Constrained gauge fields from spontaneous Lorentz violation
DEFF Research Database (Denmark)
Chkareuli, J. L.; Froggatt, C. D.; Jejelava, J. G.
2008-01-01
Spontaneous Lorentz violation realized through a nonlinear vector field constraint of the type AµAµ=M2 (M is the proposed scale for Lorentz violation) is shown to generate massless vector Goldstone bosons, gauging the starting global internal symmetries in arbitrary relativistically invariant...... theories. The gauge invariance appears in essence as a necessary condition for these bosons not to be superfluously restricted in degrees of freedom, apart from the constraint due to which the true vacuum in a theory is chosen by the Lorentz violation. In the Abelian symmetry case the only possible theory...... couplings when expressed in terms of the pure Goldstone vector modes. However, they do not lead to physical Lorentz violation due to the simultaneously generated gauge invariance. Udgivelsesdato: June 11...
Constrained Gauge Fields from Spontaneous Lorentz Violation
Chkareuli, J L; Jejelava, J G; Nielsen, H B
2008-01-01
Spontaneous Lorentz violation realized through a nonlinear vector field constraint of the type $A_{\\mu}^{2}=M^{2}$ ($M$ is the proposed scale for Lorentz violation) is shown to generate massless vector Goldstone bosons, gauging the starting global internal symmetries in arbitrary relativistically invariant theories. The gauge invariance appears in essence as a necessary condition for these bosons not to be superfluously restricted in degrees of freedom, apart from the constraint due to which the true vacuum in a theory is chosen by the Lorentz violation. In the Abelian symmetry case the only possible theory proves to be QED with a massless vector Goldstone boson naturally associated with the photon, while the non-Abelian symmetry case results in a conventional Yang-Mills theory. These theories, both Abelian and non-Abelian, look essentially nonlinear and contain particular Lorentz (and $CPT$) violating couplings when expressed in terms of the pure Goldstone vector modes. However, they do not lead to physical ...
International Nuclear Information System (INIS)
Mills, R.
1989-01-01
This article is a survey of the history and ideas of gauge theory. Described here are the gradual emergence of symmetry as a driving force in the shaping of physical theory; the elevation of Noether's theorem, relating symmetries to conservation laws, to a fundamental principle of nature; and the force of the idea (''the gauge principle'') that the symmetries of nature, like the interactions themselves, should be local in character. The fundamental role of gauge fields in mediating the interactions of physics springs from Noether's theorem and the gauge principle in a remarkably clean and elegant way, leaving, however, some tantalizing loose ends that might prove to be the clue to a future deeper level of understanding. The example of the electromagnetic field as the prototype gauge theory is discussed in some detail and serves as the basis for examining the similarities and differences that emerge in generalizing to non-Abelian gauge theories. The article concludes with a brief examination of the dream of total unification: all the forces of nature in a single unified gauge theory, with the differences among the forces due to the specific way in which the fundamental symmetries are broken in the local environment
International Nuclear Information System (INIS)
Itzykson, C.
1978-01-01
In these notes the author provides some background on the theory of gauge fields, a subject of increasing popularity among particle physicists (and others). Detailed motivations and applications which are covered in the other lectures of this school are not presented. In particular the application to weak interactions is omitted by referring to the introduction given by J. Ilipoulos a year ago (CERN Report 76-11). The aim is rather to stress those aspects which suggest that gauge fields may play some role in a future theory of strong interactions. (Auth.)
Covariant gauges for constrained systems
International Nuclear Information System (INIS)
Gogilidze, S.A.; Khvedelidze, A.M.; Pervushin, V.N.
1995-01-01
The method of constructing of extended phase space for singular theories which permits the consideration of covariant gauges without the introducing of a ghost fields, is proposed. The extension of the phase space is carried out by the identification of the initial theory with an equivalent theory with higher derivatives and applying to it the Ostrogradsky method of Hamiltonian description. 7 refs
Continuum gauge fields from lattice gauge fields
International Nuclear Information System (INIS)
Goeckeler, M.; Kronfeld, A.S.; Schierholz, G.; Wiese, U.J.
1993-01-01
On the lattice some of the salient features of pure gauge theories and of gauge theories with fermions in complex representations of the gauge group seem to be lost. These features can be recovered by considering part of the theory in the continuum. The prerequisite for that is the construction of continuum gauge fields from lattice gauge fields. Such a construction, which is gauge covariant and complies with geometrical constructions of the topological charge on the lattice, is given in this paper. The procedure is explicitly carried out in the U(1) theory in two dimensions, where it leads to simple results. (orig.)
International Nuclear Information System (INIS)
Bollini, C.G.; Giambiagi, J.J.; Tiomno, J.
1979-01-01
The construction of field strength copies without any gauge constraint is discussed. Several examples are given, one of which is not only a field strength copy but also (at the same time) a 'current copy'. (author) [pt
International Nuclear Information System (INIS)
Becchi, C.; Rouet, A.; Stora, R.
1975-10-01
Stora's analysis is continued in discussing the nonabelian (Yang-Mills) gauge field models (G.F.M.). The gauge independence of the physical scattering operator is discussed in some details and the connection between its unitary and the Slavnov symmetry outlined. Only the models involving semisimple gauge groups are considered. This greatly simplifies the analysis of the possible quantum corrections to the Quantum Action Principle which is reduced to the study of the cohomology group of the Lie algebra characterizing the gauge theory. The discussion is at the classical level for the algebraic properties of the SU(2) Higgs-Kibble-Englert-Brout-Faddeev-Popov lagrangian and its invariance under Slavnov identity transformations is exhibited. The renormalization of the Slavnov identity in the G.M.F. involving semisimple gauge groups is studied. The unitary and gauge independence of the physical S operator in the SU(2) H.K. model is dealt with [fr
International Nuclear Information System (INIS)
Leite Lopes, J.
1981-01-01
The book is intended to explain, in an elementary way, the basic notions and principles of gauge theories. Attention is centred on the Salem-Weinberg model of electro-weak interactions, as well as neutrino-lepton scattering and the parton model. Classical field theory, electromagnetic, Yang-Mills and gravitational gauge fields, weak interactions, Higgs mechanism and the SU(5) model of grand unification are also discussed. (U.K.)
Abelian gauge theories with tensor gauge fields
International Nuclear Information System (INIS)
Kapuscik, E.
1984-01-01
Gauge fields of arbitrary tensor type are introduced. In curved space-time the gravitational field serves as a bridge joining different gauge fields. The theory of second order tensor gauge field is developed on the basis of close analogy to Maxwell electrodynamics. The notion of tensor current is introduced and an experimental test of its detection is proposed. The main result consists in a coupled set of field equations representing a generalization of Maxwell theory in which the Einstein equivalence principle is not satisfied. (author)
Supersymmetric gauge field theories
International Nuclear Information System (INIS)
Slavnov, A.A.
1976-01-01
The paper is dealing with the role of supersymmetric gauge theories in the quantum field theory. Methods of manipulating the theories as well as possibilities of their application in elementary particle physics are presented. In particular, the necessity is explained of a theory in which there is symmetry between Fermi and Bose fields, in other words, of the supersymmetric gauge theory for construction of a scheme for the Higgs particle connecting parameters of scalar mesons with those of the rest fields. The mechanism of supersymmetry breaking is discussed which makes it possible to remain the symmetric procedure of renormalization intact. The above mechanism of spontaneous symmetry breaking is applied to demonstrate possibilities of constructing models of weak and electromagnetic interactions which would be acceptable from the point of view of experiments. It is noted that the supersymmetric gauge theories represent a natural technique for description of vector-like models
International Nuclear Information System (INIS)
Arodz, H.
1987-01-01
The two formulations of quantum theory of the free electromagnetic field are presented. In the Coulomb gauge approach the independent dynamical variables have been identified and then, in order to quantize the theory, it has been sufficient to apply the straightforward canonical quantization. In the Gupta-Bleuler approach the auxilliary theory is first considered. The straightforward canonical quantization of it leads to the quantum theory defined in the space G with indefinite norm. 15 refs. (author)
International Nuclear Information System (INIS)
Aref'eva, I.Ya.; Slavnov, A.A.
1981-01-01
This lecture is devoted to the discussion of gauge field theory permitting from the single point of view to describe all the interactions of elementary particles. The authors used electrodynamics and the Einstein theory of gravity to search for a renormgroup fixing a form of Lagrangian. It is shown that the gauge invariance added with the requirement of the minimum number of arbitraries in Lagrangian fixes unambigously the form of the electromagnetic interaction. The generalization of this construction for more complicate charge spaces results in the Yang-Mills theory. The interaction form in this theory is fixed with the relativity principle in the charge space. A quantum scheme of the Yang-Mills fields through the explicit separation of true dynamic variables is suggested. A comfortable relativistically invariant diagram technique for the calculation of a producing potential for the Green functions is described. The Ward generalized identities have been obtained and a procedure of the elimination of ultraviolet and infrared divergencies has been accomplished. Within the framework of QCD (quantum-chromodynamic) the phenomenon of the asymptotic freedom being the most successful prediction of the gauge theory of strong interactions was described. Working methods with QCD outside the framework of the perturbation theory have been described from a coupling constant. QCD is represented as a single theory possessing both the asymptotical freedom and the freedom retaining quarks [ru
International Nuclear Information System (INIS)
Pokorski, S.
1987-01-01
Quantum field theory forms the present theoretical framework for the understanding of the fundamental interactions of particle physics. This book examines gauge theories and their symmetries with an emphasis on their physical and technical aspects. The author discusses field-theoretical techniques and encourages the reader to perform many of the calculations presented. This book includes a brief introduction to perturbation theory, the renormalization programme, and the use of the renormalization group equation. Several topics of current research interest are covered, including chiral symmetry and its breaking, anomalies, and low energy effective lagrangians and some basics of supersymmetry
Maleknejad, A.; Sheikh-Jabbari, M. M.; Soda, J.
2013-07-01
The isotropy and homogeneity of the cosmic microwave background (CMB) favors “scalar driven” early Universe inflationary models. However, gauge fields and other non-scalar fields are far more common at all energy scales, in particular at high energies seemingly relevant to inflation models. Hence, in this review we consider the role and consequences, theoretical and observational, that gauge fields can have during the inflationary era. Gauge fields may be turned on in the background during inflation, or may become relevant at the level of cosmic perturbations. There have been two main classes of models with gauge fields in the background, models which show violation of the cosmic no-hair theorem and those which lead to isotropic FLRW cosmology, respecting the cosmic no-hair theorem. Models in which gauge fields are only turned on at the cosmic perturbation level, may source primordial magnetic fields. We also review specific observational features of these models on the CMB and/or the primordial cosmic magnetic fields. Our discussions will be mainly focused on the inflation period, with only a brief discussion on the post inflationary (p)reheating era. Large field models: The initial value of the inflaton field is large, generically super-Planckian, and it rolls slowly down toward the potential minimum at smaller φ values. For instance, chaotic inflation is one of the representative models of this class. The typical potential of large-field models has a monomial form as V(φ)=V0φn. A simple analysis using the dynamical equations reveals that for number of e-folds Ne larger than 60, we require super-Planckian initial field values,5φ0>3M. For these models typically ɛ˜η˜Ne-1. Small field models: Inflaton field is initially small and slowly evolves toward the potential minimum at larger φ values. The small field models are characterized by the following potential V(φ)=V0(1-(), which corresponds to a Taylor expansion about the origin, but more realistic
Towards weakly constrained double field theory
Directory of Open Access Journals (Sweden)
Kanghoon Lee
2016-08-01
Full Text Available We show that it is possible to construct a well-defined effective field theory incorporating string winding modes without using strong constraint in double field theory. We show that X-ray (Radon transform on a torus is well-suited for describing weakly constrained double fields, and any weakly constrained fields are represented as a sum of strongly constrained fields. Using inverse X-ray transform we define a novel binary operation which is compatible with the level matching constraint. Based on this formalism, we construct a consistent gauge transform and gauge invariant action without using strong constraint. We then discuss the relation of our result to the closed string field theory. Our construction suggests that there exists an effective field theory description for massless sector of closed string field theory on a torus in an associative truncation.
Lagrangian formalism for constrained systems. 2. Gauge symmetries
International Nuclear Information System (INIS)
Pyatov, P.N.
1990-01-01
Using the Lagrangian formalism for constrained systems all gauge symmetries peculiar for a given Lagrangian system and in establishing the relation between them and the constraints are constructed. Besides, the question about the possible dependence of gauge transformations on accelerations and other higher order time derivatives of coordinates is clarified. 14 refs
Introduction to gauge field theory
International Nuclear Information System (INIS)
Bailin, David; Love, Alexander
1986-01-01
The book is intended as an introduction to gauge field theory for the postgraduate student of theoretical particle physics. The topics discussed in the book include: path integrals, classical and quantum field theory, scattering amplitudes, feynman rules, renormalisation, gauge field theories, spontaneous symmetry breaking, grand unified theory, and field theories at finite temperature. (UK)
International Nuclear Information System (INIS)
Tellis, D.R.
2000-01-01
Full text: Instantons in pure Yang-Mills gauge theory have been studied extensively by physicists and mathematicians alike. The surprisingly rich topological structure plays an important role in hadron structure. A crucial role is played by how the boundary conditions on the gauge fields are imposed. While the topology of gauge fields in pure Yang-Mills gauge theory is understood for the compact manifold of the 4-sphere, the manifold of the 4-torus remains an active area of study. The latter is particularly important in the study of Lattice QCD
International Nuclear Information System (INIS)
Leite Lopes, J.
1998-04-01
In this work, we discuss the physical ideas which represents the basis for the unified gauge field model. Despite of the difficulties that we presently have for embodying in a natural manner muons and hadrons in that model, we have the feeling that we are on the way which seems to lead to the construction of a theory in which the Maxwell electromagnetic field and the Fermi weak interaction field are manifestations of a unique subjacent physical entity - the unified gauge fields. (author)
Gauge invariance of string fields
International Nuclear Information System (INIS)
Banks, T.; Peskin, M.E.
1985-10-01
Some work done to understand the appearance of gauge bosons and gravitons in string theories is reported. An action has been constructed for free (bosonic) string field theory which is invariant under an infinite set of gauge transformations which include Yang-Mills transformations and general coordinate transformations as special cases. 15 refs., 1 tab
'Baldin autumn' and gauge fields
International Nuclear Information System (INIS)
Konopleva, N.P.
2008-01-01
The paper is the reminiscences of the participant of the gauge field theory beginning and the first 'Baldin Autumn' conference in 1969. This conference was named 'Vector Mesons and Electromagnetic Interactions'. At that time, just the processes with vector mesons participation contained some experimental indications of new universal interactions existence. Vector dominance was the experimental evidence of physical reasons of the gauge field theory. In the course of time the gauge field theory form, which was under discussion thirty seven years ago, became generally recognized and experimentally corroborated. It led to construction of the well-known Standard Model of elementary particle interactions
New gauge symmetries in Witten's Ramond string field theory
International Nuclear Information System (INIS)
Kugo, Taichiro; Terao, Haruhiko
1988-01-01
Witten's Raymond string field theory is observed to possess new gauge symmetries, which guarantee the consistency and the equivalence of Witten's theory to the other formulation based on the constrained string field. The projection operator into the gauge-invariant sector is explicitly constructed using an operator similar to the picture changing operator. (orig.)
Directory of Open Access Journals (Sweden)
A. G. Sergeev
1986-01-01
Full Text Available We describe briefly the basic ideas and results of the twistor theory. The main points: twistor representation of Minkowsky space, Penrose correspondence and its geometrical properties, twistor interpretation of linear massless fields, Yang-Mills fields (including instantons and monopoles and Einstein-Hilbert equations.
Renormalization of gauge fields models
International Nuclear Information System (INIS)
Becchi, C.; Rouet, A.; Stora, R.
1974-01-01
A new approach to gauge field models is described. It is based on the Bogoliubov-Parasiuk-Hepp-Zimmermann (BPHZ) renormalization scheme making extensive use of the quantum action principle, and the Slavnov invariance. The quantum action principle being first summarized in the framework of the BPHZ is then applied to a global symmetry problem. The symmetry property of the gauge field Lagrangians in the tree approximation is exhibited, and the preservation of this property at the quantum level is discussed. The main results relative to the Abelian and SU(2) Higgs-Kibble models are briefly reviewed [fr
Introduction to gauge field theory
International Nuclear Information System (INIS)
Bailin, D.; Love, A.
1986-01-01
This book provides a postgraduate level introduction to gauge field theory entirely from a path integral standpoint without any reliance on the more traditional method of canonical quantisation. The ideas are developed by quantising the self-interacting scalar field theory, and are then used to deal with all the gauge field theories relevant to particle physics, quantum electrodynamics, quantum chromodynamics, electroweak theory, grand unified theories, and field theories at non-zero temperature. The use of these theories to make precise experimental predictions requires the development of the renormalised theories. This book provides a knowledge of relativistic quantum mechanics, but not of quantum field theory. The topics covered form a foundation for a knowledge of modern relativistic quantum field theory, providing a comprehensive coverage with emphasis on the details of actual calculations rather than the phenomenology of the applications
Gauge invariant fractional electromagnetic fields
International Nuclear Information System (INIS)
Lazo, Matheus Jatkoske
2011-01-01
Fractional derivatives and integrations of non-integers orders was introduced more than three centuries ago but only recently gained more attention due to its application on nonlocal phenomenas. In this context, several formulations of fractional electromagnetic fields was proposed, but all these theories suffer from the absence of an effective fractional vector calculus, and in general are non-causal or spatially asymmetric. In order to deal with these difficulties, we propose a spatially symmetric and causal gauge invariant fractional electromagnetic field from a Lagrangian formulation. From our fractional Maxwell's fields arose a definition for the fractional gradient, divergent and curl operators. -- Highlights: → We propose a fractional Lagrangian formulation for fractional Maxwell's fields. → We obtain gauge invariant fractional electromagnetic fields. → Our generalized fractional Maxwell's field is spatially symmetrical. → We discuss the non-causality of the theory.
Gauge invariant fractional electromagnetic fields
Energy Technology Data Exchange (ETDEWEB)
Lazo, Matheus Jatkoske, E-mail: matheuslazo@furg.br [Instituto de Matematica, Estatistica e Fisica - FURG, Rio Grande, RS (Brazil)
2011-09-26
Fractional derivatives and integrations of non-integers orders was introduced more than three centuries ago but only recently gained more attention due to its application on nonlocal phenomenas. In this context, several formulations of fractional electromagnetic fields was proposed, but all these theories suffer from the absence of an effective fractional vector calculus, and in general are non-causal or spatially asymmetric. In order to deal with these difficulties, we propose a spatially symmetric and causal gauge invariant fractional electromagnetic field from a Lagrangian formulation. From our fractional Maxwell's fields arose a definition for the fractional gradient, divergent and curl operators. -- Highlights: → We propose a fractional Lagrangian formulation for fractional Maxwell's fields. → We obtain gauge invariant fractional electromagnetic fields. → Our generalized fractional Maxwell's field is spatially symmetrical. → We discuss the non-causality of the theory.
International Nuclear Information System (INIS)
Torres del Castillo, G.F.; Departamento de Fisica, Centro de Investigacion y de Estudios Avanzados del IPN, Apartado Postal 14-740, 07000 Mexico, D. F., Mexico)
1987-01-01
It is shown that in an algebraically special space-time that admits a congruence of null strings, the Yang--Mills equations with sources reduce to a pair of nonlinear first-order differential equations for two matrices, provided that the gauge field is aligned with the congruence. In the case where the current is tangent to the null strings, the gauge field is determined by a matrix potential that has to satisfy a second-order differential equation with quadratic nonlinearities. As an example of this case, the Yang--Mills--Weyl equations are reduced, assuming that the multiplet of Weyl neutrino fields are also aligned with the congruence, and a reduced form of the Einstein--Yang--Mills--Weyl equations is also given
Gerbier, Fabrice; Goldman, Nathan; Lewenstein, Maciej; Sengstock, Klaus
2013-07-01
Building a universal quantum computer is a central goal of emerging quantum technologies, which has the potential to revolutionize science and technology. Unfortunately, this future does not seem to be very close at hand. However, quantum computers built for a special purpose, i.e. quantum simulators , are currently developed in many leading laboratories. Many schemes for quantum simulation have been proposed and realized using, e.g., ultracold atoms in optical lattices, ultracold trapped ions, atoms in arrays of cavities, atoms/ions in arrays of traps, quantum dots, photonic networks, or superconducting circuits. The progress in experimental implementations is more than spectacular. Particularly interesting are those systems that simulate quantum matter evolving in the presence of gauge fields. In the quantum simulation framework, the generated (synthetic) gauge fields may be Abelian, in which case they are the direct analogues of the vector potentials commonly associated with magnetic fields. In condensed matter physics, strong magnetic fields lead to a plethora of fascinating phenomena, among which the most paradigmatic is perhaps the quantum Hall effect. The standard Hall effect consists in the appearance of a transverse current, when a longitudinal voltage difference is applied to a conducting sample. For quasi-two-dimensional semiconductors at low temperatures placed in very strong magnetic fields, the transverse conductivity, the ratio between the transverse current and the applied voltage, exhibits perfect and robust quantization, independent for instance of the material or of its geometry. Such an integer quantum Hall effect, is now understood as a deep consequence of underlying topological order. Although such a system is an insulator in the bulk, it supports topologically robust edge excitations which carry the Hall current. The robustness of these chiral excitations against backscattering explains the universality of the quantum Hall effect. Another
Gauge invariant fractional electromagnetic fields
Lazo, Matheus Jatkoske
2011-09-01
Fractional derivatives and integrations of non-integers orders was introduced more than three centuries ago but only recently gained more attention due to its application on nonlocal phenomenas. In this context, several formulations of fractional electromagnetic fields was proposed, but all these theories suffer from the absence of an effective fractional vector calculus, and in general are non-causal or spatially asymmetric. In order to deal with these difficulties, we propose a spatially symmetric and causal gauge invariant fractional electromagnetic field from a Lagrangian formulation. From our fractional Maxwell's fields arose a definition for the fractional gradient, divergent and curl operators.
Systematics of higher-spin gauge fields
International Nuclear Information System (INIS)
de Wit, B.; Freedman, D.Z.
1980-01-01
Free-field theories for symmetric tensor and tensor-spinor gauge fields have recently been obtained which describe massless particles of arbitrary integer or half-integer spin. An independent discussion of these field theories is given here, based on a hierarchy of generalized Christoffel symbols with simple gauge transformation properties. The necessity of certain constraints on gauge fields and parameters is easily seen. Wave equations and Lagrangians are expressed in terms of the Christoffel symbols, and the independent modes of the system are counted in covariant gauges. Minimal-coupling inconsistency and a combined system of higher-spin boson gauge fields interacting with relativistic particles is discussed
Magnetoelasticity as a gauge field
International Nuclear Information System (INIS)
Zorawski, Marek
1987-01-01
The goal of the paper is to formulate such a system in such a metric space that the geodesics of the space give the movement equations with the influence of electromagnetic forces. Local fields (stress) should be, of course, also included in the movement equations. For the geometrical structure of energy-momentum tensor, the known Einstein equation is adopted. It is also supposed that the Bianchi identities hold. Then in Riemannian space a non-holonomic system of reference is introduced, and the anholonomity object is associated to the electromagnetic field, as a gauge field. The considered theory is the classical one, it is not difficult to extend it to quantum field theory. (Auth.)
Gauge fields in a torsion field
International Nuclear Information System (INIS)
Rosu, Ion
2004-01-01
In this paper we analyse the motion and the field equations in a non-null curvature and torsion space. In this 4-n dimensional space, the connection coefficients are γ bc a = 1/2S bc a + 1/2T bc a, where S bc a is the symmetrical part and T bc a are the components of the torsion tensor. We will consider that all the fields depend on x = x α , α = 1,2,3,4 and do not depend on y = y k , k=1,2,...,n. The factor S bc a depends on the components of the metric tensor g αβ (x) and on the gauge fields A ν s 0 (x) and the components of the torsion depend only on the gauge fields A ν s 0 (x). We take into consideration the particular case for which the geodesic equations coincide with the motion equations in the presence of the gravitational and the gauge fields. In this case the field equations are Einstein equations in a 4-n dimensional space. We show that both the geodesic equations and the field equations can be obtained from a variational principle. (author)
Tensor gauge condition and tensor field decomposition
Zhu, Ben-Chao; Chen, Xiang-Song
2015-10-01
We discuss various proposals of separating a tensor field into pure-gauge and gauge-invariant components. Such tensor field decomposition is intimately related to the effort of identifying the real gravitational degrees of freedom out of the metric tensor in Einstein’s general relativity. We show that as for a vector field, the tensor field decomposition has exact correspondence to and can be derived from the gauge-fixing approach. The complication for the tensor field, however, is that there are infinitely many complete gauge conditions in contrast to the uniqueness of Coulomb gauge for a vector field. The cause of such complication, as we reveal, is the emergence of a peculiar gauge-invariant pure-gauge construction for any gauge field of spin ≥ 2. We make an extensive exploration of the complete tensor gauge conditions and their corresponding tensor field decompositions, regarding mathematical structures, equations of motion for the fields and nonlinear properties. Apparently, no single choice is superior in all aspects, due to an awkward fact that no gauge-fixing can reduce a tensor field to be purely dynamical (i.e. transverse and traceless), as can the Coulomb gauge in a vector case.
Contemporary status of gauge fields
International Nuclear Information System (INIS)
Slavnov, A.A.
1979-01-01
A successive and a self-consistent scheme of calculation is developed for the Yang-Mills theory. Boundary conditions related to the problem on the physical vacuum are predetermined for solving the field theory equations. It is noted that the principal problem for the Yang-Mills theory consists in finding the actual ground state. The role of instantons in constructing the gauge field ground state and of the dynamic mechanism of quark confinement are also discussed. An assumption has been made that the Yang-Mills theory can be solved exactly. This assumption is based on analogy between the Yang-Mills theory and the two-dimensional nonlinear σ-model. An exceptionality of the Yang-Mills theory is stressed which consists in the fact that it is a unique massless vector field theory in which no patologies are observed connected with nonpositive determination of energy
Meta fluid dynamic as a gauge field theory
International Nuclear Information System (INIS)
Mendes, A.C.R.; Neves, C.; Oliveira, W.; Takakura, F.I.
2003-01-01
In this paper, the analog of Maxwell electromagnetism for hydrodynamic turbulence, the meta fluid dynamics, is extended in order to reformulate the meta fluid dynamics as a gauge field theory. That analogy opens up the possibility to investigate this theory as a constrained system. Having this possibility in mind, we propose a Lagrangian to describe this new theory of turbulence and, subsequently, analyze it from the symplectic point of view. From this analysis, a hidden gauge symmetry is revealed, providing a clear interpretation and meaning of the physics behind the meta fluid theory. Also, the geometrical interpretation to the gauge symmetries is discussed. (author)
Adding gauge fields to Kaplan's fermions
International Nuclear Information System (INIS)
Blum, T.; Kaerkkaeinen, L.
1994-01-01
We experiment with adding dynamical gauge field to Kaplan (defect) fermions. In the case of U(1) gauge theory we use an inhomogeneous Higgs mechanism to restrict the 3d gauge dynamics to a planar 2d defect. In our simulations the 3d theory produce the correct 2d gauge dynamics. We measure fermion propagators with dynamical gauge fields. They posses the correct chiral structure. The fermions at the boundary of the support of the gauge field (waveguide) are non-chiral, and have a mass two times heavier than the chiral modes. Moreover, these modes cannot be excited by a source at the defect; implying that they are dynamically decoupled. We have also checked that the anomaly relation is fullfilled for the case of a smooth external gauge field. (orig.)
On behaviour of Weyl's gauge field
International Nuclear Information System (INIS)
Yuan Zhong Zhang.
1990-05-01
We consider a system, consisting of a metric tensor g μυ , a scalar field φ, a Weyl's gauge field A μ and a scalar matter field Φ, which is invariant under general coordinate transformation and Weyl's gauge transformation. Two kinds of identities and field equations are given and discussed. A special space-time with g μυ =φ -2 η μυ is considered in a gauge-independent manner. We point out that in a correct treatment where g μυ is not regarded as an independent variable, an auxiliary condition for Weyl's gauge field cannot be obtained. Therefore Weyl's gauge field can be treated as a usual field of positive norm. (author). 11 refs
Gauge field condensation in geometric quantum chromodynamics
International Nuclear Information System (INIS)
Guendelman, E.I.
1991-09-01
In odd number of dimensions, it is possible to construct general covariant gauge theories, where the metric is not an independent variable, but local function of the gauge fields. Starting from standardly defined gauge theory, upon functional integration of some variables, we could end up with such moodels. For models with SU(2) and SU(3) symmetry in three dimensions, gauge field condensation take place in the vacuum, which is nevertheless homogeneous and isotropic up to a gauge transformation, provided the space is flat. Introducing Higgs fields that spontaneously break the gauge symmetry, we get a breakdown of the homogenity and isotropy of the vacuum. Finally, we discuss how some of this ideas can be generalized to four and other even dimensions. (author)
Measurability of non-abelium gauge fields
Energy Technology Data Exchange (ETDEWEB)
Ivanenko, D.D.; Obukhov, Yu.N.
New estimations of the accuracy of measurement of non-abeliar gauge field components are obtained on the base of qualitative analysis of the test body equations of motion. They generalize the Bohr and Rosenfeld results on the measurability of an electomagnetic field for the case of an arbitrary gauge group.
A Third-Rank Tensor Field Based on a U(1) Gauge Theory in Loop Space
Shinichi, DEGUCHI; Tadahito, NAKAJIMA; Department of Physics and Atomic Energy Research Institute College of Science and Technology; Department of Physics and Atomic Energy Research Institute College of Science and Technology
1995-01-01
We derive the Stueckelberg formalism extended to a third-rank tensor field from a U(1) gauge theory in loop space, the space of all loops in space-time. The third-rank tensor field is regarded as a constrained U(1) gauge field on the loop space.
Anomalous coupling of scalars to gauge fields
Energy Technology Data Exchange (ETDEWEB)
Brax, Philippe [CEA, IPhT, CNRS, URA 2306, Gif-sur-Yvette (France). Inst. de Physique Theorique; Burrage, Clare [Geneve Univ. (Switzerland). Dept. de Physique Theorique; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Davis, Anne-Christine [Centre for Mathematical Sciences, Cambridge (United Kingdom). Dept. of Applied Mathematics and Theoretical Physics; Seery, David [Sussex Univ., Brighton (United Kingdom). Dept. of Physics and Astronomy; Weltman, Amanda [Cape Town Univ., Rondebosch (South Africa). Astronomy, Cosmology and Gravity Centre
2010-10-15
We study the transformation properties of a scalar-tensor theory, coupled to fermions, under the Weyl rescaling associated with a transition from the Jordan to the Einstein frame. We give a simple derivation of the corresponding modification to the gauge couplings. After changing frames, this gives rise to a direct coupling between the scalar and the gauge fields. (orig.)
Anomalous coupling of scalars to gauge fields
International Nuclear Information System (INIS)
Brax, Philippe; Davis, Anne-Christine; Seery, David; Weltman, Amanda
2010-10-01
We study the transformation properties of a scalar-tensor theory, coupled to fermions, under the Weyl rescaling associated with a transition from the Jordan to the Einstein frame. We give a simple derivation of the corresponding modification to the gauge couplings. After changing frames, this gives rise to a direct coupling between the scalar and the gauge fields. (orig.)
Constraints on Gauge Field Production during Inflation
DEFF Research Database (Denmark)
Nurmi, Sami; Sloth, Martin Snoager
2014-01-01
In order to gain new insights into the gauge field couplings in the early universe, we consider the constraints on gauge field production during inflation imposed by requiring that their effect on the CMB anisotropies are subdominant. In particular, we calculate systematically the bispectrum...... of the primordial curvature perturbation induced by the presence of vector gauge fields during inflation. Using a model independent parametrization in terms of magnetic non-linearity parameters, we calculate for the first time the contribution to the bispectrum from the cross correlation between the inflaton...
Elastic Gauge Fields in Weyl Semimetals
Cortijo, Alberto; Ferreiros, Yago; Landsteiner, Karl; Hernandez Vozmediano, Maria Angeles
We show that, as it happens in graphene, elastic deformations couple to the electronic degrees of freedom as pseudo gauge fields in Weyl semimetals. We derive the form of the elastic gauge fields in a tight-binding model hosting Weyl nodes and see that this vector electron-phonon coupling is chiral, providing an example of axial gauge fields in three dimensions. As an example of the new response functions that arise associated to these elastic gauge fields, we derive a non-zero phonon Hall viscosity for the neutral system at zero temperature. The axial nature of the fields provides a test of the chiral anomaly in high energy with three axial vector couplings. European Union structural funds and the Comunidad de Madrid MAD2D-CM Program (S2013/MIT-3007).
Gravitating SO (3,1) gauge field
International Nuclear Information System (INIS)
Aragone, C.; Restuccia, A.
1978-01-01
In this article, we postulate SO (3,1) as a local symmetry of any relativistic theory. This is equivalent to assuming the existence of a gauge field associated with this noncompact group. This SO (3,1) gauge field is the spinorial affinity which usually appears when we deal with weighting spinors, which, as is well known, cannot be coupled to the metric tensor field. Furthermore, according to the integral approach to gauge fields proposed by Yang, it is also recognized that in order to obtain models of gravity we have to introduce ordinary affinities as the gauge field associated with GL (4) (the local symmetry determined by the parallel transport). Thus if we assume both GL (4) and SO (3,1) as local independent symmetries we are led to analyze the dynamical gauge system constituted by the Einstein field interacting with the SO (3,1) Weyl--Yang gauge field. We think this system is a possible model of strong gravity. Once we give the first-order action for this Einstein--Weyl--Yang system we study whether the SO (3,1) gauge field could have a tetrad associated with it. It is also shown that both fields propagate along a unique characteristic cone. Algebraic and differential constraints are solved when the system evolves along a null coordinate. The unconstrained expression for the action of the system is found working in the Bondi gauge. That allows us to exhibit an explicit expression of the dynamical generator of the system. Its signature turns out to be nondefinite, due to the nondefinite contribution of the Weyl--Yang field, which has the typical spinorial behavior. A conjecture is made that such an unpleasant feature could be overcome in the quantized version of this model
Toward a gauge field theory of gravity.
Yilmaz, H.
Joint use of two differential identities (Bianchi and Freud) permits a gauge field theory of gravity in which the gravitational energy is localizable. The theory is compatible with quantum mechanics and is experimentally viable.
Derivation of the Finslerian gauge field equations
International Nuclear Information System (INIS)
Asanov, G.S.
1984-01-01
As is well known the simplest way of formulating the equations for the Yang-Mills gauge fields consists in taking the Lagrangian to be quadratic in the gauge tensor, whereas the application of such an approach to the gravitational field yields equations which are of essentially more complicated structure than the Einstein equations. On the other hand, in the gravitational field theory the Lagrangian can be constructed to be of forms which may be both quadratic and linear in the curvature tensor, whereas the latter possibility is absent in the current gauge field theories. In previous work it has been shown that the Finslerian structure of the space-time gives rise to certain gauge fields provided that the internal symmetries may be regarded as symmetries of a three-dimensional Riemannian space. Continuing this work we show that appropriate equations for these gauge fields can be formulated in both ways, namely on the basis of the quadratic Lagrangian or, if a relevant generalization of the Palatini method is applied, on the basis of a Lagrangian linear in the gauge field strength tensor. The latter possibility proves to result in equations which are similar to the Einstein equations, a distinction being that the Finslerian Cartan curvature tensor rather then the Riemann curvature tensor enters the equations. (author)
World-sheet gauge fields in superstrings
International Nuclear Information System (INIS)
Porrati, M.; Tomboulis, E.T.
1989-01-01
We investigate the introduction of world-sheet 2-dimensional gauge fields in a manner consistent with world-sheet supersymmetry. We obtain the effective string action resulting from the exact integration over the world-sheet gauge fields to show that it generally describes string models with spontaneous breaking of gauge symmetries with continuous breaking parameters. We examine the question of spacetime supersymmetry spontaneous breaking, and show that breaking with continuous, in particular arbitrarily small breaking parameters does not occur; only breaking for discrete values of parameters is possible. (orig.)
The extended local gauge invariance and the BRS symmetry in stochastic quantization of gauge fields
International Nuclear Information System (INIS)
Nakazawa, Naohito.
1989-05-01
We investigate the BRS invariance of the first-class constrained systems in the context of the stochastic quantization. For the first-class constrained systems, we construct the nilpotent BRS transformation and the BRS invariant stochastic effective action based on the D+1 dimensional field theoretical formulation of stochastic quantization. By eliminating the multiplier field of the gauge fixing condition and an auxiliary field, it is shown that there exists a truncated BRS transformation which satisfies the nilpotency condition. The truncated BRS invariant stochastic action is also derived. As the examples of the general formulation, we investigate the BRS invariant structure in the massless and massive Yang-Mills fields in stochastic quantization. (author)
Gauge bridges in classical field theory
International Nuclear Information System (INIS)
Jakobs, S.
2009-03-01
In this thesis Poisson structures of two classical gauge field theories (Maxwell-Klein-Gordon- and Maxwell-Dirac-system) are constructed using the parametrix construction of Green's functions. Parametrices for the Maxwell-Klein-Gordon- and Maxwell-Dirac-system are constructed in Minkowski space and this construction is later generalized to curved space times for the Maxwell-Klein-Gordon-system. With these Green's functions Poisson brackets will be defined as Peierls brackets. Finally non-local, gauge invariant observables, the so-called ''gauge bridges''are constructed. Gauge bridges are the matrix elements of holonomy operators. It is shown, that these emerge from Poisson brackets of local, gauge invariant observables. (orig.)
Group theory and lattice gauge fields
International Nuclear Information System (INIS)
Creutz, M.
1988-09-01
Lattice gauge theory, formulated in terms of invariant integrals over group elements on lattice bonds, benefits from many group theoretical notions. Gauge invariance provides an enormous symmetry and powerful constraints on expectation values. Strong coupling expansions require invariant integrals over polynomials in group elements, all of which can be evaluated by symmetry considerations. Numerical simulations involve random walks over the group. These walks automatically generate the invariant group measure, avoiding explicit parameterization. A recently proposed overrelaxation algorithm is particularly efficient at exploring the group manifold. These and other applications of group theory to lattice gauge fields are reviewed in this talk. 17 refs
Emergent Gauge Fields in Holographic Superconductors
Domènech, Oriol; Pomarol, Alex; Salvio, Alberto; Silva, Pedro J
2010-01-01
Holographic superconductors have been studied so far in the absence of dynamical electromagnetic fields, namely in the limit in which they coincide with holographic superfluids. It is possible, however, to introduce dynamical gauge fields if a Neumann-type boundary condition is imposed on the AdS-boundary. In 3+1 dimensions, the dual theory is a 2+1 dimensional CFT whose spectrum contains a massless gauge field, signaling the emergence of a gauge symmetry. We study the impact of a dynamical gauge field in vortex configurations where it is known to significantly affect the energetics and phase transitions. We calculate the critical magnetic fields H_c1 and H_c2, obtaining that holographic superconductors are of Type II (H_c1 < H_c2). We extend the study to 4+1 dimensions where the gauge field does not appear as an emergent phenomena, but can be introduced, by a proper renormalization, as an external dynamical field. We also compare our predictions with those arising from a Ginzburg-Landau theory and identif...
Gauge field vacuum structure in geometrical aspect
International Nuclear Information System (INIS)
Konopleva, N.P.
2003-01-01
Vacuum conception is one of the main conceptions of quantum field theory. Its meaning in classical field theory is also very profound. In this case the vacuum conception is closely connected with ideas of the space-time geometry. The global and local geometrical space-time conceptions lead to different vacuum definitions and therefore to different ways of physical theory construction. Some aspects of the gauge field vacuum structure are analyzed. It is shown that in the gauge field theory the vacuum Einstein equation solutions describe the relativistic vacuum as common vacuum of all gauge fields and its sources. Instantons (both usual and hyperbolical) are regarded as nongravitating matter, because they have zero energy-momentum tensors and correspond to vacuum Einstein equations
Gauge field theories an introduction with applications
Guidry, Mike
1991-01-01
Acquaints readers with the main concepts and literature of elementary particle physics and quantum field theory. In particular, the book is concerned with the elaboration of gauge field theories in nuclear physics; the possibility of creating fundamental new states of matter such as an extended quark-gluon plasma in ultra-relativistic heavy ion collisions; and the relation of gauge theories to the creation and evolution of the universe. Divided into three parts, it opens with an introduction to the general principles of relativistic quantum field theory followed by the essential ingredients of gauge fields for weak and electromagnetic interactions, quantum chromodynamics and strong interactions. The third part is concerned with the interface between modern elementary particle physics and "applied disciplines" such as nuclear physics, astrophysics and cosmology. Includes references and numerous exercises
Vacuum in intensive gauge fields
International Nuclear Information System (INIS)
Matinian, S.G.
1977-12-01
The behaviour of vacuum in a covariantly constant Yang-Mills field is considered. The expressions for the effective Lagrangian in an intensive field representing the asymptotic freedom of the theory are found
Extended pure Yang-Mills gauge theories with scalar and tensor gauge fields
International Nuclear Information System (INIS)
Gabrielli, E.
1991-01-01
The usual abelian gauge theory is extended to an interacting Yang-Mills-like theory containing vector, scalar and tensor gauge fields. These gauge fields are seen as components along the Clifford algebra basis of a gauge vector-spinorial field. Scalar fields φ naturally coupled to vector and tensor fields have been found, leading to a natural φ 4 coupling in the lagrangian. The full expression of the lagrangian for the euclidean version of the theory is given. (orig.)
Confinement through tensor gauge fields
International Nuclear Information System (INIS)
Salam, A.; Strathdee, J.
1977-12-01
Using the 0(3,2)-symmetric de Sitter solution of Einstein's equation describing a strongly interacting tensor field it is shown that hadronic bags confining quarks can be represented as de Sitter ''micro-universes'' with radii given 1/R 2 =lambdak 2 /6. Here k 2 and lambda are the strong coupling and the ''cosmological'' constant which apear in the Einstein equation used. Surprisingly the energy spectrum for the two-body hadronic states is the same as that for a harmonic oscillator potential, though the wave functions are completely different. The Einstein equation can be extended to include colour for the tensor fields
Finite N=1 SUSY gauge field theories
International Nuclear Information System (INIS)
Kazakov, D.I.
1986-01-01
The authors give a detailed description of the method to construct finite N=1 SUSY gauge field theories in the framework of N=1 superfields within dimensional regularization. The finiteness of all Green functions is based on supersymmetry and gauge invariance and is achieved by a proper choice of matter content of the theory and Yukawa couplings in the form Y i =f i (ε)g, where g is the gauge coupling, and the function f i (ε) is regular at ε=0 and is calculated in perturbation theory. Necessary and sufficient conditions for finiteness are determined already in the one-loop approximation. The correspondence with an earlier proposed approach to construct finite theories based on aigenvalue solutions of renormalization-group equations is established
Gauge field theories. Part three. Renormalization
International Nuclear Information System (INIS)
Frampon, P.H.
1978-01-01
The renormalization of nonabelian gauge theories both with exact symmetry and with spontaneous symmetry breaking is discussed. The method of dimensional regularization is described and used in the ensuing discussion. Triangle anomalies and their implications and the method for cancellation of anomalies in an SU(2) x U(1) theory, introduction of the BRS form of local gauge transformation and its use for the iterative proof of renormalizability to all orders for pure Yang--Mills and with fermion and scalar matter fields are considered. Lastly for massive vectors arising from spontaneous breaking, the demonstration of renormalizability is given, using the 't Hooft gauges introduced first in 1971. While the treatment is not totally rigorous, all the principle steps are given. 108 references
Gauge field copies and Higgs mechanism
International Nuclear Information System (INIS)
Gleiser, M.
1982-07-01
From the algebric classification of the possible solutions of the necessary and sufficient condition for the existence of gauge field copies in two possible classes the Higgs mechanism for the potential obtained from the difference between two copied potentials is applied. It is shown that for class I 'electric type' it is possible to construct a vector field that satisfies an electromagnetic wave equation. For class I 'magnetic type', a vector field that satisfies a non-linear equation as a consequence of the non-abelianity of the theory, is obtained. It is shown that for class II it's not possible to apply the Higgs mechanism. A possible physical interpretation for the 'gauge field copies' phenomenon, is obtained. (author) [pt
On gauge fixing and quantization of constrained Hamiltonian systems
International Nuclear Information System (INIS)
Dayi, O.F.
1989-06-01
In constrained Hamiltonian systems which possess first class constraints some subsidiary conditions should be imposed for detecting physical observables. This issue and quantization of the system are clarified. It is argued that the reduced phase space and Dirac method of quantization, generally, differ only in the definition of the Hilbert space one should use. For the dynamical systems possessing second class constraints the definition of physical Hilbert space in the BFV-BRST operator quantization method is different from the usual definition. (author). 18 refs
Shadow fields and local supersymmetric gauges
International Nuclear Information System (INIS)
Baulieu, L.; Bossard, G.; Sorella, S.P.
2006-01-01
To control supersymmetry and gauge invariance in super-Yang-Mills theories we introduce new fields, called shadow fields, which enable us to enlarge the conventional Faddeev-Popov framework and write down a set of useful Slavnov-Taylor identities. These identities allow us to address and answer the issue of the supersymmetric Yang-Mills anomalies, and to perform the conventional renormalization programme in a fully regularization-independent way
Numerical studies of gauge field theories
International Nuclear Information System (INIS)
Creutz, M.
1981-06-01
Monte Carlo simulation of statistical systems is a well established technique of the condensed matter physicist. In the last few years, particle theorists have rediscovered this method and are having a marvelous time applying it to quantized gauge field theories. The main result has been strong numerical evidence that the standard SU(3) non-Abelian gauge theory of the strong interaction is capable of simultaneously confining quarks into the physical hadrons and exhibiting asymptotic freedom, the phenomenon of quark interactions being small at short distances. In four dimensions, confinement is a non-perturbative phenomenon. Essentially all models of confinement tie widely separated quarks together with strings of gauge field flux. This gives rise to a linear potential at long distances. A Monte Carlo program generates a sequence of field configuration by a series of random changes of the fields. The algorithm is so constructed that ultimately the probability density for finding any given configuration is proportional to the Boltzmann weighting. We bring our lattices into thermal equilibrium with a heat bath at a temperature specified by the coupling constant. Thus we do computer experiments with four-dimensional crystals stored in a computer memory. As the entire field configuration is stored, we have access to any correlation function desired. These lectures describe the kinds of experiments being done and the implications of these results for strong interaction physics
Emergent Abelian Gauge Fields from Noncommutative Gravity
Directory of Open Access Journals (Sweden)
Allen Stern
2010-02-01
Full Text Available We construct exact solutions to noncommutative gravity following the formulation of Chamseddine and show that they are in general accompanied by Abelian gauge fields which are first order in the noncommutative scale. This provides a mechanism for generating cosmological electromagnetic fields in an expanding space-time background, and also leads to multipole-like fields surrounding black holes. Exact solutions to noncommutative Einstein-Maxwell theory can give rise to first order corrections to the metric tensor, as well as to the electromagnetic fields. This leads to first order shifts in the horizons of charged black holes.
Gauge field configurations in curved spacetimes (II)
International Nuclear Information System (INIS)
Boutaleb-Joutei, H.; Chakrabarti, A.; Comtet, A.
1979-05-01
One continues the study of gauge field configurations in curved spaces, using the formalism and results of a previous paper. A class of static, finite action, selfdual solutions of SU(2) gauge fields on a Euclidean section of de Sitter space is presented. The action depends on a continuous parameter. The spin connection solution is obtained as a particular case and a certain passage to the limiting case of a flat space is shown to reproduce the Euclidean Prasad-Sommerfield solution. The significance and possible interest of such solutions are discussed. The results are then generalized to a non-Einstein but conformally flat space, including de Sitter space as an Einstein limit. Next Baecklund type transformations are constructed starting from selfduality constraints for such curved spaces. These transformations are applied to the above mentioned solutions. The last two sections contain remarks on solutions with a background Robinson-Bertotti metric and on static, axially symmetric solutions respectively
Zero energy gauge fields and the phases of a gauge theory
International Nuclear Information System (INIS)
Guendelman, E.I.
1990-01-01
A new approach to the definition of the phases of a Poincare invariant gauge theory is developed. It is based on the role of gauge transformations that change the asymptotic value of the gauge fields from zero to a constant. In the context of theories without Higgs fields, this symmetry can be spontaneously broken when the gauge fields are massless particles, explicitly broken when the gauge fields develop a mass. Finally, the vacuum can be invariant under this transformation, this last case can be achieved when the theory has a violent infrared behavior, which in some theories can be connected to a confinement mechanism
Fundamental problems of gauge field theory
International Nuclear Information System (INIS)
Velo, G.; Wightman, A.S.
1986-01-01
As a result of the experimental and theoretical developments of the last two decades, gauge field theory, in one form or another, now provides the standard language for the description of Nature; QCD and the standard model of the electroweak interactions illustrate this point. It is a basic task of mathematical physics to provide a solid foundation for these developments by putting the theory in a physically transparent and mathematically rigorous form. The lecture notes collected in this volume concentrate on the many unsolved problems which arise here, and on the general ideas and methods which have been proposed for their solution. In particular, the use of rigorous renormalization group methods to obtain control over the continuum limit of lattice gauge field theories, the exploration of the extraordinary enigmatic connections between Kac-Moody-Virasoro algebras and string theory, and the systematic use of the theory of local algebras and indefinite metric spaces to classify the charged C* states in gauge field theories are mentioned
Linear b-gauges for open string fields
International Nuclear Information System (INIS)
Kiermaier, Michael; Zwiebach, Barton; Sen, Ashoke
2008-01-01
Motivated by Schnabl's gauge choice, we explore open string perturbation theory in gauges where a linear combination of antighost oscillators annihilates the string field. We find that in these linear b-gauges different gauge conditions are needed at different ghost numbers. We derive the full propagator and prove the formal properties which guarantee that the Feynman diagrams reproduce the correct on-shell amplitudes. We find that these properties can fail due to the need to regularize the propagator, and identify a large class of linear b-gauges for which they hold rigorously. In these gauges the propagator has a non-anomalous Schwinger representation and builds Riemann surfaces by adding strip-like domains. Projector-based gauges, like Schnabl's, are not in this class of gauges but we construct a family of regular linear b-gauges which interpolate between Siegel gauge and Schnabl gauge
Gauge-invariant intense-field approximations to all orders
International Nuclear Information System (INIS)
Faisal, F H M
2007-01-01
We present a gauge-invariant formulation of the so-called strong-field KFR approximations in the 'velocity' and 'length' gauges and demonstrate their equivalence in all orders. The theory thus overcomes a longstanding discrepancy between the strong-field velocity and the length-gauge approximations for non-perturbative processes in intense laser fields. (fast track communication)
A gauge field theory of fermionic continuous-spin particles
Energy Technology Data Exchange (ETDEWEB)
Bekaert, X., E-mail: xavier.bekaert@lmpt.univ-tours.fr [Laboratoire de Mathématiques et Physique Théorique, Unité Mixte de Recherche 7350 du CNRS, Fédération de Recherche 2964 Denis Poisson, Université François Rabelais, Parc de Grandmont, 37200 Tours (France); B.W. Lee Center for Fields, Gravity and Strings, Institute for Basic Science, Daejeon (Korea, Republic of); Najafizadeh, M., E-mail: mnajafizadeh@gmail.com [Laboratoire de Mathématiques et Physique Théorique, Unité Mixte de Recherche 7350 du CNRS, Fédération de Recherche 2964 Denis Poisson, Université François Rabelais, Parc de Grandmont, 37200 Tours (France); Department of Physics, Faculty of Sciences, University of Kurdistan, 66177-15177 Sanandaj (Iran, Islamic Republic of); Setare, M.R., E-mail: rezakord@ipm.ir [Department of Physics, Faculty of Sciences, University of Kurdistan, 66177-15177 Sanandaj (Iran, Islamic Republic of)
2016-09-10
In this letter, we suggest a local covariant action for a gauge field theory of fermionic Continuous-Spin Particles (CSPs). The action is invariant under gauge transformations without any constraint on both the gauge field and the gauge transformation parameter. The Fang–Fronsdal equations for a tower of massless fields with all half-integer spins arise as a particular limit of the equation of motion of fermionic CSPs.
A gauge field theory of fermionic continuous-spin particles
International Nuclear Information System (INIS)
Bekaert, X.; Najafizadeh, M.; Setare, M.R.
2016-01-01
In this letter, we suggest a local covariant action for a gauge field theory of fermionic Continuous-Spin Particles (CSPs). The action is invariant under gauge transformations without any constraint on both the gauge field and the gauge transformation parameter. The Fang–Fronsdal equations for a tower of massless fields with all half-integer spins arise as a particular limit of the equation of motion of fermionic CSPs.
Gauge field theories. 3. enl. ed.
International Nuclear Information System (INIS)
Frampton, Paul H.
2008-01-01
Gauge theories provide a unified framework to describe three of the four universal forces known so far: the quantum field theories of electromagnetism, the weak force and the strong force. They are an essential part of the so-called standard model of particles and matter. The first edition of this work was quickly adopted by universities and other institutions of higher learning around the world. Completely updated, this third edition continues to be an ideal reference on the subject. In total, more than a quarter of the content has been changed or added. The tried-and-tested logical structuring of the material on gauge invariance, quantization, and renormalization has been retained, while the chapters on electroweak interactions and model building have been revised. Completely new is the chapter on conformality. As in the past, Frampton emphasizes formalism rather than experiments and provides sufficient detail for readers wishing to do their own calculations or pursue theoretical physics research: - gauge invariance, - quantization, - renormalization, - electroweak forces, - renormalization group, - quantum chromodynamics, - model building, - conformality. (orig.)
Gravitational Goldstone fields from affine gauge theory
Tresguerres, Romualdo; Mielke, Eckehard W.
2000-08-01
In order to facilitate the application of standard renormalization techniques, gravitation should be described, in the pure connection formalism, as a Yang-Mills theory of a certain spacetime group, say the Poincaré or the affine group. This embodies the translational as well as the linear connection. However, the coframe is not the standard Yang-Mills-type gauge field of the translations, since it lacks the inhomogeneous gradient term in the gauge transformations. By explicitly restoring this ``hidden'' piece within the framework of nonlinear realizations, the usual geometrical interpretation of the dynamical theory becomes possible, and in addition one can avoid the metric or coframe degeneracy which would otherwise interfere with the integrations within the path integral. We claim that nonlinear realizations provide the general mathematical scheme for the foundation of gauge theories of spacetime symmetries. When applied to construct the Yang-Mills theory of the affine group, tetrads become identified with nonlinear translational connections; the anholonomic metric no longer constitutes an independent gravitational potential, since its degrees of freedom reveal a correspondence to eliminateable Goldstone bosons. This may be an important advantage for quantization.
Light-induced gauge fields for ultracold atoms
Goldman, N.; Juzeliūnas, G.; Öhberg, P.; Spielman, I. B.
2014-12-01
Gauge fields are central in our modern understanding of physics at all scales. At the highest energy scales known, the microscopic universe is governed by particles interacting with each other through the exchange of gauge bosons. At the largest length scales, our Universe is ruled by gravity, whose gauge structure suggests the existence of a particle—the graviton—that mediates the gravitational force. At the mesoscopic scale, solid-state systems are subjected to gauge fields of different nature: materials can be immersed in external electromagnetic fields, but they can also feature emerging gauge fields in their low-energy description. In this review, we focus on another kind of gauge field: those engineered in systems of ultracold neutral atoms. In these setups, atoms are suitably coupled to laser fields that generate effective gauge potentials in their description. Neutral atoms ‘feeling’ laser-induced gauge potentials can potentially mimic the behavior of an electron gas subjected to a magnetic field, but also, the interaction of elementary particles with non-Abelian gauge fields. Here, we review different realized and proposed techniques for creating gauge potentials—both Abelian and non-Abelian—in atomic systems and discuss their implication in the context of quantum simulation. While most of these setups concern the realization of background and classical gauge potentials, we conclude with more exotic proposals where these synthetic fields might be made dynamical, in view of simulating interacting gauge theories with cold atoms.
Light-induced gauge fields for ultracold atoms
International Nuclear Information System (INIS)
Goldman, N; Juzeliūnas, G; Öhberg, P; Spielman, I B
2014-01-01
Gauge fields are central in our modern understanding of physics at all scales. At the highest energy scales known, the microscopic universe is governed by particles interacting with each other through the exchange of gauge bosons. At the largest length scales, our Universe is ruled by gravity, whose gauge structure suggests the existence of a particle—the graviton—that mediates the gravitational force. At the mesoscopic scale, solid-state systems are subjected to gauge fields of different nature: materials can be immersed in external electromagnetic fields, but they can also feature emerging gauge fields in their low-energy description. In this review, we focus on another kind of gauge field: those engineered in systems of ultracold neutral atoms. In these setups, atoms are suitably coupled to laser fields that generate effective gauge potentials in their description. Neutral atoms ‘feeling’ laser-induced gauge potentials can potentially mimic the behavior of an electron gas subjected to a magnetic field, but also, the interaction of elementary particles with non-Abelian gauge fields. Here, we review different realized and proposed techniques for creating gauge potentials—both Abelian and non-Abelian—in atomic systems and discuss their implication in the context of quantum simulation. While most of these setups concern the realization of background and classical gauge potentials, we conclude with more exotic proposals where these synthetic fields might be made dynamical, in view of simulating interacting gauge theories with cold atoms. (review article)
String field theory-inspired algebraic structures in gauge theories
International Nuclear Information System (INIS)
Zeitlin, Anton M.
2009-01-01
We consider gauge theories in a string field theory-inspired formalism. The constructed algebraic operations lead, in particular, to homotopy algebras of the related Batalin-Vilkovisky theories. We discuss an invariant description of the gauge fixing procedure and special algebraic features of gauge theories coupled to matter fields.
Canonical Yang-Mills field theory with invariant gauge-families
International Nuclear Information System (INIS)
Yokoyama, Kan-ichi
1978-01-01
A canonical Yang-Mills field theory with indefinite metric is presented on the basis of a covariant gauge formalism for quantum electrodynamics. As the first step of the formulation, a many-gauge-field problem, in which many massless Abelian-gauge fields coexist, is treated from a new standpoint. It is shown that only a single pair of a gaugeon field and its associated one can govern the gauge structure of the whole system. The result obtained is further extended to cases of non-Abelian gauge theories. Gauge parameters for respective components of the Yang-Mills fields are introduced as a group vector. There exists a q-number local gauge transformation which connects relevant fields belonging to the same invariant gauge family with one another in a manifestly covariant way. In canonical quantization, the Faddeev-Popov ghosts are introduced in order to guarantee the existence of a desirable physical subspace with positive semi-definite metric. As to treatment of the Faddeev-Popov ghosts, Kugo and Ojima's approach is adopted. Three supplementary conditions which are consistent with one another constrain the physical subspace. (author)
Relaxation methods for gauge field equilibrium equations
International Nuclear Information System (INIS)
Adler, S.L.; Piran, T.
1984-01-01
This article gives a pedagogical introduction to relaxation methods for the numerical solution of elliptic partial differential equations, with particular emphasis on treating nonlinear problems with delta-function source terms and axial symmetry, which arise in the context of effective Lagrangian approximations to the dynamics of quantized gauge fields. The authors present a detailed theoretical analysis of three models which are used as numerical examples: the classical Abelian Higgs model (illustrating charge screening), the semiclassical leading logarithm model (illustrating flux confinement within a free boundary or ''bag''), and the axially symmetric Bogomol'nyi-Prasad-Sommerfield monopoles (illustrating the occurrence of p topological quantum numbers in non-Abelian gauge fields). They then proceed to a self-contained introduction to the theory of relaxation methods and allied iterative numerical methods and to the practical aspects of their implementation, with attention to general issues which arise in the three examples. The authors conclude with a brief discussion of details of the numerical solution of the models, presenting sample numerical results
Energy Technology Data Exchange (ETDEWEB)
Yokoyama, Kan-ichi; Kubo, Reijiro
1974-12-01
The framework of the Nakanishi-Lautrup formalism should be enlarged by introducing a scalar dipole ghost field B(x), which is called gauge on field, together with its pair field. By taking free Lagrangian density, Free-field equations can be described. The vacuum is defined by using a neutral vector field U..mu..(x). The state-vector space is generated by the adjoining conjugates of U..mu..sup((+))(x), and auxiliary fields B(x), B/sub 1/(x) and B/sub 2/(x), which were introduced in the form of the Lagrangian density. The physical states can be defined by the supplementary conditions of the form B/sub 1/sup((+))(x) 1 phys>=B/sub 2/sup((+))(x) 1 phys>=0. It is seen that all the field equations and all the commutators are kept form-invariant, and that the gauge parameter ..cap alpha.. is transformed into ..cap alpha..' given by ..cap alpha..'=..cap alpha..+lambda, with epsilon unchanged. The Lagrangian density is specified only by the gauge invariant parameter epsilon. The gauge structure of theory has universal meaning over whole Abelian-gauge field. C-number gauge transformation and the gauge structure in the presence of interaction are also discussed.
Coding for Two Dimensional Constrained Fields
DEFF Research Database (Denmark)
Laursen, Torben Vaarbye
2006-01-01
a first order model to model higher order constraints by the use of an alphabet extension. We present an iterative method that based on a set of conditional probabilities can help in choosing the large numbers of parameters of the model in order to obtain a stationary model. Explicit results are given...... for the No Isolated Bits constraint. Finally we present a variation of the encoding scheme of bit-stuffing that is applicable to the class of checkerboard constrained fields. It is possible to calculate the entropy of the coding scheme thus obtaining lower bounds on the entropy of the fields considered. These lower...... bounds are very tight for the Run-Length limited fields. Explicit bounds are given for the diamond constrained field as well....
Dynamical chaos of nonabelian gauge fields
International Nuclear Information System (INIS)
Matinyan, S.G.
1985-01-01
A special class of the Yang - Mills field-the spatially homogeneous fields (Yan - Mills classical mechanics)-having no analog in the linear abelian electrodynamics is studied. Both the computer and analytical approaches show that such fields possess dynamical stochasticity, this allowing one to claim that the Yang - Mills classical equations without external sources represent a non-integrable system. The Higgs mechanism eliminates this stochasticity: at some expectation value of scalar field, a phase transition of disorder-order (confinement-deconfinement) type takes plce. The system with external sources behaves apparently analogously. A relation of the discovered stochasticity with the dimensional reduction mechanism in the macroscopic systems as well as with colour confinement is considered. It is shown that the presence of the random (Gaussian) currents in vacuum leads to confinement of fields generated by those currents. Attention is paid to the possible manifestation of the revealed stochasticity of the classical non-abelian gauge fields in the multiple hadrnoproduction processes which apparently reflect the universal stochastic regularities typical of the systems of quite different nature
Dynamical chaos of nonabelian gauge fields
Energy Technology Data Exchange (ETDEWEB)
Matinyan, S G
1985-01-01
A special class of the Yang - Mills field-the spatially homogeneous fields (Yan - Mills classical mechanics)-having no analog in the linear abelian electrodynamics is studied. Both the computer and analytical approaches show that such fields possess dynamical stochasticity, this allowing one to claim that the Yang - Mills classical equations without external sources represent a non-integrable system. The Higgs mechanism eliminates this stochasticity: at some expectation value of scalar field, a phase transition of disorder-order (confinement-deconfinement) type takes plce. The system with external sources behaves apparently analogously. A relation of the discovered stochasticity with the dimensional reduction mechanism in the macroscopic systems as well as with colour confinement is considered. It is shown that the presence of the random (Gaussian) currents in vacuum leads to confinement of fields generated by those currents. Attention is paid to the possible manifestation of the revealed stochasticity of the classical non-abelian gauge fields in the multiple hadrnoproduction processes which apparently reflect the universal stochastic regularities typical of the systems of quite different nature.
Some physico-geometrical remarks on gauge fields
International Nuclear Information System (INIS)
Ikeda, S.
1976-01-01
The gauge fields introduced to accomplish gauge invariance under Poincare and Weyl gauge transformations in general relativity are found a new to be absorbed into the covariant derivative operators. Some torsional properties associated with them are also discussed in connection with the principle of minimally coupling and the equivalence principle
Self-constrained inversion of potential fields
Paoletti, V.; Ialongo, S.; Florio, G.; Fedi, M.; Cella, F.
2013-11-01
We present a potential-field-constrained inversion procedure based on a priori information derived exclusively from the analysis of the gravity and magnetic data (self-constrained inversion). The procedure is designed to be applied to underdetermined problems and involves scenarios where the source distribution can be assumed to be of simple character. To set up effective constraints, we first estimate through the analysis of the gravity or magnetic field some or all of the following source parameters: the source depth-to-the-top, the structural index, the horizontal position of the source body edges and their dip. The second step is incorporating the information related to these constraints in the objective function as depth and spatial weighting functions. We show, through 2-D and 3-D synthetic and real data examples, that potential field-based constraints, for example, structural index, source boundaries and others, are usually enough to obtain substantial improvement in the density and magnetization models.
Topics in gravitation and gauge fields
International Nuclear Information System (INIS)
Leen, T.K.
1982-01-01
The theoretical studies presented here address three distinct topics. The first deals with quantum-mechanical effects of classical gravitational radiation. Specifically, the use of the interstellar medium itself as a remote quantum-mechanical detector of gravitational waves is investigated. This study is motivated by the presumed existence of atomic hydrogen in the vicinity of astrophysical sources of gravitational radiation. Space-time curvature produces uniquely identifiable shifts in atomic hydrogen energy levels. The oscillating level shifts induced by a passing gravitational wave could conceivably be detected spectroscopically. Accordingly the level shifts for both low-lying and highly excited states of single electron atoms immersed in gravitational radiation have been studied. The second two topics deal with the theory of quantized fields on curved space-times. In the first of these studies, a naive model of cosmological baryon synthesis is examined. The model incorporates a hard CP violation as well as a baryon (and lepton) non-conserving interaction and is thus capable of generating an excess of matter over antimatter. The time dependent background geometry of the early universe drives the interaction producing net excess of baryon/lepton pairs. In the final topic, the question of renormalizability of non-Abelian gauge fields theories in a general curved space-time is addressed. All modern theories of elementary particle physics are gauge theories and one would like to know if their perturbative expansions continue to be well defined (i.e. renormalizable) on curved backgrounds. In general, one is interested in knowing if field theories renormalizable in Minkowski space remain so in a general curved space-time
Vacuum structure of the SU(3) gauge field theory in the Coulomb gauge
International Nuclear Information System (INIS)
Yee, J.H.; Viswanathan, K.S.
1978-01-01
The SU(3) gauge field is studied in the Coulomb gauge. The Gribov ambiguities arising in the Coulomb gauge are analysed. Restricting to a class of spherically symmetric vacua it is shown that there exist non-trivial vacua characterized by a topological number eta=0, +-1/2, and +-2. This must be contrasted with the spherically symmetric SU(2) vacua which are characterized by eta=0, +-1/2. (Auth.)
International Nuclear Information System (INIS)
Cheng Hung; Tsai Ercheng
1986-01-01
We give a correspondence formula which equates transition amplitudes in a quantum gauge field theory without ghost fields to those in a quantum theory with the gauge fields covariantly quantized and coupled to ghost fields. (orig.)
Metric interpretation of gauge fields in noncommutative geometry
International Nuclear Information System (INIS)
Martinetti, P.
2007-01-01
We shall give an overview of the metric interpretation of gauge fields in noncommutative geometry, via Connes distance formula. Especially we shall focus on the Higgs fields in the standard model, and gauge fields in various models of fiber bundle. (author)
Localization of abelian gauge fields on thick branes
Energy Technology Data Exchange (ETDEWEB)
Vaquera-Araujo, Carlos A. [Universidad de Colima, Facultad de Ciencias, CUICBAS, Colima (Mexico); Corradini, Olindo [Universidad Autonoma de Chiapas, Ciudad Universitaria, Facultad de Ciencias en Fisica y Matematicas, Tuxtla Gutierrez (Mexico); Universita di Modena e Reggio Emilia, Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Modena (Italy)
2015-02-01
In this work, we explore a mechanism for abelian gauge field localization on thick branes based on a five-dimensional Stueckelberg-like action. A normalizable zero mode is found through the identification of a suitable coupling function between the brane and the gauge field. The same mechanism is studied for the localization of the abelian Kalb-Ramond field. (orig.)
Vortex operators in gauge field theories
International Nuclear Information System (INIS)
Polchinski, J.
1980-07-01
Several related aspects of the 't Hooft vortex operator are studied. The current picture of the vacuum of quantum chromodynamics, the idea of dual field theories, and the idea of the vortex operator are reviewed first. The Abelian vortex operator written in terms of elementary fields and the calculation of its Green's functions are considered. A two-dimensional solvable model of a Dirac string is presented. The expression of the Green's functions more neatly in terms of Wu and Yang's geometrical idea of sections is addressed. The renormalization of the Green's functions of two kinds of Abelian looplike operators, the Wilson loop and the vortex operator, is studied; for both operators only an overall multiplicative renormalization is needed. In the case of the vortex this involves a surprising cancellation. Next, the dependence of the Green's functions of the Wilson and 't Hooft operators on the nature of the vacuum is discussed. The cluster properties of the Green's functions are emphasized. It is seen that the vortex operator in a massive Abelian theory always has surface-like clustering. The form of Green's functions in terms of Feynman graphs is the same in Higgs and symmetric phases; the difference appears in the sum over all tadpole trees. Finally, systems having fields in the fundamental representation are considered. When these fields enter only weakly into the dynamics, a vortex-like operator is anticipated. Any such operator can no longer be local looplike, but must have commutators at long range. A U(1) lattice gauge theory with two matter fields, one singly charged (fundamental) and one doubly charged (adjoint), is examined. When the fundamental field is weakly coupled, the expected phase transitions are found. When it is strongly coupled, the operator still appears to be a good order parameter, a discontinuous change in its behavior leads to a new phase transition. 18 figures
Gauge-invariant Yang-Mills fields and the role of Lorentz gauge condition
International Nuclear Information System (INIS)
Skachkov, N.B.; Shevchenko, O.Yu.
1985-01-01
A new class of gauge-invariant (G.I.) fields is constructed. The inversion formulae that express these fields through the G.I. strength tensor are obtained. It is shown that for the G.I. fields the Lorentz gauge condition appears as the secondary constraint. These fields coincide with the usual ones in some definite gauges. The Dyson-Schwinger equations for the G.I. spinor propagator are derived. It is found that in QED this propagator has a simple pole singularity (p-m) -1 in the infrared limit
Non-Abelian gauge fields in two spatial dimensions
International Nuclear Information System (INIS)
Hagen, C.R.
1987-01-01
Generalizing an earlier work on the Abelian case the most general non-Abelian gauge theory in two spatial dimensions is derived. It is shown that local gauge invariance leads to a new term in the action which in turn requires that the gauge current operator have a part which is bilinear in the non-Abelian gauge field-strength tensor. Although a radiation (or axial) gauge quantization is possible, this approach is found not to yield the maximal set of commutation relations among the basic fields. The latter goal can be accomplished only by a rather unusual gauge choice which has not previously been studied. Quantization conditions on the coupling constant implied by invariance under large gauge transformations are also derived
Vortex operators in gauge field theories
International Nuclear Information System (INIS)
Polchinski, J.G.
1980-01-01
We study several related aspects of the t Hooft vortex operator. The first chapter reviews the current picture of the vacuum of quantum chromodynamics, the idea of dual field theories, and the idea of the vortex operator. The second chapter deals with the Abelian vortex operator written in terms of elementary fields and with the calculation of its Green's functions. The Dirac veto problem appears in a new guise. We present a two dimensional solvable model of a Dirac string. This leads us to a new solution of the veto problem; we discuss its extension to four dimensions. We then show how the Green's functions can be expressed more neatly in terms of Wu and Yang's geometrical idea of sections. In the third chapter we discuss the dependence of the Green's functions of the Wilson and t Hooft operators on the nature of the vacuum. In the fourth chapter we consider systems which have fields in the fundamental representation, so that there are no vortex operators. When these fields enter only weakly into the dynamics, as is the case in QCD and in real superconductors, we would expect to be able to define a vortex-like operator. We show that any such operator can no longer be local looplike, but must have commutators at long range. We can still find an operator with useful properties, its cluster property, though more complicated than that of the usual vortex operator, still appears to distinguish Higgs, confining and perturbative phases. To test this, we consider a U(1) lattice gauge theory with two matter fields, one singly charged (fundamental) and one doubly charged (adjoint)
International Nuclear Information System (INIS)
Wang Fan; Chen Xiangsong; Lue Xiaofu; Sun Weiming; Goldman, T.
2010-01-01
It is unavoidable to deal with the quark and gluon momentum and angular momentum contributions to the nucleon momentum and spin in the study of nucleon internal structure. However, we never have the quark and gluon momentum, orbital angular momentum and gluon spin operators which satisfy both the gauge invariance and the canonical momentum and angular momentum commutation relations. The conflicts between the gauge invariance and canonical quantization requirement of these operators are discussed. A new set of quark and gluon momentum, orbital angular momentum and spin operators, which satisfy both the gauge invariance and canonical momentum and angular momentum commutation relations, are proposed. The key point to achieve such a proper decomposition is to separate the gauge field into the pure gauge and the gauge covariant parts. The same conflicts also exist in QED and quantum mechanics and have been solved in the same manner. The impacts of this new decomposition to the nucleon internal structure are discussed.
Multigrid methods for the computation of propagators in gauge fields
International Nuclear Information System (INIS)
Kalkreuter, T.
1992-11-01
In the present work generalizations of multigrid methods for propagators in gauge fields are investigated. We discuss proper averaging operations for bosons and for staggered fermions. An efficient algorithm for computing C numerically is presented. The averaging kernels C can be used not only in deterministic multigrid computations, but also in multigrid Monte Carlo simulations, and for the definition of block spins and blocked gauge fields in Monte Carlo renormalization group studies of gauge theories. Actual numerical computations of kernels and propagators are performed in compact four-dimensional SU(2) gauge fields. (orig./HSI)
Gauge principle for hyper(para) fields
Energy Technology Data Exchange (ETDEWEB)
Govorkov, A.B. (Joint Inst. for Nuclear Research, Dubna (USSR))
1983-04-01
A special representation for parafields is considered which is based on the use of the Clifford hypernumbers. The principle of gauge invariance under hypercomplex phase transformations of parafields is formulated. A special role of quaternion hyperfields and corresponding Yang-Mills lagrangian with the gauge SO(3)-symmetry is pointed out.
Nonabelian gauge fields in the background of magnetic strings
International Nuclear Information System (INIS)
Wieczorek, E.
1993-01-01
Quantized nonabelian gauge fields are studied in the external classical background of a linear magnetic string. The determination of the gauge field propagator demands a specification of the string by suitable physical limiting procedures. The vacuum energy density is obtained after transforming the background problem into a Casimir problem. (orig.)
Gauge field entanglement in Kitaev's honeycomb model
Dóra, Balázs; Moessner, Roderich
2018-01-01
A spin fractionalizes into matter and gauge fermions in Kitaev's spin liquid on the honeycomb lattice. This follows from a Jordan-Wigner mapping to fermions, allowing for the construction of a minimal entropy ground-state wave function on the cylinder. We use this to calculate the entanglement entropy by choosing several distinct partitionings. First, by partitioning an infinite cylinder into two, the -ln2 topological entanglement entropy is reconfirmed. Second, the reduced density matrix of the gauge sector on the full cylinder is obtained after tracing out the matter degrees of freedom. This allows for evaluating the gauge entanglement Hamiltonian, which contains infinitely long-range correlations along the symmetry axis of the cylinder. The matter-gauge entanglement entropy is (Ny-1 )ln2 , with Ny the circumference of the cylinder. Third, the rules for calculating the gauge sector entanglement of any partition are determined. Rather small correctly chosen gauge partitions can still account for the topological entanglement entropy in spite of long-range correlations in the gauge entanglement Hamiltonian.
Mean field with corrections in lattice gauge theory
International Nuclear Information System (INIS)
Flyvbjerg, H.; Zuber, J.B.; Lautrup, B.
1981-12-01
A systematic expansion of the path integral for lattice gauge theory is performed around the mean field solution. In this letter the authors present the results for the pure gauge groups Z(2), SU(2) and SO(3). The agreement with Monte Carlo calculations is excellent. For the discrete group the calculation is performed with and without gauge fixing, whereas for the continuous groups gauge fixing is mandatory. In the case of SU(2) the absence of a phase transition is correctly signalled by mean field theory. (Auth.)
On the hyperbolicity of Einstein's and other gauge field equations
International Nuclear Information System (INIS)
Friedrich, H.
1985-01-01
It is shown that Einstein's vacuum field equations (respectively the conformal vacuum field equations) in a frame formalism imply a symmetric hyperbolic system of ''reduce'' propagation equations for any choice of coordinate system and frame field (and conformal factor). Certain freely specifiable ''gauge source'' functions occurring in the reduced equations reflect the choice of gauge. Together with the initial data they determine the gauge uniquely. Their choice does not affect the isometry class (conformal class) of a solution of an initial value problem. By the same method symmetric hyperbolic propagation equations are obtained from other gauge field equations, irrespective of the gauge. Using the concept of source functions one finds that Einstein's field equation, considered as second order equations for the metric coefficients, are of wave equation type in any coordinate system. (orig.)
Renormalization of nonabelian gauge theories with tensor matter fields
International Nuclear Information System (INIS)
Lemes, Vitor; Renan, Ricardo; Sorella, Silvio Paolo
1996-03-01
The renormalizability of a nonabelian model describing the coupling between antisymmetric second rank tensor matter fields and Yang-Mills gauge fields is discussed within the BRS algebraic framework. (author). 12 refs
Noncommutative gauge field theories: A no-go theorem
International Nuclear Information System (INIS)
Chaichian, M.; Tureanu, A.; Presnajder, P.; Sheikh-Jabbari, M.M.
2001-06-01
Studying the mathematical structure of the noncommutative groups in more detail, we prove a no-go theorem for the noncommutative gauge theories. According to this theorem, the closure condition of the gauge algebra implies that: 1) the local noncommutative u(n) algebra only admits the irreducible nxn matrix-representation. Hence the gauge fields, as elements of the algebra, are in nxn matrix form, while the matter fields can only be either in fundamental, adjoint or singlet states; 2) for any gauge group consisting of several simple group factors, the matter fields can transform nontrivially under at most two noncommutative group factors. In other words, the matter fields cannot carry more than two simple noncommutative gauge group charges. This no-go theorem imposes strong restrictions on the construction of the noncommutative version of the Standard Model and in resolving the standing problem of charge quantization in noncommutative QED. (author)
Blockspin transformations for finite temperature field theories with gauge fields
International Nuclear Information System (INIS)
Kerres, U.
1996-08-01
A procedure is proposed to study quantum field theories at zero or at finite temperature by a sequence of real space renormalization group (RG) or blockspin transformations. They transform to effective theories on coarser and coarser lattices. The ultimate aim is to compute constraint effective potentials, i.e. the free energy as a function of suitable order parameters. From the free energy one can read off the thermodynamic behaviour of the theory, in particular the existence and nature of phase transitions. In a finite temperature field theory one begins with either one or a sequence of transformations which transform the original theory into an effective theory on a three-dimensional lattice. Its effective action has temperature dependent coefficients. Thereafter one may proceed with further blockspin transformations of the three-dimensional theory. Assuming a finite volume, this can in principle be continued until one ends with a lattice with a single site. Its effective action is the constraint effective potential. In each RG-step, an integral over the high frequency part of the field, also called the fluctuation field, has to be performed. This is done by perturbation theory. It requires the knowledge of bare fluctuation field propagators and of interpolation operators which enter into the vertices. A detailed examination of these quantities is presented for scalar fields, abelian gauge fields and for Higgs fields, finite temperature is admitted. The lattice perturbation theory is complicated because the bare lattice propagators are complicated. This is due to a partial loss of translation invariance in each step. Therefore the use of translation invariant cutoffs in place of a lattice is also discussed. In case of gauge fields this is only possible as a continuum version of the blockspin method. (orig.)
Manipulating novel quantum phenomena using synthetic gauge fields
Zhang, Shao-Liang; Zhou, Qi
2017-11-01
The past few years have seen fascinating progress in the creation and utilization of synthetic gauge fields for charge-neutral ultracold atoms. Whereas the synthesis of gauge fields in itself is readily interesting, it is more exciting to explore the new era that will be brought by the interplay between synthetic gauge fields and many other degrees of freedom of highly tunable ultracold atoms. This topical review surveys recent developments in using synthetic gauge fields to manipulate novel quantum phenomena that are not easy to access in other systems. We first summarize current experimental methods of creating synthetic gauge fields, including the use of Raman schemes, shaken lattices, and Raman-dressed lattices. We then discuss how synthetic gauge fields bring new physics to non-interacting systems, including degenerate single-particle ground states, quartic dispersions, topological band structures in lattices, and synthetic dimensions. As for interacting systems, we focus on novel quantum many-body states and quantum macroscopic phenomena induced by interactions in the presence of unconventional single-particle dispersions. For bosons, we discuss how a quartic dispersion leads to non-condensed bosonic states at low temperatures and at the ground state. For fermions, we discuss chiral superfluids in the presence of attractive s-wave interaction, where high partial-wave interactions are not required. Finally, we discuss the challenges in current experiments, and conclude with an outlook for what new exciting developments synthetic gauge fields may bring us in the near future.
Massive Abelian gauge fields coupled with nonconserved currents
International Nuclear Information System (INIS)
Nakazato, Hiromichi; Namiki, Mikio; Yamanaka, Yoshiya; Yokoyama, Kan-ichi.
1985-04-01
A massive Abelian gauge field coupled with a nonconserved mass-changing current is described within the framework of canonical quantum theory with indefinite metric. In addition to the conventional Lagrange multiplier fields, another ghost field is introduced to preserve gauge invariance and unitarity of a physical S-matrix in the case of the nonconserved current. The renormalizability of the theory is explicitly shown in the sense of superpropagator approach for nonpolynomial Lagrangian theories. (author)
Massive and massless gauge fields of any spin and symmetry
International Nuclear Information System (INIS)
Hussain, F.; Jarvis, P.D.
1988-05-01
An analysis of the BRST approach to massive and massless gauge fields of any spin and symmetry is presented. Previous results on massless gauge fields are extended to totally antisymmetric massless tensors and Kaehler-Dirac particles. Two methods for arriving at a BRST invariant, massive theory from the corresponding massless one are discussed. The first allows for an interpretation in terms of dimensional reduction, while the second keeps the BRST operator of the massless theory, but employs gauge invariant fields. (author). 10 refs
Towards a unified picture for gauge and Higgs fields
International Nuclear Information System (INIS)
Mecklenburg, W.
1981-01-01
A scheme for a geometrical unification of gauge and Higgs fields, previously given for SU 2 , is generalized to include arbitrary semisimple gauge groups. Gauge and physical Higgs fields appear as different components of the same tensor in a high dimensional manifold, the higher dimensions being comprised by the group coordinates. Their respective inhomogeneous transformation behaviour is derived from the same principle. The number of Higgs fields is restricted. The form of the Higgs potential is fixed and the mass of the Higgs particle is predicted in terms of the vector boson mass. (author)
A study of fermions coupled to gauge and gravitational fields on a cylinder
Energy Technology Data Exchange (ETDEWEB)
Lano, R.P. [Iowa Univ., Iowa City, IA (United States). Dept. of Physics and Astronomy; Rodgers, V.G.J. [Iowa Univ., Iowa City, IA (United States). Dept. of Physics and Astronomy
1995-03-06
Fermions on a cylinder coupled to background gravitation and gauge fields are examined by studying the geometric action associated with the symmetries of such a system. We are able to show that the gauge coupling constant is constrained to a value of 1/N where N is an integer. Furthermore, in direct analogy with a Yang-Mills theory a new gravitational theory is introduced which couples to the fermions by promoting the coadjoint vector of the diffeomorphism sector to a dynamical variable. The classical dynamics of this theory are examined by displaying its symplectic structure and showing that it is equivalent to a one-dimensional system. ((orig.)).
Equivalence between the Lovelock-Cartan action and a constrained gauge theory
International Nuclear Information System (INIS)
Junqueira, O.C.; Sadovski, G.; Santos, T.R.S.; Sobreiro, R.F.; Pereira, A.D.; Tomaz, A.A.
2017-01-01
We show that the four-dimensional Lovelock-Cartan action can be derived from a massless gauge theory for the SO(1, 3) group with an additional BRST trivial part. The model is originally composed of a topological sector and a BRST exact piece and has no explicit dependence on the metric, the vierbein or a mass parameter. The vierbein is introduced together with a mass parameter through some BRST trivial constraints. The effect of the constraints is to identify the vierbein with some of the additional fields, transforming the original action into the Lovelock-Cartan one. In this scenario, the mass parameter is identified with Newton's constant, while the gauge field is identified with the spin connection. The symmetries of the model are also explored. Moreover, the extension of the model to a quantum version is qualitatively discussed. (orig.)
Equivalence between the Lovelock-Cartan action and a constrained gauge theory
Energy Technology Data Exchange (ETDEWEB)
Junqueira, O.C.; Sadovski, G.; Santos, T.R.S.; Sobreiro, R.F. [UFF-Universidade Federal Fluminense, Instituto de Fisica, Niteroi, RJ (Brazil); Pereira, A.D. [UERJ-Universidade Estadual do Rio de Janeiro, Departamento de Fisica Teorica, Rio de Janeiro, RJ (Brazil); Tomaz, A.A. [UFF-Universidade Federal Fluminense, Instituto de Fisica, Niteroi, RJ (Brazil); CBPF-Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro, RJ (Brazil)
2017-04-15
We show that the four-dimensional Lovelock-Cartan action can be derived from a massless gauge theory for the SO(1, 3) group with an additional BRST trivial part. The model is originally composed of a topological sector and a BRST exact piece and has no explicit dependence on the metric, the vierbein or a mass parameter. The vierbein is introduced together with a mass parameter through some BRST trivial constraints. The effect of the constraints is to identify the vierbein with some of the additional fields, transforming the original action into the Lovelock-Cartan one. In this scenario, the mass parameter is identified with Newton's constant, while the gauge field is identified with the spin connection. The symmetries of the model are also explored. Moreover, the extension of the model to a quantum version is qualitatively discussed. (orig.)
Equivalence between the Lovelock-Cartan action and a constrained gauge theory
Junqueira, O. C.; Pereira, A. D.; Sadovski, G.; Santos, T. R. S.; Sobreiro, R. F.; Tomaz, A. A.
2017-04-01
We show that the four-dimensional Lovelock-Cartan action can be derived from a massless gauge theory for the SO(1, 3) group with an additional BRST trivial part. The model is originally composed of a topological sector and a BRST exact piece and has no explicit dependence on the metric, the vierbein or a mass parameter. The vierbein is introduced together with a mass parameter through some BRST trivial constraints. The effect of the constraints is to identify the vierbein with some of the additional fields, transforming the original action into the Lovelock-Cartan one. In this scenario, the mass parameter is identified with Newton's constant, while the gauge field is identified with the spin connection. The symmetries of the model are also explored. Moreover, the extension of the model to a quantum version is qualitatively discussed.
Extended monopoles in gauge field theories
International Nuclear Information System (INIS)
Horvath, Z.; Palla, L.
1977-04-01
The paper gives a review of the 't Hooft monopole and briefly discusses the general topological considerations connected with monopoles. A method is presented for constructing explicit monopole solutions in any gauge theory. Some stability questions and time-dependent problems are also considered
Two-time physics with gravitational and gauge field backgrounds
International Nuclear Information System (INIS)
Bars, Itzhak
2000-01-01
It is shown that all possible gravitational, gauge and other interactions experienced by particles in ordinary d dimensions (one time) can be described in the language of two-time physics in a spacetime with d+2 dimensions. This is obtained by generalizing the world line formulation of two-time physics by including background fields. A given two-time model, with a fixed set of background fields, can be gauged fixed from d+2 dimensions to (d-1)+1 dimensions to produce diverse one-time dynamical models, all of which are dually related to each other under the underlying gauge symmetry of the unified two-time theory. To satisfy the gauge symmetry of the two-time theory the background fields must obey certain coupled differential equations that are generally covariant and gauge invariant in the target (d+2)-dimensional spacetime. The gravitational background obeys a closed homothety condition while the gauge field obeys a differential equation that generalizes a similar equation derived by Dirac in 1936. Explicit solutions to these coupled equations show that the usual gravitational, gauge, and other interactions in d dimensions may be viewed as embedded in the higher (d+2)-dimensional space, thus displaying higher spacetime symmetries that otherwise remain hidden
Gauge fields in algebraically special space-times
International Nuclear Information System (INIS)
Torres del Castillo, G.F.
1985-01-01
It is shown that in an algebraically special space-time which admits a congruence of null strings, a source-free gauge field aligned with the congruence is determined by a matrix potential which has to satisfy a second-order differential equation with quadratic nonlinearities. The Einstein--Yang--Mills equations are then reduced to a scalar and two matrix equations. In the case of self-dual gauge fields in a self-dual space-time, the existence of an infinite set of conservation laws, of an associated linear system, and of infinitesimal Baecklund transformations is demonstrated. All the results apply for an arbitrary gauge group
Hot gauge field properties from the thermal variational principle
International Nuclear Information System (INIS)
Schroeder, Y.; Schulz, H.
1995-10-01
A Feynman-Jensen version of the thermal variational principle is applied to hot gauge fields, abelian as well as nonabelian: scalar electrodynamics (without scalar self-coupling) and the gluon plasma. The perturbatively known self-energies are shown to derive by variation from a free quadratic (''gaussian'') trial Lagrangian. Independence of the covariant gauge fixing parameter is reached (within the order g 2 studies and for scalar ED) after a reformulation of the partition function such that it depends on only even powers of the gauge field. This way, however, the potential non-perturbative power of the calculus seems to be ruined. (orig.)
Dual geometric-gauge field aspects of gravity
International Nuclear Information System (INIS)
Huei Peng; Wang, K.
1992-01-01
We propose that the geometric and standard gauge field aspects of gravity are equally essential for a complete description of gravity and can be reconciled. We show that this dualism of gravity resolves the dimensional Newtonian constant problem in both quantum gravity and unification schemes involving gravity (i.e., the Newtonian constant is no longer the coupling constant in the gauge aspect of gravity) and reveals the profound similarity between gravity and other fields. 23 refs., 3 tabs
On quantization of the electromagnetic field in radiation gauge
International Nuclear Information System (INIS)
Burzynski, A.
1982-01-01
This paper contains a detailed description of quantization of the electromagnetic field (in radiation gauge) and quantization of some basic physical variables connected with radiation field as energy, momentum and spin. The dynamics of the free quantum radiation field and the field interacting with external classical sources is described. The canonical formalism is not used explicity. (author)
Near-field photon wave mechanics in the Lorenz gauge
International Nuclear Information System (INIS)
Keller, Ole
2007-01-01
Optical near-field interactions are studied theoretically in the perspective of photon wave mechanics paying particular attention to the dynamics in the wave-vector time domain. A unitary transformation is used to replace the scalar and longitudinal photon variables by so-called near-field and gauge photon variables. Dynamical equations are established for these types of photon variables, and it is shown that these equations are invariant against gauge transformations within the Lorenz gauge. The near-field photon is absent in the free-field limit, and the gauge photon can be eliminated by a suitable gauge transformation. Implicit solutions for the near-field, gauge, and transverse photon variables are obtained and discussed. The general theory is applied to an investigation of transverse photon propagation in a uniform solid-state plasma dominated by the diamagnetic field-matter interaction. It is found that the diamagnetic response can be incorporated in a quantum mechanical wave equation for a massive transverse photon. The Compton wave number of the massive photon equals the plasma wave number of the electron system. A dynamical equation describing the emission of a massive transverse photon from a mesoscopic source embedded in the plasma is finally established
Remarks on an equation common to Weyl's gauge field, Yang-Mills field and Toda lattice
International Nuclear Information System (INIS)
Nishioka, M.
1984-01-01
In this letter a remark is presented on an equation of a gauge-invariant Weyl's gauge field and it is shown that the equation is common to Yang's approach to the self-duality condition for SU 2 gauge field and the simplest Toda lattice
Hyperunified field theory and gravitational gauge-geometry duality
International Nuclear Information System (INIS)
Wu, Yue-Liang
2018-01-01
A hyperunified field theory is built in detail based on the postulates of gauge invariance and coordinate independence along with the conformal scaling symmetry. All elementary particles are merged into a single hyper-spinor field and all basic forces are unified into a fundamental interaction governed by the hyper-spin gauge symmetry SP(1, D h - 1). The dimension D h of hyper-spacetime is conjectured to have a physical origin in correlation with the hyper-spin charge of elementary particles. The hyper-gravifield fiber bundle structure of biframe hyper-spacetime appears naturally with the globally flat Minkowski hyper-spacetime as a base spacetime and the locally flat hyper-gravifield spacetime as a fiber that is viewed as a dynamically emerged hyper-spacetime characterized by a non-commutative geometry. The gravitational origin of gauge symmetry is revealed with the hyper-gravifield that plays an essential role as a Goldstone-like field. The gauge-gravity and gravity-geometry correspondences bring about the gravitational gauge-geometry duality. The basic properties of hyperunified field theory and the issue on the fundamental scale are analyzed within the framework of quantum field theory, which allows us to describe the laws of nature in deriving the gauge gravitational equation with the conserved current and the geometric gravitational equations of Einstein-like type and beyond. (orig.)
Hyperunified field theory and gravitational gauge-geometry duality
Energy Technology Data Exchange (ETDEWEB)
Wu, Yue-Liang [International Centre for Theoretical Physics Asia-Pacific (ICTP-AP), Beijing (China); Chinese Academy of Sciences, Institute of Theoretical Physics, Beijing (China); University of Chinese Academy of Sciences (UCAS), Beijing (China)
2018-01-15
A hyperunified field theory is built in detail based on the postulates of gauge invariance and coordinate independence along with the conformal scaling symmetry. All elementary particles are merged into a single hyper-spinor field and all basic forces are unified into a fundamental interaction governed by the hyper-spin gauge symmetry SP(1, D{sub h} - 1). The dimension D{sub h} of hyper-spacetime is conjectured to have a physical origin in correlation with the hyper-spin charge of elementary particles. The hyper-gravifield fiber bundle structure of biframe hyper-spacetime appears naturally with the globally flat Minkowski hyper-spacetime as a base spacetime and the locally flat hyper-gravifield spacetime as a fiber that is viewed as a dynamically emerged hyper-spacetime characterized by a non-commutative geometry. The gravitational origin of gauge symmetry is revealed with the hyper-gravifield that plays an essential role as a Goldstone-like field. The gauge-gravity and gravity-geometry correspondences bring about the gravitational gauge-geometry duality. The basic properties of hyperunified field theory and the issue on the fundamental scale are analyzed within the framework of quantum field theory, which allows us to describe the laws of nature in deriving the gauge gravitational equation with the conserved current and the geometric gravitational equations of Einstein-like type and beyond. (orig.)
Hyperunified field theory and gravitational gauge-geometry duality
Wu, Yue-Liang
2018-01-01
A hyperunified field theory is built in detail based on the postulates of gauge invariance and coordinate independence along with the conformal scaling symmetry. All elementary particles are merged into a single hyper-spinor field and all basic forces are unified into a fundamental interaction governed by the hyper-spin gauge symmetry SP(1, D_h-1). The dimension D_h of hyper-spacetime is conjectured to have a physical origin in correlation with the hyper-spin charge of elementary particles. The hyper-gravifield fiber bundle structure of biframe hyper-spacetime appears naturally with the globally flat Minkowski hyper-spacetime as a base spacetime and the locally flat hyper-gravifield spacetime as a fiber that is viewed as a dynamically emerged hyper-spacetime characterized by a non-commutative geometry. The gravitational origin of gauge symmetry is revealed with the hyper-gravifield that plays an essential role as a Goldstone-like field. The gauge-gravity and gravity-geometry correspondences bring about the gravitational gauge-geometry duality. The basic properties of hyperunified field theory and the issue on the fundamental scale are analyzed within the framework of quantum field theory, which allows us to describe the laws of nature in deriving the gauge gravitational equation with the conserved current and the geometric gravitational equations of Einstein-like type and beyond.
Lattice Gauge Field Theory and Prismatic Sets
DEFF Research Database (Denmark)
Akyar, Bedia; Dupont, Johan Louis
as and in particular the latter we use to study lattice gauge theory in the sense of Phillips and Stone. Thus for a Lie group and a set of parallel transport functions defining the transition over faces of the simplices, we define a classifying map from the prismatic star to a prismatic version of the classifying......We study prismatic sets analogously to simplicial sets except that realization involves prisms, i.e., products of simplices rather than just simplices. Particular examples are the prismatic subdivision of a simplicial set and the prismatic star of . Both have the same homotopy type...
Non-Abelian gauge field theory in scale relativity
International Nuclear Information System (INIS)
Nottale, Laurent; Celerier, Marie-Noeelle; Lehner, Thierry
2006-01-01
Gauge field theory is developed in the framework of scale relativity. In this theory, space-time is described as a nondifferentiable continuum, which implies it is fractal, i.e., explicitly dependent on internal scale variables. Owing to the principle of relativity that has been extended to scales, these scale variables can themselves become functions of the space-time coordinates. Therefore, a coupling is expected between displacements in the fractal space-time and the transformations of these scale variables. In previous works, an Abelian gauge theory (electromagnetism) has been derived as a consequence of this coupling for global dilations and/or contractions. We consider here more general transformations of the scale variables by taking into account separate dilations for each of them, which yield non-Abelian gauge theories. We identify these transformations with the usual gauge transformations. The gauge fields naturally appear as a new geometric contribution to the total variation of the action involving these scale variables, while the gauge charges emerge as the generators of the scale transformation group. A generalized action is identified with the scale-relativistic invariant. The gauge charges are the conservative quantities, conjugates of the scale variables through the action, which find their origin in the symmetries of the ''scale-space.'' We thus found in a geometric way and recover the expression for the covariant derivative of gauge theory. Adding the requirement that under the scale transformations the fermion multiplets and the boson fields transform such that the derived Lagrangian remains invariant, we obtain gauge theories as a consequence of scale symmetries issued from a geometric space-time description
Inflationary dynamics of kinetically-coupled gauge fields
DEFF Research Database (Denmark)
Ferreira, Ricardo J. Z.; Ganc, Jonathan
2015-01-01
We investigate the inflationary dynamics of two kinetically-coupled massless U(1) gauge fields with time-varying kinetic-term coefficients. Ensuring that the system does not have strongly coupled regimes shrinks the parameter space. Also, we further restrict ourselves to systems that can be quant......We investigate the inflationary dynamics of two kinetically-coupled massless U(1) gauge fields with time-varying kinetic-term coefficients. Ensuring that the system does not have strongly coupled regimes shrinks the parameter space. Also, we further restrict ourselves to systems that can...... be quantized using the standard creation, annihilation operator algebra. This second constraint limits us to scenarios where the system can be diagonalized into the sum of two decoupled, massless, vector fields with a varying kinetic-term coefficient. Such a system might be interesting for magnetogenesis...... because of how the strong coupling problem generalizes. We explore this idea by assuming that one of the gauge fields is the Standard Model U(1) field and that the other dark gauge field has no particles charged under its gauge group. We consider whether it would be possible to transfer a magnetic field...
Interaction of orientable object fields with gauge fields
International Nuclear Information System (INIS)
Gitman, D M; Shelepin, A L
2011-01-01
We consider a scalar field f(g) on the Poincaré group M(3, 1). This scalar field describes objects that are characterized by a position x and an orientation z, g=(x,z). The field f(x, z) admits two kinds of transformations, corresponding to a change of the space-fixed reference frame, as well as to a change of the body-fixed reference frame, which form the group M(3, 1) ext ×M(3, 1) int , and also phase transformations U(1) ch of orientational variables z. Elementary particles considered as elementary orientable objects are described by the scalar functions transforming according to irreps of the group M(3, 1) ext ×M(3, 1) int ×U(1) ch . Correspondingly, their continuous symmetries can be divided into external, which form the Poincaré group M(3, 1) ext , and internal M(3, 1) int ×U(1) ch . The assumption that the internal symmetries in the theory of orientable objects are gauge ones allows one to obtain important features of the known fundamental interactions—the electroweak and the gravitational. Localization of the group of the right translations T(4) int leads to the teleparallel theory of gravity, which is equivalent to general relativity. Localization of the compact subgroup SU(2) int ×U(1) ch leads to the theory of electroweak interactions. Thus, the suggested approach can be considered as a possible way to gravitational-electroweak unification.
Gauge field propagator and the number of fermion fields
International Nuclear Information System (INIS)
Oehme, R.; Zimmermann, W.
1980-01-01
The structure of the transverse gluon propagator D of massless quantum chromodynamics is considered in the Landau gauge. The essential differences in the weak-coupling limit g → 0 for γ 0 /β 0 >0 and γ 0 /β 0 0 and β 0 are coefficients of lowest-order terms of the anomalous dimension and of the β function. For SU(3) as the color group and quark triplets, the corresponding flavor conditions are N/sub F/ 0 /β 0 >0 there are inconsistencies with the postulates of local quantum field theory and the requirement that the positive-norm contribution D/sub +/ to D should approach its free-field value for g → 0. In the present paper, it is investigated in detail how this requirement is violated assuming that the other postulates hold, including invariance under the renormalization group. Using a specific, simple projection into a subspace of positive norm, it is shown that D/sub +/ diverges like (g 2 )/sup -gamma/0/sup /beta/0, while the free-field value and higher-order terms of D are entirely due to contributions from negative-norm states. In contradistinction, the required dominance of positive-norm states in the weak-coupling limit prevails for γ 0 /β 0 2 → 0
Gauge structure of neutral-vector field theory. [Massive vector fields, massless limits
Energy Technology Data Exchange (ETDEWEB)
Kubo, R; Yokoyama, [Hiroshima univ., Takehara (Japan). Research Inst. for Theoretical Physics
1975-03-01
General aspects of gauge structure of neutral-vector field theory are investigated from an extended standpoint, where massive vector fields are treated in a form corresponding to the electromagnetic fields in a general gauge formalism reported previously. All results obtained are shown to have unique massless limits. It is shown that a generalized q-number gauge transformation for fields makes the theory invariant in cooperation with a simultaneous transformation for relevant gauge parameters. A method of differentiation with respect to a gauge variable is found to clarify some essential features of the gauge structure. Two possible types of gauge structure also emerge correspondingly to the massless case. A neutral-vector field theory proposed in a preceding paper is included in the present framework as the most preferable case.
Multigrid Methods for the Computation of Propagators in Gauge Fields
Kalkreuter, Thomas
Multigrid methods were invented for the solution of discretized partial differential equations in order to overcome the slowness of traditional algorithms by updates on various length scales. In the present work generalizations of multigrid methods for propagators in gauge fields are investigated. Gauge fields are incorporated in algorithms in a covariant way. The kernel C of the restriction operator which averages from one grid to the next coarser grid is defined by projection on the ground-state of a local Hamiltonian. The idea behind this definition is that the appropriate notion of smoothness depends on the dynamics. The ground-state projection choice of C can be used in arbitrary dimension and for arbitrary gauge group. We discuss proper averaging operations for bosons and for staggered fermions. The kernels C can also be used in multigrid Monte Carlo simulations, and for the definition of block spins and blocked gauge fields in Monte Carlo renormalization group studies. Actual numerical computations are performed in four-dimensional SU(2) gauge fields. We prove that our proposals for block spins are “good”, using renormalization group arguments. A central result is that the multigrid method works in arbitrarily disordered gauge fields, in principle. It is proved that computations of propagators in gauge fields without critical slowing down are possible when one uses an ideal interpolation kernel. Unfortunately, the idealized algorithm is not practical, but it was important to answer questions of principle. Practical methods are able to outperform the conjugate gradient algorithm in case of bosons. The case of staggered fermions is harder. Multigrid methods give considerable speed-ups compared to conventional relaxation algorithms, but on lattices up to 184 conjugate gradient is superior.
Constant self-dual Abelian gauge fields and fermions in SU(2) gauge theory
International Nuclear Information System (INIS)
Kay, D.; Parthasarathy, R.; Viswanathan, K.S.
1983-01-01
Fermion one-loop corrections to the effective action in a self-dual Abelian background field are calculated for an SU(2) gauge theory. It is found that these corrections for massless fermions tend to destabilize the vacuum. The quantitative and qualitative features of such corrections for the case of massive fermions are discussed
Self-consistent normal ordering of gauge field theories
International Nuclear Information System (INIS)
Ruehl, W.
1987-01-01
Mean-field theories with a real action of unconstrained fields can be self-consistently normal ordered. This leads to a considerable improvement over standard mean-field theory. This concept is applied to lattice gauge theories. First an appropriate real action mean-field theory is constructed. The equations determining the Gaussian kernel necessary for self-consistent normal ordering of this mean-field theory are derived. (author). 4 refs
Non-Abelian gauge theory of fields associated with dyons
International Nuclear Information System (INIS)
Rajput, B.S.; Kumar, S.R.
1983-01-01
A suitable Lorentz invariant non-Abelian gauge theory of the fields associated with dyons has been constructed to describe the dual dynamics between colour isocharges and topological charges. It has been shown that the generalized particle current is gauge covariant and not conserved in non-Abelian theory. It has also been shown that in this theory the unphysical string variables and unphysical charged fields are not needed and that any extra constraint to maintain the dual symmetry of field equation and Lagrangian is also not needed. (author)
Dynamics of Gauge Fields at High Temperature
Nauta, B.J.
2000-01-01
An effective description of dynamical Bose fields is provided by the classical (high-temperature) limit of thermal field theory. The main subject of this thesis is to improve the ensuing classical field theory, that is, to include the dominant quantum corrections and to add counter terms for the
Non-uniqueness of the source for singular gauge fields
International Nuclear Information System (INIS)
Lanyi, G.; Pappas, R.
1977-01-01
It is shown that the singular Wu-Yang solution for SU(2) gauge fields may be interpreted as due to a point source at the origin. However, the electric or magnetic nature of the source depends on whether one approaches the singularity by means of a 'smeared' potential or a 'smeared' field strength. (Auth.)
Hotplate precipitation gauge calibrations and field measurements
Zelasko, Nicholas; Wettlaufer, Adam; Borkhuu, Bujidmaa; Burkhart, Matthew; Campbell, Leah S.; Steenburgh, W. James; Snider, Jefferson R.
2018-01-01
First introduced in 2003, approximately 70 Yankee Environmental Systems (YES) hotplate precipitation gauges have been purchased by researchers and operational meteorologists. A version of the YES hotplate is described in Rasmussen et al. (2011; R11). Presented here is testing of a newer version of the hotplate; this device is equipped with longwave and shortwave radiation sensors. Hotplate surface temperature, coefficients describing natural and forced convective sensible energy transfer, and radiative properties (longwave emissivity and shortwave reflectance) are reported for two of the new-version YES hotplates. These parameters are applied in a new algorithm and are used to derive liquid-equivalent accumulations (snowfall and rainfall), and these accumulations are compared to values derived by the internal algorithm used in the YES hotplates (hotplate-derived accumulations). In contrast with R11, the new algorithm accounts for radiative terms in a hotplate's energy budget, applies an energy conversion factor which does not differ from a theoretical energy conversion factor, and applies a surface area that is correct for the YES hotplate. Radiative effects are shown to be relatively unimportant for the precipitation events analyzed. In addition, this work documents a 10 % difference between the hotplate-derived and new-algorithm-derived accumulations. This difference seems consistent with R11's application of a hotplate surface area that deviates from the actual surface area of the YES hotplate and with R11's recommendation for an energy conversion factor that differs from that calculated using thermodynamic theory.
Gibbs perturbations of a two-dimensional gauge field
International Nuclear Information System (INIS)
Petrova, E.N.
1981-01-01
Small Gibbs perturbations of random fields have been investigated up to now for a few initial fields only. Among them there are independent fields, Gaussian fields and some others. The possibility for the investigation of Gibbs modifications of a random field depends essentially on the existence of good estimates for semiinvariants of this field. This is the reason why the class of random fields for which the investigation of Gibbs perturbations with arbitrary potential of bounded support is possible is rather small. The author takes as initial a well-known model: a two-dimensional gauge field. (Auth.)
Local gauge invariant Lagrangeans in classical field theories
International Nuclear Information System (INIS)
Grigore, D.R.
1982-07-01
We investigate the most general local gauge invariant Lagrangean in the framework of classical field theory. We rederive esentially Utiyama's result with a slight generalization. Our proof makes clear the importance of the so called current conditions, i.e. the requirement that the Noether currents are different from zero. This condition is of importance both in the general motivation for the introduction of the Yang-Mills fields and for the actual proof. Some comments are made about the basic mathematical structure of the problem - the gauge group. (author)
Lattice formulations of supersymmetric gauge theories with matter fields
International Nuclear Information System (INIS)
Joseph, Anosh
2014-12-01
Certain classes of supersymmetric gauge theories, including the well known N=4 supersymmetric Yang-Mills theory, that takes part in the AdS/CFT correspondence, can be formulated on a Euclidean spacetime lattice using the techniques of exact lattice supersymmetry. Great ideas such as topological field theories, Dirac-Kaehler fermions, geometric discretization all come together to create supersymmetric lattice theories that are gauge-invariant, doubler free, local and exact supersymmetric. We discuss the recent lattice constructions of supersymmetric Yang-Mills theories in two and three dimensions coupled to matter fields in various representations of the color group.
Gauge-independent decoherence models for solids in external fields
Wismer, Michael S.; Yakovlev, Vladislav S.
2018-04-01
We demonstrate gauge-invariant modeling of an open system of electrons in a periodic potential interacting with an optical field. For this purpose, we adapt the covariant derivative to the case of mixed states and put forward a decoherence model that has simple analytical forms in the length and velocity gauges. We demonstrate our methods by calculating harmonic spectra in the strong-field regime and numerically verifying the equivalence of the deterministic master equation to the stochastic Monte Carlo wave-function method.
Wormholes, emergent gauge fields, and the weak gravity conjecture
Energy Technology Data Exchange (ETDEWEB)
Harlow, Daniel [Center for the Fundamental Laws of Nature, Physics Department, Harvard University,Cambridge MA, 02138 (United States)
2016-01-20
This paper revisits the question of reconstructing bulk gauge fields as boundary operators in AdS/CFT. In the presence of the wormhole dual to the thermofield double state of two CFTs, the existence of bulk gauge fields is in some tension with the microscopic tensor factorization of the Hilbert space. I explain how this tension can be resolved by splitting the gauge field into charged constituents, and I argue that this leads to a new argument for the “principle of completeness”, which states that the charge lattice of a gauge theory coupled to gravity must be fully populated. I also claim that it leads to a new motivation for (and a clarification of) the “weak gravity conjecture”, which I interpret as a strengthening of this principle. This setup gives a simple example of a situation where describing low-energy bulk physics in CFT language requires knowledge of high-energy bulk physics. This contradicts to some extent the notion of “effective conformal field theory”, but in fact is an expected feature of the resolution of the black hole information problem. An analogous factorization issue exists also for the gravitational field, and I comment on several of its implications for reconstructing black hole interiors and the emergence of spacetime more generally.
Non-Abelian tensor gauge fields and higher-spin extension of standard model
International Nuclear Information System (INIS)
Savvidy, G.
2006-01-01
We suggest an extension of the gauge principle which includes non-Abelian tensor gauge fields. The invariant Lagrangian is quadratic in the field strength tensors and describes interaction of charged tensor gauge bosons of arbitrary large integer spin 1,2,l. Non-Abelian tensor gauge fields can be viewed as a unique gauge field with values in the infinite-dimensional current algebra associated with compact Lie group. The full Lagrangian exhibits also enhanced local gauge invariance with double number of gauge parameters which allows to eliminate all negative norm states of the nonsymmetric second-rank tensor gauge field, which describes therefore two polarizations of helicity-two massless charged tensor gauge boson and the helicity-zero ''axion'' The geometrical interpretation of the enhanced gauge symmetry with double number of gauge parameters is not yet known. (Abstract Copyright [2006], Wiley Periodicals, Inc.)
Determining and uniformly estimating the gauge potential corresponding to a given gauge field on M4
International Nuclear Information System (INIS)
Mostow, M.; Shnider, S.; Ben-Gurion Univ. of the Negev, Beersheba
1986-01-01
In an earlier paper on the field copy problem, we proved that there exists a generic set of connections (gauge potentials) on a principle bundle with a semi-simple structure group over a four-dimensional base manifold for which the connection is uniquely determined by its curvature (gauge field). We conjectured that there exists a smaller, but still generic, set of connections for which the curvature map sending a connection to its curvature admits a continuous inverse with respect to the appropriate function space topologies. The conjecture says, in other words, that restricting to certain generic curvature 2-forms, one can determine and uniformly estimate the connection and its derivatives from the curvature and uniform estimates of its derivatives. In this Letter we give an affirmative answer to the conjecture and show, moreover, that the set of such connections contains an open dense set in the Whitney C ∞ topology. (orig.)
Gauge-invariant charged, monopole and dyon fields in gauge theories
International Nuclear Information System (INIS)
Froehlich, J.; Marchetti, P.A.
1999-01-01
We propose explicit recipes to construct the Euclidean Green functions of gauge-invariant charged, monopole and dyon fields in four-dimensional gauge theories whose phase diagram contains phases with deconfined electric and/or magnetic charges. In theories with only either abelian electric or magnetic charges, our construction is an Euclidean version of Dirac's original proposal, the magnetic dual of his proposal, respectively. Rigorous mathematical control is achieved for a class of abelian lattice theories. In theories where electric and magnetic charges coexist, our construction of Green functions of electrically or magnetically charged fields involves taking an average over Mandelstam strings or the dual magnetic flux tubes, in accordance with Dirac's flux quantization condition. We apply our construction to 't Hooft-Polyakov monopoles and Julia-Zee dyons. Connections between our construction and the semiclassical approach are discussed
Gauge field theories on a || lattice
International Nuclear Information System (INIS)
Burkardt, Matthias
1999-01-01
In these notes, the transverse || lattice approach is presented as a means to control the k + →0 divergences in light-front QCD. Technical difficulties of both the canonical compact formulation as well as the non-compact formulation of the || lattice motivate the color-dielectric formulation, where the link fields are linearized
Operation of cold-cathode gauges in high magnetic fields
International Nuclear Information System (INIS)
Thomas, S.R. Jr.; Goerz, D.A.; Pickles, W.L.
1985-01-01
The Mirror Fusion Test Facility (MFTF-B), under construction at LLNL, requires measurement of the neutral gas density in high magnetic fields near the plasma at several axial regions. This Background Gas Pressure (BGP) diagnostic will help us understand the role of background neutrals in particle and power balance, particularly in the maintenance of the cold halo plasma that shields the hot core plasma from the returning neutrals. It consists of several cold-cathode, magnetron-type gauges stripped of their permanent magnets, and utilizes the MFTF-B ambient B-field in strengths of 5 to 25 kG. Similar gauges have operated in TMX-U in B-fields up to 3 kG. To determine how well the gauges will perform, we assembled a test stand which operated magnetron gauges in an external, uniform magnetic field of up to 30 kG, over a pressure range of 1E-8 T to 1E-5 T, at several cathode voltages. This paper describes the test stand and presents the results of the tests
Gauge field back reaction on a black hole
International Nuclear Information System (INIS)
Hochberg, D.; Kephart, T.W.
1993-01-01
The order-ℎ fluctuations of gauge fields in the vicinity of a black hole can create a repulsive antigravity region extending out beyond the renormalized Schwarzschild horizon. If the strength of this repulsive force increases as higher orders in the back reaction are included, the formation of a wormholelike object could occur
Gauge field governing parallel transport along mixed states
International Nuclear Information System (INIS)
Uhlmann, A.
1990-01-01
At first a short account is given of some basic notations and results on parallel transport along mixed states. A new connection form (gauge field) is introduced to give a geometric meaning to the concept of parallelity in the theory of density operators. (Author) 11 refs
On classical solutions of SU(3) gauge field equations
International Nuclear Information System (INIS)
Chakrabarti, A.
1975-01-01
Static classical solutions of SU(3) gauge field equations are studied. The roles of the O(3) subgroup and of the quadrupole generators are discussed systematically. The general form thus obtained leads, through-out, to a high degree of symmetry in the results. This brings in some simplifying features. An octet of scalar mesons is finally added. Certain classes of exact solutions are given that are singular at the origin. A generalized gauge condition is pointed out. The relation of the general form to known particular cases is discussed [fr
Interplay between topology, gauge fields and gravity
Corichi Rodriguez Gil, Alejandro
In this thesis we consider several physical systems that illustrate an interesting interplay between quantum theory, connections and knot theory. It can be divided into two parts. In the first one, we consider the quantization of the free Maxwell field. We show that there is an important role played by knot theory, and in particular the Gauss linking number, in the quantum theory. This manifestation is twofold. The first occurs at the level of the algebra of observables given by fluxes of electric and magnetic field across surfaces. The commutator of the operators, and thus the basic uncertainty relations, are given in terms of the linking number of the loops that bound the surfaces. Next, we consider the quantization of the Maxwell field based on self-dual connections in the loop representation. We show that the measure which determines the quantum inner product can be expressed in terms of the self linking number of thickened loops. Therefore, the linking number manifests itself at two key points of the theory: the Heisenberg uncertainty principle and the inner product. In the second part, we bring gravity into play. First we consider quantum test particles on certain stationary space-times. We demonstrate that a geometric phase exists for those space-times and focus on the example of a rotating cosmic string. The geometric phase can be explicitly computed, providing a fully relativistic gravitational Aharonov-Bohm effect. Finally, we consider 3-dimensional gravity with non-vanishing cosmological constant in the connection dynamics formulation. We restrict our attention to Lorentzian gravity with positive cosmological constant and Euclidean signature with negative cosmological constant. A complex transformation is performed in phase space that makes the constraints simple. The reduced phase space is characterized as the moduli space of flat complex connections. We construct the quantization of the theory when the initial hyper-surface is a torus. Two important
A Unified Field Theory of Gravity, Electromagnetism, and the Yang-Mills Gauge Field
Directory of Open Access Journals (Sweden)
Suhendro I.
2008-01-01
Full Text Available In this work, we attempt at constructing a comprehensive four-dimensional unified field theory of gravity, electromagnetism, and the non-Abelian Yang-Mills gauge field in which the gravitational, electromagnetic, and material spin fields are unified as intrinsic geometric objects of the space-time manifold S4 via the connection, with the general- ized non-Abelian Yang-Mills gauge field appearing in particular as a sub-field of the geometrized electromagnetic interaction.
Ballu, V.; Bouin, M.; Baillard, C.; Calmant, S.; Pelletier, B.; Crawford, W. C.; Kanas, T.; Garaebiti, E.
2012-12-01
two offshore sites using absolute pressure gauges. The sites - Wusi and Sabine Banks - are installed beneath altimetry satellite tracks, Wusi Bank on the over-riding plate and Sabine Bank on the subducting plate. The difference in the pressure records between the sites shows that Wusi Bank subsides by 11 +/- 3 mm/yr with respect to Sabine Bank. We combined the water depths derived from the pressure measurements with altimetry-derived sea-surface heights to tie these heights to a global reference frame: Wusi Bank subsides and Sabine Bank's vertical motion is near zero. Using a 2D elastic model and a finite-element code, we used the gradient of vertical deformation between the coast and the Wusi Bank site to discriminate between possible locked zone geometries. The best simple approximation is a 25° dipping, 30 km long fully locked zone, indicating that stress is currently accumulating west of Santo, Central Vanuatu. The movement of Wusi Bank is a key factor in constraining the dip and length of the locked zone, demonstrating the importance of offshore geodesy measurements.
Measurement of gravity and gauge fields using quantum mechanical probes
International Nuclear Information System (INIS)
Anandan, J.
1986-01-01
The author considers the question of which quantities are observed when the gravitational and gauge fields are measured by a quantum mechanical probe. The motion of a quantum mechanical particle can be constructed, via Huyghens' principle, by the interference of secondary wavelets. Three types of interference phenomena are considered: interference of two coherent beams separated in space-time during part of their motion; interference of two coherent beams which are in the same region in spacetime but differ in energy or mass; and the Josphson effect and its generalization. The author shows how to determine the gravitational field by means of quantum interference. The corresponding problem for gauge fields is treated and a simple proof of the previously proved theorem for the reconstruction of the connection from the holonomy transformations is presented. A heuristic principle for the gravitational interaction of two quantum mechanical particles is formulated which implies the equivalence of inertial and active gravitational masses
Strong coupling in a gauge invariant field theory
Energy Technology Data Exchange (ETDEWEB)
Johnson, K. [Physics Department, Massachusetts Institute of Technology, Cambridge, MA (United States)
1963-01-15
I would like to discuss some approximations which may be significant in the domain of strong coupling in a field system analogous to quantum electrodynamics. The motivation of this work is the idea that the strong couplings and elementary particle spectrum may be the consequence of the dynamics of a system whose underlying description is in terms of a set of Fermi fields gauge invariantly coupled to a single (''bare'') massless neutral vector field. The basis of this gauge invariance would of course be the exact conservation law of baryons or ''nucleonic charge''. It seems to me that a coupling scheme based on an invariance principle is most attractive if that invariance is an exact one. It would then be nice to try to account for the approximate invariance principles in the same way one would describe ''accidental degeneracies'' in any quantum system.
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.
A gauge quantum field theory of confined quarks and gluons
International Nuclear Information System (INIS)
Voelkel, A.H.
1983-01-01
A SU(3)-gauge quantum field theory with a quark triplet, an antiquark triplet and a self-conjugate gluon octet as basic fields is investigated. In virtue of a non trivial coupling between the representation of the translation group and the SU(3)-colour charge of the basic fields it is proved: (i) The basic quark, antiquark and gluon fields are confined. (ii) Every statevector of the physical Hilbert space is a SU(3)-colour singlet state. (iii) Poincare invariance holds in the physical Hilbert space. (orig.)
Enhanced gauge symmetry and winding modes in double field theory
Energy Technology Data Exchange (ETDEWEB)
Aldazabal, G. [Centro Atómico Bariloche,8400 S.C. de Bariloche (Argentina); Instituto Balseiro (CNEA-UNC) and CONICET,8400 S.C. de Bariloche (Argentina); Graña, M. [Institut de Physique Théorique, CEA/ Saclay,91191 Gif-sur-Yvette Cedex (France); Iguri, S. [Instituto de Astronomía y Física del Espacio (CONICET-UBA), Universidad de Buenos Aires,1428 Buenos Aires (Argentina); Mayo, M. [Centro Atómico Bariloche,8400 S.C. de Bariloche (Argentina); Instituto Balseiro (CNEA-UNC) and CONICET,8400 S.C. de Bariloche (Argentina); Nuñez, C. [Instituto de Astronomía y Física del Espacio (CONICET-UBA), Universidad de Buenos Aires,1428 Buenos Aires (Argentina); Departamento de Física, FCEN, Universidad de Buenos Aires,C.C. 67 - Suc. 28, 1428 Buenos Aires (Argentina); Rosabal, J.A. [Departamento de Física, FCEN, Universidad de Buenos Aires,C.C. 67 - Suc. 28, 1428 Buenos Aires (Argentina)
2016-03-15
We provide an explicit example of how the string winding modes can be incorporated in double field theory. Our guiding case is the closed bosonic string compactified on a circle of radius close to the self-dual point, where some modes with non-zero winding or discrete momentum number become massless and enhance the U(1)×U(1) symmetry to SU(2)×SU(2). We compute three-point string scattering amplitudes of massless and slightly massive states, and extract the corresponding effective low energy gauge field theory. The enhanced gauge symmetry at the self-dual point and the Higgs-like mechanism arising when changing the compactification radius are examined in detail. The extra massless fields associated to the enhancement are incorporated into a generalized frame with ((O(d+3,d+3))/(O(d+3)×O(d+3))) structure, where d is the number of non-compact dimensions. We devise a consistent double field theory action that reproduces the low energy string effective action with enhanced gauge symmetry. The construction requires a truly non-geometric frame which explicitly depends on both the compact coordinate along the circle and its dual.
Polarization-dependent optics using gauge-field metamaterials
International Nuclear Information System (INIS)
Liu, Fu; Xiao, Shiyi; Li, Jensen; Wang, Saisai; Hang, Zhi Hong
2015-01-01
We show that effective gauge field for photons with polarization-split dispersion surfaces, being realized using uniaxial metamaterials, can be used for polarization control with unique opportunities. The metamaterials with the proposed gauge field correspond to a special choice of eigenpolarizations on the Poincaré sphere as pseudo-spins, in contrary to those from either conventional birefringent crystals or optical active media. It gives rise to all-angle polarization control and a generic route to manipulate photon trajectories or polarizations in the pseudo-spin domain. As demonstrations, we show beam splitting (birefringent polarizer), all-angle polarization control, unidirectional polarization filter, and interferometer as various polarization control devices in the pseudo-spin domain. We expect that more polarization-dependent devices can be designed under the same framework
Symmetry breaking by Wilson loops in gauge field theory
International Nuclear Information System (INIS)
Dowker, J.S.; Jadhav, S.P.
1989-01-01
An analysis is presented of the gauge symmetry breaking caused by Wilson loops on a space-time whose spatial section is openR/sup d/ x S 3 /Γ, for all those fundamental groups Γ that give a homogeneous space. We concentrate on pure SU(3) and SU(5) gauge field theories and find that symmetry breaking can occur when d = 0, for all Γ. If d = 3, the extra minimal scalars prevent any breaking and one must include other fields to achieve this. Explicit forms for the vacuum energies are exhibited in the case of lens and prism spaces, the former for SU(n). For Γ = Z/sub m/, when m and the radius of the sphere become infinite, we recover the results on the space-time openR/sup d//sup +3/ x S 1
Light cone sum rules in nonabelian gauge field theory
Energy Technology Data Exchange (ETDEWEB)
Mallik, S [Bern Univ. (Switzerland). Inst. fuer Theoretische Physik
1981-03-24
The author examines, in the context of nonabelian gauge field theory, the derivation of the light cone sum rules which were obtained earlier on the assumption of dominance of canonical singularity in the current commutator on the light cone. The retarded scaling functions appearing in the sum rules are numbers known in terms of the charges of the quarks and the number of quarks and gluons in the theory. Possible applications of the sum rules are suggested.
Gauge field geometry from complex and harmonic analyticities
International Nuclear Information System (INIS)
Gal'perin, A.S.; Ivanov, E.A.; Ogievetsky, V.I.; Sokatchev, E.
1987-01-01
The analyticity preservation principle is employed to demonstrate and impressive affinity between field theories with intrinsic analytic structure and superfield gauge theories. The defining constraints of the former theories are interpreted as the integrability conditions for the existence of appropriate analytic subspaces and are solved by passing to the basis with manifest analyticity. We prefer to work within the analytic basis. This allows, e.g., to replace the nonlinear splitting problem of twistor approach by solving a linear equation
The Weyl non-Abelian gauge field and the Thomas precession
International Nuclear Information System (INIS)
Barbashov, B.M.; Pestov, A.B.
1998-01-01
The connection between the Fermi-Walker transport and the Weyl non-Abelian gauge field is established. A theoretical possibility of detecting the Weyl gauge field caused by the Thomas precession of a gyroscope is discussed
Representations of l-p-i functionals in gauge field theories
International Nuclear Information System (INIS)
Bordag, M.; Kaschluhn, L.; Matveev, V.A.; Robaschik, D.
1981-01-01
A representation of the functions which solve by construction the Slavnov-Taylor identities and contain independent coefficient functions is given. These solutions show the different role of the gauge field which acts in some respect as an ordinary field. The Slavnov-Taylor identities are solved for axial gauge conditions in non-Abelian gauge field theory and in quantum electrodynamics
Modulation of the waterfall by a gauge field
International Nuclear Information System (INIS)
Lyth, David H.; Karčiauskas, Mindaugas
2013-01-01
We present the first complete calculation of the curvature perturbation generated during the hybrid inflation waterfall, caused by the coupling of the waterfall field to a gauge field A whose kinetic function f 2 depends on the inflaton field. We impose an upper bound on the field A≡fA which ensures that it has a negligible effect before the waterfall. We confirm the claim of Soda and Yokoyama, that the perturbation δB generates a statistically anisotropic spectrum and bispectrum, which could easily be observable. We also discover a new phenomenon, whereby the time-dependent 'varyon' field B causes the inflaton contribution to vary during the waterfall. The varyon mechanism might be implemented also with a scalar field and might not involve the waterfall
Globally conformal invariant gauge field theory with rational correlation functions
Nikolov, N M; Todorov, I T; CERN. Geneva; Todorov, Ivan T.
2003-01-01
Operator product expansions (OPE) for the product of a scalar field with its conjugate are presented as infinite sums of bilocal fields $V_{\\kappa} (x_1, x_2)$ of dimension $(\\kappa, \\kappa)$. For a {\\it globally conformal invariant} (GCI) theory we write down the OPE of $V_{\\kappa}$ into a series of {\\it twist} (dimension minus rank) $2\\kappa$ symmetric traceless tensor fields with coefficients computed from the (rational) 4-point function of the scalar field. We argue that the theory of a GCI hermitian scalar field ${\\cal L} (x)$ of dimension 4 in $D = 4$ Minkowski space such that the 3-point functions of a pair of ${\\cal L}$'s and a scalar field of dimension 2 or 4 vanish can be interpreted as the theory of local observables of a conformally invariant fixed point in a gauge theory with Lagrangian density ${\\cal L} (x)$.
Strings - Links between conformal field theory, gauge theory and gravity
International Nuclear Information System (INIS)
Troost, J.
2009-05-01
String theory is a candidate framework for unifying the gauge theories of interacting elementary particles with a quantum theory of gravity. The last years we have made considerable progress in understanding non-perturbative aspects of string theory, and in bringing string theory closer to experiment, via the search for the Standard Model within string theory, but also via phenomenological models inspired by the physics of strings. Despite these advances, many deep problems remain, amongst which a non-perturbative definition of string theory, a better understanding of holography, and the cosmological constant problem. My research has concentrated on various theoretical aspects of quantum theories of gravity, including holography, black holes physics and cosmology. In this Habilitation thesis I have laid bare many more links between conformal field theory, gauge theory and gravity. Most contributions were motivated by string theory, like the analysis of supersymmetry preserving states in compactified gauge theories and their relation to affine algebras, time-dependent aspects of the holographic map between quantum gravity in anti-de-Sitter space and conformal field theories in the bulk, the direct quantization of strings on black hole backgrounds, the embedding of the no-boundary proposal for a wave-function of the universe in string theory, a non-rational Verlinde formula and the construction of non-geometric solutions to supergravity
Supersymmetric gauge theories, quantization of Mflat, and conformal field theory
International Nuclear Information System (INIS)
Teschner, J.; Vartanov, G.S.
2013-02-01
We propose a derivation of the correspondence between certain gauge theories with N=2 supersymmetry and conformal field theory discovered by Alday, Gaiotto and Tachikawa in the spirit of Seiberg-Witten theory. Based on certain results from the literature we argue that the quantum theory of the moduli spaces of flat SL(2,R)-connections represents a nonperturbative ''skeleton'' of the gauge theory, protected by supersymmetry. It follows that instanton partition functions can be characterized as solutions to a Riemann-Hilbert type problem. In order to solve it, we describe the quantization of the moduli spaces of flat connections explicitly in terms of two natural sets of Darboux coordinates. The kernel describing the relation between the two pictures represents the solution to the Riemann Hilbert problem, and is naturally identified with the Liouville conformal blocks.
Extended BRST symmetries in the gauge field theory
International Nuclear Information System (INIS)
Babalean, Aurel; Constantinescu, Radu; Ionescu, Carmen
2001-01-01
The BRST procedure provides one of the most powerful methods for the quantum description of the gauge field theories. As already stated, the unphysical degrees of freedom that appear in this case can be easily canceled by the introduction of the ghost type variables. In the Hamiltonian formalism, the structure of the ghost that must be used mainly depends on two factors: - the type of the theory, that this the relations among the constraints of the theory; - the extension of the symmetry to be implemented. The paper presents the structure of the extended phase space suitable for the BRST canonical quantization of a 1- reducible gauge theory in the frame of a BRST symmetry of order three. The corresponding BRST charges and the extended Hamiltonian are also constructed. (authors)
Group quantization on configuration space: Gauge symmetries and linear fields
International Nuclear Information System (INIS)
Navarro, M.; Aldaya, V.; Calixto, M.
1997-01-01
A new, configuration-space picture of a formalism of group quantization, the GAQ formalism, is presented in the context of a previous algebraic generalization. This presentation serves to make a comprehensive discussion in which other extensions of the formalism, principally to incorporate gauge symmetries, are developed as well. Both images are combined in order to analyze, in a systematic manner and with complete generality, the case of linear fields (Abelian current groups). To illustrate these developments we particularize them for several fields and, in particular, we carry out the quantization of the Abelian Chern endash Simons models over an arbitrary closed surface in detail. copyright 1997 American Institute of Physics
New results in topological field theory and Abelian gauge theory
International Nuclear Information System (INIS)
Thompson, G.
1995-10-01
These are the lecture notes of a set of lectures delivered at the 1995 Trieste summer school in June. I review some recent work on duality in four dimensional Maxwell theory on arbitrary four manifolds, as well as a new set of topological invariants known as the Seiberg-Witten invariants. Much of the necessary background material is given, including a crash course in topological field theory, cohomology of manifolds, topological gauge theory and the rudiments of four manifold theory. My main hope is to wet the readers appetite, so that he or she will wish to read the original works and perhaps to enter this field. (author). 41 refs, 5 figs
New results in topological field theory and Abelian gauge theory
Energy Technology Data Exchange (ETDEWEB)
Thompson, G
1995-10-01
These are the lecture notes of a set of lectures delivered at the 1995 Trieste summer school in June. I review some recent work on duality in four dimensional Maxwell theory on arbitrary four manifolds, as well as a new set of topological invariants known as the Seiberg-Witten invariants. Much of the necessary background material is given, including a crash course in topological field theory, cohomology of manifolds, topological gauge theory and the rudiments of four manifold theory. My main hope is to wet the readers appetite, so that he or she will wish to read the original works and perhaps to enter this field. (author). 41 refs, 5 figs.
International Nuclear Information System (INIS)
Nakawaki, Yuji; McCartor, Gary
2006-01-01
We construct a new perturbative formulation of pure space-like axial gauge QED in which the inherent infrared divergences are regularized by residual gauge fields. For this purpose, we carry out our calculations in the coordinates x μ =(x + , x - , x 1 , x 2 ), where x + =x 0 sinθ + x 3 cosθ and x - = x 0 cosθ - x 3 sinθ. Here, A=A 0 cosθ + A 3 sinθ = n·A=0 is taken as the gauge fixing condition. We show in detail that, in perturbation theory, infrared divergences resulting from the residual gauge fields cancel infrared divergences resulting from the physical parts of the gauge field. As a result, we obtain the gauge field propagator proposed by Mandelstam and Leibbrandt. By taking the limit θ→π/4, we are able to construct a light-cone formulation that is free from infrared divergences. With that analysis complete, we next calculate the one-loop electron self-energy, something not previously done in the light-cone quantization and light-cone gauge. (author)
Questions of quark confinement and ambiguities in Coulomb gauge of Yang-Mills fields
International Nuclear Information System (INIS)
Abarbanel, H.D.I.; Bartels, J.
1978-01-01
The ambiguities considered by Gribov in the formulation of Coulomb gauge in non-Abelian gauge theories are discussed and the division of gauge field space into a sector with a unique transverse gauge, a sector with a two-fold ambiguity in transverse gauge, etc. is reviewed. The authors argue in a semi-classical fashion that transitions between these sectors readily occur and discuss the connection with ideas of quark confinement in Coulomb gauge. Because of these transitions it appears that the functional integral formulation of Coulomb gauge will be rather more complicated than expected in the past. (Auth.)
Gravitational waves in bouncing cosmologies from gauge field production
Energy Technology Data Exchange (ETDEWEB)
Ben-Dayan, Ido, E-mail: ido.bendayan@gmail.com [Department of Physics, Ben-Gurion University of the Negev, P.O. Box 653, Be' er-Sheva 8410500 (Israel)
2016-09-01
We calculate the gravitational waves (GW) spectrum produced in various Early Universe scenarios from gauge field sources, thus generalizing earlier inflationary calculations to bouncing cosmologies. We consider generic couplings between the gauge fields and the scalar field dominating the energy density of the Universe. We analyze the requirements needed to avoid a backreaction that will spoil the background evolution. When the scalar is coupled only to F F-tilde term, the sourced GW spectrum is exponentially enhanced and parametrically the square of the vacuum fluctuations spectrum, P {sup s} {sub T} ∼ (P {sup v} {sub T} ){sup 2}, giving an even bluer spectrum than the standard vacuum one. When the scalar field is also coupled to F {sup 2} term, the amplitude is still exponentially enhanced, but the spectrum can be arbitrarily close to scale invariant (still slightly blue), n {sub T} ∼> 0, that is distinguishable form the slightly red inflationary one. Hence, we have a proof of concept of observable GW on CMB scales in a bouncing cosmology.
Response of SU(2) lattice gauge theory to a gauge invariant external field
International Nuclear Information System (INIS)
Goepfert, M.
1980-10-01
Topologically determined Z(2) variables in pure SU(2) lattice gauge theory are discussed. They count the number of 'vortex souls'. The expectation value of the corresponding Z(2) loop and the dependence of the string tension on an external field h coupled to them is calculated to lowest order in the high temperature expansion. The result is in agreement with the conjecture that the probability distribution of vortex souls determines the string tension. A different formula for the string tension is found in the two limiting cases 0 < /h/ << β << 1 and 0 < β << h << 1. This penomenon is traced to the effect of short range interactions of the vortex souls which are mediated by the other excitations in the theory. (orig.)
A multiscale view of propagators in gauge fields
Energy Technology Data Exchange (ETDEWEB)
Baeker, M
1995-07-01
The Iteratively Smoothing Unigrid (ISU) is presented and studied in detail. An appropriate definition of smoothness in the presence of disordered gauge fields is given on which the algorith is based. ISU uses an iterative process to determ is based. ISU uses an iterative process to determine the interpolation operators as the eigenvectors to the lowest eigenvalues on blocks of larger and larger sizes. We always used the algorith in two dim in two dimensions, usually with SU(2) gauge fields. The ISU algorith perform performs extreely well for the case of the covariant Laplace equation with arbitrarily large disorder. For the Dirac equation, critical slowing down is elimely well for the case of the covariant Laplace equation with arbitrarily large disorder. For the Dirac equation, critical slowing down is eliminated in the continuu lim limit, but when {beta} is kept fixed and the lattice size is increased the critical exponent is estiated to z{approx}1.6. (orig.) methods prove that the problem is due to the many eigenmodes of the Dirac operator that have low eigenvalues and can not be approximated well by the used localized interpolation operators. That the Laplace equation is solved efficiently is caused by the phenomenon of Localization: The lowest modes of the Laplace operator are strongly localized when the disorder of the gauge field is large. We also present an explanation of this phenomenon. For the Dirac operator in two dimension, no localization is found; the reasons for this are not known. It is explained in detail why localization helps to improve the convergence of the algorithm. After having analyzed the problems of the algorithm for the Dirac equation, we try to invent a cure. It consists of two parts: We change the shapes of the supports of the interpolation operators and we introduce the possibility of having more than one interpolation operators per block-lattice point. (Abstract Truncated)
Role of gauge invariance in a variational and mean-field calculation
International Nuclear Information System (INIS)
Masperi, L.; Omero, C.
1981-08-01
We show that the implementation of gauge invariance is essential for a variational treatment to correctly reproduce all the features of the phase diagram for the Z(2) lattice gauge theory with matter field. (author)
Classical and quantum mechanics of non-abelian gauge fields
International Nuclear Information System (INIS)
Savvidy, G.K.
1984-01-01
Classical and quantum mechanics of non-abelian gauge fields are investigated both with and without spontaneous symmetry breaking. The fundamental subsystem (FS) of Yang-Mills classical mechanics (YMCM) is considered. It is shown to be a Kolmogorov K-system, and hence to have strong statistical properties. Integrable systems are also found, to which in terms of KAM theory Yang-Mills-Higgs classical mechanics (YMHCM) is close. Quantum-mechanical properties of the YM system and their relation to the problem of confinement are discussed. (orig.)
Effective Einsteinian gravity from Poincare gauge field theory
International Nuclear Information System (INIS)
Baekler, P.; Mielke, E.W.
1985-10-01
The Poincare gauge theory of gravity should apply in the microphysical domain. Here we investigate its implications for macrophysics. Weakly self double dual Riemann-Cartan curvature is assumed throughout. It is shown that the metrical background is then determined by Einstein's field equations with the Belinfante-Rosenfeld symmetrized energy-momentum current amended by spin squared terms. Moreover, the effective cosmological constant can be reconciled with the empirical data by absorbing the corresponding constant curvature part into the dynamical torsion of recently found exact solutions. Macroscopically this extra torsion remains undetectable. (author)
Constrained variational calculus for higher order classical field theories
Energy Technology Data Exchange (ETDEWEB)
Campos, Cedric M; De Leon, Manuel; De Diego, David MartIn, E-mail: cedricmc@icmat.e, E-mail: mdeleon@icmat.e, E-mail: david.martin@icmat.e [Instituto de Ciencias Matematicas, CSIC-UAM-UC3M-UCM, Serrano 123, 28006 Madrid (Spain)
2010-11-12
We develop an intrinsic geometrical setting for higher order constrained field theories. As a main tool we use an appropriate generalization of the classical Skinner-Rusk formalism. Some examples of applications are studied, in particular to the geometrical description of optimal control theory for partial differential equations.
Constrained variational calculus for higher order classical field theories
International Nuclear Information System (INIS)
Campos, Cedric M; De Leon, Manuel; De Diego, David MartIn
2010-01-01
We develop an intrinsic geometrical setting for higher order constrained field theories. As a main tool we use an appropriate generalization of the classical Skinner-Rusk formalism. Some examples of applications are studied, in particular to the geometrical description of optimal control theory for partial differential equations.
Body fixed frame, rigid gauge rotations and large N random fields in QCD
International Nuclear Information System (INIS)
Levit, S.
1995-01-01
The ''body fixed frame'' with respect to local gauge transformations is introduced. Rigid gauge ''rotations'' in QCD and their Schroedinger equation are studied for static and dynamic quarks. Possible choices of the rigid gauge field configuration corresponding to a non-vanishing static colormagnetic field in the ''body fixed'' frame are discussed. A gauge invariant variational equation is derived in this frame. For large number N of colors the rigid gauge field configuration is regarded as random with maximally random probability distribution under constraints on macroscopic-like quantities. For the uniform magnetic field the joint probability distribution of the field components is determined by maximizing the appropriate entropy under the area law constraint for the Wilson loop. In the quark sector the gauge invariance requires the rigid gauge field configuration to appear not only as a background but also as inducing an instantaneous quark-quark interaction. Both are random in the large N limit. (orig.)
Mean fields and self consistent normal ordering of lattice spin and gauge field theories
International Nuclear Information System (INIS)
Ruehl, W.
1986-01-01
Classical Heisenberg spin models on lattices possess mean field theories that are well defined real field theories on finite lattices. These mean field theories can be self consistently normal ordered. This leads to a considerable improvement over standard mean field theory. This concept is carried over to lattice gauge theories. We construct first an appropriate real mean field theory. The equations determining the Gaussian kernel necessary for self-consistent normal ordering of this mean field theory are derived. (orig.)
From topological quantum field theories to supersymmetric gauge theories
International Nuclear Information System (INIS)
Bossard, G.
2007-10-01
This thesis contains 2 parts based on scientific contributions that have led to 2 series of publications. The first one concerns the introduction of vector symmetry in cohomological theories, through a generalization of the so-called Baulieu-Singer equation. Together with the topological BRST (Becchi-Rouet-Stora-Tyutin) operator, this symmetry gives an off-shell closed sub-sector of supersymmetry that permits to determine the action uniquely. The second part proposes a methodology for re-normalizing supersymmetric Yang-Mills theory without assuming a regularization scheme which is both supersymmetry and gauge invariance preserving. The renormalization prescription is derived thanks to the definition of 2 consistent Slavnov-Taylor operators for supersymmetry and gauge invariance, whose construction requires the introduction of the so-called shadow fields. We demonstrate the renormalizability of supersymmetric Yang-Mills theories. We give a fully consistent, regularization scheme independent, proof of the vanishing of the β function and of the anomalous dimensions of the one half BPS operators in maximally supersymmetric Yang-Mills theory. After a short introduction, in chapter two, we give a review of the cohomological Yang-Mills theory in eight dimensions. We then study its dimensional reductions in seven and six dimensions. The last chapter gives quite independent results, about a geometrical interpretation of the shadow fields, an unpublished work about topological gravity in four dimensions, an extension of the shadow formalism to superconformal invariance, and finally the solution of the constraints in a twisted superspace. (author)
Massive Higher Dimensional Gauge Fields as Messengers of Supersymmetry Breaking
International Nuclear Information System (INIS)
Chacko, Z.; Luty, Markus A.; Ponton, Eduardo
2000-01-01
We consider theories with one or more compact dimensions with size r > 1/M, where M is the fundamental Planck scale, with the visible and hidden sectors localized on spatially separated 3 -branes''. We show that a bulk U(1) gauge field spontaneously broken on the hidden-sector 3-brane is an attractive candidate for the messenger of supersymmetry breaking. In this scenario scalar mass-squared terms are proportional to U(1) charges, and therefore naturally conserve flavor. Arbitrary flavor violation at the Planck scale gives rise to exponentially suppressed flavor violation at low energies. Gaugino masses can be generated if the standard gauge fields propagate in the bulk; μ and Bμ terms can be generated by the Giudice-Masiero or by the VEV of a singlet in the visible sector. The latter case naturally solves the SUSY CP problem. Realistic phenomenology can be obtained either if all microscopic parameters are order one in units of M, or if the theory is strongly coupled at the scale M. (For the latter case, we estimate parameters by extending n aive dimensional analysis'' to higher-dimension theories with branes.) In either case, the only unexplained hierarchy is the l arge'' size of the extra dimensions in fundamental units, which need only be an order of magnitude. All soft masses are naturally within an order of magnitude of m 3/2 , and trilinear scalar couplings are negligible. Squark and slepton masses can naturally unify even in the absence of grand unification. (author)
Hidden singularities in non-abelian gauge fields
International Nuclear Information System (INIS)
Bollini, C.G.; Giambiagi, J.J.; Tiomno, J.
1978-01-01
It is shown that the potential (and field) of a non-abelian gauge theory is not well determined when it has a singular point. When this is the cause, it is important to specify the regularization procedure used to give a precise definition of physical quantities at the singularity at any stage of the computation. The fact that a certain A sub(μ) (associated with the given regularization) represents the vacuum when F sub(μν) is a zero distribution not only on the global space but also in all its projections to arbitrary subspaces is discussed. The example used as a base for the discussion is A vetor = i (sigma vetor Λ r vetor / r 2 ). For this example it is shown that different regularizations give the same field in the global space but they give different distributions when projected to subspaces containing the singular point [pt
Elastic gauge fields and Hall viscosity of Dirac magnons
Ferreiros, Yago; Vozmediano, María A. H.
2018-02-01
We analyze the coupling of elastic lattice deformations to the magnon degrees of freedom of magnon Dirac materials. For a honeycomb ferromagnet we find that, as happens in the case of graphene, elastic gauge fields appear coupled to the magnon pseudospinors. For deformations that induce constant pseudomagnetic fields, the spectrum around the Dirac nodes splits into pseudo-Landau levels. We show that when a Dzyaloshinskii-Moriya interaction is considered, a topological gap opens in the system and a Chern-Simons effective action for the elastic degrees of freedom is generated. Such a term encodes a phonon Hall viscosity response, entirely generated by quantum fluctuations of magnons living in the vicinity of the Dirac points. The magnon Hall viscosity vanishes at zero temperature, and grows as temperature is raised and the states around the Dirac points are increasingly populated.
Calibration and characterization of Bayard-Alpert gauges operating in high magnetic fields
International Nuclear Information System (INIS)
Pickles, W.L.; Hunt, A.L.
1985-11-01
Standard Bayard-Alpert gauges have been successfully operated for several months in the 0.3 to 0.7 T magnetic fields near the plasma edge of the Tandem Mirror Experiment-Upgrade (TMX-U). The gauges clearly measure gas pressure and maintain calibration within 10% during operation. The gauge filaments are tungsten and are heated with DC. The gauge housing allows operation in the low density plasma outside the limiter radius by thermalizing the neutral gas that enters the gauge and by preventing plasma from entering the gauge. Changing the orientation of the gauge with respect to the magnetic field changes the gauge calibration, or effective sensitivity, by as much as a factor of 100. Only some orientations of the filament collector plane with respect to the magnetic field direction allow calibrated operation as a pressure gauge. This range of angles is approximately from 20 to 50 degrees. The gauge is oriented to produce the desired sensitivity, then calibrated for the magnetic field effects for that position. The correction to sensitivity for magnet field is not strongly species dependent. The gauge species sensitivities for CH 4 , Xe,and Kr measured in the high magnetic fields were found to be close to the published values measured in no magnetic field
Magnetic Monopoles, Center Vortices and Topology of Gauge Fields
Reinhardt, H.; Engelhardt, M.; Langfeld, K.; Quandt, M.; Schafke, A.
1999-01-01
The topological properties of magnetic monopoles and center vortices arising, respectively, in Abelian and center gauges are studied in continuum Yang-Mills Theory. For this purpose the continuum analog of the maximum center gauge is constructed.
Magnetic monopoles, center vortices and topology of gauge fields
International Nuclear Information System (INIS)
Reinhardt, H.; Engelhardt, M.; Langfeld, K.; Quandt, M.; Schaefke, A.
2000-01-01
The topological properties of magnetic monopoles and center vortices arising, respectively, in Abelian and center gauges are studied in continuum Yang-Mills Theory. For this purpose the continuum analog of the maximum center gauge is constructed
Covariant field equations, gauge fields and conservation laws from Yang-Mills matrix models
International Nuclear Information System (INIS)
Steinacker, Harold
2009-01-01
The effective geometry and the gravitational coupling of nonabelian gauge and scalar fields on generic NC branes in Yang-Mills matrix models is determined. Covariant field equations are derived from the basic matrix equations of motions, known as Yang-Mills algebra. Remarkably, the equations of motion for the Poisson structure and for the nonabelian gauge fields follow from a matrix Noether theorem, and are therefore protected from quantum corrections. This provides a transparent derivation and generalization of the effective action governing the SU(n) gauge fields obtained in [1], including the would-be topological term. In particular, the IKKT matrix model is capable of describing 4-dimensional NC space-times with a general effective metric. Metric deformations of flat Moyal-Weyl space are briefly discussed.
Gauge boson mass without a Higgs field: a simple model
International Nuclear Information System (INIS)
Nicholson, A.F.; Kennedy, D.C.
1997-02-01
A simple, anomaly-free chiral gauge theory can be perturbatively quantized and renormalized in such a way as to generate fermion and gauge boson masses. This development exploits certain freedoms inherent in choosing the unperturbed Lagrangian and in the renormalization procedure. Apart from its intrinsic interest, such a mechanism might be employed in electroweak gauge theory to generate fermion and gauge boson masses without a Higgs sector. 38 refs
Implementability of gauge transformations and quantization of fermions in external fields
International Nuclear Information System (INIS)
Grosse, H.; Karner, G.
1986-01-01
Quantization of fermions in an external soliton field, leading to a representation of the CAR which is inequivalent to the representation connected to the massive Dirac operator, is studied. We determine classes of gauge and axial gauge transformations which can be unitarily implemented. In the latter case quantization conditions for gauge functions are obtained; integers entering can be interpreted as winding numbers. (Author)
Quantum theory of gauge fields and rigid processes calculation
International Nuclear Information System (INIS)
Andreev, I.V.
1981-01-01
Elementary statement of the basic data on the nature of quark interactions and their role in the high energy processes is presented in the first part of the paper. The second part of the paper deals with gauge theory (GT) of strong interactions (chromodynamics (CD)) and its application in calculation of rigid processes with quark participation. It is based on the method of functional integration (MFI). A comparatively simple representation of the MFI in the quantum theory and formulation of the perturbation theory for gauge fields are given. A derivation of the rules of diagram technique is presented. Renormalization invariance of the theory and the basic for CD phenomenon of asymptotical freedom are discussed. Theory application in calculation of certain effects at high energies is considered. From the CD view point considered is a parton model on the base of which ''rigid'' stage of evolution of quark and gluon jets produced at high energies can be quantitatively described and some quantitative experimental tests of the CD are suggested [ru
Gauge and matter fields coupled to N=2 supergravity
International Nuclear Information System (INIS)
Wit, B. de; Lauwers, P.G.; Philippe, R.; Su, S.-Q.; Proeyen, A. van.
1983-07-01
The authors consider the potential of a general matter system of N=2 vector and scalar multiplets coupled to supergravity. For lagrangians that are initially quadratic in the matter fields the potential is proved to be either positive or unbounded from below. The results have been obtained in the framework of a superconformal multiplet calculus, and it has been verified that they can be derived from each of the three off-shell representations. As an example the authors consider SO(6) Yang-Mills theory coupled to scalar multiplets in the 10+10 representation, which, for suitably chosen parameters, leads to the potential of gauged N=8 supergravity. Finally, a discussion of the possibility to set residual nonabelian symmetry groups after breaking of N=8 supersymmetry to N=1 or 2 is presented. (Auth.)
Gauge invariance of a particle in an external magnetic field
International Nuclear Information System (INIS)
Ekstein, H.
1978-12-01
In the accepted theory of a nonrelativistic particle in an external field, as well as in the Dirac equation, the canonical momentum p plays a strangely elusive role: contrary to the position q, it has no physical interpretation, yet it is a member of the algebra of observables; nor does it have a well-defined meaning as a translation generator. This paper proposes an observation procedure for p which entails a definite choice for the vector potential A: the radiation gauge divergence of A=0. The canonical momentum, so defined operationally, is shown to be the image of the generator of space translations, in the sense of presymmetry, as the position q is the image of the generator of Galilei boosts in nonrelativistic theories
Full spectrum of Lyapunov exponents in gauge field theories
International Nuclear Information System (INIS)
Biro, T.S.; Markum, H.; Pullirsch, R.
2003-01-01
Full text: Results are presented for the full spectrum of Lyapunov exponents of the compact U(1) gauge system in classical field theory. Instead of the determination of the largest Lyapunov exponent by the rescaling method we now use the monodromy matrix approach. The Lyapunov spectrum L i is expressed in terms of the eigenvalues Λ i of the monodromy matrix M. In the confinement phase the eigenvalues lie on either the real or on the imaginary axes. This is a nice illustration of a strange attractor of a chaotic system. Positive Lyapunov exponents eject the trajectories from oscillating orbits provided by the imaginary eigenvalues. Negative Lyapunov exponents attract the trajectories keeping them confined in the basin. Latest studies concern the time (in)dependence of the monodromy matrix. Further, we show that monopoles are created and annihilated in pairs as a function of real time in access to a fixed average monopole number. (author)
Chiral gauged Wess-Zumino-Witten theories and coset models in conformal field theory
International Nuclear Information System (INIS)
Chung, S.; Tye, S.H.
1993-01-01
The Wess-Zumino-Witten (WZW) theory has a global symmetry denoted by G L direct-product G R . In the standard gauged WZW theory, vector gauge fields (i.e., with vector gauge couplings) are in the adjoint representation of the subgroup H contained-in G. In this paper, we show that, in the conformal limit in two dimensions, there is a gauged WZW theory where the gauge fields are chiral and belong to the subgroups H L and H R where H L and H R can be different groups. In the special case where H L =H R , the theory is equivalent to vector gauged WZW theory. For general groups H L and H R , an examination of the correlation functions (or more precisely, conformal blocks) shows that the chiral gauged WZW theory is equivalent to (G/H L ) L direct-product(G/H R ) R coset models in conformal field theory
International Nuclear Information System (INIS)
Evett, S.R.; Steiner, J.L.
1995-01-01
Soil water content gauges based on neutron scattering (NS) have been a valuable tool for soil water investigations for some 40 yr. However, licensing, training, and safety regulations pertaining to the radioactive source in these gauges makes their use expensive and prevents use in some situations such as unattended monitoring. A capacitance probe (CP) gauge has characteristics that would seem to make it an ideal replacement for NS gauges. We determined the relative precision of two brands of NS gauges (three gauges of each) and a brand of CP gauge (four gauges) in a field calibration exercise. Both brands of NS gauges were calibrated vs. volumetric soil water content with coefficients of determination (r2) ranging from 0.97 to 0.99 and root mean squared errors (RMSE) 0.012 m3 m-3 water content. Calibrations for the CP gauges resulted in r2 ranging from 0.68 to 0.71 and RMSE of 0.036 m3 m-3 water content. Average 95% confidence intervals on predictions were three to five times higher for the CP gauges than for the NS gauges, ranging from 0.153 to 0.161 and 0.032 to 0.052 m3 m-3, respectively. Although poorly correlated with soil water content, readings were reproducible among the four CP gauges. The poor correlation for CP gauges may be due to small-scale soil water content variations within the measurement volume of the gauge. The NS gauges provide acceptable precision but the CP gauge has poor precision and is unacceptable for routine soil water content measurements
On infrared problems of effective Lagrangians of massive spin 2 fields coupled to gauge fields
Energy Technology Data Exchange (ETDEWEB)
Canfora, Fabrizio, E-mail: canfora@cecs.cl [Centro de Estudios Científicos (CECs), Casilla 1469, Valdivia (Chile); Giacomini, Alex, E-mail: alexgiacomini@uach.cl [Instituto de Ciencias Físicas y Matemáticas, Universidad Austral de Chile, Valdivia (Chile); Zerwekh, Alfonso R., E-mail: alfonso.zerwekh@usm.cl [Departamento de Física and Centro Científico-Tecnológico de Valparaíso, Universidad Técnica Federico Santa María, Casilla 110-V, Valparaíso (Chile)
2016-12-15
In this paper we analyze the interactions of massive spin-2 particles charged under both Abelian and non-Abelian group using the Porrati–Rahman Lagrangian. This theory is valid up to an intrinsic cutoff scale. Phenomenologically a theory valid up to a cutoff scale is sensible as all known higher spin particles are non-fundamental and it is shown that indeed this action can be used to estimate some relevant cross section. Such action necessarily includes Stückelberg field and therefore it is necessary to fix the corresponding gauge symmetry. We show that this theory, when the Stückelberg symmetry is gauge-fixed, possesses a non-trivial infrared problem. A gauge fixing ambiguity arises which is akin to the Gribov problem in QCD in the Abelian case as well. In some cases (such as when the space–time is the four-dimensional torus) the vacuum copies can be found analytically. A similar phenomenon also appears in the case of Proca fields. A very interesting feature of these copies is that they arise only for “large enough” gauge potentials. This opens the possibility to avoid the appearance of such gauge fixing ambiguities by using a Gribov–Zwanziger like approach.
Gauge theories of Yang-Mills vector fields coupled to antisymmetric tensor fields
International Nuclear Information System (INIS)
Anco, Stephen C.
2003-01-01
A non-Abelian class of massless/massive nonlinear gauge theories of Yang-Mills vector potentials coupled to Freedman-Townsend antisymmetric tensor potentials is constructed in four space-time dimensions. These theories involve an extended Freedman-Townsend-type coupling between the vector and tensor fields, and a Chern-Simons mass term with the addition of a Higgs-type coupling of the tensor fields to the vector fields in the massive case. Geometrical, field theoretic, and algebraic aspects of the theories are discussed in detail. In particular, the geometrical structure mixes and unifies features of Yang-Mills theory and Freedman-Townsend theory formulated in terms of Lie algebra valued curvatures and connections associated to the fields and nonlinear field strengths. The theories arise from a general determination of all possible geometrical nonlinear deformations of linear Abelian gauge theory for one-form fields and two-form fields with an Abelian Chern-Simons mass term in four dimensions. For this type of deformation (with typical assumptions on the allowed form considered for terms in the gauge symmetries and field equations), an explicit classification of deformation terms at first-order is obtained, and uniqueness of deformation terms at all higher orders is proven. This leads to a uniqueness result for the non-Abelian class of theories constructed here
International Nuclear Information System (INIS)
Huang Yongchang; Huo Qiuhong
2008-01-01
Using Faddeev-Senjanovic path integral quantization for constrained Hamilton system, we quantize SU(n) N=2 supersymmetric gauge field system with non-Abelian Chern-Simons topological term in 2+1 dimensions. We use consistency of Coulomb gauge condition to naturally deduce a new gauge condition. Furthermore, we obtain the generating functional of Green function in phase space, deduce the angular momentum based on the global canonical Noether theorem at quantum level, obtain the fractional spin of this supersymmetric system, and show that the total angular momentum is the sum of the orbital angular momentum and spin angular momentum of the non-Abelian gauge field. Finally, we obtain the anomalous fractional spin and discover that the fractional spin has the contributions of both the group superscript components and A 0 s (x) charge
Cosmology in Gauge Field Theory and String Theory
International Nuclear Information System (INIS)
Garcia Compean, H
2005-01-01
This new book is intended for students and researchers who want to go into the interplay between cosmology and high-energy physics. It assumes a prior knowledge of these subjects such as some of the topics contained in the previous books by the authors, Introduction to Gauge Field Theory (1993 Bristol: Institute of Physics Publishing) and Supersymmetric Gauge Field Theory and String Theory (1994 Bristol: Institute of Physics Publishing). However, the book is intended to be self-contained, explaining, from a modern perspective, some background material mainly in standard cosmology, topological defects, baryogenesis, inflationary cosmology and, at the end of the book, some of the basics of string theory. What is distinctively new about this book is that it lies in the interplay between cosmology and high-energy physics typically above 100 GeV (10 15 K). Often these subjects are presented in regular textbooks in a disconnected way, or in research papers, proceedings and review papers but usually not in a pedagogical style. Thus, in this sense, the book is unique and deserves a special place in the recent literature. The book starts by reviewing the standard material of the early universe. The standard model of cosmology from a modern perspective is revised in chapter 1. In chapter 2, phase transitions in different models are discussed, Higgs, electroweak, GUTs, supersymmetric GUTs and supergravity, by using quantum field theory at finite temperature. Chapter 3 is devoted to a general account of topological defects and discusses how they arise as possible remnants of these phase transitions in GUTs. Other relics, such as neutrinos and axions, are introduced in chapter 5 and their impact in cosmology is assessed. In chapter 4, some of the most relevant mechanisms of baryogenesis are discussed in the context of the different GUTs and the minimal supersymmetric standard model (MSSM). Inflation is also discussed in the context of GUTs. In chapter 6, the authors introduce
Light-cone gauge approach to arbitrary spin fields, currents and shadows
International Nuclear Information System (INIS)
Metsaev, R R
2014-01-01
Totally symmetric arbitrary spin fields in AdS space, conformal fields, conformal currents, and shadow fields in flat space are studied. Light-cone gauge formulations for such fields, currents and shadows are obtained. Use of the Poincaré parametrization of AdS space and ladder operators allows us to treat fields in flat and AdS spaces on an equal footing. Light-cone gauge realization of relativistic symmetries for fields, currents and shadows is also obtained. The light-cone gauge formulation for fields is obtained by using the gauge invariant Lagrangian which is presented in terms of modified de Donder divergence, while the light-cone gauge formulation for currents and shadows is obtained by using the gauge invariant approach to currents and shadows. This allows us to demonstrate explicitly how the ladder operators entering the gauge invariant formulation of fields, currents and shadows manifest themselves in the light-cone gauge formulation for fields, currents and shadows. (paper)
Gluon field strength correlation functions within a constrained instanton model
International Nuclear Information System (INIS)
Dorokhov, A.E.; Esaibegyan, S.V.; Maximov, A.E.; Mikhailov, S.V.
2000-01-01
We suggest a constrained instanton (CI) solution in the physical QCD vacuum which is described by large-scale vacuum field fluctuations. This solution decays exponentially at large distances. It is stable only if the interaction of the instanton with the background vacuum field is small and additional constraints are introduced. The CI solution is explicitly constructed in the ansatz form, and the two-point vacuum correlator of the gluon field strengths is calculated in the framework of the effective instanton vacuum model. At small distances the results are qualitatively similar to the single instanton case; in particular, the D 1 invariant structure is small, which is in agreement with the lattice calculations. (orig.)
Gauged BRST symmetry and the occurence of higher cocycles in quantum field theory
International Nuclear Information System (INIS)
Baulieu, L.; Grossman, B.; Stora, R.
1986-06-01
The BRST symmetry of Yang Mills theories can be gauged via the introduction of an anticommuting single gauge field. There follows the construction of a local BRST operation which allows an algebraic analysis of the BRST current algebra. This construction provides, in particular, a field theory interpretation of most higher cocycles which accompany the usual chiral anomaly
Ultraviolet stability of three-dimensional lattice pure gauge field theories
International Nuclear Information System (INIS)
Balaban, T.
1985-01-01
We prove the ultraviolet stability for three-dimensional lattice gauge field theories. We consider only the Wilson lattice approximation for pure Yang-Mills field theories. The proof is based on results of the previous papers on renormalization group method for lattice gauge theories. (orig.)
Possible physical manifestation of the Weyl non-Abelian gauge field
International Nuclear Information System (INIS)
Barbashov, B.M.; Pestov, A.B.
1998-01-01
On the basis of the Weyl equations of congruent transference, we consider a possible influence of the Weyl non-Abelian gauge field defining the transference on the precession of a gyroscope. Plane-wave solutions to the equations of the Abelian gauge field are derived
Gauge fields in nonlinear group realizations involving two-dimensional space-time symmetry
International Nuclear Information System (INIS)
Machacek, M.E.; McCliment, E.R.
1975-01-01
It is shown that gauge fields may be consistently introduced into a model Lagrangian previously considered by the authors. The model is suggested by the spontaneous breaking of a Lorentz-type group into a quasiphysical two-dimensional space-time and one internal degree of freedom, loosely associated with charge. The introduction of zero-mass gauge fields makes possible the absorption via the Higgs mechanism of the Goldstone fields that appear in the model despite the fact that the Goldstone fields do not transform as scalars. Specifically, gauge invariance of the Yang-Mills type requires the introduction of two sets of massless gauge fields. The transformation properties in two-dimensional space-time suggest that one set is analogous to a charge doublet that behaves like a second-rank tensor in real four-dimensional space time. The other set suggests a spin-one-like charge triplet. Via the Higgs mechanism, the first set absorbs the Goldstone fields and acquires mass. The second set remains massless. If massive gauge fields are introduced, the associated currents are not conserved and the Higgs mechanism is no longer fully operative. The Goldstone fields are not eliminated, but coupling between the Goldstone fields and the gauge fields does shift the mass of the antisymmetric second-rank-tensor gauge field components
Unveiling a spinor field classification with non-Abelian gauge symmetries
Fabbri, Luca; da Rocha, Roldão
2018-05-01
A spinor fields classification with non-Abelian gauge symmetries is introduced, generalizing the U(1) gauge symmetries-based Lounesto's classification. Here, a more general classification, contrary to the Lounesto's one, encompasses spinor multiplets, corresponding to non-Abelian gauge fields. The particular case of SU(2) gauge symmetry, encompassing electroweak and electromagnetic conserved charges, is then implemented by a non-Abelian spinor classification, now involving 14 mixed classes of spinor doublets. A richer flagpole, dipole, and flag-dipole structure naturally descends from this general classification. The Lounesto's classification of spinors is shown to arise as a Pauli's singlet, into this more general classification.
Physical principles, geometrical aspects, and locality properties of gauge field theories
International Nuclear Information System (INIS)
Mack, G.; Hamburg Univ.
1981-01-01
Gauge field theories, particularly Yang - Mills theories, are discussed at a classical level from a geometrical point of view. The introductory chapters are concentrated on physical principles and mathematical tools. The main part is devoted to locality problems in gauge field theories. Examples show that locality problems originate from two sources in pure Yang - Mills theories (without matter fields). One is topological and the other is related to the existence of degenerated field configurations of the infinitesimal holonomy groups on some extended region of space or space-time. Nondegenerate field configurations in theories with semisimple gauge groups can be analysed with the help of the concept of a local gauge. Such gauges play a central role in the discussion. (author)
Gravitational waves from non-Abelian gauge fields at a tachyonic transition
Tranberg, Anders; Tähtinen, Sara; Weir, David J.
2018-04-01
We compute the gravitational wave spectrum from a tachyonic preheating transition of a Standard Model-like SU(2)-Higgs system. Tachyonic preheating involves exponentially growing IR modes, at scales as large as the horizon. Such a transition at the electroweak scale could be detectable by LISA, if these non-perturbatively large modes translate into non-linear dynamics sourcing gravitational waves. Through large-scale numerical simulations, we find that the spectrum of gravitational waves does not exhibit such IR features. Instead, we find two peaks corresponding to the Higgs and gauge field mass, respectively. We find that the gravitational wave production is reduced when adding non-Abelian gauge fields to a scalar-only theory, but increases when adding Abelian gauge fields. In particular, gauge fields suppress the gravitational wave spectrum in the IR. A tachyonic transition in the early Universe will therefore not be detectable by LISA, even if it involves non-Abelian gauge fields.
Gauge-invariant expectation values of the energy of a molecule in an electromagnetic field
International Nuclear Information System (INIS)
Mandal, Anirban; Hunt, Katharine L. C.
2016-01-01
In this paper, we show that the full Hamiltonian for a molecule in an electromagnetic field can be separated into a molecular Hamiltonian and a field Hamiltonian, both with gauge-invariant expectation values. The expectation value of the molecular Hamiltonian gives physically meaningful results for the energy of a molecule in a time-dependent applied field. In contrast, the usual partitioning of the full Hamiltonian into molecular and field terms introduces an arbitrary gauge-dependent potential into the molecular Hamiltonian and leaves a gauge-dependent form of the Hamiltonian for the field. With the usual partitioning of the Hamiltonian, this same problem of gauge dependence arises even in the absence of an applied field, as we show explicitly by considering a gauge transformation from zero applied field and zero external potentials to zero applied field, but non-zero external vector and scalar potentials. We resolve this problem and also remove the gauge dependence from the Hamiltonian for a molecule in a non-zero applied field and from the field Hamiltonian, by repartitioning the full Hamiltonian. It is possible to remove the gauge dependence because the interaction of the molecular charges with the gauge potential cancels identically with a gauge-dependent term in the usual form of the field Hamiltonian. We treat the electromagnetic field classically and treat the molecule quantum mechanically, but nonrelativistically. Our derivation starts from the Lagrangian for a set of charged particles and an electromagnetic field, with the particle coordinates, the vector potential, the scalar potential, and their time derivatives treated as the variables in the Lagrangian. We construct the full Hamiltonian using a Lagrange multiplier method originally suggested by Dirac, partition this Hamiltonian into a molecular term H m and a field term H f , and show that both H m and H f have gauge-independent expectation values. Any gauge may be chosen for the calculations; but
Magnetic monopoles, center vortices, confinement and topology of gauge fields
International Nuclear Information System (INIS)
Reinhardt, H.; Engelhardt, M.; Langfeld, K.; Quandt, M.; Schaefke, A.
2000-01-01
The vortex picture of confinement is studied. The deconfinement phase transition is explained as a transition from a phase in which vortices percolate to a phase of small vortices. Lattice results are presented in support of this scenario. Furthermore the topological properties of magnetic monopoles and center vortices arising, respectively, in Abelian and center gauges are studied in continuum Yang-Mills-theory. For this purpose the continuum analog of the maximum center gauge is constructed
Magnetic Monopoles, Center Vortices, Confinement and Topology of Gauge Fields
Reinhardt, H.; Engelhardt, M.; Langfeld, K.; Quandt, M.; Sch"afke, A.
1999-01-01
The vortex picture of confinement is studied. The deconfinement phase transition is explained as a transition from a phase in which vortices percolate to a phase of small vortices. Lattice results are presented in support of this scenario. Furthermore the topological properties of magnetic monopoles and center vortices arising, respectively, in Abelian and center gauges are studied in continuum Yang-Mills-theory. For this purpose the continuum analog of the maximum center gauge is constructed.
Geometrodynamics of gauge fields on the geometry of Yang-Mills and gravitational gauge theories
Mielke, Eckehard W
2016-01-01
This monograph aims to provide a unified, geometrical foundation of gauge theories of elementary particle physics. The underlying geometrical structure is unfolded in a coordinate-free manner via the modern mathematical notions of fibre bundles and exterior forms. Topics such as the dynamics of Yang-Mills theories, instanton solutions and topological invariants are included. By transferring these concepts to local space-time symmetries, generalizations of Einstein's theory of gravity arise in a Riemann-Cartan space with curvature and torsion. It provides the framework in which the (broken) Poincaré gauge theory, the Rainich geometrization of the Einstein-Maxwell system, and higher-dimensional, non-abelian Kaluza-Klein theories are developed. Since the discovery of the Higgs boson, concepts of spontaneous symmetry breaking in gravity have come again into focus, and, in this revised edition, these will be exposed in geometric terms. Quantizing gravity remains an open issue: formulating it as a de Sitter t...
Metal–insulator crossover in high Tc cuprates: A gauge field approach
Indian Academy of Sciences (India)
plane resistivity of underdoped cuprates and a range of superconducting cuprates in the presence of a strong magnetic field suppressing superconductivity. We propose an explanation for this phenomenon based on a gauge field theory approach ...
Constraining scalar fields with stellar kinematics and collisional dark matter
International Nuclear Information System (INIS)
Amaro-Seoane, Pau; Barranco, Juan; Bernal, Argelia; Rezzolla, Luciano
2010-01-01
The existence and detection of scalar fields could provide solutions to long-standing puzzles about the nature of dark matter, the dark compact objects at the centre of most galaxies, and other phenomena. Yet, self-interacting scalar fields are very poorly constrained by astronomical observations, leading to great uncertainties in estimates of the mass m φ and the self-interacting coupling constant λ of these fields. To counter this, we have systematically employed available astronomical observations to develop new constraints, considerably restricting this parameter space. In particular, by exploiting precise observations of stellar dynamics at the centre of our Galaxy and assuming that these dynamics can be explained by a single boson star, we determine an upper limit for the boson star compactness and impose significant limits on the values of the properties of possible scalar fields. Requiring the scalar field particle to follow a collisional dark matter model further narrows these constraints. Most importantly, we find that if a scalar dark matter particle does exist, then it cannot account for both the dark-matter halos and the existence of dark compact objects in galactic nuclei
Yuji, NAKAWAKI; Azuma, TANAKA; Kazuhiko, OZAKI; Division of Physics and Mathematics, Faculty of Engineering Setsunan University; Junior College of Osaka Institute of Technology; Faculty of General Education, Osaka Institute of Technology
1994-01-01
Gauge Equivalence of the A_3=0 (axial) gauge to the Coulomb gauge is directly verified in QED. For that purpose a pair of conjugate zero-norm fields are introduced. This enables us to construct a canonical formulation in the axial gauge embedded in the indefinite metric Hilbert space in such a way that the Feynman rules are not altered. In the indefinite metric Hilbert space we can implement a gauge transformation, which otherwise has to be carried out only by hand, as main parts of a canonic...
Gauge-field topology in two dimensions: θ-vacuum, topological phases and composite fields
International Nuclear Information System (INIS)
Ilieva, N.; Pervushin, V.N.
1990-06-01
In the framework of the minimal quantization method, the residual 'longitudinal' vacuum dynamics of the Abelian gauge field, that is described by a new pair of canonical variables, is revealed. This dynamics is shown to give origin to the θ-vacuum, thus providing a field analogy of the Josephson effect. The destructive interference of the topological phases - that the fermion fields are shown to acquire - is considered as a reason for the charge screening in the two-dimensional massless QED. (author). 11 refs
Field-theoretical investigations in nonlinear realizations of gauge symmetry
International Nuclear Information System (INIS)
Lee, Chenhan.
1989-01-01
A review of both linear realization and non-linear realization of gauge symmetries is given and the connection between the two recipes is carefully examined. The author then constructs both linear and non-linear realizations for of supersymmetric theories. The supermultiplets of the Goldstone modes contain Goldstone bosons, quasi-Goldstone bosons and quasi-Goldstone fermions. He makes an attempt to construct a specific model of a supersymmetric non-linear realization for the Nambu-Goldstone superfields and the quasi-Goldstone fermions are identified with the quarks and leptons. Further, he discusses a mechanism by which the components of the Nambu-Goldstone supermultiplets are given non-zero mass splittings by the coupling to a hidden sector. Next, he turns to anti-symmetric tensor gauge theories, which are shown to be classically equivalent to the non-linear models describing the complete symmetry breakdown. To study the quantum mechanical equivalence of these two models, he carries out the tensor gauge fixing and the quantization procedures for the anti-symmetric tensor theories and establish the global symmetry currents which connect the two models. He then builds the supersymmetric extensions of the anti-symmetric tensor gauge theories in both abelian and non-abelian versions. Such super-tensor gauge theories are shown, by using the superfield equations of motion, to be equivalent to the fully doubled supersymmetric non-linear models of complete symmetry breakdown
Stochastic quantization and gauge-fixing of the linearized gravitational field
International Nuclear Information System (INIS)
Hueffel, H.; Rumpf, H.
1984-01-01
Due to the indefiniteness of the Euclidean gravitational action the Parisi-Wu stochastic quantization scheme fails in the case of the gravitational field. Therefore we apply a recently proposed modification of stochastic quantization that works in Minkowski space and preserves all the advantages of the original Parisi-Wu method; in particular no gauge-fixing is required. Additionally stochastic gauge-fixing may be introduced and is also studied in detail. The graviton propagators obtained with and without stochastic gauge-fixing all exhibit a noncausal contribution, but apart from this effect the gauge-invariant quantities are the same as those of standard quantization. (Author)
Towards a coupled-cluster treatment of SU(N) lattice gauge field theory
Bishop, Raymond F.; Ligterink, N.E.; Walet, Niels R.
2006-01-01
A consistent approach to Hamiltonian SU(N) lattice gauge field theory is developed using the maximal-tree gauge and an appropriately chosen set of angular variables. The various constraints are carefully discussed, as is a practical means for their implementation. A complete set of variables for the
Noncontractible hyperloops in gauge models with Higgs fields in the fundamental representation
Burzlaff, Jürgen
1984-11-01
We study finite-energy configurations in SO( N) gauge theories with Higgs fields in the fundamental representation. For all winding numbers, noncontractible hyperloops are constructed. The corresponding energy density is spherically symmetric, and the configuration with maximal energy on each hyperloop can be determined. Noncontractible hyperloops with an arbitrary winding number for SU(2) gauge theory are also given.
Noncontractible hyperloops in gauge models with Higgs fields in the fundamental representation
International Nuclear Information System (INIS)
Burzlaff, J.
1984-01-01
We study finite-energy configurations in SO(N) gauge theories with Higgs fields in the fundamental representation. For all winding numbers, noncontractible hyperloops are constructed. The corresponding energy density is spherically symmetric, and the configuration with maximal energy on each hyperloop can be determined. Noncontractible hyperloops with an arbitrary winding number for SU(2) gauge theory are also given. (orig.)
Noncontractible hyperloops in gauge models with Higgs fields in the fundamental representation
Energy Technology Data Exchange (ETDEWEB)
Burzlaff, J. (Dublin Inst. for Advanced Studies (Ireland). School of Theoretical Physics)
1984-11-01
We study finite-energy configurations in SO(N) gauge theories with Higgs fields in the fundamental representation. For all winding numbers, noncontractible hyperloops are constructed. The corresponding energy density is spherically symmetric, and the configuration with maximal energy on each hyperloop can be determined. Noncontractible hyperloops with an arbitrary winding number for SU(2) gauge theory are also given.
Energy Technology Data Exchange (ETDEWEB)
Kubo, R; Takahashi, Y; Yokoyama, K
1975-01-01
In a wide class of neutral vector field theories, in which massive and massless fields are described in a unified way and a unique massless limit exists to quantum electrodynamics in covariant gauges, the commutability of the scale transformation and the massless limit is examined. It is shown that there occurs no anomaly with respect to the assignment for scale dimensions of relevant fields. Connection of scale transformation and gauge transformation is also discussed.
Balancing anisotropic curvature with gauge fields in a class of shear-free cosmological models
Thorsrud, Mikjel
2018-05-01
We present a complete list of general relativistic shear-free solutions in a class of anisotropic, spatially homogeneous and orthogonal cosmological models containing a collection of n independent p-form gauge fields, where p\\in\\{0, 1, 2, 3\\} , in addition to standard ΛCDM matter fields modelled as perfect fluids. Here a (collection of) gauge field(s) balances anisotropic spatial curvature on the right-hand side of the shear propagation equation. The result is a class of solutions dynamically equivalent to standard FLRW cosmologies, with an effective curvature constant Keff that depends both on spatial curvature and the energy density of the gauge field(s). In the case of a single gauge field (n = 1) we show that the only spacetimes that admit such solutions are the LRS Bianchi type III, Bianchi type VI0 and Kantowski–Sachs metric, which are dynamically equivalent to open (Keff0 ) FLRW models, respectively. With a collection of gauge fields (n > 1) also Bianchi type II admits a shear-free solution (Keff>0 ). We identify the LRS Bianchi type III solution to be the unique shear-free solution with a gauge field Hamiltonian bounded from below in the entire class of models.
Axial-gauge formulation of a three-dimensional field theory
International Nuclear Information System (INIS)
Hagen, C.R.
1985-01-01
Since the non-Abelian version of a recently formulated gauge theory in two spatial dimensions gives rise to a nonlinear constraint upon the fields in the radiation-gauge approach, one is motivated to attempt a description in terms of the axial gauge. This is accomplished in the Abelian version of the model, with results similar to those encountered in the radiation gauge. The non-Abelian case is then formally solved in the same gauge, it being subsequently shown, however, that the theory is not covariant. It is argued on the basis of perturbation theory that such noncovariance is a real effect which is not readily circumvented by modification of the field transformation properties
Directory of Open Access Journals (Sweden)
S. Vogl
2012-07-01
Full Text Available This study addresses the problem of combining radar information and gauge measurements. Gauge measurements are the best available source of absolute rainfall intensity albeit their spatial availability is limited. Precipitation information obtained by radar mimics well the spatial patterns but is biased for their absolute values.
In this study copula models are used to describe the dependence structure between gauge observations and rainfall derived from radar reflectivity at the corresponding grid cells. After appropriate time series transformation to generate "iid" variates, only the positive pairs (radar >0, gauge >0 of the residuals are considered. As not each grid cell can be assigned to one gauge, the integration of point information, i.e. gauge rainfall intensities, is achieved by considering the structure and the strength of dependence between the radar pixels and all the gauges within the radar image. Two different approaches, namely Maximum Theta and Multiple Theta, are presented. They finally allow for generating precipitation fields that mimic the spatial patterns of the radar fields and correct them for biases in their absolute rainfall intensities. The performance of the approach, which can be seen as a bias-correction for radar fields, is demonstrated for the Bavarian Alps. The bias-corrected rainfall fields are compared to a field of interpolated gauge values (ordinary kriging and are validated with available gauge measurements. The simulated precipitation fields are compared to an operationally corrected radar precipitation field (RADOLAN. The copula-based approach performs similarly well as indicated by different validation measures and successfully corrects for errors in the radar precipitation.
Energy Technology Data Exchange (ETDEWEB)
Kubo, R; Yokoyama, K
1974-11-01
The purpose of this work is to study the structure of c-number gauge transformation in connection with renormalization problem. In the wide theory of neutral vector fields, there is the gauge structure described essentially by free Lagrangian density. The c-number gauge transformation makes the Lagrangian invariant correspondingly to the usual case of quantum electrodynamics. The c-number transformation can be used to derive relationships among all relevant renormalization constants in the case of interacting fields. In the presence of interaction, total Lagrangian density L is written as L=L/sub 0/+L/sub 1/+L/sub 2/, where L/sub 1/ is given from matter-field Lagrangian density, and L/sub 2/ denotes necessary additional counter terms. In order to conserve the gauge structure, the form of L is invariant under the gauge transformation. Since L matter is self-adjoining, L/sub 1/ remains invariant by itself under the transformation. The form of L/sub 2/ is finally given from the observation that L/sub 3/ cannot contain wave-function renormalization constants. Since L/sub 2/ is invariant under q-number gauge transformation, this transformation in unrenormalized form makes the present L form-invariant. Therefore, together with the above results, auxiliary fields produce the q-number gauge transformation for renormalized fields.
On the notion of Jacobi fields in constrained calculus of variations
Directory of Open Access Journals (Sweden)
Massa Enrico
2016-12-01
Full Text Available In variational calculus, the minimality of a given functional under arbitrary deformations with fixed end-points is established through an analysis of the so called second variation. In this paper, the argument is examined in the context of constrained variational calculus, assuming piecewise differentiable extremals, commonly referred to as extremaloids. The approach relies on the existence of a fully covariant representation of the second variation of the action functional, based on a family of local gauge transformations of the original Lagrangian and on a set of scalar attributes of the extremaloid, called the corners' strengths [16]. In dis- cussing the positivity of the second variation, a relevant role is played by the Jacobi fields, defined as infinitesimal generators of 1-parameter groups of diffeomorphisms preserving the extremaloids. Along a piecewise differentiable extremal, these fields are generally discontinuous across the corners. A thorough analysis of this point is presented. An alternative characterization of the Jacobi fields as solutions of a suitable accessory variational problem is established.
On the relation between fields and potentials in non abelian Gauge Theories
International Nuclear Information System (INIS)
Bollini, C.G.; Giambiagi, J.J.
1979-01-01
Some examples have been given in the literature of ambiguous gauge fields, i.e. those not having a unique potential (up to a gauge transformation). An example given by Deser and Wilczek is examined and found the condition (for any gauge group) that the group element generating the potentials must satisfy in order for the potentials not to be related by any gauge transformation. In three dimensions (for Su 2 ) there are other families of ambiguous fields characterized by arbitrary unit vector fields n vector (n vector) (n 2 vector =1). The example given by Wu and Yang belongs to a particular family with n vector = n vector. r vector / r vector. The sources of these fields and some interesting relations between them are also found [pt
A short proof that the Coulomb-gauge potentials yield the retarded fields
Energy Technology Data Exchange (ETDEWEB)
Heras, Jose A, E-mail: herasgomez@gmail.co [Universidad Autonoma Metropolitana, Unidad Azcapotzalco, Av. San Pablo No. 180, Col. Reynosa, Mexico D. F. 02200 (Mexico)
2011-01-15
A short demonstration that the potentials in the Coulomb gauge yield the retarded electric and magnetic fields is presented. This demonstration is relatively simple and can be presented in an advanced undergraduate course of electromagnetic theory.
A short proof that the Coulomb-gauge potentials yield the retarded fields
International Nuclear Information System (INIS)
Heras, Jose A
2011-01-01
A short demonstration that the potentials in the Coulomb gauge yield the retarded electric and magnetic fields is presented. This demonstration is relatively simple and can be presented in an advanced undergraduate course of electromagnetic theory.
International Nuclear Information System (INIS)
Veliev, E.S.
2004-01-01
According to Thermal Quantum Chromodynamics (TQCD) hadron matter may be exist in different phase states, in particular, in the form of quark-gluon plasma (QGP). The aim of the present work is to investigate the screening of chromoelectric and chromomagnetic fields in QGP in temporal gauge. In temporal gauge gluon propagator has the unphysical poles. Hence, in the gluon self energy diagram calculations the singularities appear. In order to remove these singularities we used Leibbrandt-Mandelstam prescription. We obtained that chromoelectric fields are screened, but chromomagnetic fields are not screened. In coordinate space, the screening of chromoelectric fields reduces the range of gauge interactions. In momentum space, it contributes to regulate the infrared behavior of the various n-point Green functions. Also, it is shown that the obtained results are gauge invariant
Gauge invariant frequency splitting of the continuum Yang-Mills field
International Nuclear Information System (INIS)
Mitter, P.K.; Valent, G.
1977-01-01
Frequency splitting plays an important role in Wilson's theory of critical phenomena. Here the authors give a theory of gauge invariant frequency splitting of the Yang-Mills field in 4 dimensions. (Auth.)
Consistent equations for interacting gauge fields of all spins in 3+1 dimensions
Energy Technology Data Exchange (ETDEWEB)
Vasiliev, M A [AN SSSR, Moscow. Inst. Teoreticheskoj Fiziki (USSR)
1990-07-05
Consistent equations of motion of interacting gauge fields of all spins in 3+1 dimensions are formulated in a closed form. These equations are explicitly general coordinate invariant, possess all necessary higher spin gauge symmetries and reduce to the usual equations of free massless fields of all spins s=0, 1/2, 1, ..., {infinity} at the linearized level. In the spin-2 sector, the proposed equations are equivalent to the Einstein equations with the cosmological term. (orig.).
Decoupling Subtraction Conserving Full Gauge Symmetries : Particles and Fields
Noriyasu, OHTSUBO; Hideo, MIYATA; Department of Phycics, Kanazawa Technical College; Department of Information Science, Kanazawa Institute of Technolgy
1984-01-01
A new subtraction scheme (^^^) which realizes the decoupling and conserves the symmetries of full gauge group simultaneously, is proposed. One particle irreducible Green's functions subtracted by ^^^ reveal the effective low energy symmetries at -p^2≪M^2 and the full symmetries at -p^2≫M^2, where M denotes a heavy mass. Also discussed are conditions in order to carry out ^^^ under two-loop approximation.
Blockspin and multigrid for staggered fermions in non-abelian gauge fields
International Nuclear Information System (INIS)
Kalkreuter, T.; Mack, G.; Speh, M.
1991-07-01
We discuss blockspins for staggered fermions, i.e. averaging and interpolation procedures which are needed in a real space renormalization group approach to gauge theories with staggered fermions and in a multigrid approach to the computation of gauge covariant propagators. The discussion starts from the requirement that the symmetries of the free action should be preserved by the blocking procedure in the limit of a pure gauge. A definition of an averaging kernel as a solution of a gauge covariant eigenvalue equation is proposed, and the properties of a corresponding interpolation kernel are examined in the light of general criteria for good choices of blockspins. Some results of multigrid computation of bosonic propagation in an SU(2) gauge field in 4 dimensions are also presented. (orig.)
Gauge bridges in classical field theory; Eichbruecken in der klassischen Feldtheorie
Energy Technology Data Exchange (ETDEWEB)
Jakobs, S.
2009-03-15
In this thesis Poisson structures of two classical gauge field theories (Maxwell-Klein-Gordon- and Maxwell-Dirac-system) are constructed using the parametrix construction of Green's functions. Parametrices for the Maxwell-Klein-Gordon- and Maxwell-Dirac-system are constructed in Minkowski space and this construction is later generalized to curved space times for the Maxwell-Klein-Gordon-system. With these Green's functions Poisson brackets will be defined as Peierls brackets. Finally non-local, gauge invariant observables, the so-called 'gauge bridges'are constructed. Gauge bridges are the matrix elements of holonomy operators. It is shown, that these emerge from Poisson brackets of local, gauge invariant observables. (orig.)
Renormalization of gauge theories in the background-field approach arXiv
Barvinsky, Andrei O.; Herrero-Valea, Mario; Sibiryakov, Sergey M.; Steinwachs, Christian F.
Using the background-field method we demonstrate the Becchi-Rouet-Stora-Tyutin (BRST) structure of counterterms in a broad class of gauge theories. Put simply, we show that gauge invariance is preserved by renormalization in local gauge field theories whenever they admit a sensible background-field formulation and anomaly-free path integral measure. This class encompasses Yang-Mills theories (with possibly Abelian subgroups) and relativistic gravity, including both renormalizable and non-renormalizable (effective) theories. Our results also hold for non-relativistic models such as Yang-Mills theories with anisotropic scaling or Horava gravity. They strengthen and generalize the existing results in the literature concerning the renormalization of gauge systems. Locality of the BRST construction is emphasized throughout the derivation. We illustrate our general approach with several explicit examples.
Antisymmetric tensor Zp gauge symmetries in field theory and string theory
International Nuclear Information System (INIS)
Berasaluce-González, Mikel; Ramírez, Guillermo; Uranga, Angel M.
2014-01-01
We consider discrete gauge symmetries in D dimensions arising as remnants of broken continuous gauge symmetries carried by general antisymmetric tensor fields, rather than by standard 1-forms. The lagrangian for such a general Z p gauge theory can be described in terms of a r-form gauge field made massive by a (r−1)-form, or other dual realizations, that we also discuss. The theory contains charged topological defects of different dimensionalities, generalizing the familiar charged particles and strings in D=4. We describe realizations in string theory compactifications with torsion cycles, or with background field strength fluxes. We also provide examples of non-abelian discrete groups, for which the group elements are associated with charged objects of different dimensionality
Theory of a gauge gravitational field at localization of the Einstein group
International Nuclear Information System (INIS)
Tunyak, V.N.
1985-01-01
Theory of a gauge gravitational field when localizing a group of movements of the Einstein homogeneous static Universe (the R x SO Einstein group (4)) has been formulated. Proceeding from tetrade components of the Einstein Universe the relation between the Riemann metrics and gauge fields of the Einstein group has been established. Metric coherence with torsion transforming to the Kristoffel coherence of the Einstein Universe has been found when switching out gauge fields. It is shown that within the limit of infinite radius of the Einstein Universe curvature the given Einstein-invariant gauge theory transforms to the tetrade gravitation theory with localized triade rotations. Exact solutions in the form of nonsingular cosmological models have been obtained
A field theory description of constrained energy-dissipation processes
International Nuclear Information System (INIS)
Mandzhavidze, I.D.; Sisakyan, A.N.
2002-01-01
A field theory description of dissipation processes constrained by a high-symmetry group is given. The formalism is presented in the example of the multiple-hadron production processes, where the transition to the thermodynamic equilibrium results from the kinetic energy of colliding particles dissipating into hadron masses. The dynamics of these processes is restricted because the constraints responsible for the colour charge confinement must be taken into account. We develop a more general S-matrix formulation of the thermodynamics of nonequilibrium dissipative processes and find a necessary and sufficient condition for the validity of this description; this condition is similar to the correlation relaxation condition, which, according to Bogolyubov, must apply as the system approaches equilibrium. This situation must physically occur in processes with an extremely high multiplicity, at least if the hadron mass is nonzero. We also describe a new strong-coupling perturbation scheme, which is useful for taking symmetry restrictions on the dynamics of dissipation processes into account. We review the literature devoted to this problem
Nonperturbative scale anomaly and composite operators in gauge field theories
International Nuclear Information System (INIS)
Gusynin, V.P.; Miranskij, V.A.
1987-01-01
In non-asymptotically free gauge theories with a non-trivial ultraviolet fixed point scale symmetry breaking (the scale anomaly) caused by the nonperturbative PCAC dynamics is studied. In the two-loop approximation the analytical expression for the gluon condensate is obtained. It is shown that the form of the anomaly depends on the type of the phase of a theory to which it relates. The hypothesis about the soft behaviour at small distances of composite operators in such theories is confirmed. 14 refs.; 1 fig
Root Structures of Infinite Gauge Groups and Supersymmetric Field Theories
International Nuclear Information System (INIS)
Catto, Sultan; Gürcan, Yasemin; Khalfan, Amish; Kurt, Levent
2013-01-01
We show the relationship between critical dimensions of supersymmetric fundamental theories and dimensions of certain Jordan algebras. In our approach position vectors in spacetime or in superspace are endowed with algebraic properties that are present only in those critical dimensions. A uniform construction of super Poincaré groups in these dimensions will be shown. Some applications of these algebraic methods to hidden symmetries present in the covariant and interacting string Lagrangians and to superparticle will be discussed. Algebraic methods we develop will be shown to generate the root structure of some infinite groups that play the role of gauge groups in a second quantized theory of strings
Gauge-fields and integrated quantum-classical theory
International Nuclear Information System (INIS)
Stapp, H.P.
1986-01-01
Physical situations in which quantum systems communicate continuously to their classically described environment are not covered by contemporary quantum theory, which requires a temporary separation of quantum degrees of freedom from classical ones. A generalization would be needed to cover these situations. An incomplete proposal is advanced for combining the quantum and classical degrees of freedom into a unified objective description. It is based on the use of certain quantum-classical structures of light that arise from gauge invariance to coordinate the quantum and classical degrees of freedom. Also discussed is the question of where experimenters should look to find phenomena pertaining to the quantum-classical connection. 17 refs
Lattice implementation of Abelian gauge theories with Chern-Simons number and an axion field
Figueroa, Daniel G.; Shaposhnikov, Mikhail
2018-01-01
Real time evolution of classical gauge fields is relevant for a number of applications in particle physics and cosmology, ranging from the early Universe to dynamics of quark-gluon plasma. We present an explicit non-compact lattice formulation of the interaction between a shift-symmetric field and some U (1) gauge sector, a (x)FμνF˜μν, reproducing the continuum limit to order O (dxμ2) and obeying the following properties: (i) the system is gauge invariant and (ii) shift symmetry is exact on the lattice. For this end we construct a definition of the topological number density K =FμνF˜μν that admits a lattice total derivative representation K = Δμ+ Kμ, reproducing to order O (dxμ2) the continuum expression K =∂μKμ ∝ E → ṡ B → . If we consider a homogeneous field a (x) = a (t), the system can be mapped into an Abelian gauge theory with Hamiltonian containing a Chern-Simons term for the gauge fields. This allow us to study in an accompanying paper the real time dynamics of fermion number non-conservation (or chirality breaking) in Abelian gauge theories at finite temperature. When a (x) = a (x → , t) is inhomogeneous, the set of lattice equations of motion do not admit however a simple explicit local solution (while preserving an O (dxμ2) accuracy). We discuss an iterative scheme allowing to overcome this difficulty.
Lattice implementation of Abelian gauge theories with Chern–Simons number and an axion field
Directory of Open Access Journals (Sweden)
Daniel G. Figueroa
2018-01-01
Full Text Available Real time evolution of classical gauge fields is relevant for a number of applications in particle physics and cosmology, ranging from the early Universe to dynamics of quark–gluon plasma. We present an explicit non-compact lattice formulation of the interaction between a shift-symmetric field and some U(1 gauge sector, a(xFμνF˜μν, reproducing the continuum limit to order O(dxμ2 and obeying the following properties: (i the system is gauge invariant and (ii shift symmetry is exact on the lattice. For this end we construct a definition of the topological number density K=FμνF˜μν that admits a lattice total derivative representation K=Δμ+Kμ, reproducing to order O(dxμ2 the continuum expression K=∂μKμ∝E→⋅B→. If we consider a homogeneous field a(x=a(t, the system can be mapped into an Abelian gauge theory with Hamiltonian containing a Chern–Simons term for the gauge fields. This allow us to study in an accompanying paper the real time dynamics of fermion number non-conservation (or chirality breaking in Abelian gauge theories at finite temperature. When a(x=a(x→,t is inhomogeneous, the set of lattice equations of motion do not admit however a simple explicit local solution (while preserving an O(dxμ2 accuracy. We discuss an iterative scheme allowing to overcome this difficulty.
Time evolution of linearized gauge field fluctuations on a real-time lattice
Energy Technology Data Exchange (ETDEWEB)
Kurkela, A. [CERN, Theoretical Physics Department, Geneva (Switzerland); University of Stavanger, Faculty of Science and Technology, Stavanger (Norway); Lappi, T. [University of Jyvaeskylae, Department of Physics, P.O. Box 35, Jyvaeskylae (Finland); University of Helsinki, Helsinki Institute of Physics, P.O. Box 64, Helsinki (Finland); Peuron, J. [University of Jyvaeskylae, Department of Physics, P.O. Box 35, Jyvaeskylae (Finland)
2016-12-15
Classical real-time lattice simulations play an important role in understanding non-equilibrium phenomena in gauge theories and are used in particular to model the prethermal evolution of heavy-ion collisions. Due to instabilities, small quantum fluctuations on top of the classical background may significantly affect the dynamics of the system. In this paper we argue for the need for a numerical calculation of a system of classical gauge fields and small linearized fluctuations in a way that keeps the separation between the two manifest. We derive and test an explicit algorithm to solve these equations on the lattice, maintaining gauge invariance and Gauss' law. (orig.)
Time evolution of linearized gauge field fluctuations on a real-time lattice
Kurkela, Aleksi; Peuron, Jarkko
2016-01-01
Classical real-time lattice simulations play an important role in understanding non-equilibrium phenomena in gauge theories and are used in particular to model the prethermal evolution of heavy-ion collisions. Due to instabilities, small quantum fluctuations on top of the classical background may significantly affect the dynamics of the system. In this paper we argue for the need for a numerical calculation of a system of classical gauge fields and small linearized fluctuations in a way that keeps the separation between the two manifest. We derive and test an explicit algorithm to solve these equations on the lattice, maintaining gauge invariance and Gauss's law.
Representation of a gauge field via intrinsic “BRST” operator
Energy Technology Data Exchange (ETDEWEB)
Batalin, Igor A., E-mail: batalin@lpi.ru [P.N. Lebedev Physical Institute, Leninsky Prospect 53, 119 991 Moscow (Russian Federation); Tomsk State Pedagogical University, Kievskaya St. 60, 634061 Tomsk (Russian Federation); Lavrov, Peter M., E-mail: lavrov@tspu.edu.ru [Tomsk State Pedagogical University, Kievskaya St. 60, 634061 Tomsk (Russian Federation); National Research Tomsk State University, Lenin Ave. 36, 634050 Tomsk (Russian Federation)
2015-11-12
We show that there exists a representation of a matrix-valued gauge field via intrinsic “BRST” operator assigned to matrix-valued generators of a gauge algebra. In this way, we reproduce the standard formulation of the ordinary Yang–Mills theory. In the case of a generating quasigroup/groupoid, we give a natural counterpart to the Yang–Mills action. The latter counterpart does also apply as to the most general case of an involution for matrix-valued gauge generators.
On the motion of matter in the geometrical gauge field theory
International Nuclear Information System (INIS)
Konopleva, N.P.
2005-01-01
In the geometrical gauge field theory, the motion equations of matter (elementary particles) are connected with the field equations. The problems arising from this connection are discussed. For the first time, such problems arose in Einstein's General Relativity. Einstein hoped that solution of these problems will allow explanation of elementary particles nature without making use of quantum mechanics. But, as it turned out, the situation is more difficult. Here the corresponding problems are formulated for the connection of equations of particle motion and field equations in the geometrical gauge field theory. It is shown that appearance of the problems under discussion is an inevitable effect of passage to relativism and local symmetries
Model of unified gauge fields; Le modele des champs de jauge unifies
Energy Technology Data Exchange (ETDEWEB)
Leite Lopes, J. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)
1998-04-01
In this work, we discuss the physical ideas which represents the basis for the unified gauge field model. Despite of the difficulties that we presently have for embodying in a natural manner muons and hadrons in that model, we have the feeling that we are on the way which seems to lead to the construction of a theory in which the Maxwell electromagnetic field and the Fermi weak interaction field are manifestations of a unique subjacent physical entity - the unified gauge fields. (author) 22 refs., 6 figs.
Recent developments in chiral gauge theories: approach of infinitely many fermi fields
International Nuclear Information System (INIS)
Narayanan, R.
1994-01-01
I present the recent developments in a specific sub-field of chiral gauge theories on the lattice. This subfield pertains to the use of infinitely many fermi fields to describe a single chiral field. In this approach, both anomalous and anomaly free theories can be discussed in equal footing. It produces the correct anomaly in the continuum limit. It has the potential to describe fermion number violating processes in the presence of a gauge field background with non-trivial topological charge on a finite lattice. (orig.)
Probing anomalous gauge boson couplings at LEP
International Nuclear Information System (INIS)
Dawson, S.; Valencia, G.
1994-01-01
We bound anomalous gauge boson couplings using LEP data for the Z → bar ∫∫ partial widths. We use an effective field theory formalism to compute the one-loop corrections resulting from non-standard model three and four gauge boson vertices. We find that measurements at LEP constrain the three gauge boson couplings at a level comparable to that obtainable at LEPII
Dupoyet, B.; Fiebig, H. R.; Musgrove, D. P.
2010-01-01
We report on initial studies of a quantum field theory defined on a lattice with multi-ladder geometry and the dilation group as a local gauge symmetry. The model is relevant in the cross-disciplinary area of econophysics. A corresponding proposal by Ilinski aimed at gauge modeling in non-equilibrium pricing is implemented in a numerical simulation. We arrive at a probability distribution of relative gains which matches the high frequency historical data of the NASDAQ stock exchange index.
Ground-state projection multigrid for propagators in 4-dimensional SU(2) gauge fields
International Nuclear Information System (INIS)
Kalkreuter, T.
1991-09-01
The ground-state projection multigrid method is studied for computations of slowly decaying bosonic propagators in 4-dimensional SU(2) lattice gauge theory. The defining eigenvalue equation for the restriction operator is solved exactly. Although the critical exponent z is not reduced in nontrivial gauge fields, multigrid still yields considerable speedup compared with conventional relaxation. Multigrid is also able to outperform the conjugate gradient algorithm. (orig.)
International Nuclear Information System (INIS)
Phillips, S.
1985-01-01
The mathematical problem of inverting the operator Δ x μν ≡ g μν g αβ δ x α δ x β -δ x μ δ x ν , as it arises in the path-integral quantization of an Abelian gauge theory, such as quantum electrodynamics, when no gauge-fixing Lagrangian field density is included, is studied in this article. Making use of the fact that the Schwinger source functions, which are introduced for the purpose of generating Green's functions, are free of divergence, a result that follows from the conversion of the exponentiated action into a Gaussian form, the apparently noninvertible partial differential equation, Δ x μν L ν (x) J μ (x), can, by the addition and subsequent subtraction of terms containing the divergence of the source function, be cast into a form that does possess a Green's function solution. The gauge-field propagator is the same as that obtained by the conventional technique, which involves gauge fixing when the gauge parameter, α, is set equal to one. Such an analysis suggests also that, provided the effect of fictitious particles that propagate only in closed loops are included for the study of Green's functions in non-Abelian gauge theories in Landau-type gauges, then, in quantizing either Abelian gauge theories or non-Abelian gauge theories in this generic kind of gauge, it is not necessary to add an explicit gauge-fixing term to the bilinear part of the gauge-field action
Spontaneous symmetry breaking in local gauge quantum field theory; the Higgs mechanism
International Nuclear Information System (INIS)
Strocchi, F.
1977-01-01
Spontaneous symmetry breakings in indefinite metric quantum field theories are analyzed and a generalization of the Goldstone theorem is proved. The case of local gauge quantum field theories is discussed in detail and a characterization is given of the occurrence of the Higgs mechanism versus the Goldstone mechanism. The Higgs phenomenon is explained on general grounds without the introduction of the so-called Higgs fields. The basic property is the relation between the local internal symmetry group and the local group of gauge transformations of the second kind. Spontaneous symmetry breaking of c-number gauge transformations of the second kind is shown to always occur if there are charged local fields. The implications about the absence of mass gap in the Wightman functions and the occurrence of massless particles associated with the unbroken generators in the Higgs phenomenon are discussed. (orig.) [de
Directory of Open Access Journals (Sweden)
Suhendro I.
2008-01-01
Full Text Available In this work, we attempt at constructing a comprehensive four-dimensional unified field theory of gravity, electromagnetism, and the non-Abelian Yang-Mills gauge field in which the gravitational, electromagnetic, and material spin fields are unified as intrinsic geometric objects of the space-time manifold $S_4$ via the connection, with the generalized non-Abelian Yang-Mills gauge field appearing in particular as a sub-field of the geometrized electromagnetic interaction.
International Nuclear Information System (INIS)
Rund, H.
1984-01-01
A certain class of geometric objects is considered against the background of a classical gauge field associated with an arbitrary structural Lie group. It is shown that the necessary and sufficient conditions for the invariance of the given objects under a finite gauge transformation are embodied in a set of three relations involving the derivatives of their components. As a special case these so-called invariance identities indicate that there cannot exist a gauge-invariant Lagrangian that depends on the gauge potentials, the interaction parameters, and the 4-velocity components of a test particle. However, the requirement that the equations of motion that result from such a lagrangian be gauge-invariant, uniquely determines the structure of these equations. (author)
Background field quantization in non-covariant gauges: Renormalization and WTST identities
International Nuclear Information System (INIS)
McKeon, G.; Phillips, S.B.; Samant, S.S.; Sherry, T.N.
1986-01-01
Background field quantization of pure YM theories in non-covariant gauges is treated with particular emphasis on renormalization. Gauge fixing terms of the form (1/2α)n . Qsup(a)fsup(ab)n . Qsup(b) are considered where fsup(ab) can assume the forms fsup(ab)sub((i))=-deltasup(ab) (the axial gauge), fsup(ab)sub((ii))=(n . D(A))sup(2ab)/n 4 and fsup(ab)sub((iii))=D 2 (A)sup(ab)/n 2 (the planar gauge). For the cases where fsup(ab) depends explicitly on the background field Asub(μ)sup(a) the ghost sector is enlarged by the addition of appropriate Nielson-Kallosh ghost fields. The BRS identities for these gauge choices are derived and solved. The quantum-corrected versions of both the bare background field gauge transformations and the bare quantum field gauge transformations are obtained from the BRS analysis. It is also shown that, to one loop, all the counter terms are determined by the background field independent part of the theory and this result is used, in cases (ii) and (iii), to derive all the counter terms and to show that Kallosh's theorem is verified. The result is also used to demonstrate the pathological nature of case (i) for αnot=0, in particular the result that Kallosh's theorem is not applicable. The result that the generating functional of Green functions is independent of the background field Asub(μ)sup(a) in the absence of all external sources is generalized to the case of non-covariant gauges. The equality established by Abbott between the 1PI generating functionals GAMMA tilde[A,0] and GAMMAsub(c)[anti Q; A] sub(anti Q=A), where GAMMAsub(c) is a conventional generating functional in an A-dependent gauge, is analysed. We show that the WTST identities satisfied by GAMMAsub(c) reduce, when anti Q is set equal to A, to the naive Ward-identity satisfied by GAMMA tilde[A,0]. (orig.)
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.
Geometro-stochastic quantization of gauge fields in curved space-time
International Nuclear Information System (INIS)
Prugovecki, E.
1988-01-01
It is shown that the geometro-stochastic method of quantization of massive fields in curved space-time can be extended to the massless cases of electromagnetic fields and general Yang-Mills fields. The Fock fibres of the massive case are replaced in the present context by fibres with indefinite inner products, such as Gupta-Bleuler fibres in the electromagnetic case. The quantum space-time form factor used in the massive case gives rise in the present case to quantum gauge frames whose elements are generalized coherent states corresponding to pseudounitary spin-one representations of direct products of the Poincare group with the U(1), SU(N) or other internal gauge groups. Quantum connections are introduced on bundles of second-quantized frames, and the corresponding parallel transport is expressed in terms of path integrals for quantum frame propagators. In the Yang-Mills case, these path integral make use of Faddeev-Popov quantum frames. It is shown, however, that in the present framework the ghost fields that give rise to these frames possess a geometric interpretation related to the presence of a super-gauge group that, in addition to the external Poincare and Yang-Mills gauge degrees of freedom, involves also the internal ones related to choices of gauge bases within the quantum fibres
International Nuclear Information System (INIS)
Power, B.D.; Priestland, C.R.D.
1978-01-01
This invention relates to vacuum gauges, particularly of the type known as Penning gauges, which are cold cathode ionisation gauges, in which a magnetic field is used to lengthen the electron path and thereby increase the number of ions produced. (author)
Novel symmetries in Weyl-invariant gravity with massive gauge field
Energy Technology Data Exchange (ETDEWEB)
Abhinav, K. [S.N. Bose National Centre for Basic Sciences, Salt Lake, Kolkata (India); Shukla, A.; Panigrahi, P.K. [Indian Institute of Science Education and Research Kolkata, Mohanpur (India)
2016-11-15
The background field method is used to linearize the Weyl-invariant scalar-tensor gravity, coupled with a Stueckelberg field. For a generic background metric, this action is found not to be invariant, under both a diffeomorphism and generalized Weyl symmetry, the latter being a combination of gauge and Weyl transformations. Interestingly, the quadratic Lagrangian, emerging from a background of Minkowski metric, respects both transformations independently. The Becchi-Rouet-Stora-Tyutin symmetry of scalar-tensor gravity coupled with a Stueckelberg-like massive gauge particle, possessing a diffeomorphism and generalized Weyl symmetry, reveals that in both cases negative-norm states with unphysical degrees of freedom do exist. We then show that, by combining diffeomorphism and generalized Weyl symmetries, all the ghost states decouple, thereby removing the unphysical redundancies of the theory. During this process, the scalar field does not represent any dynamic mode, yet modifies the usual harmonic gauge condition through non-minimal coupling with gravity. (orig.)
International Nuclear Information System (INIS)
Lee, B.W.
1976-01-01
Some introductory remarks to Yang-Mills fields are given and the problem of the Coulomb gauge is considered. The perturbation expansion for quantized gauge theories is discussed and a survey of renormalization schemes is made. The role of Ward-Takahashi identities in gauge theories is discussed. The author then discusses the renormalization of pure gauge theories and theories with spontaneously broken symmetry. (B.R.H.)
New approach to the problem of gauge field quantization
International Nuclear Information System (INIS)
Skachkov, N.B.; Shevchenko, O.Yu.
1987-01-01
A new scheme of calibration field quantization containing considerable change of the procedure of calibration conditions application on field variables is suggested. The above approach is based on a proved theorem on the subordination of fields to the additional Lorenz condition when applying a wide class of initial calibration conditions on these fields. This condition has the sense of the secondary bond, which must be included in the system of bonds during field quantization. The fact of secondary bond presence in the form of Lorenz condition was not earlier considered in literature and used in quantization. Due to this, the report suggests modification of all existing methods of field quantization: according to Dirac-Bergman, covariant approach using an indefinite metric and the method of functional integration
Gauge invariant Lagrangian formulation of massive higher spin fields in (A)dS3 space
International Nuclear Information System (INIS)
Buchbinder, I.L.; Snegirev, T.V.; Zinoviev, Yu.M.
2012-01-01
We develop the frame-like formulation of massive bosonic higher spin fields in the case of three-dimensional (A)dS space with the arbitrary cosmological constant. The formulation is based on gauge invariant description by involving the Stueckelberg auxiliary fields. The explicit form of the Lagrangians and the gauge transformation laws are found. The theory can be written in terms of gauge invariant objects similar to the massless theories, thus allowing us to hope to use the same methods for investigation of interactions. In the massive spin 3 field example we are able to rewrite the Lagrangian using the new the so-called separated variables, so that the study of Lagrangian formulation reduces to finding the Lagrangian containing only half of the fields. The same construction takes places for arbitrary integer spin field as well. Further working in terms of separated variables, we build Lagrangian for arbitrary integer spin and write it in terms of gauge invariant objects. Also, we demonstrate how to restore the full set of variables, thus receiving Lagrangian for the massive fields of arbitrary spin in the terms of initial fields.
Black-body radiation of noncommutative gauge fields
International Nuclear Information System (INIS)
Fatollahi, Amir H.; Hajirahimi, Maryam
2006-01-01
The black-body radiation is considered in a theory with noncommutative electRomegnetic fields; that is noncommutativity is introduced in field space, rather than in real space. A direct implication of the result on cosmic microwave background map is argued
Field-strength formulation of gauge theories. The Hamiltonian approach in the Abelian theory
International Nuclear Information System (INIS)
Mendel, E.; Durand, L.
1984-01-01
We develop a Hamiltonian approach to the field-strength or dual formation of the Abelian gauge theory in which the potential A/sup μ/ is eliminated as a dynamical variable. Our work is based on the covariant gauge x/sup μ/A/sub μ/(x) = 0 which allows a simple elimination of A/sup μ/ in terms of the field strengths F/sup munu/. We obtain complete results for the generating functional for the Green's functions of the theory, Z = Z[f,g], where f and g are nonlocal currents coupled to E and B, and illustrate some unfamiliar aspects of the new formalism
Problems of an external field in non-Abelian gauge theory
International Nuclear Information System (INIS)
Gavrilov, S.P.; Gitman, D.M.
1992-01-01
In the Abelian gauge field theory QED the principal problems connected with an external field are the problems of exact keeping of an external field in a perturbation theory and appearing in this case the peculiarities of the theory such as the instability of the vacuum and so on. There is the problem of an external field introduction or its interpretation side by side with this problem in Non-Abelian gauge theory. The solution of both these problems in Non-Abelian theory can be considered by analogy with QED. In the present paper, the authors discuss on the example of the spontaneously broken SU(2) x U(1) electroweak theory both the problems of an external field introduction and the problem of exact keeping of this field in the perturbation theory. The Langrangian of this theory in covariant gauge is chosen in the BRST invariant form. In spite of concrete character of the theory studied, the method can be extended to any gauge theory
Topological gravity from a transgression gauge field theory
International Nuclear Information System (INIS)
Merino, N.; Perez, A.; Salgado, P.; Valdivia, O.
2010-01-01
It is shown that a topological action for gravity in even dimensions can be obtained from a gravity theory whose Lagrangian is given by a transgression form invariant under the Poincare group. The field φ a , which is necessary to construct this type of topological gravity in even dimensions, is identified with the coset field associated with the non-linear realizations of the Poincare group ISO(d-1,1).
Dynamical chaos of non-Abelian gauge fields
International Nuclear Information System (INIS)
Matinyan, S.G.
1985-01-01
The review studies a special class of Yang--Mills fields: spatially homogeneous fields (classical Yang--Mills mechanics), which have no analog in linear Abelian electrodynamics. Computer and analytic approaches show that such fields possess dynamical stochasticity, on the basis of which it may be asserted that the classical Yang--Mills equations without external sources constitute a nonintegrable system. The Higgs mechanism eliminates this stochasticity, and at a certain value of the vacuum expectation of the scalar field there is a phase transition of the disorder-order (confinement-deconfinement) type. The system with external sources apparently behaves similarly. The connection between this stochasticity and the mechanism of dimensional reduction in macroscopic systems and with the color-confinement phenomenon is considered. It is shown that the presence in the vacuum of random (Gaussian) currents leads to confinement of the fields generated by these currents. Attention is drawn to the possible manifestation of the stochasticity of the classical fields in multiparticle hadron-production processes. Such manifestation reflects universal stochastic features characteristic of systems of very different natures (statistics of the counting of thermoelectrons from random sources and photoelectrons from laser radiation that passes through a liquid in the critical state, developed turbulence in hydrodynamics, stellar systems, and KNO scaling in multiparticle production)
Supersymmetric gauged double field theory: systematic derivation by virtue of twist
International Nuclear Information System (INIS)
Cho, Wonyoung; Fernández-Melgarejo, J.J.; Jeon, Imtak; Park, Jeong-Hyuck
2015-01-01
In a completely systematic and geometric way, we derive maximal and half-maximal supersymmetric gauged double field theories in lower than ten dimensions. To this end, we apply a simple twisting ansatz to the D=10 ungauged maximal and half-maximal supersymmetric double field theories constructed previously within the so-called semi-covariant formalism. The twisting ansatz may not satisfy the section condition. Nonetheless, all the features of the semi-covariant formalism, including its complete covariantizability, are still valid after the twist under alternative consistency conditions. The twist allows gaugings as supersymmetry preserving deformations of the D=10 untwisted theories after Scherk-Schwarz-type dimensional reductions. The maximal supersymmetric twist requires an extra condition to ensure both the Ramond-Ramond gauge symmetry and the 32 supersymmetries unbroken.
Gauge-invariant scalar and field strength correlators in 3d
Laine, Mikko
1998-01-01
Gauge-invariant non-local scalar and field strength operators have been argued to have significance, e.g., as a way to determine the behaviour of the screened static potential at large distances, as order parameters for confinement, as input parameters in models of confinement, and as gauge-invariant definitions of light constituent masses in bound state systems. We measure such "correlators" in the 3d pure SU(2) and SU(2)+Higgs models on the lattice. We extract the corresponding mass parameters and discuss their scaling and physical interpretation. We find that the finite part of the MS-bar scheme mass measured from the field strength correlator is large, more than half the glueball mass. We also determine the non-perturbative contribution to the Debye mass in the 4d finite T SU(2) gauge theory with a method due to Arnold and Yaffe, finding $\\delta m_D\\approx 1.06(4)g^2T$.
Gravitational waves from Abelian gauge fields and cosmic strings at preheating
International Nuclear Information System (INIS)
Dufaux, Jean-Francois; Figueroa, Daniel G.; Garcia-Bellido, Juan
2010-01-01
Primordial gravitational waves provide a very important stochastic background that could be detected soon with interferometric gravitational wave antennas or indirectly via the induced patterns in the polarization anisotropies of the cosmic microwave background. The detection of these waves will open a new window into the early Universe, and therefore it is important to characterize in detail all possible sources of primordial gravitational waves. In this paper we develop theoretical and numerical methods to study the production of gravitational waves from out-of-equilibrium gauge fields at preheating. We then consider models of preheating after hybrid inflation, where the symmetry breaking field is charged under a local U(1) symmetry. We analyze in detail the dynamics of the system in both momentum and configuration space. We show that gauge fields leave specific imprints in the resulting gravitational wave spectra, mainly through the appearance of new peaks at characteristic frequencies that are related to the mass scales in the problem. We also show how these new features in the spectra correlate with stringlike spatial configurations in both the Higgs and gauge fields that arise due to the appearance of topological winding numbers of the Higgs around Nielsen-Olesen strings. We study in detail the time evolution of the spectrum of gauge fields and gravitational waves as these strings evolve and decay before entering a turbulent regime where the gravitational wave energy density saturates.
Constrained optimization for position calibration of an NMR field camera.
Chang, Paul; Nassirpour, Sahar; Eschelbach, Martin; Scheffler, Klaus; Henning, Anke
2018-07-01
Knowledge of the positions of field probes in an NMR field camera is necessary for monitoring the B 0 field. The typical method of estimating these positions is by switching the gradients with known strengths and calculating the positions using the phases of the FIDs. We investigated improving the accuracy of estimating the probe positions and analyzed the effect of inaccurate estimations on field monitoring. The field probe positions were estimated by 1) assuming ideal gradient fields, 2) using measured gradient fields (including nonlinearities), and 3) using measured gradient fields with relative position constraints. The fields measured with the NMR field camera were compared to fields acquired using a dual-echo gradient recalled echo B 0 mapping sequence. Comparisons were done for shim fields from second- to fourth-order shim terms. The position estimation was the most accurate when relative position constraints were used in conjunction with measured (nonlinear) gradient fields. The effect of more accurate position estimates was seen when compared to fields measured using a B 0 mapping sequence (up to 10%-15% more accurate for some shim fields). The models acquired from the field camera are sensitive to noise due to the low number of spatial sample points. Position estimation of field probes in an NMR camera can be improved using relative position constraints and nonlinear gradient fields. Magn Reson Med 80:380-390, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.
Supersymmetry for gauged double field theory and generalised Scherk–Schwarz reductions
International Nuclear Information System (INIS)
Berman, David S.; Lee, Kanghoon
2014-01-01
Previous constructions of supersymmetry for double field theory have relied on the so-called strong constraint. In this paper, the strong constraint is relaxed and the theory is shown to possess supersymmetry once the generalised Scherk–Schwarz reduction is imposed. The equivalence between the generalised Scherk–Schwarz reduced theory and the gauged double field theory is then examined in detail for the supersymmetric theory. As a biproduct we write the generalised Killing spinor equations for the supersymmetric double field theory
Relations between correlation functions in gauge field theory
International Nuclear Information System (INIS)
Simonov, Yu. A.; Shevchenko, V. I.
1997-01-01
Exact relations between vacuum correlations of non-Abelian field strengths are obtained. With the aid of exterior differentiation, the invariant parts of a given correlation function are expressed in terms of higher order correlation functions. The corollaries of these relations for the behavior of nonperturbative correlation functions at small and large distances are deduced
Roy, Sthitadhi; Kolodrubetz, Michael; Goldman, Nathan; Grushin, Adolfo G.
2018-04-01
In this work, we describe a toolbox to realize and probe synthetic axial gauge fields in engineered Weyl semimetals. These synthetic electromagnetic fields, which are sensitive to the chirality associated with Weyl nodes, emerge due to spatially and temporally dependent shifts of the corresponding Weyl momenta. First, we introduce two realistic models, inspired by recent cold-atom developments, which are particularly suitable for the exploration of these synthetic axial gauge fields. Second, we describe how to realize and measure the effects of such axial fields through center-of-mass observables, based on semiclassical equations of motion and exact numerical simulations. In particular, we suggest realistic protocols to reveal an axial Hall response due to the axial electric field \
On the principle of gauge invariance in the field theory with curved momentum space
International Nuclear Information System (INIS)
Mir-Kasimov, R.M.
1990-11-01
The gauge transformations consistent with the hypothesis of the curved momentum space are considered. In this case the components of the electromagnetic field are not commuting. The finite-difference analogue of the D'Alambert equation is derived. (author). 5 refs
Static, self-dual, finite action SU(3) gauge fields in the de Sitter space
International Nuclear Information System (INIS)
Chakrabarti, A.; Comtet, A.; Viswanathan, K.S.; Simon Fraser Univ., Burnaby, British Columbia
1980-01-01
Static, self-dual, finite action SU(3) gauge fields are constructed on the euclidean section of the positive curvature de Sitter metric with periodic time. Their relation to known time dependent flat space solutions is pointed out. Their significances and possible applications are indicated. (orig.)
Construction of quantized gauge fields: continuum limit of the Abelian Higgs model in two dimensions
International Nuclear Information System (INIS)
Seiler, E.
1981-01-01
The author proves the existence of the continuum limit of the two-dimensional Higgs model for two cases: External gauge fields that are Hoelder continuous and may be non-Abelian, and the fully quantized Abelian model. In the latter case all Wightman axioms are verified except clustering. Important ingredients are a universal diamagnetic bound and correlation inequalities. (Auth.)
Some physical solutions of Yang's equations for SU (2) gauge fields ...
Indian Academy of Sciences (India)
Some previously obtained physical solutions [1–3] of Yang's equations for (2) gauge fields [4], Charap's equations for pion dynamics [5,6] and their combination as proposed by Chakraborty and Chanda [1] have been presented. They represent different physical characteristics, e.g. spreading wave with solitary profile ...
'Symmetry dictates interaction'. For the jubilee of the non-abelian gauge fields
International Nuclear Information System (INIS)
Li Huazhong
2004-01-01
The article is written for the Jubilee, 50 years after the birth of non-abelian gauge field theory which was proposed by C.N. yang and R. Mills in 1954. The main ideas initiated in the paper and great influences are briefly outlined
International Nuclear Information System (INIS)
Aquino, V.M. de.
1987-01-01
We have analysed, within a semi classical approach, the influence of external electromagnetic field on phase transitions in gauge theories. The critical temperature was calculated for an Abelian case, scalar electrodynamics, and for an non Abelian case, the Weinberg Salam model. (author)
Geometrical phases from global gauge invariance of nonlinear classical field theories
International Nuclear Information System (INIS)
Garrison, J.C.; Chiao, R.Y.
1988-01-01
We show that the geometrical phases recently discovered in quantum mechanics also occur naturally in the theory of any classical complex multicomponent field satisfying nonlinear equations derived from a Lagrangean with is invariant under gauge transformations of the first kind. Some examples are the paraxial wave equation for nonlinear optics, and Ginzburg-Landau equations for complex order parameters in condensed-matter physics
N=2, 4 supersymmetric gauge field theory in two-time physics
International Nuclear Information System (INIS)
Bars, Itzhak; Kuo, Y.-C.
2009-01-01
In the context of two-time physics in 4+2 dimensions we construct the most general N=2, 4 supersymmetric Yang-Mills gauge theories for any gauge group G. This builds on our previous work for N=1 supersymmetry (SUSY). The action, the conserved SUSY currents, and the SU(N) covariant SUSY transformation laws are presented for both N=2 and N=4. When the equations of motion are used the SUSY transformations close to the supergroup SU(2,2|N) with N=1, 2, 4. The SU(2,2)=SO(4,2) subsymmetry is realized linearly on 4+2 dimensional flat spacetime. All fields, including vectors and spinors, are in 4+2 dimensions. The extra gauge symmetries in 2T field theory, together with the kinematic constraints that follow from the action, remove all the ghosts to give a unitary theory. By choosing gauges and solving the kinematic equations, the 2T field theory in 4+2 flat spacetime can be reduced to various shadows in various 3+1 dimensional (generally curved) spacetimes. These shadows are related to each other by dualities. The conformal shadows of our theories in flat 3+1 dimensions coincide with the well known counterpart N=1, 2, 4 supersymmetric massless renormalizable field theories in 3+1 dimensions. It is expected that our more symmetric new structures in 4+2 spacetime may be useful for nonperturbative or exact solutions of these theories.
Loop calculations for the non-commutative U*(1) gauge field model with oscillator term
International Nuclear Information System (INIS)
Blaschke, Daniel N.; Grosse, Harald; Kronberger, Erwin; Schweda, Manfred; Wohlgenannt, Michael
2010-01-01
Motivated by the success of the non-commutative scalar Grosse-Wulkenhaar model, a non-commutative U * (1) gauge field theory including an oscillator-like term in the action has been put forward in (Blaschke et al. in Europhys. Lett. 79:61002, 2007). The aim of the current work is to analyze whether that action can lead to a fully renormalizable gauge model on non-commutative Euclidean space. In a first step, explicit one-loop graph computations are hence presented, and their results as well as necessary modifications of the action are successively discussed. (orig.)
International Nuclear Information System (INIS)
Wu Ning; Zhang Dahua
2007-01-01
A systematic method is developed to study the classical motion of a mass point in gravitational gauge field. First, by using Mathematica, a spherical symmetric solution of the field equation of gravitational gauge field is obtained, which is just the traditional Schwarzschild solution. Combining the principle of gauge covariance and Newton's second law of motion, the equation of motion of a mass point in gravitational field is deduced. Based on the spherical symmetric solution of the field equation and the equation of motion of a mass point in gravitational field, we can discuss classical tests of gauge theory of gravity, including the deflection of light by the sun, the precession of the perihelia of the orbits of the inner planets and the time delay of radar echoes passing the sun. It is found that the theoretical predictions of these classical tests given by gauge theory of gravity are completely the same as those given by general relativity.
Dynamical mechanism of symmetry breaking and particle mass generation in gauge field theories
International Nuclear Information System (INIS)
Miranskij, V.A.; Fomin, P.I.
1985-01-01
The dynamics of the spotaneous symmetry breaking and the particle mass generation in gauge theories with no fundamental scalar fields is considered. The emphasis is on the consideration of the symmetry breaking mechanism connected with the dynamics of the supercritical Coulomb-like forces caused by the gauge boson exchange between fermions. This mechanism is applied to different gauge theories, in particular, to the description of the spontaneous chira symmetry breaking in quantum chromodynamics. The mass relations for pseudoscalar meson nonet are obtained and it is shown that this mechanism resuls in the dynamical realisation of the hypothesis of the partial conservation of the axial-vector currents. The qualitative description of scalar mesons is given. The nature of the ultraviolet divergencies in quantum electrodynamics (QED) is investigated from the viewpoint of the dynamics of the fermion mass generation. The mechanism of the appearance of the additional (in comparison with perturbation theory) ultraviolet divergencies in QED with large bare coupling constant is indicated. The physical phenomenon underlying this mechanism is identified as the field theory analogue of the quantum mechanical ''fall into the centre'' (collapse) phenomenon. The similr phenomenon is shown to take place in some two-dimensional quantum field models. The dynamics of the bifermion condensates formation in tumblin gauge theories is briefly discussed
Restoration of the covariant gauge α in the initial field of gravity in de Sitter spacetime
Energy Technology Data Exchange (ETDEWEB)
Cheong, Lee Yen; Yan, Chew Xiao [Department of Fundamental and Applied Sciences, Universiti Teknologi Petronas, Bandar Seri Iskandar, Tronoh 31750, Perak (Malaysia)
2014-03-05
The gravitational field generated by a mass term and the initial surface through covariant retarded Green's function for linearized gravity in de Sitter spacetime was studied recently [4, 5] with the covariant gauges set to β = 2/3 and α = 5/3. In this paper we extend the work to restore the gauge parameter α in the field coming from the initial data using the method of shifting the parameter. The α terms in the initial field cancels exactly with the one coming from the source term. Consequently, the correct field configuration, with two equal mass points moving in its geodesic, one located at the North pole and another one located at the South pole, is reproduced in the whole manifold of de Sitter spacetime.
On the Motion of Matter in the Geometrical Gauge Field Theory
Konopleva, N P
2005-01-01
In the geometrical gauge field theory, the motion equations of matter (elementary particles) are connected with the field equations. In the talk, the problems arising from this connection are discussed. For the first time, such problems arose in Einstein's General Relativity. Einstein hoped that solution of these problems will allow explanation of elementary particles nature without making use of quantum mechanics. But, as it turned out, the situation is more difficult. Here the corresponding problems are formulated for the connection of equations of particle motion and field equations in the geometrical gauge field theory. It is shown that appearance of the problems under discussion is an inevitable effect of passage to relativism and local symmetries.
Pure gauge configurations and solutions to fermionic superstring field theory equations of motion
International Nuclear Information System (INIS)
Aref'eva, I Ya; Gorbachev, R V; Medvedev, P B
2009-01-01
Recent results on solutions to the equation of motion of the cubic fermionic string field theory and an equivalence of nonpolynomial and cubic string field theory are discussed. To have the possibility of dealing with both GSO(+) and GSO(-) sectors in the uniform way, a matrix formulation for the NS fermionic SFT is used. In constructions of analytical solutions to open-string field theories truncated pure gauge configurations parametrized by wedge states play an essential role. The matrix form of this parametrization for NS fermionic SFT is presented. Using the cubic open superstring field theory as an example we demonstrate explicitly that for the large parameter of the perturbation expansion these truncated pure gauge configurations give divergent contributions to the equations of motion on the subspace of the wedge states. The perturbation expansion is corrected by adding extra terms that are just those necessary for the equation of motion contracted with the solution itself to be satisfied.
International Nuclear Information System (INIS)
Jing Sicong; Ruan Jie; AH. Dept. of Modern Physics)
1990-01-01
The perturbation theory in coset pure gauge field theory is studied for the first time. By using the Bjorken-johnson-Low technique and calculating the Schwinger term in related commutators, the anomalous Ward identity in Abelian coset pure gauge field theory is derived, which is consistent with the non-perutrbative calculation
On a gauge theory of the self-dual field and its quantization
International Nuclear Information System (INIS)
Srivastava, P.P.
1990-01-01
A gauge theory of self-dual fields is constructed by adding a Wess-Zumino term to the recently studied formulation based on a second-order scalar field lagrangian carrying with it an auxiliary vector field to take care of the self-duality constraint in a linear fashion. The two versions are quantized using the BRST formulation following the BFV procedure. No violation of microcausality occurs and the action of the ordinary scalar field may not be written as the sum of the actions of the self- and anti-self-dual fields. (orig.)
Superconformal quantum field theories in string. Gauge theory dualities
Energy Technology Data Exchange (ETDEWEB)
Wiegandt, Konstantin
2012-08-14
In this thesis aspects of superconformal field theories that are of interest in the so-called AdS/CFT correspondence are investigated. The AdS/CFT correspondence states a duality between string theories living on Anti-de Sitter space and superconformal quantum field theories in Minkowski space. In the context of the AdS/CFT correspondence the so-called Wilson loop/amplitude duality was discovered, stating the equality of the finite parts of n-gluon MHV amplitudes and n-sided lightlike polygonal Wilson loops in N=4 supersymmetric Yang-Mills (SYM) theory. It is the subject of the first part of this thesis to investigate the Wilson loop side of a possible similar duality in N=6 superconformal Chern-Simons matter (ABJM) theory. The main result is, that the expectation value of n-sided lightlike polygonal Wilson loops vanishes at one-loop order and at two-loop order is identical in its functional form to the Wilson loop in N=4 SYM theory at one-loop order. Furthermore, an anomalous conformal Ward identity for Wilson loops in Chern-Simons theory is derived. Related developments and symmetries of amplitudes and correlators in ABJM theory are discussed as well. In the second part of this thesis we calculate three-point functions of two protected operators and one twist-two operator with arbitrary even spin j in N=4 SYM theory. In order to carry out the calculations, the indices of the spin j operator are projected to the light-cone and the correlator is evaluated in a soft-limit where the momentum coming in at the spin j operator becomes zero. This limit largely simplifies the perturbative calculation, since all three-point diagrams effectively reduce to two-point diagrams and the dependence on the one-loop mixing matrix drops out completely. The result is in agreement with the analysis of the operator product expansion of four-point functions of half-BPS operators by Dolan and Osborn in 2004.
Superconformal quantum field theories in string. Gauge theory dualities
International Nuclear Information System (INIS)
Wiegandt, Konstantin
2012-01-01
In this thesis aspects of superconformal field theories that are of interest in the so-called AdS/CFT correspondence are investigated. The AdS/CFT correspondence states a duality between string theories living on Anti-de Sitter space and superconformal quantum field theories in Minkowski space. In the context of the AdS/CFT correspondence the so-called Wilson loop/amplitude duality was discovered, stating the equality of the finite parts of n-gluon MHV amplitudes and n-sided lightlike polygonal Wilson loops in N=4 supersymmetric Yang-Mills (SYM) theory. It is the subject of the first part of this thesis to investigate the Wilson loop side of a possible similar duality in N=6 superconformal Chern-Simons matter (ABJM) theory. The main result is, that the expectation value of n-sided lightlike polygonal Wilson loops vanishes at one-loop order and at two-loop order is identical in its functional form to the Wilson loop in N=4 SYM theory at one-loop order. Furthermore, an anomalous conformal Ward identity for Wilson loops in Chern-Simons theory is derived. Related developments and symmetries of amplitudes and correlators in ABJM theory are discussed as well. In the second part of this thesis we calculate three-point functions of two protected operators and one twist-two operator with arbitrary even spin j in N=4 SYM theory. In order to carry out the calculations, the indices of the spin j operator are projected to the light-cone and the correlator is evaluated in a soft-limit where the momentum coming in at the spin j operator becomes zero. This limit largely simplifies the perturbative calculation, since all three-point diagrams effectively reduce to two-point diagrams and the dependence on the one-loop mixing matrix drops out completely. The result is in agreement with the analysis of the operator product expansion of four-point functions of half-BPS operators by Dolan and Osborn in 2004.
Mean field theory for non-abelian gauge theories and fluid dynamics. A brief progress report
International Nuclear Information System (INIS)
Wadia, Spenta R.
2009-01-01
We review the long standing problem of 'mean field theory' for non-abelian gauge theories. As a consequence of the AdS/CFT correspondence, in the large N limit, at strong coupling, and high temperatures and density, the 'mean field theory' is described by the Navier-Stokes equations of fluid dynamics. We also discuss and present results on the non-conformal fluid dynamics of the D1 brane in 1+1 dim. (author)
Pair production in an electric field in a time-dependent gauge
International Nuclear Information System (INIS)
Barut, A.O.; Duru, I.H.
1989-07-01
A new nonperturbative method of calculation of the pair production in a constant electric field is presented in which the propagator is evaluated entirely by path-integration in a time-dependent potential. This gauge and the path integration correctly define all the normalizations. As a by-product we get also the Unruh formula since the constant electric field provides an accelerated frame. (author). 11 refs
Valley-polarized quantum transport generated by gauge fields in graphene
DEFF Research Database (Denmark)
Settnes, Mikkel; Garcia, Jose H; Roche, Stephan
2017-01-01
We report on the possibility to simultaneously generate in graphene a bulk valley-polarized dissipative transport and a quantum valley Hall effect by combining strain-induced gauge fields and real magnetic fields. Such unique phenomenon results from a ‘resonance/anti-resonance’ effect driven by t...... Kubo transport methods combined with a valley projection scheme to access valley-dependent conductivities and show that the results are robust against disorder....
Gauge anomaly with vector and axial-vector fields in 6D curved space
Yajima, Satoshi; Eguchi, Kohei; Fukuda, Makoto; Oka, Tomonori
2018-03-01
Imposing the conservation equation of the vector current for a fermion of spin 1/2 at the quantum level, a gauge anomaly for the fermion coupling with non-Abelian vector and axial-vector fields in 6D curved space is expressed in tensorial form. The anomaly consists of terms that resemble the chiral U(1) anomaly and the commutator terms that disappear if the axial-vector field is Abelian.
Introduction to gauge theories
International Nuclear Information System (INIS)
Wit, B. de
1983-01-01
In these lectures we present the key ingredients of theories with local gauge invariance. We introduce gauge invariance as a starting point for the construction of a certain class of field theories, both for abelian and nonabelian gauge groups. General implications of gauge invariance are discussed, and we outline in detail how gauge fields can acquire masses in a spontaneous fashion. (orig./HSI)
Emergent Gauge Fields and Their Nonperturbative Effects in Correlated Electrons
Kim, Ki-Seok; Tanaka, Akihiro
dynamics of topological excitations is again seen to be crucial in classifying topologically nontrivial gapped systems. We point to some hidden links between several effective field theories with topological terms, starting with one dimensional physics, and subsequently finding natural generalizations to higher dimensions.
Entropy Bounds for Constrained Two-Dimensional Fields
DEFF Research Database (Denmark)
Forchhammer, Søren Otto; Justesen, Jørn
1999-01-01
The maximum entropy and thereby the capacity of 2-D fields given by certain constraints on configurations are considered. Upper and lower bounds are derived.......The maximum entropy and thereby the capacity of 2-D fields given by certain constraints on configurations are considered. Upper and lower bounds are derived....
The first law of black hole mechanics for fields with internal gauge freedom
International Nuclear Information System (INIS)
Prabhu, Kartik
2017-01-01
We derive the first law of black hole mechanics for physical theories based on a local, covariant and gauge-invariant Lagrangian where the dynamical fields transform non-trivially under the action of some internal gauge transformations. The theories of interest include General Relativity formulated in terms of tetrads, Einstein–Yang–Mills theory and Einstein–Dirac theory. Since the dynamical fields of these theories have some internal gauge freedom, we argue that there is no natural group action of diffeomorphisms of spacetime on such dynamical fields. In general, such fields cannot even be represented as smooth, globally well-defined tensor fields on spacetime. Consequently the derivation of the first law by Iyer and Wald cannot be used directly. Nevertheless, we show how such theories can be formulated on a principal bundle and that there is a natural action of automorphisms of the bundle on the fields. These bundle automorphisms encode both spacetime diffeomorphisms and internal gauge transformations. Using this reformulation we define the Noether charge associated to an infinitesimal automorphism and the corresponding notion of stationarity and axisymmetry of the dynamical fields. We first show that we can define certain potentials and charges at the horizon of a black hole so that the potentials are constant on the bifurcate Killing horizon, giving a generalised zeroth law for bifurcate Killing horizons. We further identify the gravitational potential and perturbed charge as the temperature and perturbed entropy of the black hole which gives an explicit formula for the perturbed entropy analogous to the Wald entropy formula. We then obtain a general first law of black hole mechanics for such theories. The first law relates the perturbed Hamiltonians at spatial infinity and the horizon, and the horizon contributions take the form of a ‘potential times perturbed charge’ term. We also comment on the ambiguities in defining a prescription for the total
Constraining brane inflationary magnetic field from cosmoparticle physics after Planck
International Nuclear Information System (INIS)
Choudhury, Sayantan
2015-01-01
In this article, I have studied the cosmological and particle physics constraints on a generic class of large field (|Δϕ|>M_p) and small field (|Δϕ|< M_p) models of brane inflationary magnetic field from: (1) tensor-to-scalar ratio (r), (2) reheating, (3) leptogenesis and (4) baryogenesis in case of Randall-Sundrum single braneworld gravity (RSII) framework. I also establish a direct connection between the magnetic field at the present epoch (B_0) and primordial gravity waves (r), which give a precise estimate of non-vanishing CP asymmetry (ϵ_C_P) in leptogenesis and baryon asymmetry (η_B) in baryogenesis scenario respectively. Further assuming the conformal invariance to be restored after inflation in the framework of RSII, I have explicitly shown that the requirement of the sub-dominant feature of large scale coherent magnetic field after inflation gives two fold non-trivial characteristic constraints- on equation of state parameter (w) and the corresponding energy scale during reheating (ρ_r_h"1"/"4) epoch. Hence giving the proposal for avoiding the contribution of back-reaction from the magnetic field I have established a bound on the generic reheating characteristic parameter (R_r_h) and its rescaled version (R_s_c), to achieve large scale magnetic field within the prescribed setup and further apply the CMB constraints as obtained from recently observed Planck 2015 data and Planck+BICEP2+Keck Array joint constraints. Using all these derived results I have shown that it is possible to put further stringent constraints on various classes of large and small field inflationary models to break the degeneracy between various cosmological parameters within the framework of RSII. Finally, I have studied the consequences from two specific models of brane inflation- monomial and hilltop, after applying the constraints obtained from inflation and primordial magnetic field.
Gravity/Fluid Correspondence and Its Application on Bulk Gravity with U(1) Gauge Field
International Nuclear Information System (INIS)
Hu, Ya-Peng; Zhang, Jian-Hui
2014-01-01
As the long wavelength limit of the AdS/CFT correspondence, the gravity/fluid correspondence has been shown to be a useful tool for extracting properties of the fluid on the boundary dual to the gravity in the bulk. In this paper, after briefly reviewing the algorithm of gravity/fluid correspondence, we discuss the results of its application on bulk gravity with a U(1) gauge field. In the presence of a U(1) gauge field, the dual fluid possesses more interesting properties such as its charge current. Furthermore, an external field A_μ"e"x"t could affect the charge current, and the U(1) Chern-Simons term also induces extra structures to the dual current giving anomalous transport coefficients.
Valley-polarized quantum transport generated by gauge fields in graphene
Settnes, Mikkel; Garcia, Jose H.; Roche, Stephan
2017-09-01
We report on the possibility to simultaneously generate in graphene a bulk valley-polarized dissipative transport and a quantum valley Hall effect by combining strain-induced gauge fields and real magnetic fields. Such unique phenomenon results from a ‘resonance/anti-resonance’ effect driven by the superposition/cancellation of superimposed gauge fields which differently affect time reversal symmetry. The onset of a valley-polarized Hall current concomitant to a dissipative valley-polarized current flow in the opposite valley is revealed by a {{e}2}/h Hall conductivity plateau. We employ efficient linear scaling Kubo transport methods combined with a valley projection scheme to access valley-dependent conductivities and show that the results are robust against disorder.
Confining gauge theories and holographic entanglement entropy with a magnetic field
Energy Technology Data Exchange (ETDEWEB)
Dudal, David [KU Leuven Campus Kortrijk - KULAK, Department of Physics,Etienne Sabbelaan 51 bus 7800, Kortrijk, 8500 (Belgium); Ghent University, Department of Physics and Astronomy,Krijgslaan 281-S9, Gent, 9000 (Belgium); Mahapatra, Subhash [KU Leuven Campus Kortrijk - KULAK, Department of Physics,Etienne Sabbelaan 51 bus 7800, Kortrijk, 8500 (Belgium)
2017-04-06
We consider the soft wall model for a heuristic holographical modelling of a confining gauge theory and discuss how the introduction of a (constant) magnetic field influences the (de)confinement phase structure. We use the entanglement entropy as a diagnostic tool in terms of the length of an entangling strip geometry. Due to the anisotropy introduced by the magnetic field, we find that the results depend on the orientation of the strip relative to the field. This allows to identify a richer, anisotropic, interplay between confinement and a magnetic field than possibly can be extracted from a more standard order parameter as, for example, the Polyakov loop expectation value.
Endogenous Cortical Oscillations Constrain Neuromodulation by Weak Electric Fields
Schmidt, Stephen L.; Iyengar, Apoorva K.; Foulser, A. Alban; Boyle, Michael R.; Fröhlich, Flavio
2014-01-01
Background Transcranial alternating current stimulation (tACS) is a non-invasive brain stimulation modality that may modulate cognition by enhancing endogenous neocortical oscillations with the application of sine-wave electric fields. Yet, the role of endogenous network activity in enabling and shaping the effects of tACS has remained unclear. Objective We combined optogenetic stimulation and multichannel slice electrophysiology to elucidate how the effect of weak sine-wave electric field depends on the ongoing cortical oscillatory activity. We hypothesized that the structure of the response to stimulation depended on matching the stimulation frequency to the endogenous cortical oscillation. Methods We studied the effect of weak sine-wave electric fields on oscillatory activity in mouse neocortical slices. Optogenetic control of the network activity enabled the generation of in vivo like cortical oscillations for studying the temporal relationship between network activity and sine-wave electric field stimulation. Results Weak electric fields enhanced endogenous oscillations but failed to induce a frequency shift of the ongoing oscillation for stimulation frequencies that were not matched to the endogenous oscillation. This constraint on the effect of electric field stimulation imposed by endogenous network dynamics was limited to the case of weak electric fields targeting in vivo-like network dynamics. Together, these results suggest that the key mechanism of tACS may be enhancing but not overriding of intrinsic network dynamics. Conclusion Our results contribute to understanding the inconsistent tACS results from human studies and propose that stimulation precisely adjusted in frequency to the endogenous oscillations is key to rational design of non-invasive brain stimulation paradigms. PMID:25129402
Indian Academy of Sciences (India)
Here it has been found that the real form of Yang's self-dual equations [2,3] passes the Painlevé test for integrability in the sense of Weiss et al [4] and admit truncation of series leading to non-trivial exact solutions obtained previously and auto-Backlund transformation between two pairs of these solutions (see for example.
Spin dynamics under local gauge fields in chiral spin-orbit coupling systems
International Nuclear Information System (INIS)
Tan, S.G.; Jalil, M.B.A.; Fujita, T.; Liu, X.J.
2011-01-01
Research highlights: → We derive a modified LLG equation in magnetic systems with spin-orbit coupling (SOC). → Our results are applied to magnetic multilayers, and DMS and magnetic Rashba systems. → SOC mediated magnetization switching is predicted in rare earth metals (large SOC). → The magnetization trajectory and frequency can be modulated by applied voltage. → This facilitates potential application as tunable microwave oscillators. - Abstract: We present a theoretical description of local spin dynamics in magnetic systems with a chiral spin texture and finite spin-orbit coupling (SOC). Spin precession about the relativistic effective magnetic field in a SOC system gives rise to a non-Abelian SU(2) gauge field reminiscent of the Yang-Mills field. In addition, the adiabatic relaxation of electron spin along the local spin yields an U(1) x U(1) topological gauge (Berry) field. We derive the corresponding equation of motion i.e. modified Landau-Lifshitz-Gilbert (LLG) equation, for the local spin under the influence of these effects. Focusing on the SU(2) gauge, we obtain the spin torque magnitude, and the amplitude and frequency of spin oscillations in this system. Our theoretical estimates indicate significant spin torque and oscillations in systems with large spin-orbit coupling, which may be utilized in technological applications such as current-induced magnetization-switching and tunable microwave oscillators.
Constrained deterministic leader-follower mean field control
Möller, L.; Gentile, B.; Parise, F.; Grammatico, S.; Lygeros, J.
2016-01-01
We consider a mean field game among a large population of noncooperative agents divided into two categories: leaders and followers. Each agent is subject to heterogeneous convex constraints and minimizes a quadratic cost function; the cost of each leader is affected by the leaders' aggregate
International Nuclear Information System (INIS)
Sharma, P.; Zhang, X.
2006-01-01
The failure of classical elasticity to address dislocation behavior spatially close to its core and (in Lorentz-type fashion) near the speed of sound is well known. In gauge field theory of defects, the latter are not postulated a priori in an ad hoc fashion rather defects such as dislocations arise naturally as a consequence of broken translational symmetry exhibiting solutions that are physically meaningful (e.g., removal of divergence of stress and the natural emergence of a core making redundant the artificial cut-off radius). In the present work we present the gauge field theoretic solution to the problem of a uniformly moving screw dislocation. Apart from the formal derivations, we show that stress divergence at the core of the dislocation is removed at all time and (consistent with atomistic simulations), supersonic states are found to be admissible
Localizing gauge fields on a topological Abelian string and the Coulomb law
International Nuclear Information System (INIS)
Torrealba S, Rafael S.
2010-01-01
The confinement of electromagnetic field is studied in axial symmetrical, warped, six-dimensional brane world, using a recently proposed topological Abelian string-vortex solution as background. It was found, that the massless gauge field fluctuations follow four-dimensional Maxwell equations in the Lorenz gauge. The massless zero mode is localized when the thickness of the string vortex is less than 5β/4πe 2 v 2 and there are no other localized massless modes. There is also an infinite of nonlocalized massive Fourier modes, that follow four-dimensional Proca equations with a continuous spectrum. To compute the corrections to the Coulomb potential, a radial cutoff was introduced, in order to achieve a discrete mass spectrum. As a main result, a (R o /βR 2 ) correction was found for the four-dimensional effective Coulomb law; the result is in correspondence with the observed behavior of the Coulomb potential at today's measurable distances.
Chiral symmetry breaking and nonperturbative scale anomaly in gauge field theories
International Nuclear Information System (INIS)
Miranskij, V.A.; Gusynin, V.P.
1987-01-01
The nonperturbative dynamics of chiral and scale symmetry breaking in asymtotically free and non-asymptotically free (with an ultraviolet stable fixed point) vector-like gauge theories is investigated. In the two-loop approximation analytical expressions for the chiral and gluon condensates are obtained. The hypothesis about a soft behaviour at small distances of composite operators in non-asymptotically free gauge theories with a fixed point is put forward and substantiated. It is shown that in these theories the form of the scale anomaly depends on the type of the phase in coupling constant to which it relates. A new dilaton effective lagrangian for glueball and chiral fields is suggested. The mass relation for the single scalar fermion-antifermion bound state is obtained. The important ingredient of this approach is a large (d≅ 2) dynamical dimension of composite chiral fields. The application of this approach to QCD and technicolour models is discussed
Double gauge invariance and covariantly-constant vector fields in Weyl geometry
Kassandrov, Vladimir V.; Rizcallah, Joseph A.
2014-08-01
The wave equation and equations of covariantly-constant vector fields (CCVF) in spaces with Weyl nonmetricity turn out to possess, in addition to the canonical conformal-gauge, a gauge invariance of another type. On a Minkowski metric background, the CCVF system alone allows us to pin down the Weyl 4-metricity vector, identified herein with the electromagnetic potential. The fundamental solution is given by the ordinary Lienard-Wiechert field, in particular, by the Coulomb distribution for a charge at rest. Unlike the latter, however, the magnitude of charge is necessarily unity, "elementary", and charges of opposite signs correspond to retarded and advanced potentials respectively, thus establishing a direct connection between the particle/antiparticle asymmetry and the "arrow of time".
Noncommutative o*(N) and usp*(2N) algebras and the corresponding gauge field theories
International Nuclear Information System (INIS)
Bars, I.; Sheikh-Jabbari, M.M.; Vasiliev, M.A.
2001-03-01
The extension of the noncommutative u * (N) Lie algebra to noncommutative orthogonal and symplectic Lie algebras is studied. Using an anti-automorphism of the star-matrix algebra, we show that the u * (N) can consistently be restricted to o * (N) and usp * (N) algebras that have new mathematical structures. We give explicit fundamental matrix representations of these algebras, through which the formulation for the corresponding noncommutative gauge field theories are obtained. In addition, we present a D-brane configuration with an orientifold which realizes geometrically our algebraic construction, thus embedding the new noncommutative gauge theories in superstring theory in the presence of a constant background magnetic field. Some algebraic generalizations that may have applications in other areas of physics are also discussed. (author)
On a stochastic process associated to non-abelian gauge fields
International Nuclear Information System (INIS)
Vilela Mendes, R.
1989-01-01
A stochastic process is constructed from a ground state measure that generalizes to non-abelian fields the ground state of abelian (free) gauge fields without fermions. Using a latticized version one shows how the process leads to a well-defined quantum theory in the Schroedinger representation. An analysis of the qualitative behaviour of the theory seems to imply a quasi-free behaviour at short distances and a maximally disordered field strength configuration for the low-momentum component of the ground state. Scaling relations for the mass gap are inferred from the theory of small random perturbations of dynamical systems. (orig.)
Strongly correlated states of a small cold-atom cloud from geometric gauge fields
International Nuclear Information System (INIS)
Julia-Diaz, B.; Dagnino, D.; Barberan, N.; Guenter, K. J.; Dalibard, J.; Grass, T.; Lewenstein, M.
2011-01-01
Using exact diagonalization for a small system of cold bosonic atoms, we analyze the emergence of strongly correlated states in the presence of an artificial magnetic field. This gauge field is generated by a laser beam that couples two internal atomic states, and it is related to Berry's geometrical phase that emerges when an atom follows adiabatically one of the two eigenstates of the atom-laser coupling. Our approach allows us to go beyond the adiabatic approximation, and to characterize the generalized Laughlin wave functions that appear in the strong magnetic-field limit.
Strongly correlated states of a small cold-atom cloud from geometric gauge fields
Energy Technology Data Exchange (ETDEWEB)
Julia-Diaz, B. [Dept. ECM, Facultat de Fisica, U. Barcelona, E-08028 Barcelona (Spain); ICFO-Institut de Ciencies Fotoniques, Parc Mediterrani de la Tecnologia, E-08860 Barcelona (Spain); Dagnino, D.; Barberan, N. [Dept. ECM, Facultat de Fisica, U. Barcelona, E-08028 Barcelona (Spain); Guenter, K. J.; Dalibard, J. [Laboratoire Kastler Brossel, CNRS, UPMC, Ecole Normale Superieure, 24 rue Lhomond, F-75005 Paris (France); Grass, T. [ICFO-Institut de Ciencies Fotoniques, Parc Mediterrani de la Tecnologia, E-08860 Barcelona (Spain); Lewenstein, M. [ICFO-Institut de Ciencies Fotoniques, Parc Mediterrani de la Tecnologia, E-08860 Barcelona (Spain); ICREA-Institucio Catalana de Recerca i Estudis Avancats, E-08010 Barcelona (Spain)
2011-11-15
Using exact diagonalization for a small system of cold bosonic atoms, we analyze the emergence of strongly correlated states in the presence of an artificial magnetic field. This gauge field is generated by a laser beam that couples two internal atomic states, and it is related to Berry's geometrical phase that emerges when an atom follows adiabatically one of the two eigenstates of the atom-laser coupling. Our approach allows us to go beyond the adiabatic approximation, and to characterize the generalized Laughlin wave functions that appear in the strong magnetic-field limit.
Constant external fields in gauge theory and the spin 0, 1/2, 1 path integrals
International Nuclear Information System (INIS)
Reuter, M.; Schmidt, M.G.
1996-10-01
We investigate the usefulness of the ''string-inspired technique'' for gauge theory calculations in a constant external field background. Our approach is based on Strassler's worldline path integral approach to the Bern-Kosower formalism, and on the construction of worldline (super-) Green's functions incorporating external fields as well as internal propagators. The worldline path integral representation of the gluon loop is reexamined in detail. We calculate the two-loop effective actions induced for a constant external field by a scalar and spinor loop, and the corresponding one-loop effective action in the gluon loop case. (orig.)
An introduction of gauge field by the Lie-isotopic lifting of the Hilbert space
International Nuclear Information System (INIS)
Nishioka, M.
1984-01-01
It is introduced the gauge field by the Lie-isotopic lifting of the Hilbert space. Our method is different from other's in that the commutator between the isotropic element and the generators of the Lie algebra does not vanish in our case, but vanishes in other cases. Our method uses the Lie-isotopic lifting of the Hilbert space, but others do not use it
Nilpotent BRST charge without auxillary B fields in quantum gauge theories
International Nuclear Information System (INIS)
Tsai, E.C.
1991-01-01
This paper introduces a modified BRST transformation for non-Abelian gauge theories. In this transformation, there is no need to introduce auxiliary B fields, yet the generatior Q for the modified transformation is nilpotent and commutes with the Hamiltonian. The Lagrangian is no longer invariant under Q, but the quantum theory which is defined by the Hamiltonian is still symmetric with respect to the transformation generated by Q
On the algebraic structure of self-dual gauge fields and sigma models
International Nuclear Information System (INIS)
Bais, F.A.; Sasaki, R.
1983-01-01
An extensive and detailed analysis of self-dual gauge fields, in particular with axial symmetry, is presented, culminating in a purely algebraic procedure to generate solutions. The method which is particularly suited for the construction of multimonopole solutions for a theory with arbitrary G, is also applicable to a wide class of non-linear sigma models. The relevant symmetries as well as the associated linear problems which underly the exact solubility of the problem, are constructed and discussed in detail. (orig.)
International Nuclear Information System (INIS)
Warner, R.C.; Joshi, G.C.
1979-01-01
A simple rule is presented for calculating the contributions to the interaction potentials between constituent particles for a family of multiquark states, due to the presence of a semi-classical gauge field configuration which exists in a single SU(2) subgroup of colour SU(3). In multiquark states beyond the baryon many-body potential terms are found. The static (Wilson loop) limit is sufficient to elucidate the dependence of the potential on the colour structure of the multiquark state
International Nuclear Information System (INIS)
Harada, Masayasu; Kikukawa, Yoshio; Yamawaki, Koichi
2003-01-01
This issue presents the important recent progress in both theoretical and phenomenological issues of strong coupling gauge theories, with/without supersymmetry and extra dimensions, etc. Emphasis in a placed on dynamical symmetry breaking with large anomalous dimensions governed by the dynamics near the nontrivial fixed point. Also presented are recent developments of the corresponding effective field theories. The 43 of the presented papers are indexed individually. (J.P.N)
Reduction of the Poincare gauge field equations by means of a duality rotation
International Nuclear Information System (INIS)
Mielke, E.W.
1981-10-01
A rather general procedure is developed in order to reduce the two field equations of the Poincare gauge theory of gravity by a modified ansatz for the curvature tensor involving double duality. In the case of quasi-linear Lagrangians of the Yang-Mills type it is shown that non-trivial torsion solutions with duality properties necessarily ''live'' on an Einstein space as metrical background. (author)
Spontaneous symmetry breaking, and strings defects in hypercomplex gauge field theories
Energy Technology Data Exchange (ETDEWEB)
Cartas-Fuentevilla, R. [Universidad Autonoma de Puebla, Instituto de Fisica, Puebla, Pue. (Mexico); Meza-Aldama, O. [Universidad Autonoma de Puebla, Facultad de Ciencias Fisico-Matematicas, Puebla, Pue. (Mexico)
2016-02-15
Inspired by the appearance of split-complex structures in the dimensional reduction of string theory, and in the theories emerging as byproducts, we study the hypercomplex formulation of Abelian gauge field theories by incorporating a new complex unit to the usual complex one. The hypercomplex version of the traditional Mexican hat potential associated with the U(1) gauge field theory, corresponds to a hybrid potential with two real components, and with U(1) x SO(1,1) as symmetry group. Each component corresponds to a deformation of the hat potential, with the appearance of a new degenerate vacuum. Hypercomplex electrodynamics will show novel properties, such as spontaneous symmetry breaking scenarios with running masses for the vectorial and scalar Higgs fields, and such as Aharonov-Bohm type strings defects as exact solutions; these topological defects may be detected only by quantum interference of charged particles through gauge invariant loop integrals. In a particular limit, the hyperbolic electrodynamics does not admit topological defects associated with continuous symmetries. (orig.)
International Nuclear Information System (INIS)
Kenyon, I.R.
1986-01-01
Modern theories of the interactions between fundamental particles are all gauge theories. In the case of gravitation, application of this principle to space-time leads to Einstein's theory of general relativity. All the other interactions involve the application of the gauge principle to internal spaces. Electromagnetism serves to introduce the idea of a gauge field, in this case the electromagnetic field. The next example, the strong force, shows unique features at long and short range which have their origin in the self-coupling of the gauge fields. Finally the unification of the description of the superficially dissimilar electromagnetic and weak nuclear forces completes the picture of successes of the gauge principle. (author)
Quantum field theory III. Gauge theory. A bridge between mathematicians and physicists
International Nuclear Information System (INIS)
Zeidler, Eberhard
2011-01-01
In this third volume of his modern introduction to quantum field theory, Eberhard Zeidler examines the mathematical and physical aspects of gauge theory as a principle tool for describing the four fundamental forces which act in the universe: gravitative, electromagnetic, weak interaction and strong interaction. Volume III concentrates on the classical aspects of gauge theory, describing the four fundamental forces by the curvature of appropriate fiber bundles. This must be supplemented by the crucial, but elusive quantization procedure. The book is arranged in four sections, devoted to realizing the universal principle force equals curvature: Part I: The Euclidean Manifold as a Paradigm Part II: Ariadne's Thread in Gauge Theory Part III: Einstein's Theory of Special Relativity Part IV: Ariadne's Thread in Cohomology For students of mathematics the book is designed to demonstrate that detailed knowledge of the physical background helps to reveal interesting interrelationships among diverse mathematical topics. Physics students will be exposed to a fairly advanced mathematics, beyond the level covered in the typical physics curriculum. Quantum Field Theory builds a bridge between mathematicians and physicists, based on challenging questions about the fundamental forces in the universe (macrocosmos), and in the world of elementary particles (microcosmos). (orig.)
Quantum field theory III. Gauge theory. A bridge between mathematicians and physicists
Energy Technology Data Exchange (ETDEWEB)
Zeidler, Eberhard [Max Planck Institute for Mathematics in the Sciences, Leipzig (Germany)
2011-07-01
In this third volume of his modern introduction to quantum field theory, Eberhard Zeidler examines the mathematical and physical aspects of gauge theory as a principle tool for describing the four fundamental forces which act in the universe: gravitative, electromagnetic, weak interaction and strong interaction. Volume III concentrates on the classical aspects of gauge theory, describing the four fundamental forces by the curvature of appropriate fiber bundles. This must be supplemented by the crucial, but elusive quantization procedure. The book is arranged in four sections, devoted to realizing the universal principle force equals curvature: Part I: The Euclidean Manifold as a Paradigm Part II: Ariadne's Thread in Gauge Theory Part III: Einstein's Theory of Special Relativity Part IV: Ariadne's Thread in Cohomology For students of mathematics the book is designed to demonstrate that detailed knowledge of the physical background helps to reveal interesting interrelationships among diverse mathematical topics. Physics students will be exposed to a fairly advanced mathematics, beyond the level covered in the typical physics curriculum. Quantum Field Theory builds a bridge between mathematicians and physicists, based on challenging questions about the fundamental forces in the universe (macrocosmos), and in the world of elementary particles (microcosmos). (orig.)
Discrete finite nilpotent Lie analogs: New models for unified gauge field theory
International Nuclear Information System (INIS)
Kornacker, K.
1978-01-01
To each finite dimensional real Lie algebra with integer structure constants there corresponds a countable family of discrete finite nilpotent Lie analogs. Each finite Lie analog maps exponentially onto a finite unipotent group G, and is isomorphic to the Lie algebra of G. Reformulation of quantum field theory in discrete finite form, utilizing nilpotent Lie analogs, should elminate all divergence problems even though some non-Abelian gauge symmetry may not be spontaneously broken. Preliminary results in the new finite representation theory indicate that a natural hierarchy of spontaneously broken symmetries can arise from a single unbroken non-Abelian gauge symmetry, and suggest the possibility of a new unified group theoretic interpretation for hadron colors and flavors
Effective field theory analysis on μ problem in low-scale gauge mediation
International Nuclear Information System (INIS)
Zheng Sibo
2012-01-01
Supersymmetric models based on the scenario of gauge mediation often suffer from the well-known μ problem. In this paper, we reconsider this problem in low-scale gauge mediation in terms of effective field theory analysis. In this paradigm, all high energy input soft mass can be expressed via loop expansions. If the corrections coming from messenger thresholds are small, as we assume in this letter, then all RG evaluations can be taken as linearly approximation for low-scale supersymmetric breaking. Due to these observations, the parameter space can be systematically classified and studied after constraints coming from electro-weak symmetry breaking are imposed. We find that some old proposals in the literature are reproduced, and two new classes are uncovered. We refer to a microscopic model, where the specific relations among coefficients in one of the new classes are well motivated. Also, we discuss some primary phenomenologies.
Supersymmetric gauge theories, quantization of M{sub flat}, and conformal field theory
Energy Technology Data Exchange (ETDEWEB)
Teschner, J.; Vartanov, G.S.
2013-02-15
We propose a derivation of the correspondence between certain gauge theories with N=2 supersymmetry and conformal field theory discovered by Alday, Gaiotto and Tachikawa in the spirit of Seiberg-Witten theory. Based on certain results from the literature we argue that the quantum theory of the moduli spaces of flat SL(2,R)-connections represents a nonperturbative ''skeleton'' of the gauge theory, protected by supersymmetry. It follows that instanton partition functions can be characterized as solutions to a Riemann-Hilbert type problem. In order to solve it, we describe the quantization of the moduli spaces of flat connections explicitly in terms of two natural sets of Darboux coordinates. The kernel describing the relation between the two pictures represents the solution to the Riemann Hilbert problem, and is naturally identified with the Liouville conformal blocks.
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
An Ar threesome: Matrix models, 2d conformal field theories, and 4dN=2 gauge theories
International Nuclear Information System (INIS)
Schiappa, Ricardo; Wyllard, Niclas
2010-01-01
We explore the connections between three classes of theories: A r quiver matrix models, d=2 conformal A r Toda field theories, and d=4N=2 supersymmetric conformal A r quiver gauge theories. In particular, we analyze the quiver matrix models recently introduced by Dijkgraaf and Vafa (unpublished) and make detailed comparisons with the corresponding quantities in the Toda field theories and the N=2 quiver gauge theories. We also make a speculative proposal for how the matrix models should be modified in order for them to reproduce the instanton partition functions in quiver gauge theories in five dimensions.
Spinor matter fields in SL(2,C) gauge theories of gravity: Lagrangian and Hamiltonian approaches
Antonowicz, Marek; Szczyrba, Wiktor
1985-06-01
We consider the SL(2,C)-covariant Lagrangian formulation of gravitational theories with the presence of spinor matter fields. The invariance properties of such theories give rise to the conservation laws (the contracted Bianchi identities) having in the presence of matter fields a more complicated form than those known in the literature previously. A general SL(2,C) gauge theory of gravity is cast into an SL(2,C)-covariant Hamiltonian formulation. Breaking the SL(2,C) symmetry of the system to the SU(2) symmetry, by introducing a spacelike slicing of spacetime, we get an SU(2)-covariant Hamiltonian picture. The qualitative analysis of SL(2,C) gauge theories of gravity in the SU(2)-covariant formulation enables us to define the dynamical symplectic variables and the gauge variables of the theory under consideration as well as to divide the set of field equations into the dynamical equations and the constraints. In the SU(2)-covariant Hamiltonian formulation the primary constraints, which are generic for first-order matter Lagrangians (Dirac, Weyl, Fierz-Pauli), can be reduced. The effective matter symplectic variables are given by SU(2)-spinor-valued half-forms on three-dimensional slices of spacetime. The coupled Einstein-Cartan-Dirac (Weyl, Fierz-Pauli) system is analyzed from the (3+1) point of view. This analysis is complete; the field equations of the Einstein-Cartan-Dirac theory split into 18 gravitational dynamical equations, 8 dynamical Dirac equations, and 7 first-class constraints. The system has 4+8=12 independent degrees of freedom in the phase space.
Spinor matter fields in SL(2,C) gauge theories of gravity: Lagrangian and Hamiltonian approaches
International Nuclear Information System (INIS)
Antonowicz, M.; Szczyrba, W.
1985-01-01
We consider the SL(2,C)-covariant Lagrangian formulation of gravitational theories with the presence of spinor matter fields. The invariance properties of such theories give rise to the conservation laws (the contracted Bianchi identities) having in the presence of matter fields a more complicated form than those known in the literature previously. A general SL(2,C) gauge theory of gravity is cast into an SL(2,C)-covariant Hamiltonian formulation. Breaking the SL(2,C) symmetry of the system to the SU(2) symmetry, by introducing a spacelike slicing of spacetime, we get an SU(2)-covariant Hamiltonian picture. The qualitative analysis of SL(2,C) gauge theories of gravity in the SU(2)-covariant formulation enables us to define the dynamical symplectic variables and the gauge variables of the theory under consideration as well as to divide the set of field equations into the dynamical equations and the constraints. In the SU(2)-covariant Hamiltonian formulation the primary constraints, which are generic for first-order matter Lagrangians (Dirac, Weyl, Fierz-Pauli), can be reduced. The effective matter symplectic variables are given by SU(2)-spinor-valued half-forms on three-dimensional slices of spacetime. The coupled Einstein-Cartan-Dirac (Weyl, Fierz-Pauli) system is analyzed from the (3+1) point of view. This analysis is complete; the field equations of the Einstein-Cartan-Dirac theory split into 18 gravitational dynamical equations, 8 dynamical Dirac equations, and 7 first-class constraints. The system has 4+8 = 12 independent degrees of freedom in the phase space
International Nuclear Information System (INIS)
Bertschinger, E.
1987-01-01
Path integrals may be used to describe the statistical properties of a random field such as the primordial density perturbation field. In this framework the probability distribution is given for a Gaussian random field subjected to constraints such as the presence of a protovoid or supercluster at a specific location in the initial conditions. An algorithm has been constructed for generating samples of a constrained Gaussian random field on a lattice using Monte Carlo techniques. The method makes possible a systematic study of the density field around peaks or other constrained regions in the biased galaxy formation scenario, and it is effective for generating initial conditions for N-body simulations with rare objects in the computational volume. 21 references
Black holes with su(N) gauge field hair and superconducting horizons
Energy Technology Data Exchange (ETDEWEB)
Shepherd, Ben L.; Winstanley, Elizabeth [Consortium for Fundamental Physics, School of Mathematics and Statistics,The University of Sheffield,Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom)
2017-01-16
We present new planar dyonic black hole solutions of the su(N) Einstein-Yang-Mills equations in asymptotically anti-de Sitter space-time, focussing on su(2) and su(3) gauge groups. The magnetic part of the gauge field forms a condensate close to the planar event horizon. We compare the free energy of a non-Abelian hairy black hole with that of an embedded Reissner-Nordström-anti-de Sitter (RN-AdS) black hole having the same Hawking temperature and electric charge. We find that the hairy black holes have lower free energy. We present evidence that there is a phase transition at a critical temperature, above which the only solutions are embedded RN-AdS black holes. At the critical temperature, an RN-AdS black hole can decay into a hairy black hole, and it is thermodynamically favourable to do so. Working in the probe limit, we compute the frequency-dependent conductivity, and find that enlarging the gauge group from su(2) to su(3) eliminates a divergence in the conductivity at nonzero frequency.
Black holes with su(N) gauge field hair and superconducting horizons
International Nuclear Information System (INIS)
Shepherd, Ben L.; Winstanley, Elizabeth
2017-01-01
We present new planar dyonic black hole solutions of the su(N) Einstein-Yang-Mills equations in asymptotically anti-de Sitter space-time, focussing on su(2) and su(3) gauge groups. The magnetic part of the gauge field forms a condensate close to the planar event horizon. We compare the free energy of a non-Abelian hairy black hole with that of an embedded Reissner-Nordström-anti-de Sitter (RN-AdS) black hole having the same Hawking temperature and electric charge. We find that the hairy black holes have lower free energy. We present evidence that there is a phase transition at a critical temperature, above which the only solutions are embedded RN-AdS black holes. At the critical temperature, an RN-AdS black hole can decay into a hairy black hole, and it is thermodynamically favourable to do so. Working in the probe limit, we compute the frequency-dependent conductivity, and find that enlarging the gauge group from su(2) to su(3) eliminates a divergence in the conductivity at nonzero frequency.
From the Dyson-Schwinger to the Transport Equation in the Background Field Gauge of QCD
Wang, Q; Stöcker, H; Greiner, W
2003-01-01
The non-equilibrium quantum field dynamics is usually described in the closed-time-path formalism. The initial state correlations are introduced into the generating functional by non-local source terms. We propose a functional approach to the Dyson-Schwinger equation, which treats the non-local and local source terms in the same way. In this approach, the generating functional is formulated for the connected Green functions and one-particle-irreducible vertices. The great advantages of our approach over the widely used two-particle-irreducible method are that it is much simpler and that it is easy to implement the procedure in a computer program to automatically generate the Feynman diagrams for a given process. The method is then applied to a pure gluon plasma to derive the gauge-covariant transport equation from the Dyson-Schwinger equation in the background covariant gauge. We discuss the structure of the kinetic equation and show its relationship with the classical one. We derive the gauge-covariant colli...
From 6D superconformal field theories to dynamic gauged linear sigma models
Apruzzi, Fabio; Hassler, Falk; Heckman, Jonathan J.; Melnikov, Ilarion V.
2017-09-01
Compactifications of six-dimensional (6D) superconformal field theories (SCFTs) on four- manifolds generate a large class of novel two-dimensional (2D) quantum field theories. We consider in detail the case of the rank-one simple non-Higgsable cluster 6D SCFTs. On the tensor branch of these theories, the gauge group is simple and there are no matter fields. For compactifications on suitably chosen Kähler surfaces, we present evidence that this provides a method to realize 2D SCFTs with N =(0 ,2 ) supersymmetry. In particular, we find that reduction on the tensor branch of the 6D SCFT yields a description of the same 2D fixed point that is described in the UV by a gauged linear sigma model (GLSM) in which the parameters are promoted to dynamical fields, that is, a "dynamic GLSM" (DGLSM). Consistency of the model requires the DGLSM to be coupled to additional non-Lagrangian sectors obtained from reduction of the antichiral two-form of the 6D theory. These extra sectors include both chiral and antichiral currents, as well as spacetime filling noncritical strings of the 6D theory. For each candidate 2D SCFT, we also extract the left- and right-moving central charges in terms of data of the 6D SCFT and the compactification manifold.
Equations of motion of higher-spin gauge fields as a free differential algebra
International Nuclear Information System (INIS)
Vasil'ev, M.A.
1988-01-01
It is shown that the introduction of auxiliary dynamical variables that generalize the gravitational Weyl tensor permits one to reduce the equations of motion of free massless fields of all spins in the anti-de Sitter O(3,2) space to a form characteristic of free differential algebras. The equations of motion of auxiliary gauge fields introduced previously are modified analogously. Arguments are presented to the effect that the equations of motion of interacting massless fields of all spins should be described in terms of a free differential algebra which is a deformation of a known free differential algebra generated by 1- and 0-forms in the adjoint representation of a nonabelian superalgebra of higher spins and auxiliary fields
International Nuclear Information System (INIS)
Membiela, Federico Agustín; Bellini, Mauricio
2010-01-01
Using a semiclassical approach to Gravitoelectromagnetic Inflation (GEMI), we study the origin and evolution of seminal inflaton and electromagnetic fields in the early inflationary universe from a 5D vacuum state. We use simultaneously the Lorentz and Feynman gauges. Our formalism is naturally not conformal invariant on the effective 4D de Sitter metric, which make possible the super adiabatic amplification of electric and magnetic field modes during the early inflationary epoch of the universe on cosmological scales. This is the first time that solutions for the electric field fluctuations are investigated in a systematic way as embeddings for inflationary models in 4D. An important and new result here obtained is that the spectrum of the electric field fluctuations depend with the scale, such that the spectral index increases quadratically as the scale decreases
Energy Technology Data Exchange (ETDEWEB)
Membiela, Federico Agustín; Bellini, Mauricio, E-mail: mbellini@mdp.edu.ar, E-mail: membiela@mdp.edu.ar [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350, (7600) Mar del Plata (Argentina)
2010-10-01
Using a semiclassical approach to Gravitoelectromagnetic Inflation (GEMI), we study the origin and evolution of seminal inflaton and electromagnetic fields in the early inflationary universe from a 5D vacuum state. We use simultaneously the Lorentz and Feynman gauges. Our formalism is naturally not conformal invariant on the effective 4D de Sitter metric, which make possible the super adiabatic amplification of electric and magnetic field modes during the early inflationary epoch of the universe on cosmological scales. This is the first time that solutions for the electric field fluctuations are investigated in a systematic way as embeddings for inflationary models in 4D. An important and new result here obtained is that the spectrum of the electric field fluctuations depend with the scale, such that the spectral index increases quadratically as the scale decreases.
An Upper Bound on the Entropy of Constrained 2d Fields
DEFF Research Database (Denmark)
Forchhammer, Søren; Justesen, Jørn
1998-01-01
An upper bound on the entropy of constrained 2D fields is presented. The constraints have to be symmetric in (at least) one of the two directions. The bound generalizes (in a weaker form) the bound of Calkin and Wilf (see SIAM Journal of Discrete Mathematics, vol.11, p.54-60, 1998) which is valid...
Directory of Open Access Journals (Sweden)
K.J.B. Ghosh
2018-01-01
Full Text Available We consider four-dimensional chiral gauge theories defined over a spacetime manifold with topology R3×S1 and periodic boundary conditions over the compact dimension. The effective gauge-field action is calculated for Abelian U(1 gauge fields Aμ(x which depend on all four spacetime coordinates (including the coordinate x4∈S1 of the compact dimension and have vanishing components A4(x (implying trivial holonomies in the 4-direction. Our calculation shows that the effective gauge-field action contains a local Chern–Simons-like term which violates Lorentz and CPT invariance. This result is established perturbatively with a generalized Pauli–Villars regularization and nonperturbatively with a lattice regularization based on Ginsparg–Wilson fermions.
Ghosh, K. J. B.; Klinkhamer, F. R.
2018-01-01
We consider four-dimensional chiral gauge theories defined over a spacetime manifold with topology R3 ×S1 and periodic boundary conditions over the compact dimension. The effective gauge-field action is calculated for Abelian U (1) gauge fields Aμ (x) which depend on all four spacetime coordinates (including the coordinate x4 ∈S1 of the compact dimension) and have vanishing components A4 (x) (implying trivial holonomies in the 4-direction). Our calculation shows that the effective gauge-field action contains a local Chern-Simons-like term which violates Lorentz and CPT invariance. This result is established perturbatively with a generalized Pauli-Villars regularization and nonperturbatively with a lattice regularization based on Ginsparg-Wilson fermions.
Relating double field theory to the scalar potential of N=2 gauged supergravity
Energy Technology Data Exchange (ETDEWEB)
Blumenhagen, Ralph [Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), Föhringer Ring 6, München, 80805 (Germany); Font, Anamaria [Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), Föhringer Ring 6, München, 80805 (Germany); Arnold Sommerfeld Center for Theoretical Physics, LMU,Theresienstr. 37, München, 80333 (Germany); Plauschinn, Erik [Arnold Sommerfeld Center for Theoretical Physics, LMU,Theresienstr. 37, München, 80333 (Germany)
2015-12-18
The double field theory action in the flux formulation is dimensionally reduced on a Calabi-Yau three-fold equipped with non-vanishing type IIB geometric and non-geometric fluxes. First, we rewrite the metric-dependent reduced DFT action in terms of quantities that can be evaluated without explicitly knowing the metric on the Calabi-Yau manifold. Second, using properties of special geometry we obtain the scalar potential of N=2 gauged supergravity. After an orientifold projection, this potential is consistent with the scalar potential arising from the flux-induced superpotential, plus an additional D-term contribution.
Colored, spinning classical particle in an external non-Abelian gauge field
International Nuclear Information System (INIS)
Arodz, H.
1982-04-01
Classical non-relativistic equations of motion are derived for a colored, spinning point-like particle in an external SU(2) gauge field from Dirac equation. It is found that in addition to the classical spin and color spin vectors, S, I, it is necessary to introduce a new classical dynamical variable [Jsup(ab)], a,b = 1,2,3, describing a mixing of the spin and color. The constraint relations between [Jsup(ab)], S, I are also found. (Auth.)
Vector-like fields, messenger mixing and the Higgs mass in gauge mediation
Energy Technology Data Exchange (ETDEWEB)
Fischler, Willy; Tangarife, Walter [Department of Physics and Texas Cosmology Center,The University of Texas at Austin,TX 78712 (United States)
2014-05-30
In order to generate, in the context of gauge mediation, a Higgs mass around 126 GeV that avoids the little hierarchy problem, we explore a set of models where the messengers are directly coupled to new vector-like fields at the TeV scale in addition to the usual low energy degrees of freedom. We find that in this context, stop masses lighter than 2 TeV and large A-terms are generated, thereby improving issues of fine tuning.
Far-field tsunami magnitude determined from ocean-bottom pressure gauge data around Japan
Baba, T.; Hirata, K.; Kaneda, Y.
2003-12-01
\\hspace*{3mm}Tsunami magnitude is the most fundamental parameter to scale tsunamigenic earthquakes. According to Abe (1979), the tsunami magnitude, Mt, is empirically related to the crest to trough amplitude, H, of the far-field tsunami wave in meters (Mt = logH + 9.1). Here we investigate the far-field tsunami magnitude using ocean-bottom pressure gauge data. The recent ocean-bottom pressure measurements provide more precise tsunami data with a high signal-to-noise ratio. \\hspace*{3mm}Japan Marine Science and Technology Center is monitoring ocean bottom pressure fluctuations using two submarine cables of depths of 1500 - 2400 m. These geophysical observatory systems are located off Cape Muroto, Southwest Japan, and off Hokkaido, Northern Japan. The ocean-bottom pressure data recorded with the Muroto and Hokkaido systems have been collected continuously since March, 1997 and October, 1999, respectively. \\hspace*{3mm}Over the period from March 1997 to June 2003, we have observed four far-field tsunami signals, generated by earthquakes, on ocean-bottom pressure records. These far-field tsunamis were generated by the 1998 Papua New Guinea eq. (Mw 7.0), 1999 Vanuatu eq. (Mw 7.2), 2001 Peru eq. (Mw 8.4) and 2002 Papua New Guinea eq. (Mw 7.6). Maximum amplitude of about 30 mm was recorded by the tsunami from the 2001 Peru earthquake. \\hspace*{3mm}Direct application of the Abe's empirical relation to ocean-bottom pressure gauge data underestimates tsunami magnitudes by about an order of magnitude. This is because the Abe's empirical relation was derived only from tsunami amplitudes with coastal tide gauges where tsunami is amplified by the shoaling of topography and the reflection at the coastline. However, these effects do not work for offshore tsunami in deep oceans. In general, amplification due to shoaling near the coastline is governed by the Green's Law, in which the tsunami amplitude is proportional to h-1/4, where h is the water depth. Wave amplitude also is
Energy Technology Data Exchange (ETDEWEB)
Steinmann, O [Bielefeld Univ. (F.R. Germany). Fakultaet fuer Physik
1975-01-01
Massive quantum electrodynamics of the electron is formulated as an LSZ theory of the electromagnetic field F(..mu nu..) and the electron-positron fields PSI. The interaction is introduced with the help of mathematically well defined subsidiary conditions. These are: 1) gauge invariance of the first kind, assumed to be generated by a conserved current j(..mu..); 2) the homogeneous Maxwell equations and a massive version of the inhomogeneous Maxwell equations; 3) a minimality condition concerning the high momentum behaviour of the theory. The inhomogeneous Maxwell equation is a linear differential equation connecting Fsub(..mu nu..) with the current Jsub(..mu..). No Lagrangian, no non-linear field equations, and no explicit expression of Jsub(..mu..) in terms of PSI, anti-PSI are needed. It is shown in perturbation theory that the proposed conditions fix the physically relevant (i.e. observable) quantities of the theory uniquely.
Unbounded representations of symmetry groups in gauge quantum field theory. Pt. 1
International Nuclear Information System (INIS)
Voelkel, A.H.
1983-01-01
Symmetry groups and especially the covariance (substitution rules) of the basic fields in a gauge quantum field theory of the Wightman-Garding type are investigated. By means of the continuity properties hidden in the substitution rules it is shown that every unbounded form-isometric representation U of a Lie group has a form-skew-symmetric differential deltaU with dense domain in the unphysical Hilbert space. Necessary and sufficient conditions for the existence of the closures of U and deltaU as well as for the isometry of U are derived. It is proved that a class of representations of the transition group enforces a relativistic confinement mechanism, by which some or all basic fields are confined but certain mixed products of them are not. (orig.)
Notes on the measurement of stress by resistance gauges in the presence of a magnetic field
International Nuclear Information System (INIS)
Armand, G.; Lapujoulade, J.
1961-01-01
The technique of stress measurement by resistance gauges is well known. Although it is not yet perfect it possesses many advantages and shows great possibilities. In the presence of a magnetic field the measurement is perturbed by certain phenomena, and we have undertaken to calculate their order of magnitude with a view to establishing the error involved in the measurement. Our problem was to measure the stresses on the various parts of the magnet in the synchrotron Saturne. It is known that the induction passes from a value of about nil to 15000 gauss in 0.8 second, and returns to zero in the same time interval; this cycle recurs every 3.2 seconds. In order to isolate the effects the problem of measurements in a static field will be examined first, after which the results obtained will be extended to the case of dynamic fields. (author) [fr
Feynman rules for the Standard Model Effective Field Theory in R ξ -gauges
Dedes, A.; Materkowska, W.; Paraskevas, M.; Rosiek, J.; Suxho, K.
2017-06-01
We assume that New Physics effects are parametrized within the Standard Model Effective Field Theory (SMEFT) written in a complete basis of gauge invariant operators up to dimension 6, commonly referred to as "Warsaw basis". We discuss all steps necessary to obtain a consistent transition to the spontaneously broken theory and several other important aspects, including the BRST-invariance of the SMEFT action for linear R ξ -gauges. The final theory is expressed in a basis characterized by SM-like propagators for all physical and unphysical fields. The effect of the non-renormalizable operators appears explicitly in triple or higher multiplicity vertices. In this mass basis we derive the complete set of Feynman rules, without resorting to any simplifying assumptions such as baryon-, lepton-number or CP conservation. As it turns out, for most SMEFT vertices the expressions are reasonably short, with a noticeable exception of those involving 4, 5 and 6 gluons. We have also supplemented our set of Feynman rules, given in an appendix here, with a publicly available Mathematica code working with the FeynRules package and producing output which can be integrated with other symbolic algebra or numerical codes for automatic SMEFT amplitude calculations.
Matter fields near quantum critical point in (2+1)-dimensional U(1) gauge theory
International Nuclear Information System (INIS)
Liu Guozhu; Li Wei; Cheng Geng
2010-01-01
We study chiral phase transition and confinement of matter fields in (2+1)-dimensional U(1) gauge theory of massless Dirac fermions and scalar bosons. The vanishing scalar boson mass, r=0, defines a quantum critical point between the Higgs phase and the Coulomb phase. We consider only the critical point r=0 and the Coulomb phase with r>0. The Dirac fermion acquires a dynamical mass when its flavor is less than certain critical value N f c , which depends quantitatively on the flavor N b and the scalar boson mass r. When N f f c , the matter fields carrying internal gauge charge are all confined if r≠0 but are deconfined at the quantum critical point r=0. The system has distinct low-energy elementary excitations at the critical point r=0 and in the Coulomb phase with r≠0. We calculate the specific heat and susceptibility of the system at r=0 and r≠0, which can help to detect the quantum critical point and to judge whether dynamical fermion mass generation takes place.
Water Bridging Dynamics of Polymerase Chain Reaction in the Gauge Theory Paradigm of Quantum Fields
Directory of Open Access Journals (Sweden)
L. Montagnier
2017-05-01
Full Text Available We discuss the role of water bridging the DNA-enzyme interaction by resorting to recent results showing that London dispersion forces between delocalized electrons of base pairs of DNA are responsible for the formation of dipole modes that can be recognized by Taq polymerase. We describe the dynamic origin of the high efficiency and precise targeting of Taq activity in PCR. The spatiotemporal distribution of interaction couplings, frequencies, amplitudes, and phase modulations comprise a pattern of fields which constitutes the electromagnetic image of DNA in the surrounding water, which is what the polymerase enzyme actually recognizes in the DNA water environment. The experimental realization of PCR amplification, achieved through replacement of the DNA template by the treatment of pure water with electromagnetic signals recorded from viral and bacterial DNA solutions, is found consistent with the gauge theory paradigm of quantum fields.
Dual gauge field theory of quantum liquid crystals in three dimensions
International Nuclear Information System (INIS)
Beekman, Aron J.; Nissinen, Jaakko; Wu, Kai; Zaanen, Jan
2017-01-01
The dislocation-mediated quantum melting of solids into quantum liquid crystals is extended from two to three spatial dimensions, using a generalization of boson-vortex or Abelian-Higgs duality. Dislocations are now Burgers-vector-valued strings that trace out worldsheets in space-time while the phonons of the solid dualize into two-form (Kalb-Ramond) gauge fields. We propose an effective dual Higgs potential that allows for restoring translational symmetry in either one, two, or three directions, leading to the quantum analogues of columnar, smectic, or nematic liquid crystals. In these phases, transverse phonons turn into gapped, propagating modes, while compressional stress remains massless. Rotational Goldstone modes emerge whenever translational symmetry is restored. Lastly, we also consider the effective electromagnetic response of electrically charged quantum liquid crystals, and find among other things that as a hard principle only two out of the possible three rotational Goldstone modes are observable using propagating electromagnetic fields.
Dual gauge field theory of quantum liquid crystals in three dimensions
Beekman, Aron J.; Nissinen, Jaakko; Wu, Kai; Zaanen, Jan
2017-10-01
The dislocation-mediated quantum melting of solids into quantum liquid crystals is extended from two to three spatial dimensions, using a generalization of boson-vortex or Abelian-Higgs duality. Dislocations are now Burgers-vector-valued strings that trace out worldsheets in space-time while the phonons of the solid dualize into two-form (Kalb-Ramond) gauge fields. We propose an effective dual Higgs potential that allows for restoring translational symmetry in either one, two, or three directions, leading to the quantum analogues of columnar, smectic, or nematic liquid crystals. In these phases, transverse phonons turn into gapped, propagating modes, while compressional stress remains massless. Rotational Goldstone modes emerge whenever translational symmetry is restored. We also consider the effective electromagnetic response of electrically charged quantum liquid crystals, and find among other things that as a hard principle only two out of the possible three rotational Goldstone modes are observable using propagating electromagnetic fields.
Unbounded representations of symmetry groups in gauge quantum field theory. II. Integration
International Nuclear Information System (INIS)
Voelkel, A.H.
1986-01-01
Within the gauge quantum field theory of the Wightman--Garding type, the integration of representations of Lie algebras is investigated. By means of the covariance condition (substitution rules) for the basic fields, it is shown that a form skew-symmetric representation of a Lie algebra can be integrated to a form isometric and in general unbounded representation of the universal covering group of a corresponding Lie group provided the conditions (Nelson, Sternheimer, etc.), which are well known for the case of Hilbert or Banach representations, hold. If a form isometric representation leaves the subspace from which the physical Hilbert space is obtained via factorization and completion invariant, then the same is proved to be true for its differential. Conversely, a necessary and sufficient condition is derived for the transmission of the invariance of this subspace under a form skew-symmetric representation of a Lie algebra to its integral
Classical field theory on electrodynamics, non-Abelian gauge theories and gravitation
Scheck, Florian
2012-01-01
The book describes Maxwell's equations first in their integral, directly testable form, then moves on to their local formulation. The first two chapters cover all essential properties of Maxwell's equations, including their symmetries and their covariance in a modern notation. Chapter 3 is devoted to Maxwell theory as a classical field theory and to solutions of the wave equation. Chapter 4 deals with important applications of Maxwell theory. It includes topical subjects such as metamaterials with negative refraction index and solutions of Helmholtz' equation in paraxial approximation relevant for the description of laser beams. Chapter 5 describes non-Abelian gauge theories from a classical, geometric point of view, in analogy to Maxwell theory as a prototype, and culminates in an application to the U(2) theory relevant for electroweak interactions. The last chapter 6 gives a concise summary of semi-Riemannian geometry as the framework for the classical field theory of gravitation. The chapter concludes wit...
Strings, gauge fields, and the geometry behind the legacy of Maximilian Kreuzer
Katzarkov, Ludmil; Knapp, Johanna; Rashkov, Radoslav; Scheidegger, Emanuel
2012-01-01
This book contains exclusively invited contributions from collaborators of Maximilian Kreuzer, giving accounts of his scientific legacy and original articles from renowned theoretical physicists and mathematicians, including Victor Batyrev, Philip Candelas, Michael Douglas, Alexei Morozov, Joseph Polchinski, Peter van Nieuwenhuizen, and Peter West. Besides a collection of review and research articles from high-profile researchers in string theory and related fields of mathematics (in particular, algebraic geometry) which discuss recent progress in the exploration of string theory vacua and corresponding mathematical developments, this book contains a pedagogical account of the important work of Brandt, Dragon, and Kreuzer on classification of anomalies in gauge theories. This highly cited work, which is also quoted in the textbook of Steven Weinberg on quantum field theory, has not yet been presented in full detail except in private lecture notes by Norbert Dragon. Similarly, the software package PALP (Packag...
Testing coordinate measuring arms with a geometric feature-based gauge: in situ field trials
Cuesta, E.; Alvarez, B. J.; Patiño, H.; Telenti, A.; Barreiro, J.
2016-05-01
This work describes in detail the definition of a procedure for calibrating and evaluating coordinate measuring arms (AACMMs or CMAs). CMAs are portable coordinate measuring machines that have been widely accepted in industry despite their sensitivity to the skill and experience of the operator in charge of the inspection task. The procedure proposed here is based on the use of a dimensional gauge that incorporates multiple geometric features, specifically designed for evaluating the measuring technique when CMAs are used, at company facilities (workshops or laboratories) and by the usual operators who handle these devices in their daily work. After establishing the procedure and manufacturing the feature-based gauge, the research project was complemented with diverse in situ field tests performed with the collaboration of companies that use these devices in their inspection tasks. Some of the results are presented here, not only comparing different operators but also comparing different companies. The knowledge extracted from these experiments has allowed the procedure to be validated, the defects of the methodologies currently used for in situ inspections to be detected, and substantial improvements for increasing the reliability of these portable instruments to be proposed.
Testing coordinate measuring arms with a geometric feature-based gauge: in situ field trials
International Nuclear Information System (INIS)
Cuesta, E; Alvarez, B J; Patiño, H; Telenti, A; Barreiro, J
2016-01-01
This work describes in detail the definition of a procedure for calibrating and evaluating coordinate measuring arms (AACMMs or CMAs). CMAs are portable coordinate measuring machines that have been widely accepted in industry despite their sensitivity to the skill and experience of the operator in charge of the inspection task. The procedure proposed here is based on the use of a dimensional gauge that incorporates multiple geometric features, specifically designed for evaluating the measuring technique when CMAs are used, at company facilities (workshops or laboratories) and by the usual operators who handle these devices in their daily work. After establishing the procedure and manufacturing the feature-based gauge, the research project was complemented with diverse in situ field tests performed with the collaboration of companies that use these devices in their inspection tasks. Some of the results are presented here, not only comparing different operators but also comparing different companies. The knowledge extracted from these experiments has allowed the procedure to be validated, the defects of the methodologies currently used for in situ inspections to be detected, and substantial improvements for increasing the reliability of these portable instruments to be proposed. (paper)
International Nuclear Information System (INIS)
Cabral-Rosetti, L.G.; Bernabeu, J.; Vidal, J.
2000-01-01
We present a computation of the charge and the magnetic moment of the neutrino in the recently developed electro-weak background field method and in the linear R ξ L gauge. First, we deduce a formal Ward-Takahashi identity which implies the immediate cancellation of the neutrino electric charge. This Ward-Takahashi identity is as simple as that for QED. The computation of the (proper and improper) one loop vertex diagrams contributing to the neutrino electric charge is also presented in an arbitrary gauge, checking in this way the Ward-Takahashi identity previously obtained. Finally, the calculation of the magnetic moment of the neutrino, in the minimal extension of the standard model with massive Dirac neutrinos, is presented, showing its gauge parameter and gauge structure independence explicitly. (orig.)
An ionization pressure gauge with LaB6 emitter for long-term operation in strong magnetic fields
Wenzel, U.; Pedersen, T. S.; Marquardt, M.; Singer, M.
2018-03-01
We report here on a potentially significant improvement in the design of neutral pressure gauges of the so-called ASDEX-type which were first used in the Axially Symmetric Divertor EXperiment (ASDEX). Such gauges are considered state-of-the-art and are in wide use in fusion experiments, but they nonetheless suffer from a relatively high failure rate when operated at high magnetic field strengths for long times. This is therefore a significant concern for long-pulse, high-field experiments such as Wendelstein 7-X (W7-X) and ITER. The new design is much more robust. The improvement is to use a LaB6 crystal instead of a tungsten wire as the thermionic emitter of electrons in the gauge. Such a LaB6 prototype gauge was successfully operated for a total of 60 h in B = 3.1 T, confirming the significantly improved robustness of the new design and qualifying it for near-term operation in W7-X. With the LaB6 crystal, an order of magnitude reduction in heating current is achieved, relative to the tungsten filament based gauges, from 15-20 A to 1-2 A. This reduces the Lorenz forces and the heating power by an order of magnitude also and is presumably the reason for the much improved robustness. The new gauge design, test environment setup at the superconducting magnet, and results from test operation are described.
Self-dual configurations in Abelian Higgs models with k-generalized gauge field dynamics
Energy Technology Data Exchange (ETDEWEB)
Casana, R.; Cavalcante, A. [Departamento de Física, Universidade Federal do Maranhão,65080-805, São Luís, Maranhão (Brazil); Hora, E. da [Departamento de Física, Universidade Federal do Maranhão,65080-805, São Luís, Maranhão (Brazil); Coordenadoria Interdisciplinar de Ciência e Tecnologia, Universidade Federal do Maranhão,65080-805, São Luís, Maranhão (Brazil)
2016-12-14
We have shown the existence of self-dual solutions in new Maxwell-Higgs scenarios where the gauge field possesses a k-generalized dynamic, i.e., the kinetic term of gauge field is a highly nonlinear function of F{sub μν}F{sup μν}. We have implemented our proposal by means of a k-generalized model displaying the spontaneous symmetry breaking phenomenon. We implement consistently the Bogomol’nyi-Prasad-Sommerfield formalism providing highly nonlinear self-dual equations whose solutions are electrically neutral possessing total energy proportional to the magnetic flux. Among the infinite set of possible configurations, we have found families of k-generalized models whose self-dual equations have a form mathematically similar to the ones arising in the Maxwell-Higgs or Chern-Simons-Higgs models. Furthermore, we have verified that our proposal also supports infinite twinlike models with |ϕ|{sup 4}-potential or |ϕ|{sup 6}-potential. With the aim to show explicitly that the BPS equations are able to provide well-behaved configurations, we have considered a test model in order to study axially symmetric vortices. By depending of the self-dual potential, we have shown that the k-generalized model is able to produce solutions that for long distances have a exponential decay (as Abrikosov-Nielsen-Olesen vortices) or have a power-law decay (characterizing delocalized vortices). In all cases, we observe that the generalization modifies the vortex core size, the magnetic field amplitude and the bosonic masses but the total energy remains proportional to the quantized magnetic flux.
Collective modes of the Nambu--Jona-Lasinio model with an external U(1) gauge field
International Nuclear Information System (INIS)
Klevansky, S.P.; Jaenicke, J.; Lemmer, R.H.
1991-01-01
The effect of external color fields on the collective modes of the SU L (2)xSU R (2) chiral flavor version of the Nambu--Jona-Lasinio model is studied analytically in a U(1) approximation to the gauge fields. We show that the scalar and pseudoscalar modes respond differently to external chromomagnetic and -electric fields. In the former case, in which chiral asymmetry is enhanced, the modes remain well separated and vary slowly with the field, while in the latter case the scalar mode drops rapidly to become degenerate with the pseudoscalar mode in the chiral limit. In this regime, both modes are weakly coupled to quark matter, and the pseudoscalar pion mode in particular survives as a well-defined excitation as it enters the pair continuum. The Goldberger-Treiman relation, which is shown to hold in the presence of external fields, is responsible for this behavior. Chromoelectric and -magnetic polarizabilities are seen to be equal and opposite with absolute values β σ =2.0α s and β π =0.03α s for the scalar and pseudoscalar modes respectively
Unexpected behavior of an order parameter for lattice gauge theories with matter fields
International Nuclear Information System (INIS)
Meyer, H.
1983-07-01
I consider a slightly modified definition of an order parameter that was recently suggested by DeTar and McLerran. It is supposed to test for confinement in lattice gauge theories when arbitrary matter fields are present, at finite physical temperature β -1 > 0. Its definition is quite directly related to confinement in the sense that no physical states with fractional baryon number can be observed. We test the parameter for different ranges of the coupling constants in the Z(2) Higgs model, whose phase structure is well known at zero temperature. It is found that the order parameter always shows the behavior characteristic of confinement, for all values of the coupling constants and arbitrary nonzero temperature. (orig.)
Field-theoretic methods in strongly-coupled models of general gauge mediation
International Nuclear Information System (INIS)
Fortin, Jean-François; Stergiou, Andreas
2013-01-01
An often-exploited feature of the operator product expansion (OPE) is that it incorporates a splitting of ultraviolet and infrared physics. In this paper we use this feature of the OPE to perform simple, approximate computations of soft masses in gauge-mediated supersymmetry breaking. The approximation amounts to truncating the OPEs for hidden-sector current–current operator products. Our method yields visible-sector superpartner spectra in terms of vacuum expectation values of a few hidden-sector IR elementary fields. We manage to obtain reasonable approximations to soft masses, even when the hidden sector is strongly coupled. We demonstrate our techniques in several examples, including a new framework where supersymmetry breaking arises both from a hidden sector and dynamically. Our results suggest that strongly-coupled models of supersymmetry breaking are naturally split
Field-theoretic Methods in Strongly-Coupled Models of General Gauge Mediation
Fortin, Jean-Francois
2013-01-01
An often-exploited feature of the operator product expansion (OPE) is that it incorporates a splitting of ultraviolet and infrared physics. In this paper we use this feature of the OPE to perform simple, approximate computations of soft masses in gauge-mediated supersymmetry breaking. The approximation amounts to truncating the OPEs for hidden-sector current-current operator products. Our method yields visible-sector superpartner spectra in terms of vacuum expectation values of a few hidden-sector IR elementary fields. We manage to obtain reasonable approximations to soft masses, even when the hidden sector is strongly coupled. We demonstrate our techniques in several examples, including a new framework where supersymmetry-breaking arises both from a hidden sector and dynamically.
Classical field theory on electrodynamics, non-abelian gauge theories and gravitation
Scheck, Florian
2018-01-01
Scheck’s successful textbook presents a comprehensive treatment, ideally suited for a one-semester course. The textbook describes Maxwell's equations first in their integral, directly testable form, then moves on to their local formulation. The first two chapters cover all essential properties of Maxwell's equations, including their symmetries and their covariance in a modern notation. Chapter 3 is devoted to Maxwell's theory as a classical field theory and to solutions of the wave equation. Chapter 4 deals with important applications of Maxwell's theory. It includes topical subjects such as metamaterials with negative refraction index and solutions of Helmholtz' equation in paraxial approximation relevant for the description of laser beams. Chapter 5 describes non-Abelian gauge theories from a classical, geometric point of view, in analogy to Maxwell's theory as a prototype, and culminates in an application to the U(2) theory relevant for electroweak interactions. The last chapter 6 gives a concise summary...
Renormalization and scaling behavior of non-Abelian gauge fields in curved spacetime
International Nuclear Information System (INIS)
Leen, T.K.
1983-01-01
In this article we discuss the one loop renormalization and scaling behavior of non-Abelian gauge field theories in a general curved spacetime. A generating functional is constructed which forms the basis for both the perturbation expansion and the Ward identifies. Local momentum space representations for the vector and ghost particles are developed and used to extract the divergent parts of Feynman integrals. The one loop diagram for the ghost propagator and the vector-ghost vertex are shown to have no divergences not present in Minkowski space. The Ward identities insure that this is true for the vector propagator as well. It is shown that the above renormalizations render the three- and four-vector vertices finite. Finally, a renormalization group equation valid in curved spacetimes is derived. Its solution is given and the theory is shown to be asymptotically free as in Minkowski space
Energy Technology Data Exchange (ETDEWEB)
Li, Detian; Cheng, Yongjun [Science and Technology on Vacuum Technology and Physics Laboratory, Lanzhou Institute of Physics, Lanzhou 730000 (China); Wang, Yongjun, E-mail: wyjlxlz@163.com [Science and Technology on Vacuum Technology and Physics Laboratory, Lanzhou Institute of Physics, Lanzhou 730000 (China); Zhang, Huzhong [Science and Technology on Vacuum Technology and Physics Laboratory, Lanzhou Institute of Physics, Lanzhou 730000 (China); Dong, Changkun [Institute of Micro-Nano Structures and Optoelectronics, Wenzhou University, Wenzhou 325035 (China); Li, Da [Division of Advanced Nanomaterials, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215125 (China)
2016-03-01
Graphical abstract: - Highlights: • The high quality CNT arrays were successfully grown on conductive stainless steel substrates. • The CNT array grown on stainless steel substrate exhibited superior field emission properties. • A high vacuum level about 10–8 Pa was measured by resultant CNT-based ionization gauge. • The ionization gauge with CNT cathode demonstrated a high stability. - Abstract: Vertically aligned carbon nanotube (CNT) arrays were fabricated by chemical vapor deposition (CVD) technique on different substrates. Microstructures and field emission characteristics of the as-grown CNT arrays were investigated systematically, and its application in ionization gauge was also evaluated preliminarily. The results indicate that the as-grown CNT arrays are vertically well-aligned relating to the substrate surfaces, but the CNTs grown on stainless steel substrate are longer and more crystalline than the ones grown on silicon wafer substrate. The field emission behaviors of the as-grown CNT arrays are strongly dependent upon substrate properties. Namely, the CNT array grown on stainless steel substrate has better field emission properties, including lower turn on and threshold fields, better emission stability and repeatability, compared with the one grown on silicon wafer substrate. The superior field emission properties of the CNT array grown on stainless steel substrate are mainly attributed to low contact resistance, high thermal conductivity, good adhesion strength, etc. In addition, the metrological behaviors of ionization gauge with the CNT array grown on stainless steel substrate as an electron source were investigated, and this novel cathode ionization gauge extends the lower limit of linear pressure measurement to 10{sup −8} Pa, which is one order of magnitude lower than the result reported for the same of gauge with CNT cathode.
Theoretical Maxwell's Equations, Gauge Field and Their Universality Based on One Conservation Law
Institute of Scientific and Technical Information of China (English)
Liu Changmao
2005-01-01
The notion of the inner product of vectors is extended to tensors of different orders, which may replace the vector product usually. The essences of the differential and the codifferential forms are pointed out: they represent the tangent surface and the normal surface fluxes of a tensor, respectively. The definitions of the divergence and the curl of a 2D surface flux of a tensor are obtained.Maxwell's equations, namely, the construction law of field, which were usually established based on two conservation laws of electric charge and imaginary magnetic charge, are derived by the author only by using one conservation law ( mass or fluid flux quantity and so on) and the feature of central field ( or its composition). By the feature of central field ( or its composition), the curl of 2D flux is zero. Both universality of gauge field and the difficulty of magnetic monopole theory ( a magnetic monopole has no effect on electric current just like a couple basing no effect on the sum of forces) are presented: magnetic monopole has no the feature of magnet. Finally it is pointed out that the base of relation of mass and energy is already involved in Maxwell's equations.
Bernabé Ferreira, Miguel Jorge; Ibieta Jimenez, Juan Pablo; Padmanabhan, Pramod; Teôtonio Sobrinho, Paulo
2015-12-01
State sum constructions, such as Kuperberg’s algorithm, give partition functions of physical systems, like lattice gauge theories, in various dimensions by associating local tensors or weights with different parts of a closed triangulated manifold. Here we extend this construction by including matter fields to build partition functions in both two and three space-time dimensions. The matter fields introduce new weights to the vertices and they correspond to Potts spin configurations described by an {A}-module with an inner product. Performing this construction on a triangulated manifold with a boundary we obtain transfer matrices which are decomposed into a product of local operators acting on vertices, links and plaquettes. The vertex and plaquette operators are similar to the ones appearing in the quantum double models (QDMs) of Kitaev. The link operator couples the gauge and the matter fields, and it reduces to the usual interaction terms in known models such as {{{Z}}}2 gauge theory with matter fields. The transfer matrices lead to Hamiltonians that are frustration-free and are exactly solvable. According to the choice of the initial input, that of the gauge group and a matter module, we obtain interesting models which have a new kind of ground state degeneracy that depends on the number of equivalence classes in the matter module under gauge action. Some of the models have confined flux excitations in the bulk which become deconfined at the surface. These edge modes are protected by an energy gap provided by the link operator. These properties also appear in ‘confined Walker-Wang’ models which are 3D models having interesting surface states. Apart from the gauge excitations there are also excitations in the matter sector which are immobile and can be thought of as defects like in the Ising model. We only consider bosonic matter fields in this paper.
Li, Detian; Cheng, Yongjun; Wang, Yongjun; Zhang, Huzhong; Dong, Changkun; Li, Da
2016-03-01
Vertically aligned carbon nanotube (CNT) arrays were fabricated by chemical vapor deposition (CVD) technique on different substrates. Microstructures and field emission characteristics of the as-grown CNT arrays were investigated systematically, and its application in ionization gauge was also evaluated preliminarily. The results indicate that the as-grown CNT arrays are vertically well-aligned relating to the substrate surfaces, but the CNTs grown on stainless steel substrate are longer and more crystalline than the ones grown on silicon wafer substrate. The field emission behaviors of the as-grown CNT arrays are strongly dependent upon substrate properties. Namely, the CNT array grown on stainless steel substrate has better field emission properties, including lower turn on and threshold fields, better emission stability and repeatability, compared with the one grown on silicon wafer substrate. The superior field emission properties of the CNT array grown on stainless steel substrate are mainly attributed to low contact resistance, high thermal conductivity, good adhesion strength, etc. In addition, the metrological behaviors of ionization gauge with the CNT array grown on stainless steel substrate as an electron source were investigated, and this novel cathode ionization gauge extends the lower limit of linear pressure measurement to 10-8 Pa, which is one order of magnitude lower than the result reported for the same of gauge with CNT cathode.
A New Self-Constrained Inversion Method of Potential Fields Based on Probability Tomography
Sun, S.; Chen, C.; WANG, H.; Wang, Q.
2014-12-01
The self-constrained inversion method of potential fields uses a priori information self-extracted from potential field data. Differing from external a priori information, the self-extracted information are generally parameters derived exclusively from the analysis of the gravity and magnetic data (Paoletti et al., 2013). Here we develop a new self-constrained inversion method based on probability tomography. Probability tomography doesn't need any priori information, as well as large inversion matrix operations. Moreover, its result can describe the sources, especially the distribution of which is complex and irregular, entirely and clearly. Therefore, we attempt to use the a priori information extracted from the probability tomography results to constrain the inversion for physical properties. The magnetic anomaly data was taken as an example in this work. The probability tomography result of magnetic total field anomaly(ΔΤ) shows a smoother distribution than the anomalous source and cannot display the source edges exactly. However, the gradients of ΔΤ are with higher resolution than ΔΤ in their own direction, and this characteristic is also presented in their probability tomography results. So we use some rules to combine the probability tomography results of ∂ΔΤ⁄∂x, ∂ΔΤ⁄∂y and ∂ΔΤ⁄∂z into a new result which is used for extracting a priori information, and then incorporate the information into the model objective function as spatial weighting functions to invert the final magnetic susceptibility. Some magnetic synthetic examples incorporated with and without a priori information extracted from the probability tomography results were made to do comparison, results of which show that the former are more concentrated and with higher resolution of the source body edges. This method is finally applied in an iron mine in China with field measured ΔΤ data and performs well. ReferencesPaoletti, V., Ialongo, S., Florio, G., Fedi, M
Franklin Medal and Bower prize awarded to C.N. Yang. On the Yang-Mills gauge field theory
International Nuclear Information System (INIS)
Ma Zhongqi
1995-01-01
C.N. Yang was awarded the Benjamin Franklin Medal and 1995 Bower Prize mainly for his fundamental work on nonabelian gauge field theory. A brief introduction to this theory and its important role in the development of physics is given
Wang, Juven C; Gu, Zheng-Cheng; Wen, Xiao-Gang
2015-01-23
The challenge of identifying symmetry-protected topological states (SPTs) is due to their lack of symmetry-breaking order parameters and intrinsic topological orders. For this reason, it is impossible to formulate SPTs under Ginzburg-Landau theory or probe SPTs via fractionalized bulk excitations and topology-dependent ground state degeneracy. However, the partition functions from path integrals with various symmetry twists are universal SPT invariants, fully characterizing SPTs. In this work, we use gauge fields to represent those symmetry twists in closed spacetimes of any dimensionality and arbitrary topology. This allows us to express the SPT invariants in terms of continuum field theory. We show that SPT invariants of pure gauge actions describe the SPTs predicted by group cohomology, while the mixed gauge-gravity actions describe the beyond-group-cohomology SPTs. We find new examples of mixed gauge-gravity actions for U(1) SPTs in (4+1)D via the gravitational Chern-Simons term. Field theory representations of SPT invariants not only serve as tools for classifying SPTs, but also guide us in designing physical probes for them. In addition, our field theory representations are independently powerful for studying group cohomology within the mathematical context.
de Brito, P. E.; Nazareno, H. N.
2007-01-01
In the present work we treat the problem of a particle in a uniform magnetic field along the symmetric gauge, so chosen since the wavefunctions present the required cylindrical symmetry. It is our understanding that by means of this work we can make a contribution to the teaching of the present subject, as well as encourage students to use…
An alternative prescription for Gauging Floreanini-Jackiw chiral bosons
International Nuclear Information System (INIS)
Dias, S.A.; Souza Dutra, A. de.
1991-01-01
We seek new couplings of chiral bosons to U (1) gauge fields. Lorentz covariance of the resulting constrained Lagrangian is checked with the help of a procedure based in the first-order formalism of Faddeev and Jackiw. We find Harada's constraint and another local one not previously considered, besides infinite non-local couplings.We analyze the constraint structure and part of the spectrum of this second solution and show that it is equivalent to an explicitly covariant coupling of Siegel's chiral boson to gauge fields, which preserves chirality under gauge transformations. (author)
The role of gauge fields in cold and dense quark matter
Energy Technology Data Exchange (ETDEWEB)
Noronha, J
2007-07-01
In this thesis we investigate the role played by gauge fields in providing new observable signatures that can attest to the presence of color superconductivity in neutron stars. We show that thermal gluon fluctuations in color-flavor locked superconductors can substantially increase their critical temperature and also change the order of the transition, which becomes a strong first-order phase transition. Moreover, we explore the effects of strong magnetic fields on the properties of color-flavor locked superconducting matter. We find that both the energy gaps as well as the magnetization are oscillating functions of the magnetic field. Also, it is shown that the magnetization can be so strong that homogeneous quark matter becomes metastable for a range of parameters. This points towards the existence of magnetic domains or other types of magnetic inhomogeneities in the hypothesized quark cores of magnetars. Obviously, our results only apply if the strong magnetic fields observed on the surface of magnetars can be transmitted to their inner core. This can occur if the superconducting protons expected to exist in the outer core form a type-II superconductor. However, it has been argued that the observed long periodic oscillations in isolated pulsars can only be explained if the outer core is a type-I superconductor rather than type-II. We show that this is not the only solution for the precession puzzle by demonstrating that the long-term variation in the spin of PSR 1828-11 can be explained in terms of Tkachenko oscillations within superfluid shells. (orig.)
The role of gauge fields in cold and dense quark matter
International Nuclear Information System (INIS)
Noronha, J.
2007-01-01
In this thesis we investigate the role played by gauge fields in providing new observable signatures that can attest to the presence of color superconductivity in neutron stars. We show that thermal gluon fluctuations in color-flavor locked superconductors can substantially increase their critical temperature and also change the order of the transition, which becomes a strong first-order phase transition. Moreover, we explore the effects of strong magnetic fields on the properties of color-flavor locked superconducting matter. We find that both the energy gaps as well as the magnetization are oscillating functions of the magnetic field. Also, it is shown that the magnetization can be so strong that homogeneous quark matter becomes metastable for a range of parameters. This points towards the existence of magnetic domains or other types of magnetic inhomogeneities in the hypothesized quark cores of magnetars. Obviously, our results only apply if the strong magnetic fields observed on the surface of magnetars can be transmitted to their inner core. This can occur if the superconducting protons expected to exist in the outer core form a type-II superconductor. However, it has been argued that the observed long periodic oscillations in isolated pulsars can only be explained if the outer core is a type-I superconductor rather than type-II. We show that this is not the only solution for the precession puzzle by demonstrating that the long-term variation in the spin of PSR 1828-11 can be explained in terms of Tkachenko oscillations within superfluid shells. (orig.)
Classical field theory. On electrodynamics, non-Abelian gauge theories and gravitation. 2. ed.
Energy Technology Data Exchange (ETDEWEB)
Scheck, Florian
2018-04-01
Scheck's successful textbook presents a comprehensive treatment, ideally suited for a one-semester course. The textbook describes Maxwell's equations first in their integral, directly testable form, then moves on to their local formulation. The first two chapters cover all essential properties of Maxwell's equations, including their symmetries and their covariance in a modern notation. Chapter 3 is devoted to Maxwell's theory as a classical field theory and to solutions of the wave equation. Chapter 4 deals with important applications of Maxwell's theory. It includes topical subjects such as metamaterials with negative refraction index and solutions of Helmholtz' equation in paraxial approximation relevant for the description of laser beams. Chapter 5 describes non-Abelian gauge theories from a classical, geometric point of view, in analogy to Maxwell's theory as a prototype, and culminates in an application to the U(2) theory relevant for electroweak interactions. The last chapter 6 gives a concise summary of semi-Riemannian geometry as the framework for the classical field theory of gravitation. The chapter concludes with a discussion of the Schwarzschild solution of Einstein's equations and the classical tests of general relativity. The new concept of this edition presents the content divided into two tracks: the fast track for master's students, providing the essentials, and the intensive track for all wanting to get in depth knowledge of the field. Cleary labeled material and sections guide students through the preferred level of treatment. Numerous problems and worked examples will provide successful access to Classical Field Theory.
Wan, Xiaoqing; Zhao, Chunhui
2017-06-01
As a competitive machine learning algorithm, the stacked sparse autoencoder (SSA) has achieved outstanding popularity in exploiting high-level features for classification of hyperspectral images (HSIs). In general, in the SSA architecture, the nodes between adjacent layers are fully connected and need to be iteratively fine-tuned during the pretraining stage; however, the nodes of previous layers further away may be less likely to have a dense correlation to the given node of subsequent layers. Therefore, to reduce the classification error and increase the learning rate, this paper proposes the general framework of locally connected SSA; that is, the biologically inspired local receptive field (LRF) constrained SSA architecture is employed to simultaneously characterize the local correlations of spectral features and extract high-level feature representations of hyperspectral data. In addition, the appropriate receptive field constraint is concurrently updated by measuring the spatial distances from the neighbor nodes to the corresponding node. Finally, the efficient random forest classifier is cascaded to the last hidden layer of the SSA architecture as a benchmark classifier. Experimental results on two real HSI datasets demonstrate that the proposed hierarchical LRF constrained stacked sparse autoencoder and random forest (SSARF) provides encouraging results with respect to other contrastive methods, for instance, the improvements of overall accuracy in a range of 0.72%-10.87% for the Indian Pines dataset and 0.74%-7.90% for the Kennedy Space Center dataset; moreover, it generates lower running time compared with the result provided by similar SSARF based methodology.
Background field method in gauge theories and on linear sigma models
International Nuclear Information System (INIS)
van de Ven, A.E.M.
1986-01-01
This dissertation constitutes a study of the ultraviolet behavior of gauge theories and two-dimensional nonlinear sigma-models by means of the background field method. After a general introduction in chapter 1, chapter 2 presents algorithms which generate the divergent terms in the effective action at one-loop for arbitrary quantum field theories in flat spacetime of dimension d ≤ 11. It is demonstrated that global N = 1 supersymmetric Yang-Mills theory in six dimensions in one-loop UV-finite. Chapter 3 presents an algorithm which produces the divergent terms in the effective action at two-loops for renormalizable quantum field theories in a curved four-dimensional background spacetime. Chapter 4 presents a study of the two-loop UV-behavior of two-dimensional bosonic and supersymmetric non-linear sigma-models which include a Wess-Zumino-Witten term. It is found that, to this order, supersymmetric models on quasi-Ricci flat spaces are UV-finite and the β-functions for the bosonic model depend only on torsionful curvatures. Chapter 5 summarizes a superspace calculation of the four-loop β-function for two-dimensional N = 1 and N = 2 supersymmetric non-linear sigma-models. It is found that besides the one-loop contribution which vanishes on Ricci-flat spaces, the β-function receives four-loop contributions which do not vanish in the Ricci-flat case. Implications for superstrings are discussed. Chapters 6 and 7 treat the details of these calculations
International Nuclear Information System (INIS)
Wundt, B.J.; Jentschura, U.D.
2012-01-01
We investigate the coupling of the electromagnetic sources (charge and current densities) to the scalar and vector potentials in classical electrodynamics, using Green function techniques. As is well known, the scalar potential shows an action-at-a-distance behavior in Coulomb gauge. The conundrum generated by the instantaneous interaction has intrigued physicists for a long time. Starting from the differential equations that couple the sources to the potentials, we here show in a concise derivation, using the retarded Green function, how the instantaneous interaction cancels in the calculation of the electric field. The time derivative of a specific additional term in the vector potential, present only in Coulomb gauge, yields a supplementary contribution to the electric field which cancels the gradient of the instantaneous Coulomb gauge scalar potential, as required by gauge invariance. This completely eliminates the contribution of the instantaneous interaction from the electric field. It turns out that a careful formulation of the retarded Green function, inspired by field theory, is required in order to correctly treat boundary terms in partial integrations. Finally, compact integral representations are derived for the Liénard–Wiechert potentials (scalar and vector) in Coulomb gauge which manifestly contain two compensating action-at-a-distance terms. - Highlights: ► We investigate action-at-a-distance effects in electrodynamics in detail. ► We calculate the instantaneous interactions for scalar and vector potentials. ► The cancellation mechanism involves the retarded Green function. ► The mechanism is confirmed on the example of moving point charges. ► The Green function has to be treated with care for nontrivial boundary terms.
A Modified FCM Classifier Constrained by Conditional Random Field Model for Remote Sensing Imagery
Directory of Open Access Journals (Sweden)
WANG Shaoyu
2016-12-01
Full Text Available Remote sensing imagery has abundant spatial correlation information, but traditional pixel-based clustering algorithms don't take the spatial information into account, therefore the results are often not good. To this issue, a modified FCM classifier constrained by conditional random field model is proposed. Adjacent pixels' priori classified information will have a constraint on the classification of the center pixel, thus extracting spatial correlation information. Spectral information and spatial correlation information are considered at the same time when clustering based on second order conditional random field. What's more, the global optimal inference of pixel's classified posterior probability can be get using loopy belief propagation. The experiment shows that the proposed algorithm can effectively maintain the shape feature of the object, and the classification accuracy is higher than traditional algorithms.
Lim, Yeunhwan; Holt, Jeremy W.
2017-06-01
We investigate the structure of neutron star crusts, including the crust-core boundary, based on new Skyrme mean field models constrained by the bulk-matter equation of state from chiral effective field theory and the ground-state energies of doubly-magic nuclei. Nuclear pasta phases are studied using both the liquid drop model as well as the Thomas-Fermi approximation. We compare the energy per nucleon for each geometry (spherical nuclei, cylindrical nuclei, nuclear slabs, cylindrical holes, and spherical holes) to obtain the ground state phase as a function of density. We find that the size of the Wigner-Seitz cell depends strongly on the model parameters, especially the coefficients of the density gradient interaction terms. We employ also the thermodynamic instability method to check the validity of the numerical solutions based on energy comparisons.
Anomalous triple gauge couplings in the effective field theory approach at the LHC
Energy Technology Data Exchange (ETDEWEB)
Falkowski, Adam [Laboratoire de Physique Théorique,Bat. 210, Université Paris-Sud, 91405 Orsay (France); González-Alonso, Martín [IPN de Lyon/CNRS,Universite Lyon 1, Villeurbanne (France); Greljo, Admir [Physik-Institut, Universität Zürich,CH-8057 Zürich (Switzerland); Faculty of Science, University of Sarajevo,Zmaja od Bosne 33-35, 71000 Sarajevo (Bosnia and Herzegovina); Marzocca, David [Physik-Institut, Universität Zürich,CH-8057 Zürich (Switzerland); Son, Minho [Department of Physics, Korea Advanced Institute of Science and Technology,291 Daehak-ro, Yuseong-gu, Daejeon 34141 (Korea, Republic of)
2017-02-22
We discuss how to perform consistent extractions of anomalous triple gauge couplings (aTGC) from electroweak boson pair production at the LHC in the Standard Model Effective Field Theory (SMEFT). After recasting recent ATLAS and CMS searches in pp→WZ(WW)→ℓ{sup ′}νℓ{sup +}ℓ{sup −}(ν{sub ℓ}) channels, we find that: (a) working consistently at order Λ{sup −2} in the SMEFT expansion the existing aTGC bounds from Higgs and LEP-2 data are not improved, (b) the strong limits quoted by the experimental collaborations are due to the partial Λ{sup −4} corrections (dimension-6 squared contributions). Using helicity selection rule arguments we are able to explain the suppression in some of the interference terms, and discuss conditions on New Physics (NP) models that can benefit from such LHC analyses. Furthermore, standard analyses assume implicitly a quite large NP scale, an assumption that can be relaxed by imposing cuts on the underlying scale of the process (√(ŝ)). In practice, we find almost no correlation between √(ŝ) and the experimentally accessible quantities, which complicates the SMEFT interpretation. Nevertheless, we provide a method to set (conservative) aTGC bounds in this situation, and recast the present searches accordingly. Finally, we introduce a simple NP model for aTGC to compare the bounds obtained directly in the model with those from the SMEFT analysis.
Holomorphic field realization of SH"c and quantum geometry of quiver gauge theories
International Nuclear Information System (INIS)
Bourgine, Jean-Emile; Matsuo, Yutaka; Zhang, Hong
2016-01-01
In the context of 4D/2D dualities, SH"c algebra, introduced by Schiffmann and Vasserot, provides a systematic method to analyse the instanton partition functions of N=2 supersymmetric gauge theories. In this paper, we rewrite the SH"c algebra in terms of three holomorphic fields D_0(z), D_±_1(z) with which the algebra and its representations are simplified. The instanton partition functions for arbitrary N=2 super Yang-Mills theories with A_n and A_n"("1") type quiver diagrams are compactly expressed as a product of four building blocks, Gaiotto state, dilatation, flavor vertex operator and intertwiner which are written in terms of SH"c and the orthogonal basis introduced by Alba, Fateev, Litvinov and Tarnopolskiy. These building blocks are characterized by new conditions which generalize the known ones on the Gaiotto state and the Carlsson-Okounkov vertex. Consistency conditions of the inner product give algebraic relations for the chiral ring generating functions defined by Nekrasov, Pestun and Shatashvili. In particular we show the polynomiality of the qq-characters which have been introduced as a deformation of the Yangian characters. These relations define a second quantization of the Seiberg-Witten geometry, and, accordingly, reduce to a Baxter TQ-equation in the Nekrasov-Shatashvili limit of the Omega-background.
Constraining the interior density profile of a Jovian planet from precision gravity field data
Movshovitz, Naor; Fortney, Jonathan J.; Helled, Ravit; Hubbard, William B.; Thorngren, Daniel; Mankovich, Chris; Wahl, Sean; Militzer, Burkhard; Durante, Daniele
2017-10-01
The external gravity field of a planetary body is determined by the distribution of mass in its interior. Therefore, a measurement of the external field, properly interpreted, tells us about the interior density profile, ρ(r), which in turn can be used to constrain the composition in the interior and thereby learn about the formation mechanism of the planet. Planetary gravity fields are usually described by the coefficients in an expansion of the gravitational potential. Recently, high precision measurements of these coefficients for Jupiter and Saturn have been made by the radio science instruments on the Juno and Cassini spacecraft, respectively.The resulting coefficients come with an associated uncertainty. And while the task of matching a given density profile with a given set of gravity coefficients is relatively straightforward, the question of how best to account for the uncertainty is not. In essentially all prior work on matching models to gravity field data, inferences about planetary structure have rested on imperfect knowledge of the H/He equation of state and on the assumption of an adiabatic interior. Here we wish to vastly expand the phase space of such calculations. We present a framework for describing all the possible interior density structures of a Jovian planet, constrained only by a given set of gravity coefficients and their associated uncertainties. Our approach is statistical. We produce a random sample of ρ(a) curves drawn from the underlying (and unknown) probability distribution of all curves, where ρ is the density on an interior level surface with equatorial radius a. Since the resulting set of density curves is a random sample, that is, curves appear with frequency proportional to the likelihood of their being consistent with the measured gravity, we can compute probability distributions for any quantity that is a function of ρ, such as central pressure, oblateness, core mass and radius, etc. Our approach is also bayesian, in that
Tews, I.; Carlson, J.; Gandolfi, S.; Reddy, S.
2018-06-01
The dense matter equation of state (EOS) determines neutron star (NS) structure but can be calculated reliably only up to one to two times the nuclear saturation density, using accurate many-body methods that employ nuclear interactions from chiral effective field theory constrained by scattering data. In this work, we use physically motivated ansatzes for the speed of sound c S at high density to extend microscopic calculations of neutron-rich matter to the highest densities encountered in stable NS cores. We show how existing and expected astrophysical constraints on NS masses and radii from X-ray observations can constrain the speed of sound in the NS core. We confirm earlier expectations that c S is likely to violate the conformal limit of {c}S2≤slant {c}2/3, possibly reaching values closer to the speed of light c at a few times the nuclear saturation density, independent of the nuclear Hamiltonian. If QCD obeys the conformal limit, we conclude that the rapid increase of c S required to accommodate a 2 M ⊙ NS suggests a form of strongly interacting matter where a description in terms of nucleons will be unwieldy, even between one and two times the nuclear saturation density. For typical NSs with masses in the range of 1.2–1.4 M ⊙, we find radii between 10 and 14 km, and the smallest possible radius of a 1.4 M ⊙ NS consistent with constraints from nuclear physics and observations is 8.4 km. We also discuss how future observations could constrain the EOS and guide theoretical developments in nuclear physics.
International Nuclear Information System (INIS)
Gogala, B.
1983-01-01
The equations of the gauge theory of gravitation are derived from a complex quadratic Lagrangian with torsion. The derivation is performed in a coordinate basis in a completely covariant way. (author)
International Nuclear Information System (INIS)
Naito, S.
1976-01-01
We derive commutation relations (CR's) between gauge-invariant quantities in the Yang-Mills field theory by applying the Peierls method. The CR's obtained are different from those given by Mandelstam in his gauge-independent, path-dependent formalism. However, our CR's are shown to give a consistently quantized field theory, while his CR's do not. In fact, there exist systematic errors in Mandelstam's treatment of the covariant Green's functions. On the other hand, if we correctly treat covariant Green's functions guided by his procedure, our CR's are shown to lead to the same Feynman rules for the Yang-Mills field as prescribed by Feynman, DeWitt, Faddeev and Popov, and Mandelstam
Anyons, spin, and statistics in (2+1)-dimensional U(1)-scalar Chern-Simons gauge field theory
International Nuclear Information System (INIS)
Graziano, E.; Rothe, K.D.
1994-01-01
We present a detailed analysis of the quantum field theory of a Chern-Simons field coupled minimally to massive charged bosonic matter. This analysis is carried out in the Coulomb and covariant gauges. Some aspects concerning the transformation law of the fields under Poincare transformations are clarified. Emphasis is placed on gauge-invariant operators. The order and disorder operators are constructed from their dual algebra. The order operator is shown to obey anyonic statistics. The correlator of the disorder operator is computed in the large boson-mass limit, and the corresponding cluster properties are discussed. In the absence of a symmetry-breaking Higgs potential, there is no evidence for the ground state being anyonic
Modeling and Simulation of the Gonghe geothermal field (Qinghai, China) Constrained by Geophysical
Zeng, Z.; Wang, K.; Zhao, X.; Huai, N.; He, R.
2017-12-01
The Gonghe geothermal field in Qinghai is important because of its variety of geothermal resource types. Now, the Gonghe geothermal field has been a demonstration area of geothermal development and utilization in China. It has been the topic of numerous geophysical investigations conducted to determine the depth to and the nature of the heat source, and to image the channel of heat flow. This work focuses on the causes of geothermal fields used numerical simulation method constrained by geophysical data. At first, by analyzing and inverting an magnetotelluric (MT) measurements profile across this area we obtain the deep resistivity distribution. Using the gravity anomaly inversion constrained by the resistivity profile, the density of the basins and the underlying rocks can be calculated. Combined with the measured parameters of rock thermal conductivity, the 2D geothermal conceptual model of Gonghe area is constructed. Then, the unstructured finite element method is used to simulate the heat conduction equation and the geothermal field. Results of this model were calibrated with temperature data for the observation well. A good match was achieved between the measured values and the model's predicted values. At last, geothermal gradient and heat flow distribution of this model are calculated(fig.1.). According to the results of geophysical exploration, there is a low resistance and low density region (d5) below the geothermal field. We recognize that this anomaly is generated by tectonic motion, and this tectonic movement creates a mantle-derived heat upstream channel. So that the anomalous basement heat flow values are higher than in other regions. The model's predicted values simulated using that boundary condition has a good match with the measured values. The simulated heat flow values show that the mantle-derived heat flow migrates through the boundary of the low-resistance low-density anomaly area to the Gonghe geothermal field, with only a small fraction
On the development of non-commutative translation-invariant quantum gauge field models
International Nuclear Information System (INIS)
Sedmik, R.I.P.
2009-01-01
Aiming to understand the most fundamental principles of nature one has to approach the highest possible energy scales corresponding to the smallest possible distances - the Planck scale. Historically, three different theoretical fields have been developed to treat the problems appearing in this endeavor: string theory, quantum gravity, and non-commutative (NC) quantum field theory (QFT). The latter was originally motivated by the conjecture that the introduction of uncertainty relations between space-time coordinates introduces a natural energy cutoff, which should render the resulting computations well defined and finite. Despite failing to fulfill this expectation, NC physics is a challenging field of research, which has proved to be a fruitful source for new ideas and methods. Mathematically, non-commutativity is implemented by the so called Weyl quantization, giving rise to a modified product - the Groenewold-Moyal product. It realizes an operator ordering, and allows to work within the well established framework of QFT on non-commutative spaces. The main obstacle of NCQFT is the appearance of singularities being shifted from high to low energies. This effect, being referred to as 'uV/IR mixing', is a direct consequence of the deformation of the product, and inhibits or complicates the direct application of well approved renormalization schemes. In order to remedy this problem, several approaches have been worked out during the past decade which, unfortunately, all have shortcomings such as the breaking of translation invariance or an inappropriate alternation of degrees of freedom. Thence, the resulting theories are either being rendered 'unphysical', or considered a priori to be toy models. Nonetheless, these efforts have helped to analyze the mechanisms leading to uV/IR mixing and finally led to the insight that renormalizability can only be achieved by respecting the inherent connection of long and short distances (scales) of NCQFT in the construction of
Movshovitz, N.; Fortney, J. J.; Helled, R.; Hubbard, W. B.; Mankovich, C.; Thorngren, D.; Wahl, S. M.; Militzer, B.; Durante, D.
2017-12-01
The external gravity field of a planetary body is determined by the distribution of mass in its interior. Therefore, a measurement of the external field, properlyinterpreted, tells us about the interior density profile, ρ(r), which in turn can be used to constrain the composition in the interior and thereby learn about theformation mechanism of the planet. Recently, very high precision measurements of the gravity coefficients for Saturn have been made by the radio science instrument on the Cassini spacecraft during its Grand Finale orbits. The resulting coefficients come with an associated uncertainty. The task of matching a given density profile to a given set of gravity coefficients is relatively straightforward, but the question of how to best account for the uncertainty is not. In essentially all prior work on matching models to gravity field data inferences about planetary structure have rested on assumptions regarding the imperfectly known H/He equation of state and the assumption of an adiabatic interior. Here we wish to vastly expand the phase space of such calculations. We present a framework for describing all the possible interior density structures of a Jovian planet constrained by a given set of gravity coefficients and their associated uncertainties. Our approach is statistical. We produce a random sample of ρ(a) curves drawn from the underlying (and unknown) probability distribution of all curves, where ρ is the density on an interior level surface with equatorial radius a. Since the resulting set of density curves is a random sample, that is, curves appear with frequency proportional to the likelihood of their being consistent with the measured gravity, we can compute probability distributions for any quantity that is a function of ρ, such as central pressure, oblateness, core mass and radius, etc. Our approach is also Bayesian, in that it can utilize any prior assumptions about the planet's interior, as necessary, without being overly
Constraining chameleon field theories using the GammeV afterglow experiments
International Nuclear Information System (INIS)
Upadhye, A.; Steffen, J.H.; Weltman, A.
2009-01-01
The GammeV experiment has constrained the couplings of chameleon scalar fields to matter and photons. Here we present a detailed calculation of the chameleon afterglow rate underlying these constraints. The dependence of GammeV constraints on various assumptions in the calculation is studied. We discuss GammeV-CHASE, a second-generation GammeV experiment, which will improve upon GammeV in several major ways. Using our calculation of the chameleon afterglow rate, we forecast model-independent constraints achievable by GammeV-CHASE. We then apply these constraints to a variety of chameleon models, including quartic chameleons and chameleon dark energy models. The new experiment will be able to probe a large region of parameter space that is beyond the reach of current tests, such as fifth force searches, constraints on the dimming of distant astrophysical objects, and bounds on the variation of the fine structure constant.
Constraining chameleon field theories using the GammeV afterglow experiments
International Nuclear Information System (INIS)
Upadhye, A.; Steffen, J. H.; Weltman, A.
2010-01-01
The GammeV experiment has constrained the couplings of chameleon scalar fields to matter and photons. Here, we present a detailed calculation of the chameleon afterglow rate underlying these constraints. The dependence of GammeV constraints on various assumptions in the calculation is studied. We discuss the GammeV-CHameleon Afterglow SEarch, a second-generation GammeV experiment, which will improve upon GammeV in several major ways. Using our calculation of the chameleon afterglow rate, we forecast model-independent constraints achievable by GammeV-CHameleon Afterglow SEarch. We then apply these constraints to a variety of chameleon models, including quartic chameleons and chameleon dark energy models. The new experiment will be able to probe a large region of parameter space that is beyond the reach of current tests, such as fifth force searches, constraints on the dimming of distant astrophysical objects, and bounds on the variation of the fine structure constant.
Hydrogen atom excitation in intense attosecond laser field: Gauge dependence of dipole approximation
Energy Technology Data Exchange (ETDEWEB)
Aldarmaa, Ch., E-mail: aldaraa2004@yahoo.com, E-mail: l-xemee@yahoo.com; Khenmedekh, L., E-mail: aldaraa2004@yahoo.com, E-mail: l-xemee@yahoo.com [Theoretical Physics and Simulation Group, School of Materials Technology, MUST (Mongolia); Lkhagva, O. [School of Physics and Electronics, NUM (Mongolia)
2014-03-24
It is assumed that, the atomic excitations probability can be calculated using first order perturbation theory and dipole approximations. The validity of the dipole approximations had been examined by comparing the results with the results obtained by exact calculations within the first order perturbation theory[2]. Figure 1 shows the time dependence of the transition probability in the dipole approximation. From these plots it is obvious that, the probabilities obtained in the length gauge are higher than that in the velocity gauge, in the interaction period (−τ/2
Gauging Metallicity of Diffuse Gas under an Uncertain Ionizing Radiation Field
Chen, Hsiao-Wen; Johnson, Sean D.; Zahedy, Fakhri S.; Rauch, Michael; Mulchaey, John S.
2017-06-01
Gas metallicity is a key quantity used to determine the physical conditions of gaseous clouds in a wide range of astronomical environments, including interstellar and intergalactic space. In particular, considerable effort in circumgalactic medium (CGM) studies focuses on metallicity measurements because gas metallicity serves as a critical discriminator for whether the observed heavy ions in the CGM originate in chemically enriched outflows or in more chemically pristine gas accreted from the intergalactic medium. However, because the gas is ionized, a necessary first step in determining CGM metallicity is to constrain the ionization state of the gas which, in addition to gas density, depends on the ultraviolet background radiation field (UVB). While it is generally acknowledged that both the intensity and spectral slope of the UVB are uncertain, the impact of an uncertain spectral slope has not been properly addressed in the literature. This Letter shows that adopting a different spectral slope can result in an order of magnitude difference in the inferred CGM metallicity. Specifically, a harder UVB spectrum leads to a higher estimated gas metallicity for a given set of observed ionic column densities. Therefore, such systematic uncertainties must be folded into the error budget for metallicity estimates of ionized gas. An initial study shows that empirical diagnostics are available for discriminating between hard and soft ionizing spectra. Applying these diagnostics helps reduce the systematic uncertainties in CGM metallicity estimates.
Gauging Metallicity of Diffuse Gas under an Uncertain Ionizing Radiation Field
Energy Technology Data Exchange (ETDEWEB)
Chen, Hsiao-Wen; Zahedy, Fakhri S. [Department of Astronomy and Astrophysics, The University of Chicago, 5640 S Ellis Avenue, Chicago, IL 60637 (United States); Johnson, Sean D. [Department of Astrophysics, Princeton University, Princeton, NJ (United States); Rauch, Michael; Mulchaey, John S., E-mail: hchen@oddjob.uchicago.edu [The Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
2017-06-20
Gas metallicity is a key quantity used to determine the physical conditions of gaseous clouds in a wide range of astronomical environments, including interstellar and intergalactic space. In particular, considerable effort in circumgalactic medium (CGM) studies focuses on metallicity measurements because gas metallicity serves as a critical discriminator for whether the observed heavy ions in the CGM originate in chemically enriched outflows or in more chemically pristine gas accreted from the intergalactic medium. However, because the gas is ionized, a necessary first step in determining CGM metallicity is to constrain the ionization state of the gas which, in addition to gas density, depends on the ultraviolet background radiation field (UVB). While it is generally acknowledged that both the intensity and spectral slope of the UVB are uncertain, the impact of an uncertain spectral slope has not been properly addressed in the literature. This Letter shows that adopting a different spectral slope can result in an order of magnitude difference in the inferred CGM metallicity. Specifically, a harder UVB spectrum leads to a higher estimated gas metallicity for a given set of observed ionic column densities. Therefore, such systematic uncertainties must be folded into the error budget for metallicity estimates of ionized gas. An initial study shows that empirical diagnostics are available for discriminating between hard and soft ionizing spectra. Applying these diagnostics helps reduce the systematic uncertainties in CGM metallicity estimates.
Primordial anisotropies in gauged hybrid inflation
Akbar Abolhasani, Ali; Emami, Razieh; Firouzjahi, Hassan
2014-05-01
We study primordial anisotropies generated in the model of gauged hybrid inflation in which the complex waterfall field is charged under a U(1)gauge field. Primordial anisotropies are generated either actively during inflation or from inhomogeneities modulating the surface of end of inflation during waterfall transition. We present a consistent δN mechanism to calculate the anisotropic power spectrum and bispectrum. We show that the primordial anisotropies generated at the surface of end of inflation do not depend on the number of e-folds and therefore do not produce dangerously large anisotropies associated with the IR modes. Furthermore, one can find the parameter space that the anisotropies generated from the surface of end of inflation cancel the anisotropies generated during inflation, therefore relaxing the constrains on model parameters imposed from IR anisotropies. We also show that the gauge field fluctuations induce a red-tilted power spectrum so the averaged power spectrum from the gauge field can change the total power spectrum from blue to red. Therefore, hybrid inflation, once gauged under a U(1) field, can be consistent with the cosmological observations.
Primordial anisotropies in gauged hybrid inflation
International Nuclear Information System (INIS)
Abolhasani, Ali Akbar; Emami, Razieh; Firouzjahi, Hassan
2014-01-01
We study primordial anisotropies generated in the model of gauged hybrid inflation in which the complex waterfall field is charged under a U(1)gauge field. Primordial anisotropies are generated either actively during inflation or from inhomogeneities modulating the surface of end of inflation during waterfall transition. We present a consistent δN mechanism to calculate the anisotropic power spectrum and bispectrum. We show that the primordial anisotropies generated at the surface of end of inflation do not depend on the number of e-folds and therefore do not produce dangerously large anisotropies associated with the IR modes. Furthermore, one can find the parameter space that the anisotropies generated from the surface of end of inflation cancel the anisotropies generated during inflation, therefore relaxing the constrains on model parameters imposed from IR anisotropies. We also show that the gauge field fluctuations induce a red-tilted power spectrum so the averaged power spectrum from the gauge field can change the total power spectrum from blue to red. Therefore, hybrid inflation, once gauged under a U(1) field, can be consistent with the cosmological observations
Energy Technology Data Exchange (ETDEWEB)
Kishore, P.; Ramesh, R.; Hariharan, K.; Kathiravan, C. [Indian Institute of Astrophysics, 2nd Block, Koramangala, Bangalore—560034 (India); Gopalswamy, N., E-mail: kishore@iiap.res.in [Code 671, Solar Physics Laboratory, NASA/GSFC, Greenbelt, MD 20771 (United States)
2016-11-20
We report on low-frequency radio (85–35 MHz) spectral observations of four different type II radio bursts, which exhibited fundamental-harmonic emission and split-band structure. Each of the bursts was found to be closely associated with a whitelight coronal mass ejection (CME) close to the Sun. We estimated the coronal magnetic field strength from the split-band characteristics of the bursts, by assuming a model for the coronal electron density distribution. The choice of the model was constrained, based on the following criteria: (1) when the radio burst is observed simultaneously in the upper and lower bands of the fundamental component, the location of the plasma level corresponding to the frequency of the burst in the lower band should be consistent with the deprojected location of the leading edge (LE) of the associated CME; (2) the drift speed of the type II bursts derived from such a model should agree closely with the deprojected speed of the LE of the corresponding CMEs. With the above conditions, we find that: (1) the estimated field strengths are unique to each type II burst, and (2) the radial variation of the field strength in the different events indicate a pattern. It is steepest for the case where the heliocentric distance range over which the associated burst is observed is closest to the Sun, and vice versa.
Gauge field theory approach to spin transport in a 2D electron gas
Directory of Open Access Journals (Sweden)
B. Berche
2009-01-01
Full Text Available We discuss the Pauli Hamiltonian including the spin-orbit interaction within an U(1×SU(2 gauge theory interpretation, where the gauge symmetry appears to be broken. This interpretation offers new insight into the problem of spin currents in the condensed matter environment, and can be extended to Rashba and Dresselhaus spin-orbit interactions. We present a few outcomes of the present formulation: i it automatically leads to zero spin conductivity, in contrast to predictions of Gauge symmetric treatments, ii a topological quantization condition leading to voltage quantization follows, and iii spin interferometers can be conceived in which, starting from an arbitrary incoming unpolarized spinor, it is always possible to construct a perfect spin filtering condition.
International Nuclear Information System (INIS)
Nielsen, H.B.; Bennett, D.L.
1987-08-01
Assuming that a lattice gauge theory describes a fundamental attribute of Nature, it should be pointed out that such a theory in the form of a gauge glass is a weaker assumption than a regular lattice model in as much as it is not constrained by the imposition of translational invariance; translational invariance is, however, recovered approximately in the long wavelength or continuum limit. (orig./WL)
Energy Technology Data Exchange (ETDEWEB)
Smiseth, Jo
2005-07-01
The critical properties of three-dimensional U(1)-symmetric lattice gauge theories have been studied. The models apply to various physical systems such as insulating phases of strongly correlated electron systems as well as superconducting and superfluid states of liquid metallic hydrogen under extreme pressures. The thesis contains an introductory part and a collection of research papers of which seven are published works and one is submitted for publication. The outline of this thesis is as follows. In Chapter 2 the theory of phase transitions is discussed with emphasis on continuous phase transitions, critical phenomena and phase transitions in gauge theories. In the next chapter the phases of the abelian Higgs model are presented, and the critical phenomena are discussed. Furthermore, the multicomponent Ginzburg-Landau theory and the applications to liquid metallic hydrogen are presented. Chapter 4 contains an overview of the Monte Carlo integration scheme, including the Metropolis algorithm, error estimates, and re weighting techniques. This chapter is followed by the papers I-VIII. Paper I: Criticality in the (2+1)-Dimensional Compact Higgs Model and Fractionalized Insulators. Paper II: Phase structure of (2+1)-dimensional compact lattice gauge theories and the transition from Mott insulator to fractionalized insulator. Paper III: Compact U(1) gauge theories in 2+1 dimensions and the physics of low dimensional insulating materials. Paper IV: Phase structure of Abelian Chern-Simons gauge theories. Paper V: Critical Properties of the N-Color London Model. Paper VI: Field- and temperature induced topological phase transitions in the three-dimensional N-component London superconductor. Paper VII: Vortex Sublattice Melting in a Two-Component Superconductor. Paper VIII: Observation of a metallic superfluid in a numerical experiment (ml)
Selfduality and topological-like properties of lattice gauge field theories. A proposal
Energy Technology Data Exchange (ETDEWEB)
Cotta-Ramusino, P; Dell' Antonio, G [Freie Univ. Berlin (Germany, F.R.). Inst. fuer Theoretische Physik; Rome Univ. (Italy). Istituto di Matematica)
1979-11-01
We introduce for lattice gauge theories an analogue of the Pontrjagin index and a notion of 'selfduality' and 'antiselfduality'. Selfdual and antiselfdual configurations on the lattice have much of the same properties (with some remarkable differences) as the corresponding configurations on the continuum, to which they converge when the lattice spacing goes to zero.
International Nuclear Information System (INIS)
Membiela, Federico Agustin; Bellini, Mauricio
2010-01-01
Using a semiclassical approach to Gravitoelectromagnetic Inflation (GEMI), we study the origin and evolution of seminal inflaton and electromagnetic fields in the early inflationary universe from a 5D vacuum state. The difference with other previous works is that in this one we use a Lorentz gauge. Our formalism is naturally not conformal invariant on the effective 4D de Sitter metric, which make possible the super adiabatic amplification of magnetic field modes during the early inflationary epoch of the universe on cosmological scales.
Energy Technology Data Exchange (ETDEWEB)
Membiela, Federico Agustin, E-mail: membiela@mdp.edu.a [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350, (7600) Mar del Plata (Argentina); Instituto de Fisica de Mar del Plata (IFIMAR), Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); Bellini, Mauricio, E-mail: mbellini@mdp.edu.a [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350, (7600) Mar del Plata (Argentina); Instituto de Fisica de Mar del Plata (IFIMAR), Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina)
2010-02-22
Using a semiclassical approach to Gravitoelectromagnetic Inflation (GEMI), we study the origin and evolution of seminal inflaton and electromagnetic fields in the early inflationary universe from a 5D vacuum state. The difference with other previous works is that in this one we use a Lorentz gauge. Our formalism is naturally not conformal invariant on the effective 4D de Sitter metric, which make possible the super adiabatic amplification of magnetic field modes during the early inflationary epoch of the universe on cosmological scales.
Membiela, Federico Agustín; Bellini, Mauricio
2010-02-01
Using a semiclassical approach to Gravitoelectromagnetic Inflation (GEMI), we study the origin and evolution of seminal inflaton and electromagnetic fields in the early inflationary universe from a 5D vacuum state. The difference with other previous works is that in this one we use a Lorentz gauge. Our formalism is naturally not conformal invariant on the effective 4D de Sitter metric, which make possible the super adiabatic amplification of magnetic field modes during the early inflationary epoch of the universe on cosmological scales.
International Nuclear Information System (INIS)
Rindani, S.D.
1989-03-01
A gauge-invariant theory of a massive spin-3/2 particle interaction with external electromagnetic and gravitational fields, obtained earlier by Kaluza-Klein reduction of a massless Rarita-Schwinger theory, is quantized using Dirac's procedure. The field anticommutators are found to be positive definite. The theory, which was earlier shown to be free from the classical Velo-Zwanziger problem of noncausal propagation modes, is thus also free from the problem of negative-norm states, a long-standing problem associated with massive spin-3/2 theories with external interaction. (author). 19 refs
International Nuclear Information System (INIS)
Sowerby, B.D.
1982-01-01
Techniques employed in nuclear gauges for the measurement of level, thickness, density and moisture are described. The gauges include both transmission and backscatter gauges and utilize alpha particles, beta particles, neutrons or gamma radiation
Generalized messenger sector for gauge mediation of supersymmetry breaking and the soft spectrum
International Nuclear Information System (INIS)
Marques, Diego
2009-01-01
We consider a generic renormalizable and gauge invariant messenger sector and derive the sparticle mass spectrum using the formalism introduced for General Gauge Mediation. Our results recover many expressions found in the literature in various limits. Constraining the messenger sector with a global symmetry under which the spurion field is charged, we analyze Extraordinary Gauge Mediation beyond the small SUSY breaking limit. Finally, we include D-term contributions and compute their corrections to the soft masses. This leads to a perturbative framework allowing to explore models capable of fully covering the parameter space of General Gauge Mediation to the Supersymmetric Standard Model.
International Nuclear Information System (INIS)
Lassig, C.C.; Joshi, G.C.
1995-01-01
The nonassociativity of the octonion algebra makes necessitates a bimodule representation, in which each element is represented by a left and a right multiplier. This representation can then be used to generate gauge transformations for the purpose of constructing a field theory symmetric under a gauged octonion algebra, the nonassociativity of which appears as a failure of the representation to close, and hence produces new interactions in the gauge field kinetic term of the symmetric Lagrangian. 5 refs., 1 tab
Konstantinou, Georgios; Moulopoulos, Konstantinos
2017-05-01
By perceiving gauge invariance as an analytical tool in order to get insight into the states of the "generalized Landau problem" (a charged quantum particle moving inside a magnetic, and possibly electric field), and motivated by an early article that correctly warns against a naive use of gauge transformation procedures in the usual Landau problem (i.e. with the magnetic field being static and uniform), we first show how to bypass the complications pointed out in that article by solving the problem in full generality through gauge transformation techniques in a more appropriate manner. Our solution provides in simple and closed analytical forms all Landau Level-wavefunctions without the need to specify a particular vector potential. This we do by proper handling of the so-called pseudomomentum ěc {{K}} (or of a quantity that we term pseudo-angular momentum L z ), a method that is crucially different from the old warning argument, but also from standard treatments in textbooks and in research literature (where the usual Landau-wavefunctions are employed - labeled with canonical momenta quantum numbers). Most importantly, we go further by showing that a similar procedure can be followed in the more difficult case of spatially-nonuniform magnetic fields: in such case we define ěc {{K}} and L z as plausible generalizations of the previous ordinary case, namely as appropriate line integrals of the inhomogeneous magnetic field - our method providing closed analytical expressions for all stationary state wavefunctions in an easy manner and in a broad set of geometries and gauges. It can thus be viewed as complementary to the few existing works on inhomogeneous magnetic fields, that have so far mostly focused on determining the energy eigenvalues rather than the corresponding eigenkets (on which they have claimed that, even in the simplest cases, it is not possible to obtain in closed form the associated wavefunctions). The analytical forms derived here for these
Scattering theory of space-time non-commutative abelian gauge field theory
International Nuclear Information System (INIS)
Rim, Chaiho; Yee, Jaehyung
2005-01-01
The unitary S-matrix for space-time non-commutative quantum electrodynamics is constructed using the *-time ordering which is needed in the presence of derivative interactions. Based on this S-matrix, we formulate the perturbation theory and present the Feynman rule. We then apply this perturbation analysis to the Compton scattering process to the lowest order and check the gauge invariance of the scattering amplitude at this order.
International Nuclear Information System (INIS)
Pueyo, Laurent; Hillenbrand, Lynne; Hinkley, Sasha; Dekany, Richard; Roberts, Jenny; Vasisht, Gautam; Roberts, Lewis C. Jr.; Shao, Mike; Burruss, Rick; Cady, Eric; Oppenheimer, Ben R.; Brenner, Douglas; Zimmerman, Neil; Monnier, John D.; Crepp, Justin; Parry, Ian; Beichman, Charles; Soummer, Rémi
2012-01-01
We report low-resolution near-infrared spectroscopic observations of the eruptive star FU Orionis using the Integral Field Spectrograph (IFS) Project 1640 installed at the Palomar Hale telescope. This work focuses on elucidating the nature of the faint source, located 0.''5 south of FU Ori, and identified in 2003 as FU Ori S. We first use our observations in conjunction with published data to demonstrate that the two stars are indeed physically associated and form a true binary pair. We then proceed to extract J- and H-band spectro-photometry using the damped LOCI algorithm, a reduction method tailored for high contrast science with IFS. This is the first communication reporting the high accuracy of this technique, pioneered by the Project 1640 team, on a faint astronomical source. We use our low-resolution near-infrared spectrum in conjunction with 10.2 μm interferometric data to constrain the infrared excess of FU Ori S. We then focus on estimating the bulk physical properties of FU Ori S. Our models lead to estimates of an object heavily reddened, A V = 8-12, with an effective temperature of ∼4000-6500 K. Finally, we put these results in the context of the FU Ori N-S system and argue that our analysis provides evidence that FU Ori S might be the more massive component of this binary system.
Energy Technology Data Exchange (ETDEWEB)
Pueyo, Laurent [Johns Hopkins University, Department of Physics and Astronomy, 366 Bloomberg Center 3400 N. Charles Street, Baltimore, MD 21218 (United States); Hillenbrand, Lynne; Hinkley, Sasha; Dekany, Richard; Roberts, Jenny [Department of Astronomy, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Vasisht, Gautam; Roberts, Lewis C. Jr.; Shao, Mike; Burruss, Rick; Cady, Eric [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Oppenheimer, Ben R.; Brenner, Douglas; Zimmerman, Neil [American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024 (United States); Monnier, John D. [Department of Astronomy, University of Michigan, 941 Dennison Building, 500 Church Street, Ann Arbor, MI 48109-1090 (United States); Crepp, Justin [Department of Physics, 225 Nieuwland Science Hall, University of Notre Dame, Notre Dame, IN 46556 (United States); Parry, Ian [University of Cambridge, Institute of Astronomy, Madingley Road, Cambridge, CB3, OHA (United Kingdom); Beichman, Charles [NASA Exoplanet Science Institute, 770 South Wilson Avenue, Pasadena, CA 91225 (United States); Soummer, Remi [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
2012-09-20
We report low-resolution near-infrared spectroscopic observations of the eruptive star FU Orionis using the Integral Field Spectrograph (IFS) Project 1640 installed at the Palomar Hale telescope. This work focuses on elucidating the nature of the faint source, located 0.''5 south of FU Ori, and identified in 2003 as FU Ori S. We first use our observations in conjunction with published data to demonstrate that the two stars are indeed physically associated and form a true binary pair. We then proceed to extract J- and H-band spectro-photometry using the damped LOCI algorithm, a reduction method tailored for high contrast science with IFS. This is the first communication reporting the high accuracy of this technique, pioneered by the Project 1640 team, on a faint astronomical source. We use our low-resolution near-infrared spectrum in conjunction with 10.2 {mu}m interferometric data to constrain the infrared excess of FU Ori S. We then focus on estimating the bulk physical properties of FU Ori S. Our models lead to estimates of an object heavily reddened, A{sub V} = 8-12, with an effective temperature of {approx}4000-6500 K. Finally, we put these results in the context of the FU Ori N-S system and argue that our analysis provides evidence that FU Ori S might be the more massive component of this binary system.
Particle on a torus knot: Constrained dynamics and semi-classical quantization in a magnetic field
Energy Technology Data Exchange (ETDEWEB)
Das, Praloy, E-mail: praloydasdurgapur@gmail.com; Pramanik, Souvik, E-mail: souvick.in@gmail.com; Ghosh, Subir, E-mail: subirghosh20@gmail.com
2016-11-15
Kinematics and dynamics of a particle moving on a torus knot poses an interesting problem as a constrained system. In the first part of the paper we have derived the modified symplectic structure or Dirac brackets of the above model in Dirac’s Hamiltonian framework, both in toroidal and Cartesian coordinate systems. This algebra has been used to study the dynamics, in particular small fluctuations in motion around a specific torus. The spatial symmetries of the system have also been studied. In the second part of the paper we have considered the quantum theory of a charge moving in a torus knot in the presence of a uniform magnetic field along the axis of the torus in a semiclassical quantization framework. We exploit the Einstein–Brillouin–Keller (EBK) scheme of quantization that is appropriate for multidimensional systems. Embedding of the knot on a specific torus is inherently two dimensional that gives rise to two quantization conditions. This shows that although the system, after imposing the knot condition reduces to a one dimensional system, even then it has manifested non-planar features which shows up again in the study of fractional angular momentum. Finally we compare the results obtained from EBK (multi-dimensional) and Bohr–Sommerfeld (single dimensional) schemes. The energy levels and fractional spin depend on the torus knot parameters that specifies its non-planar features. Interestingly, we show that there can be non-planar corrections to the planar anyon-like fractional spin.
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.
Polewski, Przemyslaw; Yao, Wei; Heurich, Marco; Krzystek, Peter; Stilla, Uwe
2018-06-01
In this study, we present a method for improving the quality of automatic single fallen tree stem segmentation in ALS data by applying a specialized constrained conditional random field (CRF). The entire processing pipeline is composed of two steps. First, short stem segments of equal length are detected and a subset of them is selected for further processing, while in the second step the chosen segments are merged to form entire trees. The first step is accomplished using the specialized CRF defined on the space of segment labelings, capable of finding segment candidates which are easier to merge subsequently. To achieve this, the CRF considers not only the features of every candidate individually, but incorporates pairwise spatial interactions between adjacent segments into the model. In particular, pairwise interactions include a collinearity/angular deviation probability which is learned from training data as well as the ratio of spatial overlap, whereas unary potentials encode a learned probabilistic model of the laser point distribution around each segment. Each of these components enters the CRF energy with its own balance factor. To process previously unseen data, we first calculate the subset of segments for merging on a grid of balance factors by minimizing the CRF energy. Then, we perform the merging and rank the balance configurations according to the quality of their resulting merged trees, obtained from a learned tree appearance model. The final result is derived from the top-ranked configuration. We tested our approach on 5 plots from the Bavarian Forest National Park using reference data acquired in a field inventory. Compared to our previous segment selection method without pairwise interactions, an increase in detection correctness and completeness of up to 7 and 9 percentage points, respectively, was observed.
Quantum and classical gauge symmetries
International Nuclear Information System (INIS)
Fujikawa, Kazuo; Terashima, Hiroaki
2001-01-01
The use of the mass term of the gauge field as a gauge fixing term, which was discussed by Zwanziger, Parrinello and Jona-Lasinio in a large mass limit, is related to the non-linear gauge by Dirac and Nambu. We have recently shown that this use of the mass term as a gauge fixing term is in fact identical to the conventional local Faddeev-Popov formula without taking a large mass limit, if one takes into account the variation of the gauge field along the entire gauge orbit. This suggests that the classical massive vector theory, for example, could be re-interpreted as a gauge invariant theory with a gauge fixing term added in suitably quantized theory. As for massive gauge particles, the Higgs mechanics, where the mass term is gauge invariant, has a more intrinsic meaning. We comment on several implications of this observation. (author)
International Nuclear Information System (INIS)
Krasnikov, N.V.
1987-01-01
Nonlocal gauge theories including gravity are considered. It is shown that the introduction of the additional nonlocal interaction makes γ 5 -anomalous theories meaningful. The introduction of such interaction leads to macrocausal unitary theory, which describes the interaction of massive vector fields with fermion fields. It is shown that nonlocal gauge theories with nonlocal scale Λ nl ≤(1-10) TeV can solve the gauge hierarchy problem. An example of nonlinear grand unified gauge model in which topologically nontrivial finite energy monopole solutions are absent is found
International Nuclear Information System (INIS)
Naik, S.
1990-01-01
We have developed a mean field theory technique to study the confinement-deconfinement phase transition and chiral symmetry restoring phase transition with dynamical fermions and with finite chemical potential and finite temperature. The approximation scheme concerns the saddle point scenario and large space dimension. The static quark-antiquark potentials are identified from the Wilson loop correlation functions in both the fundamental and the adjoint representation of the gauge group with different temperatures. The difference between the responses of the chemical potential to the fermion number with singlet and non-singlet isospin configuration is found. We compare our results with recent Monte Carlo data. (orig.)
Probing CP-violating Higgs and gauge-boson couplings in the Standard Model effective field theory
Energy Technology Data Exchange (ETDEWEB)
Ferreira, Felipe [University of Sussex, Department of Physics and Astronomy, Brighton (United Kingdom); Universidade Federal da Paraiba, Departamento de Fisica, Joao Pessoa, Paraiba (Brazil); Fuks, Benjamin [Sorbonne Universites, Universite Pierre et Marie Curie (Paris 06), UMR 7589, LPTHE, Paris (France); CNRS, UMR 7589, LPTHE, Paris (France); Institut Universitaire de France, Paris (France); Sanz, Veronica [University of Sussex, Department of Physics and Astronomy, Brighton (United Kingdom); Sengupta, Dipan [Universite Grenoble-Alpes, CNRS/IN2P3, Laboratoire de Physique Subatomique et de Cosmologie, Grenoble (France); Michigan State University, Department of Physics and Astronomy, East Lansing (United States)
2017-10-15
We study the phenomenological consequences of several CP-violating structures that could arise in the Standard Model effective field theory framework. Focusing on operators involving electroweak gauge and/or Higgs bosons, we derive constraints originating from Run I LHC data. We then study the capabilities of the present and future LHC runs at higher energies to further probe associated CP-violating phenomena and we demonstrate how differential information can play a key role. We consider both traditional four-lepton probes of CP-violation in the Higgs sector and novel new physics handles based on varied angular and non-angular observables. (orig.)
International Nuclear Information System (INIS)
Scheck, Florian
2010-01-01
Stringent presentation of field theory, mediates the connection from the classicalelectrodynamics up to modern gauge theories. The compact presentation is ideal for the bachelor study. New chapter on general relativity theory. Deepens the learned by numerous application from laser physic, metamaterials and different more. Theoretical physics 3. Classical field theory. On electrodynamics, non-Abelian, and gravitation is the third of five volumes on theoretical physics by professor Scheck. The cycle theoretical physics comprehends: Volume 1: Mechanics. From Newtons law to the deterministic chaos. Volume 2: Nonrelativistic quantum theory. From the hydrogen atom to the many-particle systems. Volume 3: Classical field theory. From the electrodynamics to the gauge theories. Volume 5: From the laws of thermodynamics to the quantum statistics. This textbook mediates modern theoretical physics in string presentation illustrated by many examples. It contains numerous problems with solution hints ore exemplary, complete solutions. The third edition was revised in many single topics, especially the chapter on general relativity theory was supplemented by an extensive analysis of the Schwarzschild solution. [de
Quantum field theory I foundations and Abelian and non-Abelian gauge theories
Manoukian, Edouard B
2016-01-01
This textbook covers a broad spectrum of developments in QFT, emphasizing those aspects that are now well consolidated and for which satisfactory theoretical descriptions have been provided. The book is unique in that it offers a new approach to the subject and explores many topics merely touched upon, if covered at all, in standard reference works. A detailed and largely non-technical introductory chapter traces the development of QFT from its inception in 1926. The elegant functional differential approach put forward by Schwinger, referred to as the quantum dynamical (action) principle, and its underlying theory are used systematically in order to generate the so-called vacuum-to-vacuum transition amplitude of both abelian and non-abelian gauge theories, in addition to Feynman’s well-known functional integral approach, referred to as the path-integral approach. Given the wealth of information also to be found in the abelian case, equal importance is put on both abelian and non-abelian gauge theories. Pa...
Nonperturbative dynamics of hot non-Abelian gauge fields: Beyond the leading log approximation
International Nuclear Information System (INIS)
Arnold, Peter; Yaffe, Laurence G.
2000-01-01
Many aspects of high-temperature gauge theories, such as the electroweak baryon number violation rate, color conductivity, and the hard gluon damping rate, have previously been understood only at leading logarithmic order (that is, neglecting effects suppressed only by an inverse logarithm of the gauge coupling). We discuss how to systematically go beyond leading logarithmic order in the analysis of physical quantities. Specifically, we extend to next-to-leading-log order (NLLO) the simple leading-log effective theory due to Bo''deker that describes non-perturbative color physics in hot non-Abelian plasmas. A suitable scaling analysis is used to show that no new operators enter the effective theory at next-to-leading-log order. However, a NLLO calculation of the color conductivity is required, and we report the resulting value. Our NLLO result for the color conductivity can be trivially combined with previous numerical work by Moore to yield a NLLO result for the hot electroweak baryon number violation rate
International Nuclear Information System (INIS)
Partovi, M.H.
1982-01-01
From a generalization of the covariant derivative, nonlocal gauge theories are developed. These theories enjoy local gauge invariance and associated Ward identities, a corresponding locally conserved current, and a locally conserved energy-momentum tensor, with the Ward identities implying the masslessness of the gauge field as in local theories. Their ultraviolet behavior allows the presence as well as the absence of the Adler-Bell-Jackiw anomaly, the latter in analogy with lattice theories
International Nuclear Information System (INIS)
Greensite, J.; Olejnik, S.
2003-01-01
We study the phase structure of SU(2) gauge theories at zero and high temperature, with and without scalar matter fields, in terms of the symmetric/broken realization of the remnant gauge symmetry which exists after fixing to Coulomb gauge. The symmetric realization is associated with a linearly rising color Coulomb potential (which we compute numerically), and is a necessary but not sufficient condition for confinement.
Haese, B.; Hörning, S.; Chwala, C.; Bárdossy, A.; Schalge, B.; Kunstmann, H.
2017-12-01
For the reconstruction and interpolation of precipitation fields, we present the application of a stochastic approach called Random Mixing. Generated fields are based on a data set consisting of rain gauge observations and path-averaged rain rates estimated using Commercial Microwave Link (CML) derived information. Precipitation fields are received as linear combination of unconditional spatial random fields, where the spatial dependence structure is described by copulas. The weights of the linear combination are optimized such that the observations and the spatial structure of the precipitation observations are reproduced. The innovation of the approach is that this strategy enables the simulation of ensembles of precipitation fields of any size. Each ensemble member is in concordance with the observed path-averaged CML derived rain rates and additionally reflects the observed rainfall variability along the CML paths. The ensemble spread allows additionally an estimation of the uncertainty of the reconstructed precipitation fields. The method is demonstrated both for a synthetic data set and a real-world data set in South Germany. While the synthetic example allows an evaluation against a known reference, the second example demonstrates the applicability for real-world observations. Generated precipitation fields of both examples reproduce the spatial precipitation pattern in good quality. A performance evaluation of Random Mixing compared to Ordinary Kriging demonstrates an improvement of the reconstruction of the observed spatial variability. Random Mixing is concluded to be a beneficial new approach for the provision of precipitation fields and ensembles of them, in particular when different measurement types are combined.
Initial-boundary-value problem of the self-gravitating scalar field in the Bondi-Sachs gauge
International Nuclear Information System (INIS)
Frittelli, Simonetta; Gomez, Roberto
2007-01-01
It is shown that, in the Bondi-Sachs gauge that fixes the speed of incoming light rays to the value 1, the Einstein equations coupled to a scalar field in spherical symmetry are cast into a symmetric-hyperbolic system of equations for the scalar field, lapse and shift as fundamental variables. In this system of equations, the lapse and shift are incoming characteristic fields, and the scalar field has three components: incoming, outgoing and static. A constraint-preserving boundary condition is prescribed by imposing the projection of the Einstein equation normal to the boundary at the outer value of the radial coordinate. The boundary condition specifies one of the two incoming metric fields. The remaining incoming metric field and the incoming scalar field component need to be specified arbitrarily. Numerical simulations of the scattering of the scalar field by a black hole in the nonlinear regime are presented that illustrate interesting facts about black-hole physics and the behavior of the characteristic variables of the problem
Energy Technology Data Exchange (ETDEWEB)
Bossard, G
2007-10-15
This thesis contains 2 parts based on scientific contributions that have led to 2 series of publications. The first one concerns the introduction of vector symmetry in cohomological theories, through a generalization of the so-called Baulieu-Singer equation. Together with the topological BRST (Becchi-Rouet-Stora-Tyutin) operator, this symmetry gives an off-shell closed sub-sector of supersymmetry that permits to determine the action uniquely. The second part proposes a methodology for re-normalizing supersymmetric Yang-Mills theory without assuming a regularization scheme which is both supersymmetry and gauge invariance preserving. The renormalization prescription is derived thanks to the definition of 2 consistent Slavnov-Taylor operators for supersymmetry and gauge invariance, whose construction requires the introduction of the so-called shadow fields. We demonstrate the renormalizability of supersymmetric Yang-Mills theories. We give a fully consistent, regularization scheme independent, proof of the vanishing of the {beta} function and of the anomalous dimensions of the one half BPS operators in maximally supersymmetric Yang-Mills theory. After a short introduction, in chapter two, we give a review of the cohomological Yang-Mills theory in eight dimensions. We then study its dimensional reductions in seven and six dimensions. The last chapter gives quite independent results, about a geometrical interpretation of the shadow fields, an unpublished work about topological gravity in four dimensions, an extension of the shadow formalism to superconformal invariance, and finally the solution of the constraints in a twisted superspace. (author)
Kaehler-Chern-Simons theory and symmetries of anti-self-dual gauge fields
International Nuclear Information System (INIS)
Nair, V.P.; Schiff, J.
1992-01-01
Kaehler-Chern-Simons theory, which was proposed as a generalization of ordinary Chern-Simons theory, is explored in more detail. The theory describes anti-self-dual instantons on a four-dimensional Kaehler manifold. The phase space is the space of gauge potentials, whose symplectic reduction by the constraints of anti-self-duality leads to the moduli space of instantons. We show that infinitesimal Baecklund transformations, previously related to 'hidden symmetries' of instantons, are canonical transformations generated by the anti-self-duality constraints. The quantum wave functions naturally lead to a generalized Wess-Zumino-Witten action, which in turn has associated chiral current algebras. The dimensional reduction of the anti-self-duality equations leading to integrable two-dimensional theories is briefly discussed in this framework. (orig.)
Effects of the quark field on the ghost propagator of lattice Landau gauge QCD
International Nuclear Information System (INIS)
Furui, Sadataka; Nakajima, Hideo
2006-01-01
Infrared features of the ghost propagator of color-diagonal and color antisymmetric ghost propagator of quenched SU(2) and quenched SU(3) are compared with those of unquenched Kogut-Susskind fermion SU(3) lattice Landau gauge. We compare (i) the fluctuation of the ghost propagator (ii) the ghost condensate parameter v of the local composite operator (LCO) approach, and (iii) the Binder cumulant of color antisymmetric ghost propagator between quenched and unquenched configurations. The color-diagonal SU(3) ghost dressing function of unquenched configurations has weaker singularity than the quenched configurations. In both cases fluctuations become large in q c configuration samples is ∼0.002-0.04 GeV 2 while that of the SU(2) parallel tempering samples is consistent with 0. The Binder cumulant defined as U(q)=1-(1/3)( 4 >/( 2 >) 2 ), where φ-vector(q) is the color antisymmetric ghost propagator measured by the sample average of gauge fixed configurations via parallel tempering method, becomes ∼4/9 in all the momentum region. The Binder cumulant of the color antisymmetric ghost propagator of quenched SU(2) can be explained by the 3D Gaussian distribution, but that of the unquenched MILC c deviates slightly from that of the eight-dimensional Gaussian distribution. The stronger singularity and large fluctuation in the quenched configuration could be the cause of the deviation of the Kugo-Ojima confinement parameter c from 1, and the presence of ordering in the ghost propagator of unquenched configurations makes it closer to 1
Topological insulators in cold-atom gases with non-Abelian gauge fields: the role of interactions
Energy Technology Data Exchange (ETDEWEB)
Orth, Peter Philipp [Institut fuer Theorie der Kondensierten Materie, Karlsruher Institut fuer Technologie, 76128 Karlsruhe (Germany); Cocks, Daniel; Buchhold, Michael; Hofstetter, Walter [Institut fuer Theoretische Physik, Goethe Universitaet, 60438 Frankfurt am Main (Germany); Rachel, Stephan [Department of Physics, Yale University, New Haven, Connecticut 06520 (United States); Le Hur, Karyn [Department of Physics, Yale University, New Haven, Connecticut 06520 (United States); Center for Theoretical Physics, Ecole Polytechnique, 91128 Palaiseau Cedex (France)
2012-07-01
With the recent technological advance of creating (non)-Abelian gauge fields for ultracold atoms in optical lattices, it becomes possible to study the interplay of topological phases and interactions in these systems. Specifically, we consider a spinful and time-reversal invariant version of the Hofstadter problem. In addition, we allow for a hopping term which does not preserve S{sub z} spin symmetry and a staggered sublattice potential. Without interactions, the parameters can be tuned such that the system is a topological insulator. Using a combination of analytical techniques and the powerful real-space dynamical mean-field (R-DMFT) method, we discuss the effect of interactions and determine the interacting phase diagram.
International Nuclear Information System (INIS)
Blau, M.; Thompson, G.
1995-01-01
We review localization techniques for functional integrals which have recently been used to perform calculations in and gain insight into the structure of certain topological field theories and low-dimensional gauge theories. These are the functional integral counterparts of the Mathai-Quillen formalism, the Duistermaat-Heckman theorem, and the Weyl integral formula respectively. In each case, we first introduce the necessary mathematical background (Euler classes of vector bundles, equivariant cohomology, topology of Lie groups), and describe the finite dimensional integration formulae. We then discuss some applications to path integrals and give an overview of the relevant literature. The applications we deal with include supersymmetric quantum mechanics, cohomological field theories, phase space path integrals, and two-dimensional Yang-Mills theory. (author). 83 refs
International Nuclear Information System (INIS)
Bartels, J.; Wu, T.T.
1988-01-01
This paper contains the first part of a systematic semiclassical analysis of the weak-coupling limit of lattice gauge theories, using the Hamiltonian formulation. The model consists of an N 3 cubic lattice of pure SU(2) Yang-Mills theory, and in this first part we limit ourselves to the subspace of constant field configurations. We investigate the flow of classical trajectories, with a particular emphasis on the existence and location of caustics. There the ground-state wave function is expected to peak. It is found that regions densely filled with caustics are very close to the origin, i.e., in the domain of weak field configurations. This strongly supports the expectation that caustics are essential for quantities of physical interest
Nonabelian generalized gauge multiplets
International Nuclear Information System (INIS)
Lindstroem, Ulf; Zabzine, Maxim; Rocek, Martin; Ryb, Itai; Unge, Rikard von
2009-01-01
We give the nonabelian extension of the newly discovered N = (2, 2) two-dimensional vector multiplets. These can be used to gauge symmetries of sigma models on generalized Kaehler geometries. Starting from the transformation rule for the nonabelian case we find covariant derivatives and gauge covariant field-strengths and write their actions in N = (2, 2) and N = (1, 1) superspace.
International Nuclear Information System (INIS)
Kikkawa, Keiji; Nakanishi, Noboru; Nariai, Hidekazu
1983-01-01
These proceedings contain the articles presented at the named symposium. They deal with geometrical aspects of gauge theory and gravitation, special problems in gauge theories, quantum field theory in curved space-time, quantum gravity, supersymmetry including supergravity, and grand unification. See hints under the relevant topics. (HSI)
Constrained superfields in supergravity
Energy Technology Data Exchange (ETDEWEB)
Dall’Agata, Gianguido; Farakos, Fotis [Dipartimento di Fisica ed Astronomia “Galileo Galilei”, Università di Padova,Via Marzolo 8, 35131 Padova (Italy); INFN, Sezione di Padova,Via Marzolo 8, 35131 Padova (Italy)
2016-02-16
We analyze constrained superfields in supergravity. We investigate the consistency and solve all known constraints, presenting a new class that may have interesting applications in the construction of inflationary models. We provide the superspace Lagrangians for minimal supergravity models based on them and write the corresponding theories in component form using a simplifying gauge for the goldstino couplings.
On the gauge symmetries of Maxwell-like higher-spin Lagrangians
International Nuclear Information System (INIS)
Francia, Dario; Lyakhovich, Simon L.; Sharapov, Alexey A.
2014-01-01
In their simplest form, metric-like Lagrangians for higher-spin massless fields are usually assumed to display constrained gauge symmetries, unless auxiliary fields are introduced or locality is foregone. Specifically, in its standard incarnation, gauge invariance of Maxwell-like Lagrangians relies on parameters with vanishing divergence. We find an alternative form of the corresponding local symmetry involving unconstrained gauge parameters of mixed-symmetry type, described by rectangular two-row Young diagrams and entering high-derivative gauge transformations. The resulting gauge algebra appears to be reducible and we display the full pattern of gauge-for-gauge parameters, testing its correctness via the corresponding counting of degrees of freedom. The algebraic techniques applied in this work also allow us to elucidate some general properties of linear gauge systems. In particular, we establish the general fact that any linear local field theory always admits unconstrained, local, and finitely reducible parametrization of the gauge symmetry. Incidentally, this shows that massless higher spins admit a local unconstrained formulation with no need for auxiliary fields
Derivation of the gauge link in light cone gauge
International Nuclear Information System (INIS)
Gao Jianhua
2010-01-01
In light cone gauge, a gauge link at light cone infinity is necessary for transverse momentum-dependent parton distribution to restore the gauge invariance in some specific boundary conditions. We derive such transverse gauge link in a more regular and general method. We find the gauge link at light cone infinity naturally arises from the contribution of the pinched poles: one is from the quark propagator and the other is hidden in the gauge vector field in light cone gauge. Actually, in the amplitude level, we have obtained a more general gauge link over the hypersurface at light cone infinity which is beyond the transverse direction. The difference of such gauge link between semi-inclusive deep inelastic scattering and Drell-Yan processes can also be obtained directly and clearly in our derivation.
q q ¯ Pair production in non-Abelian gauge fields
Indian Academy of Sciences (India)
Non-Abelian interactions in the colour field are time-dependent and hence should oscillate with a characteristic frequency 0 , which depends on the amplitude of the field strength. Using the WKB approximation in complex time, we calculated the pair production probability. When the strength of the field is comparable to the ...
International Nuclear Information System (INIS)
Kummer, W.; Mistelberger, H.; Schaller, P.; Schweda, M.
1989-01-01
Supersymmetric gauge theories can be suitably quantized in non-supersymmetric 'superaxial' gauges without abolishing the basic advantages of the superfield technique. In this review the state of the art is presented. It includes the proof of renormalization and the proof of gauge independence and supersymmetry of observable physical quantities. (author)
Ambiguities on electric and magnetic fields for an extended gauge model
International Nuclear Information System (INIS)
Colatto, L.P.; Doria, R.M.
1990-01-01
Generalized electric and magnetic fields in a system containing N-potential fields in the same U (1) - group are obtained. Bianchi identities, equations of motions, conserved charges and Lorentz forces are developed in association to each of these fields. Such facts confirm that the same parameter α (x) is able to organize the presence of distinct fields. The physics generated from the minimal action principle is independent of the initial definition for the electric (magnetic) field. Nevertheless, such a choice reveals differences in the Bianchi identity context. (author)
Self-dual gauge field, its quantum fluctuations, and interacting fermions
International Nuclear Information System (INIS)
Flory, C.A.
1983-01-01
The quantum fluctuations about a self-dual background field in SU(2) are computed. The background field consists of parallel and equal uniform chromomagnetic and chromoelectric fields. Determination of the gluon fluctuations about this field yields zero modes, which are naturally regularized by the introduction of massless fermions. This regularization makes the integrals over all fluctuations convergent, and allows a simple computation of the vacuum energy which is shown to be lower than the energy of the configuration of zero field strength. The regularization of the zero modes also facilitates the introduction of heavy test charges which can interact with the classical background field and also exchange virtual quanta. The formalism for introducing these heavy test charges could be a good starting point for investigating the relevant physics of the self-dual background field beyond the classical level
Markov, Yu. A.; Shishmarev, A. A.
2010-11-01
Based on the most general principles of materiality, gauge, and re-parameterized invariance, the problem of constructing an action describing the dynamics of a classical color-charged particle moving in external non-Abelian gauge and fermion fields is considered. The case of a linear Lagrangian dependence on the external fermion fields is discussed. Within the framework of the description of the color degree of freedom of the particle with half-integer spin by the Grassmann color charges, a new concept of the Grassmann color source of the particle being a fermion analog of the conventional color current is introduced.
Chirality conservation in the lattice gauge theory
International Nuclear Information System (INIS)
Peskin, M.E.
1978-01-01
The derivation of conservation laws corresponding to chiral invariance in quantum field theories of interacting quarks and gluons are studied. In particular there is interest in observing how these conservation laws are constrained by the requirement that the field theory be locally gauge invariant. To examine this question, a manifestly gauge-invariant definition of local operators in a quantum field theory is introduced, a definition which relies in an essential way on the use of the formulation of gauge fields on a lattice due to Wilson and Polyakov to regulate ultraviolet divergences. The conceptual basis of the formalism is set out and applied to a long-standing puzzle in the phenomenology of quark-gluon theories: the fact that elementary particle interactions reflect the conservation of isospin-carrying chiral currents but not of the isospin-singlet chiral current. It is well known that the equation for the isospin-singlet current contains an extra term, the operator F/sub mu neu/F/sup mu neu/, not present in the other chirality conservation laws; however, this term conventionally has the form of a total divergence and so still allows the definition of a conserved chiral current. It is found that, when the effects of maintaining gauge invariance are properly taken into account, the structure of this operator is altered by renormalization effects, so that it provides an explicit breaking of the unwanted chiral invariance. The relation between this argument, based on renormaliztion, is traced to a set of more heuristic arguments based on gauge field topology given by 't Hooft; it is shown that the discussion provides a validation, through short-distance analysis, of the picture 'Hooft has proposed. The formal derivation of conservation laws for chiral currents are set out in detail
International Nuclear Information System (INIS)
Tominaga, Hiroshi
1980-01-01
A survey was made by Japan Atomic Industrial Forum, Inc., in August, 1979, on the uses of isotope-equipped measuring instruments in private industrial enterprises by sending questionnaires to 1372 enterprises using sealed radiation sources. The results are described. i.e. usage of isotope-equipped measuring instruments, the economic effects, and problems for the future, and also the general situation in this field. Such instruments used are gas chromatography apparatus, thickness, level and moisture gauges, sulfur analyzer, etc. Except the gas chromatography, the rest are mostly incorporated in automatic control systems. As the economic effects, there are the rises in productivity, quality and yield and the savings in materials, energy and manpower. While they are used to great advantage, there are still problems occasionally in measuring accuracy and others. (J.P.N.)
BPS Center Vortices in Nonrelativistic SU(N) Gauge Models with Adjoint Higgs Fields
International Nuclear Information System (INIS)
Oxman, L. E.
2015-01-01
We propose a class of SU(N) Yang-Mills models, with adjoint Higgs fields, that accept BPS center vortex equations. The lack of a local magnetic flux that could serve as an energy bound is circumvented by including a new term in the energy functional. This term tends to align, in the Lie algebra, the magnetic field and one of the adjoint Higgs fields. Finally, a reduced set of equations for the center vortex profile functions is obtained (for N=2,3). In particular, Z(3) BPS vortices come in three colours and three anticolours, obtained from an ansatz based on the defining representation and its conjugate.
Energy Technology Data Exchange (ETDEWEB)
Veres, P.; Dermer, C. D.; Dhuga, K. S. [Department of Physics, George Washington University, Washington, DC 20052 (United States)
2017-09-20
The magnetic field in intergalactic space gives important information about magnetogenesis in the early universe. The properties of this field can be probed by searching for radiation of secondary e {sup +} e {sup −} pairs created by TeV photons that produce GeV range radiation by Compton-scattering cosmic microwave background photons. The arrival times of the GeV “echo” photons depend strongly on the magnetic field strength and coherence length. A Monte Carlo code that accurately treats pair creation is developed to simulate the spectrum and time-dependence of the echo radiation. The extrapolation of the spectrum of powerful gamma-ray bursts (GRBs) like GRB 130427A to TeV energies is used to demonstrate how the intergalactic magnetic field can be constrained if it falls in the 10{sup −21}–10{sup −17} G range for a 1 Mpc coherence length.
Temperature-Dependent Coercive Field Measured by a Quantum Dot Strain Gauge.
Chen, Yan; Zhang, Yang; Keil, Robert; Zopf, Michael; Ding, Fei; Schmidt, Oliver G
2017-12-13
Coercive fields of piezoelectric materials can be strongly influenced by environmental temperature. We investigate this influence using a heterostructure consisting of a single crystal piezoelectric film and a quantum dots containing membrane. Applying electric field leads to a physical deformation of the piezoelectric film, thereby inducing strain in the quantum dots and thus modifying their optical properties. The wavelength of the quantum dot emission shows butterfly-like loops, from which the coercive fields are directly derived. The results suggest that coercive fields at cryogenic temperatures are strongly increased, yielding values several tens of times larger than those at room temperature. We adapt a theoretical model to fit the measured data with very high agreement. Our work provides an efficient framework for predicting the properties of ferroelectric materials and advocating their practical applications, especially at low temperatures.
Chiral Anomaly from Strain-Induced Gauge Fields in Dirac and Weyl Semimetals
Directory of Open Access Journals (Sweden)
D. I. Pikulin
2016-10-01
Full Text Available Dirac and Weyl semimetals form an ideal platform for testing ideas developed in high-energy physics to describe massless relativistic particles. One such quintessentially field-theoretic idea of the chiral anomaly already resulted in the prediction and subsequent observation of the pronounced negative magnetoresistance in these novel materials for parallel electric and magnetic fields. Here, we predict that the chiral anomaly occurs—and has experimentally observable consequences—when real electromagnetic fields E and B are replaced by strain-induced pseudo-electromagnetic fields e and b. For example, a uniform pseudomagnetic field b is generated when a Weyl semimetal nanowire is put under torsion. In accordance with the chiral anomaly equation, we predict a negative contribution to the wire resistance proportional to the square of the torsion strength. Remarkably, left- and right-moving chiral modes are then spatially segregated to the bulk and surface of the wire forming a “topological coaxial cable.” This produces hydrodynamic flow with potentially very long relaxation time. Another effect we predict is the ultrasonic attenuation and electromagnetic emission due to a time-periodic mechanical deformation causing pseudoelectric field e. These novel manifestations of the chiral anomaly are most striking in the semimetals with a single pair of Weyl nodes but also occur in Dirac semimetals such as Cd_{3}As_{2} and Na_{3}Bi and Weyl semimetals with unbroken time-reversal symmetry.
Chiral Anomaly from Strain-Induced Gauge Fields in Dirac and Weyl Semimetals
Pikulin, D. I.; Chen, Anffany; Franz, M.
2016-10-01
Dirac and Weyl semimetals form an ideal platform for testing ideas developed in high-energy physics to describe massless relativistic particles. One such quintessentially field-theoretic idea of the chiral anomaly already resulted in the prediction and subsequent observation of the pronounced negative magnetoresistance in these novel materials for parallel electric and magnetic fields. Here, we predict that the chiral anomaly occurs—and has experimentally observable consequences—when real electromagnetic fields E and B are replaced by strain-induced pseudo-electromagnetic fields e and b . For example, a uniform pseudomagnetic field b is generated when a Weyl semimetal nanowire is put under torsion. In accordance with the chiral anomaly equation, we predict a negative contribution to the wire resistance proportional to the square of the torsion strength. Remarkably, left- and right-moving chiral modes are then spatially segregated to the bulk and surface of the wire forming a "topological coaxial cable." This produces hydrodynamic flow with potentially very long relaxation time. Another effect we predict is the ultrasonic attenuation and electromagnetic emission due to a time-periodic mechanical deformation causing pseudoelectric field e . These novel manifestations of the chiral anomaly are most striking in the semimetals with a single pair of Weyl nodes but also occur in Dirac semimetals such as Cd3 As2 and Na3Bi and Weyl semimetals with unbroken time-reversal symmetry.
Energy Technology Data Exchange (ETDEWEB)
Jurčo, Branislav, E-mail: jurco@karlin.mff.cuni.cz [Charles University in Prague, Faculty of Mathematics and Physics, Mathematical Institute, Prague 186 75 (Czech Republic); Schupp, Peter, E-mail: p.schupp@jacobs-university.de [Jacobs University Bremen, 28759 Bremen (Germany); Vysoký, Jan, E-mail: vysokjan@fjfi.cvut.cz [Jacobs University Bremen, 28759 Bremen (Germany); Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering, Prague 115 19 (Czech Republic)
2014-06-02
We generalize noncommutative gauge theory using Nambu–Poisson structures to obtain a new type of gauge theory with higher brackets and gauge fields. The approach is based on covariant coordinates and higher versions of the Seiberg–Witten map. We construct a covariant Nambu–Poisson gauge theory action, give its first order expansion in the Nambu–Poisson tensor and relate it to a Nambu–Poisson matrix model.
International Nuclear Information System (INIS)
Jurčo, Branislav; Schupp, Peter; Vysoký, Jan
2014-01-01
We generalize noncommutative gauge theory using Nambu–Poisson structures to obtain a new type of gauge theory with higher brackets and gauge fields. The approach is based on covariant coordinates and higher versions of the Seiberg–Witten map. We construct a covariant Nambu–Poisson gauge theory action, give its first order expansion in the Nambu–Poisson tensor and relate it to a Nambu–Poisson matrix model.
Killi, Matthew; Trotzky, Stefan; Paramekanti, Arun
2012-12-01
Bosons and fermions, in the presence of frustration or background gauge fields, can form many-body ground states that support equilibrium charge or spin currents. Motivated by the experimental creation of frustration or synthetic gauge fields in ultracold atomic systems, we propose a general scheme by which making a sudden anisotropic quench of the atom tunneling across the lattice and tracking the ensuing density modulations provides a powerful and gauge-invariant route to probing diverse equilibrium current patterns. Using illustrative examples of trapped superfluid Bose and normal Fermi systems in the presence of artificial magnetic fluxes on square lattices, and frustrated bosons in a triangular lattice, we show that this scheme to probe equilibrium bulk current order works independent of particle statistics. We also show that such quenches can detect chiral edge modes in gapped topological states, such as quantum Hall or quantum spin Hall insulators.
Energy Technology Data Exchange (ETDEWEB)
Kottek, M.; Rubel, F. [Univ. of Veterinary Medicine, Vienna (Austria). Biometeorology Group
2007-10-15
Global daily precipitation analyses are mainly based on satellite estimates, often calibrated with monthly ground analyses or merged with model predictions. We argue here that an essential improvement of their accuracy is only possible by incorporation of daily ground measurements. In this work we apply geostatistical methods to compile a global precipitation product based on daily rain gauge measurements. The raw ground measurements, disseminated via Global Telecommunication System (GTS), are corrected for their systematic measurement errors and interpolated onto a global 1 degree grid. For interpolation ordinary block kriging is applied, with precalculated spatial auto-correlation functions (ACFs). This technique allows to incorporate additional climate information. First, monthly ACFs are calculated from the daily data; second, they are regionalised according to the five main climatic zones of the Koeppen-Geiger climate classification. The interpolation error, a by-product of kriging, is used to flag grid points as missing if the error is above a predefined threshold. But for many applications missing values constitute a problem. Due to a combination of the ground analyses with the daily multi-satellite product of the Global Precipitation Climatology Project (GPCP-1DD) not only these missing values are replaced but also the spatial structure of the satellite estimates is considered. As merging method bivariate ordinary co-kriging is applied. The ACFs necessary for the gauge and the satellite fields as well as the corresponding spatial cross-correlation functions (CCFs) are again precalculated for each of the five main climatic zones and for each individual month. As a result two new global daily data sets for the period 1996 up to today will be available on the Internet (www.gmes-geoland.info): A precipitation product over land, analysed from ground measurements; and a global precipitation product merged from this and the GPCP-1DD multi-satellite product. (orig.)
The interaction of Dirac particles with non-abelian gauge fields and gravity - bound states
Energy Technology Data Exchange (ETDEWEB)
Finster, Felix E-mail: felix.finster@mis.mpg.de; Smoller, Joel E-mail: smoller@umich.edu; Yau, S.-T. E-mail: yau@math.harvard.edu
2000-09-18
We consider a spherically symmetric, static system of a Dirac particle interacting with classical gravity and an SU(2) Yang-Mills field. The corresponding Einstein-Dirac-Yang-Mills equations are derived. Using numerical methods, we find different types of soliton-like solutions of these equations and discuss their properties. Some of these solutions are stable even for arbitrarily weak gravitational coupling.
The interaction of Dirac particles with non-abelian gauge fields and gravity - bound states
Finster, Felix; Smoller, Joel; Yau, Shing-Tung
2000-09-01
We consider a spherically symmetric, static system of a Dirac particle interacting with classical gravity and an SU(2) Yang-Mills field. The corresponding Einstein-Dirac-Yang-Mills equations are derived. Using numerical methods, we find different types of soliton-like solutions of these equations and discuss their properties. Some of these solutions are stable even for arbitrarily weak gravitational coupling.
The interaction of Dirac particles with non-abelian gauge fields and gravity - bound states
International Nuclear Information System (INIS)
Finster, Felix; Smoller, Joel; Yau, S.-T.
2000-01-01
We consider a spherically symmetric, static system of a Dirac particle interacting with classical gravity and an SU(2) Yang-Mills field. The corresponding Einstein-Dirac-Yang-Mills equations are derived. Using numerical methods, we find different types of soliton-like solutions of these equations and discuss their properties. Some of these solutions are stable even for arbitrarily weak gravitational coupling
Constraining Basin Depth and Fault Displacement in the Malombe Basin Using Potential Field Methods
Beresh, S. C. M.; Elifritz, E. A.; Méndez, K.; Johnson, S.; Mynatt, W. G.; Mayle, M.; Atekwana, E. A.; Laó-Dávila, D. A.; Chindandali, P. R. N.; Chisenga, C.; Gondwe, S.; Mkumbwa, M.; Kalaguluka, D.; Kalindekafe, L.; Salima, J.
2017-12-01
The Malombe Basin is part of the Malawi Rift which forms the southern part of the Western Branch of the East African Rift System. At its southern end, the Malawi Rift bifurcates into the Bilila-Mtakataka and Chirobwe-Ntcheu fault systems and the Lake Malombe Rift Basin around the Shire Horst, a competent block under the Nankumba Peninsula. The Malombe Basin is approximately 70km from north to south and 35km at its widest point from east to west, bounded by reversing-polarity border faults. We aim to constrain the depth of the basin to better understand displacement of each border fault. Our work utilizes two east-west gravity profiles across the basin coupled with Source Parameter Imaging (SPI) derived from a high-resolution aeromagnetic survey. The first gravity profile was done across the northern portion of the basin and the second across the southern portion. Gravity and magnetic data will be used to constrain basement depths and the thickness of the sedimentary cover. Additionally, Shuttle Radar Topography Mission (SRTM) data is used to understand the topographic expression of the fault scarps. Estimates for minimum displacement of the border faults on either side of the basin were made by adding the elevation of the scarps to the deepest SPI basement estimates at the basin borders. Our preliminary results using SPI and SRTM data show a minimum displacement of approximately 1.3km for the western border fault; the minimum displacement for the eastern border fault is 740m. However, SPI merely shows the depth to the first significantly magnetic layer in the subsurface, which may or may not be the actual basement layer. Gravimetric readings are based on subsurface density and thus circumvent issues arising from magnetic layers located above the basement; therefore expected results for our work will be to constrain more accurate basin depth by integrating the gravity profiles. Through more accurate basement depth estimates we also gain more accurate displacement
Constraining non-minimally coupled tachyon fields by the Noether symmetry
International Nuclear Information System (INIS)
De Souza, Rudinei C; Kremer, Gilberto M
2009-01-01
A model for a homogeneous and isotropic Universe whose gravitational sources are a pressureless matter field and a tachyon field non-minimally coupled to the gravitational field is analyzed. The Noether symmetry is used to find expressions for the potential density and for the coupling function, and it is shown that both must be exponential functions of the tachyon field. Two cosmological solutions are investigated: (i) for the early Universe whose only source of gravitational field is a non-minimally coupled tachyon field which behaves as an inflaton and leads to an exponential accelerated expansion and (ii) for the late Universe whose gravitational sources are a pressureless matter field and a non-minimally coupled tachyon field which plays the role of dark energy and is responsible for the decelerated-accelerated transition period.
How can we probe the atom mass currents induced by synthetic gauge fields?
Paramekanti, Arun; Killi, Matthew; Trotzky, Stefan
2013-05-01
Ultracold atomic fermions and bosons in an optical lattice can have quantum ground states which support equilibrium currents in the presence of synthetic magnetic fields or spin orbit coupling. As a tool to uncover these mass currents, we propose using an anisotropic quantum quench of the optical lattice which dynamically converts the current patterns into measurable density patterns. Using analytical calculations and numerical simulations, we show that this scheme can probe diverse equilibrium bulk current patterns in Bose superfluids and Fermi fluids induced by synthetic magnetic fields, as well as detect the chiral edge currents in topological states of atomic matter such as quantum Hall and quantum spin Hall insulators. This work is supported by NSERC of Canada and the Canadian Institute for Advanced Research.
Single field inflation in supergravity with a U(1) gauge symmetry
Energy Technology Data Exchange (ETDEWEB)
Heurtier, L. [Centre de Physique Théorique, École Polytechnique, CNRS, 91128 Palaiseau (France); Khalil, S.; Moursy, A., E-mail: lucien.heurtier@polytechnique.edu, E-mail: skhalil@zewailcity.edu.eg, E-mail: amoursy@zewailcity.edu.eg [Center for Fundamental Physics, Zewail City of Science and Technology, 6 October City, Cairo (Egypt)
2015-10-01
A single field inflation based on a supergravity model with a shift symmetry and U(1) extension of the MSSM is analyzed. We show that one of the real components of the two U(1) charged scalar fields plays the role of inflaton with an effective scalar potential similar to the ''new chaotic inflation'' scenario. Both non-anomalous and anomalous (with Fayet-Iliopoulos term) U(1) are studied. We show that the non-anomalous U(1) scenario is consistent with data of the cosmic microwave background and recent astrophysical measurements. A possible kinetic mixing between U(1) and U(1){sub B−L} is considered in order to allow for natural decay channels of the inflaton, leading to a reheating epoch. Upper limits on the reheating temperature thus turn out to favour an intermediate (∼ O(10{sup 13}) GeV) scale B−L symmetry breaking.
Single field inflation in supergravity with a U(1) gauge symmetry
Energy Technology Data Exchange (ETDEWEB)
Heurtier, L. [Centre de Physique Théorique, École Polytechnique, CNRS,91128 Palaiseau (France); Khalil, S. [Center for Fundamental Physics, Zewail City of Science and Technology,6 October City, Cairo (Egypt); Department of Mathematics, Faculty of Science, Ain Shams University,Cairo, 11566 (Egypt); Moursy, A. [Center for Fundamental Physics, Zewail City of Science and Technology,6 October City, Cairo (Egypt)
2015-10-19
A single field inflation based on a supergravity model with a shift symmetry and U(1) extension of the MSSM is analyzed. We show that one of the real components of the two U(1) charged scalar fields plays the role of inflaton with an effective scalar potential similar to the “new chaotic inflation” scenario. Both non-anomalous and anomalous (with Fayet-Iliopoulos term) U(1) are studied. We show that the non-anomalous U(1) scenario is consistent with data of the cosmic microwave background and recent astrophysical measurements. A possible kinetic mixing between U(1) and U(1){sub B−L} is considered in order to allow for natural decay channels of the inflaton, leading to a reheating epoch. Upper limits on the reheating temperature thus turn out to favour an intermediate (∼O(10{sup 13}) GeV) scale B−L symmetry breaking.
Connecting solutions in open string field theory with singular gauge transformations
Czech Academy of Sciences Publication Activity Database
Erler, Theodore; Maccaferri, C.
2012-01-01
Roč. 2012, č. 4 (2012), 1-40 ISSN 1126-6708 Grant - others:EUROHORC and ESF(XE) EYI/07/E010 Institutional research plan: CEZ:AV0Z10100502 Keywords : tachyon condensation * string field theory Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 5.618, year: 2012 http://link.springer.com/article/10.1007%2FJHEP04%282012%29107
Weak principle of equivalence and gauge theory of tetrad aravitational field
International Nuclear Information System (INIS)
Tunyak, V.N.
1978-01-01
It is shown that, unlike the tetrade formulation of the general relativity theory derived from the requirement on the Poincare group localization, the tetrade gravitation theory corresponding to the Trader formulation of the weak equivalence principle, where the nongravitational-matter Lagrangian is the direct covariant generalization of the partial relativistic expression on the Riemann space-time is incompatible with the known method for deriving the calibration theory of the tetrade gravitation field
Role of Lie algebra for confinement in non-abelian gauge field scheme
International Nuclear Information System (INIS)
Fukushima, K.; Sato, H.
2014-01-01
This article reports an explicit function form for confining classical Yang-Mills vector potentials and quantum fluctuations around the classical field. The classical vector potential, which is composed of a confining localized function and an unlocalized function, satisfies the classical Yang-Mills equation. The confining localized function contributes to the Wilson loop, while the unlocalized function makes no contribution to this loop. The confining linear potential between a heavy fermion and antifermion is due to (1) the Lie algebra and (2) the form of the confining localized function which has opposite signs at the positions of the particle and antiparticle along the Wilson loop in the time direction. Some classical confining parts of vector potentials also change sign on inversion of the coordinates of the axis perpendicular to the axis joining the two particles. The localized parts of the vector potentials are squeezed around the axis connecting the two particles, and the string tension of the confining linear potential is derived. Quantum fluctuations are formulated using a field expression in terms of local basis functions in real spacetime. The quantum path integral gives the Coulomb potential between the two particles in addition to the linear potential due to the classical fields
Dilatonic dyon-like black hole solutions in the model with two Abelian gauge fields
Energy Technology Data Exchange (ETDEWEB)
Abishev, M.E. [Institute of Experimental and Theoretical Physics, Al-Farabi Kazakh National University, Almaty (Kazakhstan); Institute of Gravitation and Cosmology, RUDN University, Moscow (Russian Federation); Boshkayev, K.A. [Institute of Experimental and Theoretical Physics, Al-Farabi Kazakh National University, Almaty (Kazakhstan); Ivashchuk, V.D. [Center for Gravitation and Fundamental Metrology, VNIIMS, Moscow (Russian Federation); Institute of Gravitation and Cosmology, RUDN University, Moscow (Russian Federation)
2017-03-15
Dilatonic black hole dyon-like solutions in the gravitational 4d model with a scalar field, two 2-forms, two dilatonic coupling constants λ{sub i} ≠ 0, i = 1,2, obeying λ{sub 1} ≠ -λ{sub 2} and the sign parameter ε = ±1 for scalar field kinetic term are considered. Here ε = -1 corresponds to a ghost scalar field. These solutions are defined up to solutions of two master equations for two moduli functions, when λ{sup 2}{sub i} ≠ 1/2 for ε = -1. Some physical parameters of the solutions are obtained: gravitational mass, scalar charge, Hawking temperature, black hole area entropy and parametrized post-Newtonian (PPN) parameters β and γ. The PPN parameters do not depend on the couplings λ{sub i} and ε. A set of bounds on the gravitational mass and scalar charge are found by using a certain conjecture on the parameters of solutions, when 1 + 2λ{sub i}{sup 2} ε > 0, i = 1,2. (orig.)
International Nuclear Information System (INIS)
Brito, P E de; Nazareno, H N
2007-01-01
In the present work we treat the problem of a particle in a uniform magnetic field along the symmetric gauge, so chosen since the wavefunctions present the required cylindrical symmetry. It is our understanding that by means of this work we can make a contribution to the teaching of the present subject, as well as encourage students to use computer algebra systems in solving problems of quantum mechanics. We obtained the degeneracy of the spectrum of eigenvalues in a very clear way. Through the use of a computer algebra system we show graphs of the probability density associated with different eigenvalues as well as compare such functions for some degenerate states, which helps us to visualize the physics of the problem. We also present a semiclassical model which gives a physical insight regarding the paradoxical fact that eigenfunctions associated with opposite angular momenta and different energy eigenvalues have the same probability density. Finally, by solving the time-dependent Schroedinger equation we obtain the time evolution of a wave packet that at time zero was considered to be localized in a definite region of the lattice. The centroid of such a packet performs an orbit similar to that obtained in the classical treatment of a particle in a magnetic field
Open superstring field theory I: gauge fixing, ghost structure, and propagator
Czech Academy of Sciences Publication Activity Database
Kroyter, M.; Okawa, Y.; Schnabl, Martin; Torii, S.; Zwiebach, B.
2012-01-01
Roč. 2012, č. 3 (2012), 1-34 ISSN 1126-6708 R&D Projects: GA MŠk(CZ) LH11106 Grant - others:EUROHORC and ESF(XE) EYI/07/E010 Institutional research plan: CEZ:AV0Z10100502 Keywords : superstrings and heterotic strings * string field theory Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 5.618, year: 2012 http://link.springer.com/article/10.1007%2FJHEP03%282012%29030
Superfield generating equation of field-antifield formalism as a hyper-gauge theory
Energy Technology Data Exchange (ETDEWEB)
Batalin, Igor A. [P.N. Lebedev Physics Institute, Moscow (Russian Federation); Tomsk State Pedagogical University, Tomsk (Russian Federation); Lavrov, Peter M. [Tomsk State Pedagogical University, Tomsk (Russian Federation); National Research Tomsk State University, Tomsk (Russian Federation)
2017-02-15
Within a superfield approach, we formulate a simple quantum generating equation of the field-antifield formalism. Then we derive the Schroedinger equation with the Hamiltonian whose Δ-exact part serves as a generator to the quantum master transformations. We show that these generators do satisfy a nice composition law in terms of the quantum antibrackets. We also present an Sp(2) symmetric extension to the main construction, with specific features caused by the principal fact that all basic equations become Sp(2) vector-valued ones. (orig.)
International Nuclear Information System (INIS)
Linauskas, S.H.
1988-08-01
Field studies to measure actual radiation exposures of operators of commercial moisture-density gauges were undertaken in several regions of Canada. Newly developed bubble detector dosimeter technology and conventional dosimetry such as thermoluminescent dosimeters (TLDs), integrating electronic dosimeters (DRDs), and CR-39 neutron track-etch detectors were used to estimate the doses received by 23 moisture-density gauge operators and maintenance staff. These radiation dose estimates were supported by mapping radiation fields and accounting for the time an operator was near a gauge. Major findings indicate that gauge maintenance and servicing workers were more likely than gauge operators to receive exposures above the level of 5 mSv, and that neutron doses were roughly the same as gamma doses. Gauge operators receive approximately 75% of their dose when transporting and carrying the gauge. Dose to their hands is similar to the dose to their trunks, but the dose to their feet area is 6 to 30 times higher. Gamma radiation is the primary source of radiation contributing to operator dose
Cavity-induced artificial gauge field in a Bose-Hubbard ladder
Halati, Catalin-Mihai; Sheikhan, Ameneh; Kollath, Corinna
2017-12-01
We consider theoretically ultracold interacting bosonic atoms confined to quasi-one-dimensional ladder structures formed by optical lattices and coupled to the field of an optical cavity. The atoms can collect a spatial phase imprint during a cavity-assisted tunneling along a rung via Raman transitions employing a cavity mode and a transverse running wave pump beam. By adiabatic elimination of the cavity field we obtain an effective Hamiltonian for the bosonic atoms, with a self-consistency condition. Using the numerical density-matrix renormalization-group method, we obtain a rich steady-state diagram of self-organized steady states. Transitions between superfluid to Mott-insulating states occur, on top of which we can have Meissner, vortex liquid, and vortex lattice phases. Also a state that explicitly breaks the symmetry between the two legs of the ladder, namely, the biased-ladder phase, is dynamically stabilized. We investigate the influence that a trapping potential has on the stability of the self-organized phases.
Path integral quantization in the temporal gauge
International Nuclear Information System (INIS)
Scholz, B.; Steiner, F.
1983-06-01
The quantization of non-Abelian gauge theories in the temporal gauge is studied within Feynman's path integral approach. The standard asymptotic boundary conditions are only imposed on the transverse gauge fields. The fictituous longitudinal gauge quanta are eliminated asymptotically by modified boundary conditions. This abolishes the residual time-independent gauge transformations and leads to a unique fixing of the temporal gauge. The resulting path integral for the generating functional respects automatically Gauss's law. The correct gauge field propagator is derived. It does not suffer from gauge singularities at n x k = 0 present in the usual treatment of axial gauges. The standard principal value prescription does not work. As a check, the Wilson loop in temporal gauge is calculated with the new propagator. To second order (and to all orders in the Abelian case) the result agrees with the one obtained in the Feynman and Coulomb gauge. (orig.)
International Nuclear Information System (INIS)
Cabibbo, N.
1983-01-01
This chapter attempts to present some of the fundamental geometrical ideas at the basis of gauge theories. Describes Dirac Monopoles and discusses those ideas that are not usually found in more ''utilitarian'' presentations which concentrate on QCD or on the Glashow-Salam-Weinberg model. This topic was chosen because of the announcement of the possible detection of a Dirac monopole. The existence of monopoles depends on topological features of gauge theories (i.e., on global properties of field configurations which are unique to gauge theories). Discusses global symmetry-local symmetry; the connection; path dependence and the gauge fields; topology and monopoles; the case of SU(3) x U(1); and the 't Hooft-Polyakov monopole
International Nuclear Information System (INIS)
Nielsen, H.B.; Brene, N.
1984-12-01
The fundamental laws of nature may be truely random, or they may be so complicated that a random description is adequate. With this philosophy we examine various ways in which a lattice gauge theory (at the Planck scale) can be generalized. Without here giving up a regular lattice structure (which we really ought to do) we consider two generalizations. Making the action (quenched) random has the effect that the gauge group tends to break down and some gauge bosons become massive, unless the gauge group has special properties: no noncentral corners in the geometry of conjugacy classes and furthermore a connected center. Making the concept of gauge transformation more general has a symmetry breaking effect for groups with outer automorphisms. A study of SU 5 -breaking in the context of the first breakdown mechanism (D. Bennett, E. Buturovic and H. B. Nielsen) is shortly reviewed. (orig.)
Gauge fixing conditions for the SU(3) gauge theory
International Nuclear Information System (INIS)
Ragiadakos, Ch.; Viswanathan, K.S.
1979-01-01
SU(3) gauge theory is quantized in the temporal gauge A 0 =0. Gauge fixing conditions are imposed completely on the electric field components, conjugate to the vector potential Ssub(i) that belongs to the subalgebra SO(3) of SU(3). The generating functional in terms of the independent variables is derived. It is ghost-free and may be regarded as a theory of (non-relativistic) spin-0, 1, 2, and 3 fields. (Auth.)
Gauge-invariant master field in U(∞) LGT: A pathway from the strong to weak coupling phases
International Nuclear Information System (INIS)
Kazakov, V.A.; Migdal, A.A.
1987-01-01
We propose and test a new computational method for SU(∞) lattice gauge and spin theories. It is based on calculation of the effective action depending only on N (rather than N 2 ) gauge invariant degrees of freedom, by means of some modification of the strong coupling expansion. We show using the example of a one-plaquette model that the stationary point equation for this action describes the weak coupling phase as well as the strong coupling phase. It is argued that such an equation predicts a phase transition for D-dimensional gauge theory, in accordance with Monte Carlo data. (orig.)
Gauge theories as theories of spontaneous breakdown
International Nuclear Information System (INIS)
Ivanov, E.A.; Ogievetsky, V.I.
1976-01-01
Any gauge theory is proved to arise from spontaneous breakdown of symmetry under certain infinite parameter group, the corresponding gauge field being the Goldstone field by which this breakdown is accompanied
Wetterich, C.
2018-06-01
We propose a closed gauge-invariant functional flow equation for Yang-Mills theories and quantum gravity that only involves one macroscopic gauge field or metric. It is based on a projection on physical and gauge fluctuations. Deriving this equation from a functional integral we employ the freedom in the precise choice of the macroscopic field and the effective average action in order to realize a closed and simple form of the flow equation.
Lauterbach, S.; Fina, M.; Wagner, W.
2018-04-01
Since structural engineering requires highly developed and optimized structures, the thickness dependency is one of the most controversially debated topics. This paper deals with stability analysis of lightweight thin structures combined with arbitrary geometrical imperfections. Generally known design guidelines only consider imperfections for simple shapes and loading, whereas for complex structures the lower-bound design philosophy still holds. Herein, uncertainties are considered with an empirical knockdown factor representing a lower bound of existing measurements. To fully understand and predict expected bearable loads, numerical investigations are essential, including geometrical imperfections. These are implemented into a stand-alone program code with a stochastic approach to compute random fields as geometric imperfections that are applied to nodes of the finite element mesh of selected structural examples. The stochastic approach uses the Karhunen-Loève expansion for the random field discretization. For this approach, the so-called correlation length l_c controls the random field in a powerful way. This parameter has a major influence on the buckling shape, and also on the stability load. First, the impact of the correlation length is studied for simple structures. Second, since most structures for engineering devices are more complex and combined structures, these are intensively discussed with the focus on constrained random fields for e.g. flange-web-intersections. Specific constraints for those random fields are pointed out with regard to the finite element model. Further, geometrical imperfections vanish where the structure is supported.
International Nuclear Information System (INIS)
Kuzio de Naray, Rachel; McGaugh, Stacy S.; Mihos, J. Christopher
2009-01-01
We model the Navarro-Frenk-White (NFW) potential to determine if, and under what conditions, the NFW halo appears consistent with the observed velocity fields of low surface brightness (LSB) galaxies. We present mock DensePak Integral Field Unit (IFU) velocity fields and rotation curves of axisymmetric and nonaxisymmetric potentials that are well matched to the spatial resolution and velocity range of our sample galaxies. We find that the DensePak IFU can accurately reconstruct the velocity field produced by an axisymmetric NFW potential and that a tilted-ring fitting program can successfully recover the corresponding NFW rotation curve. We also find that nonaxisymmetric potentials with fixed axis ratios change only the normalization of the mock velocity fields and rotation curves and not their shape. The shape of the modeled NFW rotation curves does not reproduce the data: these potentials are unable to simultaneously bring the mock data at both small and large radii into agreement with observations. Indeed, to match the slow rise of LSB galaxy rotation curves, a specific viewing angle of the nonaxisymmetric potential is required. For each of the simulated LSB galaxies, the observer's line of sight must be along the minor axis of the potential, an arrangement that is inconsistent with a random distribution of halo orientations on the sky.
Natural image sequences constrain dynamic receptive fields and imply a sparse code.
Häusler, Chris; Susemihl, Alex; Nawrot, Martin P
2013-11-06
In their natural environment, animals experience a complex and dynamic visual scenery. Under such natural stimulus conditions, neurons in the visual cortex employ a spatially and temporally sparse code. For the input scenario of natural still images, previous work demonstrated that unsupervised feature learning combined with the constraint of sparse coding can predict physiologically measured receptive fields of simple cells in the primary visual cortex. This convincingly indicated that the mammalian visual system is adapted to the natural spatial input statistics. Here, we extend this approach to the time domain in order to predict dynamic receptive fields that can account for both spatial and temporal sparse activation in biological neurons. We rely on temporal restricted Boltzmann machines and suggest a novel temporal autoencoding training procedure. When tested on a dynamic multi-variate benchmark dataset this method outperformed existing models of this class. Learning features on a large dataset of natural movies allowed us to model spatio-temporal receptive fields for single neurons. They resemble temporally smooth transformations of previously obtained static receptive fields and are thus consistent with existing theories. A neuronal spike response model demonstrates how the dynamic receptive field facilitates temporal and population sparseness. We discuss the potential mechanisms and benefits of a spatially and temporally sparse representation of natural visual input. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.