector may occur at much larger mass scales than ordinary chiral symmetry breaking, and could produce dynamical breaking of electroweak gauge symmetry and radiative masses for the light fermions.
Hamiltonian dynamics and Noether symmetries in Extended Gravity Cosmology
Capozziello, Salvatore; Odintsov, Sergei D
2012-01-01
We discuss the Hamiltonian dynamics for cosmologies coming from Extended Theories of Gravity. In particular, minisuperspace models are taken into account searching for Noether symmetries. The existence of conserved quantities gives selection rule to recover classical behaviors in cosmic evolution according to the so called Hartle criterion, that allows to select correlated regions in the configuration space of dynamical variables. We show that such a statement works for general classes of Extended Theories of Gravity and is conformally preserved. Furthermore, the presence of Noether symmetries allows a straightforward classification of singularities that represent the points where the symmetry is broken. Examples of nonminimally coupled and higher-order models are discussed.
Optical chirality in gyrotropic media: symmetry approach
Proskurin, Igor; Ovchinnikov, Alexander S.; Nosov, Pavel; Kishine, Jun-ichiro
2017-06-01
We discuss optical chirality in different types of gyrotropic media. Our analysis is based on the formalism of nongeometric symmetries of Maxwell’s equations in vacuum generalized to material media with given constituent relations. This approach enables us to directly derive conservation laws related to nongeometric symmetries. For isotropic chiral media, we demonstrate that like a free electromagnetic field, both duality and helicity generators belong to the basis set of nongeometric symmetries that guarantees the conservation of optical chirality. In gyrotropic crystals, which exhibit natural optical activity, the situation is quite different from the case of isotropic media. For light propagating along a certain crystallographic direction, there arises two distinct cases: (1) the duality is broken but the helicity is preserved, or (2) only the duality symmetry survives. We show that the existence of one of these symmetries (duality or helicity) is enough to define optical chirality. In addition, we present examples of low-symmetry media, where optical chirality cannot be defined.
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.
Symmetry and symmetry breaking in particle physics
Tsou, ST
1998-01-01
Symmetry, in particular gauge symmetry, is a fundamental principle in theoretical physics. It is intimately connected to the geometry of fibre bundles. A refinement to the gauge principle, known as ``spontaneous symmetry breaking'', leads to one of the most successful theories in modern particle physics. In this short talk, I shall try to give a taste of this beautiful and exciting concept.
Beyond bilateral symmetry: geometric morphometric methods for any type of symmetry
Directory of Open Access Journals (Sweden)
Klingenberg Christian
2011-09-01
Full Text Available 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 and animals. For instance, some organisms have two axes of reflection symmetry (biradial symmetry; e.g. many algae, corals and flowers or rotational symmetry (e.g. sea urchins and many flowers. So far, there is no general method for the shape analysis of these types of symmetry. Results We generalize the morphometric methods currently used for the shape analysis of bilaterally symmetric objects so that they can be used for analyzing any type of symmetry. Our framework uses a mathematical definition of symmetry based on the theory of symmetry groups. This approach can be used to divide shape variation into a component of symmetric variation among individuals and one or more components of asymmetry. We illustrate this approach with data from a colonial coral that has ambiguous symmetry and thus can be analyzed in multiple ways. Our results demonstrate that asymmetric variation predominates in this dataset and that its amount depends on the type of symmetry considered in the analysis. Conclusions The framework for analyzing symmetry and asymmetry is suitable for studying structures with any type of symmetry in two or three dimensions. Studies of complex symmetries are promising for many contexts in evolutionary biology, such as fluctuating asymmetry, because these structures can potentially provide more information than structures with bilateral symmetry.
Alternative Schemes of Predicting Lepton Mixing Parameters from Discrete Flavor and CP Symmetry
Lu, Jun-Nan
2016-01-01
We suggest two alternative schemes to predict lepton mixing angles as well as $CP$ violating phases from a discrete flavor symmetry group combined with $CP$ symmetry. In the first scenario, the flavor and $CP$ symmetry is broken to the residual groups of the structure $Z_2\\times CP$ in the neutrino and charged lepton sectors. The resulting lepton mixing matrix depends on two free parameters $\\theta_{\
Dynamical restoration of ZN symmetry in SU(N) + Higgs theories
Biswal, Minati; Digal, Sanatan; Saumia, P. S.
2016-09-01
We study the ZN symmetry in SU (N) + Higgs theories with the Higgs field in the fundamental representation. The distributions of the Polyakov loop show that the ZN symmetry is explicitly broken in the Higgs phase. On the other hand inside the Higgs symmetric phase the Polyakov loop distributions and other physical observables exhibit the ZN symmetry. This effective realization of the ZN symmetry in the theory changes the nature of the confinement-deconfinement transition. We argue that the ZN symmetry will lead to time independent topological defect solutions in the Higgs symmetric deconfined phase which will play important role at high temperatures.
Dynamical Restoration of Z_N Symmetry in SU(N)+Higgs Theories
Biswal, Minati; Saumia, P S
2015-01-01
We study the Z_N symmetry in SU(N)+Higgs theories with the Higgs field in the fundamental representation. The distributions of the Polyakov loop show that the Z_N symmetry is explicitly broken in the Higgs phase. On the other hand, inside the Higgs symmetric phase the Polyakov loop distributions and other physical observables exhibit the Z_N symmetry. This effective restoration of the Z_N symmetry changes the nature of the confinement-deconfinenement transition. We argue that the Z_N symmetry will lead to time independent topological defect solutions in the Higgs symmetric deconfined phase which will play important role at high temperatures.
Simple Technique for Removing Broken Pedicular Screws
Directory of Open Access Journals (Sweden)
A Agrawal
2014-03-01
Full Text Available The procedure for removing a broken pedicle screw should ideally be technically easy and minimally invasive, as any damage to the pedicle, during removal of the broken screw, may weaken the pedicle, thus compromising on the success of re-instrumentation. We describe the case of a 32-year old man who had undergone surgery for traumatic third lumbar vertebral body fracture three years prior to current admission and had developed the complication of pedicle screw breakage within the vertebral body. The patient underwent re-exploration and removal of the distal screws. Through a paravertebral incision and muscle separation, the screws and rods were exposed and the implants were removed.
Broken Ergodicity in Ideal, Homogeneous, Incompressible Turbulence
Morin, Lee; Shebalin, John; Fu, Terry; Nguyen, Phu; Shum, Victor
2010-01-01
We discuss the statistical mechanics of numerical models of ideal homogeneous, incompressible turbulence and their relevance for dissipative fluids and magnetofluids. These numerical models are based on Fourier series and the relevant statistical theory predicts that Fourier coefficients of fluid velocity and magnetic fields (if present) are zero-mean random variables. However, numerical simulations clearly show that certain coefficients have a non-zero mean value that can be very large compared to the associated standard deviation. We explain this phenomena in terms of broken ergodicity', which is defined to occur when dynamical behavior does not match ensemble predictions on very long time-scales. We review the theoretical basis of broken ergodicity, apply it to 2-D and 3-D fluid and magnetohydrodynamic simulations of homogeneous turbulence, and show new results from simulations using GPU (graphical processing unit) computers.
The game of order and symmetry in matter and in culture
Caglioti, G.
1995-01-01
Symmetry, symmetry breaking and broken symmetries play a central role in science and art, as well as in our daily life. Symmetry - a no-change as the outcome of a change - is synonym of invariance or indiscernibility. As a permanent reference of a structure it is associated with the meaning of the structures and it is fundamental in order to describe them. But symmetry implies the impossibility to discern, that is to measure and to perceive. In order to measure and to perceive, that is to create information and knowledge, symmetry has to be broken. The game of life - a life made of selfreproducing information - develops on the watershed of broken symmetries: an ambiguous and indented ridge of symmetries that break and recover themselves in a continuous series of choices. But even the masterpieces of art of all time run on the same ridge. The musical language, for instance, is a universal language - it can be enjoyed without being translated - just because the two contradictory attitudes of the human soul - the symmetric or dreaming attitude and the "informed" or conscious one - compose themselves in it. Similarly, the most successful trademarks exhibit a measured combination of symmetric and therefore reassuring elements, and elements that break symmetry and, in this way, evoke dynamically the rising of new perspectives. During the conference many examples will be proposed, as well as some suggestive similarities between visual arts, music and science.
Effects of symmetry breaking in finite quantum systems
Energy Technology Data Exchange (ETDEWEB)
Birman, J.L. [Department of Physics, City College, City University of New York, New York, NY 10031 (United States); Nazmitdinov, R.G. [Departament de Fisica, Universitat de les Illes Balears, Palma de Mallorca 07122 (Spain); Bogolubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Yukalov, V.I., E-mail: yukalov@theor.jinr.ru [Bogolubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation)
2013-05-15
The review considers the peculiarities of symmetry breaking and symmetry transformations and the related physical effects in finite quantum systems. Some types of symmetry in finite systems can be broken only asymptotically. However, with a sufficiently large number of particles, crossover transitions become sharp, so that symmetry breaking happens similarly to that in macroscopic systems. This concerns, in particular, global gauge symmetry breaking, related to Bose–Einstein condensation and superconductivity, or isotropy breaking, related to the generation of quantum vortices, and the stratification in multicomponent mixtures. A special type of symmetry transformation, characteristic only for finite systems, is the change of shape symmetry. These phenomena are illustrated by the examples of several typical mesoscopic systems, such as trapped atoms, quantum dots, atomic nuclei, and metallic grains. The specific features of the review are: (i) the emphasis on the peculiarities of the symmetry breaking in finite mesoscopic systems; (ii) the analysis of common properties of physically different finite quantum systems; (iii) the manifestations of symmetry breaking in the spectra of collective excitations in finite quantum systems. The analysis of these features allows for the better understanding of the intimate relation between the type of symmetry and other physical properties of quantum systems. This also makes it possible to predict new effects by employing the analogies between finite quantum systems of different physical nature.
Single photon induced symmetry breaking of H2 dissociation
Energy Technology Data Exchange (ETDEWEB)
Martin, F.; Fernandez, J.; Havermeier, T.; Foucar, L.; Weber, Th; Kreidi, K.; Schoffler, M.; Schmidt, L.; Jahnke, T.; Landers, A.L.; Jagutzki, O.; Czasch, A.; Benis, E.; Osipov, T.; Belkacem, A.; Prior,M.H.; Schmidt-Bocking, H.; Cocke, C.L.; Dorner, R.
2006-12-06
H{sub 2}, the smallest and most abundant molecule in the universe, has a perfectly symmetric ground state. What does it take to break this symmetry? Here we show that the inversion symmetry can be broken by absorption of a linearly polarized photon, which itself has inversion symmetry. In particular, the emission of a photoelectron with subsequent dissociation of the remaining H{sub 2}{sup +} fragment shows no symmetry with respect to the ionic H+ and neutral H atomic fragments. This result is the consequence of the entanglement between symmetric and antisymmetric H{sub 2}{sup +} states resulting from autoionization. The mechanisms behind this symmetry breaking are general for all molecules.
Matrix Representation of Symmetry Operators in Elementary Crystallography
Cody, R. D.
1972-01-01
Presents the derivation of rotation and reflection matrix representation of symmetry operators as used in the initial discussion of crystal symmetry in elementary mineralogy at Iowa State University. Includes references and an appended list of matrix representations of the important crystallographic symmetry operators, excluding the trigonal and…
Gauge symmetries emerging from extra dimensions
Chkareuli, J. L.; Kepuladze, Z.
2016-09-01
We argue that extra dimensions with a properly chosen compactification scheme could be a natural source for emergent gauge symmetries. Actually, some proposed vector field potential terms or polynomial vector field constraints introduced in five-dimensional Abelian and non-Abelian gauge theory are shown to smoothly lead to spontaneous violation of an underlying 5D spacetime symmetry and generate pseudo-Goldstone vector modes as conventional 4D gauge boson candidates. As a special signature, there appear, apart from conventional gauge couplings, some properly suppressed direct multiphoton (multiboson, in general) interactions in emergent QED and Yang-Mills theories whose observation could shed light on their high-dimensional nature. Moreover, in emergent Yang-Mills theories an internal symmetry G also occurs spontaneously broken to its diagonal subgroups once 5D Lorentz violation happens. This breaking originates from the extra vector field components playing a role of some adjoint scalar field multiplet in the 4D spacetime. So, one naturally has the Higgs effect without a specially introduced scalar field multiplet. Remarkably, when being applied to grand unified theories (GUTs) this results in a fact that the emergent GUTs generically appear broken down to the Standard Model just at the 5D Lorentz violation scale M .
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.
Lattice Regularization and Symmetries
Hasenfratz, Peter; Von Allmen, R; Allmen, Reto von; Hasenfratz, Peter; Niedermayer, Ferenc
2006-01-01
Finding the relation between the symmetry transformations in the continuum and on the lattice might be a nontrivial task as illustrated by the history of chiral symmetry. Lattice actions induced by a renormalization group procedure inherit all symmetries of the continuum theory. We give a general procedure which gives the corresponding symmetry transformations on the lattice.
Deriving diffeomorphism symmetry
Kleppe, Astri
2014-01-01
In an earlier article, we have "derived" space, as a part of the Random Dynamics project. In order to get locality we need to obtain reparametrization symmetry, or equivalently, diffeomorphism symmetry. There we sketched a procedure for how to get locality by first obtaining reparametrization symmetry, or equivalently, diffeomorphism symmetry. This is the object of the present article.
Desert wanderings: pathways for whole, broken and shattered psyches.
Joseph, S M
2000-07-01
This paper challenges an implicit assumption of analytical psychology that centred, mandalic images express psychical wholeness in an optimal fashion across cultures and eras. I suggest that liminal, bardo-like eras, such as our 'post-modern' one, constellate complex, antithetical and ec-centric images, which are process-oriented and which encompass wholeness and fragmentation, conjunction and disjunction, thus holding and expressing actual individual and collective experience. In our era, we inhabit unfolding states of wholeness, brokenness and fragmentation. Images of wholeness, emerging spontaneously from the unconscious, may reflect part or all of these contradictory realities. Examples of such antithetical Self-images are developed from the ancient midrashic traditions of the rabbis; from Jung's contemporary exposition of Pauli's 'world-clock' dream; from Kepler's discovery, at the dawn of modernity, that the planets circled the sun in ellipses rather than circles; and from a clinical illustration.
Directory of Open Access Journals (Sweden)
Hongfa Xu
2017-01-01
Full Text Available To estimate postgrouting rock mass strength growth is important for engineering design. In this paper, using self-developed indoor pressure-grouting devices, 19 groups of test cubic blocks were made of the different water cement ratio grouting into the broken rock of three kinds of particle sizes. The shear strength parameters of each group under different conditions were tested. Then this paper presents a quantitative calculation method for predicting the strength growth of grouted broken rock. Relational equations were developed to investigate the relationship between the growth rates of uniaxial compressive strength (UCS, absolute value of uniaxial tensile strength (AUTS, internal friction angle, and cohesion for post- to pregrouting broken rock based on Mohr-Coulomb strength criterion. From previous test data, the empirical equation between the growth rate of UCS and the ratio of the initial rock mass UCS to the grout concretion UCS has been determined. The equations of the growth rates of the internal friction coefficient and UCS for grouting broken rock with rock mass rating (RMR and its increment have been established. The calculated results are consistent with the experimental results. These observations are important for engineered design of grouting reinforcement for broken rock mass.
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
Heeck, Julian
2014-01-01
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 Stueckelberg mass $M_{Z'}$, and the kinetic mixing angle $\\chi$. The new force could manifest itself at any scale, and we collect and derive bounds on g' over the entire testable range $M_{Z'}$ = 0 - $10^{13}$ 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 < $M_{Z'}$ < 10 GeV due to resonant enhancement of the rate $\\overline{f} f \\leftrightarrow \\overline{\
Van Isacker, P
2010-01-01
The use of dynamical symmetries or spectrum generating algebras for the solution of the nuclear many-body problem is reviewed. General notions of symmetry and dynamical symmetry in quantum mechanics are introduced and illustrated with simple examples such as the SO(4) symmetry of the hydrogen atom and the isospin symmetry in nuclei. Two nuclear models, the shell model and the interacting boson model, are reviewed with particular emphasis on their use of group-theoretical techniques.
Fine-tuning problem in renormalized perturbation theory: Spontaneously-broken gauge models
Energy Technology Data Exchange (ETDEWEB)
Foda, O.E. (Purdue Univ., Lafayette, IN (USA). Dept. of Physics)
1983-04-28
We study the stability of tree-level gauge hierarchies at higher orders in renormalized perturbation theory, in a model with spontaneously-broken gauge symmetries. We confirm previous results indicating that if the model is renormalized using BPHZ, then the tree-level hierarchy is not upset by the radiative corrections. Consequently, no fine-tuning of the initial parameters is required to maintain it, in contrast to the result obtained using Dimensional Renormalization. This verifies the conclusion that the need for fine-tuning, when it arises, is an artifact of the application of a certain class of renormalization schemes.
Comments on Holography with Broken Lorentz Invariance
Gordeli, Ivan
2009-01-01
Recently a family of solutions of the Einstein equations in backgrounds with broken Lorentz invariance was found ArXiv:0712.1136. We show that the gravitational solution recently obtained by Kachru, Liu and Mulligan in ArXiv:0808.1725 is a part of the former solution which was derived earlier in the framework of extra dimensional theories. We show how the energy-momentum and Einstein tensors are related and establish a correspondence between parameters which govern Lorentz invariance violation. At the end we speculate on relations between the RG flow of a boundary theory and asymptotic behavior of gravitational solutions in the bulk.
Broken safety pin in bronchus - Anaesthetic considerations
Directory of Open Access Journals (Sweden)
Roona Shad
2012-01-01
Full Text Available Safety pins are not commonly aspirated objects in infants and form only a small fraction of all the metallic foreign body (FB which accounts for 4.4% of all foreign bodies found in tracheobronchial tree. Bronchoscopy procedure has various complications, in addition to failure to remove FB due to its impaction, especially with metallic pointed objects ending up in open surgical removal. Infant with inhaled foreign body are always a challenge to anaesthetist. We had one such case of broken safety pin impacted in the wall of right bronchus of an infant with failure to remove on repeated attempts at rigid bronchoscopy.
Broken safety pin in bronchus - Anaesthetic considerations.
Shad, Roona; Agarwal, Aditya
2012-11-01
Safety pins are not commonly aspirated objects in infants and form only a small fraction of all the metallic foreign body (FB) which accounts for 4.4% of all foreign bodies found in tracheobronchial tree. Bronchoscopy procedure has various complications, in addition to failure to remove FB due to its impaction, especially with metallic pointed objects ending up in open surgical removal. Infant with inhaled foreign body are always a challenge to anaesthetist. We had one such case of broken safety pin impacted in the wall of right bronchus of an infant with failure to remove on repeated attempts at rigid bronchoscopy.
Broken Lifshitz invariance, spin waves and hydrodynamics
Roychowdhury, Dibakar
2016-01-01
In this paper, based on the basic principles of thermodynamics, we explore the hydrodynamic regime of interacting Lifshitz field theories in the presence of broken rotational invariance. We compute the entropy current and discover new dissipative effects those are consistent with the principle of local entropy production in the fluid. In our analysis, we consider both the parity even as well as the parity odd sector upto first order in the derivative expansion. Finally, we argue that the present construction of the paper could be systematically identified as that of the hydrodynamic description associated with \\textit{spin waves} (away from the domain of quantum criticality) under certain limiting conditions.
1999-01-01
The effective theory of low frequency fluctuations of selfinteracting scalar fields is constructed in the broken symmetry phase. The theory resulting from integrating fluctuations with frequencies much above the spontanously generated mass scale $(p_0>>M)$ is found to be local. Non-local dynamics, especially Landau damping emerges under the effect of fluctuations in the $p_0 \\sim M$ region. A kinetic theory of relativistic scalar gas particles interacting via their locally variable mass with ...
Is space-time symmetry a suitable generalization of parity-time symmetry?
Energy Technology Data Exchange (ETDEWEB)
Amore, Paolo, E-mail: paolo.amore@gmail.com [Facultad de Ciencias, CUICBAS, Universidad de Colima, Bernal Díaz del Castillo 340, Colima, Colima (Mexico); Fernández, Francisco M., E-mail: fernande@quimica.unlp.edu.ar [INIFTA (UNLP, CCT La Plata-CONICET), División Química Teórica, Diag. 113 y 64 (S/N), Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina); Garcia, Javier [INIFTA (UNLP, CCT La Plata-CONICET), División Química Teórica, Diag. 113 y 64 (S/N), Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina)
2014-11-15
We discuss space-time symmetric Hamiltonian operators of the form H=H{sub 0}+igH{sup ′}, where H{sub 0} is Hermitian and g real. H{sub 0} is invariant under the unitary operations of a point group G while H{sup ′} is invariant under transformation by elements of a subgroup G{sup ′} of G. If G exhibits irreducible representations of dimension greater than unity, then it is possible that H has complex eigenvalues for sufficiently small nonzero values of g. In the particular case that H is parity-time symmetric then it appears to exhibit real eigenvalues for all 0
Ermolenko, Alexander E; Perepada, Elena A
2007-01-01
The paper contains a description of basic regularities in the manifestation of symmetry of human structural organization and its ontogenetic and phylogenetic development. A concept of macrobiocrystalloid with inherent complex symmetry is proposed for the description of the human organism in its integrity. The symmetry can be characterized as two-plane radial (quadrilateral), where the planar symmetry is predominant while the layout of organs of radial symmetry is subordinated to it. Out of the two planes of symmetry (sagittal and horizontal), the sagittal plane is predominant. The symmetry of the chromosome, of the embrio at the early stages of cell cleavage as well as of some organs and systems in their phylogenetic development is described. An hypothesis is postulated that the two-plane symmetry is formed by two mechanisms: a) the impact of morphogenetic fields of the whole crystalloid organism during embriogenesis and, b) genetic mechanisms of the development of chromosomes having two-plane symmetry.
Absorption of solar radiation in broken clouds
Energy Technology Data Exchange (ETDEWEB)
Zuev, V.E.; Titov, G.A.; Zhuravleva, T.B. [Institute of Atmospheric Optics, Tomsk (Russian Federation)
1996-04-01
It is recognized now that the plane-parallel model unsatisfactorily describes the transfer of radiation through broken clouds and that, consequently, the radiation codes of general circulation models (GCMs) must be refined. However, before any refinement in a GCM code is made, it is necessary to investigate the dependence of radiative characteristics on the effects caused by the random geometry of cloud fields. Such studies for mean fluxes of downwelling and upwelling solar radiation in the visible and near-infrared (IR) spectral range were performed by Zuev et al. In this work, we investigate the mean spectral and integrated absorption of solar radiation by broken clouds (in what follows, the term {open_quotes}mean{close_quotes} will be implied but not used, for convenience). To evaluate the potential effect of stochastic geometry, we will compare the absorption by cumulus (0.5 {le} {gamma} {le} 2) to that by equivalent stratus ({gamma} <<1) clouds; here {gamma} = H/D, H is the cloud layer thickness and D the characteristic horizontal cloud size. The equivalent stratus clouds differ from cumulus only in the aspect ratio {gamma}, all the other parameters coinciding.
Thick brane solitons breaking $Z_2$ symmetry
Peyravi, Marzieh; Lobo, Francisco S N
2015-01-01
New soliton solutions for thick branes in 4 + 1 dimensions are considered in this article. In particular, brane models based on the sine-Gordon (SG), $\\varphi^{4}$ and $\\varphi^{6}$ scalar fields are investigated; in some cases $Z_{2}$ symmetry is broken. Besides, these soliton solutions are responsible for supporting and stabilizing the thick branes. In these models, the origin of the symmetry breaking resides in the fact that the modified scalar field potential may have non-degenerate vacuua and these non-degenerate vacuua determine the cosmological constant on both sides of the brane. At last, in order to explore the particle motion in the neighborhood of the brane, the geodesic equations along the fifth dimension are studied.
Symmetry breaking in non conservative systems
Martínez-Pérez, N E
2016-01-01
We apply Noether's theorem to show how the invariances of conservative systems are broken for nonconservative systems, in the variational formulation of Galley. This formulation considers a conservative action, extended by the inclusion of a time reversed sector and a nonconservative generalized potential. We assume that this potential is invariant under the symmetries of the initial conservative system. The breaking occurs because the time reversed sector requires inverse symmetry transformations, under which the nonconservative potential is not invariant. The resulting violation of the conservation laws is consistent with the equations of motion. We generalize this formulation for fermionic and sypersymmetric systems. In the case of a supersymmetric oscillator, the effect of damping is that the bosonic and fermionic components become different frequencies. Considering that initially the nonconservative action is invariant under supersymmetry, and that the breaking is associated to an instability, this resul...
Rotational symmetry breaking in baby Skyrme models
Hen, Itay
2007-01-01
We consider multisolitons with charges 1 =< B =< 5 in the baby Skyrme model for the one-parametric family of potentials U=\\mu^2 (1-\\phi_3)^s with 0symmetry is exhibited only in the small s region; above a certain critical value of s, this symmetry is broken and a strong repulsion between the constituent one-Skyrmions becomes apparent. We also compute the spatial energy distributions of these solutions.
Dengiz, Suat
2014-01-01
Weyl-invariant extensions of three-dimensional New Massive Gravity, generic n-dimensional Quadratic Curvature Gravity theories and three-dimensional Born-Infeld gravity theory are analyzed in details. As required by Weyl-invariance, the actions of these gauge theories do not contain any dimensionful parameter hence the local symmetry is spontaneously broken in (Anti) de Sitter vacua in complete analogy with the Standard Model Higgs mechanism. In flat vacuum, symmetry breaking mechanism is more complicated: The dimensionful parameters come from dimensional transmutation in the quantum field theory; therefore, the conformal symmetry is radiatively broken (at two loop level in 3-dimensions and at one-loop level in 4-dimensions) \\`{a} la Coleman-Weinberg mechanism. In the broken phases, save for New Massive Gravity, the theories generically propagate with a unitary (tachyon and ghost-free) massless tensor, massive (or massless) vector and massless scalar particles for the particular intervals of the dimensionless...
Spin and Orbital Angular Momenta of Light Reflected from a Cone
Mansuripur, Masud; Wright, Ewan M; 10.1103/PhysRevA.84.033813
2012-01-01
We examine several retro-reflecting optical elements, each involving two reflections. In the case of a hollow metallic cone having an apex angle of 90\\degree, a circularly-polarized incident beam acquires, upon reflection, the opposite spin angular momentum. However, no angular momentum is transferred to the cone, because the reflected beam picks up an orbital angular momentum that is twice as large but opposite in direction to that of its spin. A 90\\degree cone made of a transparent material in which the incident light suffers two total internal reflections before returning, may be designed to endow the retro-reflected beam with different mixtures of orbital and spin angular momenta. Under no circumstances, however, is it possible to transfer angular momentum from the light beam to the cone without either allowing absorption or breaking the axial symmetry of the cone. A simple example of broken symmetry is provided by a wedge-shaped metallic reflector having an apex angle of 90\\degree, which picks up angular...
Brading, Katherine; Castellani, Elena
2010-01-01
Preface; Copyright acknowledgements; List of contributors; 1. Introduction; Part I. Continuous Symmetries: 2. Classic texts: extracts from Weyl and Wigner; 3. Review paper: On the significance of continuous symmetry to the foundations of physics C. Martin; 4. The philosophical roots of the gauge principle: Weyl and transcendental phenomenological idealism T. Ryckman; 5. Symmetries and Noether's theorems K. A. Brading and H. R. Brown; 6. General covariance, gauge theories, and the Kretschmann objection J. Norton; 7. The interpretation of gauge symmetry M. Redhead; 8. Tracking down gauge: an ode to the constrained Hamiltonian formalism J. Earman; 9. Time-dependent symmetries: the link between gauge symmetries and indeterminism D. Wallace; 10. A fourth way to the Aharanov-Bohm effect A. Nounou; Part II. Discrete Symmetries: 11. Classic texts: extracts from Lebniz, Kant and Black; 12. Review paper: Understanding permutation symmetry S. French and D. Rickles; 13. Quarticles and the identity of discernibles N. Hugget; 14. Review paper: Handedness, parity violation, and the reality of space O. Pooley; 15. Mirror symmetry: what is it for a relational space to be orientable? N. Huggett; 16. Physics and Leibniz's principles S. Saunders; Part III. Symmetry Breaking: 17: Classic texts: extracts from Curie and Weyl; 18. Extract from G. Jona-Lasinio: Cross-fertilization in theoretical physics: the case of condensed matter and particle physics G. Jona-Lasinio; 19. Review paper: On the meaning of symmetry breaking E. Castellani; 20. Rough guide to spontaneous symmetry breaking J. Earman; 21. Spontaneous symmetry breaking: theoretical arguments and philosophical problems M. Morrison; Part IV. General Interpretative Issues: 22. Classic texts: extracts from Wigner; 23. Symmetry as a guide to superfluous theoretical structure J. Ismael and B. van Fraassen; 24. Notes on symmetries G. Belot; 25. Symmetry, objectivity, and design P. Kosso; 26. Symmetry and equivalence E. Castellani.
Rašin, Andrija
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.
Directory of Open Access Journals (Sweden)
Joe Rosen
2005-12-01
Full Text Available Abstract: The symmetry principle is described in this paper. The full details are given in the book: J. Rosen, Symmetry in Science: An Introduction to the General Theory (Springer-Verlag, New York, 1995.
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.
Neutrinos and flavor symmetries
Tanimoto, Morimitsu
2015-07-01
We discuss the recent progress of flavor models with the non-Abelian discrete symmetry in the lepton sector focusing on the θ13 and CP violating phase. In both direct approach and indirect approach of the flavor symmetry, the non-vanishing θ13 is predictable. The flavor symmetry with the generalised CP symmetry can also predicts the CP violating phase. We show the phenomenological analyses of neutrino mixing for the typical flavor models.
Neutrinos and flavor symmetries
Energy Technology Data Exchange (ETDEWEB)
Tanimoto, Morimitsu
2015-07-15
We discuss the recent progress of flavor models with the non-Abelian discrete symmetry in the lepton sector focusing on the θ{sub 13} and CP violating phase. In both direct approach and indirect approach of the flavor symmetry, the non-vanishing θ{sub 13} is predictable. The flavor symmetry with the generalised CP symmetry can also predicts the CP violating phase. We show the phenomenological analyses of neutrino mixing for the typical flavor models.
The breaking of quantum double symmetries by defect condensation
Bais, F. A.; Mathy, C. J. M.
2007-03-01
In this paper, we study the phenomenon of Hopf or more specifically quantum double symmetry breaking. We devise a criterion for this type of symmetry breaking which is more general than the one originally proposed in F.A. Bais, B.J. Schroers, J.K. Slingerland [Broken quantum symmetry and confinement phases in planar physics, Phys. Rev. Lett. 89 (2002) 181601]; Hopf symmetry breaking and confinement in (2+1)-dimensional gauge theory, JHEP 05 (2003) 068], and therefore extends the number of possible breaking patterns that can be described consistently. We start by recalling why the extended symmetry notion of quantum double algebras is an optimal tool when analyzing a wide variety of two-dimensional physical systems including quantum fluids, crystals and liquid crystals. The power of this approach stems from the fact that one may characterize both ordinary and topological modes as representations of a single (generally nonabelian) Hopf symmetry. In principle a full classification of defect mediated as well as ordinary symmetry breaking patterns and subsequent confinement phenomena can be given. The formalism applies equally well to systems exhibiting global, local, internal and/or external (i.e. spatial) symmetries. The subtle differences in interpretation for the various situations are pointed out. We show that the Hopf symmetry breaking formalism reproduces the known results for ordinary (electric) condensates, and we derive formulae for defect (magnetic) condensates which also involve the phenomenon of symmetry restoration. These results are applied in two papers which will be published in parallel [C.J.M. Mathy, F.A. Bais, Nematic phases and the breaking of double symmetries, arXiv:cond-mat/0602109, 2006; F.A. Bais, C.J.M. Mathy, Defect mediated melting and the breaking of quantum double symmetries, arXiv:cond-mat/0602101, 2006].
Exposing local symmetries in distorted driven lattices via time-averaged invariants
Wulf, T.; Morfonios, C. V.; Diakonos, F. K.; Schmelcher, P.
2016-05-01
Time-averaged two-point currents are derived and shown to be spatially invariant within domains of local translation or inversion symmetry for arbitrary time-periodic quantum systems in one dimension. These currents are shown to provide a valuable tool for detecting deformations of a spatial symmetry in static and driven lattices. In the static case the invariance of the two-point currents is related to the presence of time-reversal invariance and/or probability current conservation. The obtained insights into the wave functions are further exploited for a symmetry-based convergence check which is applicable for globally broken but locally retained potential symmetries.
Exposing local symmetries in distorted driven lattices via time-averaged invariants.
Wulf, T; Morfonios, C V; Diakonos, F K; Schmelcher, P
2016-05-01
Time-averaged two-point currents are derived and shown to be spatially invariant within domains of local translation or inversion symmetry for arbitrary time-periodic quantum systems in one dimension. These currents are shown to provide a valuable tool for detecting deformations of a spatial symmetry in static and driven lattices. In the static case the invariance of the two-point currents is related to the presence of time-reversal invariance and/or probability current conservation. The obtained insights into the wave functions are further exploited for a symmetry-based convergence check which is applicable for globally broken but locally retained potential symmetries.
A symmetry-respecting topologically-ordered surface phase of 3d electron topological insulators
Metlitski, Max A.; Kane, C. L.; Fisher, Matthew P. A.
2013-01-01
A 3d electron topological insulator (ETI) is a phase of matter protected by particle-number conservation and time-reversal symmetry. It was previously believed that the surface of an ETI must be gapless unless one of these symmetries is broken. A well-known symmetry-preserving, gapless surface termination of an ETI supports an odd number of Dirac cones. In this paper we deduce a symmetry-respecting, gapped surface termination of an ETI, which carries an intrinsic 2d topological order, Moore-R...
Leptonic Dirac CP violation predictions from residual discrete symmetries
Girardi, I.; Petcov, S. T.; Stuart, Alexander J.; Titov, A. V.
2016-01-01
Assuming that the observed pattern of 3-neutrino mixing is related to the existence of a (lepton) flavour symmetry, corresponding to a non-Abelian discrete symmetry group Gf, and that Gf is broken to specific residual symmetries Ge and Gν of the charged lepton and neutrino mass terms, we derive sum rules for the cosine of the Dirac phase δ of the neutrino mixing matrix U. The residual symmetries considered are: i) Ge =Z2 and Gν =Zn, n > 2 or Zn ×Zm, n , m ≥ 2; ii) Ge =Zn, n > 2 or Zn ×Zm, n , m ≥ 2 and Gν =Z2; iii) Ge =Z2 and Gν =Z2; iv) Ge is fully broken and Gν =Zn, n > 2 or Zn ×Zm, n , m ≥ 2; and v) Ge =Zn, n > 2 or Zn ×Zm, n , m ≥ 2 and Gν is fully broken. For given Ge and Gν, the sum rules for cos δ thus derived are exact, within the approach employed, and are valid, in particular, for any Gf containing Ge and Gν as subgroups. We identify the cases when the value of cos δ cannot be determined, or cannot be uniquely determined, without making additional assumptions on unconstrained parameters. In a large class of cases considered the value of cos δ can be unambiguously predicted once the flavour symmetry Gf is fixed. We present predictions for cos δ in these cases for the flavour symmetry groups Gf =S4, A4, T‧ and A5, requiring that the measured values of the 3-neutrino mixing parameters sin2 θ12, sin2 θ13 and sin2 θ23, taking into account their respective 3σ uncertainties, are successfully reproduced.
Leptonic Dirac CP violation predictions from residual discrete symmetries
Directory of Open Access Journals (Sweden)
I. Girardi
2016-01-01
Full Text Available Assuming that the observed pattern of 3-neutrino mixing is related to the existence of a (lepton flavour symmetry, corresponding to a non-Abelian discrete symmetry group Gf, and that Gf is broken to specific residual symmetries Ge and Gν of the charged lepton and neutrino mass terms, we derive sum rules for the cosine of the Dirac phase δ of the neutrino mixing matrix U. The residual symmetries considered are: i Ge=Z2 and Gν=Zn, n>2 or Zn×Zm, n,m≥2; ii Ge=Zn, n>2 or Zn×Zm, n,m≥2 and Gν=Z2; iii Ge=Z2 and Gν=Z2; iv Ge is fully broken and Gν=Zn, n>2 or Zn×Zm, n,m≥2; and v Ge=Zn, n>2 or Zn×Zm, n,m≥2 and Gν is fully broken. For given Ge and Gν, the sum rules for cosδ thus derived are exact, within the approach employed, and are valid, in particular, for any Gf containing Ge and Gν as subgroups. We identify the cases when the value of cosδ cannot be determined, or cannot be uniquely determined, without making additional assumptions on unconstrained parameters. In a large class of cases considered the value of cosδ can be unambiguously predicted once the flavour symmetry Gf is fixed. We present predictions for cosδ in these cases for the flavour symmetry groups Gf=S4, A4, T′ and A5, requiring that the measured values of the 3-neutrino mixing parameters sin2θ12, sin2θ13 and sin2θ23, taking into account their respective 3σ uncertainties, are successfully reproduced.
Restoring broken entanglement by injecting separable correlations
Pirandola, Stefano
2012-01-01
The distribution of entanglement is central in many protocols of quantum information and computation. However it is also known to be a very fragile process when loss and noise come into play. The inevitable interaction of the quantum systems with the external environment induces effects of decoherence which may be so strong to destroy any input entanglement, a phenomenon known as "entanglement breaking". Here we study this catastrophic process in a correlated-noise environment showing how the presence of classical-type correlations can restore the distribution of entanglement. In particular, we consider a Gaussian environment whose thermal noise is strong enough to break the entanglement of two bosonic modes of the electromagnetic field. In this scenario, we show that the injection of separable correlations from the same environment is able to reactivate the broken entanglement. This paradoxical effect happens both in schemes of direct distribution, where a third party (Charlie) broadcasts entangled states to...
Effective Action of Softly Broken Supersymmetric Theories
Nibbelink, S G; Nibbelink, Stefan Groot; Nyawelo, Tino S.
2007-01-01
We study the renormalization of (softly) broken supersymmetric theories at the one loop level in detail. We perform this analysis in a superspace approach in which the supersymmetry breaking interactions are parameterized using spurion insertions. We comment on the uniqueness of this parameterization. We compute the one loop renormalization of such theories by calculating superspace vacuum graphs with multiple spurion insertions. To preform this computation efficiently we develop algebraic properties of spurion operators, that naturally arise because the spurions are often surrounded by superspace projection operators. Our results are general apart from the restrictions that higher super covariant derivative terms and some finite effects due to non-commutativity of superfield dependent mass matrices are ignored. One of the soft potentials induces renormalization of the Kaehler potential.
Polynomial Graphs and Symmetry
Goehle, Geoff; Kobayashi, Mitsuo
2013-01-01
Most quadratic functions are not even, but every parabola has symmetry with respect to some vertical line. Similarly, every cubic has rotational symmetry with respect to some point, though most cubics are not odd. We show that every polynomial has at most one point of symmetry and give conditions under which the polynomial has rotational or…
Polynomial Graphs and Symmetry
Goehle, Geoff; Kobayashi, Mitsuo
2013-01-01
Most quadratic functions are not even, but every parabola has symmetry with respect to some vertical line. Similarly, every cubic has rotational symmetry with respect to some point, though most cubics are not odd. We show that every polynomial has at most one point of symmetry and give conditions under which the polynomial has rotational or…
Modified broken rice starch as fat substitute in sausages
Directory of Open Access Journals (Sweden)
Valéria Maria Limberger
2011-09-01
Full Text Available The demand for low-fat beef products has led the food industry to use fat substitutes such as modified starch. About 14% of broken rice is generated during processing. Nevertheless, this by-product contains high levels of starch; being therefore, great raw material for fat substitution. This study evaluated the applicability of chemically and physically modified broken rice starch as fat substitute in sausages. Extruded and phosphorylated broken rice was used in low-fat sausage formulation. All low-fat sausages presented about 55% reduction in the fat content and around 28% reduction in the total caloric value. Fat replacement with phosphorylated and extruded broken rice starch increased the texture acceptability of low-fat sausages, when compared to low-fat sausages with no modified broken rice. Results suggest that modified broken rice can be used as fat substitute in sausage formulations, yielding lower caloric value products with acceptable sensory characteristics.
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)
Effects of broken affordance on visual extinction.
Wulff, Melanie; Humphreys, Glyn W
2015-01-01
Previous studies have shown that visual extinction can be reduced if two objects are positioned to "afford" an action. Here we tested if this affordance effect was disrupted by "breaking" the affordance, i.e., if one of the objects actively used in the action had a broken handle. We assessed the effects of broken affordance on recovery from extinction in eight patients with right hemisphere lesions and left-sided extinction. Patients viewed object pairs that were or were not commonly used together and that were positioned for left- or right-hand actions. In the unrelated pair conditions, either two tools or two objects were presented. In line with previous research (e.g., Riddoch et al., 2006), extinction was reduced when action-related object pairs and when unrelated tool pairs were presented compared to unrelated object pairs. There was no significant difference in recovery rate between action-related (object-tool) and unrelated tool pairs. In addition, performance with action-related objects decreased when the tool appeared on the ipsilesional side compared to when it was on the contralesional side, but only when the tool handle was intact. There were minimal effects of breaking the handle of an object rather than a tool, and there was no effect of breaking the handle on either tools or objects on single item trials. The data suggest that breaking the handle of a tool lessens the degree to which it captures attention, with this attentional capture being strongest when the tool appears on the ipsilesional side. The capture of attention by the ipsilesional item then reduces the chance of detecting the contralesional stimulus. This attentional capture effect is mediated by the affordance to the intact tool.
Effects of broken affordance on visual extinction
Directory of Open Access Journals (Sweden)
Melanie eWulff
2015-09-01
Full Text Available Previous studies have shown that visual extinction can be reduced if two objects are positioned to afford an action. Here we tested if this affordance effect was disrupted by breaking the affordance – if one of the objects actively used in the action had a broken handle. We assessed the effects of broken affordance on recovery from extinction in eight patients with right hemisphere lesions and left-sided extinction. Patients viewed object pairs that were or were not commonly used together and that were positioned for left- or right-hand actions. In the unrelated pair conditions, either two tools or two objects were presented. In line with previous research (e.g., Riddoch et al., 2006, extinction was reduced when action-related object pairs and when unrelated tool pairs were presented compared to unrelated object pairs. There was no significant difference in recovery rate between action-related (object-tool and unrelated tool-tool pairs. In addition, performance with action-related objects decreased when the tool appeared on the ipsilesional side compared to when it was on the contralesional side, but only when the tool handle was intact. There were minimal effects of breaking the handle of an object rather than a tool, and there was no effect of breaking the handle on either tools or objects on single item trials. The data suggest that breaking the handle of a tool lessens the degree to which it captures attention, with this attentional capture being strongest when the tool appears on the ipsilesional side. The capture of attention by the ipsilesional item then reduces the chance of detecting the contralesional stimulus. This attentional capture effect is mediated by the affordance to the intact tool.
Symmetry properties with pupil phase-filters.
Ledesma, Silvia; Campos, J; Escalera, J; Yzuel, M
2004-05-31
Pupil filters can modify the three dimensional response of an optical system. In this paper, we study different pupil symmetries that produce a predictable image behavior. We show that different pupil-filters that satisfy certain symmetry conditions can produce axial responses which are either identical or mirror reflected. We also establish the differences in the symmetry properties between amplitude-only filters and phase-only filters. In particular, we are interested in phase filters that produce transverse superresolution with axial superresolution or high depth of focus.
Blanco, Celia; Crusats, Joaquim; El-Hachemi, Zoubir; Moyano, Albert; Hochberg, David; 10.1039/C2CP43488A
2012-01-01
We analyze limited enantioselective (LES) autocatalysis in a temperature gradient and with internal flow/recycling of hot and cold material. Microreversibility forbids broken mirror symmetry for LES in the presence of a temperature gradient alone. This symmetry can be broken however when the auto-catalysis and limited enantioselective catalysis are each localized within the regions of low and high temperature, respectively. This scheme has been recently proposed as a plausible model for spontaneous emergence of chirality in abyssal hydrothermal vents. Regions in chemical parameter space are mapped out in which the racemic state is unstable and bifurcates to chiral solutions.
Test of Lorentz symmetry with trapped ions
Pruttivarasin, Thaned
2016-05-01
The outcome of an experiment should not depend on the orientation of the apparatus in space. This important cornerstone of physics is deeply engrained into the Standard Model of Physics by requiring that all fields must be Lorentz invariant. However, it is well-known that the Standard Model is incomplete. Some theories conjecture that at the Planck scale Lorentz symmetry might be broken and measurable at experimentally accessible energy scales. Therefore, a search for violation of Lorentz symmetry directly probes physics beyond the Standard model. We present a novel experiment utilizing trapped calcium ions as a direct probe of Lorentz-violation in the electron-photon sector. We monitor the energy between atomic states with different orientations of the electronic wave-functions as they rotate together with the motion of the Earth. This is analogous to the famous Michelson-Morley experiment. To remove magnetic field noise, we perform the experiment with the ions prepared in the decoherence-free states. Our result improves on the most stringent bounds on Lorentz symmetry for electrons by 100 times. The experimental scheme is readily applicable to many ion species, hence opening up paths toward much improved test of Lorentz symmetry in the future. (Ph. D. Advisor: Hartmut Haeffner, University of California, Berkeley).
Flavor Symmetry and Vacuum Aligned Mass Textures
Kaneko, S; Shingai, T; Tanimoto, M; Yoshioka, K; Kaneko, Satoru; Sawanaka, Hideyuki; Shingai, Takaya; Tanimoto, Morimitsu; Yoshioka, Koichi
2007-01-01
The mass matrix forms of quarks and leptons are discussed in theory with permutation flavor symmetry. The structure of scalar potential is analyzed in case that electroweak doublet Higgs fields have non-trivial flavor symmetry charges. We find that realistic forms of mass matrices are obtained dynamically in the vacuum of the theory, where some of Higgs bosons have vanishing expectation values which lead to vanishing elements in quark and lepton mass matrices. Mass textures are realized in the true vacuum and their positions are controlled by flavor symmetry. An interesting point is that, due to the flavor group structure, the up and down quark mass matrices are automatically made different in the vacuum, which lead to non-vanishing generation mixing. It is also discussed that flavor symmetry is needed to be broken in order not to have too light scalars. The lower bounds of Higgs masses are derived from the experimental data of flavor-changing rare processes such as the neutral K meson mixing.
Tri-Bimaximal Mixing from Twisted Friedberg-Lee Symmetry
Araki, Takeshi
2008-01-01
We consider the tri-bimaximal generation mixing in terms of the Friedberg-Lee (FL) symmetry. The symmetry is a kind of translational one for the fermion field operators. The symmetry with uniform translation for each generation of neutrinos can partially realize the desired form of the neutrino mass matrix for the tri-bimaximal mixing but should be improved to obtain the experimentally favored neutrino mass spectrum. It is firstly pointed out that patterns of the uniformity breaking are important for resulting form of the neutrino mass matrix. Then we propose a promotion of the FL symmetry to have the $\\mu - \\tau$ one, and call that the twisted FL symmetry. Based on the twisted FL symmetry, two possible schemes are also presented toward the realistic neutrino mass spectrum and the tri-bimaximal mixing. The first possible scheme is that the uniformity of the FL symmetry is broken by terms preserving the twisted FL one. The second one is based on the $S_3$ permutation family symmetry. The breaking terms, which ...
Majorana neutrino masses from anomalous U(1) symmetries
Energy Technology Data Exchange (ETDEWEB)
Leontaris, G.K. [Theoretical Physics Division, University of Ioannina, GR-45110 Ioannina (Greece)]. E-mail: leonta@artemis1.physics.uoi.gr; Rizos, J. [Theoretical Physics Division, University of Ioannina, GR-45110 Ioannina (Greece); Psallidas, A. [Theoretical Physics Division, University of Ioannina, GR-45110 Ioannina (Greece)
2004-09-09
We explore the possibility of interpreting the solar and atmospheric neutrino data within the context of the Minimal Supersymmetric Standard Model augmented by a single U(1) anomalous family symmetry spontaneously broken by non-zero vacuum expectation values of a pair of singlet fields. The symmetry retains a dimension-five operator which provides Majorana masses for left-handed neutrino states. Assuming symmetric lepton mass matrices, the model predicts inverse hierarchical neutrino mass spectrum, {theta}13=0 and large mixing while at the same time it provides acceptable mass matrices for the charged fermions.
Density driven symmetry breaking and Butterfly effect in holographic superconductors
Kim, Youngman; Sin, Sang-Jin
2009-01-01
We study the density driven symmetry breaking in holographic superconductors by considering positive mass squared case. We show that with small values of positive $m^2$, scalar condensation still forms. As $m^2$ increases, however, the phase space folds due to the non-linearity of the equation of motion, and two nearby points in phase space can represent symmetry broken and unbroken configurations respectively, leading to an analogue of the butterfly effect. We also calculate the specific heat and electrical conductivity for various $m^2$ and compare them with experimentally observed numbers in condensed matter systems.
Spontaneous R-symmetry breaking from the renormalization group flow
Amariti, Antonio
2012-01-01
We propose a mechanism of R-symmetry breaking in four-dimensional DSB models based on the RG properties of the coupling constants. By constraining the UV sector, we generate new hierarchies amongst the couplings that allow a spontaneously broken R-symmetry in models with pure chiral fields of R-charges R = 0 and R = 2 only. The result is obtained by a combination of one- and two-loop effects, both at the origin of field space and in the region dominated by leading log potentials.
Applications of flavor symmetry to the phenomenology of elementary particles
Energy Technology Data Exchange (ETDEWEB)
Kaeding, T.A. [Lawrence Berkeley Lab., CA (United States)
1995-05-01
Some applications of flavor symmetry are examined. Approximate flavor symmetries and their consequences in the MSSM (Minimal Supersymmetric Standard Model) are considered, and found to give natural values for the possible B- and L-violating couplings that are empirically acceptable, except for the case of proton decay. The coupling constants of SU(3) are calculated and used to parameterize the decays of the D mesons in broken flavor SU(3). The resulting couplings are used to estimate the long-distance contributions to D-meson mixing.
Disordered d-wave superconductors with chiral symmetry
Fukui, T.
1999-01-01
A two-dimensional lattice model for d-wave superconductor with chiral symmetry is studied. The field theory at the band center is shown to be in the universality class of U(2n)/O(2n) and U(2n) nonlinear sigma model for the system with broken and unbroken time-reversal symmetry, respectively. Vanishing of the beta function implies extended states at the band center. Density of state vanishes as a cubic function of the energy at the band center for the former case, while linear for the latter.
Nonreciprocal transmission in a nonlinear photonic-crystal Fano structure with broken symmetry
DEFF Research Database (Denmark)
Yu, Yi; Chen, Yaohui; Hu, Hao;
2015-01-01
Nanostructures that feature nonreciprocal light trans- mission are highly desirable building blocks for realizing photonic integrated circuits. Here, a simple and ultracompact photonic-crystal structure, where a waveguide is coupled to a single nanocavity, is proposed and experimentally demon- st...... tunability. The nonlinearity of the device relies on ultrafast carrier dynamics, rather than the thermal effects usually considered, allowing the demonstration of nonreciprocal operation at a bit-rate of 10 Gbit s − 1 with a low energy consumption of 4.5 fJ bit − 1...
Campbell, Ian M; Stewart, Jonathan R; James, Regis A; Lupski, James R; Stankiewicz, Paweł; Olofsson, Peter; Shaw, Chad A
2014-10-02
Most new mutations are observed to arise in fathers, and increasing paternal age positively correlates with the risk of new variants. Interestingly, new mutations in X-linked recessive disease show elevated familial recurrence rates. In male offspring, these mutations must be inherited from mothers. We previously developed a simulation model to consider parental mosaicism as a source of transmitted mutations. In this paper, we extend and formalize the model to provide analytical results and flexible formulas. The results implicate parent of origin and parental mosaicism as central variables in recurrence risk. Consistent with empirical data, our model predicts that more transmitted mutations arise in fathers and that this tendency increases as fathers age. Notably, the lack of expansion later in the male germline determines relatively lower variance in the proportion of mutants, which decreases with paternal age. Subsequently, observation of a transmitted mutation has less impact on the expected risk for future offspring. Conversely, for the female germline, which arrests after clonal expansion in early development, variance in the mutant proportion is higher, and observation of a transmitted mutation dramatically increases the expected risk of recurrence in another pregnancy. Parental somatic mosaicism considerably elevates risk for both parents. These findings have important implications for genetic counseling and for understanding patterns of recurrence in transmission genetics. We provide a convenient online tool and source code implementing our analytical results. These tools permit varying the underlying parameters that influence recurrence risk and could be useful for analyzing risk in diverse family structures.
Control the polarization state of light with symmetry-broken metallic metastructures
Energy Technology Data Exchange (ETDEWEB)
Xiong, Xiang, E-mail: xiang@nju.edu.cn; Jiang, Shang-Chi; Hu, Yuan-Sheng; Hu, Yu-Hui; Wang, Zheng-Han; Peng, Ru-Wen; Wang, Mu, E-mail: muwang@nju.edu.cn
2015-07-15
Controlling the polarization state, the transmission direction, the amplitude and the phase of light in a very limited space is essential for the development of on-chip photonics. Over the past decades, numerous sub-wavelength metallic microstructures have been proposed and fabricated to fulfill these demands. In this article, we review our efforts in achieving negative refractive index, controlling the polarization state, and tuning the amplitude of light with two-dimensional (2D) and three-dimensional (3D) microstructures. We designed an assembly of stacked metallic U-shaped resonators that allow achieving negative refraction for pure magnetic and electric responses respectively at the same frequency by selecting the polarization of incident light. Based on this, we tune the permittivity and permeability of the structure, and achieve negative refractive index. Further, by control the excitation and radiation of surface electric current on a number of 2D and 3D asymmetric metallic metastructures, we are able to control the polarization state of light. It is also demonstrated that with a stereostructured metal film, the whole metal surfaces can be used to construct either polarization-sensitive or polarization-insensitive prefect absorbers, with the advantage of efficient heat dissipation and electric conductivity. Our practice shows that metamaterials, including metasurface, indeed help to master light in nanoscale, and are promising in the development of new generation of photonics.
He, Yan; Guo, Hao
2016-07-01
Respecting the conservation laws of momentum and energy in a many body theory is very important for understanding the transport phenomena. The previous conserving approximation requires that the self-energy of a single particle could be written as a functional derivative of a full dressed Green's function. This condition can not be satisfied in the G0 G t-matrix or pair fluctuation theory which emphasizes the fermion pairing with a stronger than the Bardeen-Cooper-Schrieffer (BCS) attraction. In the previous work [1], we have shown that when the temperature is above the superfluid transition temperature Tc, the G0 G t-matrix theory can be put into a form that satisfies the stress tensor Ward identity (WI) or local form of conservation laws by introducing a new type of vertex correction. In this paper, we will extend the above conservation approximation to the superfluid phase in the BCS mean field level. To establish the stress tensor WI, we have to include the fluctuation of the order parameter or the contribution from the Goldstone mode. The result will be useful for understanding the transport properties such as the behavior of the viscosity of Fermionic gases in the superfluid phases.
Broken Symmetry in the Elastic Response to Temperature of Consolidated Granular Media
Ulrich, T. J.
2006-05-01
When subjected to externally applied forces consolidated granular media (CGM), take a Berea sandstone as example, are elastically soft, unusually nonlinear, and have hysteresis with end point memory. In response to a variety of transient external disturbances CGM exhibit slow dynamics, e.g. log(t) recovery of the strain following a step change in applied pressure. These elastic properties have led to a bricks (sand grains) and mortar (bond system) picture to describe the physics of the system. Because the grains are thermally anisotropic, temperature drives the bond system altogether differently than applied stress. Consequently temperature provides the means to probe new features in the elastic response of CGM. I describe an experiment/analysis in which the temperature, used to probe the elastic state of a CGM, reveals unusual behavior. The elastic state of CGM at fixed applied stress and temperature, is a function of the applied stress protocol and the temperature protocol. Working at constant stress I find that all aspects of the elastic response to temperature exhibit behavior which presents a broad range of time scales, i.e. slow dynamics, and the response to a transient temperature disturbance is asymmetric in the sign of ΔT(t).
Universal bounds on efficiency and power of heat engines with broken time-reversal symmetry
2015-01-01
Ever since James Watt's steam engine, the urge to explore the fundamental principles governing the performance of devices that convert thermal energy into useful work was one of the major quests in thermodynamics. From a conceptual point of view, such heat engines can be divided into two classes. Cyclic engines use a reciprocating piston to generate mechanical work by periodically compressing and expanding a working fluid at varying temperature. Thermoelectric engines consist of two heat and ...
Investigation of broken symmetry of Sb/Cu(111) surface alloys by VT-STM
CSIR Research Space (South Africa)
Ndlovu, GF
2011-07-01
Full Text Available This work present an in situ Variable Temperature Scanning Tunneling Microscopy (VT-STM) study of the Sb/Cu(111) system studied at various temperatures. The experimental data support a structural model in which Sb atoms displace up to 1...
Directory of Open Access Journals (Sweden)
Metag Volker
2014-01-01
Full Text Available Chiral symmetry is a fundamental symmetry of Quantum Chromodynamics (QCD in the limit of vanishing quark masses. In the hadronic sector chiral symmetry is broken; otherwise chiral partners - hadronic states with the same spin but opposite parity - should be degenerate in mass which is not observed in nature. It has been suggested that chiral symmetry might at least be partially restored in a strongly interacting environment. As a consequence, properties of hadrons, encoded in their mass and width, may be modified when embedded in a nucleus. These ideas have motivated widespread theoretical and experimental activities. As an example, recent experimental results on the in-medium properties of the η′ meson are presented.
Logotherapy Counseling to Improve Acceptance of Broken Home Child
Directory of Open Access Journals (Sweden)
Erwin Erlangga
2017-08-01
Full Text Available This study aims to increase the enrollment of children of a broken home that life has meaning. Subjects are 100 children in Demak whose families experiencing divorce. Research themes include three things: individual counseling, engineering logotherapy, reception, and a child of a broken home. Data obtained based on interviews, observation, and psychological scale showed that of the 100 children of a broken home has a low acceptance that individual counseling with logotherapy techniques were considered appropriate to increase the enrollment of children of a broken home. Factors - factors that affect the acceptance of a child of a broken home is self-blame, anger and did not have a purpose in life again. In addition the environment is also a significant effect on the enrollment of children of a broken home. Environmental labeling of families experiencing divorce as a family that failed so that children are increasingly stressed with the stamp of the community. Based on the field test results, the level of acceptance of the child of a broken home increases after the individual is given counseling services with logotherapy techniques. Indicated by changes in the level of acceptance of children of a broken home before being given treatment (initial evaluation and after (final evaluation of 130 points. The results of effectiveness test statistic t test calculations also showed 0,010 <0.05.It was concluded that counseling individuals with logotherapy effective technique to increase the enrollment of children of a broken home
Bouwknegt, P G
1995-01-01
W-symmetry is an extension of conformal symmetry in two dimensions. Since its introduction in 1985, W-symmetry has become one of the central notions in the study of two-dimensional conformal field theory. The mathematical structures that underlie W-symmetry are so-called W-algebras, which are higher-spin extensions of the Virasoro algebra. This book contains a collection of papers on W-symmetry, covering the period from 1985 through 1993. Its main focus is the construction of W-algebras and their representation theory. A recurrent theme is the intimate connection between W-algebras and affine
Symmetry restoration at finite temperature with weak magnetic fields
Navarro, Jorge; Tejeda-Yeomans, Maria Elena; Ayala, Alejandro; Piccinelli, Gabriella
2010-01-01
We study symmetry restoration at finite temperature in the standard model during the electroweak phase transition in the presence of a weak magnetic field. We compute the finite temperature effective potential up to the contribution of ring diagrams, using the broken phase degrees of freedom, and keep track of the gauge parameter dependence of the results. We show that under these conditions, the phase transition becomes stronger first order.
Dynamical symmetry breaking with hypercolour and high colour representations
Energy Technology Data Exchange (ETDEWEB)
Zoupanos, G.
1985-03-01
A model is presented in which the electroweak gauge group is spontaneously broken according to a dynamical scenario based on the existence of high colour representations. An unattractive feature of this scenario was the necessity to introduce elementary Higgs fields in order to obtain the spontaneous symmetry breaking of part of the theory. In the present model, this breaking can also be understood dynamically with the introduction of hypercolour interactions.
Breaking of forward-backward symmetry in driven systems
DEFF Research Database (Denmark)
Szolnoki, Attila; Szabó, György
1993-01-01
The dynamical pair approximation was modified to study the stationary states in a two-dimensional repulsive-lattice-gas model driven far from equilibrium by the application of an external field. This approximation distinguishes between the forward, backward, and transverse directions with respect...... to the electric field. In the present driven system, the forward-backward symmetry is broken at the level of the pair approximation. The difference between the forward and backward directions is confirmed by Monte Carlo simulations....
Spontaneous Symmetry Breaking and Nambu–Goldstone Bosons in Quantum Many-Body Systems
Directory of Open Access Journals (Sweden)
Tomáš Brauner
2010-04-01
Full Text Available Spontaneous symmetry breaking is a general principle that constitutes the underlying concept of a vast number of physical phenomena ranging from ferromagnetism and superconductivity in condensed matter physics to the Higgs mechanism in the standard model of elementary particles. I focus on manifestations of spontaneously broken symmetries in systems that are not Lorentz invariant, which include both nonrelativistic systems as well as relativistic systems at nonzero density, providing a self-contained review of the properties of spontaneously broken symmetries specific to such theories. Topics covered include: (i Introduction to the mathematics of spontaneous symmetry breaking and the Goldstone theorem. (ii Minimization of Higgs-type potentials for higher-dimensional representations. (iii Counting rules for Nambu–Goldstone bosons and their dispersion relations. (iv Construction of effective Lagrangians. Specific examples in both relativistic and nonrelativistic physics are worked out in detail.
Ovchinnikov, Igor V
2012-01-01
Here it is shown that the most general Parisi-Sourlas-Wu stochastic quantization procedure applied to any stochastic differential equation (SDE) leads to a Witten-type topological field theory - a model with a global topological Becchi-Rouet-Stora-Tyutin supersymmetry (Q-symmetry). Q-symmetry can be dynamically broken only by (anti-)instantons - ultimately nonlinear sudden tunneling processes of (creation)annihilation of solitons, e.g., avalanches in self-organized criticality (SOC) or (creation)annihilation of vortices in turbulent water. The phases with unbroken Q-symmetry are essentially markovian and can be understood solely in terms of the conventional Fokker-Plank evolution of the probability density. For these phases, Ito interpretation of SDEs and/or Martin-Siggia-Rose approximation of the stochastic quantization are applicable. SOC, turbulence, glasses, quenches etc. constitute the "generalized turbulence" category of stochastic phases with broken Q-symmetry. In this category, (anti-)instantons conde...
Wang, Zhi-Wei; Steele, T G; Mann, R B; Hanif, T
2016-01-01
We consider a conformal complex singlet extension of the Standard Model with a Higgs portal interaction. Two different scenarios depending on whether the global U(1) symmetry is broken or not have been studied. In the unbroken phase, the decay of the complex singlet is protected by the global U(1) symmetry which leads to an ideal cold dark matter candidate. In the broken phase, we are able to provide a second Higgs at $554\\,\\rm{GeV}$. In addition, gauging the global U(1) symmetry, we can construct an asymptotically safe U(1)' leptophobic model. We combine the notion of asymptotic safety with conformal symmetry and use the renormalization group equations as a bridge to connect UV boundary conditions and Electroweak/ TeV scale physics. We also provide a detailed example to show that these boundary conditions will lead to phenomenological signatures such as diboson excesses which could be tested at the LHC.
The wave has finally broken: now what?
Simborg, Donald W; Detmer, Don Eugene; Berner, Eta S
2013-06-01
In 2005, the authors published a paper, 'Will the wave finally break? A brief view of the adoption of electronic medical records in the United States', which predicted that rapid adoption of electronic health records (EHR) would occur in the next 5 years given appropriate incentives. The wave has finally broken with the stimulus of the health information technology for economic and clinical health legislation in 2009, and there have been both positive and negative developments in the ensuing years. The positive developments, among others described, are increased adoption of EHR, the emergence of a national network infrastructure and the recognition of clinical informatics as a medical specialty. Problems that still exist include, among others described, continued user interface problems, distrust of EHR-generated notes and an increased potential for fraud and abuse. It is anticipated that in the next 5 years there will be near universal EHR adoption, greater emphasis on standards and interoperability, greater involvement of Congress in health information technology (IT), breakthroughs in user interfaces, compelling online medical and IT education, both increased use of data analytics for personalized healthcare and a realization of the difficulties of this approach, a blurring of the distinction between EHR and telemedicine, a resurgence of computer-assisted diagnosis and the emergence of a 'continuously learning' healthcare system.
Planck driven by vision, broken by war
Brown, Brandon R
2015-01-01
Planck's Law, an equation used by physicists to determine the radiation leaking from any object in the universe, was described by Albert Einstein as "the basis of all twentieth-century physics." Max Planck is credited with being the father of quantum theory, and his work laid the foundation for our modern understanding of matter and energetic processes. But Planck's story is not well known, especially in the United States. A German physicist working during the first half of the twentieth century, his library, personal journals, notebooks, and letters were all destroyed with his home in World War II. What remains, other than his contributions to science, are handwritten letters in German shorthand, and tributes from other scientists of the time, including his close friend Albert Einstein. In Planck: Driven by Vision, Broken by War, Brandon R. Brown interweaves the voices and writings of Planck, his family, and his contemporaries-with many passages appearing in English for the first time-to create a portrait of...
Uniform trace formulae for SU(2) and SO(3) symmetry breaking
Brack, M; Tanaka, K
1999-01-01
We develop uniform approximations for the trace formula for non-integrable systems in which SU(2) symmetry is broken by a non-linear term of the Hamiltonian. As specific examples, we investigate Hénon-Heiles type potentials. Our formalism can also be applied to the breaking of SO(3) symmetry in a three-dimensional cavity with axially-symmetric quadrupole deformation.
Partial dynamical symmetry as a selection criterion for many-body interactions
Leviatan, A; Van Isacker, P
2013-01-01
We propose the use of partial dynamical symmetry (PDS) as a selection criterion for higher-order terms in situations when a prescribed symmetry is obeyed by some states and is strongly broken in others. The procedure is demonstrated in a first systematic classification of many-body interactions with SU(3) PDS that can improve the description of deformed nuclei. As an example, the triaxial features of the nucleus 156Gd are analyzed.
ON THE NOETHER SYMMETRY AND LIE SYMMETRY OF MECHANICAL SYSTEMS
Institute of Scientific and Technical Information of China (English)
梅凤翔; 郑改华
2002-01-01
The Noether symmetry is an invariance of Hamilton action under infinitesimal transformations of time and the coordinates. The Lie symmetry is an invariance of the differential equations of motion under the transformations. In this paper, the relation between these two symmetries is proved definitely and firstly for mechanical systems. The results indicate that all the Noether symmetries are Lie symmetries for Lagrangian systems meanwhile a Noether symmetry is a Lie symmetry for the general holonomic or nonholonomic systems provided that some conditions hold.
Energy Technology Data Exchange (ETDEWEB)
Kurkov, Maxim A. [Universidade Federal do ABC, CMCC, Santo Andre, SP (Brazil)
2016-06-15
We study effects of a rippling gravitational background on a scalar field with a double well potential, focusing on the analogy with the well known dynamics of the Kapitza's pendulum. The ripples are rendered as infinitesimal but rapidly oscillating perturbations of the scale factor. We find that the resulting dynamics crucially depends on a value of the parameter ξ in the ξRφ{sup 2} vertex. For the time-dependent perturbations of a proper form the resulting effective action is generally covariant, and at a high enough frequency at ξ < 0 and at ξ > 1/6 the effective potential has a single minimum at zero, thereby restoring spontaneously broken symmetry of the ground state. On the other side, at 0 < ξ < 1/6 spontaneous symmetry breaking emerges even when it is absent in the unperturbed case. (orig.)
Insulators and metals with topological order and discrete symmetry breaking
Chatterjee, Shubhayu; Sachdev, Subir
2017-05-01
Numerous experiments have reported discrete symmetry breaking in the high-temperature pseudogap phase of the hole-doped cuprates, including breaking of one or more of lattice rotation, inversion, and time-reversal symmetries. In the absence of translational symmetry breaking or topological order, these conventional order parameters cannot explain the gap in the charged fermion excitation spectrum in the antinodal region. Zhao et al. [L. Zhao, D. H. Torchinsky, H. Chu, V. Ivanov, R. Lifshitz, R. Flint, T. Qi, G. Cao, and D. Hsieh, Nat. Phys. 12, 32 (2016), 10.1038/nphys3517] and Jeong et al. [J. Jeong, Y. Sidis, A. Louat, V. Brouet, and P. Bourges, Nat. Commun. 8, 15119 (2017), 10.1038/ncomms15119] have also reported inversion and time-reversal symmetry breaking in insulating Sr2IrO4 similar to that in the metallic cuprates, but coexisting with Néel order. We extend an earlier theory of topological order in insulators and metals, in which the topological order combines naturally with the breaking of these conventional discrete symmetries. We find translationally invariant states with topological order coexisting with both Ising-nematic order and spontaneous charge currents. The link between the discrete broken symmetries and the topological-order-induced pseudogap explains why the broken symmetries do not survive in the confining phases without a pseudogap at large doping. Our theory also connects to the O(3) nonlinear sigma model and CP1 descriptions of quantum fluctuations of the Néel order. In this framework, the optimal doping criticality of the cuprates is primarily associated with the loss of topological order.
From physical symmetries to emergent gauge symmetries
Energy Technology Data Exchange (ETDEWEB)
Barceló, Carlos [Instituto de Astrofísica de Andalucía (IAA-CSIC),Glorieta de la Astronomía, 18008 Granada (Spain); Carballo-Rubio, Raúl [Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía, 18008 Granada (Spain); Laboratory for Quantum Gravity & Strings,Department of Mathematics & Applied Mathematics, University of Cape Town,Private Bag, Rondebosch 7701 (South Africa); Di Filippo, Francesco [Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía, 18008 Granada (Spain); Dipartamento di Scienze Fisiche “E.R. Caianiello”, Università di Salerno,I-84081 Fisciano (Italy); Garay, Luis J. [Departamento de Física Teórica II, Universidad Complutense de Madrid, 28040 Madrid (Spain); Instituto de Estructura de la Materia (IEM-CSIC), Serrano 121, 28006 Madrid (Spain)
2016-10-17
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 gravity program, such as the Weinberg-Witten theorem, are discussed.
From physical symmetries to emergent gauge symmetries
Barceló, Carlos; Carballo-Rubio, Raúl; Di Filippo, Francesco; Garay, Luis J.
2016-10-01
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 gravity program, such as the Weinberg-Witten theorem, are discussed.
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...
Symmetries in fluctuations far from equilibrium.
Hurtado, Pablo I; Pérez-Espigares, Carlos; del Pozo, Jesús J; Garrido, Pedro L
2011-05-10
Fluctuations arise universally in nature as a reflection of the discrete microscopic world at the macroscopic level. Despite their apparent noisy origin, fluctuations encode fundamental aspects of the physics of the system at hand, crucial to understand irreversibility and nonequilibrium behavior. To sustain a given fluctuation, a system traverses a precise optimal path in phase space. Here we show that by demanding invariance of optimal paths under symmetry transformations, new and general fluctuation relations valid arbitrarily far from equilibrium are unveiled. This opens an unexplored route toward a deeper understanding of nonequilibrium physics by bringing symmetry principles to the realm of fluctuations. We illustrate this concept studying symmetries of the current distribution out of equilibrium. In particular we derive an isometric fluctuation relation that links in a strikingly simple manner the probabilities of any pair of isometric current fluctuations. This relation, which results from the time-reversibility of the dynamics, includes as a particular instance the Gallavotti-Cohen fluctuation theorem in this context but adds a completely new perspective on the high level of symmetry imposed by time-reversibility on the statistics of nonequilibrium fluctuations. The new symmetry implies remarkable hierarchies of equations for the current cumulants and the nonlinear response coefficients, going far beyond Onsager's reciprocity relations and Green-Kubo formulas. We confirm the validity of the new symmetry relation in extensive numerical simulations, and suggest that the idea of symmetry in fluctuations as invariance of optimal paths has far-reaching consequences in diverse fields.
Optimization leads to symmetry
Institute of Scientific and Technical Information of China (English)
Chenghong WANG; Yuqian GUO; Daizhan CHENG
2004-01-01
The science of complexity studies the behavior and properties of complex systems in nature and human society.Particular interest has been put on their certain simple common properties.Symmetry is one of such properties.Symmetric phenomena can be found in many complex systems.The purpose of this paper is to reveal the internal reason of the symmetry.Using some physical systems and geometric objects,the paper shows that many symmetries are caused by optimization under certain criteria.It has also been revealed that an evolutional process may lead to symmetry.
Approximate and renormgroup symmetries
Energy Technology Data Exchange (ETDEWEB)
Ibragimov, Nail H. [Blekinge Institute of Technology, Karlskrona (Sweden). Dept. of Mathematics Science; Kovalev, Vladimir F. [Russian Academy of Sciences, Moscow (Russian Federation). Inst. of Mathematical Modeling
2009-07-01
''Approximate and Renormgroup Symmetries'' deals with approximate transformation groups, symmetries of integro-differential equations and renormgroup symmetries. It includes a concise and self-contained introduction to basic concepts and methods of Lie group analysis, and provides an easy-to-follow introduction to the theory of approximate transformation groups and symmetries of integro-differential equations. The book is designed for specialists in nonlinear physics - mathematicians and non-mathematicians - interested in methods of applied group analysis for investigating nonlinear problems in physical science and engineering. (orig.)
Symmetries in atmospheric sciences
Bihlo, Alexander
2009-01-01
Selected applications of symmetry methods in the atmospheric sciences are reviewed briefly. In particular, focus is put on the utilisation of the classical Lie symmetry approach to derive classes of exact solutions from atmospheric models. This is illustrated with the barotropic vorticity equation. Moreover, the possibility for construction of partially-invariant solutions is discussed for this model. A further point is a discussion of using symmetries for relating different classes of differential equations. This is illustrated with the spherical and the potential vorticity equation. Finally, discrete symmetries are used to derive the minimal finite-mode version of the vorticity equation first discussed by E. Lorenz (1960) in a sound mathematical fashion.
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.
Old nuclear symmetries and large N(c) as long distance symmetries in the two nucleon system
Arriola, E Ruiz
2009-01-01
Wigner and Serber symmetries for the two-nucleon system provide unique examples of long distance symmetries in Nuclear Physics, i.e. symmetries of the meson exchange forces broken only at arbitrarily small distances. We analyze the large Nc picture as a key ingredient to understand these, so far accidental, symmetries from a more fundamental viewpoint. A set of sum rules for NN phase-shifts, NN potentials and coarse grained V_lowk NN potentials can be derived showing Wigner SU(4) and Serber symmetries not to be fully compatible everywhere. The symmetry breaking pattern found from the partial wave analysis data, high quality potentials in coordinate space at long distances and their V_lowk relatives is analyzed on the light of large N(c) contracted SU(4) symmetry. Our results suggest using large Nc potentials as long distance ones for the two-nucleon system where the meson exchange potential picture is justified and known to be consistent with large Nc counting rules. We also show that potentials based on chir...
arXiv Standard Model with spontaneously broken quantum scale invariance
Ghilencea, D.M.; Olszewski, P.
We explore the possibility that scale symmetry is a quantum symmetry that is broken only spontaneously and apply this idea to the Standard Model (SM). We compute the quantum corrections to the potential of the higgs field ($\\phi$) in the classically scale invariant version of the SM ($m_\\phi=0$ at tree level) extended by the dilaton ($\\sigma$). The tree-level potential of $\\phi$ and $\\sigma$, dictated by scale invariance, may contain non-polynomial effective operators, e.g. $\\phi^6/\\sigma^2$, $\\phi^8/\\sigma^4$, $\\phi^{10}/\\sigma^6$, etc. The one-loop scalar potential is scale invariant, since the loop calculations manifestly preserve the scale symmetry, with the DR subtraction scale $\\mu$ generated spontaneously by the dilaton vev $\\mu\\sim\\langle\\sigma\\rangle$. The Callan-Symanzik equation of the potential is verified in the presence of the gauge, Yukawa and the non-polynomial operators. The couplings of the non-polynomial operators have non-zero beta functions that we can actually compute from the quantum po...
Symmetry properties of periodic orbits extracted from scattering data
Merlo, O.; Jung, C.; Seligman, T. H.
2004-12-01
Discrete symmetries of a system are reflected in the properties of the shortest periodic orbits. By applying a recent method to extract these from the scaling of the fractal structure in scattering functions, we show how the symmetries can be extracted from scattering data simultaneously with the periods and the Lyapunov exponents. We pay particular attention to the change of scattering data under a small symmetry breaking.
Clash of symmetries in a Randall-Sundrum-like spacetime
Dando, Gareth; Davidson, Aharon; George, Damien P.; Volkas, Raymond R.; Wali, K. C.
2005-08-01
We present a toy model that exhibits clash-of-symmetries style Higgs field kink configurations in a Randall-Sundrum-like spacetime. The model has two complex scalar fields Φ1,2, with a sextic potential obeying global U(1)⊗U(1) and discrete Φ1↔Φ2 interchange symmetries. The scalar fields are coupled to 4+1 dimensional gravity endowed with a bulk cosmological constant. We show that the coupled Einstein-Higgs field equations have an interesting analytic solution provided the sextic potential adopts a particular form. The 4+1 metric is shown to be that of a smoothed-out Randall-Sundrum type of spacetime. The thin-brane Randall-Sundrum limit, whereby the Higgs field kinks become step functions, is carefully defined in terms of the fundamental parameters in the action. The “clash-of-symmetries” feature, defined in previous papers, is manifested here through the fact that both of the U(1) symmetries are spontaneously broken at all nonasymptotic points in the extra dimension w. One of the U(1)’s is asymptotically restored as w→-∞, with the other U(1) restored as w→+∞. The spontaneously broken discrete symmetry ensures topological stability. In the gauged version of this model we find new flat-space solutions, but in the warped metric case we have been unable to find any solutions with nonzero gauge fields.
Ma, Yong-Liang; Harada, Masayasu; Lee, Hyun Kyu; Oh, Yongseok; Park, Byung-Yoon; Rho, Mannque
2014-08-01
We find that, when the dilaton is implemented as a (pseudo-)Nambu-Goldstone boson using a conformal compensator or "conformon" in a hidden gauge symmetric Lagrangian written to O(p4) from which baryons arise as solitons, namely, skyrmions, the vector manifestation and chiral symmetry restoration at high density predicted in hidden local symmetry theory—which is consistent with Brown-Rho scaling—are lost or sent to infinite density. It is shown that they can be restored if in medium the behavior of the ω field is taken to deviate from that of the ρ meson in such a way that the flavor U(2) symmetry is strongly broken at increasing density. The hitherto unexposed crucial role of the ω meson in the structure of elementary baryon and multibaryon systems is uncovered in this work. In the state of half-skyrmions to which the skyrmions transform at a density n1/2≳n0 (where n0 is the normal nuclear matter density), characterized by the vanishing (space averaged) quark condensate but nonzero pion decay constant, the nucleon mass remains more or less constant at a value ≳60% of the vacuum value, indicating a large component of the nucleon mass that is not associated with the spontaneous breaking of chiral symmetry. We discuss its connection to the chiral-invariant mass m0 that figures in the parity-doublet baryon model.
Spontaneous breaking of the BRST symmetry in presence of the Gribov horizon: renormalizability
Capri, M A L; Guimaraes, M S; Justo, I F; Palhares, L F; Sorella, S P
2013-01-01
An all orders algebraic proof of the multiplicative renormalizability of the novel formulation of the Gribov-Zwanziger action proposed in Phys. Rev. D 86, 045005 (2012) [arXiv:1205.3934], and allowing for an exact but spontaneously broken BRST symmetry, is provided.
Break up of the azimuthal symmetry of higher order fiber modes
DEFF Research Database (Denmark)
Israelsen, Stine Møller; Rishøj, Lars Søgaard; Rottwitt, Karsten
2014-01-01
We investigate Bessel-like modes guided in a double cladding fiber where the outer cladding is an aircladding. For very high order LP0 X-modes, the azimuthal symmetry is broken and the mode is no longer linearly polarized. This is observed experimentally and confirmed numerically. The effect...
Marchis, Iuliana
2009-01-01
Symmetry is one of the fundamental concepts in Geometry. It is a Mathematical concept, which can be very well connected with Art and Ethnography. The aim of the article is to show how to link the geometrical concept symmetry with interculturality. For this mosaics from different countries are used.
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.
Schaft, A.J. van der
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
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...
Spontaneous symmetry breaking in the $S_3$-symmetric scalar sector
Emmanuel-Costa, D.; Osland, P.; Rebelo, M.N.
2016-01-01
We present a detailed study of the vacua of the $S_3$-symmetric three-Higgs-doublet potential, specifying the region of parameters where these minimisation solutions occur. We work with a CP conserving scalar potential and analyse the possible real and complex vacua with emphasis on the cases in which the CP symmetry can be spontaneously broken. Results are presented both in the reducible-representation framework of Derman, and in the irreducible-representation framework. Mappings between these are given. Some of these implementations can in principle accommodate dark matter and for that purpose it is important to identify the residual symmetries of the potential after spontaneous symmetry breakdown. We are also concerned with constraints from vacuum stability.
An SU(5) grand unified model with discrete flavour symmetries
Hernández, A E Cárcamo; Schmidt, Iván
2014-01-01
We propose a model based on the $SU(5)$ grand unification with an extra $Z_{2}\\otimes Z_{2}^{\\prime}\\otimes Z_{2}^{\\prime \\prime}\\otimes Z_{4}\\otimes Z_{12}$ flavor symmetry, which successfully describes the observed SM fermion mass and mixing pattern. The observed quark mass and mixing pattern is caused by the $Z_{4}$ and $Z_{12}$ symmetries, which are broken at very high scale by the $SU(5)$ scalar singlets $\\sigma $ and $\\chi $, charged respectively under these symmetries and which acquire VEVs at the GUT scale. The light neutrino masses are generated via a type I seesaw mechanism with three heavy Majorana neutrinos. The model has in total 17 effective free parameters, from which 2 are fixed and 15 are fitted to reproduce the experimental values of the 18 physical parameters in the quark and lepton sectors. The model predictions for both quark and lepton sectors are in excellent agreement with the experimental data.
Quasiaverages, symmetry breaking and irreducible Green functions method
Directory of Open Access Journals (Sweden)
A.L.Kuzemsky
2010-01-01
Full Text Available The development and applications of the method of quasiaverages to quantum statistical physics and to quantum solid state theory and, in particular, to quantum theory of magnetism, were considered. It was shown that the role of symmetry (and the breaking of symmetries in combination with the degeneracy of the system was reanalyzed and essentially clarified within the framework of the method of quasiaverages. The problem of finding the ferromagnetic, antiferromagnetic and superconducting "symmetry broken" solutions of the correlated lattice fermion models was discussed within the irreducible Green functions method. A unified scheme for the construction of generalized mean fields (elastic scattering corrections and self-energy (inelastic scattering in terms of the equations of motion and Dyson equation was generalized in order to include the "source fields". This approach complements previous studies of microscopic theory of antiferromagnetism and clarifies the concepts of Neel sublattices for localized and itinerant antiferromagnetism and "spin-aligning fields" of correlated lattice fermions.
Explicitly Broken Supersymmetry with Exactly Massless Moduli
Dong, Xi; Zhao, Yue
2014-01-01
There is an avatar of the little hierarchy problem of the MSSM in 3-dimensional supersymmetry. We propose a solution to this problem in AdS$_3$ based on the AdS/CFT correspondence. The bulk theory is a supergravity theory in which U(1) $\\times$ U(1) R-symmetry is gauged by Chern-Simons fields. The bulk theory is deformed by a boundary term quadratic in the gauge fields. It breaks SUSY completely and sources an exactly marginal operator in the dual CFT. SUSY breaking is communicated by gauge interactions to bulk scalar fields and their spinor superpartners. Since the R-charges of scalar and spinor differ, this generates a SUSY breaking shift of their masses. The Ward identity facilitates the calculation of these mass shifts to any desired order in the strength of the deformation. Moduli fields are massless $R$-neutral bulk scalars with vanishing potential in the undeformed theory. These properties are maintained to all orders in the deformation despite the fact that moduli couple in the bulk to loops of R-char...
Explicitly broken supersymmetry with exactly massless moduli
Dong, Xi; Freedman, Daniel Z.; Zhao, Yue
2016-06-01
The AdS/CFT correspondence is applied to an analogue of the little hierarchy problem in three-dimensional supersymmetric theories. The bulk is governed by a super-gravity theory in which a U(1) × U(1) R-symmetry is gauged by Chern-Simons fields. The bulk theory is deformed by a boundary term quadratic in the gauge fields. It breaks SUSY completely and sources an exactly marginal operator in the dual CFT. SUSY breaking is communicated by gauge interactions to bulk scalar fields and their spinor superpartners. The bulk-to-boundary propagator of the Chern-Simons fields is a total derivative with respect to the bulk coordinates. Integration by parts and the Ward identity permit evaluation of SUSY breaking effects to all orders in the strength of the deformation. The R-charges of scalars and spinors differ so large SUSY breaking mass shifts are generated. Masses of R-neutral particles such as scalar moduli are not shifted to any order in the deformation strength, despite the fact that they may couple to R-charged fields running in loops. We also obtain a universal deformation formula for correlation functions under an exactly marginal deformation by a product of holomorphic and anti-holomorphic U(1) currents.
Mei Symmetry and Lie Symmetry of Relativistic Hamiltonian System
Institute of Scientific and Technical Information of China (English)
FANG Jian-Hui; YAN Xiang-Hong; LI Hong; CHEN Pei-Sheng
2004-01-01
The Mei symmetry and the Lie symmetry of the relativistic Hamiltonian system are studied. The definition and criterion of the Mei symmetry and the Lie symmetry of the relativistic Hamiltonian system are given. The relationship between them 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.
Reflection Quasilattices and the Maximal Quasilattice
Boyle, Latham
2016-01-01
We introduce the concept of a {\\it reflection quasilattice}, the quasiperiodic generalization of a Bravais lattice with irreducible reflection symmetry. Among their applications, reflection quasilattices are the reciprocal (i.e. Bragg diffraction) lattices for quasicrystals and quasicrystal tilings, such as Penrose tilings, with irreducible reflection symmetry and discrete scale invariance. In a follow-up paper, we will show that reflection quasilattices can be used to generate tilings in real space with properties analogous to those in Penrose tilings, but with different symmetries and in various dimensions. Here we prove that reflection quasilattices only exist in dimensions two, three and four, and we prove that there is a unique reflection quasilattice in dimension four: the "maximal reflection quasilattice" in terms of dimensionality and symmetry. We further show that, unlike crystallographic Bravais lattices, all reflection quasilattices are invariant under rescaling by certain discrete scale factors. W...
Symmetry Breaking and Adaptation The Genetic Code of Retroviral Env Proteins
Vera, S
1996-01-01
Although several synonymous codons can encode the same aminoacid, this symmetry is generally broken in natural genetic systems. In this article, we show that the symmetry breaking can result from selective pressures due to the violation of the synonym symmetry by mutation and recombination. We conjecture that this enhances the probability to produce mutants that are well-adapted to the current environment. Evidence is found in the codon frequencies of the HIV resistant to the current immunological attack, are found with a greater frequency than their less mutable synonyms.
Spontaneous versus explicit replica symmetry breaking in the theory of disordered systems
Mouhanna, D.; Tarjus, G.
2010-05-01
We investigate the relation between spontaneous and explicit replica symmetry breaking in the theory of disordered systems. On general ground, we prove the equivalence between the replicon operator associated with the stability of the replica-symmetric solution in the standard replica scheme and the operator signaling a breakdown of the solution with analytic field dependence in a scheme in which replica symmetry is explicitly broken by applied sources. This opens the possibility to study, via the recently developed functional renormalization group, unresolved questions related to spontaneous replica symmetry breaking and spin-glass behavior in finite-dimensional disordered systems.
Traces of Lorentz symmetry breaking in a hydrogen atom at ground state
Borges, L. H. C.; Barone, F. A.
2016-02-01
Some traces of a specific Lorentz symmetry breaking scenario in the ground state of the hydrogen atom are investigated. We use standard Rayleigh-Schrödinger perturbation theory in order to obtain the corrections to the ground state energy and the wave function. It is shown that an induced four-pole moment arises, due to the Lorentz symmetry breaking. The model considered is the one studied in Borges et al. (Eur Phys J C 74:2937, 2014), where the Lorentz symmetry is broken in the electromagnetic sector.
Traces of Lorentz symmetry breaking in a Hydrogen atom at ground state
Borges, Luiz Henrique de Campos
2016-01-01
Some traces of a specific Lorentz symmetry breaking scenario in the ground state of the Hydrogen atom are investigated. It is used standard Rayleigh-Schr\\"odinger perturbation theory in order to obtain the corrections to the the ground state energy and wave function. It is shown that an induced four-pole moment arises, due to the Lorentz symmetry breaking. The model considered is the one studied in reference Eur. Phys. J. C {\\bf 74}, 2937 (2014), where the Lorentz symmetry is broken in the electromagnetic sector.
Traces of Lorentz symmetry breaking in a hydrogen atom at ground state
Energy Technology Data Exchange (ETDEWEB)
Borges, L.H.C. [Universidade Federal do ABC, Centro de Ciencias Naturais e Humanas, Santo Andre, SP (Brazil); Barone, F.A. [IFQ-Universidade Federal de Itajuba, Itajuba, MG (Brazil)
2016-02-15
Some traces of a specific Lorentz symmetry breaking scenario in the ground state of the hydrogen atom are investigated. We use standard Rayleigh-Schroedinger perturbation theory in order to obtain the corrections to the ground state energy and the wave function. It is shown that an induced four-pole moment arises, due to the Lorentz symmetry breaking. The model considered is the one studied in Borges et al. (Eur Phys J C 74:2937, 2014), where the Lorentz symmetry is broken in the electromagnetic sector. (orig.)
Interacting spins in a cavity: Finite-size effects and symmetry-breaking dynamics
DEFF Research Database (Denmark)
Gammelmark, Søren; Mølmer, Klaus
2012-01-01
, and for small chains, we find significant and nontrivial finite-size effects. Below the first-order phase transition, even quite large spin chains of 30–40 spins give rise to a mean photon number and number fluctuations significantly above the mean-field vacuum result. Near the second-order phase critical point......-transition the random character of the measurement process causes a measurement-induced symmetry breaking in the system. This symmetry breaking occurs on the time scale needed for an observer to gather sufficient information to distinguish between the two possible (mean-field) symmetry-broken states....
A Note on a Broken-Cycle Theorem for Hypergraphs
Directory of Open Access Journals (Sweden)
Trinks Martin
2014-08-01
Full Text Available Whitney’s Broken-cycle Theorem states the chromatic polynomial of a graph as a sum over special edge subsets. We give a definition of cycles in hypergraphs that preserves the statement of the theorem there
SUSY Moose Runs and Hops: An extra dimension from a broken deformed CFT
Erlich, J; Erlich, Joshua; Tan, Jong Anly
2006-01-01
We find a class of four dimensional deformed conformal field theories which appear extra dimensional when their gauge symmetries are spontaneously broken. The theories are supersymmetric moose models which flow to interacting conformal fixed points at low energies, deformed by superpotentials. Using a-maximization we give strong nonperturbative evidence that the hopping terms in the resulting latticized action are relevant deformations of the fixed point theories. These theories have an intricate structure of RG flows between conformal fixed points. Our results suggest that at the stable fixed points each of the bulk gauge couplings and superpotential hopping terms is turned on, in favor of the extra dimensional interpretation of the theory. However, we argue that the higher dimensional gauge coupling is generically small compared to the size of the extra dimension. In the presence of a brane the topology of the extra dimension is determined dynamically and depends on the numbers of colors and bulk and brane ...
Probing Emergent Scale-Chiral Symmetry in Nuclear Interactions
Paeng, Won-Gi
2016-01-01
In effective field theory for baryonic matter in which broken scale symmetry and hidden local symmetry are incorporated, both scale invariance and local gauge invariance, invisible or perhaps even absent in the QCD vacuum, could arise at high density as emergent symmetries, with a dilaton figuring as a scalar Nambu-Goldstone boson and the $\\rho$ and $a_1$ mesons as gauge fields, the former at the "dialton-limit (DL) fixed point" and the latter at the "vector manifestation (VM) fixed point." A novel phenomenon observed in a simplified model is that the dilaton condensate in nuclear medium "walks" as density increases beyond $n_{1/2}\\sim (2-3)n_0$ and induces the in-medium hidden gauge symmetry coupling, un-scaling up to density $n_{1/2}$, to start dropping rapidly towards the VM fixed point $n_{VM} >n_{1/2} $ at which the vector meson mass vanishes, coinciding, most likely, with chiral symmetry restoration. We discuss how to probe both VM and DL properties by means of the nuclear symmetry energy and the sound ...
Information Content of Spontaneous Symmetry Breaking
Gleiser, Marcelo
2012-01-01
We propose a measure of order in the context of nonequilibrium field theory and argue that this measure, which we call relative configurational entropy (RCE), may be used to quantify the emergence of coherent low-entropy configurations, such as time-dependent or time-independent topological and nontopological spatially-extended structures. As an illustration, we investigate the nonequilibrium dynamics of spontaneous symmetry-breaking in three spatial dimensions. In particular, we focus on a model where a real scalar field, prepared initially in a symmetric thermal state, is quenched to a broken-symmetric state. For a certain range of initial temperatures, spatially-localized, long-lived structures known as oscillons emerge in synchrony and remain until the field reaches equilibrium again. We show that the RCE correlates with the number-density of oscillons, thus offering a quantitative measure of the emergence of nonperturbative spatiotemporal patterns that can be generalized to a variety of physical systems.
Pole Inflation - Shift Symmetry and Universal Corrections
Broy, Benedict J; Roest, Diederik; Westphal, Alexander
2015-01-01
An appealing explanation for the Planck data is provided by inflationary models with a non-canonical kinetic term: a Laurent expansion of the kinetic function translates into a potential with a nearly shift-symmetric plateau in canonical fields. The shift symmetry can be broken at large field values by including higher-order poles. We show that the resulting corrections to the inflationary dynamics and predictions are universal at lowest order, and can induce power loss at large angular scales. At lowest order there are no corrections from a pole of one order higher; this is referred to as extended no-scale in string theory and we explain why this is a general phenomenon. Finally, we outline which other corrections may arise as string loop corrections.
Offline detection of broken rotor bars in AC induction motors
Powers, Craig Stephen
ABSTRACT. OFFLINE DETECTION OF BROKEN ROTOR BARS IN AC INDUCTION MOTORS. The detection of the broken rotor bar defect in medium- and large-sized AC induction machines is currently one of the most difficult tasks for the motor condition and monitoring industry. If a broken rotor bar defect goes undetected, it can cause a catastrophic failure of an expensive machine. If a broken rotor bar defect is falsely determined, it wastes time and money to physically tear down and inspect the machine only to find an incorrect diagnosis. Previous work in 2009 at Baker/SKF-USA in collaboration with the Korea University has developed a prototype instrument that has been highly successful in correctly detecting the broken rotor bar defect in ACIMs where other methods have failed. Dr. Sang Bin and his students at the Korea University have been using this prototype instrument to help the industry save money in the successful detection of the BRB defect. A review of the current state of motor conditioning and monitoring technology for detecting the broken rotor bar defect in ACIMs shows improved detection of this fault is still relevant. An analysis of previous work in the creation of this prototype instrument leads into the refactoring of the software and hardware into something more deployable, cost effective and commercially viable.
Broken Ergodicity in Two-Dimensional Homogeneous Magnetohydrodynamic Turbulence
Shebalin, John V.
2010-01-01
Two-dimensional (2-D) homogeneous magnetohydrodynamic (MHD) turbulence has many of the same qualitative features as three-dimensional (3-D) homogeneous MHD turbulence.The se features include several ideal invariants, along with the phenomenon of broken ergodicity. Broken ergodicity appears when certain modes act like random variables with mean values that are large compared to their standard deviations, indicating a coherent structure or dynamo.Recently, the origin of broken ergodicity in 3-D MHD turbulence that is manifest in the lowest wavenumbers was explained. Here, a detailed description of the origins of broken ergodicity in 2-D MHD turbulence is presented. It will be seen that broken ergodicity in ideal 2-D MHD turbulence can be manifest in the lowest wavenumbers of a finite numerical model for certain initial conditions or in the highest wavenumbers for another set of initial conditions.T he origins of broken ergodicity in ideal 2-D homogeneous MHD turbulence are found through an eigen analysis of the covariance matrices of the modal probability density functions.It will also be shown that when the lowest wavenumber magnetic field becomes quasi-stationary, the higher wavenumber modes can propagate as Alfven waves on these almost static large-scale magnetic structures
Leviatan, A
2010-01-01
This overview focuses on the notion of partial dynamical symmetry (PDS), for which a prescribed symmetry is obeyed by a subset of solvable eigenstates, but is not shared by the Hamiltonian. General algorithms are presented to identify interactions, of a given order, with such intermediate-symmetry structure. Explicit bosonic and fermionic Hamiltonians with PDS are constructed in the framework of models based on spectrum generating algebras. PDSs of various types are shown to be relevant to nuclear spectroscopy, quantum phase transitions and systems with mixed chaotic and regular dynamics.
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.
From enemies to friends chiral symmetry on the lattice
Hernández, Pilar; Lellouch, L P; Hernandez, Pilar; Jansen, Karl; Lellouch, Laurent
2002-01-01
The physics of strong interactions is invariant under the exchange of left-handed and right-handed quarks, at least in the massless limit. This invariance is reflected in the chiral symmetry of quantum chromodynamics. Surprisingly, it has become clear only recently how to implement this important symmetry in lattice formulations of quantum field theories. We will discuss realizations of exact lattice chiral symmetry and give an example of the computation of a physical observable in quantum chromodynamics where chiral symmetry is important. This calculation is performed by relying on finite size scaling methods as predicted by chiral perturbation theory.
On the Membrane Paradigm and Spontaneous Breaking of Horizon BMS Symmetries
Eling, Christopher
2016-01-01
We consider a BMS-type symmetry action on isolated horizons in asymptotically flat spacetimes. From the viewpoint of the non-relativistic field theory on a horizon membrane, supertranslations shift the field theory spatial momentum. The latter is related by a Ward identity to the particle number symmetry current and is spontaneously broken. The corresponding Goldstone boson shifts the horizon angular momentum and can be detected quantum mechanically. Similarly, area preserving superrotations are spontaneously broken on the horizon membrane and we identify the corresponding gapless modes. In asymptotically AdS spacetimes we study the BMS-type symmetry action on the horizon in a holographic superfluid dual. We identify the horizon supertranslation Goldstone boson as the holographic superfluid Goldstone mode.
On the membrane paradigm and spontaneous breaking of horizon BMS symmetries
Eling, Christopher; Oz, Yaron
2016-07-01
We consider a BMS-type symmetry action on isolated horizons in asymptotically flat spacetimes. From the viewpoint of the non-relativistic field theory on a horizon membrane, supertranslations shift the field theory spatial momentum. The latter is related by a Ward identity to the particle number symmetry current and is spontaneously broken. The corresponding Goldstone boson shifts the horizon angular momentum and can be detected quantum mechanically. Similarly, area preserving superrotations are spontaneously broken on the horizon membrane and we identify the corresponding gapless modes. In asymptotically AdS spacetimes we study the BMS-type symmetry action on the horizon in a holographic superfluid dual. We identify the horizon supertranslation Goldstone boson as the holographic superfluid Goldstone mode.
Shear viscosity in holography and effective theory of transport without translational symmetry
Burikham, Piyabut
2016-01-01
We study the shear viscosity in an effective hydrodynamic theory and holographic model where the translational symmetry is broken by massless scalar fields. We identify the shear viscosity, $\\eta$, from the coefficient of the shear tensor in the modified constitutive relation, constructed from thermodynamic quantities, fluid velocity and the scalar fields, which break the translational symmetry explicitly. Our construction of constitutive relation is inspired by those derived from the fluid/gravity correspondence in the weakly disordered limit $m/T \\ll 1$. We found that the shear viscosity - entropy density ratio violate the KSS bound even when the translational symmetry is weakly broken. At the leading order in disorder strength, as the energy density is fixed and the disorder strength increases, we observe that the shear viscosity remains unchanged while the entropy grows larger, resulting in the violation of the bound. At higher order correction in $m/T$, we show that the shear viscosity from the constitut...
Conformal symmetry and its breaking in two dimensional Nearly Anti-de-Sitter space
Maldacena, Juan; Yang, Zhenbin
2016-01-01
We study a two dimensional dilaton gravity system, recently examined by Almheiri and Polchinski, which describes near extremal black holes, or more generally, nearly $AdS_2$ spacetimes. The asymptotic symmetries of $AdS_2$ are all the time reparametrizations of the boundary. These symmetries are spontaneously broken by the $AdS_2$ geometry and they are explicitly broken by the small deformation away from $AdS_2$. This pattern of spontaneous plus explicit symmetry breaking governs the gravitational backreaction of the system. It determines several gravitational properties such as the linear in temperature dependence of the near extremal entropy as well as the gravitational corrections to correlation functions. These corrections include the ones determining the growth of out of time order correlators that is indicative of chaos. These gravitational aspects can be described in terms of a Schwarzian derivative effective action for a reparametrization.
Rychkov, Slava; Vitale, Lorenzo G.
2016-03-01
The Fock-space Hamiltonian truncation method is developed further, paying particular attention to the treatment of the scalar field zero mode. This is applied to the two-dimensional ϕ4 theory in the phase where the Z2 -symmetry is spontaneously broken, complementing our earlier study of the Z2 -invariant phase and of the critical point. We also check numerically the weak/strong duality of this theory discussed long ago by Chang.
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.
Lovelady, Benjamin C
2015-01-01
According to the Coleman-Mandula theorem, any gauge theory of gravity combined with an internal symmetry based on a Lie group must take the form of a direct product in order to be consistent with basic assumptions of quantum field theory. However, we show that an alternative gauging of a simple group can lead dynamically to a spacetime with compact internal symmetry. The biconformal gauging of the conformal symmetry of n-dim Euclidean space doubles the dimension to give a symplectic manifold. Examining one of the Lagrangian submanifolds in the flat case, we find that in addition to the expected SO(n) connection and curvature, the solder form necessarily becomes Lorentzian. General coordinate invariance gives rise to an SO(n-1,1) connection on the spacetime. The principal fiber bundle character of the original SO(n) guarantees that the two symmetries enter as a direct product, in agreement with the Coleman-Mandula theorem.
Gauge symmetry from decoupling
Energy Technology Data Exchange (ETDEWEB)
Wetterich, C., E-mail: c.wetterich@thphys.uni-heidelberg.de
2017-02-15
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.
Gauge symmetry from decoupling
Directory of Open Access Journals (Sweden)
C. Wetterich
2017-02-01
Full Text Available 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.
CPT Symmetry Without Hermiticity
Mannheim, Philip D
2016-01-01
In the literature the $CPT$ theorem has only been established for Hamiltonians that are Hermitian. Here we extend the $CPT$ theorem to quantum field theories with non-Hermitian Hamiltonians. Our derivation is a quite minimal one as it requires only the time independent evolution of scalar products and invariance under complex Lorentz transformations. The first of these requirements does not force the Hamiltonian to be Hermitian. Rather, it forces its eigenvalues to either be real or to appear in complex conjugate pairs, forces the eigenvectors of such conjugate pairs to be conjugates of each other, and forces the Hamiltonian to admit of an antilinear symmetry. The latter requirement then forces this antilinear symmetry to be $CPT$, with Hermiticity of a Hamiltonian thus only being a sufficient condition for $CPT$ symmetry and not a necessary one. $CPT$ symmetry thus has primacy over Hermiticity, and it rather than Hermiticity should be taken as a guiding principle for constructing quantum theories. With confo...
Gauge symmetry from decoupling
Wetterich, C.
2017-02-01
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.
Lovelady, Benjamin C.; Wheeler, James T.
2016-04-01
According to the Coleman-Mandula theorem, any gauge theory of gravity combined with an internal symmetry based on a Lie group must take the form of a direct product in order to be consistent with basic assumptions of quantum field theory. However, we show that an alternative gauging of a simple group can lead dynamically to a spacetime with compact internal symmetry. The biconformal gauging of the conformal symmetry of n-dimensional Euclidean space doubles the dimension to give a symplectic manifold. Examining one of the Lagrangian submanifolds in the flat case, we find that in addition to the expected S O (n ) connection and curvature, the solder form necessarily becomes Lorentzian. General coordinate invariance gives rise to an S O (n -1 ,1 ) connection on the spacetime. The principal fiber bundle character of the original S O (n ) guarantees that the two symmetries enter as a direct product, in agreement with the Coleman-Mandula theorem.
Symmetries, Horizons, and Black Hole Entropy
Carlip, S
2007-01-01
Black holes behave as thermodynamic systems, and a central task of any quantum theory of gravity is to explain these thermal properties. A statistical mechanical description of black hole entropy once seemed remote, but today we suffer an embarrassment of riches: despite counting very different states, many inequivalent approaches to quantum gravity obtain identical results. Such ``universality'' may reflect an underlying two-dimensional conformal symmetry near the horizon, which can be powerful enough to control the thermal characteristics independent of other details of the theory. This picture suggests an elegant description of the relevant degrees of freedom as Goldstone-boson-like excitations arising from symmetry breaking by the conformal anomaly.
Quregisters, Symmetry Groups and Clifford Algebras
Cervantes, D.; Morales-Luna, G.
2016-03-01
Natural one-to-one and two-to-one homomorphisms from SO(3) into SU(2) are built conventionally, and the collection of qubits, is identified with a subgroup of SU(2). This construction is suitable to be extended to corresponding tensor powers. The notions of qubits, quregisters and qugates are translated into the language of symmetry groups. The corresponding elements to entangled states in the tensor product of Hilbert spaces reflect entanglement properties as well, and in this way a notion of entanglement is realised in the tensor product of symmetry groups.
Superconductivity and symmetry breaking
Energy Technology Data Exchange (ETDEWEB)
Sarasua, L.G., E-mail: sarasua@fisica.edu.uy [Instituto de Fisica, Facultad de Ciencias, Universidad de la Republica, Montevideo (Uruguay)
2012-02-15
In the present work we consider the relation between superconductivity and spontaneous gauge symmetry breaking (SGBS). We show that ODLRO does not require in principle SBGS, even in the presence of particle number fluctuations, by examining exact solutions of a fermionic pairing model. The criteria become equivalent if a symmetry breaking field is allowed, which can be attributed to the interaction with the environment. However, superconducting states without SBGS are not forbidden.
Hamhalter, Jan; Turilova, Ekaterina
2017-02-01
Quantum symmetries of spectral lattices are studied. Basic properties of spectral order on A W ∗-algebras are summarized. Connection between projection and spectral automorphisms is clarified by showing that, under mild conditions, any spectral automorphism is a composition of function calculus and Jordan ∗-automorphism. Complete description of quantum spectral symmetries on Type I and Type II A W ∗-factors are completely described.
Baldo, M.; Burgio, G. F.
2016-11-01
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 energy in relation to nuclear structure, astrophysics of Neutron Stars and supernovae, and heavy ion collision experiments, trying to elucidate the connections of these different fields on the basis of the symmetry energy peculiarities. The interplay between experimental and observational data and theoretical developments is stressed. The expected future developments and improvements are schematically addressed, together with most demanded experimental and theoretical advances for the next few years.
Reflections on Conformal Spectra
Kim, Hyungrok; Ooguri, Hirosi
2015-01-01
We use modular invariance and crossing symmetry of conformal field theory to reveal approximate reflection symmetries in the spectral decompositions of the partition function in two dimensions in the limit of large central charge and of the four-point function in any dimension in the limit of large scaling dimensions $\\Delta_0$ of external operators. We use these symmetries to motivate universal upper bounds on the spectrum and the operator product expansion coefficients, which we then derive by independent techniques. Some of the bounds for four-point functions are valid for finite $\\Delta_0$ as well as for large $\\Delta_0$. We discuss a similar symmetry in a large spacetime dimension limit. Finally, we comment on the analogue of the Cardy formula and sparse light spectrum condition for the four-point function.
Reflections on Conformal Spectra
CERN. Geneva
2015-01-01
We use modular invariance and crossing symmetry of conformal field theory to reveal approximate reflection symmetries in the spectral decompositions of the partition function in two dimensions in the limit of large central charge and of the four-point function in any dimension in the limit of large scaling dimensions Δ0 of external operators. We use these symmetries to motivate universal upper bounds on the spectrum and the operator product expansion coefficients, which we then derive by independent techniques. Some of the bounds for four-point functions are valid for finite Δ0 as well as for large Δ0. We discuss a similar symmetry in a large spacetime dimension limit. Finally, we comment on the analogue of the Cardy formula and sparse light spectrum condition for the four-point function. (based on 1510.08772 with Kim & Ooguri). This seminar will be given via videolink
2006-04-01
). Fragment B seems to have fragmented again, bringing the total of fragments close to 40, some being most probably very small, boulder-sized objects with irregular and short-lived activity. The new observations reveal that this new small fragment has split again! The image clearly reveals that below the main B fragment, there is a small fragment that is divided into two and a careful analysis reveals five more tiny fragments almost aligned. Thus, this image alone shows at least 7 fragments. The comet has thus produced a whole set of mini-comets! ESO PR Photo 15b/06 ESO PR Photo 15b/06 Broken Fragments of Comet SW-3 Will the process continue? Will more and more fragments form and will the comet finally disintegrate? How bright will the fragments be when the comet will be the closest to the Earth, on 11 to 14 May, and how many new fragments will have appeared before the comet reaches its closest approach to the Sun, around 7 June? Fragment C of the comet should be the closest to Earth on 11 May, when it will be about 12 million km away, while fragment B will come as 'close' as 10 million km from Earth on 14 May. Although this is the closest a comet ever approached Earth in more than twenty years - even Comet Hyakutake's smallest distance was 15 million km - this is still 26 times the distance between the Earth and the Moon and therefore does not pose any threat to our planet. ESO PR Photo 15/06 ESO PR Photo 15c/06 Mini-Comets coming off Comet SW-3 If nothing else happens, at the time of closest approach, fragment B will be just visible with unaided eye by experienced observers. It should be an easy target however to observe with binoculars. If we are lucky, however, fragment B presents another outburst, becoming a magnificent sight in the night sky. On the other hand, it could just as well fade away into oblivion. But then, the main fragment C should still be visible, even possibly with the unaided eye. ESO telescopes will observe the comet in the greatest detail at the end of
Giant Goos-Hänchen shift using PT symmetry
Ziauddin; Chuang, You-Lin; Lee, Ray-Kuang
2015-07-01
Influence of PT symmetry on the Goos-Hänchen (GH) shift in the reflected light is presented for an ensemble of atomic medium in a cavity, in the configuration of four-level N -type (87Rb atoms) systems driving by two copropagating strong laser fields and a weak probe field. The atom-field interaction follows the realization of PT symmetry by adjusting the coupling field detunings [J. Shenget al., Phys. Rev. A 88, 041803(R) (2013), 10.1103/PhysRevA.88.041803]. A giant enhancement for the GH shift in the reflected light is revealed when the PT -symmetry condition is satisfied.
Low-Scale Leptogenesis and the Domain Wall Problem in Models with Discrete Flavor Symmetries
Riva, Francesco
2010-01-01
We propose a new mechanism for leptogenesis, which is naturally realized in some models with a flavor symmetry based on the discrete group A_4, where the symmetry breaking parameter also controls the Majorana masses for the heavy right handed (RH) neutrinos. During the early universe, for T>TeV, part of the symmetry is restored, due to finite temperature contributions, and the RH neutrinos remain massless and can be produced in thermal equilibrium even at temperatures well below the most conservative gravitino bounds. Below this temperature the phase transition occurs and they become massive, decaying out of equilibrium and producing the necessary lepton asymmetry. Unless the symmetry is broken explicitly by Planck-suppressed terms, the domain walls generated by the symmetry breaking survive till the quark-hadron phase transition, where they disappear due to a small energy splitting between different vacua caused by the QCD anomaly.
Friedberg-Lee symmetry and tribimaximal neutrino mixing in the inverse seesaw mechanism
Chan, Aik Hui; Low, Hwee Boon; Xing, Zhi-Zhong
2009-10-01
The inverse seesaw mechanism with three pairs of gauge-singlet neutrinos offers a natural interpretation of the tiny masses of three active neutrinos at the TeV scale. We combine this picture with the newly proposed Friedberg-Lee (FL) symmetry in order to understand the observed pattern of neutrino mixing. We show that the FL symmetry requires only two pairs of the gauge-singlet neutrinos to be massive, implying that one active neutrino must be massless. We propose a phenomenological ansatz with broken FL symmetry and exact μ-τ symmetry in the gauge-singlet neutrino sector, and obtain the tribimaximal neutrino mixing pattern by means of the inverse seesaw relation. We demonstrate that nonunitary corrections to this result can possibly reach the percent level, and a soft breaking of μ-τ symmetry can give rise to CP violation in such a TeV-scale seesaw scenario.
Universal Symmetry of Complexity and Its Manifestations at Different Levels of World Dynamics
Kirilyuk, A P
2004-01-01
The unreduced, universally nonperturbative analysis of arbitrary interaction process, described by a quite general equation, provides the truly complete, "dynamically multivalued" general solution that leads to dynamically derived, universal definitions of randomness, probability, chaoticity, complexity, fractality, self-organisation, and other properties, extending their axiomatic introduction in the conventional, dynamically single-valued (unitary) theory (physics/9806002, physics/0211071). Any real system emergence, structure, and behaviour can be expressed now by the universal law of conservation, or symmetry, of complexity that unifies extended versions of any (correct) symmetry, law, or "principle". Both the observed world structure and its unreduced dynamics result from that universal, unique symmetry, instead of formal imposition of separated, broken and simplified symmetries upon the existing, postulated structures in the unitary world "model". Whereas any unitary "symmetry" is regular and therefore ...
Friedberg-Lee symmetry and tri-bimaximal neutrino mixing in the inverse seesaw mechanism
Chan, Aik Hui; Xing, Zhi-zhong
2009-01-01
The inverse seesaw mechanism with three pairs of gauge-singlet neutrinos offers a natural interpretation of the tiny masses of three active neutrinos at the TeV scale. We combine this picture with the newly-proposed Friedberg-Lee (FL) symmetry in order to understand the observed pattern of neutrino mixing. We show that the FL symmetry requires only two pairs of the gauge-singlet neutrinos to be massive, implying that one active neutrino must be massless. We propose a phenomenological ansatz with broken FL symmetry and exact \\mu-\\tau symmetry in the gauge-singlet neutrino sector and obtain the tri-bimaximal neutrino mixing pattern by means of the inverse seesaw relation. We demonstrate that non-unitary corrections to this result are possible to reach the percent level and a soft breaking of \\mu-\\tau symmetry can give rise to CP violation in such a TeV-scale seesaw scenario.
Local conformal symmetry in black holes, standard model, and quantum gravity
Hooft, Gerard ’T.
The black hole information problem and the firewall problem can be addressed by assuming an extra local symmetry: conformal invariance. It must be an exact symmetry, spontaneously broken by the vacuum, in a way similar to the Brout-Englert-Higgs (BEH) mechanism. We note how this symmetry formally removes the horizon and the singularity inside black holes. For the Standard Model this symmetry is severely restrictive, demanding all coupling constants, masses and even the cosmological constant to be computable, in principle. Finally, this symmetry suggests that the Weyl action (the square of the Weyl curvature) should be added to the Einstein-Hilbert action. The ensuing indefinite metric states are briefly studied, and we conclude with some remarks concerning the interpretation of quantum mechanics.
Spontaneous symmetry breaking in vortex systems with two repulsive lengthscales
Curran, P. J.; Desoky, W. M.; Milos̆ević, M. V.; Chaves, A.; Laloë, J.-B.; Moodera, J. S.; Bending, S. J.
2015-01-01
Scanning Hall probe microscopy (SHPM) has been used to study vortex structures in thin epitaxial films of the superconductor MgB2. Unusual vortex patterns observed in MgB2 single crystals have previously been attributed to a competition between short-range repulsive and long-range attractive vortex-vortex interactions in this two band superconductor; the type 1.5 superconductivity scenario. Our films have much higher levels of disorder than bulk single crystals and therefore both superconducting condensates are expected to be pushed deep into the type 2 regime with purely repulsive vortex interactions. We observe broken symmetry vortex patterns at low fields in all samples after field-cooling from above Tc. These are consistent with those seen in systems with competing repulsions on disparate length scales, and remarkably similar structures are reproduced in dirty two band Ginzburg-Landau calculations, where the simulation parameters have been defined by experimental observations. This suggests that in our dirty MgB2 films, the symmetry of the vortex structures is broken by the presence of vortex repulsions with two different lengthscales, originating from the two distinct superconducting condensates. This represents an entirely new mechanism for spontaneous symmetry breaking in systems of superconducting vortices, with important implications for pinning phenomena and high current density applications. PMID:26492969
A light sterile neutrino from Friedberg–Lee symmetry
Energy Technology Data Exchange (ETDEWEB)
He, Xiao-Gang [Shanghai Key Laboratory of Particle Physics and Cosmology, Shanghai (China); INPAC and Department of Physics, Shanghai Jiao Tong University, Shanghai (China); Physics Division, National Center for Theoretical Sciences, Department of Physics, National Tsing Hua University, Hsinchu, Taiwan (China); CTS, CASTS and Department of Physics, National Taiwan University, Taipei, Taiwan (China); Liao, Wei, E-mail: liaow@ecust.edu.cn [Institute of Modern Physics, School of Science, East China University of Science and Technology, Shanghai (China)
2014-01-20
Light sterile neutrinos of mass about an eV with mixing U{sup -tilde}{sub ls} of a few percent to active neutrinos may solve some anomalies shown in experimental data related to neutrino oscillation. How to have light sterile neutrinos is one of the theoretical problems which have attracted a lot of attentions. In this article we show that such an eV scale light sterile neutrino candidate can be obtained in a seesaw model in which the right-handed neutrinos satisfy a softly-broken Friedberg–Lee (FL) symmetry. In this model a right-handed neutrino is guaranteed by the FL symmetry to be light comparing with other two heavy right-handed neutrinos. It can be of eV scale when the FL symmetry is softly broken and can play the role of eV scale sterile neutrino needed for explaining the anomalies of experimental data. This model predicts that one of the active neutrino is massless. We find that this model prefers inverted hierarchy mass pattern of active neutrinos than normal hierarchy. An interesting consequence of this model is that realizing relatively large |U{sup -tilde}{sub es}| and relatively small |U{sup -tilde}{sub μs}| in this model naturally leads to a relatively small |U{sup -tilde}{sub τs}|. This interesting prediction can be tested in future atmospheric or solar neutrino experiments.
A light sterile neutrino from Friedberg-Lee symmetry
He, Xiao-Gang; Liao, Wei
2014-01-01
Light sterile neutrinos of mass about an eV with mixing U of a few percent to active neutrinos may solve some anomalies shown in experimental data related to neutrino oscillation. How to have light sterile neutrinos is one of the theoretical problems which have attracted a lot of attentions. In this article we show that such an eV scale light sterile neutrino candidate can be obtained in a seesaw model in which the right-handed neutrinos satisfy a softly-broken Friedberg-Lee (FL) symmetry. In this model a right-handed neutrino is guaranteed by the FL symmetry to be light comparing with other two heavy right-handed neutrinos. It can be of eV scale when the FL symmetry is softly broken and can play the role of eV scale sterile neutrino needed for explaining the anomalies of experimental data. This model predicts that one of the active neutrino is massless. We find that this model prefers inverted hierarchy mass pattern of active neutrinos than normal hierarchy. An interesting consequence of this model is that realizing relatively large |U| and relatively small |U| in this model naturally leads to a relatively small |U|. This interesting prediction can be tested in future atmospheric or solar neutrino experiments.
A Light Sterile Neutrino from Friedberg-Lee Symmetry
He, Xiao-Gang
2013-01-01
Light sterile neutrinos of mass about an eV with mixing $\\tilde U_{ls}$ of a few percent to active neutrinos may solve some anomalies shown in experimental data related to neutrino oscillation. How to have light sterile neutrinos is one of the theoretical problems which have attracted a lot of attentions. In this article we show that such an eV scale light sterile neutrino candidate can be obtained in a seesaw model in which the right-handed neutrinos satisfy a softly-broken Friedberg-Lee (FL) symmetry. In this model a right-handed neutrino is guaranteed by the FL symmetry to be light comparing with other two heavy right-handed neutrinos. It can be of eV scale when the FL symmetry is softly broken and can play the role of eV scale sterile neutrino needed for explaining the anomalies of experimental data. This model predicts that one of the active neutrino is massless. We find that this model prefers inverted hierarchy mass pattern of active neutrinos than normal hierarchy. An interesting consequence of this m...
Kawamura, Yoshiharu
2015-01-01
We study the quantization of systems with local particle-ghost symmetries. The systems contain ordinary particles including gauge bosons and their counterparts obeying different statistics. The particle-ghost symmetry is a kind of fermionic symmetry, different from the space-time supersymmetry and the BRST symmetry. Subsidiary conditions on states guarantee the unitarity of systems.
Broken-Rotor-Bar Diagnosis for Induction Motors
Wang, Jinjiang; Gao, Robert X.; Yan, Ruqiang
2011-07-01
Broken rotor bar is one of the commonly encountered induction motor faults that may cause serious motor damage to the motor if not detected timely. Past efforts on broken rotor bar diagnosis have been focused on current signature analysis using spectral analysis and wavelet transform. These methods require accurate slip estimation to localize fault-related frequency. This paper presents a new approach to broken rotor bar diagnosis without slip estimation, based on the ensemble empirical mode decomposition (EEMD) and the Hilbert transform. Specifically, the Hilbert transform first extracts the envelope of the motor current signal, which contains broken rotor fault-related frequency information. Subsequently, the envelope signal is adaptively decomposed into a number of intrinsic mode functions (IMFs) by the EEMD algorithm. Two criteria based on the energy and correlation analyses have been investigated to automate the IMF selection. Numerical and experimental studies have confirmed that the proposed approach is effective in diagnosing broken rotor bar faults for improved induction motor condition monitoring and damage assessment.
Bifurcation and catastrophe of seepage flow system in broken rock
Institute of Scientific and Technical Information of China (English)
MIAO Xie-xing; LI Shun-cai; CHEN Zhan-qing
2009-01-01
The study of dynamical behavior of water or gas flows in broken rock is a basic research topic among a series of key projects about stability control of the surrounding rocks in mines and the prevention of some disasters such as water inrush or gas outburst and the protection of the groundwater resource. It is of great theoretical and engineering importance in respect of promo-tion of security in mine production and sustainable development of the coal industry. According to the non-Darcy property of seepage flow in broken rock dynamic equations of non-Darcy and non-steady flows in broken rock are established. By dimensionless transformation, the solution diagram of steady-states satisfying the given boundary conditions is obtained. By numerical analysis of low relaxation iteration, the dynamic responses corresponding to the different flow parameters have been obtained. The stability analysis of the steady-states indicate that a saddle-node bifurcaton exists in the seepage flow system of broken rock. Consequently, using catastrophe theory, the fold catastrophe model of seepage flow instability has been obtained. As a result, the bifurcation curves of the seepage flow systems with different control parameters are presented and the standard potential function is also given with respect to the generalized state variable for the fold catastrophe of a dynamic system of seepage flow in broken rock.
Symmetry-breaking oscillations in membrane optomechanics
Wurl, C.; Alvermann, A.; Fehske, H.
2016-12-01
We study the classical dynamics of a membrane inside a cavity in the situation where this optomechanical system possesses a reflection symmetry. Symmetry breaking occurs through supercritical and subcritical pitchfork bifurcations of the static fixed-point solutions. Both bifurcations can be observed through variation of the laser-cavity detuning, which gives rise to a boomerang-like fixed-point pattern with hysteresis. The symmetry-breaking fixed points evolve into self-sustained oscillations when the laser intensity is increased. In addition to the analysis of the accompanying Hopf bifurcations we describe these oscillations at finite amplitudes with an ansatz that fully accounts for the frequency shift relative to the natural membrane frequency. We complete our study by following the route to chaos for the membrane dynamics.
Repairing the broken market for antibiotic innovation.
Outterson, Kevin; Powers, John H; Daniel, Gregory W; McClellan, Mark B
2015-02-01
Multidrug-resistant bacterial diseases pose serious and growing threats to human health. While innovation is important to all areas of health research, it is uniquely important in antibiotics. Resistance destroys the fruit of prior research, making it necessary to constantly innovate to avoid falling back into a pre-antibiotic era. But investment is declining in antibiotics, driven by competition from older antibiotics, the cost and uncertainty of the development process, and limited reimbursement incentives. Good public health practices curb inappropriate antibiotic use, making return on investment challenging in payment systems based on sales volume. We assess the impact of recent initiatives to improve antibiotic innovation, reflecting experience with all sixty-seven new molecular entity antibiotics approved by the Food and Drug Administration since 1980. Our analysis incorporates data and insights derived from several multistakeholder initiatives under way involving governments and the private sector on both sides of the Atlantic. We propose three specific reforms that could revitalize innovations that protect public health, while promoting long-term sustainability: increased incentives for antibiotic research and development, surveillance, and stewardship; greater targeting of incentives to high-priority public health needs, including reimbursement that is delinked from volume of drug use; and enhanced global collaboration, including a global treaty.
Neutrino Mass and Mixing with Discrete Symmetry
King, Stephen F
2013-01-01
This is a review article about neutrino mass and mixing and flavour model building strategies based on discrete family symmetry. After a pedagogical introduction and overview of the whole of neutrino physics, we focus on the PMNS mixing matrix and the latest global fits following the Daya Bay and RENO experiments which measure the reactor angle. We then describe the simple bimaximal, tri-bimaximal and golden ratio patterns of lepton mixing and the deviations required for a non-zero reactor angle, with solar or atmospheric mixing sum rules resulting from charged lepton corrections or residual trimaximal mixing. The different types of seesaw mechanism are then reviewed as well as the sequential dominance mechanism. We then give a mini-review of finite group theory, which may be used as a discrete family symmetry broken by flavons either completely, or with different subgroups preserved in the neutrino and charged lepton sectors. These two approaches are then reviewed in detail in separate chapters including mec...
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.
Energy Technology Data Exchange (ETDEWEB)
Joshipura, A.S. [Physical Research Laboratory, Navarangpura, Ahmedabad (India)
2008-01-15
The possible maximal mixing seen in the oscillations of atmospheric neutrinos has led to the postulate of {mu}-{tau} symmetry, which interchanges {nu}{sub {mu}} and {nu}{sub {tau}}. We argue that such a symmetry need not be special to neutrinos but can be extended to all fermions. The assumption that all fermion mass matrices are approximately invariant under the interchange of the second and the third generation fields is shown to be phenomenologically viable and has interesting consequences. In the quark sector, the smallness of V{sub ub} and V{sub cb} can be consequences of this approximate 2-3 symmetry. The same approximate symmetry can simultaneously lead to a large atmospheric mixing angle and can describe the leptonic mixing quite well. We identify two generic scenarios leading to this. One is based on the conventional type-I seesaw mechanism and the other follows from the type-II seesaw model. The latter requires a quasi-degenerate neutrino spectrum for obtaining large atmospheric neutrino mixing in the presence of an approximate {mu}-{tau} symmetry. (orig.)
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.
Experimental Study on the Porosity Creep Properties of Broken Limestone
Directory of Open Access Journals (Sweden)
Li Shun-cai
2016-01-01
Full Text Available In the underground engineering, the long-term stability of the surrounding rocks (especially the broken rocks containing water and the ground settlement resulted from the seepage-creep coupling above goaf have been the important research subjects concerning the deep mining. For the broken rock, its porosity is an important structural parameter determining its creep properties, and the porosity change rate is more superior to describe the creep characteristics compared with the strain change rate at a certain direction. In this paper, MTS815.02 Rock Mechanics Test System is used to carry out the creep experiments on water-saturated broken limestone, and then the time curves of porosity and of the porosity change rate are obtained. By regression, we have got the relation equation between the porosity change rate with the instant porosity and the stress level during the creep. The study indicates that when the stress retains a constant level, the relation between the porosity change rate and the instant porosity can be fitted with a cubical polynomial. The obtained creep relation equation between the porosity change rate and the instant porosity and the instant stress provides a necessary state equation for studying the coupling between the seepage and the creep of the broken rock. Furthermore, the seepage in the broken rock has been verified to satisfy the Forchheimer’s non-Darcy flow according to our previous studies, and its seepage properties, k, β and ca can all be expressed respectively as the polynomial of the porosity, so, by combining with these three state equations we have obtained the four essential state equations for solving the coupling problems of the seepage and the creep for the broken rocks.
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...
Seeing Science through Symmetry
Gould, L. I.
Seeing Through Symmetry is a course that introduces non-science majors to the pervasive influence of symmetry in science. The concept of symmetry is usedboth as a link between subjects (such as physics, biology, mathematics, music, poetry, and art) and as a method within a subject. This is done through the development and use of interactive multimedia learning environments to stimulate learning. Computer-based labs enable the student to further explore the concept by being gently led from the arts to science. This talk is an update that includes some of the latest changes to the course. Explanations are given on methodology and how a variety of interactive multimedia tools contribute to both the lecture and lab portion of the course (created in 1991 and taught almost every semester since then, including one in Sweden).
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...
Segmentation Using Symmetry Deviation
DEFF Research Database (Denmark)
Hollensen, Christian; Højgaard, L.; Specht, L.
2011-01-01
and evaluate the method. The method uses deformable registration on computed tomography(CT) to find anatomical symmetry deviations of Head & Neck squamous cell carcinoma and combining it with positron emission tomography (PET) images. The method allows the use anatomical and symmetrical information of CT scans...... to improve automatic delineations. Materials: PET/CT scans from 30 patients were used for this study, 20 without cancer in hypopharyngeal volume and 10 with hypharyngeal carcinoma. An head and neck atlas was created from the 20 normal patients. The atlas was created using affine and non-rigid registration...... of the CT-scans into a single atlas. Afterwards the standard deviation of anatomical symmetry for the 20 normal patients was evaluated using non-rigid registration and registered onto the atlas to create an atlas for normal anatomical symmetry deviation. The same non-rigid registration was used on the 10...
Leadership, power and symmetry
DEFF Research Database (Denmark)
Spaten, Ole Michael
2016-01-01
Research publications concerning managers who coach their own employees are barely visible despite its wide- spread use in enterprises (McCarthy & Milner, 2013; Gregory & Levy, 2011; Crabb, 2011). This article focuses on leadership, power and moments of symmetry in the coaching relationship...... session. Thereafter we executed qualitative interviews with both managers and employees. Subsequently, a Thematic Analysis resulted in several themes, including power and moments of symmetry in the coaching relationship. One main conclusion is that the most fruitful coaching was obtained when the coachee...... experienced moments of symmetry and that necessary and sufficient conditions to bring forth such moments include a strong working alliance and the coach being aware of the power at play....
Energy Technology Data Exchange (ETDEWEB)
Chanowitz, M.S.
1990-09-01
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.
Trautmann, Wolfgang; Russotto, Paolo
2016-01-01
The nuclear equation-of-state is a topic of highest current interest in nuclear structure and reactions as well as in astrophysics. In particular, the equation-of-state of asymmetric matter and the symmetry energy representing the difference between the energy densities of neutron matter and of symmetric nuclear matter are not sufficiently well constrained at present. The density dependence of the symmetry energy is conventionally expressed in the form of the slope parameter L describing the derivative with respect to density of the symmetry energy at saturation. Results deduced from nuclear structure and heavy-ion reaction data are distributed around a mean value L=60 MeV. Recent studies have more thoroughly investigated the density range that a particular observable is predominantly sensitive to. Two thirds of the saturation density is a value typical for the information contained in nuclear-structure data. Higher values exceeding saturation have been shown to be probed with meson production and collective ...
Gravitation and Duality Symmetry
D'Andrade, V C; Pereira, J G
2005-01-01
By generalizing the Hodge dual operator to the case of soldered bundles, and working in the context of the teleparallel equivalent of general relativity, an analysis of the duality symmetry in gravitation is performed. Although the basic conclusion is that, at least in the general case, gravitation does not present duality symmetry, there is a particular theory in which this symmetry is present. This theory is a self dual (or anti-self dual) teleparallel gravity in which, owing to the fact that it does not contribute to the gravitational interaction of fermions, the purely tensor part of torsion is assumed to vanish. The corresponding fermionic gravitational interaction is found to be chiral. Since duality is intimately related to renormalizability, this theory will probably be much more amenable to renormalization than teleparallel gravity or general relativity. Although obtained in the context of teleparallel gravity, these results must also be true for general relativity.
Unified flavor symmetry from warped dimensions
Directory of Open Access Journals (Sweden)
Mariana Frank
2015-03-01
Full Text Available In a model of warped extra-dimensions with all matter fields in the bulk, we propose a scenario which explains all the masses and mixings of the SM fermions. In this scenario, the same flavor symmetric structure is imposed on all the fermions of the Standard Model (SM, including neutrinos. Due to the exponential sensitivity on bulk fermion masses, a small breaking of this symmetry can be greatly enhanced and produce seemingly un-symmetric hierarchical masses and small mixing angles among the charged fermion zero-modes (SM quarks and charged leptons, thus washing out visible effects of the symmetry. If the Dirac neutrinos are sufficiently localized towards the UV boundary, and the Higgs field leaking into the bulk, the neutrino mass hierarchy and flavor structure will still be largely dominated and reflect the fundamental flavor structure, whereas localization of the quark sector would reflect the effects of the flavor symmetry breaking sector. We explore these features in an example based on which a family permutation symmetry is imposed in both quark and lepton sectors.
Floquet topological phases protected by time glide symmetry
Morimoto, Takahiro; Po, Hoi Chun; Vishwanath, Ashvin
2017-05-01
We study Floquet topological phases in periodically driven systems that are protected by "time glide symmetry", a combination of reflection and half time period translation. Time glide symmetry is an analog of glide symmetry with partial time translation replacing the partial space translation and, hence, is an intrinsically dynamical symmetry which may be engineered in periodically driven systems by exploiting the controllability of driving. We present lattice models of time glide symmetric Floquet topological insulators in two and three dimensions. The topological numbers characterizing those Floquet topological phases are derived from the half-period time-evolution operator along with time glide operator. Moreover, we classify Floquet topological phases protected by time glide symmetry in general dimensions using a Clifford algebra approach. The obtained classification table is similar to that for topological crystalline insulators protected by static reflection symmetry, but shows nontrivial entries in different combination of symmetries, which clarifies that time glide symmetric Floquet topological phases are a distinct set of topological phases from topological crystalline insulators. We also classify Floquet topological phases with "time screw symmetry", defined as a twofold spatial rotation accompanied by half-period time translation.
Polarity Formation in Molecular Crystals as a Symmetry Breaking Effect
Directory of Open Access Journals (Sweden)
Luigi Cannavacciuolo
2016-03-01
Full Text Available The transition of molecular crystals into a polar state is modeled by a one-dimensional Ising Hamiltonian in multipole expansion and a suitable order parameter. Two symmetry breakings are necessary for the transition: the translational and the spin flip invariance—the former being broken by geometric constraints, the latter by the interaction of the first non-zero multipole with the next order multipole. Two different behaviors of the thermal average of the order parameter as a function of position are found. The free energy per lattice site converges to a finite value in the thermodynamic limit showing the consistency of the model in a macroscopic representation.
Random symmetry breaking and freezing in chaotic networks.
Peleg, Y; Kinzel, W; Kanter, I
2012-09-01
Parameter space of a driven damped oscillator in a double well potential presents either a chaotic trajectory with sign oscillating amplitude or a nonchaotic trajectory with a fixed sign amplitude. A network of such delay coupled damped oscillators is shown to present chaotic dynamics while the sign amplitude of each damped oscillator is randomly frozen. This phenomenon of random broken global symmetry of the network simultaneous with random freezing of each degree of freedom is accompanied by the existence of exponentially many randomly frozen chaotic attractors with the size of the network. Results are exemplified by a network of modified Duffing oscillators with infinite range pseudoinverse delayed interactions.
Configurons: Thermodynamic Parameters and Symmetry Changes at Glass Transition
Directory of Open Access Journals (Sweden)
Michael I. Ojovan
2008-09-01
Full Text Available Thermodynamic parameters of configurons Ã¢Â€Â“ elementary excitations resulting from broken bonds in amorphous materials Ã¢Â€Â“ are found from viscosity-temperature relationships. Glass-liquid transition phenomena and most popular models are described along with the configuron model of glass transition. The symmetry breaking, which occurs as a change of Hausdorff dimension of bonds, is examined at glass-liquid transition. Thermal history effects in the glass-liquid transition are interpreted in terms of configuron relaxation.
Chiral Symmetry in Light-Cone Field Theory
Lenz, F; Thies, M; Yazaki, K
2004-01-01
An analysis of spontaneously broken chiral symmetry in light-cone field theory is presented. The non-locality inherent to light-cone field theory requires revision of the standard procedure in the derivation of Ward-Takahashi identities. We derive the general structure of chiral Ward-Takahashi identities and construct them explicitly for various model field theories. Gell-Mann-Oakes-Renner relations and relations between fermion propagators and the structure functions of Nambu-Goldstone bosons are discussed and the necessary modifications of the Ward-Takahashi identities due to the axial anomaly are indicated.
Flavour from accidental symmetries
Energy Technology Data Exchange (ETDEWEB)
Ferretti, Luca [SISSA/ISAS and INFN, I-34013 Trieste (Italy); King, Stephen F. [School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Romanino, Andrea [SISSA/ISAS and INFN, I-34013 Trieste (Italy)
2006-11-15
We consider a new approach to fermion masses and mixings in which no special 'horizontal' dynamics is invoked to account for the hierarchical pattern of charged fermion masses and for the peculiar features of neutrino masses. The hierarchy follows from the vertical, family-independent structure of the model, in particular from the breaking pattern of the Pati-Salam group. The lightness of the first two fermion families can be related to two family symmetries emerging in this context as accidental symmetries.
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
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.
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.
Wang, Zhijian; Xu, Bin; Zhejiang Collaboration
2011-03-01
In social science, laboratory experiment with human subjects' interaction is a standard test-bed for studying social processes in micro level. Usually, as in physics, the processes near equilibrium are suggested as stochastic processes with time-reversal symmetry (TRS). To the best of our knowledge, near equilibrium, the breaking time symmetry, as well as the existence of robust time anti-symmetry processes, has not been reported clearly in experimental economics till now. By employing Markov transition method to analysis the data from human subject 2x2 Games with wide parameters and mixed Nash equilibrium, we study the time symmetry of the social interaction process near Nash equilibrium. We find that, the time symmetry is broken, and there exists a robust time anti-symmetry processes. We also report the weight of the time anti-symmetry processes in the total processes of each the games. Evidences in laboratory marketing experiments, at the same time, are provided as one-dimension cases. In these cases, time anti-symmetry cycles can also be captured. The proposition of time anti-symmetry processes is small, but the cycles are distinguishable.
Liu, Jian; Kriegner, D.; Horak, L.; Puggioni, D.; Rayan Serrao, C.; Chen, R.; Yi, D.; Frontera, C.; Holy, V.; Vishwanath, A.; Rondinelli, J. M.; Marti, X.; Ramesh, R.
2016-02-01
By using a combination of heteroepitaxial growth, structure refinement based on synchrotron x-ray diffraction, and first-principles calculations, we show that the symmetry-protected Dirac line nodes in the topological semimetallic perovskite SrIrO3 can be lifted simply by applying epitaxial constraints. In particular, the Dirac gap opens without breaking the P b n m mirror symmetry. In virtue of a symmetry-breaking analysis, we demonstrate that the original symmetry protection is related to the n -glide operation, which can be selectively broken by different heteroepitaxial structures. This symmetry protection renders the nodal line a nonsymmorphic Dirac semimetallic state. The results highlight the vital role of crystal symmetry in spin-orbit-coupled correlated oxides and provide a foundation for experimental realization of topological insulators in iridate-based heterostructures.
Broken scale invariance, α -attractors and vector impurity
Akarsu, Özgür; Boran, Sibel; Kahya, Emre Onur; Özdemir, Neşe; Ozkan, Mehmet
2017-05-01
We show that if the α -attractor model is realized by the spontaneous breaking of the scale symmetry, then the stability and the dynamics of the vector field that gauges the scale symmetry can severely constrain the α -parameter as 5/6universe.
Discrete Symmetries of Off-Shell Electromagnetism
Land, M
2005-01-01
We discuss the discrete symmetries of the Stueckelberg-Schrodinger relativistic quantum theory and its associated 5D local gauge theory, a dynamical description of particle/antiparticle interactions, with monotonically increasing Poincare-invariant parameter. In this framework, worldlines are traced out through the parameterized evolution of spacetime events, advancing or retreating with respect to the laboratory clock, with negative energy trajectories appearing as antiparticles when the observer describes the evolution using the laboratory clock. The associated gauge theory describes local interactions between events (correlated by the invariant parameter) mediated by five off-shell gauge fields. These gauge fields are shown to transform tensorially under under space and time reflections, unlike the standard Maxwell fields, and the interacting quantum theory therefore remains manifestly Lorentz covariant. Charge conjugation symmetry in the quantum theory is achieved by simultaneous reflection of the sense o...
Conformal symmetry vs. chiral symmetry breaking in the SU(3) sextet model
Drach, Vincent; Hietanen, Ari; Pica, Claudio; Sannino, Francesco
2015-01-01
We present new results for the SU(3) "sextet model" with two flavors transforming according to the two-index symmetric representation of the gauge group. The simulations are performed using unimproved Wilson fermions. We measure the meson and baryon spectrum of the theory for multiple bare quark masses at two different lattice spacings. To address the pressing issue of whether the model is inside or below the conformal window, we compare the spectrum to the expectations for a theory with spontaneous chiral symmetry breaking and to those of an IR conformal theory. Regardless of the answer (conformal or chirally broken), the theory is a cornerstone in our understanding of near-conformal and composite dynamics, ranging from Technicolor models to unparticle physics. It is also interesting for the composite dynamics of vector-like singlets with respect to the Standard Model interactions.
Extra gauge symmetries in BHT gravity
Blagojević, M
2011-01-01
We study the canonical structure of the Bergshoeff-Hohm-Townsend massive gravity, linearized around a maximally symmetric background. At the critical point in the space of parameters, defined by $\\Lambda_0/m^2=-1$, we discover an extra gauge symmetry, which reflects the existence of the partially massless mode. The number of the Lagrangian degrees of freedom is found to be 1. We show that the canonical structure of the theory at the critical point is unstable under linearization.
Extra gauge symmetries in BHT gravity
Blagojević, M.; Cvetković, B.
2011-03-01
We study the canonical structure of the Bergshoeff-Hohm-Townsend massive gravity, linearized around a maximally symmetric background. At the critical point in the space of parameters, defined by Λ 0/ m 2 = -1, we discover an extra gauge symmetry, which reflects the existence of the partially massless mode. The number of the Lagrangian degrees of freedom is found to be 1. We show that the canonical structure of the theory at the critical point is unstable under linearization.
Dieperink, AEL; van Neck, D; Suzuki, T; Otsuka, T; Ichimura, M
2005-01-01
The role of isospin asymmetry in nuclei and neutron stars is discussed, with an emphasis on the density dependence of the nuclear symmetry energy. Results obtained with the self-consistent Green function method are presented and compared with various other theoretical predictions. Implications for t
Quantum entanglement and symmetry
Energy Technology Data Exchange (ETDEWEB)
Chruscinski, D; Kossakowski, A [Institute of Physics, Nicolaus Copernicus University, Grudziadzka 5/7, 87-100 Torun (Poland)
2007-11-15
One of the main problem in Quantum Information Theory is to test whether a given state of a composite quantum system is entangled or separable. It turns out that within a class of states invariant under the action of the symmetry group this problem considerably simplifies. We analyze multipartite invariant states and the corresponding symmetric quantum channels.
Quantum entanglement and symmetry
Chruściński, D.; Kossakowski, A.
2007-11-01
One of the main problem in Quantum Information Theory is to test whether a given state of a composite quantum system is entangled or separable. It turns out that within a class of states invariant under the action of the symmetry group this problem considerably simplifies. We analyze multipartite invariant states and the corresponding symmetric quantum channels.
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...
Crumpecker, Cheryl
2003-01-01
Describes an art lesson used with children in the third grade to help them learn about symmetry, as well as encouraging them to draw larger than usual. Explains that students learn about the belief called "Horror Vacui" of the Northwest American Indian tribes and create their interpretation of this belief. (CMK)
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...
Pels, D.L.
1996-01-01
While symmetry and impartiality have become ruling principles in S&TS, defining its core ideal of a 'value-free relativism', their philosophical anchorage has attracted much less discussion than the issue or:how far their jurisdiction can be extended or generalized. This paper seeks to argue that sy
Applications of chiral symmetry
Pisarski, R D
1995-01-01
I discuss several topics in the applications of chiral symmetry at nonzero temperature, including: where the rho goes, disoriented chiral condensates, and the phase diagram for QCD with 2+1 flavors. (Based upon talks presented at the "Workshop on Finite Temperature QCD", Wuhan, P.R.C., April, 1994.)
Einmahl, John; Gan, Zhuojiong
2016-01-01
Omnibus tests for central symmetry of a bivariate probability distribution are proposed. The test statistics compare empirical measures of opposite regions. Under rather weak conditions, we establish the asymptotic distribution of the test statistics under the null hypothesis; it follows that they a
Dynamically broken Anti-de Sitter action for gravity
Tresguerres, Romualdo
2008-01-01
Due to a suitable Higgs mechanism, a standard Anti-de Sitter gauge theory becomes spontaneously broken. The resulting Lorentz invariant gravitational action includes the Hilbert-Einstein term of ordinary Einstein-Cartan gravity with cosmological constant, plus contributions quadratic in curvature and torsion, and a scalar Higgs sector.