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.
A broken symmetry ontology: Quantum mechanics as a broken symmetry
International Nuclear Information System (INIS)
Buschmann, J.E.
1988-01-01
The author proposes a new broken symmetry ontology to be used to analyze the quantum domain. This ontology is motivated and grounded in a critical epistemological analysis, and an analysis of the basic role of symmetry in physics. Concurrently, he is led to consider nonheterogeneous systems, whose logical state space contains equivalence relations not associated with the causal relation. This allows him to find a generalized principle of symmetry and a generalized symmetry-conservation formalisms. In particular, he clarifies the role of Noether's theorem in field theory. He shows how a broken symmetry ontology already operates in a description of the weak interactions. Finally, by showing how a broken symmetry ontology operates in the quantum domain, he accounts for the interpretational problem and the essential incompleteness of quantum mechanics. He proposes that the broken symmetry underlying this ontological domain is broken dilation invariance
Broken color symmetry and weak currents
International Nuclear Information System (INIS)
Stech, B.
1976-01-01
Broken colour symmetry predicts a very rich spectrum of new particles. If broken colour is relevant at all, charged psi-particles should be found in particular at the 4 GeV region. For the weak hadronic currents no completely satisfactory suggestion exists. Broken colour symmetry describes qualitatively several of the new effects observed recently. (BJ) [de
Broken SU(4) symmetry and new resonance
International Nuclear Information System (INIS)
Ueda, Y.
1975-11-01
Weinberg's spectral function sum rules are modified to accommodate broken symmetry effects of SU(4). With a simple choice of the symmetry-breaking term, the spectral function sum rules yield the observed vector meson mass spectrum as well as sum rules for the e - e + decay rates of vector mesons. In particular, a new mass formula, which can be interpreted as the broken symmetry version of the Schwinger formula, is derived, the agreement with experiments is excellent. (Ueda, Y.)
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...
Bag model with broken chiral symmetry
International Nuclear Information System (INIS)
Efrosinin, V.P.; Zaikin, D.A.
1986-01-01
A variant of the bag model in which chiral symmetry is broken and which provides a description of all the experimental data on the light hadrons, including the pion, is discussed. The pion and kaon decay constants are calculated in this model. The problem of taking into account the center-of-mass motion in bag models and the boundary conditions in the bag model with broken chiral symmetry are also discussed
Spontaneously broken global symmetries and cosmology
International Nuclear Information System (INIS)
Shafi, Q.; Vilenkin, A.
1984-01-01
Phase transitions associated with spontaneously broken global symmetries, in case these occur in nature, can have important cosmological implications. This is illustrated through two examples. The first one shows how the spontaneous breaking of a global U(1) symmetry, present, for instance, in the minimal SU(5) model, can lead to an inflationary phase. The second example illustrates how topologically stable strings associated with the breaking of U(1) symmetry make an appearance at (or near) the end of the inflationary era
Neutrino masses and spontaneously broken flavor symmetries
International Nuclear Information System (INIS)
Staudt, Christian
2014-01-01
We study the phenomenology of supersymmetric flavor models. We show how the predictions of models based on spontaneously broken non-Abelian discrete flavor symmetries are altered when we include so-called Kaehler corrections. Furthermore, we discuss anomaly-free discrete R symmetries which are compatible with SU(5) unification. We find a set of symmetries compatible with suppressed Dirac neutrino masses and a unique symmetry consistent with the Weinberg operator. We also study a pseudo-anomalous U(1) R symmetry which explains the fermion mass hierarchies and, when amended with additional singlet fields, ameliorates the fine-tuning problem.
International Nuclear Information System (INIS)
Kastner, Ruth E.
2011-01-01
This paper seeks to clarify features of time asymmetry in terms of symmetry breaking. It is observed that, in general, a contingent situation or event requires the breaking of an underlying symmetry. The distinction between the universal anisotropy of temporal processes and the irreversibility of certain physical processes is clarified. It is also proposed that the Transactional Interpretation of quantum mechanics offers an effective way to explain general thermodynamic asymmetry in terms of the time asymmetry of radiation, where prior such efforts have fallen short.
Kastner, Ruth E.
2011-11-01
This paper seeks to clarify features of time asymmetry in terms of symmetry breaking. It is observed that, in general, a contingent situation or event requires the breaking of an underlying symmetry. The distinction between the universal anisotropy of temporal processes and the irreversibility of certain physical processes is clarified. It is also proposed that the Transactional Interpretation of quantum mechanics offers an effective way to explain general thermodynamic asymmetry in terms of the time asymmetry of radiation, where prior such efforts have fallen short.
Renormalizable models with broken symmetries
International Nuclear Information System (INIS)
Becchi, C.; Rouet, A.; Stora, R.
1975-10-01
The results of the renormalized perturbation theory, in the absence of massless quanta, are summarized. The global symmetry breaking is studied and the associated currents are discussed in terms of the coupling with a classical Yang Mills field. Gauge theories are discussed; it is most likely that the natural set up should be the theory of fiber bundles and that making a choice of field coordinates makes the situation obscure. An attempt is made in view of clarifying the meaning of the Slavnov symmetry which characterizes gauge field theories [fr
Soft Terms from Broken Symmetries
Buican, Matthew
2010-01-01
In theories of phyiscs beyond the Standard Model (SM), visible sector fields often carry quantum numbers under additional gauge symmetries. One could then imagine a scenario in which these extra gauge symmetries play a role in transmitting supersymmetry breaking from a hidden sector to the Supersymmetric Standard Model (SSM). In this paper we present a general formalism for studying the resulting hidden sectors and calculating the corresponding gauge mediated soft parameters. We find that a large class of generic models features a leading universal contribution to the soft scalar masses that only depends on the scale of Higgsing, even if the model is strongly coupled. As a by-product of our analysis, we elucidate some IR aspects of the correlation functions in General Gauge Mediation. We also discuss possible phenomenological applications.
N=1 superstrings with spontaneously broken symmetries
International Nuclear Information System (INIS)
Ferrara, S.
1988-01-01
We construct N=1 chiral superstrings with spontaneously broken gauge symmetry in four space-time dimensions. These new string solutions are obtained by a generalized coordinate-dependent Z 2 orbifold compactification of some non-chiral five-dimensional N=1 and N=2 superstrings. The scale of symmetry breaking is arbitrary (at least classically) and it can be chosen hierarchically smaller than the string scale (α') -1/2 . (orig.)
Broken colour symmetry and liberated quarks
International Nuclear Information System (INIS)
Ma, E.
1976-01-01
A quark model of hadrons is presented and discussed, in which local SU(3) gauge symmetry is completely broken and yet asymptotic freedom is preserved. There is no infrared slavery in this model, and isolated quarks are free to exist. Colour becomes a global symmetry which is only approximate under SU(3) but nearly exact under SU(2) x U(1), as far as the usual hadron spectroscopy is concerned. (Auth.)
Quantum Space-Time Deformed Symmetries Versus Broken Symmetries
Amelino-Camelia, G
2002-01-01
Several recent studies have concerned the faith of classical symmetries in quantum space-time. In particular, it appears likely that quantum (discretized, noncommutative,...) versions of Minkowski space-time would not enjoy the classical Lorentz symmetries. I compare two interesting cases: the case in which the classical symmetries are "broken", i.e. at the quantum level some classical symmetries are lost, and the case in which the classical symmetries are "deformed", i.e. the quantum space-time has as many symmetries as its classical counterpart but the nature of these symmetries is affected by the space-time quantization procedure. While some general features, such as the emergence of deformed dispersion relations, characterize both the symmetry-breaking case and the symmetry-deformation case, the two scenarios are also characterized by sharp differences, even concerning the nature of the new effects predicted. I illustrate this point within an illustrative calculation concerning the role of space-time symm...
Holography with broken Poincaré symmetry
Korovins, J.
2014-01-01
This thesis deals with the extensions of the holographic dualities to the situations where part of the Poincaré group has been broken. Such theories are particularly relevant for applications of gauge/gravity dualities to condensed matter systems, which usually exhibit non-relativistic symmetry.
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...... is in accordance with given theoretical arguments. Despite the setup being three dimensional, the ratchet rotary motion is proved to be described by one simple dynamic equation. This kind of motion is a result of the interplay of friction and inertia....
Random-phase approximation and broken symmetry
International Nuclear Information System (INIS)
Davis, E.D.; Heiss, W.D.
1986-01-01
The validity of the random-phase approximation (RPA) in broken-symmetry bases is tested in an appropriate many-body system for which exact solutions are available. Initially the regions of stability of the self-consistent quasiparticle bases in this system are established and depicted in a 'phase' diagram. It is found that only stable bases can be used in an RPA calculation. This is particularly true for those RPA modes which are not associated with the onset of instability of the basis; it is seen that these modes do not describe any excited state when the basis is unstable, although from a formal point of view they remain acceptable. The RPA does well in a stable broken-symmetry basis provided one is not too close to a point where a phase transition occurs. This is true for both energies and matrix elements. (author)
Quantum restoration of broken symmetry in onedimensional loop ...
Indian Academy of Sciences (India)
Home; Journals; Pramana – Journal of Physics; Volume 82; Issue 6. Quantum restoration of broken symmetry in ... Keywords. Non-local transformation; broken symmetry; sine-Gordon; sech interaction. ... A specific type of classically broken symmetry is restored in quantum theory. One-dimensional sine-Gordon system and ...
Effective theories with broken flavour symmetry
International Nuclear Information System (INIS)
Miller, R.D.C.; McKellar, B.H.J.
1981-07-01
The work of Ovrut and Schnitzer on effective theories derived from a non Abelian Gauge Theory is generalised to include the physically interesting case of broken flavour symmetry. The calculations are performed at the 1-loop level. It is shown that at an intermediate stage in the calculations two distinct renormalised gauge coupling constants appear, one describing gauge field coupling to heavy particles and the other describing coupling to light particles. Appropriately modified Slavnov-Taylor identities are shown to hold. A simple alternative to the Ovrut-Schnitzer rules for calculating with effective theories is also considered
Broken symmetries and the Cabibbo angle
International Nuclear Information System (INIS)
Lanik, J.
1975-04-01
Under the assumption that the SU(3) symmetry is broken down by the strong and electromagnetic interactions, a phenomenological theory of the Cabibbo angle theta is proposed. In this theory the angle theta is fixed, linking together the Cabibbo rotation in the SU(3) space and complete SU(3) breaking consisting of both the SU(3) Hamiltonian and vacuum non-invariances. Assuming that the value of theta is zero in the soft-pion limit and that, in this limit, the only forces responsible for the isotopic symmetry breaking are the usual photonic forces it is shown that the usual electromagnetic interactions can contribute for the value of theta only through the non-vanishing vacuum expectation value of a certain scalar field. Within the framework of the (3,average3)+(3,average3) chiral symmetry-breaking model and through the use of the experimental value of the ratio GAMMA (K→μν)/GAMMA(π→μν), the presented Cabibbo angle theory predicts the value sintheta=0.25 which is in good agreement with experiment. (Lanik, J.)
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...... be provided with sonic internal structure realizing such a velocity- or force-friction dependence. For demonstration of a ratchet mechanism of this type, an experimental setup (gadget) that converts longitudinal oscillating or fluctuating motion into a unidirectional rotation has been built and experiments...... with it have been carried out. In this device, an asymmetry of friction dependence on an applied force appears, resulting in rectification of rotary motion, In experiments, our setup is observed to rotate only in one direction, which is in accordance with given theoretical arguments, Despite the setup being...
Neutrino mixing: from the broken μ-τ symmetry to the broken Friedberg–Lee symmetry
International Nuclear Information System (INIS)
Xing, Zhizhong
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 μ-τ permutation symmetry serves for such an example to interpret the almost maximal atmospheric neutrino mixing angle (θ 23 ~ 45°) and the strongly suppressed CHOOZ neutrino mixing angle (θ 13 < 10°). 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 θ 13 in the CP-conserving case: sinθ 13 = tanθ 12 |(1 - tanθ 23 )/(1 + tanθ 23 )|. 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. (author)
Superconducting cosmic strings in models with spontaneously broken family symmetry
International Nuclear Information System (INIS)
Bibilashvili, T.M.; Dvali, G.R.
1990-01-01
It is shown that superconducting cosmic strings with some specific properties naturally exist in models of spontaneously broken family symmetry. Superconductivity may be of both types - bosonic and fermionic. There exists a possible mechanism of string conservation. (orig.)
Symmetry restoration in spontaneously broken induced gravity
International Nuclear Information System (INIS)
Amati, D.; Russo, J.
1990-01-01
We investigate the recuperation of expected invariant behaviours in a non-metric gravity theory in which the full general relativistic invariance is broken spontaneously. We show how dangerous increasing energy behaviours of physical amplitudes cancel in a highly non-trivial way. This evidences the expected loss of the vacuum generated scale in the UV regime and gives support for the consistency of spontaneously broken gravity theories. (orig.)
Multiquark baryons with broken flavour symmetry 1
International Nuclear Information System (INIS)
Wroldsen, J.
The calculation of the spectrum of 4qq multiquark baryons is carried out, taking into account that SU(3) flavour is broken. To handle this problem, which includes manipulation of giant expressions for the wavefunctions, methods suitable for programming in SCHOONSCHIP are developed and employed. (Auth)
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
Kolb, Edward W; Vallinotto, A; Kolb, Edward W.; Riotto, Antonio; Vallinotto, Alberto
2006-01-01
Recently we studied inflation models in which the inflaton 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, $f_{NL}$, can be as large as 10^2.
Weak interaction models with spontaneously broken left-right symmetry
International Nuclear Information System (INIS)
Mohapatra, R.H.
1978-01-01
The present status of weak interaction models with spontaneously broken left-right symmetry is reviewed. The theoretical basis for asymptotic parity conservation, manifest left-right symmetry in charged current weak interactions, natural parity conservation in neutral currents and CP-violation in the context of SU(2)/sub L/ circled x SU (2)/sub R/ circled x U(1) models are outlined in detail. Various directions for further research in the theoretical and experimental side are indicated
Discrete symmetries: A broken look at QCD
International Nuclear Information System (INIS)
Goldman, T.
1996-01-01
The alphabet soup of discrete symmetries is briefly surveyed with a view towards those which can be tested at LISS and two particularly interesting cases are called out. A LISS experiment may be able to distinguish CP violation that is not due to the QCD θ term. The elements of a model of parity violation in proton-nucleon scattering, which is consistent with lower energy LAMPF and ANL results, are reviewed in the light of new information on diquarks and the proton spin fraction carried by quarks. The prediction that the parity violating total cross section asymmetry should be large at LISS energies is confirmed. The results of such an experiment can be used both to obtain new information about the diquark substructure of the nucleon and to provide bounds on new right-chiral weak interactions
Light hadrons in the bag model with broken chiral symmetry
International Nuclear Information System (INIS)
Efrosinin, V.P.; Zaikin, D.A.
1987-01-01
A version of the bag model with broken chiral symmetry is proposed. A satisfactory description of the experimental data on light hadrons including the pion is obtained. The estimate of the pion-nucleon σ term is given in the framework of this model. The pion and kaon decay constants are calculated. The centre-of-mass motion problem in bag models is discussed
Spontaneous Broken Local Conformal Symmetry and Dark Energy Candidate
International Nuclear Information System (INIS)
Liu, Lu-Xin
2013-01-01
The local conformal symmetry is spontaneously broken down to the Local Lorentz invariance symmetry through the approach of nonlinear realization. The resulting effective Lagrangian, in the unitary gauge, describes a cosmological vector field non-minimally coupling to the gravitational field. As a result of the Higgs mechanism, the vector field absorbs the dilaton and becomes massive, but with an independent energy scale. The Proca type vector field can be modelled as dark energy candidate. The possibility that it further triggers Lorentz symmetry violation is also pointed out
Heavy axions from strong broken horizontal gauge symmetry
International Nuclear Information System (INIS)
Elliott, T.; King, S.F.
1993-01-01
We study the consequences of the existence and breaking of a Peccei-Quinn symmetry within the context of a dynamical model of electroweak symmetry breaking based on broken gauged flavour symmetries. We perform an estimate of the axion mass by including flavour instanton effects and show that, for low cut-offs, the axion is sufficiently massive to prevent it from being phenomenologically unacceptable. We conclude with an examination of the strong CP problem and show that our axion cannot solve the problem, though we indicate ways in which the model can be extended so that the strong CP problem is solved. (orig.)
Conformal bootstrap with slightly broken higher spin symmetry
Energy Technology Data Exchange (ETDEWEB)
Alday, Luis F. [Mathematical Institute, University of Oxford,Andrew Wiles Building, Radcliffe Observatory Quarter,Woodstock Road, Oxford, OX2 6GG (United Kingdom); Zhiboedov, Alexander [Center for the Fundamental Laws of Nature,Harvard University, Cambridge, MA 02138 (United States)
2016-06-16
We consider conformal field theories with slightly broken higher spin symmetry in arbitrary spacetime dimensions. We analyze the crossing equation in the double light-cone limit and solve for the anomalous dimensions of higher spin currents γ{sub s} with large spin s. The result depends on the symmetries and the spectrum of the unperturbed conformal field theory. We reproduce all known results and make further predictions. In particular we make a prediction for the anomalous dimensions of higher spin currents in the 3d Ising model.
Massive Kaluza-Klein theories and their spontaneously broken symmetries
International Nuclear Information System (INIS)
Hohm, O.
2006-07-01
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 3 x S 3 x S 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 3 x S 3 x S 3 and the corresponding symmetry breakings are analyzed as possible applications for the AdS/CFT correspondence. (Orig.)
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.)
Entanglement entropy in quantum spin chains with broken reflection symmetry
International Nuclear Information System (INIS)
Kadar, Zoltan; Zimboras, 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 are calculated analytically for general gauge-invariant models, which have, until now, been done only for the reflection-symmetric sector. Analytical results are also derived for certain nongauge-invariant models (e.g., for the Ising model with Dzyaloshinskii-Moriya interaction). We also study numerically finite chains of length N with a nonreflection-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, for noncritical reflection-symmetry-breaking Hamiltonians, we find an anomaly in the behavior of the saturation entropy as we approach the critical line. The paper also provides a concise but extensive review of the block-entropy asymptotics in translation-invariant quasifree spin chains with an analysis of the nearest-neighbor case and the enumeration of the yet unsolved parts of the quasifree landscape.
Spontaneously broken spacetime symmetries and the role of inessential Goldstones
Klein, Remko; Roest, Diederik; Stefanyszyn, David
2017-10-01
In contrast to internal symmetries, there is no general proof that the coset construction for spontaneously broken spacetime symmetries leads to universal dynamics. One key difference lies in the role of Goldstone bosons, which for spacetime symmetries includes a subset which are inessential for the non-linear realisation and hence can be eliminated. In this paper we address two important issues that arise when eliminating inessential Goldstones. The first concerns the elimination itself, which is often performed by imposing so-called inverse Higgs constraints. Contrary to claims in the literature, there are a series of conditions on the structure constants which must be satisfied to employ the inverse Higgs phenomenon, and we discuss which parametrisation of the coset element is the most effective in this regard. We also consider generalisations of the standard inverse Higgs constraints, which can include integrating out inessential Goldstones at low energies, and prove that under certain assumptions these give rise to identical effective field theories for the essential Goldstones. Secondly, we consider mappings between non-linear realisations that differ both in the coset element and the algebra basis. While these can always be related to each other by a point transformation, remarkably, the inverse Higgs constraints are not necessarily mapped onto each other under this transformation. We discuss the physical implications of this non-mapping, with a particular emphasis on the coset space corresponding to the spontaneous breaking of the Anti-De Sitter isometries by a Minkowski probe brane.
Two phases of the anyon gas and broken T symmetry
International Nuclear Information System (INIS)
Canright, G.S.; Rojo, A.G.
1991-01-01
This paper reports the first exact finite-temperature study of anyons. The authors' method is an extension to finite T of earlier numerical work with small numbers of anyons on a lattice. We study the spontaneous magnetization M 0 (T), since the signature has been identified as a key signature of broken T symmetry for anyon models. Our results confirm the two-phase picture suggested by earlier work: The authors find a low-temperature regime where M 0 is very small or zero, and a high-temperature regime where M 0 is of O(0.1 μ B ) per particle. In the high-temperature regime the authors can obtain an excellent estimate of M 0 (T) in the thermodynamic limit (which we call M 0 ∞ ). since our finite-size results extrapolate smoothly with little scatter. The authors' values for M 0 ∞ can then be compared with the results of μSR experiments on high-temperature superconductors, which set an upper experimental bound on the internal fields from such moments. The authors find that M 0 ∞ in a bulk material of many planes will almost certainly give a signal well above this threshold if (and only if) the planes are ordered ferromagnetically. In the antiferromagnetic case (which is strongly favored energetically) the signal from M 0 ∞ is probably undetectable. Finally, we estimate the transition temperature T c from our finite-size studies, obtaining a value on the order of a few hundred Kelvins
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
Gauge-Higgs unification with broken flavour symmetry
International Nuclear Information System (INIS)
Olschewsky, M.
2007-05-01
We study a five-dimensional Gauge-Higgs unification model on the orbifold S 1 /Z 2 based on the extended standard model (SM) gauge group SU(2) L x U(1) Y x SO(3) F . The group SO(3) 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) L x U(1) Y x SO(3) F by orbifolding and imposing Dirichlet and Neumann boundary conditions. The compactification scale of the theory is O(1) TeV. Furthermore, the orbifold S 1 /Z 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(Φ) emerges naturally. The PTs can be written as a product e A y e η e A y of unitary factors e A y and a selfadjoint factor e η . The reduction 48 → 35 + 6 + anti 6 + 1 of the adjoint representation of SU(7) with respect to SU(6) contains SU(2) L x U(1) Y x SO(3) F leads to three SU(2) 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) L x U(1) Y x SO(3) F is spontaneously broken down to U(1) em , an exponential gauge boson mass splitting occurs naturally. At a first step SU(2) L x U(1) Y x SO(3) F is broken to SU(2) L x U(1) Y by VEVs for the selfadjoint factor e η . This breaking leads to masses of flavour changing SO(3) F gauge bosons much above the compactification scale. Such a behaviour has no counterpart within the customary approximation scheme of an ordinary orbifold theory. This way tree
Finite-temperature effective potential of a system with spontaneously broken symmetry
Energy Technology Data Exchange (ETDEWEB)
Zemskov, E.P. [Yaroslavl State Technical Univ. (Russian Federation)
1995-12-01
A quantum-mechanical system with spontaneously broken symmetry is considered the effective potential is determined, and it is shown that with reduction of temperature the system undergoes a phase transition of the first kind.
Broken dynamical symmetries in quantum mechanics and phase transition phenomena
International Nuclear Information System (INIS)
Guenther, N.J.
1979-12-01
This thesis describes applications of dynamical symmetries to problems in quantum mechanics and many-body physics where the latter is formulated as a Euclidean scalar field theory in d-space dimensions. By invoking the concept of a dynamical symmetry group a unified understanding of apparently disparate results is achieved. (author)
Fluctuation relations for equilibrium states with broken discrete or continuous symmetries
International Nuclear Information System (INIS)
Lacoste, D; Gaspard, P
2015-01-01
Isometric fluctuation relations are deduced for the fluctuations of the order parameter in equilibrium systems of condensed-matter physics with broken discrete or continuous symmetries. These relations are similar to their analogues obtained for non-equilibrium systems where the broken symmetry is time reversal. At equilibrium, these relations show that the ratio of the probabilities of opposite fluctuations goes exponentially with the symmetry-breaking external field and the magnitude of the fluctuations. These relations are applied to the Curie–Weiss, Heisenberg, and XY models of magnetism where the continuous rotational symmetry is broken, as well as to the q-state Potts model and the p-state clock model where discrete symmetries are broken. Broken symmetries are also considered in the anisotropic Curie–Weiss model. For infinite systems, the results are calculated using large-deviation theory. The relations are also applied to mean-field models of nematic liquid crystals where the order parameter is tensorial. Moreover, their extension to quantum systems is also deduced. (paper)
Nonreciprocal Linear Transmission of Sound in a Viscous Environment with Broken P Symmetry
Walker, E.; Neogi, A.; Bozhko, A.; Zubov, Yu.; Arriaga, J.; Heo, H.; Ju, J.; Krokhin, A. A.
2018-05-01
Reciprocity is a fundamental property of the wave equation in a linear medium that originates from time-reversal symmetry, or T symmetry. For electromagnetic waves, reciprocity can be violated by an external magnetic field. It is much harder to realize nonreciprocity for acoustic waves. Here we report the first experimental observation of linear nonreciprocal transmission of ultrasound through a water-submerged phononic crystal consisting of asymmetric rods. Viscosity of water is the factor that breaks the T symmetry. Asymmetry, or broken P symmetry along the direction of sound propagation, is the second necessary factor for nonreciprocity. Experimental results are in agreement with numerical simulations based on the Navier-Stokes equation. Our study demonstrates that a medium with broken PT symmetry is acoustically nonreciprocal. The proposed passive nonreciprocal device is cheap, robust, and does not require an energy source.
Broken SU(8) symmetry and the new particles
International Nuclear Information System (INIS)
Kramer, G.; Schiller, D.H.
1976-05-01
We study the mass spectra and wave functions for vector and pseudoscalar mesons in broken SU(8) (SU(8) is contained in SU(4)F * SU(2)J), where F stands for flavour and J for usual spin. The connection with the standard mass breaking in SU(4)F is worked out. We find that even in the presence of strong SU(8) breaking the ideal mixing scheme for the vector mesons can be approximately retained. For the pseudoscalar mesons the mixing of the singlet with the 63-plet representation of SU(8) turns out to be essential and stongly nonideal. (orig.) [de
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.
Broken chiral symmetry and the structure of hadrons
International Nuclear Information System (INIS)
Spence, W.L.
1982-01-01
The spontaneous breaking of chiral symmetry plays a decisive role in the structure of hadrons composed of light quarks. The formalism by which the dynamics of chiral symmetry breaking and its implications for hadronic structure can be explored in a simplified world in which fully relativistic zero-bare-mass quarks interact through a chirally symmetric instantaneous confining potential is presented. By thus modeling the essentials of the chiral limit-N/sub c/ infinity limit of QCD contact is made with the successes of existent semiphenomenological models of hadrons but post assumptions which explicitly violate chiral symetry are avoided. This revised approach then makes possible a unification of the dynamics of hadron structure with the mechanism of spontaneous chiral breaking and guarantees the appearance of the correct Goldstone excitations. The chiral breaking order parameter (absolute value anti psi psi), effective quark mass, and Goldstone boson wave function are obtainable by solving a single non-linear integral equation once a potential has been prescribed. The stability of the chiral asymmetric vacuum must then be established by studying the linear eigenvalue problem which determines the spectrum of states with vacuum quantum numbers. The nature of the instability of the chiral symmetric vacuum that leads to spontaneous symmetry breaking is explained and its apparent contingency on details of the dynamics is emphasized. It is argued that a single massless fermion in a chirally symmetric potential does form bound states for which a semi-classical description is given. Coupling to vacuum pairs of such bound states occasions the possibility of chiral symmetry breakdown
Contraction of broken symmetries via Kac-Moody formalism
International Nuclear Information System (INIS)
Daboul, Jamil
2006-01-01
I investigate contractions via Kac-Moody formalism. In particular, I show how the symmetry algebra of the standard two-dimensional Kepler system, which was identified by Daboul and Slodowy as an infinite-dimensional Kac-Moody loop algebra, and was denoted by H 2 , gets reduced by the symmetry breaking term, defined by the Hamiltonian H(β)=(1/2m)(p 1 2 +p 2 2 )-α/r-βr -1/2 cos((φ-γ)/2). For this H(β) I define two symmetry loop algebras L i (β), i=1,2, by choosing the 'basic generators' differently. These L i (β) can be mapped isomorphically onto subalgebras of H 2 , of codimension two or three, revealing the reduction of symmetry. Both factor algebras L i (β)/I i (E,β), relative to the corresponding energy-dependent ideals I i (E,β), are isomorphic to so(3) and so(2,1) for E 0, respectively, just as for the pure Kepler case. However, they yield two different nonstandard contractions as E→0, namely to the Heisenberg-Weyl algebra h 3 =w 1 or to an Abelian Lie algebra, instead of the Euclidean algebra e(2) for the pure Kepler case. The above-noted example suggests a general procedure for defining generalized contractions, and also illustrates the 'deformation contraction hysteresis', where contraction which involves two contraction parameters can yield different contracted algebras, if the limits are carried out in different order
Jang, Iksu; Kim, Ki-Seok
2018-04-01
Anomaly cancellation has been shown to occur in broken time-reversal symmetry Weyl metals, which explains the existence of a Fermi arc. We extend this result in the case of broken inversion symmetry Weyl metals. Constructing a minimal model that takes a double pair of Weyl points, we demonstrate the anomaly cancellation explicitly. This demonstration explains why a chiral pair of Fermi arcs appear in broken inversion symmetry Weyl metals. In particular, we find that this pair of Fermi arcs gives rise to either "quantized" spin Hall or valley Hall effects, which corresponds to the "quantized" version of the charge Hall effect in broken time-reversal symmetry Weyl metals.
Broken Weyl symmetry. [Gauge model, coupling, Higgs field
Energy Technology Data Exchange (ETDEWEB)
Domokos, G.
1976-05-01
It is argued that conformal symmetry can be properly understood in the framework of field theories in curved space. In such theories, invariance is required under general coordinate transformations and conformal rescalings. A gauge model coupled to a Higgs field is examined. In the tree approximation, the vacuum solution exhibits two Higgs phenomena; both the phase (Goldstone boson) and the coordinate dependent part of the radial component of the scalar field can be removed by a Higgs-Kibble transformation. The resulting vacuum solution corresponds to a space of constant curvature and constant vacuum expectation value of the scalar field.
Interface properties of superlattices with artificially broken symmetry
International Nuclear Information System (INIS)
Lottermoser, Th.; Yamada, H.; Matsuno, J.; Arima, T.; Kawasaki, M.; Tokura, Y.
2007-01-01
We have used superlattices made of thin layers of transition metal oxides to design the so-called multiferroics, i.e. materials possessing simultaneously an electric polarization and a magnetic ordering. The polarization originates from the asymmetric stacking order accompanied by charge transfer effects, while the latter one also influences the magnetic properties of the interfaces. Due to the breaking of space and time-reversal symmetry by multiple ordering mechanism magnetic second harmonic generation is proven to be an ideal method to investigate the electric and magnetic properties of the superlattices
On hierarchy in asymptotic reconstruction of spontaneously broken isotopic symmetry
International Nuclear Information System (INIS)
Ermolaev, B.I.
1978-01-01
The isotopic features of the effective current-current lagrangian of the Lsub(eff) electromagnetic-weak interaction between elementary particles are treated at large momentum transfers using the Weinberg-Salam model. Transition to other models may be made by analogy. It is shown that when the collision energies of elementary particles exceed 90 GeV one may expect the hierarchy in the asymptotic reconstruction of the isotopic symmetry. Such hierarchy could be observed, in particular, in experiments on elastic leptonic collisions at high energies
Broken symmetry in a two-qubit quantum control landscape
Bukov, Marin; Day, Alexandre G. R.; Weinberg, Phillip; Polkovnikov, Anatoli; Mehta, Pankaj; Sels, Dries
2018-05-01
We analyze the physics of optimal protocols to prepare a target state with high fidelity in a symmetrically coupled two-qubit system. By varying the protocol duration, we find a discontinuous phase transition, which is characterized by a spontaneous breaking of a Z2 symmetry in the functional form of the optimal protocol, and occurs below the quantum speed limit. We study in detail this phase and demonstrate that even though high-fidelity protocols come degenerate with respect to their fidelity, they lead to final states of different entanglement entropy shared between the qubits. Consequently, while globally both optimal protocols are equally far away from the target state, one is locally closer than the other. An approximate variational mean-field theory which captures the physics of the different phases is developed.
Broken flavor symmetries in high energy particle phenomenology
International Nuclear Information System (INIS)
Antaramian, A.
1995-01-01
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.
The energy-momentum spectrum in local field theories with broken Lorentz-symmetry
International Nuclear Information System (INIS)
Borchers, H.J.; Buchholz, D.
1984-05-01
Assuming locality of the observables and positivity of the energy it is shown that the joint spectrum of the energy-momentum operators has a Lorentz-invariant lower boundary in all superselection sectors. This result is of interest if the Lorentz-symmetry is (spontaneously) broken, such as in the charged sectors of quantum electrodynamics. (orig.)
International Nuclear Information System (INIS)
Ezawa, Motohiko
2014-01-01
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 −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.
Localized surface plasmon resonance properties of symmetry-broken Au-ITO-Ag multilayered nanoshells
Lv, Jingwei; Mu, Haiwei; Lu, Xili; Liu, Qiang; Liu, Chao; Sun, Tao; Chu, Paul K.
2018-06-01
The plasmonic properties of symmetry-broken Au-ITO-Ag multilayered nanoshells by shell cutting are studied by the finite element method. The influence of the polarization of incident light and geometrical parameters on the plasmon resonances of the multilayered nanoshells are investigated. The polarization-dependent multiple plasmon resonances appear from the multilayered nanoshells due to symmetry breaking. In nanostructures with a broken symmetry, the localized surface plasmon resonance modes are enhanced resulting in higher order resonances. According to the plasmon hybridization theory, these resonance modes and greater spectral tunability derive from the interactions of an admixture of both primitive and multipolar modes between the inner Au core and outer Ag shell. By changing the radius of the Au core, the extinction resonance modes of the multilayered nanoshells can be easily tuned to the near-infrared region. To elucidate the symmetry-broken effects of multilayered nanoshells, we link the geometrical asymmetry to the asymmetrical distributions of surface charges and demonstrate dipolar and higher order plasmon modes with large associated field enhancements at the edge of the Ag rim. The spectral tunability of the multiple resonance modes from visible to near-infrared is investigated and the unique properties are attractive to applications including angularly selective filtering to biosensing.
Remarks on broken chiral SU(5) x SU(5) symmetry and B mesons
International Nuclear Information System (INIS)
Kim, D.Y.; Sinha, S.N.
1985-01-01
In a recent paper, Hatzis has estimated the masses and weak decay constants of b-flavored pseudoscalar mesons in a broken chiral SU(5) x SU(5) symmetry method. The estimated weak decay constant of B meson, f sub(B) f sub(K)(f sub(B)/f sub(K) approximately equal to 1.4) evaluated by Mathur et al. with the quantum chromodynamics (QCD) sum-rule model. We re-examined the problem applying the broken chiral SU(5) x SU(5) symmetry approach using a set of mass formulae. With this method we estimate the symmetry-breaking parameters and decay constants of pseudoscalar mesons. We found a consistent result for the decay constant: f sub(K) < or approximately equal to f sub(D) < or approximately equal to f sub(B). The explicit numerical value of these constants, however, are lower than that of the QCD sum rule. This may be due to the limited validity of the broken chiral symmetry approach for heavy mesons
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 symmetries at high temperatures and the problem of baryon excess of the universe
International Nuclear Information System (INIS)
Mohapatra, R.N.; Senjanovic, G.
1979-06-01
A class of gauge theories, where spontaneously broken symmetries, instead of being restored, persist as the temperature is increased is discussed. A renormalization group analysis of this phenomena suggests that there may be more than one phase transition in these models with at least one symmetric phase. Applying these ideas to the specific case of soft CP-violation in grand unified theories, a mechanism to generate the baryon to entropy ratio of the universe is discussed. 34 references
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.
International Nuclear Information System (INIS)
Craigie, N.S.; Salam, Abdus
1979-05-01
The effect of scalar partons arising in QCD if the colour symmetry is spontaneously broken is discussed. The authors use a previous result, which states that such scalars can be incorporated into the theory without disturbing asymptotic freedom. (author)
Symmetry broken and restored coupled-cluster theory: I. Rotational symmetry and angular momentum
International Nuclear Information System (INIS)
Duguet, T
2015-01-01
We extend coupled-cluster (CC) theory performed on top of a Slater determinant breaking rotational symmetry to allow for the exact restoration of the angular momentum at any truncation order. The main objective relates to the description of near-degenerate finite quantum systems with an open-shell character. As such, the newly developed many-body formalism offers a wealth of potential applications and further extensions dedicated to the ab initio description of, e.g., doubly open-shell atomic nuclei and molecule dissociation. The formalism, which encompasses both single-reference CC theory and projected Hartree–Fock theory as particular cases, permits the computation of usual sets of connected diagrams while consistently incorporating static correlations through the highly non-perturbative restoration of rotational symmetry. Interestingly, the yrast spectroscopy of the system, i.e. the lowest energy associated with each angular momentum, is accessed within a single calculation. A key difficulty presently overcome relates to the necessity to handle generalized energy and norm kernels for which naturally terminating CC expansions could be eventually obtained. The present work focuses on SU(2) but can be extended to any (locally) compact Lie group and to discrete groups, such as most point groups. In particular, the formalism will be soon generalized to U(1) symmetry associated with particle number conservation. This is relevant to Bogoliubov CC theory that was recently applied to singly open-shell nuclei. (paper)
Spontaneously broken continuous symmetries in hyperbolic (or open) de Sitter spacetime
International Nuclear Information System (INIS)
Ratra, B.
1994-01-01
The functional Schroedinger approach is used to study scalar field theory in hyperbolic (or open) de Sitter spacetime. While on intermediate length scales (small compared to the spatial curvature length scale) the massless minimally coupled scalar field two-point correlation function does have a term that varies logarithmically with scale, as in flat and closed de Sitter spacetime, the spatial curvature tames the infrared behavior of this correlation function at larger scales in the open model. As a result, and contrary to what happens in flat and closed de Sitter spacetime, spontaneously broken continuous symmetries are not restored in open de Sitter spacetime (with more than one spatial dimension)
International Nuclear Information System (INIS)
Halpern, L.
1981-01-01
Invariant varieties of suitable semisimple groups of transformations can serve as models of the space-time of the universe. The metric is expressible in terms of the basis vectors of the group. The symmetry of the group is broken by introducing a gauge formalism in the space of the basis vectors with the adjoint group as gauge group. The gauge potentials are expressible in terms of the basis vectors for the case of the De Sitter group. The resulting gauge theory is equivalent to De Sitter covariant general relativity. Group covariant generalizations of gravitational theory are discussed. (Auth.)
Colak, Evrim; Serebryannikov, Andriy E.; Ozgur Cakmak, A.; Ozbay, Ekmel
2013-04-01
It is experimentally demonstrated that the combination of diode and splitter functions can be realized in one broadband reciprocal device. The suggested performance is based on the dielectric photonic crystal grating whose structural symmetry is broken owing to non-deep corrugations placed at one of the two interfaces. The study has been performed at a normally incident beam-type illumination obtained from a microwave horn antenna. The two unidirectionally transmitted, deflected beams can show large magnitude and high contrast, while the angular distance between their maxima is 90° and larger. The dual-band unidirectional splitting is possible when using TM and TE polarizations.
International Nuclear Information System (INIS)
Damski, Bogdan; Zurek, Wojciech H
2008-01-01
We discuss the dynamics of a quantum phase transition in a spin-1 Bose-Einstein condensate when it is driven from the magnetized broken-symmetry phase to the unmagnetized 'symmetric' polar phase. We determine where the condensate goes out of equilibrium as it approaches the critical point, and compute the condensate magnetization at the critical point. This is done within a quantum Kibble-Zurek scheme traditionally employed in the context of symmetry-breaking quantum phase transitions. Then we study the influence of the non-equilibrium dynamics near a critical point on the condensate magnetization. In particular, when the quench stops at the critical point, nonlinear oscillations of magnetization occur. They are characterized by a period and an amplitude that are inversely proportional. If we keep driving the condensate far away from the critical point through the unmagnetized 'symmetric' polar phase, the amplitude of magnetization oscillations slowly decreases reaching a nonzero asymptotic value. That process is described by an equation that can be mapped onto the classical mechanical problem of a particle moving under the influence of harmonic and 'anti-friction' forces whose interplay leads to surprisingly simple fixed-amplitude oscillations. We obtain several scaling results relating the condensate magnetization to the quench rate, and verify numerically all analytical predictions
International Nuclear Information System (INIS)
Ryu, S.; Furusaki, A.; Ludwig, A.W.W.; Mudry, C.
2007-01-01
We extend the analysis of the conductance fluctuations in disordered metals by Altshuler, Kravtsov, and Lerner (AKL) to disordered superconductors with broken time-reversal symmetry in d=(2+ε) dimensions (symmetry classes C and D of Altland and Zirnbauer). Using a perturbative renormalization group analysis of the corresponding non-linear sigma model (NLσM) we compute the anomalous scaling dimensions of the dominant scalar operators with 2s gradients to one-loop order. We show that, in analogy with the result of AKL for ordinary, metallic systems (Wigner-Dyson classes), an infinite number of high-gradient operators would become relevant (in the renormalization group sense) near two dimensions if contributions beyond one-loop order are ignored. We explore the possibility to compare, in symmetry class D, the ε=(2-d) expansion in d<2 with exact results in one dimension. The method we use to perform the one-loop renormalization analysis is valid for general symmetric spaces of Kaehler type, and suggests that this is a generic property of the perturbative treatment of NLσMs defined on Riemannian symmetric target spaces
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.
New Boundary-Driven Twist States in Systems with Broken Spatial Inversion Symmetry
Hals, Kjetil M. D.; Everschor-Sitte, Karin
2017-09-01
A full description of a magnetic sample includes a correct treatment of the boundary conditions (BCs). This is in particular important in thin film systems, where even bulk properties might be modified by the properties of the boundary of the sample. We study generic ferromagnets with broken spatial inversion symmetry and derive the general micromagnetic BCs of a system with Dzyaloshinskii-Moriya interaction (DMI). We demonstrate that the BCs require the full tensorial structure of the third-rank DMI tensor and not just the antisymmetric part, which is usually taken into account. Specifically, we study systems with C∞ v symmetry and explore the consequences of the DMI. Interestingly, we find that the DMI already in the simplest case of a ferromagnetic thin film leads to a purely boundary-driven magnetic twist state at the edges of the sample. The twist state represents a new type of DMI-induced spin structure, which is completely independent of the internal DMI field. We estimate the size of the texture-induced magnetoresistance effect being in the range of that of domain walls.
Fibre multi-wave mixing combs reveal the broken symmetry of Fermi-Pasta-Ulam recurrence
Mussot, Arnaud; Naveau, Corentin; Conforti, Matteo; Kudlinski, Alexandre; Copie, Francois; Szriftgiser, Pascal; Trillo, Stefano
2018-05-01
In optical fibres, weak modulations can grow at the expense of a strong pump to form a triangular comb of sideband pairs, until the process is reversed. Repeated cycles of such conversion and back-conversion constitute a manifestation of the universal nonlinear phenomenon known as Fermi-Pasta-Ulam recurrence. However, it remains a major challenge to observe the coexistence of different types of recurrences owing to the spontaneous symmetry-breaking nature of such a phenomenon. Here, we implement a novel non-destructive technique that allows the evolution in amplitude and phase of frequency modes to be reconstructed via post-processing of the fibre backscattered light. We clearly observe how control of the input modulation seed results in different recursive behaviours emerging from the phase-space structure dictated by the spontaneously broken symmetry. The proposed technique is an important tool to characterize other mixing processes and new regimes of rogue-wave formation and wave turbulence in fibre optics.
International Nuclear Information System (INIS)
Bonanno, Luca; Drago, Alessandro
2009-01-01
We study matter at high density and temperature using a chiral Lagrangian in which the breaking of scale invariance is regulated by the value of a scalar field, called dilaton [E. K. Heide, S. Rudaz, and P. J. Ellis, Nucl. Phys. A571, 713 (1994); G. W. Carter, P. J. Ellis, and S. Rudaz, Nucl. Phys. A603, 367 (1996); G. W. Carter, P. J. Ellis, and S. Rudaz, Nucl. Phys. A618, 317 (1997); G. W. Carter and P. J. Ellis, Nucl. Phys. A628, 325 (1998)]. We provide a phase diagram describing the restoration of chiral and scale symmetries. We show that chiral symmetry is restored at large temperatures, but at low temperatures it remains broken at all densities. We also show that scale invariance is more easily restored at low rather than large baryon densities. The masses of vector-mesons scale with the value of the dilaton and their values initially slightly decrease with the density but then they increase again for densities larger than ∼3ρ 0 . The pion mass increases continuously with the density and at ρ 0 and T=0 its value is ∼30 MeV larger than in the vacuum. We show that the model is compatible with the bounds stemming from astrophysics, as, e.g., the one associated with the maximum mass of a neutron star. The most striking feature of the model is a very significant softening at large densities, which manifests also as a strong reduction of the adiabatic index. Although the softening has probably no consequence for supernova explosion via the direct mechanism, it could modify the signal in gravitational waves associated with the merging of two neutron stars.
Study of spontaneously broken conformal symmetry in curved space-times
International Nuclear Information System (INIS)
Janson, M.M.
1977-05-01
Spontaneous breakdown of Weyl invariance (local scale invariance) in a conformally-invariant extension of a gauge model for weak and electromagnetic interactions is considered. The existence of an asymmetric vacuum for the Higgs field, phi, is seen to depend on the space-time structure via the Gursey-Penrose term, approximately phi + phi R, in the action. (R denotes the scalar curvature.) The effects of a prescribed space-time structure on spontaneously broken Weyl invariance is investigated. In a cosmological space-time, it is found that initially, in the primordial fireball, the symmetry must hold exactly. Spontaneous symmetry breaking (SSB) develops as the universe expands and cools. Consequences of this model include a dependence of G/sub F/, the effective weak interaction coupling strength, on ''cosmic time.'' It is seen to decrease monotonically; in the present epoch (G/sub F//G/sub F/)/sub TODAY/ approximately less than 10 -10 (year) -1 . The effects of the Schwarzschild geometry on SSB are explored. In the interior of a neutron star the Higgs vacuum expectation value, and consequently G/sub F/, is found to have a radial dependence. The magnitude of this variation does not warrant revision of present models of neutron star structures. Another perspective on the problem considered a theory of gravitation (conformal relativity) to be incorporated in the conformally invariant gauge model of weak and electromagnetic interactions. If SSB develops, the vacuum gravitational field equations are the Einstein field equations with a cosmological constant. The stability of the asymmetric vacuum solution is investigated to ascertain whether SSB can occur
Hong, R.; Li, J. C.; Hajjar, R.; Chakraborty Thakur, S.; Diamond, P. H.; Tynan, G. R.
2018-05-01
Detailed measurements of intrinsic axial flow generation parallel to the magnetic field in the controlled shear decorrelation experiment linear plasma device with no axial momentum input are presented and compared to theory. The results show a causal link from the density gradient to drift-wave turbulence with broken spectral symmetry and development of the axial mean parallel flow. As the density gradient steepens, the axial and azimuthal Reynolds stresses increase and radially sheared azimuthal and axial mean flows develop. A turbulent axial momentum balance analysis shows that the axial Reynolds stress drives the radially sheared axial mean flow. The turbulent drive (Reynolds power) for the azimuthal flow is an order of magnitude greater than that for axial flow, suggesting that the turbulence fluctuation levels are set by azimuthal flow shear regulation. The direct energy exchange between axial and azimuthal mean flows is shown to be insignificant. Therefore, the axial flow is parasitic to the turbulence-zonal flow system and is driven primarily by the axial turbulent stress generated by that system. The non-diffusive, residual part of the axial Reynolds stress is found to be proportional to the density gradient and is formed due to dynamical asymmetry in the drift-wave turbulence.
A solution to the rho-π puzzle: Spontaneously broken symmetries of the quark model
International Nuclear Information System (INIS)
Caldi, D.G.; Pagels, H.
1976-01-01
This article proposes a solution to the long-standing rho-π puzzle: How can the rho and π be members of a quark model U(6) 36 and the π be a Nambu-Goldstone boson satisfying partial conservation of the axial-vector current (PCAC) Our solution to the puzzle requires a revision of conventional concepts regarding the vector mesons rho, ω, K*, and phi. Just as the π is a Goldstone state, a collective excitation of the Nambu--Jona-Lasinio type, transforming as a member of the (3, 3) + (3, 3) representation of the chiral SU(3) x SU(3) group, so also the rho transforms like (3, 3) + (3, 3) and is also a collective state, a ''dormant'' Goldstone boson that is a true Goldstone boson in the static chiral U(6) x U(6) limit. The static chiral U(6) x U(6) is to be spontaneously broken to static U(6) in the vacuum. Relativisitc effects provide for U(6) breaking and a massive rho. This viewpoint has many consequences. Vector-meson dominance is a consequence of spontaneously broken chiral symmetry: the mechanism that couples the axial-vector current to the π couples the vector current to the rho. The transition rate is calculated as γ/sub rho/ -1 = f/sub pi//m/sub rho/ in rough agreement with experiment. This picture requires soft rho's to decouple. The chiral partner of the rho is not the A 1 but the B (1235). The experimental absence of the A 1 is no longer a theoretical embarrassment in this scheme. As the analog of PCAC for the pion we establish a tensor-field identity for the rho meson in which the rho is interpreted as a dormant Goldstone state. The decays delta → eta + π, B → ω + π, epsilon → 2π are estimated and are found to be in agreement with the observed rates. A static U(6) x U(6) generalization of the Σ model is presented with the π, rho, sigma, B in the (6, 6) + (6, 6) representation. The rho emerges as a dormant Goldstone boson in this model
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}.
International Nuclear Information System (INIS)
Maris, Th.A.J.
1976-01-01
The renormalization group theory has a natural place in a general framework of symmetries in quantum field theories. Seen in this way, a 'renormalization group' is a one-parametric subset of the direct product of dilatation and renormalization groups. This subset of spontaneously broken symmetry transformations connects the inequivalent solutions generated by a parameter-dependent regularization procedure, as occurs in renormalized perturbation theory. By considering the global, rather than the infinitesimal, transformations, an expression for general vertices is directly obtained, which is the formal solution of exact renormalization group equations [pt
Non-local ground-state functional for quantum spin chains with translational broken symmetry
Energy Technology Data Exchange (ETDEWEB)
Libero, Valter L.; Penteado, Poliana H.; Veiga, Rodrigo S. [Universidade de Sao Paulo (IFSC/USP), Sao Carlos, SP (Brazil). Inst. de Fisica
2011-07-01
Full text. Thanks to the development and use of new materials with special doping, it becomes relevant the study of Heisenberg spin-chains with broken translational symmetry, induced for instance by finite-size effects, bond defects or by impurity spin in the chain. The exact numerical results demands huge computational efforts, due to the size of the Hilbert space involved and the lack of symmetry to exploit. Density Functional Theory (DFT) has been considered a simple alternative to obtain ground-state properties for such systems. Usually, DFT starts with a uniform system to build the correlation energy and after implement a local approximation to construct local functionals. Based on our prove of the Hohenberg-Kohn theorem for Heisenberg models, and in order to describe more realistic models, we have recently developed a non-local exchange functional for the ground-state energy of quantum-spin chains. A alternating-bond chain is used to obtain the correlation energy and a local unit-cell approximation - LUCA, is defined in the context of DFT. The alternating chain is a good starting point to construct functionals since it is intrinsically non-homogeneous, therefore instead of the usual local approximation (like LDA for electronic systems) we need to introduce an approximation based upon a unit cell concept, that renders a non-local functional in the bond exchange interaction. The agreement with exact numerical data (obtained only for small chains, although the functional can be applied for chains with arbitrary size) is significantly better than in our previous local formulation, even for chains with several ferromagnetic or antiferromagnetic bond defects. These results encourage us to extend the concept of LUCA for chains with alternating-spin magnitudes. We also have constructed a non-local functional based on an alternating-spin chain, instead of a local alternating-bond, using spin-wave-theory. Because of its non-local nature, this functional is expected to
Non-local ground-state functional for quantum spin chains with translational broken symmetry
International Nuclear Information System (INIS)
Libero, Valter L.; Penteado, Poliana H.; Veiga, Rodrigo S.
2011-01-01
Full text. Thanks to the development and use of new materials with special doping, it becomes relevant the study of Heisenberg spin-chains with broken translational symmetry, induced for instance by finite-size effects, bond defects or by impurity spin in the chain. The exact numerical results demands huge computational efforts, due to the size of the Hilbert space involved and the lack of symmetry to exploit. Density Functional Theory (DFT) has been considered a simple alternative to obtain ground-state properties for such systems. Usually, DFT starts with a uniform system to build the correlation energy and after implement a local approximation to construct local functionals. Based on our prove of the Hohenberg-Kohn theorem for Heisenberg models, and in order to describe more realistic models, we have recently developed a non-local exchange functional for the ground-state energy of quantum-spin chains. A alternating-bond chain is used to obtain the correlation energy and a local unit-cell approximation - LUCA, is defined in the context of DFT. The alternating chain is a good starting point to construct functionals since it is intrinsically non-homogeneous, therefore instead of the usual local approximation (like LDA for electronic systems) we need to introduce an approximation based upon a unit cell concept, that renders a non-local functional in the bond exchange interaction. The agreement with exact numerical data (obtained only for small chains, although the functional can be applied for chains with arbitrary size) is significantly better than in our previous local formulation, even for chains with several ferromagnetic or antiferromagnetic bond defects. These results encourage us to extend the concept of LUCA for chains with alternating-spin magnitudes. We also have constructed a non-local functional based on an alternating-spin chain, instead of a local alternating-bond, using spin-wave-theory. Because of its non-local nature, this functional is expected to
International Nuclear Information System (INIS)
Abe, Eiji; Saitoh, Koh; Takakura, H.; Tsai, A. P.; Steinhardt, P. J.; Jeong, H.-C.
2000-01-01
We present new evidence supporting the quasi-unit-cell description of the Al 72 Ni 20 Co 8 decagonal quasicrystal which shows that the solid is composed of repeating, overlapping decagonal cluster columns with broken tenfold symmetry. We propose an atomic model which gives a significantly improved fit to electron microscopy experiments compared to a previous proposal by us and to alternative proposals with tenfold symmetric clusters. (c) 2000 The American Physical Society
Clerkin, Eoin; O'Brien, Stephen; Amann, Andreas
2014-03-01
We theoretically investigate the dynamics of two mutually coupled, identical single-mode semi-conductor lasers. For small separation and large coupling between the lasers, symmetry-broken one-color states are shown to be stable. In this case the light outputs of the lasers have significantly different intensities while at the same time the lasers are locked to a single common frequency. For intermediate coupling we observe stable symmetry-broken two-color states, where both lasers lase simultaneously at two optical frequencies which are separated by up to 150 GHz. Using a five-dimensional model, we identify the bifurcation structure which is responsible for the appearance of symmetric and symmetry-broken one-color and two-color states. Several of these states give rise to multistabilities and therefore allow for the design of all-optical memory elements on the basis of two coupled single-mode lasers. The switching performance of selected designs of optical memory elements is studied numerically.
Energy Technology Data Exchange (ETDEWEB)
Albright, Carl H.; /Northern Illinois U. /Fermilab; Rodejohann, Werner; /Heidelberg, Max Planck Inst.
2008-04-01
To address the issue of whether tri-bimaximal mixing (TBM) is a softly-broken hidden or an accidental symmetry, we adopt a model-independent analysis in which we perturb a neutrino mass matrix leading to TBM in the most general way but leave the three texture zeros of the diagonal charged lepton mass matrix unperturbed. We compare predictions for the perturbed neutrino TBM parameters with those obtained from typical SO(10) grand unified theories with a variety of flavor symmetries. Whereas SO(10) GUTs almost always predict a normal mass hierarchy for the light neutrinos, TBM has a priori no preference for neutrino masses. We find, in particular for the latter, that the value of |U{sub e3}| is very sensitive to the neutrino mass scale and ordering. Observation of |U{sub e3}|{sup 2} > 0.001 to 0.01 within the next few years would be incompatible with softly-broken TBM and a normal mass hierarchy and would suggest that the apparent TBM symmetry is an accidental symmetry instead. No such conclusions can be drawn for the inverted and quasi-degenerate hierarchy spectra.
International Nuclear Information System (INIS)
Masago, Akira; Suzuki, Naoshi
2001-01-01
By a group theoretical procedure we derive the possible spontaneously broken-symmetry states for the two-fold degenerate Hubbard model on a two-dimensional triangular lattice. For ordering wave vectors corresponding to the points Γ and K in the first BZ we find 22 states which include 16 collinear and six non-collinear states. The collinear states include the usual SDW and CDW states which appear also in the single-band Hubbard model. The non-collinear states include exotic ordering states of orbitals and spins as well as the triangular arrangement of spins
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...
International Nuclear Information System (INIS)
Veryaskin, A.V.; Lapchinskij, V.G.; Nekrasov, V.I.; Rubakov, V.A.
1981-01-01
Behaviour of vacuum symmetry in the model of self-acting scalar field in the open and closed isotropic cosmological spaces is investigated. Considered are the cases with the mass squared of the scalar field m 2 >0, m 2 =0 and m 2 2 2 =0 at exponentially large scale factors the study of the problem on the behaviour of the symmetry requires exceeding the limits of the perturbation theory. The final behaviour of the vacuum symmetry in the open model at small radii depends on combined effect of all the external factors [ru
Lattice QCD with light quark masses: Does chiral symmetry get broken spontaneously
International Nuclear Information System (INIS)
Barbour, I.M.; Schierholz, G.; Teper, M.; Gilchrist, J.P.; Schneider, H.
1983-03-01
We present a first direct calculation of the properties of QCD for the small quark masses of phenomenological interest without extrapolations. We describe methods specially adapted to invert the fermion matrix at small quark masses. We use these methods to calculate directly on presently used lattice sizes with different boundary conditions. As is to be expected for a finite system, we do not observe spontaneous chiral symmetry breaking. By comparing the results obtained on lattices of different size we see, however, indications that are consistent with eventual spontaneous chiral symmetry breaking in the infinite volume limit. Our calculations underline the importance of using antiperiodic boundary conditions for fermions. (orig.)
Broken SU(5) x SU(5) chiral symmetry and the classification of B mesons
International Nuclear Information System (INIS)
Hatzis, M.
1984-01-01
We consider broken SU(5) x SU(5) chiral summetry and we assume that the vacuum is SU(5)-symmetric. Using the observed mass spectrum of pseudoscalar mesons, and setting the bu mass in the range 5.2 +- 0.06 GeV, we predict the masses of bs, bc, and etasub(b) states as well as axial current couplings fsub(i)/fsub(π). SU(5) x SU(5) is found to be consistent with SU(4) x SU(4) breaking. The problem of eta - eta' - eta sub(c) - eta sub(b) mixing is also discussed
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 ...
Influence of broken flavor and C and P symmetry on the quark propagator
Energy Technology Data Exchange (ETDEWEB)
Maas, Axel; Mian, Walid Ahmed [University of Graz, Institute of Physics, NAWI Graz, Graz (Austria)
2017-02-15
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. (orig.)
Broken symmetries at the origin of matter, at the origin of life and at the origin of culture
International Nuclear Information System (INIS)
Klinken, J. van
1998-01-01
In earliest cosmic history the universe started with matter and not with antimatter. Shortly after the beginning the electroweak interaction - prominent in nuclear β decay - acted as a left-hander. Much later, in pre biotic evolution, optically left-handed amino acids determined the unique signature of following terrestrial organic life. Again ae- ons later, homo sapiens appears as predominantly right handed and creates cultures with many broken symmetries. Along these pathways of history it was essential that choices were made - left or right, matter or antimatter - but on several instances it seemed less relevant which choice were made. We think that biochirality occurred by global chance; perhaps by local necessity, but without causal links to the PCT theorem. In other cases - e.g. the standardization to right-handed screws - the choice will have been made by causal necessity. (author)
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.
Broken symmetries at the origin of matter, at the origin of life and at the origin of culture
Energy Technology Data Exchange (ETDEWEB)
Klinken, J. van [Kernfysisch Versneller Instituut, University of Groningen, Groningen (Netherlands)
1998-01-01
In earliest cosmic history the universe started with matter and not with antimatter. Shortly after the beginning the electroweak interaction - prominent in nuclear {beta} decay - acted as a left-hander. Much later, in pre biotic evolution, optically left-handed amino acids determined the unique signature of following terrestrial organic life. Again ae- ons later, homo sapiens appears as predominantly right handed and creates cultures with many broken symmetries. Along these pathways of history it was essential that choices were made - left or right, matter or antimatter - but on several instances it seemed less relevant which choice were made. We think that biochirality occurred by global chance; perhaps by local necessity, but without causal links to the PCT theorem. In other cases - e.g. the standardization to right-handed screws - the choice will have been made by causal necessity. (author) 14 refs, 8 figs, 1 tab
International Nuclear Information System (INIS)
Shaing, K.C.; Hsu, C.T.
2014-01-01
A transport theory for energetic fusion born alpha particles in tokamaks with broken symmetry has been developed. The theory is a generalization of the theory for neoclassical toroidal plasma viscosity for thermal particles in tokamaks. It is shown that the radial energy transport rate can be comparable to the slowing down rate for energetic alpha particles when the ratio of the typical magnitude of the perturbed magnetic field strength to that of the equilibrium magnetic field strength is of the order of 10 −4 or larger. This imposes a constraint on the magnitude of the error fields in thermonuclear fusion reactors. The implications on stellarators as potential fusion reactors are also discussed. (paper)
Broken symmetry within crystallographic super-spaces: structural and dynamical aspects
International Nuclear Information System (INIS)
Mariette, Celine
2013-01-01
Aperiodic crystals have the property to possess long range order without translational symmetry. These crystals are described within the formalism of super-space crystallography. In this manuscript, we will focus on symmetry breaking which take place in such crystallographic super-space groups, considering the prototype family of n-alkane/urea. Studies performed by X-ray diffraction using synchrotron sources reveal multiple structural solutions implying or not changes of the dimension of the super-space. Once the characterization of the order parameter and of the symmetry breaking is done, we present the critical pre-transitional phenomena associated to phase transitions of group/subgroup types. Coherent neutron scattering and inelastic X-ray scattering allow a dynamical analysis of different kind of excitations in these materials (phonons, phasons). The inclusion compounds with short guest molecules (alkane C n H 2n+2 , n varying from 7 to 13) show at room temperature unidimensional 'liquid-like' phases. The dynamical disorder along the incommensurate direction of these materials generates new structural solutions at low temperature (inter-modulated monoclinic composite, commensurate lock-in). (author) [fr
Lu, Jin-Cheng; Chen, Xiao-Dong; Deng, Wei-Min; Chen, Min; Dong, Jian-Wen
2018-07-01
The valley is a flexible degree of freedom for light manipulation in photonic systems. In this work, we introduce the valley concept in magnetic photonic crystals with broken inversion symmetry. One-way propagation of bulk states is demonstrated by exploiting the pseudo-gap where bulk states only exist at one single valley. In addition, the transition between Hall and valley-Hall nontrivial topological phases is also studied in terms of the competition between the broken inversion and time-reversal symmetries. At the photonic boundary between two topologically distinct photonic crystals, we illustrate the one-way propagation of edge states and demonstrate their robustness against defects.
Directory of Open Access Journals (Sweden)
Yaser Hajati
2015-04-01
Full Text Available We investigate the charge transport through a graphene-based ferromagnetic-insulator-superconductor junction with a broken time reversal symmetry (BTRS of dx2−y2 + is and dx2−y2 + idxy superconductor using the extended Blonder-Tinkham-Klapwijk formalism. Our analysis have shown several charateristics in this junction, providing a useful probe to understand the role of the order parameter symmetry in the superconductivity. We find that the presence of the BTRS (X state in the superconductor region has a strong effect on the tunneling conductance curves which leads to a decrease in the height of the zero-bias conductance peak (ZBCP. In particular, we show that the magnitude of the superconducting proximity effect depends to a great extent on X and by increasing X, the zero-bias charge conductance oscillations with respect to the rotation angle β are suppressed. In addition, we find that at the maximum rotation angle β = π/4, introducing BTRS in the FIS junction causes oscillatory behavior of the zero-bias charge conductance with the barrier strength (χG by a period of π and by approaching the X to 1, the amplitude of charge conductance oscillations increases. This behavior is drastically different from none BTRS similar graphene junctions. At last, we suggest an experimental setup for verifying our predicted effects.
Marginal deformations of 3d supersymmetric U(N) model and broken higher spin symmetry
Energy Technology Data Exchange (ETDEWEB)
Hikida, Yasuaki [Center for Gravitational Physics, Yukawa Institute for Theoretical Physics, Kyoto University,Kyoto 606-8502 (Japan); Wada, Taiki [Department of Physical Sciences, College of Science and Engineering, Ritsumeikan University,Shiga 525-8577 (Japan)
2017-03-08
We examine the marginal deformations of double-trace type in 3d supersymmetric U(N) model with N complex free bosons and fermions. We compute the anomalous dimensions of higher spin currents to the 1/N order but to all orders in the deformation parameters by mainly applying the conformal perturbation theory. The 3d field theory is supposed to be dual to 4d supersymmetric Vasiliev theory, and the marginal deformations are argued to correspond to modifying boundary conditions for bulk scalars and fermions. Thus the modification should break higher spin gauge symmetry and generate the masses of higher spin fields. We provide supports for the dual interpretation by relating bulk computation in terms of Witten diagrams to boundary one in conformal perturbation theory.
Marginal deformations of 3d supersymmetric U(N) model and broken higher spin symmetry
International Nuclear Information System (INIS)
Hikida, Yasuaki; Wada, Taiki
2017-01-01
We examine the marginal deformations of double-trace type in 3d supersymmetric U(N) model with N complex free bosons and fermions. We compute the anomalous dimensions of higher spin currents to the 1/N order but to all orders in the deformation parameters by mainly applying the conformal perturbation theory. The 3d field theory is supposed to be dual to 4d supersymmetric Vasiliev theory, and the marginal deformations are argued to correspond to modifying boundary conditions for bulk scalars and fermions. Thus the modification should break higher spin gauge symmetry and generate the masses of higher spin fields. We provide supports for the dual interpretation by relating bulk computation in terms of Witten diagrams to boundary one in conformal perturbation theory.
Coherent non-linear optical response in SU(2) symmetry broken single and bilayer graphene
International Nuclear Information System (INIS)
Kumar, Vipin; Enamullah,; Kumar, Upendra; Setlur, Girish S.
2014-01-01
Anomalous Rabi oscillations in single and bilayer graphene, in the absence of time-reversal symmetry, are described. The main findings of this work are that intra-layer sublattice space asymmetry has a remarkable effect on anomalous Rabi frequency in single and bilayer graphene, namely it is offset by the asymmetry parameter. However, the conventional Rabi frequency is nearly independent of the asymmetry parameter. Inter-layer asymmetry in bilayer graphene has an even more significant effect on anomalous Rabi frequency. When inter-layer asymmetry is taken into account, the anomalous Rabi frequency versus the external field goes through a minimum. The induced current in the frequency domain in these systems shows a finite threshold behavior even for vanishingly small applied fields. These offset oscillations are attributable to the asymmetry parameter in these systems, and are observable only for weak applied fields. For stronger applied fields these phenomena tend towards those without asymmetry
Turov, Evgenii A.; Shavrov, Vladimir G.
1983-07-01
This review of some aspects of the magnetoacoustics of ferro- and antiferromagnetic materials has been written in connection with the 25th anniversary of the rise of this field of physics of magnetic phenomena. Primary attention is paid to relatively new problems that have not been reflected in the existing monographs and reviews. The topic is a group of linear magnetoacoustic effects that manifest spontaneous symmetry breaking caused by magnetic ordering in a system of two coupled fields: the magnetization field M (r) and the deformation field uij(r). To some extent these effects are analogous to the Higgs effect in the theory of elementary particles (the Higgs mechanism of the origin of the mass of a particle) or the Meissner effect in the theory of superconductivity. A direct analog of the stated effects is the so-called magnetoelastic gap in the magnon spectrum, while an analog of an accompanying effect is the softening of the quasiacoustic modes interacting with it (up to the vanishing of the corresponding dynamic elastic moduli). However, a characteristic feature of such effects in crystalline (anisotropic) magnetic materials is that they are manifested mainly near points of magnetic (spin-reorientation) phase transitions. This review treats the coupled magnetoelastic waves in ferro- and antiferromagnetic materials of different types that show phase transitions with respect to temperature, magnetic field, or pressure.
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.
Chubb, Scott
2003-03-01
Three, Key, Unanswered Questions posed by LENR's are: 1. How do we explain the lack of high energy particles (HEP's)? 2. Can we understand and prioritize the way coupling can occur between nuclear- and atomic- lengthscales, and 3. What are the roles of Surface-Like (SL), as opposed to Bulk-Like (BL), processes in triggering nuclear phenomena. One important source of confusion associated with each of these questions is the common perception that the quantum mechanical phases of different particles are not correlated with each other. When the momenta p of interacting particles is large, and reactions occur rapidly (between HEP's, for example), this is a valid assumption. But when the relative difference in p becomes vanishingly small, between one charge, and many others, as a result of implicit electromagnetic coupling, each charge can share a common phase, relative to the others, modulo 2nπ, where n is an integer, even when outside forces are introduced. The associated forms of broken gauge symmetry, distinguish BL from SL phenomena, at room temperature, also explain super- and normal- conductivity in solids, and can be used to address the Three, Key, Unanswered Questions posed by LENR's.
International Nuclear Information System (INIS)
Strinati, G.C.; Pieri, P.
2004-01-01
The linear response to a space- and time-dependent external disturbance of a system of dilute condensed composite bosons at zero temperature, as obtained from the linearized version of the time-dependent Gross-Pitaevskii equation, is shown to result also from the strong-coupling limit of the time-dependent BCS (or broken-symmetry random-phase) approximation for the constituent fermions subject to the same external disturbance. In this way, it is possible to connect excited-state properties of the bosonic and fermionic systems by placing the Gross-Pitaevskii equation in perspective with the corresponding fermionic approximations
International Nuclear Information System (INIS)
Lazzaro, Enzo
2009-01-01
Established results of neoclassical kinetic theory are used in a fluid model to show that in low collisionality regimes (ν and 1/ν) the propagation velocity of Neoclassical Tearing Modes (NTM) magnetic islands of sufficient width is determined self-consistently by the Neoclassical Toroidal Viscosity (NTV) appearing because of broken symmetry. The NTV effect on bulk plasma rotation, may also explain recent observations on momentum transport. At the same time this affects the role of the neoclassical ion polarization current on neoclassical tearing modes (NTM) stability.
Energy Technology Data Exchange (ETDEWEB)
Grinstein, Benjamín [Department of Physics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093 (United States); Murphy, Christopher W. [Scuola Normale Superiore, Piazza dei Cavalieri 7, Pisa 56126 (Italy); Uttayarat, Patipan [Department of Physics, Srinakharinwirot University, Wattana, Bangkok 10110 (Thailand)
2016-06-13
We compute all of the one-loop corrections that are enhanced, O(λ{sub i}λ{sub j}/16π{sup 2}), in the limit s≫|λ{sub i}|v{sup 2}≫M{sub W}{sup 2}, s≫m{sub 12}{sup 2} to all the 2→2 longitudinal vector boson and Higgs boson scattering amplitudes in the CP-conserving two-Higgs doublet model with a softly broken ℤ{sub 2} symmetry. In the two simplified scenarios we study, the typical bound we find is |λ{sub i}(s)|⪅4.
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...... is employed to explain the effect. We consider a case of a particle in a periodic potential as an example and discuss the relevant symmetry breakings and the mechanisms of rectification of the current in such a system.......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...
International Nuclear Information System (INIS)
Becker, R.L.; Svenne, J.P.
1975-12-01
Energy levels of states connected by a symmetry of the Hamiltonian normally should be degenerate. In self-consistent field theories, when only one of a pair of single-particle levels connected by a symmetry of the full Hamiltonian is occupied, the degeneracy is split and the unoccupied level often lies below the occupied one. Inversions of neutron-proton (charge) and time-reversal doublets in odd nuclei, charge doublets in even nuclei with a neutron excess, and spin-orbit doublets in spherical configurations with spin-unsaturated shells are examined. The origin of the level inversion is investigated, and the following explanation offered. Unoccupied single-particle levels, from a calculation in an A-particle system, should be interpreted as levels of the (A + 1)-particle system. When the symmetry-related level, occupied in the A-particle system, is also calculated in the (A + 1)-particle system it is degenerate with or lies lower than the other. That is, when both levels are calculated in the (A + 1)-particle system, they are not inverted. It is demonstrated that the usual prescription to occupy the lowest-lying orbitals should be modified to refer to the single-particle energies calculated in the (A + 1)- or the (A - 1)-particle system. This observation is shown to provide a justification for avoiding an oscillation of occupancy between symmetry-related partners in successive iterations leading to a self-consistency. It is pointed out that two degenerate determinants arise from occupying one or the other partner of an initially degenerate pair of levels and then iterating to self-consistency. The existence of the degenerate determinants indicates the need for introducing correlations, either by mixing the two configurations or by allowing additional symmetry-breaking (resulting in a more highly deformed non-degenerate configuration). 2 figures, 3 tables, 43 references
International Nuclear Information System (INIS)
Hupin, G; Lacroix, D; Bender, M
2011-01-01
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.
Yu, Yang; Li, Chen; Yin, Bing; Li, Jian-Li; Huang, Yuan-He; Wen, Zhen-Yi; Jiang, Zhen-Yi
2013-08-07
The structures, relative stabilities, vertical electron detachment energies, and magnetic properties of a series of trinuclear clusters are explored via combined broken-symmetry density functional theory and ab initio study. Several exchange-correlation functionals are utilized to investigate the effects of different halogen elements and central atoms on the properties of the clusters. These clusters are shown to possess stronger superhalogen properties than previously reported dinuclear superhalogens. The calculated exchange coupling constants indicate the antiferromagnetic coupling between the transition metal ions. Spin density analysis demonstrates the importance of spin delocalization in determining the strengths of various couplings. Spin frustration is shown to occur in some of the trinuclear superhalogens. The coexistence of strong superhalogen properties and spin frustration implies the possibility of trinuclear superhalogens working as the building block of new materials of novel magnetic properties.
Broken symmetry in the mean field theory of the ising spin glass: replica way and no replica way
International Nuclear Information System (INIS)
De Dominicis, C.
1983-06-01
We review the type of symmetry breaking involved in the solution discovered by Parisi and in the static derivation of the solution first introduced via dynamics by Sompolinsky. We turn to a formulation of the problem due to Thouless, Anderson and Palmer (TAP) that put a set of equations for the magnetization. A probability law for the magnetization is then built. We consider two cases: (i) a canonical distribution which is shown to give indentical results to the Hamiltonian formulation under a weak and physical assumption and (ii) a white distribution characterized by two matrices and a response. We show what symmetry breaking is necessary to recover Sompolinsky free energy. In section III we supplement replica indices in the Hamiltonian approach by ''time'' indices ans show in particular that the analytic continuation involved in Sompolinsky's equilibrium derivation, is trying to mimick a translational symmetry breaking in ''time'' that incorporates Sompolinsky's ansatz of a long time scale sequence. In section IV we apply the same treatment to the white average approach and show that, replicas can be altogether discorded and replaced by ''time''. Finally, we briefly discuss the attribution of distinct answers for the standard spin glass order parameter depending on the physical situation: equilibrium or non equilibrium associated with canonical or white (non canonical) initial conditions and density matrices
International Nuclear Information System (INIS)
Becker, D.; Reuter, M.
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. Carefully disentangling fluctuation and background fields, we employ a ‘bi-metric’ ansatz for the EAA and project the flow generated by its functional renormalization group equation on a truncated theory space spanned by two separate Einstein–Hilbert actions for the dynamical and the background metric, respectively. A new powerful method is used to derive the corresponding renormalization group (RG) equations for the Newton- and cosmological constant, both in the dynamical and the background sector. We classify and analyze their solutions in detail, determine their fixed point structure, and identify an attractor mechanism which turns out instrumental in the split-symmetry restoration. We show that there exists a subset of RG trajectories which are both asymptotically safe and split-symmetry restoring: In the ultraviolet they emanate from a non-Gaussian fixed point, and in the infrared they loose all symmetry violating contributions inflicted on them by the
International Nuclear Information System (INIS)
Solin, J.
1988-01-01
The one-loop renormalization of the λφ 4 theory with a spontaneous breaking of its discrete (reflection) symmetry is analyzed. It is explicitly shown that it is not necessary to forcefully eliminate the linear counterterm in the shifted field (accomplished usually by shifting the vacuum expectation value of the field) in order to have the renormalized Lagrangian still formally invariant under the original discrete symmetry. It is further shown, using the normal-ordering procedure, that the renormalization carried out in the customary form completely wipes out the tadpole diagram contributions from the original Lagrangian. As a consequence, the same renormalized Lagrangian can be also obtained from the original bare Lagrangian which, however, has been normal-ordered and as such cannot cause the linear counterterm in the shifted field since now the tadpole diagrams are absent altogether. These analyses should support the view that the vacuum expectation value of the field is of a group-theoretical origin rather than a field-theoretical origin, and as such should not change independently of the shifted field in the course of renormalization
Grosse, E.; Junghans, A. R.; Wilson, J. N.
2017-11-01
The basic parameters for calculations of radiative neutron capture, photon strength functions and nuclear level densities near the neutron separation energy are determined based on experimental data without an ad hoc assumption about axial symmetry—at variance to previous analysis. Surprisingly few global fit parameters are needed in addition to information on nuclear deformation, taken from Hartree Fock Bogolyubov calculations with the Gogny force, and the generator coordinator method assures properly defined angular momentum. For a large number of nuclei the GDR shapes and the photon strength are described by the sum of three Lorentzians, extrapolated to low energies and normalised in accordance to the dipole sum rule. Level densities are influenced strongly by the significant collective enhancement based on the breaking of shape symmetry. The replacement of axial symmetry by the less stringent requirement of invariance against rotation by 180° leads to a novel prediction for radiative neutron capture. It compares well to recent compilations of average radiative widths and Maxwellian average cross sections for neutron capture by even target nuclei. An extension to higher spin promises a reliable prediction for various compound nuclear reactions also outside the valley of stability. Such predictions are of high importance for future nuclear energy systems and waste transmutation as well as for the understanding of the cosmic synthesis of heavy elements.
Liu, Yinan; Gu, Qiangqiang; Peng, Yu; Qi, Shaomian; Zhang, Na; Zhang, Yinong; Ma, Xiumei; Zhu, Rui; Tong, Lianming; Feng, Ji; Liu, Zheng; Chen, Jian-Hao
2018-05-07
The layered ternary compound TaIrTe 4 is an important candidate to host the recently predicted type-II Weyl fermions. However, a direct and definitive proof of the absence of inversion symmetry in this material, a prerequisite for the existence of Weyl Fermions, has so far remained evasive. Herein, an unambiguous identification of the broken inversion symmetry in TaIrTe 4 is established using angle-resolved polarized Raman spectroscopy. Combining with high-resolution transmission electron microscopy, an efficient and nondestructive recipe to determine the exact crystallographic orientation of TaIrTe 4 crystals is demonstrated. Such technique could be extended to the fast identification and characterization of other type-II Weyl fermions candidates. A surprisingly strong in-plane electrical anisotropy in TaIrTe 4 thin flakes is also revealed, up to 200% at 10 K, which is the strongest known electrical anisotropy for materials with comparable carrier density, notably in such good metals as copper and silver. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
International Nuclear Information System (INIS)
Adler, S.L.
1999-01-01
We construct extensions of the standard model based on the hypothesis that Higgs bosons also exhibit a family structure and that the flavor weak eigenstates in the three families are distinguished by a discrete Z 6 chiral symmetry that is spontaneously broken by the Higgs sector. We study in detail at the tree level models with three Higgs doublets and with six Higgs doublets comprising two weakly coupled sets of three. In a leading approximation of S 3 cyclic permutation symmetry the three-Higgs-doublet model gives a open-quotes democraticclose quotes mass matrix of rank 1, while the six-Higgs-doublet model gives either a rank-1 mass matrix or, in the case when it spontaneously violates CP, a rank-2 mass matrix corresponding to nonzero second family masses. In both models, the CKM matrix is exactly unity in the leading approximation. Allowing small explicit violations of cyclic permutation symmetry generates small first family masses in the six-Higgs-doublet model, and first and second family masses in the three-Higgs-doublet model, and gives a nontrivial CKM matrix in which the mixings of the first and second family quarks are naturally larger than mixings involving the third family. Complete numerical fits are given for both models, flavor-changing neutral current constraints are discussed in detail, and the issues of unification of couplings and neutrino masses are addressed. On a technical level, our analysis uses the theory of circulant and retrocirculant matrices, the relevant parts of which are reviewed. copyright 1998 The American Physical Society
International Nuclear Information System (INIS)
Shirkov, Dmitrii V
2009-01-01
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. (oral issue of the journal 'uspekhi fizicheskikh nauk')
Spin-flip dynamics of the Curie-Weiss model Loss of Gibbsianness with possibly broken symmetry.
Külske, C
2005-01-01
We study the conditional probabilities of the Curie-Weiss Ising model in vanishing external field under a symmetric independent stochastic spin-flip dynamics and discuss their set of bad configurations (points of discontinuity). We exhibit a complete analysis of the transition between Gibbsian and non-Gibbsian behavior as a function of time, extending the results for the corresponding lattice model, where only partial answers can be obtained. For initial inverse temperature $\\b \\leq 1$, we prove that the time-evolved measure is always Gibbsian. For $1 \\frac{3}{2}$, we observe the new phenomenon of symmetry-breaking of bad configurations: The time-evolved measure loses its Gibbsian character at a sharp transition time, and bad configurations with non-zero spin-average appear. These bad configurations merge into a neutral configuration at a later transition time, while the measure stays non-Gibbs. In our proof we give a detailed analysis of the phase-diagram of a Curie-Weiss random field Ising model with possi...
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.
... Drugs & Supplements Videos & Tools Español You Are Here: Home → Medical Encyclopedia → Broken bone URL of this page: //medlineplus.gov/ency/ ... following steps to reduce your risk of a broken bone: Wear protective ... pads. Create a safe home for young children. Place a gate at stairways ...
... of falling — including football, soccer, gymnastics, skiing and skateboarding — also increases the risk of a broken arm. ... for high-risk activities, such as in-line skating, snowboarding, rugby and football. Don't smoke. Smoking ...
International Nuclear Information System (INIS)
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
International Nuclear Information System (INIS)
Endlich, Solomon; Nicolis, Alberto; Penco, Riccardo
2015-01-01
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 Poincaré 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.
Liang, Hong-Qin; Liu, Bin; Hu, Jin-Feng; He, Xing-Dao
2018-05-01
An all-optical plasmonic diode, comprising a metal-insulator-metal waveguide coupled with a stub cavity, is proposed based on a nonlinear Fano structure. The key technique used is to break structural spatial symmetry by a simple reflector layer in the waveguide. The spatial asymmetry of the structure gives rise to the nonreciprocity of coupling efficiencies between the Fano cavity and waveguides on both sides of the reflector layer, leading to a nonreciprocal nonlinear response. Transmission properties and dynamic responses are numerically simulated and investigated by the nonlinear finite-difference time-domain method. In the proposed structure, high-efficiency nonreciprocal transmission can be achieved with a low power threshold and an ultrafast response time (subpicosecond level). A high maximum transmittance of 89.3% and an ultra-high transmission contrast ratio of 99.6% can also be obtained. The device can be flexibly adjusted for working wavebands by altering the stub cavity length.
Janesko, Benjamin G.
2018-02-01
Parameter-free atomistic simulations of entangled solid-state paramagnetic defects may aid in the rational design of devices for quantum information science. This work applies time-dependent density functional theory (TDDFT) embedded-cluster simulations to a prototype entangled-defect system, namely two adjacent singlet-coupled F color centers in lithium fluoride. TDDFT calculations accurately reproduce the experimental visible absorption of both isolated and coupled F centers. The most accurate results are obtained by combining spin symmetry breaking to simulate strong correlation, a large fraction of exact (Hartree-Fock-like) exchange to minimize the defect electrons' self-interaction error, and a standard semilocal approximation for dynamical correlations between the defect electrons and the surrounding ionic lattice. These results motivate application of two-reference correlated ab initio approximations to the M-center, and application of TDDFT in parameter-free simulations of more complex entangled paramagnetic defect architectures.
Kemeth, Felix P.; Haugland, Sindre W.; Krischer, Katharina
2018-05-01
Symmetry broken states arise naturally in oscillatory networks. In this Letter, we investigate chaotic attractors in an ensemble of four mean-coupled Stuart-Landau oscillators with two oscillators being synchronized. We report that these states with partially broken symmetry, so-called chimera states, have different setwise symmetries in the incoherent oscillators, and in particular, some are and some are not invariant under a permutation symmetry on average. This allows for a classification of different chimera states in small networks. We conclude our report with a discussion of related states in spatially extended systems, which seem to inherit the symmetry properties of their counterparts in small networks.
Spontaneously broken abelian gauge invariant supersymmetric model
International Nuclear Information System (INIS)
Mainland, G.B.; Tanaka, K.
A model is presented that is invariant under an Abelian gauge transformation and a modified supersymmetry transformation. This model is broken spontaneously, and the interplay between symmetry breaking, Goldstone particles, and mass breaking is studied. In the present model, spontaneously breaking the Abelian symmetry of the vacuum restores the invariance of the vacuum under a modified supersymmetry transformation. (U.S.)
Samardak, Alexander; Kolesnikov, Alexander; Stebliy, Maksim; Chebotkevich, Ludmila; Sadovnikov, Alexandr; Nikitov, Sergei; Talapatra, Abhishek; Mohanty, Jyoti; Ognev, Alexey
2018-05-01
An enhancement of the spin-orbit effects arising on an interface between a ferromagnet (FM) and a heavy metal (HM) is possible through the strong breaking of the structural inversion symmetry in the layered films. Here, we show that an introduction of an ultrathin W interlayer between Co and Ru in Ru/Co/Ru films enables to preserve perpendicular magnetic anisotropy (PMA) and simultaneously induce a large interfacial Dzyaloshinskii-Moriya interaction (iDMI). The study of the spin-wave propagation in the Damon-Eshbach geometry by Brillouin light scattering spectroscopy reveals the drastic increase in the iDMI value with the increase in W thickness (tW). The maximum iDMI of -3.1 erg/cm2 is observed for tW = 0.24 nm, which is 10 times larger than for the quasi-symmetrical Ru/Co/Ru films. We demonstrate the evidence of the spontaneous field-driven nucleation of isolated skyrmions supported by micromagnetic simulations. Magnetic force microscopy measurements reveal the existence of sub-100-nm skyrmions in the zero magnetic field. The ability to simultaneously control the strength of PMA and iDMI in quasi-symmetrical HM/FM/HM trilayer systems through the interface engineered inversion asymmetry at the nanoscale excites new fundamental and practical interest in ultrathin ferromagnets, which are a potential host for stable magnetic skyrmions.
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.
International Nuclear Information System (INIS)
Weinberg, S.
1976-01-01
The problem of how gauge symmetries of the weak interactions get broken is discussed. Some reasons why such a heirarchy of gauge symmetry breaking is needed, the reason gauge heirarchies do not seem to arise in theories of a given and related type, and the implications of theories with dynamical symmetry breaking, which can exhibit a gauge hierarchy
Greschner, S.; Piraud, M.; Heidrich-Meisner, F.; McCulloch, I. P.; Schollwöck, U.; Vekua, T.
2016-12-01
We study the quantum phases of bosons with repulsive contact interactions on a two-leg ladder in the presence of a uniform Abelian gauge field. The model realizes many interesting states, including Meissner phases, vortex fluids, vortex lattices, charge density waves, and the biased-ladder phase. Our work focuses on the subset of these states that breaks a discrete symmetry. We use density matrix renormalization group simulations to demonstrate the existence of three vortex-lattice states at different vortex densities and we characterize the phase transitions from these phases into neighboring states. Furthermore, we provide an intuitive explanation of the chiral-current reversal effect that is tied to some of these vortex lattices. We also study a charge-density-wave state that exists at 1/4 particle filling at large interaction strengths and flux values close to half a flux quantum. By changing the system parameters, this state can transition into a completely gapped vortex-lattice Mott-insulating state. We elucidate the stability of these phases against nearest-neighbor interactions on the rungs of the ladder relevant for experimental realizations with a synthetic lattice dimension. A charge-density-wave state at 1/3 particle filling can be stabilized for flux values close to half a flux quantum and for very strong on-site interactions in the presence of strong repulsion on the rungs. Finally, we analytically describe the emergence of these phases in the low-density regime, and, in particular, we obtain the boundaries of the biased-ladder phase, i.e., the phase that features a density imbalance between the legs. We make contact with recent quantum-gas experiments that realized related models and discuss signatures of these quantum states in experimentally accessible observables.
... Safe Videos for Educators Search English Español Broken Bones KidsHealth / For Parents / Broken Bones What's in this ... bone fragments in place. When Will a Broken Bone Heal? Fractures heal at different rates, depending upon ...
Some General Thoughts about Broken Symmetry.
1981-01-21
Higgs boson excitations, the long-range elastic-like forces (such as Suhl-Nakamura interactions in magnets) but most important of all the property I call...parameter is also a constant of the motion, which has important consequences for the nature of the relevant Goldstone bosons . It is too bad that in
... Safe Videos for Educators Search English Español Broken Bones KidsHealth / For Kids / Broken Bones What's in this ... sticking through the skin . What Happens When a Bone Breaks? It hurts to break a bone! It's ...
Sequential flavor symmetry breaking
International Nuclear Information System (INIS)
Feldmann, Thorsten; Jung, Martin; Mannel, Thomas
2009-01-01
The gauge sector of the standard model exhibits a flavor symmetry that allows for independent unitary transformations of the fermion multiplets. In the standard model the flavor symmetry is broken by the Yukawa couplings to the Higgs boson, and the resulting fermion masses and mixing angles show a pronounced hierarchy. In this work we connect the observed hierarchy to a sequence of intermediate effective theories, where the flavor symmetries are broken in a stepwise fashion by vacuum expectation values of suitably constructed spurion fields. We identify the possible scenarios in the quark sector and discuss some implications of this approach.
Sequential flavor symmetry breaking
Feldmann, Thorsten; Jung, Martin; Mannel, Thomas
2009-08-01
The gauge sector of the standard model exhibits a flavor symmetry that allows for independent unitary transformations of the fermion multiplets. In the standard model the flavor symmetry is broken by the Yukawa couplings to the Higgs boson, and the resulting fermion masses and mixing angles show a pronounced hierarchy. In this work we connect the observed hierarchy to a sequence of intermediate effective theories, where the flavor symmetries are broken in a stepwise fashion by vacuum expectation values of suitably constructed spurion fields. We identify the possible scenarios in the quark sector and discuss some implications of this approach.
Parastatistics and gauge symmetries
International Nuclear Information System (INIS)
Govorkov, A.B.
1982-01-01
A possible formulation of gauge symmetries in the Green parafield theory is analysed and the SO(3) gauge symmetry is shown to be on a distinct status. The Greenberg paraquark hypothesis turns out to be not equivalent to the hypothesis of quark colour SU(3)sub(c) symmetry. Specific features of the gauge SO(3) symmetry are discussed, and a possible scheme where it is an exact subgroup of the broken SU(3)sub(c) symmetry is proposed. The direct formulation of the gauge principle for the parafield represented by quaternions is also discussed
Broken Scale Invariance and Anomalous Dimensions
Wilson, K. G.
1970-05-01
Mack and Kastrup have proposed that broken scale invariance is a symmetry of strong interactions. There is evidence from the Thirring model and perturbation theory that the dimensions of fields defined by scale transformations will be changed by the interaction from their canonical values. We review these ideas and their consequences for strong interactions.
International Nuclear Information System (INIS)
Arima, A.
2003-01-01
(1) There are symmetries in nature, and the concept of symmetry has been used in art and architecture. The symmetry is evaluated high in the European culture. In China, the symmetry is broken in the paintings but it is valued in the architecture. In Japan, however, the symmetry has been broken everywhere. The serious and interesting question is why these differences happens? (2) In this lecture, I reviewed from the very beginning the importance of the rotational symmetry in quantum mechanics. I am sorry to be too fundamental for specialists of nuclear physics. But for people who do not use these theories, I think that you could understand the mathematical aspects of quantum mechanics and the relation between the angular momentum and the rotational symmetry. (3) To the specialists of nuclear physics, I talked about my idea as follows: dynamical treatment of collective motions in nuclei by IBM, especially the meaning of the degeneracy observed in the rotation bands top of γ vibration and β vibration, and the origin of pseudo-spin symmetry. Namely, if there is a symmetry, a degeneracy occurs. Conversely, if there is a degeneracy, there must be a symmetry. I discussed some details of the observed evidence and this correspondence is my strong belief in physics. (author)
International Nuclear Information System (INIS)
Gaiotto, Davide; Kapustin, Anton; Seiberg, Nathan; Willett, Brian
2015-01-01
A q-form global symmetry is a global symmetry for which the charged operators are of space-time dimension q; e.g. Wilson lines, surface defects, etc., and the charged excitations have q spatial dimensions; e.g. strings, membranes, etc. Many of the properties of ordinary global symmetries (q=0) apply here. They lead to Ward identities and hence to selection rules on amplitudes. Such global symmetries can be coupled to classical background fields and they can be gauged by summing over these classical fields. These generalized global symmetries can be spontaneously broken (either completely or to a subgroup). They can also have ’t Hooft anomalies, which prevent us from gauging them, but lead to ’t Hooft anomaly matching conditions. Such anomalies can also lead to anomaly inflow on various defects and exotic Symmetry Protected Topological phases. Our analysis of these symmetries gives a new unified perspective of many known phenomena and uncovers new results.
... broken or dislocated jaw requires prompt medical attention. Emergency symptoms include difficulty breathing or heavy bleeding. ... safety equipment, such as a helmet when playing football, or using ... can prevent or minimize some injuries to the face or jaw.
''Natural'' left-right symmetry
International Nuclear Information System (INIS)
Mohapatra, R.N.; Pati, J.C.
1975-01-01
It is remarked that left-right symmetry of the starting gauge interactions is retained as a ''natural'' symmetry if it is broken in no way except possibly by mass terms in the Lagrangian. The implications of this result for the unification of coupling constants and for parity nonconservation at low and high energies are stressed
Neutrino masses and family symmetry
International Nuclear Information System (INIS)
Grinstein, B.; Preskill, J.; Wise, M.B.
1985-01-01
Neutrino masses in the 100 eV-1 MeV range are permitted if there is a spontaneously broken global family symmetry that allows the heavy neutrinos to decay by Goldstone boson emission with a cosmologically acceptable lifetime. The family symmetry may be either abelian or nonabelian; we present models illustrating both possibilities. If the family symmetry is nonabelian, then the decay tau -> μ + Goldstone boson or tau -> e + Goldstone may have an observable rate. (orig.)
Broken superfluid in dense quark matter
Energy Technology Data Exchange (ETDEWEB)
Parganlija, Denis; Schmitt, Andreas [Institut fuer Theoretische Physik, Technische Universitaet Wien, 1040 Vienna (Austria); Alford, Mark [Department of Physics, Washington University St Louis, MO, 63130 (United States)
2014-07-01
Quark matter at high densities is a superfluid. Properties of the superfluid become highly non-trivial if the effects of strange-quark mass and the weak interactions are considered. These properties are relevant for a microscopic description of compact stars. We discuss the effect of a (small) explicitly symmetry-breaking term on the properties of a zero-temperature superfluid in a relativistic φ{sup 4} theory. If the U(1) symmetry is exact, chemical potential and superflow can be equivalently introduced either via (1) a background gauge field or (2) a topologically nontrivial mode. However, in the case of the explicitly broken symmetry, we demonstrate that the scenarios (1) and (2) lead to quantitatively different results for the mass of the pseudo-Goldstone mode and the critical velocity for superfluidity.
Lynn, Bryan W.; Starkman, Glenn D.
2017-09-01
The weak-scale U (1 )Y Abelian Higgs model (AHM) is the simplest spontaneous symmetry breaking (SSB) gauge theory: a scalar ϕ =1/√{2 }(H +i π )≡1/√{2 }H ˜ei π ˜/⟨H ⟩ and a vector Aμ. The extended AHM (E-AHM) adds certain heavy (MΦ2,Mψ2˜MHeavy2≫⟨H ⟩2˜mWeak2 ) spin S =0 scalars Φ and S =1/2 fermions ψ . In Lorenz gauge, ∂μAμ=0 , the SSB AHM (and E-AHM) has a global U (1 )Y conserved physical current, but no conserved charge. As shown by T. W. B. Kibble, the Goldstone theorem applies, so π ˜ is a massless derivatively coupled Nambu-Goldstone boson (NGB). Proof of all-loop-orders renormalizability and unitarity for the SSB case is tricky because the Becchi-Rouet-Stora-Tyutin (BRST)-invariant Lagrangian is not U (1 )Y symmetric. Nevertheless, Slavnov-Taylor identities guarantee that on-shell T-matrix elements of physical states Aμ,ϕ , Φ , ψ (but not ghosts ω , η ¯ ) are independent of anomaly-free local U (1 )Y gauge transformations. We observe here that they are therefore also independent of the usual anomaly-free U (1 )Y global/rigid transformations. It follows that the associated global current, which is classically conserved only up to gauge-fixing terms, is exactly conserved for amplitudes of physical states in the AHM and E-AHM. We identify corresponding "undeformed" [i.e. with full global U (1 )Y symmetry] Ward-Takahashi identities (WTI). The proof of renormalizability and unitarity, which relies on BRST invariance, is undisturbed. In Lorenz gauge, two towers of "1-soft-pion" SSB global WTI govern the ϕ -sector, and represent a new global U (1 )Y⊗BRST symmetry not of the Lagrangian but of the physics. The first gives relations among off-shell Green's functions, yielding powerful constraints on the all-loop-orders ϕ -sector SSB E-AHM low-energy effective Lagrangian and an additional global shift symmetry for the NGB: π ˜→π ˜+⟨H ⟩θ . A second tower, governing on-shell T-matrix elements, replaces the old Adler
Fractures (Broken Bones): First Aid
First aid Fractures (broken bones) Fractures (broken bones): First aid By Mayo Clinic Staff A fracture is a ... 10, 2018 Original article: http://www.mayoclinic.org/first-aid/first-aid-fractures/basics/ART-20056641 . Mayo Clinic ...
Mass splittings within composite Goldstone supermultiplets from broken supersymmetry
International Nuclear Information System (INIS)
Clark, T.E.; Love, S.T.
1985-01-01
The supersymmetric (SUSY) Dashen formulas are modified to include effects of softly broken supersymmetry and are used to compute the mass splittings and differences in decay constants among the various components of a Goldstone supermultiplet. The general results are applied to chiral-symmetry breaking in two-flavor SUSY QCD
Topics in broken supersymmetry
International Nuclear Information System (INIS)
Lee, I.H.
1984-01-01
Studies on two topics in the framework of broken supersymmetry are presented. Chapter I is a brief introduction in which the motivation and the background of this work are discussed. In Chapter II, the author studies the decay K + → π + γγ in models with spontaneous supersymmetry breaking and find that it is generally suppressed relative to the decay K + → π + anti nu nu of the conventional model, except possibly for a class of models where the scalar quark masses are generated by radiative corrections from a much larger supersymmetry breaking scale. For a small range of scalar quark and photino mass parameters, the cascade decay process K + → π + π 0 → π + γγ will become dominant over the anti nu nu mode. The author also comments on the possibility of probing the neutrino mass through the K + → π + π 0 → π + anti nu nu cascade decay. Chapter III is concerned with the implications of explicit lepton number violating soft operators in a general low energy effective theory with softly broken supersymmetry
Spontaneously broken realization of supersymmetry in supergravity
International Nuclear Information System (INIS)
Ferrara, S.; Trieste Univ.
1979-01-01
It is shown that if supersymmetry is relevant for the physical world it must be broken either spontaneously or explicitly. Renormalizability and simplicity are in favor of a spontaneous realization of the symmetry breaking. When supersymmetry is spontaneously broken the spinorial analogue of the Goldstone phenomenon occurs, namely massless particles arise in the spectrum of the theory which carry the same quantum numbers of the broken generators Qsup(i) they are N spin 1/2 Goldstone fermions (goldstinos). These particles may be eaten by spin 3/2 gauge particles (gravitinos) when supersymmetry is gauged. It is shown that both the Higgs effect and super Higgs effect have taken place. 8 of the spin 1/2 particles have been eaten by the spin 3/2 particles and 24 of 70 scalars have been eaten by the spin 3/2 particles and 24 of 70 scalars have been eaten by 24 of the 28 vector particles to provide them with mass. The conclusion is that the number of mass relations is, in general, equal to r-1, where r is the rank of the algebra which generates the spectrum
Symmetry and symmetry breaking
International Nuclear Information System (INIS)
Balian, R.; Lambert, D.; Brack, A.; Lachieze-Rey, M.; Emery, E.; Cohen-Tannoudji, G.; Sacquin, Y.
1999-01-01
The symmetry concept is a powerful tool for our understanding of the world. It allows a reduction of the volume of information needed to apprehend a subject thoroughly. Moreover this concept does not belong to a particular field, it is involved in the exact sciences but also in artistic matters. Living beings are characterized by a particular asymmetry: the chiral asymmetry. Although this asymmetry is visible in whole organisms, it seems it comes from some molecules that life always produce in one chirality. The weak interaction presents also the chiral asymmetry. The mass of particles comes from the breaking of a fundamental symmetry and the void could be defined as the medium showing as many symmetries as possible. The texts put together in this book show to a great extent how symmetry goes far beyond purely geometrical considerations. Different aspects of symmetry ideas are considered in the following fields: the states of matter, mathematics, biology, the laws of Nature, quantum physics, the universe, and the art of music. (A.C.)
Effective lagrangian description on discrete gauge symmetries
International Nuclear Information System (INIS)
Banks, T.
1989-01-01
We exhibit a simple low-energy lagrangian which describes a system with a discrete remnant of a spontaneously broken continuous gauge symmetry. The lagrangian gives a simple description of the effects ascribed to such systems by Krauss and Wilczek: black holes carry discrete hair and interact with cosmic strings, and wormholes cannot lead to violation of discrete gauge symmetries. (orig.)
Pauli-Guersey symmetry in gauge theories
International Nuclear Information System (INIS)
Stern, J.
1983-05-01
Gauge theories with massless or massive fermions in a selfcontragredient representation exhibit global symmetries of Pauli-Guersey type. Some of them are broken spontaneously leading to a difermion Goldstone bosons. An example of a boson version of the Pauli-Guersey symmetry is provided by the Weinberg-Salam model in the limit THETAsub(w)→O
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.)
International Nuclear Information System (INIS)
Blum, Alexander Simon
2009-01-01
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 4 , the other describing quarks and employing the symmetry D 14 . In the latter model it is the quark mixing matrix element V 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.
Axions from chiral family symmetry
International Nuclear Information System (INIS)
Chang, D.; Pal, P.B.; Maryland Univ., College Park; Senjanovic, G.
1985-01-01
We investigate the possibility that family symmetry, Gsub(F), is spontaneously broken chiral global symmetry. We classify the interesting cases when family symmetry can result in an automatic Peccei-Quinn symmetry U(1)sub(PQ) and thus provide a solution to the strong CP problem. The result disfavors having two or four families. For more than four families, U(1)sub(PQ) is in general automatic. In the case of three families, a unique Higgs sector allows U(1)sub(PQ) in the simplest case of Gsub(F)=[SU(3)] 3 . Cosmological consideration also puts strong constraint on the number of families. For Gsub(F)=[SU(N)] 3 cosmology singles out the three-family (N=3) case as a unique solution if there are three light neutrinos. Possible implication of decoupling theorem as applied to family symmetry breaking is also discussed. (orig.)
Large leptonic Dirac CP phase from broken democracy with random perturbations
Ge, Shao-Feng; Kusenko, Alexander; Yanagida, Tsutomu T.
2018-06-01
A large value of the leptonic Dirac CP phase can arise from broken democracy, where the mass matrices are democratic up to small random perturbations. Such perturbations are a natural consequence of broken residual S3 symmetries that dictate the democratic mass matrices at leading order. With random perturbations, the leptonic Dirac CP phase has a higher probability to attain a value around ± π / 2. Comparing with the anarchy model, broken democracy can benefit from residual S3 symmetries, and it can produce much better, realistic predictions for the mass hierarchy, mixing angles, and Dirac CP phase in both quark and lepton sectors. Our approach provides a general framework for a class of models in which a residual symmetry determines the general features at leading order, and where, in the absence of other fundamental principles, the symmetry breaking appears in the form of random perturbations.
Hausdorff dimensions for sets with broken scaling symmetry
International Nuclear Information System (INIS)
Umberger, D.K.; Mayer-Kress, G.; Jen, E.
1985-01-01
Based on Hausdorff's original approach to fractional dimensions, we study systems which are not sufficiently characterized by their ''fractal'' or scaling dimension. We construct informative examples of such sets and relate them to sets observed in the context of dynamical systems. 18 refs., 5 figs
The geometry of lie algebras and broken SO(6) symmetries
International Nuclear Information System (INIS)
Lawrence, T.R.
2001-10-01
Non-linear realisations of the groups SU(2), SO(1,4) and SO(2,4) are analysed, described by the coset spaces SU(2)/U(1), SO(1,4)/SO(1,3) and SO(2,4)/SO(1,3) x SO(1,1). The Lie algebras of certain special unitary and special orthogonal groups are studied and their projection operators are determined in order to facilitate the above analyses, in particular that of SO(2,4)/SO(l,3) x SO(1,1). The analysis consists of determining the transformation properties of the Goldstone bosons, constructing the most general possible Lagrangian for the realisations and finding the metric of the coset space. (author)
Hadrons and broken symmetries with WASA-at-COSY
Indian Academy of Sciences (India)
Physics of Hadrons and QCD Volume 75 Issue 2 August 2010 pp 225-234 ... is an internal experiment at the cooler synchrotron (COSY) in Jülich, Germany. ... Higher orders in chiral perturbation theory are probed with the → 0 decay.
Hadrons and broken symmetries with WASA- at-COSY
Indian Academy of Sciences (India)
Abstract. The WASA Detector Facility is an internal experiment at the cooler syn- .... This is an improvement of more than two orders of magnitude in the event ..... demonstrates the quality of the data for events coming from the reaction 1 GeV.
Quantum restoration of broken symmetry in one- dimensional loop ...
Indian Academy of Sciences (India)
Though quantum theory and classical theory are completely different from ... authors) that the classical property of a system and the classical limit of the ..... pactly supported function (for example, the alternate deposition of thin layers of GaAs.
Comment on bag models with spontaneously broken color symmetry
International Nuclear Information System (INIS)
Jandel, M.
1985-01-01
A recently suggested field-theoretic bag model, where gluons are confined via a Higgs mechanism, is discussed. It is found that the proposed model creates gluon boundary conditions that break global SU/sub c/(3) invariance. A modified scheme that removes this anomaly is suggested. However, some severe generic problems remain. Examples are the lack of a suppression mechanism for states with open color and the large surface energy of the bag states
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 ...
... pumping action and blood flow, go to the Health Topics How the Heart Works article.) Researchers are trying to identify the precise way in which the stress hormones affect the heart. Broken heart syndrome may result from ...
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)....
Deep inelastic scattering in spontaneously broken gauge models
International Nuclear Information System (INIS)
Goloskokov, S.V.; Mikhov, S.G.; Morozov, P.T.; Stamenov, D.B.
1975-01-01
Deep inelastic lepton hadron scattering in the simplest spontaneously broken symmetry (the Kibble model) is analyzed. A hypothesis that the invariant coupling constant of the quartic selfinteraction for large spacelike momenta tends to a finite asymptotic value without spoiling the asymptotic freedom for the invariant coupling constant of the Yang-Mills field is used. It is shown that Biorken scaling for the moments of the structure functions of the deep inelastic lepton hadron scattering is violated by powers of logarithms
Leptogenesis and residual CP symmetry
International Nuclear Information System (INIS)
Chen, Peng; Ding, Gui-Jun; King, Stephen F.
2016-01-01
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 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 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.
Energy Technology Data Exchange (ETDEWEB)
Hill, Christopher T.
2018-03-19
We review and expand upon recent work demonstrating that Weyl invariant theories can be broken "inertially," which does not depend upon a potential. This can be understood in a general way by the "current algebra" of these theories, independently of specific Lagrangians. Maintaining the exact Weyl invariance in a renormalized quantum theory can be accomplished by renormalization conditions that refer back to the VEV's of fields in the action. We illustrate the computation of a Weyl invariant Coleman-Weinberg potential that breaks a U(1) symmetry together,with scale invariance.
Broken Homes: Impact on Adolescents.
Koziey, Paul W.; Davies, Leigh
1982-01-01
Tends to support assertion that children from homes broken by separation, divorce, or death are less well-adjusted in terms of California Personality Inventory scales of self-control, socialization, femininity, and good impression, than children from intact homes. Age and sex were not found to be linked to the degree of maladjustment. (AH)
Unbroken versus broken mirror world: a tale of two vacua
International Nuclear Information System (INIS)
Foot, R.; Lew, H.; Volkas, R.R.
2000-01-01
If the Lagrangian of nature respects parity invariance then there are two distinct possibilities: either parity is unbroken by the vacuum or it is spontaneously broken. We examine the two simplest phenomenologically consistent gauge models which have unbroken and spontaneously broken parity symmetries, respectively. These two models have a Lagrangian of the same form, but a different parameter range is chosen in the Higgs potential. They both predict the existence of dark matter and can explain the MACHO events. However, the models predict quite different neutrino physics. Although both have light mirror (effectively sterile) neutrinos, the ordinary-mirror neutrino mixing angles are unobservably tiny in the broken parity case. The minimal broken parity model therefore cannot simultaneously explain the solar, atmospheric and LSND data. By contrast, the unbroken parity version can explain all of the neutrino anomalies. Furthermore, we argue that the unbroken case provides the most natural explanation of the neutrino physics anomalies (irrespective of whether evidence from the LSND experiment is included) because of its characteristic maximal mixing prediction. (author)
On the origin of neutrino flavour symmetry
International Nuclear Information System (INIS)
King, Stephen F.; Luhn, Christoph
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 Δ(3n 2 ) and Δ(6n 2 ) groups, together with other examples such as Z 7 x 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.
Broken supersymmetries and shifted superpropagators
International Nuclear Information System (INIS)
Helayel-Neto, J.A.; Rabelo de Carvalho, F.A.B.; Smith, A.W.
1985-06-01
Superfield Feynman rules are derived for a general case where global supersymmetry is spontaneously broken by F-terms. The complete superspace dependence of the superpropagators is factored out and they are employed to discuss the corrections to the effective action and the non-renormalization theorems. Their coupling to external gauge superfields is also contemplated and finite matter contributions to the gaugino mass and the Fayet-Iliopoulos term are considered. (author)
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
Gauge symmetry breaking in gauge theories -- in search of clarification
Friederich, Simon
2013-01-01
The paper investigates the spontaneous breaking of gauge symmetries in gauge theories from a philosophical angle, taking into account the fact that the notion of a spontaneously broken local gauge symmetry, though widely employed in textbook expositions of the Higgs mechanism, is not supported by
Can the family group be a global symmetry
International Nuclear Information System (INIS)
Reiss, D.B.
1982-01-01
We consider the possibility that the family group may be a spontaneously broken continuous global symmetry. In the context of grand unification, the couplings of the associated Goldstone bosons to fermions can be sufficiently suppressed so as to satisfy the phenomenological bounds. For a maximal family symmetry this requires a large number of Higgs fields. (orig.)
Symmetry breaking patterns for inflation
Klein, Remko; Roest, Diederik; Stefanyszyn, David
2018-06-01
We study inflationary models where the kinetic sector of the theory has a non-linearly realised symmetry which is broken by the inflationary potential. We distinguish between kinetic symmetries which non-linearly realise an internal or space-time group, and which yield a flat or curved scalar manifold. This classification leads to well-known inflationary models such as monomial inflation and α-attractors, as well as a new model based on fixed couplings between a dilaton and many axions which non-linearly realises higher-dimensional conformal symmetries. In this model, inflation can be realised along the dilatonic direction, leading to a tensor-to-scalar ratio r ˜ 0 .01 and a spectral index n s ˜ 0 .975. We refer to the new model as ambient inflation since inflation proceeds along an isometry of an anti-de Sitter ambient space-time, which fully determines the kinetic sector.
Aniello, Paolo; Chruściński, Dariusz
2017-07-01
A symmetry witness is a suitable subset of the space of selfadjoint trace class operators that allows one to determine whether a linear map is a symmetry transformation, in the sense of Wigner. More precisely, such a set is invariant with respect to an injective densely defined linear operator in the Banach space of selfadjoint trace class operators (if and) only if this operator is a symmetry transformation. According to a linear version of Wigner’s theorem, the set of pure states—the rank-one projections—is a symmetry witness. We show that an analogous result holds for the set of projections with a fixed rank (with some mild constraint on this rank, in the finite-dimensional case). It turns out that this result provides a complete classification of the sets of projections with a fixed rank that are symmetry witnesses. These particular symmetry witnesses are projectable; i.e. reasoning in terms of quantum states, the sets of ‘uniform’ density operators of corresponding fixed rank are symmetry witnesses too.
Hairs of discrete symmetries and gravity
Energy Technology Data Exchange (ETDEWEB)
Choi, Kang Sin [Scranton Honors Program, Ewha Womans University, Seodaemun-Gu, Seoul 03760 (Korea, Republic of); Center for Fields, Gravity and Strings, CTPU, Institute for Basic Sciences, Yuseong-Gu, Daejeon 34047 (Korea, Republic of); Kim, Jihn E., E-mail: jihnekim@gmail.com [Department of Physics, Kyung Hee University, 26 Gyungheedaero, Dongdaemun-Gu, Seoul 02447 (Korea, Republic of); Center for Axion and Precision Physics Research (IBS), 291 Daehakro, Yuseong-Gu, Daejeon 34141 (Korea, Republic of); Kyae, Bumseok [Department of Physics, Pusan National University, 2 Busandaehakro-63-Gil, Geumjeong-Gu, Busan 46241 (Korea, Republic of); Nam, Soonkeon [Department of Physics, Kyung Hee University, 26 Gyungheedaero, Dongdaemun-Gu, Seoul 02447 (Korea, Republic of)
2017-06-10
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
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.
Holography without translational symmetry
Vegh, David
2013-01-01
We propose massive gravity as a holographic framework for describing a class of strongly interacting quantum field theories with broken translational symmetry. Bulk gravitons are assumed to have a Lorentz-breaking mass term as a substitute for spatial inhomogeneities. This breaks momentum-conservation in the boundary field theory. At finite chemical potential, the gravity duals are charged black holes in asymptotically anti-de Sitter spacetime. The conductivity in these systems generally exhibits a Drude peak that approaches a delta function in the massless gravity limit. Furthermore, the optical conductivity shows an emergent scaling law: $|\\sigma(\\omega)| \\approx {A \\over \\omega^{\\alpha}} + B$. This result is consistent with that found earlier by Horowitz, Santos, and Tong who introduced an explicit inhomogeneous lattice into the system.
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 ...
International Nuclear Information System (INIS)
Senjanovic, G.
1982-07-01
It is demonstrated that the spontaneous breakdown of CP invariance in grand unified theories requires the presence of intermediate mass scales. The simplest realization is provided by weakly broken left-right symmetry in the context of SU(2)sub(L) x SU(2)sub(R) x U(1)sub(B-L) model embedded in grand unified theories. (author)
A search for symmetries in the genetic code
International Nuclear Information System (INIS)
Hornos, J.E.M.; Hornos, Y.M.M.
1991-01-01
A search for symmetries based on the classification theorem of Cartan for the compact simple Lie algebras is performed to verify to what extent the genetic code is a manifestation of some underlying symmetry. An exact continuous symmetry group cannot be found to reproduce the present, universal code. However a unique approximate symmetry group is compatible with codon assignment for the fundamental amino acids and the termination codon. In order to obtain the actual genetic code, the symmetry must be slightly broken. (author). 27 refs, 3 figs, 6 tabs
International Nuclear Information System (INIS)
Wang Dianfu
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
BOOK REVIEW: Symmetry Breaking
Ryder, L. H.
2005-11-01
One of the most fruitful and enduring advances in theoretical physics during the last half century has been the development of the role played by symmetries. One needs only to consider SU(3) and the classification of elementary particles, the Yang Mills enlargement of Maxwell's electrodynamics to the symmetry group SU(2), and indeed the tremendous activity surrounding the discovery of parity violation in the weak interactions in the late 1950s. This last example is one of a broken symmetry, though the symmetry in question is a discrete one. It was clear to Gell-Mann, who first clarified the role of SU(3) in particle physics, that this symmetry was not exact. If it had been, it would have been much easier to discover; for example, the proton, neutron, Σ, Λ and Ξ particles would all have had the same mass. For many years the SU(3) symmetry breaking was assigned a mathematical form, but the importance of this formulation fell away when the quark model began to be taken seriously; the reason the SU(3) symmetry was not exact was simply that the (three, in those days) quarks had different masses. At the same time, and in a different context, symmetry breaking of a different type was being investigated. This went by the name of `spontaneous symmetry breaking' and its characteristic was that the ground state of a given system was not invariant under the symmetry transformation, though the interactions (the Hamiltonian, in effect) was. A classic example is ferromagnetism. In a ferromagnet the atomic spins are aligned in one direction only—this is the ground state of the system. It is clearly not invariant under a rotation, for that would change the ground state into a (similar but) different one, with the spins aligned in a different direction; this is the phenomenon of a degenerate vacuum. The contribution of the spin interaction, s1.s2, to the Hamiltonian, however, is actually invariant under rotations. As Coleman remarked, a little man living in a ferromagnet would
Lie-algebra approach to symmetry breaking
International Nuclear Information System (INIS)
Anderson, J.T.
1981-01-01
A formal Lie-algebra approach to symmetry breaking is studied in an attempt to reduce the arbitrariness of Lagrangian (Hamiltonian) models which include several free parameters and/or ad hoc symmetry groups. From Lie algebra it is shown that the unbroken Lagrangian vacuum symmetry can be identified from a linear function of integers which are Cartan matrix elements. In broken symmetry if the breaking operators form an algebra then the breaking symmetry (or symmetries) can be identified from linear functions of integers characteristic of the breaking symmetries. The results are applied to the Dirac Hamiltonian of a sum of flavored fermions and colored bosons in the absence of dynamical symmetry breaking. In the partially reduced quadratic Hamiltonian the breaking-operator functions are shown to consist of terms of order g 2 , g, and g 0 in the color coupling constants and identified with strong (boson-boson), medium strong (boson-fermion), and fine-structure (fermion-fermion) interactions. The breaking operators include a boson helicity operator in addition to the familiar fermion helicity and ''spin-orbit'' terms. Within the broken vacuum defined by the conventional formalism, the field divergence yields a gauge which is a linear function of Cartan matrix integers and which specifies the vacuum symmetry. We find that the vacuum symmetry is chiral SU(3) x SU(3) and the axial-vector-current divergence gives a PCAC -like function of the Cartan matrix integers which reduces to PCAC for SU(2) x SU(2) breaking. For the mass spectra of the nonets J/sup P/ = 0 - ,1/2 + ,1 - the integer runs through the sequence 3,0,-1,-2, which indicates that the breaking subgroups are the simple Lie groups. Exact axial-vector-current conservation indicates a breaking sum rule which generates octet enhancement. Finally, the second-order breaking terms are obtained from the second-order spin tensor sum of the completely reduced quartic Hamiltonian
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 ...
[Dehydration due to "mouth broken"].
Meijler, D P M; van Mossevelde, P W J; van Beek, R H T
2012-09-01
Two children were admitted to a medical centre due to dehydration after an oral injury and the extraction of a tooth. One child complained of "mouth broken". Dehydration is the most common water-electrolyte imbalance in children. Babies and young children are prone to dehydration due to their relatively large body surface area, the high percentage extracellular fluid, and the limited ability of the kidneys to conserve water. After the removal ofa tooth, after an oral trauma or in case of oral discomfort, a child is at greater risk of dehydration by reduced fluid and food intake due to oral pain and/or discomfort and anxiety to drink. In those cases, extra attention needs to be devoted to the intake of fluids.
Directory of Open Access Journals (Sweden)
Meng Cheng
2016-12-01
Full Text Available 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.
Emergent Electroweak Symmetry Breaking with Composite W, Z Bosons
Cui, Yanou; Wells, James D
2009-01-01
We present a model of electroweak symmetry breaking in a warped extra dimension where electroweak symmetry is broken at the UV (or Planck) scale. An underlying conformal symmetry is broken at the IR (or TeV) scale generating masses for the electroweak gauge bosons without invoking a Higgs mechanism. By the AdS/CFT correspondence the W,Z bosons are identified as composite states of a strongly-coupled gauge theory, suggesting that electroweak symmetry breaking is an emergent phenomenon at the IR scale. The model satisfies electroweak precision tests with reasonable fits to the S and T parameter. In particular the T parameter is sufficiently suppressed since the model naturally admits a custodial SU(2) symmetry. The composite nature of the W,Z-bosons provide a novel possibility of unitarizing WW scattering via form factor suppression. Constraints from LEP and the Tevatron as well as discovery opportunities at the LHC are discussed for these composite electroweak gauge bosons.
Structural symmetry and protein function.
Goodsell, D S; Olson, A J
2000-01-01
The majority of soluble and membrane-bound proteins in modern cells are symmetrical oligomeric complexes with two or more subunits. The evolutionary selection of symmetrical oligomeric complexes is driven by functional, genetic, and physicochemical needs. Large proteins are selected for specific morphological functions, such as formation of rings, containers, and filaments, and for cooperative functions, such as allosteric regulation and multivalent binding. Large proteins are also more stable against denaturation and have a reduced surface area exposed to solvent when compared with many individual, smaller proteins. Large proteins are constructed as oligomers for reasons of error control in synthesis, coding efficiency, and regulation of assembly. Symmetrical oligomers are favored because of stability and finite control of assembly. Several functions limit symmetry, such as interaction with DNA or membranes, and directional motion. Symmetry is broken or modified in many forms: quasisymmetry, in which identical subunits adopt similar but different conformations; pleomorphism, in which identical subunits form different complexes; pseudosymmetry, in which different molecules form approximately symmetrical complexes; and symmetry mismatch, in which oligomers of different symmetries interact along their respective symmetry axes. Asymmetry is also observed at several levels. Nearly all complexes show local asymmetry at the level of side chain conformation. Several complexes have reciprocating mechanisms in which the complex is asymmetric, but, over time, all subunits cycle through the same set of conformations. Global asymmetry is only rarely observed. Evolution of oligomeric complexes may favor the formation of dimers over complexes with higher cyclic symmetry, through a mechanism of prepositioned pairs of interacting residues. However, examples have been found for all of the crystallographic point groups, demonstrating that functional need can drive the evolution of
Flavor universal dynamical electroweak symmetry breaking
International Nuclear Information System (INIS)
Burdman, G.; Evans, N.
1999-01-01
The top condensate seesaw mechanism of Dobrescu and Hill allows electroweak symmetry to be broken while deferring the problem of flavor to an electroweak singlet, massive sector. We provide an extended version of the singlet sector that naturally accommodates realistic masses for all the standard model fermions, which play an equal role in breaking electroweak symmetry. The models result in a relatively light composite Higgs sector with masses typically in the range of (400 - 700) GeV. In more complete models the dynamics will presumably be driven by a broken gauged family or flavor symmetry group. As an example of the higher scale dynamics a fully dynamical model of the quark sector with a GIM mechanism is presented, based on an earlier top condensation model of King using broken family gauge symmetry interactions (that model was itself based on a technicolor model of Georgi). The crucial extra ingredient is a reinterpretation of the condensates that form when several gauge groups become strong close to the same scale. A related technicolor model of Randall which naturally includes the leptons too may also be adapted to this scenario. We discuss the low energy constraints on the massive gauge bosons and scalars of these models as well as their phenomenology at the TeV scale. copyright 1999 The American Physical Society
Alvarez-Gaumé, Luís; Kounnas, Costas; Marino, M; Alvarez-Gaume, Luis; Distler, Jacques; Kounnas, Costas; Marino, Marcos
1996-01-01
We analyze the possible soft breaking of N=2 supersymmetric Yang-Mills theory with and without matter flavour preserving the analyticity properties of the Seiberg-Witten solution. For small supersymmetry breaking parameter with respect to the dynamical scale of the theory we obtain an exact expression for the effective potential. We describe in detail the onset of the confinement transition and some of the patterns of chiral symmetry breaking. If we extrapolate the results to the limit where supersymmetry decouples, we obtain hints indicating that perhaps a description of the QCD vacuum will require the use of Lagrangians containing simultaneously mutually non-local degrees of freedom (monopoles and dyons).
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.
Self Derogation and Childhood Broken Home
Kaplan, Howard B; Pokorny, Alex D.
1971-01-01
The data from this study makes clear that it is not the fact of broken homes per se that is related to self derogation but rather the particular characteristics of the broken home situation. Prediction of self derogation is also contingent upon such subject characteristics as race, sex and social class. (Author/CG)
"Broken Expectations" from a Global Business Perspective
Koca, A.; Karapanos, E.; Brombacher, A.C.
2009-01-01
Especially in the past few years, there has been an increase in the rejection rate of interactive consumer electronics products in the field, not due to broken hardware or software, but due to ‘broken expectations’ of users. However, operational methods to capture triggering contextual reasons are
Güngör, Özenç; Starkman, Glenn D.; Stora, Raymond
This work is dedicated to the memory of Raymond Stora (1930-2015). $SU(2)_L$ is the simplest spontaneous symmetry breaking (SSB) non-Abelian gauge theory: a complex scalar doublet $\\phi=\\frac{1}{\\sqrt{2}}\\begin{bmatrix}H+i\\pi_3-\\pi_2 +i\\pi_1\\end{bmatrix}\\equiv\\frac{1}{\\sqrt{2}}\\tilde{H}e^{2i\\tilde{t}\\cdot\\tilde{\\vec{\\pi}}/}\\begin{bmatrix}10\\end{bmatrix}$ and a vector $\\vec{W}^\\mu$. In Landau gauge, $\\vec{W}^\\mu$ is transverse, $\\vec{\\tilde{\\pi}}$ are massless derivatively coupled Nambu-Goldstone bosons (NGB). A global shift symmetry enforces $m^{2}_{\\tilde{\\pi}}=0$. We observe that on-shell T-matrix elements of physical states $\\vec{W}^\\mu$,$\\phi$ are independent of global $SU(2)_{L}$ transformations, and the associated global current is exactly conserved for amplitudes of physical states. We identify two towers of "1-soft-pion" global Ward-Takahashi Identities (WTI), which govern the $\\phi$-sector, and represent a new global symmetry, $SU(2)_L\\otimes$BRST, a symmetry not of the Lagrangian but of the physical...
International Nuclear Information System (INIS)
Souriau, J.M.
1984-01-01
The sky uniformity can be noticed in studying the repartition of objects far enough. The sky isotropy description uses space rotations. The group theory elements will allow to give a meaning at the same time precise and general to the word a ''symmetry''. Universe models are reviewed, which must have both of the following qualities: - conformity with the physic known laws; - rigorous symmetry following one of the permitted groups. Each of the models foresees that universe evolution obeys an evolution equation. Expansion and big-bang theory are recalled. Is universe an open or closed space. Universe is also electrically neutral. That leads to a work hypothesis: the existing matter is not given data of universe but it appeared by evolution from nothing. Problem of matter and antimatter is then raised up together with its place in universe [fr
Dynamically broken gauge model without fundamental scalar fields
International Nuclear Information System (INIS)
Snyderman, N.J.; Guralnik, G.S.
1976-01-01
It is shown that the structure that must be generated by dynamical symmetry breaking solutions to gauge theories can be explicitly implemented with a 4-fermion interaction. This structure arises in order to obtain consistency with the constraints imposed by a Goldstone commutator proportional to [anti psi psi]. One demonstrates these ideas within the context of axial electrodynamics, dynamically breaking chiral symmetry. As a pre-requisite it is shown how the Nambu-Jona-Lasinio model becomes renormalizable with respect to a systematic approximation scheme that respects the Goldstone commutator of dynamically broken chiral symmetry to each order of approximation. (This approximation scheme is equivalent to a l/N expansion, where N is set to unity at the end of the calculations). This solution generates new interactions not explicitly present in the original Lagrangian and does not have a 4-fermion contact interaction. The renormalized Green's functions are shown to correspond to those of the sigma-model, summed as though the fermions had N components, and for which lambda 0 = 2g 0 2 . This correspondence is exact except for the possibility that the renormalized coupling of the Nambu-Jona-Lasinio model may be a determined number
Dynamically broken gauge model without fundamental scalar fields
Energy Technology Data Exchange (ETDEWEB)
Snyderman, N. J.; Guralnik, G. S.
1976-01-01
It is shown that the structure that must be generated by dynamical symmetry breaking solutions to gauge theories can be explicitly implemented with a 4-fermion interaction. This structure arises in order to obtain consistency with the constraints imposed by a Goldstone commutator proportional to (anti psi psi). One demonstrates these ideas within the context of axial electrodynamics, dynamically breaking chiral symmetry. As a pre-requisite it is shown how the Nambu-Jona-Lasinio model becomes renormalizable with respect to a systematic approximation scheme that respects the Goldstone commutator of dynamically broken chiral symmetry to each order of approximation. (This approximation scheme is equivalent to a l/N expansion, where N is set to unity at the end of the calculations). This solution generates new interactions not explicitly present in the original Lagrangian and does not have a 4-fermion contact interaction. The renormalized Green's functions are shown to correspond to those of the sigma-model, summed as though the fermions had N components, and for which lambda/sub 0/ = 2g/sub 0//sup 2/. This correspondence is exact except for the possibility that the renormalized coupling of the Nambu-Jona-Lasinio model may be a determined number.
Symmetry realization via a dynamical inverse Higgs mechanism
Rothstein, Ira Z.; Shrivastava, Prashant
2018-05-01
The Ward identities associated with spontaneously broken symmetries can be saturated by Goldstone bosons. However, when space-time symmetries are broken, the number of Goldstone bosons necessary to non-linearly realize the symmetry can be less than the number of broken generators. The loss of Goldstones may be due to a redundancy or the generation of a gap. In either case the associated Goldstone may be removed from the spectrum. This phenomena is called an Inverse Higgs Mechanism (IHM) and its appearance has a well defined mathematical condition. However, there are cases when a Goldstone boson associated with a broken generator does not appear in the low energy theory despite the lack of the existence of an associated IHM. In this paper we will show that in such cases the relevant broken symmetry can be realized, without the aid of an associated Goldstone, if there exists a proper set of operator constraints, which we call a Dynamical Inverse Higgs Mechanism (DIHM). We consider the spontaneous breaking of boosts, rotations and conformal transformations in the context of Fermi liquids, finding three possible paths to symmetry realization: pure Goldstones, no Goldstones and DIHM, or some mixture thereof. We show that in the two dimensional degenerate electron system the DIHM route is the only consistent way to realize spontaneously broken boosts and dilatations, while in three dimensions these symmetries could just as well be realized via the inclusion of non-derivatively coupled Goldstone bosons. We present the action, including the leading order non-linearities, for the rotational Goldstone (angulon), and discuss the constraint associated with the possible DIHM that would need to be imposed to remove it from the spectrum. Finally we discuss the conditions under which Goldstone bosons are non-derivatively coupled, a necessary condition for the existence of a Dynamical Inverse Higgs Constraint (DIHC), generalizing the results for Vishwanath and Wantanabe.
Gapless Symmetry-Protected Topological Order
Directory of Open Access Journals (Sweden)
Thomas Scaffidi
2017-11-01
Full Text Available We introduce exactly solvable gapless quantum systems in d dimensions that support symmetry-protected topological (SPT edge modes. Our construction leads to long-range entangled, critical points or phases that can be interpreted as critical condensates of domain walls “decorated” with dimension (d-1 SPT systems. Using a combination of field theory and exact lattice results, we argue that such gapless SPT systems have symmetry-protected topological edge modes that can be either gapless or symmetry broken, leading to unusual surface critical properties. Despite the absence of a bulk gap, these edge modes are robust against arbitrary symmetry-preserving local perturbations near the edges. In two dimensions, we construct wave functions that can also be interpreted as unusual quantum critical points with diffusive scaling in the bulk but ballistic edge dynamics.
International Nuclear Information System (INIS)
Choi, K.; Kaplan, D.B.; Nelson, A.E.
1993-01-01
Conventional solutions to the strong CP problem all require the existence of global symmetries. However, quantum gravity may destroy global symmetries, making it hard to understand why the electric dipole moment of the neutron (EDMN) is so small. We suggest here that CP is actually a discrete gauge symmetry, and is therefore not violated by quantum gravity. We show that four-dimensional CP can arise as a discrete gauge symmetry in theories with dimensional compactification, if the original number of Minkowski dimensions equals 8k+1, 8k+2 or 8k+3, and if there are certain restrictions on the gauge group; these conditions are met by superstrings. CP may then be broken spontaneously below 10 9 GeV, explaining the observed CP violation in the kaon system without inducing a large EDMN. We discuss the phenomenology of such models, as well as the peculiar properties of cosmic 'SP strings' which could be produced at the compactification scale. Such strings have the curious property that a particle carried around the string is turned into its CP conjugate. A single CP string renders four-dimensional space-time nonorientable. (orig.)
Discrete symmetries and their stringy origin
International Nuclear Information System (INIS)
Mayorga Pena, Damian Kaloni
2014-05-01
Discrete symmetries have proven to be very useful in controlling the phenomenology of theories beyond the standard model. In this work we explore how these symmetries emerge from string compactifications. Our approach is twofold: On the one hand, we consider the heterotic string on orbifold backgrounds. In this case the discrete symmetries can be derived from the orbifold conformal field theory, and it can be shown that they are in close relation with the orbifold geometry. We devote special attention to R-symmetries, which arise from discrete remnants of the Lorentz group in compact space. Further we discuss the physical implications of these symmetries both in the heterotic mini-landscape and in newly constructed models based on the Z 2 x Z 4 orbifold. In both cases we observe that the discrete symmetries favor particular locations in the orbifold where the particles of standard model should live. On the other hand we consider a class of F-theory models exhibiting an SU(5) gauge group, times additional U(1) symmetries. In this case, the smooth compactification background does not permit us to track the discrete symmetries as transparently as in orbifold models. Hence, we follow a different approach and search for discrete subgroups emerging after the U(1)s are broken. We observe that in this approach it is possible to obtain the standard Z 2 matter parity of the MSSM.
Cosmoparticle physics of family symmetry breaking
International Nuclear Information System (INIS)
Khlopov, M.Yu.
1993-07-01
The foundations of both particle theory and cosmology are hidden at super energy scale and can not be tested by direct laboratory means. Cosmoparticle physics is developed to probe these foundations by the proper combination of their indirect effects, thus providing definite conclusions on their reliability. Cosmological and astrophysical tests turn to be complementary to laboratory searches of rare processes, induced by new physics, as it can be seen in the case of gauge theory of broken symmetry of quark and lepton families, ascribing to the hierarchy of the horizontal symmetry breaking the observed hierarchy of masses and the mixing between quark and lepton families. 36 refs
Off-shell Ward identities and gauge symmetries in string theory
International Nuclear Information System (INIS)
Porrati, M.
1989-01-01
I describe a new method of obtaining gauge-symmetry transformation laws for the effective lagrangian of an arbitrary string theory. The method applies to exact as well as spontaneously broken gauge symmetries. The transformation laws, exact to all orders in α' are determined inductively in the number of fields by the corresponding off-shell Ward identities. The case of broken supersymmetry is examined in some detail. (orig.)
International Nuclear Information System (INIS)
Chaichian, M.; Montonen, C.; Perez Rojas, H.
1991-01-01
The completely different conservation properties of charges associated to unbroken and broken symmetries are discussed. The impossibility of establishing a conservation law for nondegenerate Hilbert space representations in the broken case leads to a reciprocal of Coleman's theorem. The quantum statistical implication is that these charges cannot be introduced as conserved operators in the density matrix. (orig.)
Extensions of automorphisms and gauge symmetries
International Nuclear Information System (INIS)
Buchholz, D.; Doplicher, S.; Longo, R.; Roberts, J.E.
1993-01-01
We characterize the automophisms of a C*-algebra A which extend to automorphisms of the crossed product B of A by a compact group dual. The case where the inclusion A contains or equal to B is equipped with a group of automorphisms commuting with the dual action is also treated. These results are applied to the analysis of broken gauge symmetries in Quantum Field Theory to draw conclusions on the structure of the degenerate vacua on the field algebra. (orig.)
Scale gauge symmetry and the standard model
International Nuclear Information System (INIS)
Sola, J.
1990-01-01
This paper speculates on a version of the standard model of the electroweak and strong interactions coupled to gravity and equipped with a spontaneously broken, anomalous, conformal gauge symmetry. The scalar sector is virtually absent in the minimal model but in the general case it shows up in the form of a nonlinear harmonic map Lagrangian. A Euclidean approach to the phenological constant problem is also addressed in this framework
Is space-time symmetry a suitable generalization of parity-time symmetry?
International Nuclear Information System (INIS)
Amore, Paolo; Fernández, Francisco M.; Garcia, Javier
2014-01-01
We discuss space-time symmetric Hamiltonian operators of the form H=H 0 +igH ′ , where H 0 is Hermitian and g real. H 0 is invariant under the unitary operations of a point group G while H ′ is invariant under transformation by elements of a subgroup G ′ 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
Domain walls and the C P anomaly in softly broken supersymmetric QCD
Draper, Patrick
2018-04-01
In ordinary QCD with light, degenerate, fundamental flavors, C P symmetry is spontaneously broken at θ =π , and domain wall solutions connecting the vacua can be constructed in chiral perturbation theory. In some cases the breaking of C P saturates a 't Hooft anomaly, and anomaly inflow requires nontrivial massless excitations on the domain walls. Analogously, C P can be spontaneously broken in supersymmetric QCD (SQCD) with light flavors and small soft breaking parameters. We study C P breaking and domain walls in softly broken SQCD with Nfcomputed at leading order in the soft breaking parameters, producing a phase diagram for the stable wall trajectory. We also comment on domain walls in the similar case of QCD with an adjoint and fundamental flavors, and on the impact of adding an axion in this theory.
Inflation via Gravitino Condensation in Dynamically Broken Supergravity
Alexandre, Jean; Mavromatos, Nick E
2015-01-01
Gravitino-condensate-induced inflation via the super-Higgs effect is a UV-motivated scenario for both inflating the early universe and breaking local supersymmetry dynamically, entirely independent of any coupling to external matter. As an added benefit, this also removes the (as of yet unobserved) massless Goldstino associated to global supersymmetry breaking from the particle spectrum. In this review we detail the pertinent properties and outline previously hidden details of the various steps required in this context in order to make contact with current inflationary phenomenology. The class of models of SUGRA we use to exemplify our approach are minimal four-dimensional N=1 supergravity and conformal extensions thereof (with broken conformal symmetry). Therein, the gravitino condensate itself can play the role of the inflaton, however the requirement of slow-roll necessitates unnaturally large values of the wave-function renormalisation. Nevertheless, there is an alternative scenario that may provide Staro...
Supersymmetry and intermediate symmetry breaking in SO(10) superunification
International Nuclear Information System (INIS)
Asatryan, H.M.; Ioannisyan, A.N.
1985-01-01
A scheme of simultaneous breakdown of intermediate symmetry SO(10) → SU(3)sub(c) x U(1) x SU(2)sub(L) x SU(2)sub(R) and supersymmetry by means of a single scale parameter is suggested. This intermediate symmetry, which is preferable physically, owing to the broken supersymmetry has a minimum lying lower than SU(4) x SU(2)sub(L) x SU(2)sub(R). The intermediate symmetry is broken by the vacuum expectation value of the Higgs superfields. Owing to the quantum corrections the potential minimum turns out to correspond to breakdown of the intermediate symmetry up to the standard group SU(3)sub(c) x SU(2)sub(L) x U(1)sub(y). The value of the Weinberg angle is less than that in the supersymmetric SU(5) model and agrees with the experiment
Neutrino Masses with Inverse Hierarchy from Broken $L_{e}-L_{\\mu}-L_{\\tau}$: a Reappraisal
Altarelli, Guido; Altarelli, Guido; Franceschini, Roberto
2006-01-01
We discuss a class of models of neutrino masses and mixings with inverse hierarchy based on a broken U(1)_F flavour symmetry with charge L_e-L_\\mu-L_\\tau. The symmetry breaking sector receives separate contributions from flavon vev breaking terms and from soft mass breaking in the right handed Majorana sector. The model is able to reproduce in a natural way all observed features of the charged lepton mass spectrum and of neutrino masses and mixings (even with arbitrarily small \\theta_{13}), with the exception of a moderate fine tuning which is needed to accomodate the observed small value of r = Delta m^2_{sol} / Delta m^2_{atm}.
Perilaku Agresif Siswa dari Keluarga Broken Home
Directory of Open Access Journals (Sweden)
Randi Pratama
2016-12-01
Full Text Available This research is based because of the aggressive behavior shown by the students, especially students who come from a broken home. The purpose of this study is to describe the aggressive behavior that is owned by a student who comes from a broken home in terms of attacking people physically, verbally, and damaging and destroying property and wealth of others. The results of this research shows that in general student’s aggressivebehavior are on average level. Implications of research in guidance and counseling is as the basis for programs to prevent and cope with aggressive behavior that is owned by the students, especially students who come from a broken home. Cooperation with the homeroom teacher mentors, teachers and other school personnel will also help identify students who have an aggressive behavior, especially students who come from a broken home to immediately provided services.
Open-string models with broken supersymmetry
International Nuclear Information System (INIS)
Sagnotti, A.
2002-01-01
I review the salient features of three classes of open-string models with broken supersymmetry. These suffice to exhibit, in relatively simple settings, the two phenomena of 'brane supersymmetry' and 'brane supersymmetry breaking'. In the first class of models, to lowest order supersymmetry is broken both in the closed and in the open sectors. In the second class of models, to lowest order supersymmetry is broken in the closed sector, but is exact in the open sector, at least for the low-lying modes, and often for entire towers of string excitations. Finally, in the third class of models, to lowest order supersymmetry is exact in the closed (bulk) sector, but is broken in the open sector. Brane supersymmetry breaking provides a natural solution to some old difficulties met in the construction of open-string vacua. (author)
Open-string models with broken supersymmetry
International Nuclear Information System (INIS)
Sagnotti, Augusto
2000-01-01
We review the salient features of three classes of open-string models with broken supersymmetry. These suffice to exhibit, in relatively simple settings, the two phenomena of 'brane supersymmetry' and 'brane supersymmetry breaking'. In the first class of models, to lowest order supersymmetry is broken both in the closed and in the open sectors. In the second class of models, to lowest order supersymmetry is broken in the closed sector, but is exact in the open sector, at least for the low-lying modes, and often for entire towers of string excitations. Finally, in the third class of models, to lowest order supersymmetry is exact in the closed (bulk) sector, but is broken in the open sector. Brane supersymmetry breaking provides a natural solution to some old difficulties met in the construction of open-string vacua
Subconjunctival Hemorrhage (Broken Blood Vessel in Eye)
Subconjunctival hemorrhage (broken blood vessel in eye) Overview A subconjunctival hemorrhage (sub-kun-JUNK-tih-vul HEM-uh-ruj) ... may not even realize you have a subconjunctival hemorrhage until you look in the mirror and notice ...
Phenomenology of muon number violation in spontaneously broken gauge theories
International Nuclear Information System (INIS)
Shanker, O.U.
1980-01-01
The phenomenology of muon number violation in gauge theories of weak and electromagnetic interactions is studied. In the first chapter a brief introduction to the concept of muon number and to spontaneously broken gauge theories is given. A review of the phenomenology and experimental situation regarding different muon number violating processes is made in the second chapter. A detailed phenomenological study of the μe conversion process μ - + (A,Z) → e - + (A,Z) is given in the third chapter. In the fourth chapter some specific gauge theories incorporating spontaneously broken horizontal gauge symmetries between different fermion generations are discussed with special reference to muon number violation in the theories. The μe conversion process seems to be a good process to search for muon number violation if it occurs. The K/sub L/-K/sub S/ mass difference is likely to constrain muon number violating rates to lie far below present experimental limits unless strangeness changing neutral currents changing strangeness by two units are suppressed
Quark diquark symmetry breaking
International Nuclear Information System (INIS)
Souza, M.M. de
1980-01-01
Assuming the baryons are made of quark-diquark pairs, the wave functions for the 126 allowed ground states are written. The quark creation and annihilations operators are generalized to describe the quark-diquark structure in terms of a parameter σ. Assuming that all quark-quark interactions are mediated by gluons transforming like an octet of vector mesons, the effective Hamiltonian and the baryon masses as constraint equations for the elements of the mass matrix is written. The symmetry is the SU(6) sub(quark)x SU(21) sub(diquark) broken by quark-quark interactions respectively invariant under U(6), U(2) sub(spin), U(3) and also interactions transforming like the eighth and the third components of SU(3). In the limit of no quark-diquark structure (σ = 0), the ground state masses is titted to within 1% of the experimental data, except for the Δ(1232), where the error is almost 2%. Expanding the decuplet mass equations in terms of σ and keeping terms only up to the second order, this error is reduced to 67%. (Author) [pt
Introduction to symmetry-breaking phenomena in physics
CERN. Geneva. Audiovisual Unit
2001-01-01
The notion of broken symmetries started slowly to emerge in the 19th century. The early studies of Pasteur on the parity asymmetry of life, the studies of Curie on piezoelectricity and on the symmetries of effects versus the symmetry of causes ( which clearly excluded spontaneous symmetry breaking), are important historical landmarks. However the possibility of spontaneous symmetry breaking within the usual principles of statistical mechanics, waited for the work of Peierls and Onsager. The whole theory of phase transitions and critical phenomena, as well as the construction of field theoretic models as long distance limit of yet unknown physics, relies nowadays on the concept of criticality associated to spontaneous symmetry breaking. The phenomena of Goldstone bosons, of Meissner-Higgs effects, are central to the theory of condensed matter as well as to particle physics. In cosmology as well, the various inflationary scenarios begin similarly with this same concept. The three lectures will provide a simple ...
Scale-chiral symmetry, ω meson, and dense baryonic matter
Ma, Yong-Liang; Rho, Mannque
2018-05-01
It is shown that explicitly broken scale symmetry is essential for dense skyrmion matter in hidden local symmetry theory. Consistency with the vector manifestation fixed point for the hidden local symmetry of the lowest-lying vector mesons and the dilaton limit fixed point for scale symmetry in dense matter is found to require that the anomalous dimension (|γG2| ) of the gluon field strength tensor squared (G2 ) that represents the quantum trace anomaly should be 1.0 ≲|γG2|≲3.5 . The magnitude of |γG2| estimated here will be useful for studying hadron and nuclear physics based on the scale-chiral effective theory. More significantly, that the dilaton limit fixed point can be arrived at with γG2≠0 at some high density signals that scale symmetry can arise in dense medium as an "emergent" symmetry.
Chiral symmetry breaking and confinement - solutions of relativistic wave equations
International Nuclear Information System (INIS)
Murugesan, P.
1983-01-01
In this thesis, an attempt is made to explore the question whether confinement automatically leads to chiral symmetry breaking. While it should be accepted that chiral symmetry breaking manifests in nature in the absence of scalar partners of pseudoscalar mesons, it does not necessarily follow that confinement should lead to chiral symmetry breaking. If chiral conserving forces give rise to observed spectrum of hadrons, then the conjuncture that confinement is responsible for chiral symmetry breaking is not valid. The method employed to answer the question whether confinement leads to chiral symmetry breaking or not is to solve relativistic wave equations by introducing chiral conserving as well as chiral breaking confining potentials and compare the results with experimental observations. It is concluded that even though chiral symmetry is broken in nature, confinement of quarks need not be the cause of it
Dark matter and global symmetries
Directory of Open Access Journals (Sweden)
Yann Mambrini
2016-09-01
Full Text Available 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.
Softly Broken Lepton Numbers: an Approach to Maximal Neutrino Mixing
International Nuclear Information System (INIS)
Grimus, W.; Lavoura, L.
2001-01-01
We discuss models where the U(1) symmetries of lepton numbers are responsible for maximal neutrino mixing. We pay particular attention to an extension of the Standard Model (SM) with three right-handed neutrino singlets in which we require that the three lepton numbers L e , L μ , and L τ be separately conserved in the Yukawa couplings, but assume that they are softly broken by the Majorana mass matrix M R of the neutrino singlets. In this framework, where lepton-number breaking occurs at a scale much higher than the electroweak scale, deviations from family lepton number conservation are calculable, i.e., finite, and lepton mixing stems exclusively from M R . We show that in this framework either maximal atmospheric neutrino mixing or maximal solar neutrino mixing or both can be imposed by invoking symmetries. In this way those maximal mixings are stable against radiative corrections. The model which achieves maximal (or nearly maximal) solar neutrino mixing assumes that there are two different scales in M R and that the lepton number (dash)L=L e -L μ -L τ 1 is conserved in between them. We work out the difference between this model and the conventional scenario where (approximate) (dash)L invariance is imposed directly on the mass matrix of the light neutrinos. (author)
Spontaneous breakdown of PT symmetry in the complex Coulomb ...
Indian Academy of Sciences (India)
P T symmetry is spontaneously broken, however, for complex values of the form L = − 1 2 + i . In this case the potential remains P T -symmetric, while the two independent solutions are transformed to each other by the P T operation and at the same time, the two series of discrete energy eigenvalues turn into each ...
Nonperturbative calculation of symmetry breaking in quantum field theory
Bender, Carl M.; Milton, Kimball A.
1996-01-01
A new version of the delta expansion is presented, which, unlike the conventional delta expansion, can be used to do nonperturbative calculations in a self-interacting scalar quantum field theory having broken symmetry. We calculate the expectation value of the scalar field to first order in delta, where delta is a measure of the degree of nonlinearity in the interaction term.
Topological symmetry breakdown in cholesterics, nematics, and 3He
International Nuclear Information System (INIS)
Balachandran, A.P.; Lizzi, F.; Rodgers, V.G.J.
1984-01-01
Cholesterics, uniaxial and biaxial nematics, and the dipole-free A phase of superfluid 3 He are characterized by order parameters which are left invariant by suitable ''symmetry'' groups H. We show that in the presence of defects, the full group H may not be implementable on the states because of topological obstructions. Thus H is topologically broken in the presence of suitable defects
CP and other gauge symmetries in string theory
International Nuclear Information System (INIS)
Dine, M.; Leigh, R.G.; MacIntire, D.A.
1992-01-01
We argue that CP is a gauge symmetry in string theory. As a consequence, CP cannot be explicitly broken either perturbatively or nonperturbatively; there can be no nonperturbative CP-violating parameters. String theory is thus an example of a theory where all θ angles arise due to spontaneous CP violation, and are in principle calculable
Symmetries in eleven dimensional supergravity compactified on a parallelized seven sphere
Englert, F; Spindel, P
1983-01-01
We analyse, in eleven-dimensional supergravity compactified on S7, the spontaneous symmetry breaking induced by a spontaneous parallelization of the sphere. The eight supersymmetries are broken at a common scale and the SO(8) gauge group is reduced to Spin (7). Such a large residual symmetry has a simple geometrical significance revealed through use of octonions; this is explained in elementary terms.
Bosonization, dual transformation and non-local hidden symmetry in two dimensions
International Nuclear Information System (INIS)
Hata, Hiroyuki
1985-01-01
The non-local hidden symmetry is investigated in the bosonized non-abelian Thirring model and the dual representation of the chiral model. In these representations the first non-local symmetry is spontaneously broken in naive pertubation theory. (orig.)
Large lepton mixings from continuous symmetries
International Nuclear Information System (INIS)
Everett, Lisa; Ramond, Pierre
2007-01-01
Within the broad context of quark-lepton unification, we investigate the implications of broken continuous family symmetries which result from requiring that in the limit of exact symmetry, the Dirac mass matrices yield hierarchical masses for the quarks and charged leptons, but lead to degenerate light neutrino masses as a consequence of the seesaw mechanism, without requiring hierarchical right-handed neutrino mass terms. Quark mixing is then naturally small and proportional to the size of the perturbation, but lepton mixing is large as a result of degenerate perturbation theory, shifted from maximal mixing by the size of the perturbation. Within this approach, we study an illustrative two-family prototype model with an SO(2) family symmetry, and discuss extensions to three-family models
The symmetry of large N=4 holography
International Nuclear Information System (INIS)
Gaberdiel, Matthias R.; Peng, Cheng
2014-01-01
For the proposed duality relating a family of N=4 superconformal coset models to a certain supersymmetric higher spin theory on AdS_3, the asymptotic symmetry algebra of the bulk description is determined. It is shown that, depending on the choice of the boundary charges, one may obtain either the linear or the non-linear superconformal algebra on the boundary. We compare the non-linear version of the asymptotic symmetry algebra with the non-linear coset algebra and find non-trivial agreement in the ’t Hooft limit, thus giving strong support for the proposed duality. As a by-product of our analysis we also show that the W_∞ symmetry of the coset theory is broken under the exactly marginal perturbation that preserves the N=4 superconformal algebra
Recurrence and symmetry of time series: Application to transition detection
International Nuclear Information System (INIS)
Girault, Jean-Marc
2015-01-01
Highlights: •A new theoretical framework based on the symmetry concept is proposed. •Four types of symmetry present in any time series were analyzed. •New descriptors make possible the analysis of regime changes in logistic systems. •Chaos–chaos, chaos–periodic, symmetry-breaking, symmetry-increasing bifurcations can be detected. -- Abstract: The study of transitions in low dimensional, nonlinear dynamical systems is a complex problem for which there is not yet a simple, global numerical method able to detect chaos–chaos, chaos–periodic bifurcations and symmetry-breaking, symmetry-increasing bifurcations. We present here for the first time a general framework focusing on the symmetry concept of time series that at the same time reveals new kinds of recurrence. We propose several numerical tools based on the symmetry concept allowing both the qualification and quantification of different kinds of possible symmetry. By using several examples based on periodic symmetrical time series and on logistic and cubic maps, we show that it is possible with simple numerical tools to detect a large number of bifurcations of chaos–chaos, chaos–periodic, broken symmetry and increased symmetry types
The geometric role of symmetry breaking in gravity
International Nuclear Information System (INIS)
Wise, Derek K
2012-01-01
In gravity, breaking symmetry from a group G to a group H plays the role of describing geometry in relation to the geometry of the homogeneous space G/H. The deep reason for this is Cartan's 'method of equivalence,' giving, in particular, an exact correspondence between metrics and Cartan connections. I argue that broken symmetry is thus implicit in any gravity theory, for purely geometric reasons. As an application, I explain how this kind of thinking gives a new approach to Hamiltonian gravity in which an observer field spontaneously breaks Lorentz symmetry and gives a Cartan connection on space.
Spontaneous symmetry breaking in 4-dimensional heterotic string
International Nuclear Information System (INIS)
Maharana, J.
1989-07-01
The evolution of a 4-dimensional heterotic string is considered in the background of its massless excitations such as graviton, antisymmetric tensor, gauge fields and scalar bosons. The compactified bosonic coordinates are fermionized. The world-sheet supersymmetry requirement enforces Thirring-like four fermion coupling to the background scalar fields. The non-abelian gauge symmetry is exhibited through the Ward identities of the S-matrix elements. The spontaneous symmetry breaking mechanism is exhibited through the broken Ward identities. An effective 4-dimensional action is constructed and the consequence of spontaneous symmetry breaking is envisaged for the effective action. 19 refs
Dynamics of symmetry breaking during quantum real-time evolution in a minimal model system.
Heyl, Markus; Vojta, Matthias
2014-10-31
One necessary criterion for the thermalization of a nonequilibrium quantum many-particle system is ergodicity. It is, however, not sufficient in cases where the asymptotic long-time state lies in a symmetry-broken phase but the initial state of nonequilibrium time evolution is fully symmetric with respect to this symmetry. In equilibrium, one particular symmetry-broken state is chosen as a result of an infinitesimal symmetry-breaking perturbation. From a dynamical point of view the question is: Can such an infinitesimal perturbation be sufficient for the system to establish a nonvanishing order during quantum real-time evolution? We study this question analytically for a minimal model system that can be associated with symmetry breaking, the ferromagnetic Kondo model. We show that after a quantum quench from a completely symmetric state the system is able to break its symmetry dynamically and discuss how these features can be observed experimentally.
Symmetry breaking in gauge glasses
International Nuclear Information System (INIS)
Hansen, K.
1988-09-01
In order to explain why nature selects the gauge groups of the Standard Model, Brene and Nielsen have proposed a way to break gauge symmetry which does not rely on the existence of a Higgs field. The observed gauge groups will in this scheme appear as the only surviving ones when this mechanism is applied to a random selection of gauge groups. The essential assumption is a discrete space-time with random couplings. Some working assumptions were made for computational reasons of which the most important is that quantum fluctuations were neclected. This work presents an example which under the same conditions show that a much wider class of groups than predicted by Brene and Nielsen will be broken. In particular no possible Standard Model Group survives unbroken. Numerical calculations support the analytical result. (orig.)
Chiral symmetry and chiral-symmetry breaking
International Nuclear Information System (INIS)
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
Vacuum solutions of a gravity model with vector-induced spontaneous Lorentz symmetry breaking
International Nuclear Information System (INIS)
Bertolami, O.; Paramos, J.
2005-01-01
We study the vacuum solutions of a gravity model where Lorentz symmetry is spontaneously broken once a vector field acquires a vacuum expectation value. Results are presented for the purely radial Lorentz symmetry breaking (LSB), radial/temporal LSB and axial/temporal LSB. The purely radial LSB result corresponds to new black hole solutions. When possible, parametrized post-Newtonian parameters are computed and observational boundaries used to constrain the Lorentz symmetry breaking scale
e +e- modes and U(1) spontaneous chiral symmetry breaking
International Nuclear Information System (INIS)
Steininger, K.
1992-01-01
In this paper, motivated by evidence for a chiral phase transition in strong coupling lattice QED, the authors calculate the two-particle spectrum of the broken QED phase. This is done in the framework of a Nambu and Jona-Lasinio model with U(1) symmetry including chiral symmetry and symmetry breaking properties of QED. The second order chiral phase transition behavior in our model and in lattice QED are in excellent agreement. The authors then present a detailed analysis of the spectra of the e + e - modes in the broken phase. The authors examine whether these modes have any possible relationship to the narrow e + e - resonances found in soft heavy ion collisions at GSL. The authors' answer is negative
Spontaneously broken version of N=4 supersymmetry
International Nuclear Information System (INIS)
Terent'ev, M.V.
1989-01-01
The special scenario of reduction from the space of D=10 dimensions is used to construct the theory with describes interaction of supergravity with only one multiplet of matter in the framework of spontaneously broken N=4 supersymmetry. 6 refs.; 1 fig
Of Slot Machines and Broken Test Tubes
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 5. Of Slot Machines and Broken Test Tubes. S Mahadevan. General Article Volume 19 Issue 5 May 2014 pp 395-405. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/019/05/0395-0405. Keywords.
International Nuclear Information System (INIS)
Henley, E.M.
1987-01-01
Nuclei are very useful for testing symmetries, and for studies of symmetry breaking. This thesis is illustrated for two improper space-time transformations, parity and time-reversal and for one internal symmetry: charge symmetry and independence. Recent progress and present interest is reviewed. 23 refs., 8 figs., 2 tabs
Symmetries and symmetry breaking beyond the electroweak theory
International Nuclear Information System (INIS)
Grojean, Ch.
1999-01-01
The Glashow-Salam-Weinberg theory describing electroweak interactions is one of the best successes of quantum field theory; it has passed all the experimental tests of particles physics with a high accuracy. However, this theory suffers from some deficiencies in the sense that some parameters, especially those involved in the generation of the mass of the elementary particles, are fixed to unnatural values. Moreover gravitation whose quantization cannot be achieved in ordinary quantum filed theory is hot taken into account. The aim of this PhD dissertation is to study some theories beyond the Standard Model and inspired by superstring theories. My endeavour has been to develop theoretical aspects of an effective dynamical description of one of the soltonic states of the strongly coupled strings. An important part of my results is also devoted to a more phenomenological analysis of the low energy effects of the symmetries that assure the coherence of the theories at high energy: these symmetries could explain the fermion mass hierarchy and could be directly observable in collider experiments. It is also shown how the geometrical properties of compactified spaces characterize the vacuum of string theory in a non-perturbative regime; such a vacuum can be used to construct a unified theory of gauge and gravitational interactions with a supersymmetry softy broken at a TcV scale. (author)
Contact symmetries and Hamiltonian thermodynamics
International Nuclear Information System (INIS)
Bravetti, A.; Lopez-Monsalvo, C.S.; Nettel, F.
2015-01-01
It has been shown that contact geometry is the proper framework underlying classical thermodynamics and that thermodynamic fluctuations are captured by an additional metric structure related to Fisher’s Information Matrix. In this work we analyse several unaddressed aspects about the application of contact and metric geometry to thermodynamics. We consider here the Thermodynamic Phase Space and start by investigating the role of gauge transformations and Legendre symmetries for metric contact manifolds and their significance in thermodynamics. Then we present a novel mathematical characterization of first order phase transitions as equilibrium processes on the Thermodynamic Phase Space for which the Legendre symmetry is broken. Moreover, we use contact Hamiltonian dynamics to represent thermodynamic processes in a way that resembles the classical Hamiltonian formulation of conservative mechanics and we show that the relevant Hamiltonian coincides with the irreversible entropy production along thermodynamic processes. Therefore, we use such property to give a geometric definition of thermodynamically admissible fluctuations according to the Second Law of thermodynamics. Finally, we show that the length of a curve describing a thermodynamic process measures its entropy production
Symmetry breaking and scalar bosons
International Nuclear Information System (INIS)
Gildener, E.; Weinberg, S.
1976-01-01
There are reasons to suspect that the spontaneous breakdown of the gauge symmetries of the observed weak and electromagnetic interactions may be produced by the vacuum expectation values of massless weakly coupled elementary scalar fields. A method is described for finding the broken-symmetry solutions of such theories even when they contain arbitrary numbers of scalar fields with unconstrained couplings. In any such theory, there should exist a number of heavy Higgs bosons, with masses comparable to the intermediate vector bosons, plus one light Higgs boson, or ''scalon'' with mass of order αG/sub F/sub 1/2/. The mass and couplings of the scalon are calculable in terms of other masses, even without knowing all the details of the theory. For an SU(2) direct-product U(1) model with arbitrary numbers of scalar isodoublets, the scalon mass is greater than 5.26 GeV; a likely value is 7--10 GeV. The production and decay of the scalon are briefly considered. Some comments are offered on the relation between the mass scales associated with the weak and strong interactions
Patterns of symmetry breaking in chiral QCD
Bolognesi, Stefano; Konishi, Kenichi; Shifman, Mikhail
2018-05-01
We consider S U (N ) Yang-Mills theory with massless chiral fermions in a complex representation of the gauge group. The main emphasis is on the so-called hybrid ψ χ η model. The possible patterns of realization of the continuous chiral flavor symmetry are discussed. We argue that the chiral symmetry is broken in conjunction with a dynamical Higgsing of the gauge group (complete or partial) by bifermion condensates. As a result a color-flavor locked symmetry is preserved. The 't Hooft anomaly matching proceeds via saturation of triangles by massless composite fermions or, in a mixed mode, i.e. also by the "weakly" coupled fermions associated with dynamical Abelianization, supplemented by a number of Nambu-Goldstone mesons. Gauge-singlet condensates are of the multifermion type and, though it cannot be excluded, the chiral symmetry realization via such gauge invariant condensates is more contrived (requires a number of four-fermion condensates simultaneously and, even so, problems remain) and less plausible. We conclude that in the model at hand, chiral flavor symmetry implies dynamical Higgsing by bifermion condensates.
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.
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.
Need for spontaneous breakdown of chiral symmetry
International Nuclear Information System (INIS)
Salomone, A.; Schechter, J.; Tudron, T.
1981-01-01
The question of whether the chiral symmetry of the theory of strong interactions (with massless quarks) is required to be spontaneously broken is examined in the framework of a previously discussed effective Lagrangian for quantum chromodynamics. The assumption that physical masses of the theory be finite leads in a very direct way to the necessity of spontaneous breakdown. This result holds for all N/sub F/> or =2, where N/sub F/ is the number of different flavors of light quarks. The atypical cases N/sub F/ = 1,2 are discussed separately
New particles and breaking the colour symmetry
International Nuclear Information System (INIS)
Krolikowski, W.
1975-01-01
In the framework of one-gluon-exchange static forces mediated by a colour octet or nonet of vector gluons, we discuss quark binding in coloured-meson states and its connection with breaking the colour symmetry. A possible identification of psi (3.1), psi(3.7) and the broad bump at 4.1 GeV with some coloured bound states of quarks and antiquarks is pointed out. This identification implies the existence of a second bump in the region of 5 GeV. The general conclusion of the paper is that the colour interpretation of the new particles may be true only if the colour symmetry is badly broken (provided the considered forces are relevant). (author)
Lepton flavor violation and seesaw symmetries
Energy Technology Data Exchange (ETDEWEB)
Aristizabal Sierra, D., E-mail: daristizabal@ulg.ac.be [Universite de Liege, IFPA, Department AGO (Belgium)
2013-03-15
When the standard model is extended with right-handed neutrinos the symmetries of the resulting Lagrangian are enlarged with a new global U(1){sub R} Abelian factor. In the context of minimal seesaw models we analyze the implications of a slightly broken U(1){sub R} symmetry on charged lepton flavor violating decays. We find, depending on the R-charge assignments, models where charged lepton flavor violating rates can be within measurable ranges. In particular, we show that in the resulting models due to the structure of the light neutrino mass matrix muon flavor violating decays are entirely determined by neutrino data (up to a normalization factor) and can be sizable in a wide right-handed neutrino mass range.
Broken Homes: Stable Risk, Changing Reasons, Changing Forms.
Sweetser, Dorrian Apple
1985-01-01
Cohort membership and two measures of social disadvantage were used as explanatory variables in analysis of the risk of growing up in a broken home and of the living arrangements of children with broken homes. The risk of a broken home by age 16 proved to be stable across cohorts and greater for those from disadvantaged homes. (Author/BL)
International Nuclear Information System (INIS)
Nilles, Hans Peter
2012-04-01
Discrete (family) symmetries might play an important role in models of elementary particle physics. We discuss the origin of such symmetries in the framework of consistent ultraviolet completions of the standard model in field and string theory. The symmetries can arise due to special geometrical properties of extra compact dimensions and the localization of fields in this geometrical landscape. We also comment on anomaly constraints for discrete symmetries.
Energy Technology Data Exchange (ETDEWEB)
Nilles, Hans Peter [Bonn Univ. (Germany). Bethe Center for Theoretical Physics; Bonn Univ. (Germany). Physikalisches Inst.; Ratz, Michael [Technische Univ. Muenchen, Garching (Germany). Physik-Department; Vaudrevange, Patrick K.S. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2012-04-15
Discrete (family) symmetries might play an important role in models of elementary particle physics. We discuss the origin of such symmetries in the framework of consistent ultraviolet completions of the standard model in field and string theory. The symmetries can arise due to special geometrical properties of extra compact dimensions and the localization of fields in this geometrical landscape. We also comment on anomaly constraints for discrete symmetries.
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.
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.
The fine-tuning problem in renormalized perturbation theory: Spontaneously-broken gauge models
International Nuclear Information System (INIS)
Foda, O.E.
1983-01-01
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. (orig.)
Symmetry, asymmetry and dissymmetry
International Nuclear Information System (INIS)
Wackenheim, A.; Zollner, G.
1987-01-01
The authors discuss the concept of symmetry and defect of symmetry in radiological imaging and recall the definition of asymmetry (congenital or constitutional) and dissymmetry (acquired). They then describe a rule designed for the cognitive method of automatic evaluation of shape recognition data and propose the use of reversal symmetry [fr
International Nuclear Information System (INIS)
Fuentes Cobas, L.E.; Font Hernandez, R.
1993-01-01
An analytical treatment of electrostatic and magnetostatic field symmetry, as a function of charge and current distribution symmetry, is proposed. The Newmann Principle, related to the cause-effect symmetry relation, is presented and applied to the characterization of simple configurations. (Author) 5 refs
Rehren, K. -H.
1996-01-01
Weak C* Hopf algebras can act as global symmetries in low-dimensional quantum field theories, when braid group statistics prevents group symmetries. Possibilities to construct field algebras with weak C* Hopf symmetry from a given theory of local observables are discussed.
Zheng, Guo-Qing
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 additional 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 obtained so far in any candidate compounds. We report 77Se nuclear magnetic resonance measurements which showed 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 (odd parity) superconductivity in this compound, but also serve to lay a foundation for the research of topological superconductivity (Ref.). We will also report the doping mechanism and superconductivity in Sn1-xInxTe.
No-go for tree-level R-symmetry breaking
Energy Technology Data Exchange (ETDEWEB)
Liu, Feihu [University of Electronic Science and Technology of China, School of Physical Electronics, Chengdu (China); Liu, Muyang [Sichuan University, Center for Theoretical Physics, College of Physical Science and Technology, Chengdu (China); Sun, Zheng [Sichuan University, Center for Theoretical Physics, College of Physical Science and Technology, Chengdu (China); Chinese Academy of Sciences, CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Beijing (China)
2017-11-15
We show that in gauge mediation models with tree-level R-symmetry breaking where supersymmetry and R-symmetries are broken by different fields, the gaugino mass either vanishes at one loop or finds a contribution from loop-level R-symmetry breaking. Thus tree-level R-symmetry breaking for phenomenology is either no-go or redundant in the simplest type of models. Including explicit messenger mass terms in the superpotential with a particular R-charge arrangement is helpful to bypass the no-go theorem, and the resulting gaugino mass is suppressed by the messenger mass scale. (orig.)
Performance improvements of symmetry-breaking reflector structures in nonimaging devices
Winston, Roland
2004-01-13
A structure and method for providing a broken symmetry reflector structure for a solar concentrator device. The component of the optical direction vector along the symmetry axis is conserved for all rays propagated through a translationally symmetric optical device. This quantity, referred to as the translational skew invariant, is conserved in rotationally symmetric optical systems. Performance limits for translationally symmetric nonimaging optical devices are derived from the distributions of the translational skew invariant for the optical source and for the target to which flux is to be transferred. A numerically optimized non-tracking solar concentrator utilizing symmetry-breaking reflector structures can overcome the performance limits associated with translational symmetry.
Raibert, M H
1986-03-14
Symmetry plays a key role in simplifying the control of legged robots and in giving them the ability to run and balance. The symmetries studied describe motion of the body and legs in terms of even and odd functions of time. A legged system running with these symmetries travels with a fixed forward speed and a stable upright posture. The symmetries used for controlling legged robots may help in elucidating the legged behavior of animals. Measurements of running in the cat and human show that the feet and body sometimes move as predicted by the even and odd symmetry functions.
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.
Investigation of spontaneously broken gauge theories
International Nuclear Information System (INIS)
Nagy, T.
1978-01-01
Spontaneously broken gauge theories (SBGT) with effects treated perturbatively are investigated. The general structure of SBGT is exhibited and gauge invariant renormalization program for practical calculations is set up. The proof of renormalizability of Lee and Zinn-Justin are extended to the problems of SBGT. A general semisimple compact gauge group is used. Arbitrary fermion and scalar multiplets are considered. The structure of the Lagrangian is discussed. The problem of quantization is described and the definition of the generating functionals of the Green functions and the Green functions themselves is given
Structure of pheomenological lagrangians for broken supersymmetry
International Nuclear Information System (INIS)
Uematsu, T.; Zachos, C.K.
1982-01-01
We consider the explicit connection between linear representations of supersymetry and the non-linear realizations associated with the generic effective lagrangians of the Volkov-Akulov type. We specify and illustrate a systematic approach for deriving the appropriate phenomenological lagrangian by transforming a pedagogical linear model, in which supersymmetry is broken at the tree level, into its corresponding non-linear lagrangian, in close analogy to the linear sigma model of pion dynamics. We discuss the significance and some properties of such phenomenological lagrangians. (orig.)
Neutrino mass and mixing with discrete symmetry
International Nuclear Information System (INIS)
King, Stephen F; Luhn, Christoph
2013-01-01
This is a review paper 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 see-saw 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 mechanisms for flavon vacuum alignment and different model building strategies that have been proposed to generate the reactor angle. We then briefly review grand unified theories (GUTs) and how they may be combined with discrete family symmetry to describe all quark and lepton masses and mixing. Finally, we discuss three model examples which combine an SU(5) GUT with the discrete family symmetries A 4 , S 4 and Δ(96). (review article)
Electroweak symmetry breaking: Higgs/whatever
International Nuclear Information System (INIS)
Chanowitz, M.S.
1990-01-01
In these two lectures the author discusses electroweak symmetry breaking from a general perspective, stressing properties that are model independent and follow just from the assumption that the electroweak interactions are described by a spontaneously broken gauge theory. This means he assumes the Higgs mechanism though not necessarily the existence of Higgs bosons. The first lecture presents the general framework of a spontaneously broken gauge theory: (1) the Higgs mechanism sui generis, with or without Higgs boson(s) and (2) the implications of symmetry and unitarity for the mass scale and interaction strength of the new physics that the Higgs mechanism requires. In addition he reviews a softer theoretical argument based on the naturalness problem which leads to a prejudice against Higgs bosons unless they are supersymmetric. This is a prejudice, not a theorem, and it could be overturned in the future by a clever new idea. In the second lecture he illustrates the general framework by reviewing some specific models: (1) the Weinberg-Salam model of the Higgs sector; (2) the minimal supersymmetric extension of the Weinberg-Salam model; and (3) technicolor as an example of the Higgs mechanism without Higgs bosons. He concludes the second lecture with a discussion of strong WW scattering that must occur if L SB lives above 1 TeV. In particular he describes some of the experimental signals and backgrounds at the SSC. 57 refs., 12 figs
Invariant renormalization method for nonlinear realizations of dynamical symmetries
International Nuclear Information System (INIS)
Kazakov, D.I.; Pervushin, V.N.; Pushkin, S.V.
1977-01-01
The structure of ultraviolet divergences is investigated for the field theoretical models with nonlinear realization of the arbitrary semisimple Lie group, with spontaneously broken symmetry of vacuum. An invariant formulation of the background field method of renormalization is proposed which gives the manifest invariant counterterms off mass shell. A simple algorithm for construction of counterterms is developed. It is based on invariants of the group of dynamical symmetry in terms of the Cartan forms. The results of one-loop and two-loop calculations are reported
Applications of flavor symmetry to the phenomenology of elementary particles
International Nuclear Information System (INIS)
Kaeding, T.A.
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
Strong evidence for spontaneous chiral symmetry breaking in (quenched) QCD
International Nuclear Information System (INIS)
Barbour, I.M.; Gibbs, P.; Schierholz, G.; Teper, M.; Gilchrist, J.P.; Schneider, H.
1983-09-01
We calculate the chiral condensate for all quark masses using Kogut-Susskind fermions in lattice-regularized quenched QCD. The large volume behaviour of at small quark masses demonstrates that the explicit U(1) chiral symmetry is spontaneously broken. We perform the calculation for β = 5.1 to 5.9 and find very good continuum renormalization group behaviour. We infer that the spontaneous breaking we observe belongs to continuum QCD. This constitutes the first unambiguous demonstration of spontaneous chiral symmetry breaking in continuum quenched QCD. (orig.)
Discrete quark-lepton symmetry need not pose a cosmological domain wall problem
International Nuclear Information System (INIS)
Lew, H.; Volkas, R.R.
1992-01-01
Quarks and leptons may be related to each other through a spontaneously broken discrete symmetry. Models with acceptable and interesting collider phenomenology have been constructed which incorporate this idea. However, the standard Hot Big Bang model of cosmology is generally considered to eschew spontaneously broken discrete symmetries because they often lead to the formation of unacceptably massive domain walls. It is pointed out that there are a number of plausible quark-lepton symmetric models in nature which do not produce cosmologically troublesome domain walls. 30 refs
Symmetry and symmetry breaking in quantum mechanics
International Nuclear Information System (INIS)
Chomaz, Philippe
1998-01-01
In the world of infinitely small, the world of atoms, nuclei and particles, the quantum mechanics enforces its laws. The discovery of Quanta, this unbelievable castration of the Possible in grains of matter and radiation, in discrete energy levels compels us of thinking the Single to comprehend the Universal. Quantum Numbers, magic Numbers and Numbers sign the wave. The matter is vibration. To describe the music of the world one needs keys, measures, notes, rules and partition: one needs quantum mechanics. The particles reduce themselves not in material points as the scholars of the past centuries thought, but they must be conceived throughout the space, in the accomplishment of shapes of volumes. When Einstein asked himself whether God plays dice, there was no doubt among its contemporaries that if He exists He is a geometer. In a Nature reduced to Geometry, the symmetries assume their role in servicing the Harmony. The symmetries allow ordering the energy levels to make them understandable. They impose there geometrical rules to the matter waves, giving them properties which sometimes astonish us. Hidden symmetries, internal symmetries and newly conceived symmetries have to be adopted subsequently to the observation of some order in this world of Quanta. In turn, the symmetries provide new observables which open new spaces of observation
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.
Mass generation and chiral symmetry breaking by pseudoparticles
International Nuclear Information System (INIS)
Hietarinta, J.; Palmer, W.F.; Pinsky, S.S.
1978-01-01
Massless QCD is studied with regard to mass generation and chiral SU(N/sub f/) symmetry breaking from pseudoparticle effects. While mass is generated when there is only one massless quark, and chiral U(1) is always broken, no rigorous indication of the breaking of chiral SU(N/sub f/) and mass generation is seen when there are more than one massless quarks in the original theory
Heavy quark condensates from dynamically borken flavour symmetry
International Nuclear Information System (INIS)
Elliott, T.; King, S.F.
1992-01-01
We study the dynamics of top quark condensation induced by gauge interactions resulting from a broken flavour symmetry. The gap equation in dressed ladder approximation is solved numerically to obtain directly the top quark mass. The new high energy dynamics reduces the prediction of m t somewhat, but the usual problems of m t being too large and fine tuning remain. In order to solve these problems we extend our discussion to include fourth generation quark condensates. (orig.)
Vacuum polarization and dynamical chiral symmetry breaking in quantum electrodynamics
International Nuclear Information System (INIS)
Gusynin, V.P.
1989-01-01
The Schwinger-Dyson equation in the ladder approximation is considered for the fermion mass function taking into account the vacuum polarization effects. It is shown that even in the 'zero-charge' situation there exists, at rather large coupling constant (α>α c >0), a solution with spontaneously broken chiral symmetry. The existence of the local limit in the model concerned is discussed. 30 refs.; 1 fig
Dynamical symmetry breaking with hypercolour and high colour representations
International Nuclear Information System (INIS)
Zoupanos, G.
1985-01-01
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. (author)
International Nuclear Information System (INIS)
Mainzer, K.
1988-01-01
Symmetry, disymmetry, chirality etc. are well-known topics in chemistry. But they cannot only be found on the molecular level of matter. Atoms and elementary particles in physics are also characterized by particular symmetry groups. Even living organisms and populations on the macroscopic level have functional properties of symmetry. The whole physical, chemical, and biological evolution seems to be regulated by the emergence of new symmetries and the breaking down of old ones. One is reminded of Heisenberg's famous statement: 'Die letzte Wurzel der Erscheinungen ist also nicht die Materie, sondern das mathematische Gesetz, die Symmetrie, die mathematische Form' (Wandlungen in den Grundlagen der Naturwissenschaften, 1959). Historically the belief in symmetry and simplicity of nature has a long philosophical tradition from the Pythagoreans, Plato and Greek astronomers to Kepler and modern scientists. Today, 'symmetries in nature' is a common topic of mathematics, physics, chemistry, and biology. A lot of Nobel prizes were given in honour of inquiries concerning symmetries in nature. The fascination of symmetries is not only motivated by science, but by art and religion too. Therefore 'symmetris in nature' is an interdisciplinary topic which may help to overcome C.P. Snow's 'Two Cultures' of natural sciences and humanities. (author) 17 refs., 21 figs
Energy Technology Data Exchange (ETDEWEB)
Mainzer, K
1988-05-01
Symmetry, disymmetry, chirality etc. are well-known topics in chemistry. But they cannot only be found on the molecular level of matter. Atoms and elementary particles in physics are also characterized by particular symmetry groups. Even living organisms and populations on the macroscopic level have functional properties of symmetry. The whole physical, chemical, and biological evolution seems to be regulated by the emergence of new symmetries and the breaking down of old ones. One is reminded of Heisenberg's famous statement: 'Die letzte Wurzel der Erscheinungen ist also nicht die Materie, sondern das mathematische Gesetz, die Symmetrie, die mathematische Form' (Wandlungen in den Grundlagen der Naturwissenschaften, 1959). Historically the belief in symmetry and simplicity of nature has a long philosophical tradition from the Pythagoreans, Plato and Greek astronomers to Kepler and modern scientists. Today, 'symmetries in nature' is a common topic of mathematics, physics, chemistry, and biology. A lot of Nobel prizes were given in honour of inquiries concerning symmetries in nature. The fascination of symmetries is not only motivated by science, but by art and religion too. Therefore 'symmetris in nature' is an interdisciplinary topic which may help to overcome C.P. Snow's 'Two Cultures' of natural sciences and humanities. (author) 17 refs., 21 figs.
Energy Technology Data Exchange (ETDEWEB)
Miller, G.A. [Department of Physics, University of Washington, Seattle (United States); Kolck, U. van [Department of Physics, University of Arizona, Tucson (United States)
2003-06-01
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 the down quark has a negative charge of -1/3. If charge symmetry was exact, the proton and the neutron would have the same mass and they would both be electrically neutral. This is because the proton is made of two up quarks and a down quark, while the neutron comprises two downs and an up. Replacing up quarks with down quarks, and vice versa, therefore transforms a proton into a neutron. Charge-symmetry breaking causes the neutron to be about 0.1% heavier than the proton because the down quark is slightly heavier than the up quark. Physicists had already elucidated certain aspects of charge-symmetry breaking, but our spirits were raised greatly when we heard of the recent work of Allena Opper of Ohio University in the US and co-workers at the TRIUMF laboratory in British Columbia, Canada. Her team has been trying to observe a small charge-symmetry-breaking effect for several years, using neutron beams at the TRIUMF accelerator. The researchers studied the
CP nonconservation in dynamically broken gauge theories
International Nuclear Information System (INIS)
Lane, K.
1981-01-01
The recent proposal of Eichten, Lane, and Preskill for CP nonconservation in electroweak gauge theories with dynamical symmetry breaking is reviewed. Through the alignment of the vacuum with the explicit chiral symmetry breaking Hamiltonian, these theories provide a natural way to understand the dynamical origin of CP nonconservation. Special attention is paid to the problem of strong CP violation. Even through all vacuum angles are zero, this problem is not automatically avoided. In the absence of strong CP violation, the neutron electric dipole moment is expected to be 10 -24 -10 -26 e-cm. A new class of models is proposed in which both strong CP violation and large /ΔS/ = 2 effects may be avoided. In these models, /ΔC/ = 2 processes such as D/sup o/ D/sup -o/ mixing may be large enough to observe
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. Copyright © 2014 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.
Zhang, Zhiwang; Tian, Ye; Cheng, Ying; Liu, Xiaojun; Christensen, Johan
2017-12-01
Topologically protected wave engineering in artificially structured media resides at the frontier of ongoing metamaterials research, which is inspired by quantum mechanics. Acoustic analogs of electronic topological insulators have recently led to a wealth of new opportunities in manipulating sound propagation by means of robust edge mode excitations through analogies drawn to exotic quantum states. A variety of artificial acoustic systems hosting topological edge states have been proposed analogous to the quantum Hall effect, topological insulators, and Floquet topological insulators in electronic systems. However, those systems were characterized by a fixed geometry and a very narrow frequency response, which severely hinders the exploration and design of useful applications. Here we establish acoustic multipolar pseudospin states as an engineering degree of freedom in time-reversal invariant flow-free phononic crystals and develop reconfigurable topological insulators through rotation of their meta-atoms and reshaping of the metamolecules. Specifically, we show how rotation forms man-made snowflakelike molecules, whose topological phase mimics pseudospin-down (pseudospin-up) dipolar and quadrupolar states, which are responsible for a plethora of robust edge confined properties and topological controlled refraction disobeying Snell's law.
Noise-induced drift in systems with broken symmetry and classical routes to superconductivity
International Nuclear Information System (INIS)
Shapiro, V.E.
1994-01-01
We discuss concepts and mechanisms of particle motion in a variety of conditions of asymmetry towards spatial inversion that suggest an idea for the possibility of persistent currents within classical statistical considerations. We expose misapplications of Gibbs statistics and the Langevin approach and show that the idea does not contradict general principles. It gains support from the classical mechanism of capillary wave instability and keeps within the detailed balance and fluctuation-dissipation theorems. (author). 7 refs., 2 figs
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...
Cho, J.; Kim, N.H.; Lee, S.; Kim, J.S.; Lavrijsen, R.; Solignac, A.M.P.; Yin, Y.; Han, D.; Hoof, N.J.J.; Swagten, H.J.M.; Koopmans, B.; You, C.-H.
In magnetic multilayer systems, a large spin-orbit coupling at the interface between heavy metals and ferromagnets can lead to intriguing phenomena such as the perpendicular magnetic anisotropy, the spin Hall effect, the Rashba effect, and especially the interfacial Dzyaloshinskii–Moriya (IDM)
Kim, Sung-Cheol; Wunsch, Benjamin H; Hu, Huan; Smith, Joshua T; Austin, Robert H; Stolovitzky, Gustavo
2017-06-27
Deterministic lateral displacement (DLD) is a technique for size fractionation of particles in continuous flow that has shown great potential for biological applications. Several theoretical models have been proposed, but experimental evidence has demonstrated that a rich class of intermediate migration behavior exists, which is not predicted. We present a unified theoretical framework to infer the path of particles in the whole array on the basis of trajectories in a unit cell. This framework explains many of the unexpected particle trajectories reported and can be used to design arrays for even nanoscale particle fractionation. We performed experiments that verify these predictions and used our model to develop a condenser array that achieves full particle separation with a single fluidic input.
Structural versus electronic distortions of symmetry-broken IrTe$_2$
Kim, Hyo Sung; Kim, Tae-Hwan; Yang, Junjie; Cheong, Sang-Wook; Yeom, Han Woong
2014-01-01
We investigate atomic and electronic structures of the intriguing low temperature phase of IrTe2 using high-resolution scanning tunneling microscopy and spectroscopy. We confirm various stripe superstructures such as $\\times$3, $\\times$5, and $\\times$8. The strong vertical and lateral distortions of the lattice for the stripe structures are observed in agreement with recent calculations. The spatial modulations of electronic density of states are clearly identified as separated from the struc...
Broken-symmetry ground states in .nu.=2 bilayer quantum Hall systems
Czech Academy of Sciences Publication Activity Database
MacDonald, A. H.; Rajaraman, R. U.; Jungwirth, Tomáš
1999-01-01
Roč. 60, č. 12 (1999), s. 8817-8826 ISSN 0163-1829 R&D Projects: GA ČR GA202/98/0085; GA MŠk ME 104 Institutional research plan: CEZ:AV0Z1010914 Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.008, year: 1999
Control the polarization state of light with symmetry-broken metallic metastructures
International Nuclear Information System (INIS)
Xiong, Xiang; Jiang, Shang-Chi; Hu, Yuan-Sheng; Hu, Yu-Hui; Wang, Zheng-Han; Peng, Ru-Wen; Wang, Mu
2015-01-01
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
Odd-parity magnetoresistance in pyrochlore iridate thin films with broken time-reversal symmetry
Fujita, T. C.; Kozuka, Y.; Uchida, M.; Tsukazaki, A.; Arima, T.; Kawasaki, M.
2015-01-01
A new class of materials termed topological insulators have been intensively investigated due to their unique Dirac surface state carrying dissipationless edge spin currents. Recently, it has been theoretically proposed that the three dimensional analogue of this type of band structure, the Weyl Semimetal phase, is materialized in pyrochlore oxides with strong spin-orbit coupling, accompanied by all-in-all-out spin ordering. Here, we report on the fabrication and magnetotransport of Eu2Ir2O7 single crystalline thin films. We reveal that one of the two degenerate all-in-all-out domain structures, which are connected by time-reversal operation, can be selectively formed by the polarity of the cooling magnetic field. Once formed, the domain is robust against an oppositely polarised magnetic field, as evidenced by an unusual odd field dependent term in the magnetoresistance and an anomalous term in the Hall resistance. Our findings pave the way for exploring the predicted novel quantum transport phenomenon at the surfaces/interfaces or magnetic domain walls of pyrochlore iridates. PMID:25959576
Hierarchy stability for spontaneously broken theories
Energy Technology Data Exchange (ETDEWEB)
Galvan, J B; Perez-Mercader, J; Sanchez, F J
1987-04-16
By using Weisberger's method for the integration of heavy degrees of freedom in multiscale theories, we show that tree level hierarchies are not destabilized byquantum corrections in a two-scale, two scalar field theory model where the heavy sector undergoes spontaneous symmetry breaking. We see explicitly the role played by the one-loop heavy log corrections to the effective parameters in maintaining the original tree level hierarchy and in keeping the theory free of hierarchy problems.
Hierarchy stability for spontaneously broken theories
International Nuclear Information System (INIS)
Galvan, J.B.; Perez-Mercader, J.; Sanchez, F.J.
1987-01-01
By using Weisberger's method for the integration of heavy degrees of freedom in multiscale theories, we show that tree level hierarchies are not destabilized byquantum corrections in a two-scale, two scalar field theory model where the heavy sector undergoes spontaneous symmetry breaking. We see explicitly the role played by the one-loop heavy log corrections to the effective parameters in maintaining the original tree level hierarchy and in keeping the theory free of hierarchy problems. (orig.)
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.
From physical symmetries to emergent gauge symmetries
International Nuclear Information System (INIS)
Barceló, Carlos; Carballo-Rubio, Raúl; 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 gravity program, such as the Weinberg-Witten theorem, are discussed.
Harris, A. Brooks
2006-01-01
This paper represents a detailed instruction manual for constructing the Landau expansion for magnetoelectric coupling in incommensurate ferroelectric magnets. The first step is to describe the magnetic ordering in terms of symmetry adapted coordinates which serve as complex valued magnetic order parameters whose transformation properties are displayed. In so doing we use the previously proposed technique to exploit inversion symmetry, since this symmetry had been universally overlooked. Havi...
Effective action of softly broken supersymmetric theories
International Nuclear Information System (INIS)
Groot Nibbelink, S.; Nyawelo, T.S
2006-12-01
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. (author)
Spontaneously broken extended supersymmetry: Full superfield formulation
International Nuclear Information System (INIS)
Kandelakis, E.S.
1984-01-01
The superfield description, given by Samuel and Wess, of the non-linear Akulov-Volkov realization of (broken) supersymmetry, is generalized for the interesting cases of N=2 and 4 extended supersymmetry. The generalization, in terms of the full-superfield formulation, is straightforward. For the proof we first define the corresponding THETA-algebras; we then present explicitly many of the calculations. The schematic explanation makes the generalization manifest. We perform, for N=2, the coupling of the A-V field to standard-matter, in the way introduced by S-W, and schematically we make manifest the generalization for every N. The importance of our results consists in a complete, calculable description of the A-V fields (goldstinos) and of their interactions, easily applied to the tasks of today's phenomenology. (orig.) [de
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.)
Approximate and renormgroup symmetries
International Nuclear Information System (INIS)
Ibragimov, Nail H.; Kovalev, Vladimir F.
2009-01-01
''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.)
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.
Holographic theories of electroweak symmetry breaking without a Higgs Boson
International Nuclear Information System (INIS)
Burdman, Gustavo; Nomura, Yasunori
2003-01-01
Recently, realistic theories of electroweak symmetry breaking have been constructed in which the electroweak symmetry is broken by boundary conditions imposed at a boundary of higher dimensional spacetime. These theories have equivalent 4D dual descriptions, in which the electroweak symmetry is dynamically broken by non-trivial infrared dynamics of some gauge interaction, whose gauge coupling (tilde g) and size N satisfy (tilde g) 2 N ∼> 16π 2 . Such theories allow one to calculate electroweak radiative corrections, including the oblique parameters S, T and U, as long as (tilde g) 2 N/16π 2 and N are sufficiently larger than unity. We study how the duality between the 4D and 5D theories manifests itself in the computation of various physical quantities. In particular, we calculate the electroweak oblique parameters in a warped 5D theory where the electroweak symmetry is broken by boundary conditions at the infrared brane. We show that the value of S obtained in the minimal theory exceeds the experimental bound if the theory is in a weakly coupled regime. This requires either an extension of the minimal model or departure from weak coupling. A particularly interesting scenario is obtained if the gauge couplings in the 5D theory take the largest possible values--the value suggested by naive dimensional analysis. We argue that such a theory can provide a potentially consistent picture for dynamical electroweak symmetry breaking: corrections to the electroweak observables are sufficiently small while realistic fermion masses are obtained without conflicting with bounds from flavor violation. The theory contains only the standard model quarks, leptons and gauge bosons below ≅2 TeV, except for a possible light scalar associated with the radius of the extra dimension. At ≅2 TeV increasingly broad string resonances appear. An analysis of top-quark phenomenology and flavor violation is also presented, which is applicable to both the weakly-coupled and strongly
Logotherapy Counseling to Improve Acceptance of Broken Home Child
Erlangga, Erwin
2017-01-01
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 c...
Anomaly-free gauged R-symmetry in local supersymmetry
International Nuclear Information System (INIS)
Chamseddine, A.H.; Dreiner, H.
1996-01-01
We discuss local R-symmetry as a potentially powerful new model building tool. We first review and clarify that a U(1) R-symmetry can only be gauged in local and not in global supersymmetry. We determine the anomaly-cancellation conditions for the gauged R-symmetry. For the standard superpotential these equations have no solution, independently of how many Standard Model singlets are added to the model. There is also no solution when we increase the number of families and the number of pairs of Higgs doublets. When the Green-Schwarz mechanism is employed to cancel the anomalies, solutions only exist for a large number of singlets. We find many anomaly-free family-independent models with an extra SU(3) c octet chiral superfield. We consider in detail the conditions for an anomaly-free family-dependent U(1) R and find solutions with one, two, three and four extra singlets. Only with three and four extra singlets do we naturally obtain sfermion masses of the order of the weak scale. For these solutions we consider the spontaneous breaking of supersymmetry and the R-symmetry in the context of local supersymmetry. In general the U(1) R gauge group is broken at or close to the Planck scale. We consider the effects of the R-symmetry on baryon- and lepton-number violation in supersymmetry. There is no logical connection between a conserved R-symmetry and a conserved R-parity. For conserved R-symmetry we have models for all possibilities of conserved or broken R-parity. Most models predict dominant effects which could be observed at HERA. (orig.)
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
Model for predicting the frequency of broken rails
Directory of Open Access Journals (Sweden)
S. Vesković
2012-04-01
Full Text Available Broken rails can cause train delays, trains cancelations and, unfortunately, they are common causes of accidents. This affects planning of a resources, budget and organization of railway track maintenance. Planning of railway track maintenance cannot be done without an estimation of number of rails that will be replaced due to the broken rail incidents. There are many factors that influence broken rails and the most common are: rail age, annual gross tonnage, degree of curve and temperature in the time of breakage. The fuzzy logic model uses acquired data as input variables to predict the frequency of broken rails for the certain rail types on some Sections.
International Nuclear Information System (INIS)
Haxton, W.C.
1988-01-01
I discuss a number of the themes of the Symmetries and Spin session of the 8th International Symposium on High Energy Spin Physics: parity nonconservation, CP/T nonconservation, and tests of charge symmetry and charge independence. 28 refs., 1 fig
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.
Quantum symmetry for pedestrians
International Nuclear Information System (INIS)
Mack, G.; Schomerus, V.
1992-03-01
Symmetries more general than groups are possible in quantum therory. Quantum symmetries in the narrow sense are compatible with braid statistics. They are theoretically consistent much as supersymmetry is, and they could lead to degenerate multiplets of excitations with fractional spin in thin films. (orig.)
Wigner's Symmetry Representation Theorem
Indian Academy of Sciences (India)
IAS Admin
At the Heart of Quantum Field Theory! Aritra Kr. ... principle of symmetry was not held as something very fundamental ... principle of local symmetry: the laws of physics are invariant un- .... Next, we would show that different coefficients of a state ...
Charged fluids with symmetries
Indian Academy of Sciences (India)
It is possible to introduce many types of symmetries on the manifold which restrict the ... metric tensor field and generate constants of the motion along null geodesics .... In this analysis we have studied the role of symmetries for charged perfect ...
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.
Chiral symmetry restoration and quasi-elastic electron-nucleus scattering
International Nuclear Information System (INIS)
Henley, E.M.; Krein, G.
1989-01-01
Chiral symmetry is known to be an important concept in hadronic interactions. It holds in QCD, but is known to be broken at low energies. It is therefore useful to study chiral symmetry and its breaking together with its consequences in nuclear physics. It is the latter phenomena we consider here. It is difficult to study nonperturbative QCD at low energies and models are needed. The Nambu-Jona-Lasinio (NJL) model fits this category; it incorporates chiral symmetry and its breaking, and allows one to study its effects in nucleons and nuclei. In particular, the constituent quark mass varies with density (ρ) and temperature (T). At high ρ and T chiral symmetry is restored. It is the ρ dependence which yields important effects in electron scattering due to partial restoration of chiral symmetry in nuclei. We begin with the NJL model with a small chiral symmetry breaking
Symmetry aspects in emergent quantum mechanics
Elze, Hans-Thomas
2009-06-01
We discuss an explicit realization of the dissipative dynamics anticipated in the proof of 't Hooft's existence theorem, which states that 'For any quantum system there exists at least one deterministic model that reproduces all its dynamics after prequantization'. - There is an energy-parity symmetry hidden in the Liouville equation, which mimics the Kaplan-Sundrum protective symmetry for the cosmological constant. This symmetry may be broken by the coarse-graining inherent in physics at scales much larger than the Planck length. We correspondingly modify classical ensemble theory by incorporating dissipative fluctuations (information loss) - which are caused by discrete spacetime continually 'measuring' matter. In this way, aspects of quantum mechanics, such as the von Neumann equation, including a Lindblad term, arise dynamically and expectations of observables agree with the Born rule. However, the resulting quantum coherence is accompanied by an intrinsic decoherence and continuous localization mechanism. Our proposal leads towards a theory that is linear and local at the quantum mechanical level, but the relation to the underlying classical degrees of freedom is nonlocal.
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
Conformal Symmetry as a Template for QCD
Energy Technology Data Exchange (ETDEWEB)
Brodsky, S
2004-08-04
Conformal symmetry is broken in physical QCD; nevertheless, one can use conformal symmetry as a template, systematically correcting for its nonzero {beta} function as well as higher-twist effects. For example, commensurate scale relations which relate QCD observables to each other, such as the generalized Crewther relation, have no renormalization scale or scheme ambiguity and retain a convergent perturbative structure which reflects the underlying conformal symmetry of the classical theory. The ''conformal correspondence principle'' also dictates the form of the expansion basis for hadronic distribution amplitudes. The AdS/CFT correspondence connecting superstring theory to superconformal gauge theory has important implications for hadron phenomenology in the conformal limit, including an all-orders demonstration of counting rules for hard exclusive processes as well as determining essential aspects of hadronic light-front wavefunctions. Theoretical and phenomenological evidence is now accumulating that QCD couplings based on physical observables such as {tau} decay become constant at small virtuality; i.e., effective charges develop an infrared fixed point in contradiction to the usual assumption of singular growth in the infrared. The near-constant behavior of effective couplings also suggests that QCD can be approximated as a conformal theory even at relatively small momentum transfer. The importance of using an analytic effective charge such as the pinch scheme for unifying the electroweak and strong couplings and forces is also emphasized.
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.
Conformal Symmetry as a Template for QCD
International Nuclear Information System (INIS)
Brodsky, S
2004-01-01
Conformal symmetry is broken in physical QCD; nevertheless, one can use conformal symmetry as a template, systematically correcting for its nonzero β function as well as higher-twist effects. For example, commensurate scale relations which relate QCD observables to each other, such as the generalized Crewther relation, have no renormalization scale or scheme ambiguity and retain a convergent perturbative structure which reflects the underlying conformal symmetry of the classical theory. The ''conformal correspondence principle'' also dictates the form of the expansion basis for hadronic distribution amplitudes. The AdS/CFT correspondence connecting superstring theory to superconformal gauge theory has important implications for hadron phenomenology in the conformal limit, including an all-orders demonstration of counting rules for hard exclusive processes as well as determining essential aspects of hadronic light-front wavefunctions. Theoretical and phenomenological evidence is now accumulating that QCD couplings based on physical observables such as τ decay become constant at small virtuality; i.e., effective charges develop an infrared fixed point in contradiction to the usual assumption of singular growth in the infrared. The near-constant behavior of effective couplings also suggests that QCD can be approximated as a conformal theory even at relatively small momentum transfer. The importance of using an analytic effective charge such as the pinch scheme for unifying the electroweak and strong couplings and forces is also emphasized
Symmetry and symmetry breaking in modern physics
International Nuclear Information System (INIS)
Barone, M; Theophilou, A K
2008-01-01
In modern physics, the theory of symmetry, i.e. group theory, is a basic tool for understanding and formulating the fundamental principles of Physics, like Relativity, Quantum Mechanics and Particle Physics. In this work we focus on the relation between Mathematics, Physics and objective reality
SO(8) fermion dynamical symmetry and strongly correlated quantum Hall states in monolayer graphene
Wu, Lian-Ao; Murphy, Matthew; Guidry, Mike
2017-03-01
A formalism is presented for treating strongly correlated graphene quantum Hall states in terms of an SO(8) fermion dynamical symmetry that includes pairing as well as particle-hole generators. The graphene SO(8) algebra is isomorphic to an SO(8) algebra that has found broad application in nuclear physics, albeit with physically very different generators, and exhibits a strong formal similarity to SU(4) symmetries that have been proposed to describe high-temperature superconductors. The well-known SU(4) symmetry of quantum Hall ferromagnetism for single-layer graphene is recovered as one subgroup of SO(8), but the dynamical symmetry structure associated with the full set of SO(8) subgroup chains extends quantum Hall ferromagnetism and allows analytical many-body solutions for a rich set of collective states exhibiting spontaneously broken symmetry that may be important for the low-energy physics of graphene in strong magnetic fields. The SO(8) symmetry permits a natural definition of generalized coherent states that correspond to symmetry-constrained Hartree-Fock-Bogoliubov solutions, or equivalently a microscopically derived Ginzburg-Landau formalism, exhibiting the interplay between competing spontaneously broken symmetries in determining the ground state.
Wess-Zumino model as linear σ-model of spontaneously broken conformal and OSp (1,4)-supersymmetries
International Nuclear Information System (INIS)
Ivanov, E.A.
1979-01-01
The massless Wess-Zumino model is shown to exhibit the spontaneous breaking of global conformal and orthosymplectic supersymmetries on account of the Fubini-type classical solutions to the equations of motion. The group structure of spontaneously broken phase is studied and its particle spectrum is analyzed. The little group of the ground state is found to be the graded subgroup OSp(1,4) of the conformal supergroup. The symmetry with respect to another OSp(1,4) subgroup (OSp(1,4))Ois broken to (2,3)-symmetry with emergence of massive Goldstone fermion. The superfield Weyl transformation is defined and with its help the model action is rewritten in terms of superspace OSp(1,4)/O(1,3), spinorial extension of anti de Sitter space. In such a representation the spontaneously broken phase admits the standard σ-model interpretation. We also construct the OSp(1,4)-analog of the massive Wess-Zumino model and examine its vacuum structure. An effect of the spontaneous breaking of P- and CP-parities with the strength related to anti de Sitter radius is found
Nonabelian family symmetry and the origin of fermion masses and mixing angles
International Nuclear Information System (INIS)
Soldate, M.; Reno, M.H.; Hill, C.T.
1986-01-01
The origin of fermion masses and mixing angles is studied in a class of gauged family-symmetry models broken by elementary Higgs scalars at ≅10 3 TeV. It is found that large hierarchies among fermion masses can be produced more naturally in a model with four generations rather than three. (orig.)
International Nuclear Information System (INIS)
Dudal, David; Verschelde, Henri; Rodino Lemes, Vitor Emanuel; Sarandy, Marcelo S.; Sorella, Silvio Paolo; Picariello, Marco
2002-01-01
The existence of a SL(2;R) symmetry is discussed in SU(N) Yang-Mills in the maximal abelian gauge. This symmetry, also present in the Landau and Curci-Ferrari gauge, ensures the absence of tachyons in the maximal abelian gauge. In all these gauges, SL(2;R) turns out to be dynamically broken by ghost condensates. (author)
Effects of rotational symmetry breaking in polymer-coated nanopores
Osmanović, D.; Kerr-Winter, M.; Eccleston, R. C.; Hoogenboom, B. W.; Ford, I. J.
2015-01-01
The statistical theory of polymers tethered around the inner surface of a cylindrical channel has traditionally employed the assumption that the equilibrium density of the polymers is independent of the azimuthal coordinate. However, simulations have shown that this rotational symmetry can be broken when there are attractive interactions between the polymers. We investigate the phases that emerge in these circumstances, and we quantify the effect of the symmetry assumption on the phase behavior of the system. In the absence of this assumption, one can observe large differences in the equilibrium densities between the rotationally symmetric case and the non-rotationally symmetric case. A simple analytical model is developed that illustrates the driving thermodynamic forces responsible for this symmetry breaking. Our results have implications for the current understanding of the behavior of polymers in cylindrical nanopores.
Effects of rotational symmetry breaking in polymer-coated nanopores
Energy Technology Data Exchange (ETDEWEB)
Osmanović, D.; Hoogenboom, B. W.; Ford, I. J. [London Centre for Nanotechnology (LCN) and Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Kerr-Winter, M.; Eccleston, R. C. [Centre for Mathematics, Physics and Engineering in the Life Sciences and Experimental Biology, University College London, Gower Street, London WC1E 6BT (United Kingdom)
2015-01-21
The statistical theory of polymers tethered around the inner surface of a cylindrical channel has traditionally employed the assumption that the equilibrium density of the polymers is independent of the azimuthal coordinate. However, simulations have shown that this rotational symmetry can be broken when there are attractive interactions between the polymers. We investigate the phases that emerge in these circumstances, and we quantify the effect of the symmetry assumption on the phase behavior of the system. In the absence of this assumption, one can observe large differences in the equilibrium densities between the rotationally symmetric case and the non-rotationally symmetric case. A simple analytical model is developed that illustrates the driving thermodynamic forces responsible for this symmetry breaking. Our results have implications for the current understanding of the behavior of polymers in cylindrical nanopores.
Spontaneous symmetry breaking in the $S_3$-symmetric scalar sector
Emmanuel-Costa, D.; Osland, P.; Rebelo, M.N.
2016-02-23
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.
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...
Imprints of supersymmetry in the Lorentz-symmetry breaking of Gauge Theories
Energy Technology Data Exchange (ETDEWEB)
Belich, H [Universidade Federal do Espirito Santo (UFES), Vitoria, ES (Brazil); Dias, G S; Leal, F J.L. [Instituto Federal de Educacao, Ciencia e Tecnologia do Espirito Santo (IFES), Vitoria, ES (Brazil); Durand, L G; Helayel-Neto, Jose Abdalla; Spalenza, W [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Grupo de Fisica Teorica Jose Leite Lopes (GFT-JLL), Petropolis, RJ (Brazil)
2011-07-01
Full text: The breaking of Lorentz symmetry that may take place at very high energies opens up a venue for the discussion of the interplay between the violations of supersymmetry and relativistic symmetry. Recently, there have appeared in the literature models which propose a residual (non-relativistic) supersymmetry after Lorentz symmetry has been broken in a Horava gravity scenario. We here propose an N=1-supersymmetric Abelian gauge model which realises the breaking of Lorentz invariance by means of a CPT-even term. Our attempt assumes the point of view that supersymmetry and Lorentz symmetry are broken down at the same scale. If this is the case, the fermionic sector of the supermultiplets that accomplish the breaking of the symmetries into consideration may give rise to condensates that play an important role in the photon and photino dispersion relations. Contemporarily, they may also point to a more fundamental origin for the (bosonic) tensors usually associated to the backgrounds that parametrize Lorentz-symmetry breaking. We also highlight that, by studying the the violation of Lorentz symmetry in connection with supersymmetry, we find out that the Myers-Pospelov Electrodynamics, proposed on the basis of an analysis of the set of dimension-five operators, naturally appears in the bosonic sector of our model. Also, as a result of the interconnection between the supersymmetry and Lorentz-symmetry breakings, the photino-photino and photon-photino mixings that correspond to the supersymmetric completion of the Myers-Pospelov purely photonic terms come out. Finally, we present some comments on the possible modifications the supersymmetric fermions may introduce in the dispersion relations for particles at (high) energies close to the scale where supersymmetry and Lorentz symmetry are broken. (author)
Imprints of supersymmetry in the Lorentz-symmetry breaking of Gauge Theories
International Nuclear Information System (INIS)
Belich, H.; Dias, G.S.; Leal, F.J.L.; Durand, L.G.; Helayel-Neto, Jose Abdalla; Spalenza, W.
2011-01-01
Full text: The breaking of Lorentz symmetry that may take place at very high energies opens up a venue for the discussion of the interplay between the violations of supersymmetry and relativistic symmetry. Recently, there have appeared in the literature models which propose a residual (non-relativistic) supersymmetry after Lorentz symmetry has been broken in a Horava gravity scenario. We here propose an N=1-supersymmetric Abelian gauge model which realises the breaking of Lorentz invariance by means of a CPT-even term. Our attempt assumes the point of view that supersymmetry and Lorentz symmetry are broken down at the same scale. If this is the case, the fermionic sector of the supermultiplets that accomplish the breaking of the symmetries into consideration may give rise to condensates that play an important role in the photon and photino dispersion relations. Contemporarily, they may also point to a more fundamental origin for the (bosonic) tensors usually associated to the backgrounds that parametrize Lorentz-symmetry breaking. We also highlight that, by studying the the violation of Lorentz symmetry in connection with supersymmetry, we find out that the Myers-Pospelov Electrodynamics, proposed on the basis of an analysis of the set of dimension-five operators, naturally appears in the bosonic sector of our model. Also, as a result of the interconnection between the supersymmetry and Lorentz-symmetry breakings, the photino-photino and photon-photino mixings that correspond to the supersymmetric completion of the Myers-Pospelov purely photonic terms come out. Finally, we present some comments on the possible modifications the supersymmetric fermions may introduce in the dispersion relations for particles at (high) energies close to the scale where supersymmetry and Lorentz symmetry are broken. (author)
International Nuclear Information System (INIS)
O'Raifeartaigh, L.
1979-01-01
This review describes the principles of hidden gauge symmetry and of its application to the fundamental interactions. The emphasis is on the structure of the theory rather than on the technical details and, in order to emphasise the structure, gauge symmetry and hidden symmetry are first treated as independent phenomena before being combined into a single (hidden gauge symmetric) theory. The main application of the theory is to the weak and electromagnetic interactions of the elementary particles, and although models are used for comparison with experiment and for illustration, emphasis is placed on those features of the application which are model-independent. (author)
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.
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
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.)
Traces of Lorentz symmetry breaking in a hydrogen atom at ground state
International Nuclear Information System (INIS)
Borges, L.H.C.; Barone, F.A.
2016-01-01
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.)
International Nuclear Information System (INIS)
Dragon, N.
1979-01-01
The possible use of trilinear algebras as symmetry algebras for para-Fermi fields is investigated. The shortcomings of the examples are argued to be a general feature of such generalized algebras. (author)
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.
Segmentation Using Symmetry Deviation
DEFF Research Database (Denmark)
Hollensen, Christian; Højgaard, L.; Specht, L.
2011-01-01
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...... hypopharyngeal cancer patients to find anatomical symmetry and evaluate it against the standard deviation of the normal patients to locate pathologic volumes. Combining the information with an absolute PET threshold of 3 Standard uptake value (SUV) a volume was automatically delineated. The overlap of automated....... The standard deviation of the anatomical symmetry, seen in figure for one patient along CT and PET, was extracted for normal patients and compared with the deviation from cancer patients giving a new way of determining cancer pathology location. Using the novel method an overlap concordance index...
Statistical symmetries in physics
International Nuclear Information System (INIS)
Green, H.S.; Adelaide Univ., SA
1994-01-01
Every law of physics is invariant under some group of transformations and is therefore the expression of some type of symmetry. Symmetries are classified as geometrical, dynamical or statistical. At the most fundamental level, statistical symmetries are expressed in the field theories of the elementary particles. This paper traces some of the developments from the discovery of Bose statistics, one of the two fundamental symmetries of physics. A series of generalizations of Bose statistics is described. A supersymmetric generalization accommodates fermions as well as bosons, and further generalizations, including parastatistics, modular statistics and graded statistics, accommodate particles with properties such as 'colour'. A factorization of elements of ggl(n b ,n f ) can be used to define truncated boson operators. A general construction is given for q-deformed boson operators, and explicit constructions of the same type are given for various 'deformed' algebras. A summary is given of some of the applications and potential applications. 39 refs., 2 figs
Wigner's Symmetry Representation Theorem
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 10. Wigner's Symmetry Representation Theorem: At the Heart of Quantum Field Theory! Aritra Kr Mukhopadhyay. General Article Volume 19 Issue 10 October 2014 pp 900-916 ...
Dynamical symmetries for fermions
International Nuclear Information System (INIS)
Guidry, M.
1989-01-01
An introduction is given to the Fermion Dynamical Symmetry Model (FDSM). The analytical symmetry limits of the model are then applied to the calculation of physical quantities such as ground-state masses and B(E 2 ) values in heavy nuclei. These comparisons with data provide strong support for a new principle of collective motion, the Dynamical Pauli Effect, and suggest that dynamical symmetries which properly account for the pauli principle are much more persistent in nuclear structure than the corresponding boson symmetries. Finally, we present an assessment of criticisms which have been voiced concerning the FDSM, and a discussion of new phenomena and ''exotic spectroscopy'' which may be suggested by the model. 14 refs., 8 figs., 4 tabs
Flavour from accidental symmetries
International Nuclear Information System (INIS)
Ferretti, Luca; King, Stephen F.; Romanino, Andrea
2006-01-01
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
Broken ergodicity in two-dimensional homogeneous magnetohydrodynamic turbulence
International Nuclear Information System (INIS)
Shebalin, John V.
2010-01-01
Two-dimensional (2D) homogeneous magnetohydrodynamic (MHD) turbulence has many of the same qualitative features as three-dimensional (3D) homogeneous MHD turbulence. These features include several ideal (i.e., nondissipative) invariants along with the phenomenon of broken ergodicity (defined as nonergodic behavior over a very long time). 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 3D MHD turbulence that is manifest in the lowest wavenumbers was found. Here, we study the origin of broken ergodicity in 2D MHD turbulence. It will be seen that broken ergodicity in ideal 2D 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. The origins of broken ergodicity in an ideal 2D homogeneous MHD turbulence are found through an eigenanalysis of the covariance matrices of the probability density function and by an examination of the associated entropy functional. When the values of ideal invariants are kept fixed and grid size increases, it will be shown that the energy in a few large modes remains constant, while the energy in any other mode is inversely proportional to grid size. Also, as grid size increases, we find that broken ergodicity becomes manifest at more and more wavenumbers.
Parity Symmetry and Parity Breaking in the Quantum Rabi Model with Addition of Ising Interaction
International Nuclear Information System (INIS)
Wang Qiong; He Zhi; Yao Chun-Mei
2015-01-01
We explore the possibility to generate new parity symmetry in the quantum Rabi model after a bias is introduced. In contrast to a mathematical treatment in a previous publication [J. Phys. A 46 (2013) 265302], we consider a physically realistic method by involving an additional spin into the quantum Rabi model to couple with the original spin by an Ising interaction, and then the parity symmetry is broken as well as the scaling behavior of the ground state by introducing a bias. The rule can be found that the parity symmetry is broken by introducing a bias and then restored by adding new degrees of freedom. Experimental feasibility of realizing the models under discussion is investigated. (paper)
On the membrane paradigm and spontaneous breaking of horizon BMS symmetries
International Nuclear Information System (INIS)
Eling, Christopher; Oz, Yaron
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.
Evaluation of the Legibility of Broken Lines for Partial Sight
小林, 秀之
2000-01-01
The present study was designed to investigate the legibility of broken lines for persons with partial sight. The subjects were 10 persons with simulated partial sight, and 4 persons with partial sight. The simulation was obtained using filters and convex lenses. The 30 kind of broken lines was evaluated by the original test that the subjects were read directions of the broken lines in distinction from solid lines. The thickness of lines varied from 0.1mm. to 0.7mm. in 4 steps. The results...
Explicitly broken supersymmetry with exactly massless moduli
Energy Technology Data Exchange (ETDEWEB)
Dong, Xi [Stanford Institute for Theoretical Physics, Department of Physics, Stanford University,Stanford, CA 94305 (United States); Freedman, Daniel Z. [Stanford Institute for Theoretical Physics, Department of Physics, Stanford University,Stanford, CA 94305 (United States); Center for Theoretical Physics and Department of Mathematics,Massachusetts Institute of Technology,Cambridge, MA 02139 (United States); Zhao, Yue [Stanford Institute for Theoretical Physics, Department of Physics, Stanford University,Stanford, CA 94305 (United States)
2016-06-16
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 supergravity 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.
Quadratic contributions of softly broken supersymmetry in the light of loop regularization
Energy Technology Data Exchange (ETDEWEB)
Bai, Dong [Chinese Academy of Sciences, Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Beijing (China); University of Chinese Academy of Sciences, School of Physical Sciences, Beijing (China); Wu, Yue-Liang [Chinese Academy of Sciences, Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Beijing (China); International Centre for Theoretical Physics Asia-Pacific (ICTP-AP), Beijing (China); University of Chinese Academy of Sciences, School of Physical Sciences, Beijing (China)
2017-09-15
Loop regularization (LORE) is a novel regularization scheme in modern quantum field theories. It makes no change to the spacetime structure and respects both gauge symmetries and supersymmetry. As a result, LORE should be useful in calculating loop corrections in supersymmetry phenomenology. To further demonstrate its power, in this article we revisit in the light of LORE the old issue of the absence of quadratic contributions (quadratic divergences) in softly broken supersymmetric field theories. It is shown explicitly by Feynman diagrammatic calculations that up to two loops the Wess-Zumino model with soft supersymmetry breaking terms (WZ' model), one of the simplest models with the explicit supersymmetry breaking, is free of quadratic contributions. All the quadratic contributions cancel with each other perfectly, which is consistent with results dictated by the supergraph techniques. (orig.)
Nonrestoration of spontaneously broken P, CP and PQ at high temperature
International Nuclear Information System (INIS)
Dvali G.; Melfo, A.; Senjanovic, G.
1996-01-01
The possibility of P and CP violation at high temperature in models where these symmetries are spontaneously broken is investigated. It is found that in minimal models that include singlet fields, high T nonrestoration is possible for a wide range of parameters of the theory, in particular in models of CP violation with a CP-odd Higgs field. The same holds true for the invisible axion version of the Peccei-Quinn mechanism. This can provide both a way out for the domain wall problem in these theories and the CP violation required for baryogenesis. In the case of spontaneous P violation it turns out that high T nonrestoration required going beyond the minimal model. The results are shown to hold true when next-to-leading order effects are considered. (author). 33 refs, 3 figs
Large Top-Quark Mass and Nonlinear Representation of Flavor Symmetry
International Nuclear Information System (INIS)
Feldmann, Thorsten; Mannel, Thomas
2008-01-01
We consider an effective theory (ET) approach to flavor-violating processes beyond the standard model, where the breaking of flavor symmetry is described by spurion fields whose low-energy vacuum expectation values are identified with the standard model Yukawa couplings. Insisting on canonical mass dimensions for the spurion fields, the large top-quark Yukawa coupling also implies a large expectation value for the associated spurion, which breaks part of the flavor symmetry already at the UV scale Λ of the ET. Below that scale, flavor symmetry in the ET is represented in a nonlinear way by introducing Goldstone modes for the partly broken flavor symmetry and spurion fields transforming under the residual symmetry. As a result, the dominance of certain flavor structures in rare quark decays can be understood in terms of the 1/Λ expansion in the ET
Spontaneous symmetry breaking in vortex systems with two repulsive lengthscales.
Curran, P J; Desoky, W M; Milosević, M V; Chaves, A; Laloë, J-B; Moodera, J S; Bending, S J
2015-10-23
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.
Frozen and broken color: a matrix Schroedinger equation in the semiclassical limit
International Nuclear Information System (INIS)
Orbach, H.S.
1981-01-01
We consider the case of frozen color, i.e, where global color symmetry remains exact, but where colored states have a mass large compared to color-singlet mesons. Using semiclassical WKB formalism, we construct the spectrum of bound states. In order to determine the charge of the constituents, we then consider deep-inelastic scattering of an external probe (e.g., lepton) from our one-dimensional meson. We calculate explicitly the structure function, W, in the WKB limit and show how Lipkin's mechanism is manifested, as well as how scaling behavior comes. We derive the WKB formalism as a special case of a method of obtaining WKB type solutions for generalized Schroedinger equations for which the Hamiltonian is an arbitrary matrix function of any number of pairs of canonical operators. We generalize these considerations to the case of broken color symmetry - but where the breaking is not so strong as to allow low-lying states to have a large amount of mixing with the colored states. In this case, the degeneracy of excited colored states can be broken. We find that local excitation of color guarantees global excitation of color; i.e., if at a given energy colored semiclassical states can be constructed with size comparable to that of the ground state wave function, colored states of that energy will also exist in the spectrum of the full theory and will be observed. However, global existence of color does not guarantee the excitation of colored states via deep-inelastic processes
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
Effects of Initial Symmetry on the Global Symmetry of One-Dimensional Legal Cellular Automata
Directory of Open Access Journals (Sweden)
Ikuko Tanaka
2015-09-01
Full Text Available To examine the development of pattern formation from the viewpoint of symmetry, we applied a two-dimensional discrete Walsh analysis to a one-dimensional cellular automata model under two types of regular initial conditions. The amount of symmetropy of cellular automata (CA models under regular and random initial conditions corresponds to three Wolfram’s classes of CAs, identified as Classes II, III, and IV. Regular initial conditions occur in two groups. One group that makes a broken, regular pattern formation has four types of symmetry, whereas the other group that makes a higher hierarchy pattern formation has only two types. Additionally, both final pattern formations show an increased amount of symmetropy as time passes. Moreover, the final pattern formations are affected by iterations of base rules of CA models of chaos dynamical systems. The growth design formations limit possibilities: the ratio of developing final pattern formations under a regular initial condition decreases in the order of Classes III, II, and IV. This might be related to the difference in degree in reference to surrounding conditions. These findings suggest that calculations of symmetries of the structures of one-dimensional cellular automata models are useful for revealing rules of pattern generation for animal bodies.
Symmetry non-restoration at high temperature and supersymmetry
Dvali, Gia; Dvali, Gia
1996-01-01
We analyse the high temperature behaviour of softly broken supersymmetric theories taking into account the role played by effective non-renormalizable terms generated by the decoupling of superheavy degrees of freedom or the Planck scale physics. It turns out that discrete or continuous symmetries, spontaneously broken at intermediate scales, may never be restored, at least up to temperatures of the cutoff scale. There are a few interesting differences from the usual non-restoration in non-supersymmetric theories case where one needs at least two Higgs fields and non-restoration takes place for a range of parameters only. We show that with non-renormalizable interactions taken into account the non-restoration can occur for any nonzero range of parameters even for a single Higgs field. We show that such theories in general solve the cosmological domain wall problem, since the thermal production of the dangerous domain walls is enormously suppressed.
Broken homes, parental psychiatric illness, and female delinquency.
Offord, David R; Abrams, Nola; Allen, Nancy; Poushinsky, Mary
1979-04-01
Fifty-nine families with delinquent daughters were compared with 59 families, matched on socioeconomic class, with daughters of the same age who were not delinquent. The frequency of broken homes was found to be the strongest distinguishing factor between probands and controls. Parental disabilities appeared to play a part in the incidence of delinquency among girls, particularly when the disabilities result in a broken home.
Characterization and Preparation of Broken Rice Proteins Modified by Proteases
Directory of Open Access Journals (Sweden)
Lixia Hou
2010-01-01
Full Text Available Broken rice is an underutilized by-product of milling. Proteins prepared from broken rice by treatments with alkaline protease and papain have been characterized with regard to nutritional and functional properties. The protein content and the protein recovery were 56.45 and 75.45 % for alkaline protease treatment, and 65.45 and 46.32 % for papain treatment, respectively. Protease treatment increased the lysine and valine content, leading to a more balanced amino acid profile. Broken rice proteins had high emulsifying capacity, 58.3–71.6 % at neutral pH, and adequate water holding capacity, ranging from 1.96 to 2.93 g/g of proteins. At pH=7.0, the broken rice protein had the highest water holding capacity and the best interfacial activities (emulsifying capacity, emulsifying stability, foaming capacity and foaming stability, which may be the result of the higher solubility at pH=7.0. The interfacial activities increased with the increase in the mass fraction of broken rice proteins. The proteins prepared by the papain treatment had higher water holding capacity (p>0.05, emulsifying capacity (p0.05 than alkaline protease treatment at the same pH or mass fraction. To test the fortification of food products with broken rice proteins, pork sausages containing the proteins were prepared. Higher yield of the sausages was obtained with the increased content of broken rice proteins, in the range of 2.0–9.0 %. The results indicate that broken rice proteins have potential to be used as the protein fortification ingredient for food products.
Symmetry of priapulids (Priapulida). 2. Symmetry of larvae.
Adrianov, A V; Malakhov, V V
2001-02-01
Larvae of priapulids are characterized by radial symmetry evident from both external and internal characters of the introvert and lorica. The bilaterality appears as a result of a combination of several radial symmetries: pentaradial symmetry of the teeth, octaradial symmetry of the primary scalids, 25-radial symmetry of scalids, biradial symmetry of the neck, and biradial and decaradial symmetry of the trunk. Internal radiality is exhibited by musculature and the circumpharyngeal nerve ring. Internal bilaterality is evident from the position of the ventral nerve cord and excretory elements. Externally, the bilaterality is determined by the position of the anal tubulus and two shortened midventral rows of scalids bordering the ventral nerve cord. The lorical elements define the biradial symmetry that is missing in adult priapulids. The radial symmetry of larvae is a secondary appearance considered an evolutionary adaptation to a lifestyle within the three-dimensional environment of the benthic sediment. Copyright 2001 Wiley-Liss, Inc.
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.
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...
Schwichtenberg, Jakob
2018-01-01
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. Thanks to the input of readers from around the world, this second edition has been purged of typographical errors and also contains several revised sections with improved explanations. .
Chiral symmetry breaking and the pion quark structure
International Nuclear Information System (INIS)
Bernard, V.
1986-01-01
The mechanism of dynamical breaking of chiral symmetry in hadronic matter is first studied in the framework of the Nambu and Jona-Lasinio model on one hand and its generalisation to finite hadron size on the other hand. The analysis uses a variational procedure modelled after the BCS superconductor. Our study indicates for example, a great sensitivity of various quantities characterizing the breaking of symmetry to the shape of the interaction. Also the mechanism of breaking of chiral symmetry is essentially related to the mechanism of confinement. When a symmetry is spontaneously broken, there exists a Goldstone particle of zero mass. This is true in our model. This particle, the pion, is obtained as solution of a Bethe Salpeter equation for a qantiq bound state. This enables us to establish a connection between the pion as a Goldstone boson related to spontaneous symmetry breaking and the quark-antiquark structure of the pion. The finite mass of the physical pion is obtained with non zero current quark mass. Various properties of this particle are then studied in the RPA formalism. One important point of our model is the highly collective character of the pion. 85 refs [fr
Probing Fundamental Symmetries: Questioning the Very Basics of Conservation Laws
Mohanmurthy, Prajwal
2017-09-01
Is the Lorentz-CPT symmetry, a core component of the standard model, valid? To what extent are the CP and T symmetries broken in the strong sector? What are we doing about the existing strong-CP problem? Do neutrons oscillate (like neutral kaons) or break the (Baryon - Lepton) number conservation? In this presentation, we will go over some of the experiments probing fundamental symmetries trying to answer the above questions. I will, very briefly, introduce the CompEx & nEx experiments probing the Lorentz symmetry in the electromagnetic (EM) sector, the nEDM experiment probing CP and T symmetries in the strong sector, NStar experiment searching for neutron oscillations, MASS & BDX experiments searching for axion like particles & dark matter. We will then briefly touch upon the highlights of these experiments and focus on the path we are taking towards answering those questions while also connecting the dots [experiments] with CEU. PM would like to acknowledge support from SERI SNSF Grant 2015.0594.
Constraints on GUTS with Coleman-Weinberg symmetry breaking
International Nuclear Information System (INIS)
Sher, M.A.
1981-01-01
A popular assumption introduced by Coleman and Weinberg is that the elementary Higgs scalars of a gauge theory are massless at the tree level; the symmetry breakdown is then entirely due to quantum radiative corrections. In grand unified theories (GUTS), this assumption becomes particularly attractive. Many GUTS have intermediate mass scales [scales of symmetry breaking between baryon number generation and SU(2) x U(1) breaking], and it is attractive to apply the Coleman-Weinberg assumption to all stages of symmetry breaking after baryon number generation. In this paper, it is shown that most such GUTS are phenomenologically unacceptable. The reason is that as the universe cools, at each scale of symmetry breaking there will be a phase transition; if the symmetry is broken a la Coleman-Weinberg, this transition is strongly first order and thus generates entropy, decreasing the previously generated baryon number to entropy ratio by a large, and perhaps unacceptable amount. The entropy generated in a general intermediate mass scale transition is calculated, and the severe constraints that any Coleman-Weinberg-type GUT with intermediate mass scales must satisfy (in order to avoid excessive entropy generation) are found. Turning to specific models, it is shown that all intermediate mass scale transitions associated with SO(10) do not satisfy these constraints; the Coleman-Weinberg form of these transitions is inconsistent with cosmological observations and is thus phenomenologically unacceptable. (orig.)
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
International Nuclear Information System (INIS)
Chimento, Luis P.
2002-01-01
We find the group of symmetry transformations under which the Einstein equations for the spatially flat Friedmann-Robertson-Walker universe are form invariant. They relate the energy density and the pressure of the fluid to the expansion rate. We show that inflation can be obtained from nonaccelerated scenarios by a symmetry transformation. We derive the transformation rule for the spectrum and spectral index of the curvature perturbations. Finally, the group is extended to investigate inflation in the anisotropic Bianchi type-I spacetime and the brane-world cosmology
International Nuclear Information System (INIS)
Snyderman, N.J.
1976-01-01
The Schwinger-Dyson equation for the Nambu-Jona Lasinio model is solved systematically subject to the constraint of spontaneously broken chiral symmetry. The solution to this equation generates interactions not explicitly present in the original Lagrangian, and the original 4-fermion interaction is not present in the solution. The theory creates bound-states with respect to which a perturbation theory consistent with the chiral symmetry is set up. The analysis suggests that this theory is renormalizable in the sense that all divergences can be grouped into a few arbitrary parameters. The renormalized propagators of this model are shown to be identical to those of a new solution to the sigma-model in which the bare 4-field coupling lambda 0 is chosen to be twice the π-fermion coupling g 0 . Also considered is spontaneously broken abelian gauge model without fundamental scalar fields by coupling an axial vector gauge field to the N ambu-Jona Lasinio model. It is shown how the Goldstone consequence of spontaneous symmetry breaking is avoided in the radiation gauge, and verify the Guralnik, Hagen, and Kibble theorem that under these conditions the global charge conservation is lost even though there is still local current conservation. This is contrasted with the Lorentz gauge situation. This also demonstrated the way the various noncovariant components of the massive gauge field combine in a gauge invariant scattering amplitude to propagate covariantly as a massive spin-1 particle, and this is compared with the Lorentz gauge calculation. F inally, a new model of interacting massless fermions is introduced, based on the models of Nambu and Jona Lasinio, and the Bjorken, which spontaneously breaks both chiral symmetry and Lorentz invariance. The content of this model is the same as that of the gauge model without fundamental scalar fields, but without fundamental gauge fields as well
Spatial and Spin Symmetry Breaking in Semidefinite-Programming-Based Hartree-Fock Theory.
Nascimento, Daniel R; DePrince, A Eugene
2018-05-08
The Hartree-Fock problem was recently recast as a semidefinite optimization over the space of rank-constrained two-body reduced-density matrices (RDMs) [ Phys. Rev. A 2014 , 89 , 010502(R) ]. This formulation of the problem transfers the nonconvexity of the Hartree-Fock energy functional to the rank constraint on the two-body RDM. We consider an equivalent optimization over the space of positive semidefinite one-electron RDMs (1-RDMs) that retains the nonconvexity of the Hartree-Fock energy expression. The optimized 1-RDM satisfies ensemble N-representability conditions, and ensemble spin-state conditions may be imposed as well. The spin-state conditions place additional linear and nonlinear constraints on the 1-RDM. We apply this RDM-based approach to several molecular systems and explore its spatial (point group) and spin ( Ŝ 2 and Ŝ 3 ) symmetry breaking properties. When imposing Ŝ 2 and Ŝ 3 symmetry but relaxing point group symmetry, the procedure often locates spatial-symmetry-broken solutions that are difficult to identify using standard algorithms. For example, the RDM-based approach yields a smooth, spatial-symmetry-broken potential energy curve for the well-known Be-H 2 insertion pathway. We also demonstrate numerically that, upon relaxation of Ŝ 2 and Ŝ 3 symmetry constraints, the RDM-based approach is equivalent to real-valued generalized Hartree-Fock theory.
Hermes, Matthew R.; Dukelsky, Jorge; Scuseria, Gustavo E.
2017-06-01
The failures of single-reference coupled-cluster theory for strongly correlated many-body systems is flagged at the mean-field level by the spontaneous breaking of one or more physical symmetries of the Hamiltonian. Restoring the symmetry of the mean-field determinant by projection reveals that coupled-cluster theory fails because it factorizes high-order excitation amplitudes incorrectly. However, symmetry-projected mean-field wave functions do not account sufficiently for dynamic (or weak) correlation. Here we pursue a merger of symmetry projection and coupled-cluster theory, following previous work along these lines that utilized the simple Lipkin model system as a test bed [J. Chem. Phys. 146, 054110 (2017), 10.1063/1.4974989]. We generalize the concept of a symmetry-projected mean-field wave function to the concept of a symmetry projected state, in which the factorization of high-order excitation amplitudes in terms of low-order ones is guided by symmetry projection and is not exponential, and combine them with coupled-cluster theory in order to model the ground state of the Agassi Hamiltonian. This model has two separate channels of correlation and two separate physical symmetries which are broken under strong correlation. We show how the combination of symmetry collective states and coupled-cluster theory is effective in obtaining correlation energies and order parameters of the Agassi model throughout its phase diagram.
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.
Fermion mass hierarchies and flavor mixing from T' symmetry
International Nuclear Information System (INIS)
Ding Guijun
2008-01-01
We construct a supersymmetric model based on T ' x Z 3 x Z 9 flavor symmetry. At the leading order, the charged lepton mass matrix is not diagonal, T ' is broken completely, and the hierarchy in the charged lepton masses is generated naturally. Nearly tribimaximal mixing is predicted, and subleading effects induce corrections of order λ 2 , where λ is the Cabibbo angle. Both the up quark and down quark mass matrices' textures of the well-known U(2) flavor theory are produced at the leading order; realistic hierarchies in quark masses and Cabibbo-Kobayashi-Maskawa matrix elements are obtained. The vacuum alignment and subleading corrections are discussed in detail.
Symmetry breaking in clogging for oppositely driven particles
Glanz, Tobias; Wittkowski, Raphael; Löwen, Hartmut
2016-11-01
The clogging behavior of a symmetric binary mixture of colloidal particles that are driven in opposite directions through constrictions is explored by Brownian dynamics simulations and theory. A dynamical state with a spontaneously broken symmetry occurs where one species is flowing and the other is blocked for a long time, which can be tailored by the size of the constrictions. Moreover, we find self-organized oscillations in clogging and unclogging of the two species. Apart from statistical physics, our results are of relevance for fields like biology, chemistry, and crowd management, where ions, microparticles, pedestrians, or other particles are driven in opposite directions through constrictions.
Neutral meson tests of time-reversal symmetry invariance
Bevan, Adrian; Inguglia, Gianluca; Zoccali, Michele
2013-01-01
The laws of quantum physics can be studied under the mathematical operation T that inverts the direction of time. Strong and electromagnetic forces are known to be invariant under temporal inversion, however the weak force is not. The BaBar experiment recently exploited the quantum-correlated production of pairs of B0 mesons to show that T is a broken symmetry. Here we show that it is possible to perform a wide range of tests of quark flavour changing processes under T in order to validate th...
Introduction to Chiral Symmetry
Energy Technology Data Exchange (ETDEWEB)
Koch, Volker [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
2017-05-09
These lectures are an attempt to a pedagogical introduction into the elementary concepts of chiral symmetry in nuclear physics. We will also discuss some effective chiral models such as the linear and nonlinear sigma model as well as the essential ideas of chiral perturbation theory. We will present some applications to the physics of ultrarelativistic heavy ion collisionsd.
Jinzenji, Masao
2018-01-01
This book furnishes a brief introduction to classical mirror symmetry, a term that denotes the process of computing Gromov–Witten invariants of a Calabi–Yau threefold by using the Picard–Fuchs differential equation of period integrals of its mirror Calabi–Yau threefold. The book concentrates on the best-known example, the quintic hypersurface in 4-dimensional projective space, and its mirror manifold. First, there is a brief review of the process of discovery of mirror symmetry and the striking result proposed in the celebrated paper by Candelas and his collaborators. Next, some elementary results of complex manifolds and Chern classes needed for study of mirror symmetry are explained. Then the topological sigma models, the A-model and the B-model, are introduced. The classical mirror symmetry hypothesis is explained as the equivalence between the correlation function of the A-model of a quintic hyper-surface and that of the B-model of its mirror manifold. On the B-model side, the process of construct...
Approximate symmetries of Hamiltonians
Chubb, Christopher T.; Flammia, Steven T.
2017-08-01
We explore the relationship between approximate symmetries of a gapped Hamiltonian and the structure of its ground space. We start by considering approximate symmetry operators, defined as unitary operators whose commutators with the Hamiltonian have norms that are sufficiently small. We show that when approximate symmetry operators can be restricted to the ground space while approximately preserving certain mutual commutation relations. We generalize the Stone-von Neumann theorem to matrices that approximately satisfy the canonical (Heisenberg-Weyl-type) commutation relations and use this to show that approximate symmetry operators can certify the degeneracy of the ground space even though they only approximately form a group. Importantly, the notions of "approximate" and "small" are all independent of the dimension of the ambient Hilbert space and depend only on the degeneracy in the ground space. Our analysis additionally holds for any gapped band of sufficiently small width in the excited spectrum of the Hamiltonian, and we discuss applications of these ideas to topological quantum phases of matter and topological quantum error correcting codes. Finally, in our analysis, we also provide an exponential improvement upon bounds concerning the existence of shared approximate eigenvectors of approximately commuting operators under an added normality constraint, which may be of independent interest.
Molecular symmetry and spectroscopy
Bunker, Philip; Jensen, Per
2006-01-01
The first edition, by P.R. Bunker, published in 1979, remains the sole textbook that explains the use of the molecular symmetry group in understanding high resolution molecular spectra. Since 1979 there has been considerable progress in the field and a second edition is required; the original author has been joined in its writing by Per Jensen. The Material of the first edition has been reorganized and much has been added. The molecular symmetry group is now introduced early on, and the explanation of how to determine nuclear spin statistical weights has been consolidated in one chapter, after groups, symmetry groups, character tables and the Hamiltonian have been introduced. A description of the symmetry in the three-dimensional rotation group K(spatial), irreducible spherical tensor operators, and vector coupling coefficients is now included. The chapters on energy levels and selection rules contain a great deal of material that was not in the first edition (much of it was undiscovered in 1979), concerning ...
Introduction to chiral symmetry
International Nuclear Information System (INIS)
Koch, V.
1996-01-01
These lectures are an attempt to a pedagogical introduction into the elementary concepts of chiral symmetry in nuclear physics. Effective chiral models such as the linear and nonlinear sigma model will be discussed as well as the essential ideas of chiral perturbation theory. Some applications to the physics of ultrarelativistic heavy ion collisions will be presented
Pels, D.L.
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
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...
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 10. Groups and Symmetry: A Guide to Discovering Mathematics. Geetha Venkataraman. Book Review Volume 4 Issue 10 October 1999 pp 91-92. Fulltext. Click here to view fulltext PDF. Permanent link:
International Nuclear Information System (INIS)
Sezgin, E.
1991-08-01
We review the structure of W ∞ algebras, their super and topological extensions, and their contractions down to (super) w ∞ . Emphasis is put on the field theoretic realizations of these algebras. We also review the structure of w ∞ and W ∞ gravities and comment on various applications of W ∞ symmetry. (author). 42 refs
International Nuclear Information System (INIS)
Hojman, Sergio A.
1996-01-01
The purpose of these lectures is to present some of the ways in which non-Noetherian symmetries are used in contemporary mathematical physics. These include, among others, obtaining conservation laws for dynamical systems, solving non-linear problems, getting alternative Lagrangians for systems of differential equations and constructing symplectic structures and Hamiltonians for dynamical systems starting from scratch
Detection symmetry and asymmetry
du Buf, J.M.H.
1991-01-01
Experiments were performed on the detection symmetry and asymmetry of incremental and decremental disks, as a function of both disk diameter and duration. It was found that, for a background luminance of 300cd.m-2, thresholds of dynamic (briefly presented) foveal disks are symmetrical for all
International Nuclear Information System (INIS)
Stern, J.
2000-01-01
The problem of a uniform description of symmetries, their dynamic disturbing and the structure of the vacuum is discussed. The role which problems of this kind played in searching for and understanding the Standard Model of elementary particles from the 1960s till now is also highlighted. (Z.J.)
Fields, symmetries, and quarks
International Nuclear Information System (INIS)
Mosel, U.
1989-01-01
'Fields, symmetries, and quarks' covers elements of quantum field theory, symmetries, gauge field theories and phenomenological descriptions of hadrons, with special emphasis on topics relevant to nuclear physics. It is aimed at nuclear physicists in general and at scientists who need a working knowledge of field theory, symmetry principles of elementary particles and their interactions and the quark structure of hadrons. The book starts out with an elementary introduction into classical field theory and its quantization. As gauge field theories require a working knowledge of global symmetries in field theories this topic is then discussed in detail. The following part is concerned with the general structure of gauge field theories and contains a thorough discussion of the still less widely known features of Non-Abelian gauge field theories. Quantum Chromodynamics (QCD), which is important for the understanding of hadronic matter, is discussed in the next section together with the quark compositions of hadrons. The last two chapters give a detailed discussion of phenomenological bag-models. The MIT bag is discussed, so that all theoretical calculations can be followed step by step. Since in all other bag-models the calculational methods and steps are essentially identical, this chapter should enable the reader to actually perform such calculations unaided. A last chapter finally discusses the topological bag-models which have become quite popular over the last few years. (orig.)
Symmetry of priapulids (Priapulida). 1. Symmetry of adults.
Adrianov, A V; Malakhov, V V
2001-02-01
Priapulids possess a radial symmetry that is remarkably reflected in both external morphology and internal anatomy. It results in the appearance of 25-radial (a number divisible by five) symmetry summarized as a combination of nonaradial, octaradial, and octaradial (9+8+8) symmetries of scalids. The radial symmetry is a secondary appearance considered as an evolutionary adaptation to a lifestyle within the three-dimensional environment of bottom sediment. The eight anteriormost, or primary, scalids retain their particular position because of their innervation directly from the circumpharyngeal brain. As a result of a combination of the octaradial symmetry of primary scalids, pentaradial symmetry of teeth, and the 25-radial symmetry of scalids, the initial bilateral symmetry remains characterized by the single sagittal plane. Copyright 2001 Wiley-Liss, Inc.
Reconstruction of the spontaneously broken gauge theory in non-commutative geometry
International Nuclear Information System (INIS)
Okumura, Y.; Morita, K.
1996-01-01
The scheme previously proposed by the present authors is modified to incorporate the strong interaction by affording the direct product internal symmetry. The authors do not need to prepare the extra discrete space for the colour gauge group responsible for the strong interaction to reconstruct the standard model and the left-right symmetric gauge model (LRSM). The approach based on non-commutative geometry leads us to present many attractive points such as the unified picture of the gauge and Higgs field as the generalized connection on the discrete space M 4 x Z N . This approach leads to unified picture of gauge and Higgs fields as the generalized connection. The standard model needs N=2 discrete space for reconstruction in this formalism. LRSM is still alive as a model with the intermediate symmetry of the spontaneously broken SO(10) grand unified theory (GUT). N=3 discrete space is needed for the reconstruction of LRSM to include two Higgs φ and ξ bosons usual transformed as (2, 2 * , 0) and (1, 3, -2) under SU(2) L x SU(2) R x U(1) Y , respectively. ξ is responsible to make v R Majorana fermion and so well explains the seesaw mechanism. Up and down quarks have different masses through the vacuum expectation value of φ
International Nuclear Information System (INIS)
Capri, Marcio; Justo, Igor; Guimaraes, Marcelo; Sorella, Silvio; Dudal, David; Palhares, Leticia
2013-01-01
Full text: In recent years much attention has been devoted to the study of the issue of the Gribov copies and of its relevance for confinement in Yang-Mills theories. The existence of the Gribov copies is a general feature of the gauge-fixing quantization procedure, being related to the impossibility of finding a local gauge condition which picks up only one gauge configuration for each gauge orbit. As it has been shown by Gribov and Zwanziger, a partial solution of the Gribov problem in the Landau gauge can be achieved by restricting the domain of integration in the functional Euclidean integral to the first Gribov horizon. Among the various open aspects of the Gribov-Zwanziger framework, the issue of the BRST symmetry is a source of continuous investigations. In a recent work, we have been able to obtain an equivalent formulation of the Gribov-Zwanziger action which displays an exact BRST symmetry which turns out to be spontaneously broken by the restriction of the domain of integration to the Gribov horizon. In particular, the BRST operator retains the important property of being nilpotent. Moreover, it has also been shown that the Goldstone mode associated to the spontaneous breaking of the BRST symmetry is completely decoupled. The aim of the present work is that of fills up a gap not addressed in the previous work, namely, the renormalizability to all orders of the spontaneous symmetry breaking formulation of the Gribov-Zwanziger theory. As we shall see, the action obtained enjoys a large set of Ward identities which enables to prove that it is, in fact, multiplicatively renormalizable to all orders. (author)
Proton-neutron correlations in a broken-pair model
International Nuclear Information System (INIS)
Akkermans, J.N.L.
1981-01-01
In this thesis nuclear-structure calculations are reported which were performed with the broken-pair model. The model which is developed, is an extension of existing broken-pair models in so far that it includes both proton and neutron valence pairs. The relevant formalisms are presented. In contrast to the number-non-conserving model, a proton-neutron broken-pair model is well suited to study the correlations which are produced by the proton-neutron interaction. It is shown that the proton-neutron force has large matrix elements which mix the proton- with neutron broken-pair configurations. This occurs especially for Jsup(PI)=2 + and 3 - pairs. This property of the proton-neutron force is used to improve the spectra of single-closed shell nuclei, where particle-hole excitations of the closed shell are a special case of broken-pair configurations. Using Kr and Te isotopes it is demonstrated that the proton-neutron force gives rise to correlated pair structures, which remain remarkably constant with varying nucleon numbers. (Auth.)
Broken-Rotor-Bar Diagnosis for Induction Motors
International Nuclear Information System (INIS)
Wang Jinjiang; Gao, Robert X; Yan Ruqiang
2011-01-01
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.
Spontaneous symmetry breaking in curved space-time
International Nuclear Information System (INIS)
Toms, D.J.
1982-01-01
An approach dealing with some of the complications which arise when studying spontaneous symmetry breaking beyond the tree-graph level in situations where the effective potential may not be used is discussed. These situations include quantum field theory on general curved backgrounds or in flat space-times with non-trivial topologies. Examples discussed are a twisted scalar field in S 1 xR 3 and instabilities in an expanding universe. From these it is seen that the topology and curvature of a space-time may affect the stability of the vacuum state. There can be critical length scales or times beyond which symmetries may be broken or restored in certain cases. These features are not present in Minkowski space-time and so would not show up in the usual types of early universe calculations. (U.K.)
Symmetry breaking in the double-well hermitian matrix models
International Nuclear Information System (INIS)
Brower, R.C.; Deo, N.; Jain, S.; Tan, C.I.
1993-01-01
We study symmetry breaking in Z 2 symmetric large N matrix models. In the planar approximation for both the symmetric double-well φ 4 model and the symmetric Penner model, we find there is an infinite family of broken symmetry solutions characterized by different sets of recursion coefficients R n and S n that all lead to identical free energies and eigenvalue densities. These solutions can be parameterized by an arbitrary angle θ(x), for each value of x=n/N 4 theory the double scaling string equations are parameterized by a conserved angular momentum parameter in the range 0≤l<∞ and a single arbitrary U(1) phase angle. (orig.)
Symmetry breaking in the double-well hermitian matrix models
Brower, R C; Jain, S; Tan, C I; Brower, Richard C.; Deo, Nevidita; Jain, Sanjay; Tan, Chung-I
1993-01-01
We study symmetry breaking in $Z_2$ symmetric large $N$ matrix models. In the planar approximation for both the symmetric double-well $\\phi^4$ model and the symmetric Penner model, we find there is an infinite family of broken symmetry solutions characterized by different sets of recursion coefficients $R_n$ and $S_n$ that all lead to identical free energies and eigenvalue densities. These solutions can be parameterized by an arbitrary angle $\\theta(x)$, for each value of $x = n/N < 1$. In the double scaling limit, this class reduces to a smaller family of solutions with distinct free energies already at the torus level. For the double-well $\\phi^4$ theory the double scaling string equations are parameterized by a conserved angular momentum parameter in the range $0 \\le l < \\infty$ and a single arbitrary $U(1)$ phase angle.
Radiative breaking scenario for the GUT gauge symmetry
International Nuclear Information System (INIS)
Fukuyama, T.; Kikuchi, T.
2006-01-01
The origin of the grand unified theory (GUT) scale from the top-down perspective is explored. The GUT gauge symmetry is broken by the renormalization group effects, which is an extension of the radiative electroweak symmetry breaking scenario to the GUT models. That is, in the same way as the origin of the electroweak scale, the GUT scale is generated from the Planck scale through the radiative corrections to the soft supersymmetry breaking mass parameters. This mechanism is applied to a perturbative SO(10) GUT model, recently proposed by us. In the SO(10) model, the relation between the GUT scale and the Planck scale can naturally be realized by using order-one coupling constants. (orig.)
Symmetries in physics and harmonics
International Nuclear Information System (INIS)
Kolk, D.
2006-01-01
In this book the symmetries of elementary particles are described in relation to the rules of harmonics in music. The selection rules are described in connections with harmonic intervals. Also symmetry breaking is considered in this framework. (HSI)
Spontaneous symmetry breaking of (1+1)-dimensional φ4 theory in light-front field theory
International Nuclear Information System (INIS)
Bender, C.M.; Pinsky, S.; van de Sande, B.
1993-01-01
We study spontaneous symmetry breaking in (1+1)-dimensional φ 4 theory using the light-front formulation of field theory. Since the physical vacuum is always the same as the perturbative vacuum in light-front field theory the fields must develop a vacuum expectation value through the zero-mode components of the field. We solve the nonlinear operator equation for the zero mode in the one-mode approximation. We find that spontaneous symmetry breaking occurs at λ critical =4π(3+ √3 )μ 2 , which is consistent with the value λ critical =54.27μ 2 obtained in the equal-time theory. We calculate the vacuum expectation value as a function of the coupling constant in the broken phase both numerically and analytically using the δ expansion. We find two equivalent broken phases. Finally we show that the energy levels of the system have the expected behavior for the broken phase
Unified Symmetry of Hamilton Systems
International Nuclear Information System (INIS)
Xu Xuejun; Qin Maochang; Mei Fengxiang
2005-01-01
The definition and the criterion of a unified symmetry for a Hamilton system are presented. The sufficient condition under which the Noether symmetry is a unified symmetry for the system is given. A new conserved quantity, as well as the Noether conserved quantity and the Hojman conserved quantity, deduced from the unified symmetry, is obtained. An example is finally given to illustrate the application of the results.
Quantum symmetries in particle interactions
International Nuclear Information System (INIS)
Shirkov, D.V.
1983-01-01
The concept of a quantum symmetry is introduced as a symmetry in the formulation of which quantum representations and specific quantum notions are used essentially. Three quantum symmetry principles are discussed: the principle of renormalizability (possibly super-renormalizability), the principle of local gauge symmetry, and the principle of supersymmetry. It is shown that these principles play a deterministic role in the development of quantum field theory. Historically their use has led to ever stronger restrictions on the interaction mechanism of quantum fields
Symmetry and topology in evolution
International Nuclear Information System (INIS)
Lukacs, B.; Berczi, S.; Molnar, I.; Paal, G.
1991-10-01
This volume contains papers of an interdisciplinary symposium on evolution. The aim of this symposium, held in Budapest, Hungary, 28-29 May 1991, was to clear the role of symmetry and topology at different levels of the evolutionary processes. 21 papers were presented, their topics included evolution of the Universe, symmetry of elementary particles, asymmetry of the Earth, symmetry and asymmetry of biomolecules, symmetry and topology of lining objects, human asymmetry etc. (R.P.)
A Longitudianl Study of the Link Between Broken Homes and Criminality.
McCord, Joan
Possible explanatory theories of the relationship between broken homes and crime include the following: (1) broken homes lead to crimes if there are "catalytic agents"; (2) broken homes lead to crime if these homes fail to provide certain conditions which promote socialization; and (3) broken homes and crime have a common source, but not…
Charge independence and charge symmetry
Energy Technology Data Exchange (ETDEWEB)
Miller, G A [Washington Univ., Seattle, WA (United States). Dept. of Physics; van Oers, W T.H. [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Physics; [TRIUMF, Vancouver, BC (Canada)
1994-09-01
Charge independence and charge symmetry are approximate symmetries of nature, violated by the perturbing effects of the mass difference between up and down quarks and by electromagnetic interactions. The observations of the symmetry breaking effects in nuclear and particle physics and the implications of those effects are reviewed. (author). 145 refs., 3 tabs., 11 figs.
Charge independence and charge symmetry
International Nuclear Information System (INIS)
Miller, G.A.
1994-09-01
Charge independence and charge symmetry are approximate symmetries of nature, violated by the perturbing effects of the mass difference between up and down quarks and by electromagnetic interactions. The observations of the symmetry breaking effects in nuclear and particle physics and the implications of those effects are reviewed. (author). 145 refs., 3 tabs., 11 figs
Symmetry energy in nuclear surface
International Nuclear Information System (INIS)
Danielewicz, P.; Lee, Jenny
2009-01-01
Interplay between the dependence of symmetry energy on density and the variation of nucleonic densities across nuclear surface is discussed. That interplay gives rise to the mass dependence of the symmetry coefficient in an energy formula. Charge symmetry of the nuclear interactions allows to introduce isoscalar and isovector densities that are approximately independent of the magnitude of neutron-proton asymmetry. (author)
Emergence of Symmetries from Entanglement
CERN. Geneva
2016-01-01
Maximal Entanglement appears to be a key ingredient for the emergence of symmetries. We first illustrate this phenomenon using two examples: the emergence of conformal symmetry in condensed matter systems and the relation of tensor networks to holography. We further present a Principle of Maximal Entanglement that seems to dictate to a large extend the structure of gauge symmetry.
Group analysis and renormgroup symmetries
International Nuclear Information System (INIS)
Kovalev, V.F.; Pustovalov, V.V.; Shirkov, D.V.
1996-01-01
An original regular approach to constructing special type symmetries for boundary-value problems, namely renormgroup symmetries, is presented. Different methods of calculating these symmetries based on modern group analysis are described. An application of the approach to boundary value problems is demonstrated with the help of a simple mathematical model. 35 refs
Management of broken instrument by file bypass technique
Directory of Open Access Journals (Sweden)
Sultana Parveen
2017-02-01
Full Text Available Different devices and techniques have been developed to retrieve fractured instruments during the endodontic procedures. This case report describes the management of a broken instrument, which was accidentally broken during cleaning and shaping of the root canal in right 2nd molar tooth. A # 25 stainless steel K-file was separated in mesiobuccal canal of the treated tooth. At first, a radiograph was taken to confirm the level of separation of the instrument. The instrument was found to be separated at the apical 3rd of the mesial canal and then file bypass technique was performed. Calcium hydroxide dressing was given for 7 days followed by obturation with guttapercha cone and zinc oxide eugenol sealer in lateral condensation technique. It can be concluded that bypass technique can be considered as simple and effective technique for the management of broken instrument into the root canal.
Dark discrete gauge symmetries
International Nuclear Information System (INIS)
Batell, Brian
2011-01-01
We investigate scenarios in which dark matter is stabilized by an Abelian Z N discrete gauge symmetry. Models are surveyed according to symmetries and matter content. Multicomponent dark matter arises when N is not prime and Z N contains one or more subgroups. The dark sector interacts with the visible sector through the renormalizable kinetic mixing and Higgs portal operators, and we highlight the basic phenomenology in these scenarios. In particular, multiple species of dark matter can lead to an unconventional nuclear recoil spectrum in direct detection experiments, while the presence of new light states in the dark sector can dramatically affect the decays of the Higgs at the Tevatron and LHC, thus providing a window into the gauge origin of the stability of dark matter.
Symmetries and microscopic physics
International Nuclear Information System (INIS)
Blaizot, J.P.
1997-01-01
This book is based on a course of lectures devoted to the applications of group theory to quantum physics. The purpose is to give students a precise idea of general principles involving the concept of symmetry and to present practical methods used to calculate physical properties derived from symmetries. The first chapter is an introduction to the main results of group theory, 2 chapters highlight principles and methods concerning geometrical transformations in the space of states, state degeneracy and perturbation theory. The last 4 chapters investigate the applications of these methods to atom physics, nuclear structure and elementary particles. A chapter is devoted to the atom of hydrogen and another to the isospin. Numerous exercises and problems, some with their corrections, are proposed. (A.C.)
Asymmetry, Symmetry and Beauty
Directory of Open Access Journals (Sweden)
Abbe R. Kopra
2010-07-01
Full Text Available Asymmetry and symmetry coexist in natural and human processes. The vital role of symmetry in art has been well demonstrated. This article highlights the complementary role of asymmetry. Further we show that the interaction of asymmetric action (recursion and symmetric opposition (sinusoidal waves are instrumental in generating creative features (relatively low entropy, temporal complexity, novelty (less recurrence in the data than in randomized copies and complex frequency composition. These features define Bios, a pattern found in musical compositions and in poetry, except for recurrence instead of novelty. Bios is a common pattern in many natural and human processes (quantum processes, the expansion of the universe, gravitational waves, cosmic microwave background radiation, DNA, physiological processes, animal and human populations, and economic time series. The reduction in entropy is significant, as it reveals creativity and contradicts the standard claim of unavoidable decay towards disorder. Artistic creations capture fundamental features of the world.
Strong Electroweak Symmetry Breaking
Grinstein, Benjamin
2011-01-01
Models of spontaneous breaking of electroweak symmetry by a strong interaction do not have fine tuning/hierarchy problem. They are conceptually elegant and use the only mechanism of spontaneous breaking of a gauge symmetry that is known to occur in nature. The simplest model, minimal technicolor with extended technicolor interactions, is appealing because one can calculate by scaling up from QCD. But it is ruled out on many counts: inappropriately low quark and lepton masses (or excessive FCNC), bad electroweak data fits, light scalar and vector states, etc. However, nature may not choose the minimal model and then we are stuck: except possibly through lattice simulations, we are unable to compute and test the models. In the LHC era it therefore makes sense to abandon specific models (of strong EW breaking) and concentrate on generic features that may indicate discovery. The Technicolor Straw Man is not a model but a parametrized search strategy inspired by a remarkable generic feature of walking technicolor,...
Symmetry rules. How science and nature are founded on symmetry
Energy Technology Data Exchange (ETDEWEB)
Rosen, J.
2008-07-01
When we use science to describe and understand the world around us, we are in essence grasping nature through symmetry. In fact, modern theoretical physics suggests that symmetry is a, if not the, foundational principle of nature. Emphasizing the concepts, this book leads the reader coherently and comprehensively into the fertile field of symmetry and its applications. Among the most important applications considered are the fundamental forces of nature and the Universe. It is shown that the Universe cannot possess exact symmetry, which is a principle of fundamental significance. Curie's principle - which states that the symmetry of the effect is at least that of the cause - features prominently. An introduction to group theory, the mathematical language of symmetry, is included. This book will convince all interested readers of the importance of symmetry in science. Furthermore, it will serve as valuable background reading for all students in the physical sciences. (orig.)
Symmetry rules How science and nature are founded on symmetry
Rosen, Joe
2008-01-01
When we use science to describe and understand the world around us, we are in essence grasping nature through symmetry. In fact, modern theoretical physics suggests that symmetry is a, if not the, foundational principle of nature. Emphasizing the concepts, this book leads the reader coherently and comprehensively into the fertile field of symmetry and its applications. Among the most important applications considered are the fundamental forces of nature and the Universe. It is shown that the Universe cannot possess exact symmetry, which is a principle of fundamental significance. Curie's principle - which states that the symmetry of the effect is at least that of the cause - features prominently. An introduction to group theory, the mathematical language of symmetry, is included. This book will convince all interested readers of the importance of symmetry in science. Furthermore, it will serve as valuable background reading for all students in the physical sciences.
Symmetry and quantum mechanics
Corry, Scott
2016-01-01
This book offers an introduction to quantum mechanics for professionals, students, and others in the field of mathematics who have a minimal background in physics with an understanding of linear algebra and group theory. It covers such topics as Lie groups, algebras and their representations, and analysis (Hilbert space, distributions, the spectral Theorem, and the Stone-Von Neumann Theorem). The book emphasizes the role of symmetry and is useful to physicists as it provides a mathematical introduction to the topic.
Gravitation, Symmetry and Undergraduates
Jorgensen, Jamie
2001-04-01
This talk will discuss "Project Petrov" Which is designed to investigate gravitational fields with symmetry. Project Petrov represents a collaboration involving physicists, mathematicians as well as graduate and undergraduate math and physics students. An overview of Project Petrov will be given, with an emphasis on students' contributions, including software to classify and generate Lie algebras, to classify isometry groups, and to compute the isometry group of a given metric.
International Nuclear Information System (INIS)
Bunakov, V.E.; Ivanov, I.B.
1999-01-01
Connections between the symmetries of Hamiltonian systems in classical and quantum mechanics, on one hand, and their regularity or chaoticity, on the other hand, are considered. The quantum-chaoticity criterion that was proposed previously and which was borrowed from the theory of compound-nucleus resonances is used to analyze the quantum diamagnetic Kepler problem - that is, the motion of a spinless charged particle in a Coulomb and a uniform magnetic field
International Nuclear Information System (INIS)
French, J.B.
1974-01-01
The concepts of statistical behavior and symmetry are presented from the point of view of many body spectroscopy. Remarks are made on methods for the evaluation of moments, particularly widths, for the purpose of giving a feeling for the types of mathematical structures encountered. Applications involving ground state energies, spectra, and level densities are discussed. The extent to which Hamiltonian eigenstates belong to irreducible representations is mentioned. (4 figures, 1 table) (U.S.)
Energy Technology Data Exchange (ETDEWEB)
Herrero, O F, E-mail: o.f.herrero@hotmail.co [Conservatorio Superior de Musica ' Eduardo Martinez Torner' Corrada del Obispo s/n 33003 - Oviedo - Asturias (Spain)
2010-06-01
Music and Physics are very close because of the symmetry that appears in music. A periodic wave is what music really is, and there is a field of Physics devoted to waves researching. The different musical scales are the base of all kind of music. This article tries to show how this musical scales are made, how the consonance is the base of many of them and how symmetric they are.
Lie symmetries and superintegrability
International Nuclear Information System (INIS)
Nucci, M C; Post, S
2012-01-01
We show that a known superintegrable system in two-dimensional real Euclidean space (Post and Winternitz 2011 J. Phys. A: Math. Theor. 44 162001) can be transformed into a linear third-order equation: consequently we construct many autonomous integrals—polynomials up to order 18—for the same system. The reduction method and the connection between Lie symmetries and Jacobi last multiplier are used.
International Nuclear Information System (INIS)
Herrero, O F
2010-01-01
Music and Physics are very close because of the symmetry that appears in music. A periodic wave is what music really is, and there is a field of Physics devoted to waves researching. The different musical scales are the base of all kind of music. This article tries to show how this musical scales are made, how the consonance is the base of many of them and how symmetric they are.
Broken Stone Marker Construction%碎石桩施工
Institute of Scientific and Technical Information of China (English)
高瑞娥
2009-01-01
随着我国高速公路建设的加快,在高速公路的路基设计和施工中引入并使用碎石桩处理软土地基. 文章就结合碎石桩处理软土地基,浅谈碎石桩的施工过程和检测方法.%This paper unifies the broken stone marker processing soft soil ground, discusses the broken stone marker shallowly the construction pro-cess and the examination method.
International Nuclear Information System (INIS)
Elizalde, E.; Gavrilov, S.P.; Shil'nov, Yu.I.
2000-01-01
A four-fermion model with additional higher-derivative terms is investigated in an external electromagnetic field. The effective potential in the leading order of large-N expansion is calculated in external constant magnetic and electric fields. It is shown that, in contrast to the former results concerning the universal character of 'magnetic catalysis' in dynamical symmetry breaking, in the present higher-derivative model the magnetic field restores chiral symmetry broken initially on the tree level. Numerical results describing a second-order phase transition that accompanies the symmetry restoration at the quantum level are presented. (author)
General conditions for the PT symmetry of supersymmetric partner potentials
International Nuclear Information System (INIS)
Levai, G.
2004-01-01
Complete text of publication follows. A common feature of symmetries of quantum systems is that they restrict the form of the Hamiltonian, and consequently they also influence the structure of the energy spectrum. This is also the case with two symmetry concepts that are typically applied in non-relativistic quantum mechanics: supersymmetric quantum mechanics (SUSYQM) and PT symmetry. SUSYQM connects one-dimensional potentials pairwise via the relation V (±) (x) W 2 (x) ± dW/dx + ε, where ε is the factorization energy, V (-) (x) and V (+) (x) are the SUSY partner potentials, while W(x) is the superpotential. In the simplest case, when supersymmetry is unbroken, W(x) is defined in terms of the ground-state wavefunction of V (-) (x) as W(x) = - d/dx lnψ 0 (-) (x), and the factorization energy is chosen as ε E 0 (-) . Under these conditions the SUSY partner potentials possess the same energy levels, except that E 0 (-) is missing from the spectrum of V (+) (x), and the degenerate levels are connected by the SUSY ladder operators A = d/dx + W(x) and A † = - d/dx + W(x). The PT symmetry of a Hamiltonian prescribes its invariance under simultaneous space and time inversion, which boils down to the condition V (x) = V*(-x) in the case of one-dimensional potentials. The unusual feature of this new symmetry concept is that PT-symmetric potentials are complex in general, nevertheless, they possess real energy eigen-values, unless PT symmetry is spontaneously broken, in which case the energy spectrum consists of complex conjugate energy pairs. The interplay of these two symmetry concepts has been analyzed in a number of works, and it has been found that when V (-) (x) has unbroken PT symmetry, then the same applies to V (+) (x), while the spontaneous breakdown of the PT symmetry of V (-) (x) implies the manifest breakdown of the PT symmetry of V (+) (x). The factorization energy ε was found to be real in the former case, and imaginary in the latter one. The examples
Symmetry methods for option pricing
Davison, A. H.; Mamba, S.
2017-06-01
We obtain a solution of the Black-Scholes equation with a non-smooth boundary condition using symmetry methods. The Black-Scholes equation along with its boundary condition are first transformed into the one dimensional heat equation and an initial condition respectively. We then find an appropriate general symmetry generator of the heat equation using symmetries and the fundamental solution of the heat equation. The symmetry generator is chosen such that the boundary condition is left invariant; the symmetry can be used to solve the heat equation and hence the Black-Scholes equation.
Discrete gauge symmetries in discrete MSSM-like orientifolds
International Nuclear Information System (INIS)
Ibáñez, L.E.; Schellekens, A.N.; Uranga, A.M.
2012-01-01
Motivated by the necessity of discrete Z N symmetries in the MSSM to insure baryon stability, we study the origin of discrete gauge symmetries from open string sector U(1)'s in orientifolds based on rational conformal field theory. By means of an explicit construction, we find an integral basis for the couplings of axions and U(1) factors for all simple current MIPFs and orientifolds of all 168 Gepner models, a total of 32 990 distinct cases. We discuss how the presence of discrete symmetries surviving as a subgroup of broken U(1)'s can be derived using this basis. We apply this procedure to models with MSSM chiral spectrum, concretely to all known U(3)×U(2)×U(1)×U(1) and U(3)×Sp(2)×U(1)×U(1) configurations with chiral bi-fundamentals, but no chiral tensors, as well as some SU(5) GUT models. We find examples of models with Z 2 (R-parity) and Z 3 symmetries that forbid certain B and/or L violating MSSM couplings. Their presence is however relatively rare, at the level of a few percent of all cases.
Is the standard model saved asymptotically by conformal symmetry?
Gorsky, A.; Mironov, A.; Morozov, A.; Tomaras, T. N.
2015-03-01
It is pointed out that the top-quark and Higgs masses and the Higgs VEV with great accuracy satisfy the relations 4 m {/H 2} = 2 m {/T 2} = v 2, which are very special and reminiscent of analogous ones at Argyres-Douglas points with enhanced conformal symmetry. Furthermore, the RG evolution of the corresponding Higgs self-interaction and Yukawa couplings λ(0) = 1/8 and y(0) = 1 leads to the free-field stable point in the pure scalar sector at the Planck scale, also suggesting enhanced conformal symmetry. Thus, it is conceivable that the Standard Model is the low-energy limit of a distinct special theory with (super?) conformal symmetry at the Planck scale. In the context of such a "scenario," one may further speculate that the Higgs particle is the Goldstone boson of (partly) spontaneously broken conformal symmetry. This would simultaneously resolve the hierarchy and Landau pole problems in the scalar sector and would provide a nearly flat potential with two almost degenerate minima at the electroweak and Planck scales.
Tracing symmetries and their breakdown through phases of heterotic (2,2) compactifications
Energy Technology Data Exchange (ETDEWEB)
Blaszczyk, Michael [Johannes-Gutenberg-Universität,Staudingerweg 7, 55099 Mainz (Germany); Oehlmann, Paul-Konstantin [Bethe Center for Theoretical Physics, Physikalisches Institut der Universität Bonn,Nussallee 12, 53115 Bonn (Germany)
2016-04-12
We are considering the class of heterotic N=(2,2) Landau-Ginzburg orbifolds with 9 fields corresponding to A{sub 1}{sup 9} Gepner models. We classify all of its Abelian discrete quotients and obtain 152 inequivalent models closed under mirror symmetry with N=1,2 and 4 supersymmetry in 4D. We compute the full massless matter spectrum at the Fermat locus and find a universal relation satisfied by all models. In addition we give prescriptions of how to compute all quantum numbers of the 4D states including their discrete R-symmetries. Using mirror symmetry of rigid geometries we describe orbifold and smooth Calabi-Yau phases as deformations away from the Landau-Ginzburg Fermat locus in two explicit examples. We match the non-Fermat deformations to the 4D Higgs mechanism and study the conservation of R-symmetries. The first example is a ℤ{sub 3} orbifold on an E{sub 6} lattice where the R-symmetry is preserved. Due to a permutation symmetry of blow-up and torus Kähler parameters the R-symmetry stays conserved also in the smooth Calabi-Yau phase. In the second example the R-symmetry gets broken once we deform to the geometric ℤ{sub 3}×ℤ{sub 3,free} orbifold regime.
Tracing symmetries and their breakdown through phases of heterotic (2,2) compactifications
International Nuclear Information System (INIS)
Blaszczyk, Michael; Oehlmann, Paul-Konstantin
2016-01-01
We are considering the class of heterotic N=(2,2) Landau-Ginzburg orbifolds with 9 fields corresponding to A 1 9 Gepner models. We classify all of its Abelian discrete quotients and obtain 152 inequivalent models closed under mirror symmetry with N=1,2 and 4 supersymmetry in 4D. We compute the full massless matter spectrum at the Fermat locus and find a universal relation satisfied by all models. In addition we give prescriptions of how to compute all quantum numbers of the 4D states including their discrete R-symmetries. Using mirror symmetry of rigid geometries we describe orbifold and smooth Calabi-Yau phases as deformations away from the Landau-Ginzburg Fermat locus in two explicit examples. We match the non-Fermat deformations to the 4D Higgs mechanism and study the conservation of R-symmetries. The first example is a ℤ 3 orbifold on an E 6 lattice where the R-symmetry is preserved. Due to a permutation symmetry of blow-up and torus Kähler parameters the R-symmetry stays conserved also in the smooth Calabi-Yau phase. In the second example the R-symmetry gets broken once we deform to the geometric ℤ 3 ×ℤ 3,free orbifold regime.
Tracing symmetries and their breakdown through phases of heterotic (2,2) compactifications
Blaszczyk, Michael; Oehlmann, Paul-Konstantin
2016-04-01
We are considering the class of heterotic N=(2,2) Landau-Ginzburg orbifolds with 9 fields corresponding to A 1 9 Gepner models. We classify all of its Abelian discrete quotients and obtain 152 inequivalent models closed under mirror symmetry with N=1 , 2 and 4 supersymmetry in 4D. We compute the full massless matter spectrum at the Fermat locus and find a universal relation satisfied by all models. In addition we give prescriptions of how to compute all quantum numbers of the 4D states including their discrete R-symmetries. Using mirror symmetry of rigid geometries we describe orbifold and smooth Calabi-Yau phases as deformations away from the Landau-Ginzburg Fermat locus in two explicit examples. We match the non-Fermat deformations to the 4D Higgs mechanism and study the conservation of R-symmetries. The first example is a Z_3 orbifold on an E6 lattice where the R-symmetry is preserved. Due to a permutation symmetry of blow-up and torus Kähler parameters the R-symmetry stays conserved also in the smooth Calabi-Yau phase. In the second example the R-symmetry gets broken once we deform to the geometric Z_3× Z_{3,free} orbifold regime.
Symmetry-breaking solutions of the Hubbard model
International Nuclear Information System (INIS)
Kuzemsky, A.L.; )
1998-10-01
The problem of finding the ferromagnetic and antiferromagnetic ''broken symmetry'' solutions of the correlated lattice fermion models beyond the mean-field approximation has been investigated. The calculation of the quasiparticle excitation spectrum with damping for the single- and multi-orbital Hubbard model has been performed in the framework of the equation-of-motion method for two-time temperature Green's Functions within a non-perturbative approach. A unified scheme for the construction of Generalised Mean Fields (elastic scattering corrections) and self-energy (inelastic scattering) in terms of Dyson equation has been generalised in order to include the presence of the ''source fields''. The damping of quasiparticles, which reflects the interaction of the single-particle and collective degrees of freedom has been calculated. The ''broken symmetry'' dynamical solutions of the Hubbard model, which correspond to various types of itinerant antiferromagnetism have been discussed. This approach complements previous studies and clarifies the nature of the concepts of itinerant antiferromagnetism and ''spin-aligning field'' of correlated lattice fermions. (author)
Electroweak symmetry breaking studies at the pp colliders of the 1990's and beyond
International Nuclear Information System (INIS)
Chanowitz, M.S.
1989-01-01
Within the conventional framework of a spontaneously broken gauge theory, general principles establish that the electroweak symmetry is broken by a new force that may be weak with associated new quanta below 1 TeV or strong with quanta above 1 TeV. The SSC parameters, √s = 40 TeV and L = 10 33 cm/sup /minus/2/s/sup /minus/1/, define a minimal facility with assured capability to observe the signals of symmetry breaking by a strong force above 1 TeV. Foreseeable luminosity upgrades would not be able to compensate a much lower collider energy for these physics signals. If the strong WW scattering signal were seen at the SSC in the 1990's it would provide a clear imperative for a collider with the physics reach of the ELOISATRON to begin detailed studies of the new force and quanta early in the next century. 35 refs., 7 figs., 4 tabs
“Electroweak symmetry breaking: to Higgs or not to Higgs” (3/3)
CERN. Geneva
2009-01-01
How do elementary particles acquire their mass? What is making the photon different from the Z boson? In a word: How is electroweak symmetry broken? This is one of the pressing questions in particle physics that the LHC will answer soon. The aim of this lectures is, after briefly introducing SM physics and the conventional Higgs mechanism, to give a survey of recent attempts to go beyond a simple elementary Higgs. In particular, I will describe composite models (where the Higgs boson emerges from a strongly-interacting sector) and Higsless models. Distinctive signatures at the LHC are expected and will reveal the true nature of the electroweak symmetry sector.
“Electroweak symmetry breaking: to Higgs or not to Higgs” (2/3)
CERN. Geneva
2009-01-01
How do elementary particles acquire their mass? What is making the photon different from the Z boson? In a word: How is electroweak symmetry broken? This is one of the pressing questions in particle physics that the LHC will answer soon. The aim of this lectures is, after briefly introducing SM physics and the conventional Higgs mechanism, to give a survey of recent attempts to go beyond a simple elementary Higgs. In particular, I will describe composite models (where the Higgs boson emerges from a strongly-interacting sector) and Higsless models. Distinctive signatures at the LHC are expected and will reveal the true nature of the electroweak symmetry sector.
“Electroweak symmetry breaking: to Higgs or not to Higgs” (1/3)
CERN. Geneva
2009-01-01
How do elementary particles acquire their mass? What is making the photon different from the Z boson? In a word: How is electroweak symmetry broken? This is one of the pressing questions in particle physics that the LHC will answer soon. The aim of this lectures is, after briefly introducing SM physics and the conventional Higgs mechanism, to give a survey of recent attempts to go beyond a simple elementary Higgs. In particular, I will describe composite models (where the Higgs boson emerges from a strongly-interacting sector) and Higsless models. Distinctive signatures at the LHC are expected and will reveal the true nature of the electroweak symmetry sector.
Chiral dynamics and heavy quark symmetry in a solvable toy field-theoretic model
International Nuclear Information System (INIS)
Bardeen, W.A.; Hill, C.T.
1994-01-01
We study a solvable QCD-like toy theory, a generalization of the Nambu--Jona-Lasinio model, which implements chiral symmetries of light quarks and heavy quark symmetry. The chiral symmetric and chiral broken phases can be dynamically tuned. This implies a parity-doubled heavy-light meson system, corresponding to a (0 - ,1 - ) multiplet and a (0 + ,1 + ) heavy spin multiplet. Consequently the mass difference of the two multiplets is given by a Goldberger-Treiman relation and g A is found to be small. The Isgur-Wise function ξ(w), the decay constant f B , and other observables are studied
Factorizable S-matrix and symmetry operator with toroidal rapidity values
International Nuclear Information System (INIS)
Hu Zhanning; Hou Boyu
1992-01-01
The factorizable S-matrix was constructed and the symmetry operator which commutes with the S-metric and has a new form of 'co-product', the elements of which depend on the parameters defining the toroidal rapidity surface. By defining a new operator which commutes with the symmetry operator the Yang-Baxter equation can be obtained. Finally, the relation between the broken Z N -symmetric model and the chiral Potts model was expressed explicitly in the self-dual genus zero limit
Implications of horizontal symmetries on baryon number violation in supersymmetric models
International Nuclear Information System (INIS)
Ben-Hamo, V.; Nir, Y.
1994-08-01
The smallness of the quark and lepton parameters and the hierarchy between them could be the result of selection rules due to a horizontal symmetry broken by a small parameter. The same selection rules apply to baryon number violating terms. Consequently, the problem of baryon number violation in supersymmetry may be solved naturally, without invoking any especially-designed extra symmetry. This mechanism is efficient enough even for low-scale flavor physics. Proton decay is likely to be dominated by the modes K + ν-bar i or K o μ + (e + ), and may proceed at observable rates. (authors). 15 refs
Symmetry-adapted HAM/3 method and its application to some symmetric molecules
Directory of Open Access Journals (Sweden)
Narita Susumu
2004-01-01
Full Text Available The semiempirical HAM/3 method developed by Lindholm and coworkers about two decades ago has been known to have a deficiency that splits energies for the degenerate energy states. We have recently proposed a group-theoretical approach to remedy the internally broken symmetry of the HAM/3 Hamiltonians. In this paper, we present some results of its application to various small molecules with symmetry Td, C3v, and D3h. The proposed scheme gives correct degeneracy for these molecules.
Symmetry-adapted HAM/3 method and its application to some symmetric molecules
Narita, Susumu; Shibuya, Tai-ichi; Fujiwara, Fred Y.; Takahata, Yuji
2004-01-01
The semiempirical HAM/3 method developed by Lindholm and coworkers about two decades ago has been known to have a deficiency that splits energies for the degenerate energy states. We have recently proposed a group-theoretical approach to remedy the internally broken symmetry of the HAM/3 Hamiltonians. In this paper, we present some results of its application to various small molecules with symmetry Td, C3v, and D3h. The proposed scheme gives correct degeneracy for these molecules. O método...
Children and Broken Homes: Sources for the Teacher.
Bentley, Eloise
The depreciating attitude toward family life in our society has intensified in the past few years. It is not unusual to find substantial numbers of children in a first grade classroom who live in broken homes. Divorce is the answer for more young couples than ever before, and as a result the children involved must face growing up with a parent…
Enticing arsonists with broken windows and social disorder
Douglas S. Thomas; David T. Butry; Jeffrey P. Prestemon
2011-01-01
In criminology, it is well understood that indicators of urban decay, such as abandoned buildings littered with broken windows, provide criminals with signals identifying neighborhoods with lower crime detection and apprehension rates than better maintained neighborhoods. Whether it is the resident populationâs sense of apathy, lack of civic pride, or fear of...
Review of "Spend Smart: Fix Our Broken School Funding System"
Baker, Bruce
2011-01-01
ConnCAN's Spend Smart: "Fix Our Broken School Funding System" was released concurrently with a bill introduced in the Connecticut legislature, based on the principles outlined in the report. However, the report is of negligible value to the policy debate over Connecticut school finance because it provides little or no support for any of…
INFLUENCE OF BROKEN ROTOR BARS LOCATION IN THE ...
African Journals Online (AJOL)
2013-06-30
Jun 30, 2013 ... single-phase induction motor by general method coupling field and circuit equations. IEEE. Trans Magnetics 31(3): 1908-1911. [6] Zouzou S. E., Khelif S., Halem N., Sahraoui M, 2011. Analysis of induction motor with broken rotor bars using circuit-field coupled method. International conference on electric.
Broken Heart Syndrome – An intra operative complication
Directory of Open Access Journals (Sweden)
Zara Wani
2018-03-01
Full Text Available We report a case of Broken Heart Syndrome in a 56 year old Postmenopausal woman suffered while undergoing simple biopsy procedure for vocal cord polyp that lead to physical, mental and financial burden both for the patient as well as the doctors. A team of cardiologists based on clinical and echocardiographic findings made the diagnosis of this case.
Quantum diffusion in two-dimensional random systems with particle–hole symmetry
International Nuclear Information System (INIS)
Ziegler, K
2012-01-01
We study the scattering dynamics of an n-component spinor wavefunction in a random environment on a two-dimensional lattice. If the particle–hole symmetry of the Hamiltonian is spontaneously broken the dynamics of the quantum particles becomes diffusive on large scales. The latter is described by a non-interacting Grassmann field, indicating a special kind of asymptotic freedom on large scales in d = 2. (paper)
Time-reversal symmetry breaking in quantum billiards
Energy Technology Data Exchange (ETDEWEB)
Schaefer, Florian
2009-01-26
The present doctoral thesis describes experimentally measured properties of the resonance spectra of flat microwave billiards with partially broken timereversal invariance induced by an embedded magnetized ferrite. A vector network analyzer determines the complex scattering matrix elements. The data is interpreted in terms of the scattering formalism developed in nuclear physics. At low excitation frequencies the scattering matrix displays isolated resonances. At these the effect of the ferrite on isolated resonances (singlets) and pairs of nearly degenerate resonances (doublets) is investigated. The hallmark of time-reversal symmetry breaking is the violation of reciprocity, i.e. of the symmetry of the scattering matrix. One finds that reciprocity holds in singlets; it is violated in doublets. This is modeled by an effective Hamiltonian of the resonator. A comparison of the model to the data yields time-reversal symmetry breaking matrix elements in the order of the level spacing. Their dependence on the magnetization of the ferrite is understood in terms of its magnetic properties. At higher excitation frequencies the resonances overlap and the scattering matrix elements fluctuate irregularly (Ericson fluctuations). They are analyzed in terms of correlation functions. The data are compared to three models based on random matrix theory. The model by Verbaarschot, Weidenmueller and Zirnbauer describes time-reversal invariant scattering processes. The one by Fyodorov, Savin and Sommers achieves the same for systems with complete time-reversal symmetry breaking. An extended model has been developed that accounts for partial breaking of time-reversal invariance. This extended model is in general agreement with the data, while the applicability of the other two models is limited. The cross-correlation function between forward and backward reactions determines the time-reversal symmetry breaking matrix elements of the Hamiltonian to up to 0.3 mean level spacings. Finally
Time-reversal symmetry breaking in quantum billiards
International Nuclear Information System (INIS)
Schaefer, Florian
2009-01-01
The present doctoral thesis describes experimentally measured properties of the resonance spectra of flat microwave billiards with partially broken timereversal invariance induced by an embedded magnetized ferrite. A vector network analyzer determines the complex scattering matrix elements. The data is interpreted in terms of the scattering formalism developed in nuclear physics. At low excitation frequencies the scattering matrix displays isolated resonances. At these the effect of the ferrite on isolated resonances (singlets) and pairs of nearly degenerate resonances (doublets) is investigated. The hallmark of time-reversal symmetry breaking is the violation of reciprocity, i.e. of the symmetry of the scattering matrix. One finds that reciprocity holds in singlets; it is violated in doublets. This is modeled by an effective Hamiltonian of the resonator. A comparison of the model to the data yields time-reversal symmetry breaking matrix elements in the order of the level spacing. Their dependence on the magnetization of the ferrite is understood in terms of its magnetic properties. At higher excitation frequencies the resonances overlap and the scattering matrix elements fluctuate irregularly (Ericson fluctuations). They are analyzed in terms of correlation functions. The data are compared to three models based on random matrix theory. The model by Verbaarschot, Weidenmueller and Zirnbauer describes time-reversal invariant scattering processes. The one by Fyodorov, Savin and Sommers achieves the same for systems with complete time-reversal symmetry breaking. An extended model has been developed that accounts for partial breaking of time-reversal invariance. This extended model is in general agreement with the data, while the applicability of the other two models is limited. The cross-correlation function between forward and backward reactions determines the time-reversal symmetry breaking matrix elements of the Hamiltonian to up to 0.3 mean level spacings. Finally
Greene, Brian R
1997-01-01
Mirror symmetry has undergone dramatic progress during the last five years. Tremendous insight has been gained on a number of key issues. This volume surveys these results. Some of the contributions in this work have appeared elsewhere, while others were written specifically for this collection. The areas covered are organized into 4 sections, and each presents papers by both physicists and mathematicians. This volume collects the most important developments that have taken place in mathematical physics since 1991. It is an essential reference tool for both mathematics and physics libraries and for students of physics and mathematics.
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...... 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...
Farmer, David W
1995-01-01
In most mathematics textbooks, the most exciting part of mathematics-the process of invention and discovery-is completely hidden from the reader. The aim of Groups and Symmetry is to change all that. By means of a series of carefully selected tasks, this book leads readers to discover some real mathematics. There are no formulas to memorize; no procedures to follow. The book is a guide: Its job is to start you in the right direction and to bring you back if you stray too far. Discovery is left to you. Suitable for a one-semester course at the beginning undergraduate level, there are no prerequ
Yale, Paul B
2012-01-01
This book is an introduction to the geometry of Euclidean, affine, and projective spaces with special emphasis on the important groups of symmetries of these spaces. The two major objectives of the text are to introduce the main ideas of affine and projective spaces and to develop facility in handling transformations and groups of transformations. Since there are many good texts on affine and projective planes, the author has concentrated on the n-dimensional cases.Designed to be used in advanced undergraduate mathematics or physics courses, the book focuses on ""practical geometry,"" emphasi
Applications of chiral symmetry
International Nuclear Information System (INIS)
Pisarski, R.D.
1995-03-01
The author discusses several topics in the applications of chiral symmetry at nonzero temperature. First, where does the rho go? The answer: up. The restoration of chiral symmetry at a temperature T χ implies that the ρ and a 1 vector mesons are degenerate in mass. In a gauged linear sigma model the ρ mass increases with temperature, m ρ (T χ ) > m ρ (0). The author conjectures that at T χ the thermal ρ - a 1 , peak is relatively high, at about ∼1 GeV, with a width approximately that at zero temperature (up to standard kinematic factors). The ω meson also increases in mass, nearly degenerate with the ρ, but its width grows dramatically with temperature, increasing to at least ∼100 MeV by T χ . The author also stresses how utterly remarkable the principle of vector meson dominance is, when viewed from the modern perspective of the renormalization group. Secondly, he discusses the possible appearance of disoriented chiral condensates from open-quotes quenchedclose quotes heavy ion collisions. It appears difficult to obtain large domains of disoriented chiral condensates in the standard two flavor model. This leads to the last topic, which is the phase diagram for QCD with three flavors, and its proximity to the chiral critical point. QCD may be very near this chiral critical point, and one might thereby generated large domains of disoriented chiral condensates
Bootstrap Dynamical Symmetry Breaking
Directory of Open Access Journals (Sweden)
Wei-Shu Hou
2013-01-01
Full Text Available Despite the emergence of a 125 GeV Higgs-like particle at the LHC, we explore the possibility of dynamical electroweak symmetry breaking by strong Yukawa coupling of very heavy new chiral quarks Q . Taking the 125 GeV object to be a dilaton with suppressed couplings, we note that the Goldstone bosons G exist as longitudinal modes V L of the weak bosons and would couple to Q with Yukawa coupling λ Q . With m Q ≳ 700 GeV from LHC, the strong λ Q ≳ 4 could lead to deeply bound Q Q ¯ states. We postulate that the leading “collapsed state,” the color-singlet (heavy isotriplet, pseudoscalar Q Q ¯ meson π 1 , is G itself, and a gap equation without Higgs is constructed. Dynamical symmetry breaking is affected via strong λ Q , generating m Q while self-consistently justifying treating G as massless in the loop, hence, “bootstrap,” Solving such a gap equation, we find that m Q should be several TeV, or λ Q ≳ 4 π , and would become much heavier if there is a light Higgs boson. For such heavy chiral quarks, we find analogy with the π − N system, by which we conjecture the possible annihilation phenomena of Q Q ¯ → n V L with high multiplicity, the search of which might be aided by Yukawa-bound Q Q ¯ resonances.
Directory of Open Access Journals (Sweden)
Angel Garrido
2011-01-01
Full Text Available In this paper, we analyze a few interrelated concepts about graphs, such as their degree, entropy, or their symmetry/asymmetry levels. These concepts prove useful in the study of different types of Systems, and particularly, in the analysis of Complex Networks. A System can be defined as any set of components functioning together as a whole. A systemic point of view allows us to isolate a part of the world, and so, we can focus on those aspects that interact more closely than others. Network Science analyzes the interconnections among diverse networks from different domains: physics, engineering, biology, semantics, and so on. Current developments in the quantitative analysis of Complex Networks, based on graph theory, have been rapidly translated to studies of brain network organization. The brain's systems have complex network features—such as the small-world topology, highly connected hubs and modularity. These networks are not random. The topology of many different networks shows striking similarities, such as the scale-free structure, with the degree distribution following a Power Law. How can very different systems have the same underlying topological features? Modeling and characterizing these networks, looking for their governing laws, are the current lines of research. So, we will dedicate this Special Issue paper to show measures of symmetry in Complex Networks, and highlight their close relation with measures of information and entropy.
On natural hierarchy in dynamically broken gauge models
International Nuclear Information System (INIS)
Frere, J.M.
1980-01-01
A model based on dynamical symmetry breaking provides a naturally large 'mass hierarchy'. Few fermions are needed at intermediate energies, and asymptotic freedom of usual interactions is therefore not imperiled. (orig.)
Wilczek, Frank
2004-01-01
Powerful symmetry principles have guided physicists in their quest for nature's fundamental laws. The successful gauge theory of electroweak interactions postulates a more extensive symmetry for its equations than are manifest in the world (8 pages) Powerful symmetry principles have guided physicists in their quest for nature's fundamental laws. The successful gauge theory of electroweak interactions postulates a more extensive symmetry for its equations than are manifest in the world. The discrepancy is ascribed to a pervasive symmetry-breaking field, which fills all space uniformly, rendering the Universe a sort of exotic superconductor. So far, the evidence for these bold ideas is indirect. But soon the theory will undergo a critical test depending on whether the quanta of this symmetry-breaking field, the so-called Higgs particles, are produced at the Large Hadron Collider (due to begin operation in 2007).
Symmetry of crystals and molecules
Ladd, Mark
2014-01-01
This book successfully combines a thorough treatment of molecular and crystalline symmetry with a simple and informal writing style. By means of familiar examples the author helps to provide the reader with those conceptual tools necessary for the development of a clear understanding of what are often regarded as 'difficult' topics. Christopher Hammond, University of Leeds This book should tell you everything you need to know about crystal and molecular symmetry. Ladd adopts an integrated approach so that the relationships between crystal symmetry, molecular symmetry and features of chemical interest are maintained and reinforced. The theoretical aspects of bonding and symmetry are also well represented, as are symmetry-dependent physical properties and the applications of group theory. The comprehensive coverage will make this book a valuable resource for a broad range of readers.
Trieste lectures on mirror symmetry
Energy Technology Data Exchange (ETDEWEB)
Hori, K [Department of Physics and Department of Mathematics, University of Toronto, Toronto, Ontario (Canada)
2003-08-15
These are pedagogical lectures on mirror symmetry given at the Spring School in ICTP, Trieste, March 2002. The focus is placed on worldsheet descriptions of the physics related to mirror symmetry. We start with the introduction to general aspects of (2,2) supersymmetric field theories in 1 + 1 dimensions. We next move on to the study and applications of linear sigma model. Finally, we provide a proof of mirror symmetry in a class of models. (author)
Quantum symmetry in quantum theory
International Nuclear Information System (INIS)
Schomerus, V.
1993-02-01
Symmetry concepts have always been of great importance for physical problems like explicit calculations, classification or model building. More recently, new 'quantum symmetries' ((quasi) quantum groups) attracted much interest in quantum theory. It is shown that all these quantum symmetries permit a conventional formulation as symmetry in quantum mechanics. Symmetry transformations can act on the Hilbert space H of physical states such that the ground state is invariant and field operators transform covariantly. Models show that one must allow for 'truncation' in the tensor product of representations of a quantum symmetry. This means that the dimension of the tensor product of two representations of dimension σ 1 and σ 2 may be strictly smaller than σ 1 σ 2 . Consistency of the transformation law of field operators local braid relations leads us to expect, that (weak) quasi quantum groups are the most general symmetries in local quantum theory. The elements of the R-matrix which appears in these local braid relations turn out to be operators on H in general. It will be explained in detail how examples of field algebras with weak quasi quantum group symmetry can be obtained. Given a set of observable field with a finite number of superselection sectors, a quantum symmetry together with a complete set of covariant field operators which obey local braid relations are constructed. A covariant transformation law for adjoint fields is not automatic but will follow when the existence of an appropriate antipode is assumed. At the example of the chiral critical Ising model, non-uniqueness of the quantum symmetry will be demonstrated. Generalized quantum symmetries yield examples of gauge symmetries in non-commutative geometry. Quasi-quantum planes are introduced as the simplest examples of quasi-associative differential geometry. (Weak) quasi quantum groups can act on them by generalized derivations much as quantum groups do in non-commutative (differential-) geometry
Spontaneous symmetry breaking and response functions
International Nuclear Information System (INIS)
Beraudo, A.; De Pace, A.; Martini, M.; Molinari, A.
2005-01-01
We study the quantum phase transition occurring in an infinite homogeneous system of spin 1/2 fermions in a non-relativistic context. As an example we consider neutrons interacting through a simple spin-spin Heisenberg force. The two critical values of the coupling strength-signaling the onset into the system of a finite magnetization and of the total magnetization, respectively-are found and their dependence upon the range of the interaction is explored. The spin response function of the system in the region where the spin-rotational symmetry is spontaneously broken is also studied. For a ferromagnetic interaction the spin response along the direction of the spontaneous magnetization occurs in the particle-hole continuum and displays, for not too large momentum transfers, two distinct peaks. The response along the direction orthogonal to the spontaneous magnetization displays instead, beyond a softened and depleted particle-hole continuum, a collective mode to be identified with a Goldstone boson of type II. Notably, the random phase approximation on a Hartree-Fock basis accounts for it, in particular for its quadratic-close to the origin-dispersion relation. It is shown that the Goldstone boson contributes to the saturation of the energy-weighted sum rule for ∼25% when the system becomes fully magnetized (that is in correspondence of the upper critical value of the interaction strength) and continues to grow as the interaction strength increases
An introduction to Yangian symmetries
International Nuclear Information System (INIS)
Bernard, D.
1992-01-01
Some aspects of the quantum Yangians as symmetry algebras of two-dimensional quantum field theories are reviewed. They include two main issues: the first is the classical Heisenberg model, covering non-Abelian symmetries, generators of the symmetries and the semi-classical Yangians, an alternative presentation of the semi-classical Yangians, digression on Poisson-Lie groups. The second is the quantum Heisenberg chain, covering non-Abelian symmetries and the quantum Yangians, the transfer matrix and an alternative presentation of the Yangians, digression on the double Yangians. (K.A.) 15 refs
Killing symmetries in neutron transport
International Nuclear Information System (INIS)
Lukacs, B.; Racz, A.
1992-10-01
Although inside the reactor zone there is no exact continuous spatial symmetry, in certain configurations neutron flux distribution is close to a symmetrical one. In such cases the symmetrical solution could provide a good starting point to determine the non-symmetrical power distribution. All possible symmetries are determined in the 3-dimensional Euclidean space, and the form of the transport equation is discussed in such a coordinate system which is adapted to the particular symmetry. Possible spontaneous symmetry breakings are pointed out. (author) 6 refs
The conservation of orbital symmetry
Woodward, R B
2013-01-01
The Conservation of Orbital Symmetry examines the principle of conservation of orbital symmetry and its use. The central content of the principle was that reactions occur readily when there is congruence between orbital symmetry characteristics of reactants and products, and only with difficulty when that congruence does not obtain-or to put it more succinctly, orbital symmetry is conserved in concerted reaction. This principle is expected to endure, whatever the language in which it may be couched, or whatever greater precision may be developed in its application and extension. The book ope
Spontaneous symmetry breaking in ΡΤ symmetric systems with nonlinear damping
International Nuclear Information System (INIS)
Karthiga, S.; Chandrasekar, V.K.; Senthilvelan, M.; Lakshmanan, M.
2016-01-01
In this talk, we discuss the remarkable role of position dependent damping in determining the parametric regions of symmetry breaking in nonlinear ΡΤ -symmetric systems. We illustrate the nature of ΡΤ-symmetry preservation and breaking with reference to a remarkable integrable scalar nonlinear system. In the two dimensional cases of such position dependent damped systems, we unveil the existence of a class of novel bi-ΡΤ -symmetric systems which have two fold ΡΤ symmetries. We discuss the dynamics of these systems and show how symmetry breaking occurs, that is whether the symmetry breaking of the two ΡΤ symmetries occurs in pair or occurs one by one. The addition of linear damping in these nonlinearly damped systems induces competition between the two types of damping. This competition results in a ΡΤ phase transition in which the ΡΤ symmetry is broken for lower loss/gain strength and is restored by increasing the loss/gain strength. We also show that by properly designing the form of the position dependent damping, we can tailor the ΡΤ-symmetric regions of the system. (author)
Particle-Hole Symmetry Breaking in the Pseudogap State of Bi2201
Energy Technology Data Exchange (ETDEWEB)
Hashimoto, M.; /SIMES, Stanford /Stanford U., Geballe Lab. /LBNL, ALS; He, R.-H.; /aff SIMES, Stanford /Stanford U., Geballe Lab.; Tanaka, K.; /aff SIMES, Stanford /Stanford U., Geballe Lab. /LBNL, ALS /Osaka U.; Testaud, J.P.; /SIMES, Stanford /Stanford U., Geballe Lab. /LBNL, ALS; Meevasana1, W.; Moore, R.G.; Lu, D.H.; /SIMES, Stanford /Stanford U., Geballe Lab.; Yao, H.; /SIMES, Stanford; Yoshida, Y.; Eisaki, H.; /AIST, Tsukuba; Devereaux, T.P.; /SIMES, Stanford /Stanford U., Geballe Lab.; Hussain, Z.; /LBNL, ALS; Shen, Z.-X.; /SIMES, Stanford /Stanford U., Geballe Lab.
2011-08-19
In conventional superconductors, a gap exists in the energy absorption spectrum only below the transition temperature (T{sub c}), corresponding to the energy price to pay for breaking a Cooper pair of electrons. In high-T{sub c} cuprate superconductors above T{sub c}, an energy gap called the pseudogap exists, and is controversially attributed either to pre-formed superconducting pairs, which would exhibit particle-hole symmetry, or to competing phases which would typically break it. Scanning tunnelling microscopy (STM) studies suggest that the pseudogap stems from lattice translational symmetry breaking and is associated with a different characteristic spectrum for adding or removing electrons (particle-hole asymmetry). However, no signature of either spatial or energy symmetry breaking of the pseudogap has previously been observed by angle-resolved photoemission spectroscopy (ARPES). Here we report ARPES data from Bi2201 which reveals both particle-hole symmetry breaking and dramatic spectral broadening indicative of spatial symmetry breaking without long range order, upon crossing through T* into the pseudogap state. This symmetry breaking is found in the dominant region of the momentum space for the pseudogap, around the so-called anti-node near the Brillouin zone boundary. Our finding supports the STM conclusion that the pseudogap state is a broken-symmetry state that is distinct from homogeneous superconductivity.
Xiao, R. C.; Cheung, C. H.; Gong, P. L.; Lu, W. J.; Si, J. G.; Sun, Y. P.
2018-06-01
k paths exactly with symmetry allow to find triply degenerate points (TDPs) in band structures. The paths that host the type-II Dirac points in PtSe2 family materials also have the spatial symmetry. However, due to Kramers degeneracy (the systems have both inversion symmetry and time reversal symmetry), the crossing points in them are Dirac ones. In this work, based on symmetry analysis, first-principles calculations, and method, we predict that PtSe2 family materials should undergo topological transitions if the inversion symmetry is broken, i.e. the Dirac fermions in PtSe2 family materials split into TDPs in PtSeTe family materials (PtSSe, PtSeTe, and PdSeTe) with orderly arranged S/Se (Se/Te). It is different from the case in high-energy physics that breaking inversion symmetry I leads to the splitting of Dirac fermion into Weyl fermions. We also address a possible method to achieve the orderly arranged in PtSeTe family materials in experiments. Our study provides a real example that Dirac points transform into TDPs, and is helpful to investigate the topological transition between Dirac fermions and TDP fermions.
Duality transformation of a spontaneously broken gauge theory
International Nuclear Information System (INIS)
Mizrachi, L.
1981-04-01
Duality transformation for a spontaneously broken gauge theory is constructed in the CDS gauge (xsub(μ)Asub(μ)sup(a)=0). The dual theory is expressed in terms of dual potentials which satisfy the same gauge condition, but with g→ 1 /g. Generally the theory is not self dual but in the weak coupling region (small g), self duality is found for the subgroup which is not spontaneously broken or in regions where monopoles and vortices are concentrated (in agreement with t'Hooft's ideas that monopoles and vortices in the Georgi-Glashow model make it self dual). In the strong coupling regime a systematic strong coupling expansion can be written. For this region the dual theory is generally not local gauge invariant, but it is invariant under global gauge transformations. (author)
Theoretical studies of radiative properties of broken clouds
International Nuclear Information System (INIS)
Titov, G.A.
1994-01-01
One of the three goals of the Atmospheric Radiation Measurement (ARM) Program is to improve the quality of radiation models under clear sky, homogeneous cloud, and broken cloud conditions. This report is concerned with the development of the theory of radiation transfer in the broken clouds. Our approach is based on a stochastic description of the interaction between the radiation and cloud field with stochastic geometry; In the following, we discuss (1) the mean radiation fluxes in the near IR spectral range 2.7 to 3.2 μm; (2) the influence of random geometry of individual cumulus clouds on the mean fluxes of visible solar radiation; (3) the equations of the mean radiance in the statistically inhomogeneous cloud fields
QCD-instantons and conformal space-time inversion symmetry
International Nuclear Information System (INIS)
Klammer, D.
2008-04-01
In this paper, we explore the appealing possibility that the strong suppression of large-size QCD instantons - as evident from lattice data - is due to a surviving conformal space-time inversion symmetry. This symmetry is both suggested from the striking invariance of highquality lattice data for the instanton size distribution under inversion of the instanton size ρ→(left angle ρ right angle 2 )/(ρ) and from the known validity of space-time inversion symmetry in the classical instanton sector. We project the instanton calculus onto the four-dimensional surface of a five-dimensional sphere via conformal stereographic mapping, before investigating conformal inversion. This projection to a compact, curved geometry is both to avoid the occurence of divergences and to introduce the average instanton size left angle ρ right angle from the lattice data as a new length scale. The average instanton size is identified with the radius b of this 5d-sphere and acts as the conformal inversion radius. For b= left angle ρ right angle, our corresponding results are almost perfectly symmetric under space-time inversion and in good qualitative agreement with the lattice data. For (ρ)/(b)→0 we recover the familiar results of instanton perturbation theory in flat 4d-space. Moreover, we illustrate that a (weakly broken) conformal inversion symmetry would have significant consequences for QCD beyond instantons. As a further successful test for inversion symmetry, we present striking implications for another instanton dominated lattice observable, the chirality-flip ratio in the QCD vacuum. (orig.)
Greiner, Walter
1989-01-01
"Quantum Dynamics" is a major survey of quantum theory based on Walter Greiner's long-running and highly successful courses at the University of Frankfurt. The key to understanding in quantum theory is to reinforce lecture attendance and textual study by working through plenty of representative and detailed examples. Firm belief in this principle led Greiner to develop his unique course and to transform it into a remarkable and comprehensive text. The text features a large number of examples and exercises involving many of the most advanced topics in quantum theory. These examples give practical and precise demonstrations of how to use the often subtle mathematics behind quantum theory. The text is divided into five volumes: Quantum Mechanics I - An Introduction, Quantum Mechanics II - Symmetries, Relativistic Quantum Mechanics, Quantum Electrodynamics, Gauge Theory of Weak Interactions. These five volumes take the reader from the fundamental postulates of quantum mechanics up to the latest research in partic...
Symmetries of cluster configurations
International Nuclear Information System (INIS)
Kramer, P.
1975-01-01
A deeper understanding of clustering phenomena in nuclei must encompass at least two interrelated aspects of the subject: (A) Given a system of A nucleons with two-body interactions, what are the relevant and persistent modes of clustering involved. What is the nature of the correlated nucleon groups which form the clusters, and what is their mutual interaction. (B) Given the cluster modes and their interaction, what systematic patterns of nuclear structure and reactions emerge from it. Are there, for example, families of states which share the same ''cluster parents''. Which cluster modes are compatible or exclude each other. What quantum numbers could characterize cluster configurations. There is no doubt that we can learn a good deal from the experimentalists who have discovered many of the features relevant to aspect (B). Symmetries specific to cluster configurations which can throw some light on both aspects of clustering are discussed
Broken Esophageal Stent Successfully Treated by Interventional Radiology Technique
International Nuclear Information System (INIS)
Zelenak, Kamil; Mistuna, Dusan; Lucan, Jaroslav; Polacek, Hubert
2010-01-01
Esophageal stent fractures occur quite rarely. A 61-year-old male patient was previously treated for rupture of benign stenosis, occurring after dilatation, by implanting an esophageal stent. However, a year after implantation, the patient suffered from dysphagia caused by the broken esophageal stent. He was treated with the interventional radiology technique, whereby a second implantation of the esophageal stent was carried out quite successfully.
Octonionic gauge theory from spontaneously broken SO(8)
International Nuclear Information System (INIS)
Lassig, C.C.; Joshi, G.C.
1995-01-01
An attempt is made to construct a gauge theory based on a bimodular representation of the octonion algebra, the non associativity of which is manifested as a non-closure of the bimodule algebra. It is found that this fact leads to gauge-noninvariance of the theory. However, the bimodule algebra can be embedded in SO(8), the gauge theory of which can be broken down to give a massless SO(7) theory together with a massive octonionic gauge theory. 7 refs
Mass Formulae for Broken Supersymmetry in Curved Space-Time
Ferrara, Sergio
2016-01-01
We derive the mass formulae for ${\\cal N}=1$, $D=4$ matter-coupled Supergravity for broken (and unbroken) Supersymmetry in curved space-time. These formulae are applicable to de Sitter configurations as is the case for inflation. For unbroken Supersymmetry in anti-de Sitter (AdS) one gets the mass relations modified by the AdS curvature. We compute the mass relations both for the potential and its derivative non-vanishing.
Determining reactor fuel elements broken by Cerenkov counting
International Nuclear Information System (INIS)
Guo Juhao; Dong Shiyuan; Feng Yuying
1996-01-01
The basis and method of determining fuel elements broken in a reactor by Cerenkov counting measured with liquid scintillation spectrometer are introduced. The radioactive characteristic of the radiation nuclides generating Cherenkov radiation in the primary water of 200 MW nuclear district heating reactor is analyzed. The activity of the activation products in the primary water and the fission products in the fuel elements are calculated. A feasibility of Cerenkov counting measure was analyzed. This method is simple and quick
Mental Suffering in Protracted Political Conflict: Feeling Broken or Destroyed.
Barber, Brian K; McNeely, Clea A; El Sarraj, Eyad; Daher, Mahmoud; Giacaman, Rita; Arafat, Cairo; Barnes, William; Abu Mallouh, Mohammed
2016-01-01
This mixed-methods exploratory study identified and then developed and validated a quantitative measure of a new construct of mental suffering in the occupied Palestinian territory: feeling broken or destroyed. Group interviews were conducted in 2011 with 68 Palestinians, most aged 30-40, in the West Bank, East Jerusalem, and the Gaza Strip to discern local definitions of functioning. Interview participants articulated of a type of suffering not captured in existing mental health instruments used in regions of political conflict. In contrast to the specific difficulties measured by depression and PTSD (sleep, appetite, energy, flashbacks, avoidance, etc.), participants elaborated a more existential form of mental suffering: feeling that one's spirit, morale and/or future was broken or destroyed, and emotional and psychological exhaustion. Participants articulated these feelings when describing the rigors of the political and economic contexts in which they live. We wrote survey items to capture these sentiments and administered these items-along with standard survey measures of mental health-to a representative sample of 1,778 32-43 year olds in the occupied Palestinian territory. The same survey questions also were administered to a representative subsample (n = 508) six months earlier, providing repeated measures of the construct. Across samples and time, the feeling broken or destroyed scale: 1) comprised a separate factor in exploratory factor analyses, 2) had high inter-item consistency, 3) was reported by both genders and in all regions, 4) showed discriminate validity via moderate correlations with measures of feelings of depression and trauma-related stress, and 5) was more commonly experienced than either feelings of depression or trauma-related stress. Feeling broken or destroyed can be reliably measured and distinguished from conventional measures of mental health. Such locally grounded and contextualized measures should be identified and included in
International Nuclear Information System (INIS)
Lipkin, H.J.
1980-09-01
Nonleptonic weak decays of strange hadrons are complicated by the interplay of weak and strong interactions. Models based either on symmetry properties or on the selection of certain types of diagrams are both open to criticism. The symmetries used are all broken in strong interactions, and the selection of some diagrams and neglect of others is never seriously justified. Furthermore, the number of related decays of strange hadrons is small, so that experimental data are insufficient for singificant tests of phenomenological models with a few free parameters. The discovery of charmed particles with many open channels for nonleptonic decays has provided a new impetus for a theoretical understanding of these processes. The GIM current provides a well defined weak hamiltonian, which can justifiably be used to first order. The QCD approach to strong interactions gives flavor-indpendent couplings and flavor symmetry broken only by quark masses. In a model with n generations of quarks and 2n flavors, a flavor symmetry group SU(2n) can be defined which is broken only by H/sub weak/ and the quark masses.Here again, the same two approaches by symmetry and dynamics have been used. But both types of treatment tend to consider only the symmetry properties or dominant diagrams of the weak interaction, including some subtle effects, while overlooking rather obvious effects of strong interactions
Perilaku Komunikasi antara Guru dengan Siswa Broken Home
Directory of Open Access Journals (Sweden)
Emilsyah Nur
2017-12-01
Full Text Available Penelitian yang dilakukan merupakan penelitian kualitatif yang menggunakan beberapa informan sebagai narasumber untuk menjawab permasalahan tentang opini publik terhadap komunikasi interpersonal dalam mengatasi orang tua broken home. Hasil penelitian menunjukkan bahwa perilaku komunikasi siswa broken home di sekolah belum sepenuhnya efektif. Hal ini disebabkan oleh: intensitas komunikasi antara orang tua dan anak yang masih kurang sehingga anak enggan untuk terbuka kepada orang tuanya mengenai prestasi belajar. Kurangnya dukungan, rasa empati serta sikap positif yang diberikan orang tua kepada anak juga mempengaruhi hubungan interpersonal diantara orang tua dan anak yang menyebabkan anak lebih terbuka kepada teman atau kerabatnya daripada orang tuanya sendiri.Kesetaraan antara orang tua dan anak masih kurang. Perilaku komunikasi yang demikian sangat berpengaruh terhadap perilaku anak di sekolah. Beberapa faktor yang menghambat prilaku komunikasi siswa broken home diantaranya yaitu orang tua yang kurang bisa membagi waktu antara pekerjaan dan memberikan perhatian kepada anak di rumah sehingga komunikasi dengan anak tidak berjalan dengan lancar, sikap acuh tak acuh yang ditunjukkan orang tua membuat anak menjauhkan diri dan tidak terbuka kepada orang tua dan ketidakterbukaan siswa terhadap Guru.
Broken instrument retrieval with indirect ultrasonics in a primary molar.
Pk, Musale; Sc, Kataria; As, Soni
2016-02-01
The separation of a file during pulpectomy is a rare incident in primary teeth due to inherently wider and relatively straighter root canals. A broken instrument hinders the clinician from optimal preparation and obturation of the root canal system invariably leading to failure, although in such teeth, an extraction followed by suitable space maintenance is considered as the treatment of choice. This case report demonstrates successful nonsurgical retrieval of a separated H file fragment in 84. A 7-year-old girl was referred to the Department of Paedodontics and Preventive Dentistry for endodontic management of a primary tooth 84 with a dento-alveolar abscess. Her medical history was noncontributory. After diagnosing a broken H file in the mesio-lingual canal, the tooth was endodontically treated in two appointments. At the first session, a broken file was successfully retrieved after using low intensity ultrasonic vibrations through a DG 16 endodontic explorer viewed under an operating microscope. After abscess resolution, Vitapex root canal obturation with a preformed metal crown cementation was completed at a second session. The patient was recalled at 3, 6, 12 and 15 month interval and reported to be clinically asymptomatic and radiographically with complete furcal healing. Integration of microscopes and ultrasonics in paediatric dental practice has made it possible to save such teeth with a successful outcome. Favourable location of the separated file, relatively straighter root canal system and patient cooperation resulted in successful nonsurgical management in this case.
Symmetry chains and adaptation coefficients
International Nuclear Information System (INIS)
Fritzer, H.P.; Gruber, B.
1985-01-01
Given a symmetry chain of physical significance it becomes necessary to obtain states which transform properly with respect to the symmetries of the chain. In this article we describe a method which permits us to calculate symmetry-adapted quantum states with relative ease. The coefficients for the symmetry-adapted linear combinations are obtained, in numerical form, in terms of the original states of the system and can thus be represented in the form of numerical tables. In addition, one also obtains automatically the matrix elements for the operators of the symmetry groups which are involved, and thus for any physical operator which can be expressed either as an element of the algebra or of the enveloping algebra. The method is well suited for computers once the physically relevant symmetry chain, or chains, have been defined. While the method to be described is generally applicable to any physical system for which semisimple Lie algebras play a role we choose here a familiar example in order to illustrate the method and to illuminate its simplicity. We choose the nuclear shell model for the case of two nucleons with orbital angular momentum l = 1. While the states of the entire shell transform like the smallest spin representation of SO(25) we restrict our attention to its subgroup SU(6) x SU(2)/sub T/. We determine the symmetry chains which lead to total angular momentum SU(2)/sub J/ and obtain the symmetry-adapted states for these chains
Collective states and crossing symmetry
International Nuclear Information System (INIS)
Heiss, W.D.
1977-01-01
Collective states are usually described in simple terms but with the use of effective interactions which are supposed to contain more or less complicated contributions. The significance of crossing symmetry is discussed in this connection. Formal problems encountered in the attempts to implement crossing symmetry are pointed out
Singlets of fermionic gauge symmetries
Bergshoeff, E.A.; Kallosh, R.E.; Rahmanov, M.A.
1989-01-01
We investigate under which conditions singlets of fermionic gauge symmetries which are "square roots of gravity" can exist. Their existence is non-trivial because there are no fields neutral in gravity. We tabulate several examples of singlets of global and local supersymmetry and Îº-symmetry and
Symmetry guide to ferroaxial transitions
Czech Academy of Sciences Publication Activity Database
Hlinka, Jiří; Přívratská, J.; Ondrejkovič, Petr; Janovec, Václav
2016-01-01
Roč. 116, č. 17 (2016), 1-6, č. článku 177602. ISSN 0031-9007 R&D Projects: GA ČR GA15-04121S Institutional support: RVO:68378271 Keywords : symmetry * symmetry breaking * ferroaxial Transitions * property tensors * Aizu species Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 8.462, year: 2016
Spontaneous SUSY breaking without R symmetry in supergravity
Maekawa, Nobuhiro; Omura, Yuji; Shigekami, Yoshihiro; Yoshida, Manabu
2018-03-01
We discuss spontaneous supersymmetry (SUSY) breaking in a model with an anomalous U (1 )A symmetry. In this model, the size of the each term in the superpotential is controlled by the U (1 )A charge assignment and SUSY is spontaneously broken via the Fayet-Iliopoulos of U (1 )A at the metastable vacuum. In the global SUSY analysis, the gaugino masses become much smaller than the sfermion masses, because an approximate R symmetry appears at the SUSY breaking vacuum. In this paper, we show that gaugino masses can be as large as gravitino mass, taking the supergravity effect into consideration. This is because the R symmetry is not imposed so that the constant term in the superpotential, which is irrelevant to the global SUSY analysis, largely contributes to the soft SUSY breaking terms in the supergravity. As the mediation mechanism, we introduce the contributions of the field not charged under U (1 )A and the moduli field to cancel the anomaly of U (1 )A. We comment on the application of our SUSY breaking scenario to the grand unified theory.
Composite symmetry-protected topological order and effective models
Nietner, A.; Krumnow, C.; Bergholtz, E. J.; Eisert, J.
2017-12-01
Strongly correlated quantum many-body systems at low dimension exhibit a wealth of phenomena, ranging from features of geometric frustration to signatures of symmetry-protected topological order. In suitable descriptions of such systems, it can be helpful to resort to effective models, which focus on the essential degrees of freedom of the given model. In this work, we analyze how to determine the validity of an effective model by demanding it to be in the same phase as the original model. We focus our study on one-dimensional spin-1 /2 systems and explain how nontrivial symmetry-protected topologically ordered (SPT) phases of an effective spin-1 model can arise depending on the couplings in the original Hamiltonian. In this analysis, tensor network methods feature in two ways: on the one hand, we make use of recent techniques for the classification of SPT phases using matrix product states in order to identify the phases in the effective model with those in the underlying physical system, employing Künneth's theorem for cohomology. As an intuitive paradigmatic model we exemplify the developed methodology by investigating the bilayered Δ chain. For strong ferromagnetic interlayer couplings, we find the system to transit into exactly the same phase as an effective spin-1 model. However, for weak but finite coupling strength, we identify a symmetry broken phase differing from this effective spin-1 description. On the other hand, we underpin our argument with a numerical analysis making use of matrix product states.
Gravitino and scalar {tau}-lepton decays in supersymmetric models with broken R-parity
Energy Technology Data Exchange (ETDEWEB)
Hajer, Jan
2010-06-15
Mildly broken R-parity is known to provide a solution to the cosmological gravitino problem in supergravity extensions of the Standard Model. In this work we consider new effects occurring in the R-parity breaking Minimal Supersymmetric Standard Model including right-handed neutrino superfields. We calculate the most general vacuum expectation values of neutral scalar fields including left- and right-handed scalar neutrinos. Additionally, we derive the corresponding mass mixing matrices of the scalar sector. We recalculate the neutrino mass generation mechanisms due to right- handed neutrinos as well as by cause of R-parity breaking. Furthermore, we obtain a, so far, unknown formula for the neutrino masses for the case where both mechanisms are effective. We then constrain the couplings to bilinear R-parity violating couplings in order to accommodate R-parity breaking to experimental results. In order to constrain the family structure with a U(1){sub Q} flavor symmetry we furthermore embed the particle content into an SU(5) Grand Unified Theory. In this model we calculate the signal of decaying gravitino dark matter as well as the dominant decay channel of a likely NLSP, the scalar {tau}-lepton. Comparing the gravitino signal with results of the Fermi Large Area Telescope enables us to find a lower bound on the decay length of scalar {tau}-leptons in collider experiments. (orig.)
Gravitino and scalar τ-lepton decays in supersymmetric models with broken R-parity
International Nuclear Information System (INIS)
Hajer, Jan
2010-01-01
Mildly broken R-parity is known to provide a solution to the cosmological gravitino problem in supergravity extensions of the Standard Model. In this work we consider new effects occurring in the R-parity breaking Minimal Supersymmetric Standard Model including right-handed neutrino superfields. We calculate the most general vacuum expectation values of neutral scalar fields including left- and right-handed scalar neutrinos. Additionally, we derive the corresponding mass mixing matrices of the scalar sector. We recalculate the neutrino mass generation mechanisms due to right- handed neutrinos as well as by cause of R-parity breaking. Furthermore, we obtain a, so far, unknown formula for the neutrino masses for the case where both mechanisms are effective. We then constrain the couplings to bilinear R-parity violating couplings in order to accommodate R-parity breaking to experimental results. In order to constrain the family structure with a U(1) Q flavor symmetry we furthermore embed the particle content into an SU(5) Grand Unified Theory. In this model we calculate the signal of decaying gravitino dark matter as well as the dominant decay channel of a likely NLSP, the scalar τ-lepton. Comparing the gravitino signal with results of the Fermi Large Area Telescope enables us to find a lower bound on the decay length of scalar τ-leptons in collider experiments. (orig.)
International Nuclear Information System (INIS)
Polettini, Matteo; Esposito, Massimiliano
2014-01-01
In this paper and Paper II, we outline a general framework for the thermodynamic description of open chemical reaction networks, with special regard to metabolic networks regulating cellular physiology and biochemical functions. We first introduce closed networks “in a box”, whose thermodynamics is subjected to strict physical constraints: the mass-action law, elementarity of processes, and detailed balance. We further digress on the role of solvents and on the seemingly unacknowledged property of network independence of free energy landscapes. We then open the system by assuming that the concentrations of certain substrate species (the chemostats) are fixed, whether because promptly regulated by the environment via contact with reservoirs, or because nearly constant in a time window. As a result, the system is driven out of equilibrium. A rich algebraic and topological structure ensues in the network of internal species: Emergent irreversible cycles are associated with nonvanishing affinities, whose symmetries are dictated by the breakage of conservation laws. These central results are resumed in the relation a + b = s Y between the number of fundamental affinities a, that of broken conservation laws b and the number of chemostats s Y . We decompose the steady state entropy production rate in terms of fundamental fluxes and affinities in the spirit of Schnakenberg's theory of network thermodynamics, paving the way for the forthcoming treatment of the linear regime, of efficiency and tight coupling, of free energy transduction, and of thermodynamic constraints for network reconstruction
Polettini, Matteo; Esposito, Massimiliano
2014-07-14
In this paper and Paper II, we outline a general framework for the thermodynamic description of open chemical reaction networks, with special regard to metabolic networks regulating cellular physiology and biochemical functions. We first introduce closed networks "in a box", whose thermodynamics is subjected to strict physical constraints: the mass-action law, elementarity of processes, and detailed balance. We further digress on the role of solvents and on the seemingly unacknowledged property of network independence of free energy landscapes. We then open the system by assuming that the concentrations of certain substrate species (the chemostats) are fixed, whether because promptly regulated by the environment via contact with reservoirs, or because nearly constant in a time window. As a result, the system is driven out of equilibrium. A rich algebraic and topological structure ensues in the network of internal species: Emergent irreversible cycles are associated with nonvanishing affinities, whose symmetries are dictated by the breakage of conservation laws. These central results are resumed in the relation a + b = s(Y) between the number of fundamental affinities a, that of broken conservation laws b and the number of chemostats s(Y). We decompose the steady state entropy production rate in terms of fundamental fluxes and affinities in the spirit of Schnakenberg's theory of network thermodynamics, paving the way for the forthcoming treatment of the linear regime, of efficiency and tight coupling, of free energy transduction, and of thermodynamic constraints for network reconstruction.
Polar Kerr effect studies of time reversal symmetry breaking states in heavy fermion superconductors
Energy Technology Data Exchange (ETDEWEB)
Schemm, E.R., E-mail: eschemm@alumni.stanford.edu [Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305 (United States); Levenson-Falk, E.M. [Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305 (United States); Department of Physics, Stanford University, Stanford, CA 94305 (United States); Kapitulnik, A. [Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305 (United States); Department of Physics, Stanford University, Stanford, CA 94305 (United States); Department of Applied Physics, Stanford University, Stanford, CA 94305 (United States); Stanford Institute of Energy and Materials Science, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)
2017-04-15
Highlights: • Polar Kerr effect (PKE) probes broken time-reversal symmetry (TRS) in superconductors. • Absence of PKE below Tc in CeCoIn{sub 5} is consistent with dx2-y2 order parameter symmetry. • PKE in the B phase of the multiphase superconductor UPt3 agrees with an E2u model. • Data on URu2Si2 show broken TRS and additional structure in the superconducting state. - Abstract: The connection between chiral superconductivity and topological order has emerged as an active direction in research as more instances of both have been identified in condensed matter systems. With the notable exception of {sup 3}He-B, all of the known or suspected chiral – that is to say time-reversal symmetry-breaking (TRSB) – superfluids arise in heavy fermion superconductors, although the vast majority of heavy fermion superconductors preserve time-reversal symmetry. Here we review recent experimental efforts to identify TRSB states in heavy fermion systems via measurement of polar Kerr effect, which is a direct consequence of TRSB.
Fifty years of symmetry operations
International Nuclear Information System (INIS)
Wigner, E.P.
1978-01-01
The author begins by discussing the application of symmetry principles in classical physics, which began 150 years ago. He then offers a few remarks on the essence of these principles and their role in the structure of physics; events, laws of nature, and invariance principles - kinematic and then dynamic - are treated. After this general discussion of the various types of symmetries, he considers the fundamental differences in their application in classical and quantum physics; the symmetry principles have greater effectiveness in quantum theory. After a few critical remarks of a general nature on the invariance principles, the author reviews the application of symmetry principles in various areas of quantum mechanics: atomic spectra, molecular physics, solid state physics, nuclear physics, and particle physics. He notes that the role of the different symmetries recognized to be approximate provide the most interesting conclusions
Symmetry inheritance of scalar fields
International Nuclear Information System (INIS)
Ivica Smolić
2015-01-01
Matter fields do not necessarily have to share the symmetries with the spacetime they live in. When this happens, we speak of the symmetry inheritance of fields. In this paper we classify the obstructions of symmetry inheritance by the scalar fields, both real and complex, and look more closely at the special cases of stationary and axially symmetric spacetimes. Since the symmetry noninheritance is present in the scalar fields of boson stars and may enable the existence of the black hole scalar hair, our results narrow the possible classes of such solutions. Finally, we define and analyse the symmetry noninheritance contributions to the Komar mass and angular momentum of the black hole scalar hair. (paper)
Shape analysis with subspace symmetries
Berner, Alexander
2011-04-01
We address the problem of partial symmetry detection, i.e., the identification of building blocks a complex shape is composed of. Previous techniques identify parts that relate to each other by simple rigid mappings, similarity transforms, or, more recently, intrinsic isometries. Our approach generalizes the notion of partial symmetries to more general deformations. We introduce subspace symmetries whereby we characterize similarity by requiring the set of symmetric parts to form a low dimensional shape space. We present an algorithm to discover subspace symmetries based on detecting linearly correlated correspondences among graphs of invariant features. We evaluate our technique on various data sets. We show that for models with pronounced surface features, subspace symmetries can be found fully automatically. For complicated cases, a small amount of user input is used to resolve ambiguities. Our technique computes dense correspondences that can subsequently be used in various applications, such as model repair and denoising. © 2010 The Author(s).