A note on the three dimensional sine--Gordon equation
Shariati, Ahmad
1996-01-01
Using a simple ansatz for the solutions of the three dimensional generalization of the sine--Gordon and Toda model introduced by Konopelchenko and Rogers, a class of solutions is found by elementary methods. It is also shown that these equations are not evolution equations in the sense that solution to the initial value problem is not unique.
New quasi-periodic waves of the (2+1)-dimensional sine-Gordon system
International Nuclear Information System (INIS)
Hu, H.C.; Lou, S.Y.
2005-01-01
New exact solutions of the well-known (2+1)-dimensional sine-Gordon system are studied by introducing the modified mapping relations between the cubic nonlinear Klein-Gordon and sine-Gordon equations. Two arbitrary functions are included into the Jacobi elliptic function solutions. By proper selections of the arbitrary functions, new quasi-periodic wave solutions are obtained and displayed graphically
Discrete mKdV and discrete sine-Gordon flows on discrete space curves
International Nuclear Information System (INIS)
Inoguchi, Jun-ichi; Kajiwara, Kenji; Matsuura, Nozomu; Ohta, Yasuhiro
2014-01-01
In this paper, we consider the discrete deformation of the discrete space curves with constant torsion described by the discrete mKdV or the discrete sine-Gordon equations, and show that it is formulated as the torsion-preserving equidistant deformation on the osculating plane which satisfies the isoperimetric condition. The curve is reconstructed from the deformation data by using the Sym–Tafel formula. The isoperimetric equidistant deformation of the space curves does not preserve the torsion in general. However, it is possible to construct the torsion-preserving deformation by tuning the deformation parameters. Further, it is also possible to make an arbitrary choice of the deformation described by the discrete mKdV equation or by the discrete sine-Gordon equation at each step. We finally show that the discrete deformation of discrete space curves yields the discrete K-surfaces. (paper)
Regularized integrable version of the one-dimensional quantum sine-Gordon model
International Nuclear Information System (INIS)
Japaridze, G.I.; Nersesyan, A.A.; Wiegmann, P.B.
1983-01-01
The authors derive a regularized exactly solvable version of the one-dimensional quantum sine-Gordon model proceeding from the exact solution of the U(1)-symmetric Thirring model. The ground state and the excitation spectrum are obtained in the region ν 2 < 8π. (Auth.)
From sine-Gordon to vacuumless systems in flat and curved spacetimes
Energy Technology Data Exchange (ETDEWEB)
Bazeia, D.; Moreira, D.C. [Universidade Federal da Paraiba, Departamento de Fisica, Joao Pessoa, PB (Brazil)
2017-12-15
In this work we start from the Higgs prototype model to introduce a new model, which makes a smooth transition between systems with well-located minima and systems that support no minima at all. We implement this possibility using the deformation procedure, which allows the obtaining a sine-Gordon-like model, controlled by a real parameter that gives rise to a family of models, reproducing the sine-Gordon and the so-called vacuumless models. We also study the thick brane scenarios associated with these models and investigate their stability and renormalization group flow. In particular, it is shown how gravity can change from the 5-dimensional warped geometry with a single extra dimension of infinite extent to the conventional 5-dimensional Minkowski geometry. (orig.)
International Nuclear Information System (INIS)
Chen Yong; Yan Zhenya
2005-01-01
In this paper (2 + 1)-dimensional Gardner equation is investigated using a sine-Gordon equation expansion method, which was presented via a generalized sine-Gordon reduction equation and a new transformation. As a consequence, it is shown that the method is more powerful to obtain many types of new doubly periodic solutions of (2 + 1)-dimensional Gardner equation. In particular, solitary wave solutions are also given as simple limits of doubly periodic solutions
Complex classical paths and the one-dimensional sine-Gordon system
International Nuclear Information System (INIS)
Millard, P.A.
1985-01-01
The semiclassical limit of the Green function for a particle in the one-dimensional sine-Gordon potential is obtained by summing over complex classical paths. The results are the same as those obtained in the less physically intuitive WKB approach. In addition to being of practical utility for solving quantum mechanical problems involving tunnelling, the classical path method may show how to deal with dense configuration of instantons. (orig.)
Second order phase transition in two dimensional sine-Gordon field theory - lattice model
International Nuclear Information System (INIS)
Babu Joseph, K.; Kuriakose, V.C.
1978-01-01
Two dimensional sine-Gordon (SG) field theory on a lattice is studied using the single-site basis variational method of Drell and others. The nature of the phase transition associated with the spontaneous symmetry breakdown in a SG field system is clarified to be of second order. A generalisation is offered for a SG-type field theory in two dimensions with a potential of the form [cossup(n)((square root of lambda)/m)phi-1].(author)
International Nuclear Information System (INIS)
Tian Ye; Chen Jing; Zhang Zhifei
2012-01-01
In this paper, the separation transformation approach is extended to the (N + 1)-dimensional dispersive double sine-Gordon equation arising in many physical systems such as the spin dynamics in the B phase of 3 He superfluid. This equation is first reduced to a set of partial differential equations and a nonlinear ordinary differential equation. Then the general solutions of the set of partial differential equations are obtained and the nonlinear ordinary differential equation is solved by F-expansion method. Finally, many new exact solutions of the (N + 1)-dimensional dispersive double sine-Gordon equation are constructed explicitly via the separation transformation. For the case of N > 2, there is an arbitrary function in the exact solutions, which may reveal more novel nonlinear structures in the high-dimensional dispersive double sine-Gordon equation.
Digging into the Elusive Localised Solutions of (2+1) Dimensional sine-Gordon Equation
Radha, R.; Senthil Kumar, C.
2018-05-01
In this paper, we revisit the (2+1) dimensional sine-Gordon equation analysed earlier [R. Radha and M. Lakshmanan, J. Phys. A Math. Gen. 29, 1551 (1996)] employing the Truncated Painlevé Approach. We then generate the solutions in terms of lower dimensional arbitrary functions of space and time. By suitably harnessing the arbitrary functions present in the closed form of the solution, we have constructed dromion solutions and studied their collisional dynamics. We have also constructed dromion pairs and shown that the dynamics of the dromion pairs can be turned ON or OFF desirably. In addition, we have also shown that the orientation of the dromion pairs can be changed. Apart from the above classes of solutions, we have also generated compactons, rogue waves and lumps and studied their dynamics.
Ring-shaped quasi-soliton solutions to the two-and three-dimensional Sine-Gordon equation
International Nuclear Information System (INIS)
Christiansen, P.L.; Olsen, O.H.
1979-01-01
Ring-shaped solitary wave solutions to the Sine-Gordon equation in two and three spatial dimensions are investigated by numerical computation. Each expanding wave exhibits a return effect. The reflection of the shrinking wave at the singularity at the center of the wave is investigated in a particular case. Collision experiments in numero for expanding and shrinking concentric ring waves show that the solutions possess quasisoliton properties. A Baecklund transformation for the non-symmetric three-dimensional case is given. (Auth.)
International Nuclear Information System (INIS)
Kaelbermann, G
2004-01-01
Nonperturbative, oscillatory, winding number 1 solutions of the sine-Gordon equation are presented and studied numerically. We call these nonperturbative shape modes wobble solitons. Perturbed sine-Gordon kinks are found to decay to wobble solitons
Gravity localization in sine-Gordon braneworlds
International Nuclear Information System (INIS)
Cruz, W.T.; Maluf, R.V.; Sousa, L.J.S.; Almeida, C.A.S.
2016-01-01
In this work we study two types of five-dimensional braneworld models given by sine-Gordon potentials. In both scenarios, the thick brane is generated by a real scalar field coupled to gravity. We focus our investigation on the localization of graviton field and the behaviour of the massive spectrum. In particular, we analyse the localization of massive modes by means of a relative probability method in a Quantum Mechanics context. Initially, considering a scalar field sine-Gordon potential, we find a localized state to the graviton at zero mode. However, when we consider a double sine-Gordon potential, the brane structure is changed allowing the existence of massive resonant states. The new results show how the existence of an internal structure can aid in the emergence of massive resonant modes on the brane.
Critical boundary sine-Gordon revisited
International Nuclear Information System (INIS)
Hasselfield, M.; Lee, Taejin; Semenoff, G.W.; Stamp, P.C.E.
2006-01-01
We revisit the exact solution of the two space-time dimensional quantum field theory of a free massless boson with a periodic boundary interaction and self-dual period. We analyze the model by using a mapping to free fermions with a boundary mass term originally suggested in Ref. [J. Polchinski, L. Thorlacius, Phys. Rev. D 50 (1994) 622]. We find that the entire SL (2, C) family of boundary states of a single boson are boundary sine-Gordon states and we derive a simple explicit expression for the boundary state in fermion variables and as a function of sine-Gordon coupling constants. We use this expression to compute the partition function. We observe that the solution of the model has a strong-weak coupling generalization of T-duality. We then examine a class of recently discovered conformal boundary states for compact bosons with radii which are rational numbers times the self-dual radius. These have simple expression in fermion variables. We postulate sine-Gordon-like field theories with discrete gauge symmetries for which they are the appropriate boundary states
Exact solutions to sine-Gordon-type equations
International Nuclear Information System (INIS)
Liu Shikuo; Fu Zuntao; Liu Shida
2006-01-01
In this Letter, sine-Gordon-type equations, including single sine-Gordon equation, double sine-Gordon equation and triple sine-Gordon equation, are systematically solved by Jacobi elliptic function expansion method. It is shown that different transformations for these three sine-Gordon-type equations play different roles in obtaining exact solutions, some transformations may not work for a specific sine-Gordon equation, while work for other sine-Gordon equations
Generalized sine-Gordon solitons
International Nuclear Information System (INIS)
Santos, C dos; Rubiera-Garcia, D
2011-01-01
In this paper, we construct analytical self-dual soliton solutions in (1+1) dimensions for two families of models which can be seen as generalizations of the sine-Gordon system but where the kinetic term is non-canonical. For that purpose we use a projection method applied to the sine-Gordon soliton. We focus our attention on the wall and lump-like soliton solutions of these k-field models. These solutions and their potentials reduce to those of the Klein-Gordon kink and the standard lump for the case of a canonical kinetic term. As we increase the nonlinearity on the kinetic term the corresponding potentials get modified and the nature of the soliton may change, in particular, undergoing a topology modification. The procedure constructed here is shown to be a sort of generalization of the deformation method for a specific class of k-field models. (paper)
Exact, multiple soliton solutions of the double sine Gordon equation
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Burt, P.B.
1978-01-01
Exact, particular solutions of the double sine Gordon equation in n dimensional space are constructed. Under certain restrictions these solutions are N solitons, where N <= 2q - 1 and q is the dimensionality of space-time. The method of solution, known as the base equation technique, relates solutions of nonlinear partial differential equations to solutions of linear partial differential equations. This method is reviewed and its applicability to the double sine Gordon equation shown explicitly. The N soliton solutions have the remarkable property that they collapse to a single soliton when the wave vectors are parallel. (author)
Comparison of renormalization group schemes for sine-Gordon-type models
International Nuclear Information System (INIS)
Nandori, I.; Nagy, S.; Sailer, K.; Trombettoni, A.
2009-01-01
The scheme dependence of the renormalization group (RG) flow has been investigated in the local potential approximation for two-dimensional periodic, sine-Gordon type field-theoretic models discussing the applicability of various functional RG methods in detail. It was shown that scheme-independent determination of such physical parameters is possible as the critical frequency (temperature) at which Kosterlitz-Thouless-Berezinskii type phase transition takes place in the sine-Gordon and the layered sine-Gordon models, and the critical ratio characterizing the Ising-type phase transition of the massive sine-Gordon model. For the latter case, the Maxwell construction represents a strong constraint on the RG flow, which results in a scheme-independent infrared value for the critical ratio. For the massive sine-Gordon model also the shrinking of the domain of the phase with spontaneously broken periodicity is shown to take place due to the quantum fluctuations.
International Nuclear Information System (INIS)
Cule, D.; Shapir, Y.
1995-01-01
The dynamics of the random-phase sine-Gordon model, which describes two-dimensional vortex-glass arrays and crystalline surfaces on disordered substrates, is investigated using the self-consistent Hartree approximation. The fluctuation-dissipation theorem is violated below the critical temperature T c for large time t>t * where t * diverges in the thermodynamic limit. While above T c the averaged autocorrelation function diverges as Tln(t), for T c it approaches a finite value q * ∼1/(T c -T) as q(t)=q * -c(t/t * ) -ν (for t→t * ) where ν is a temperature-dependent exponent. On larger time scales t>t * the dynamics becomes nonergodic. The static correlations behave as ∼Tln|rvec x| for T>T c and for T c when x * with ξ * ∼exp{A/(T c -T)}. For scales x>ξ * , they behave as ∼m -1 Tln|rvec x| where m∼T/T c near T c , in general agreement with the variational replica-symmetry breaking approach and with recent simulations of the disordered-substrate surface. For strong coupling the transition becomes first order
Rotationally symmetric numerical solutions to the sine-Gordon equation
DEFF Research Database (Denmark)
Olsen, O. H.; Samuelsen, Mogens Rugholm
1981-01-01
We examine numerically the properties of solutions to the spherically symmetric sine-Gordon equation given an initial profile which coincides with the one-dimensional breather solution and refer to such solutions as ring waves. Expanding ring waves either exhibit a return effect or expand towards...
Mass renormalization in sine-Gordon model
International Nuclear Information System (INIS)
Xu Bowei; Zhang Yumei
1991-09-01
With a general gaussian wave functional, we investigate the mass renormalization in the sine-Gordon model. At the phase transition point, the sine-Gordon system tends to a system of massless free bosons which possesses conformal symmetry. (author). 8 refs, 1 fig
Scaling in the sine-Gordon theory
International Nuclear Information System (INIS)
Ben-Abraham, S.I.
1976-01-01
It is shown that both the classical and the quantum sine-Gordon theory depend on a single scaling parameter and therefore the coupling constant cannot be freely chosen. To introduce a meaningful coupling constant it is proposed to include higher Fourier terms in the sine-Gordon potential. The two term case is exactly solvable. (Auth.)
Gauge symmetry of Sine-Gordon model
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Shen Jian-Min; Li Kang; Sheng Zhengmao.
1993-03-01
We have found that the strong coupled interaction of Sine-Gordon model is related to its weak coupled interaction by the su(2) gauge transformation. We therefore develop a semi-classical approach to deal with the infrared divergence in the conventional perturbation theory of the Hamiltonian of the quantum Sine-Gordon model. (author). 10 refs
Critical properties of the double-frequency sine-Gordon model with applications
International Nuclear Information System (INIS)
Fabrizio, M.; Gogolin, A.O.; Nersesyan, A.A.
2000-01-01
We study the properties of the double-frequency sine-Gordon model in the vicinity of the Ising quantum phase transition displayed by this model. Using a mapping onto a generalized lattice quantum Ashkin-Teller model, we obtain critical and nearly-off-critical correlation functions of various operators. We discuss applications of the double-sine-Gordon model to one-dimensional physical systems, like spin chains in a staggered external field and interacting electrons in a staggered potential
Light-front quantization of the sine-Gordon model
International Nuclear Information System (INIS)
Burkardt, M.
1993-01-01
It is shown how to modify the canonical light-front quantization of the (1+1)-dimensional sine-Gordon model such that the zero-mode problem of light-front quantization is avoided. The canonical sine-Gordon Lagrangian is replaced by an effective Lagrangian which does not lead to divergences as k + =(k 0 +k 1 )/ √2 →0. After canonically quantizing the effective Lagrangian, one obtains the effective light-front Hamiltonian which agrees with the naive light-front (LF) Hamiltonian, up to one additional renormalization. The spectrum of the effective LF Hamiltonian is determined using discrete light-cone quantization and agrees with results from equal-time quantization
An integrable noncommutative version of the sine-Gordon system
International Nuclear Information System (INIS)
Grisaru, Marcus T.; Penati, Silvia
2003-01-01
Using the bicomplex approach we discuss an integrable noncommutative system in two-dimensional Euclidean space. It is described by an equation of motion which reduces to the ordinary sine-Gordon equation when the noncommutation parameter is removed, plus a constraint equation which is nontrivial only in the noncommutative case. The implications of this constraint, which is required by integrability but seems to reduce the space of classical solutions, remain to be understood. We show that the system has an infinite number of conserved currents and we give the general recursive relation for constructing them. For the particular cases of lower spin nontrivial currents we work out the explicit expressions and perform a direct check of their conservation. These currents reduce to the usual sine-Gordon currents in the commutative limit. We find classical 'localized' solutions to first order in the noncommutativity parameter and describe the Backlund transformations for our system. Finally, we comment on the relation of our noncommutative system to the commutative sine-Gordon system
On the supersymmetric sine-Gordon model
International Nuclear Information System (INIS)
Hruby, J.
1977-01-01
The sine-Gordon model as the theory of a massless scalar field in one space and one time dimension with interaction Lagrangian density proportional to cosβsub(phi) is generalized for a scalar superfield and it is shown that the solution of the supercovariant sine-Gordon equation is the ''supersoliton'', it is the superfield, which has all ordinary fields in two dimensions as a type of the soliton solution. We also obtain the massive Thirring model and the new equations of motion coupling the Fermi field and the Bose field. The notice about supersymmetric ''SLAC-BAG'' model is done
The complex sine-Gordon model on a half line
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Tzamtzis, Georgios
2003-01-01
In this thesis, we study the complex sine-Gordon model on a half line. The model in the bulk is an integrable (1+1) dimensional field theory which is U(1) gauge invariant and comprises a generalisation of the sine-Gordon theory. It accepts soliton and breather solutions. By introducing suitably selected boundary conditions we may consider the model on a half line. Through such conditions the model can be shown to remain integrable and various aspects of the boundary theory can be examined. The first chapter serves as a brief introduction to some basic concepts of integrability and soliton solutions. As an example of an integrable system with soliton solutions, the sine-Gordon model is presented both in the bulk and on a half line. These results will serve as a useful guide for the model at hand. The introduction finishes with a brief overview of the two methods that will be used on the fourth chapter in order to obtain the quantum spectrum of the boundary complex sine-Gordon model. In the second chapter the model is properly introduced along with a brief literature review. Different realisations of the model and their connexions are discussed. The vacuum of the theory is investigated. Soliton solutions are given and a discussion on the existence of breathers follows. Finally the collapse of breather solutions to single solitons is demonstrated and the chapter concludes with a different approach to the breather problem. In the third chapter, we construct the lowest conserved currents and through them we find suitable boundary conditions that allow for their conservation in the presence of a boundary. The boundary term is added to the Lagrangian and the vacuum is reexamined in the half line case. The reflection process of solitons from the boundary is studied and the time-delay is calculated. Finally we address the existence of boundary-bound states. In the fourth chapter we study the quantum complex sine-Gordon model. We begin with a brief overview of the theory in
The sine-Gordon model revisited I
Energy Technology Data Exchange (ETDEWEB)
Niccoli, G.; Teschner, J.
2009-10-15
We study integrable lattice regularizations of the Sine-Gordon model with the help of the Separation of Variables method of Sklyanin and the Baxter Q-operators. This allows us to characterize the spectrum (eigenvalues and eigenstates) completely in terms of polynomial solutions of the Baxter equation with certain properties. This result is analogous to the completeness of the Bethe ansatz. (orig.)
Oscillating and rotating sine-Gordon system
DEFF Research Database (Denmark)
Olsen, O. H.; Samuelsen, Mogens Rugholm
1986-01-01
The interaction between a 2π kink and the background or vacuum is investigated in the pure sine-Gordon system. For an oscillating background (i.e., the k=0 part of the phonon spectrum) the 2π kink oscillates, while for increasing or decreasing vacuum two phenomena have been observed, depending...
Roughening in random sine-Gordon systems
International Nuclear Information System (INIS)
Schwartz, M.; Nattermann, T.
1991-01-01
We consider the spatial correlations of the optimal solutions of the random sine-Gordon equation as an example of the usefulness of a very simple ansatz relating the Fourier transforms of certain functions of the field Φ to the Fourier transform of the random fields. The dramatic change in the correlations when going from above to below two dimensions is directly attributed to the transfer from dominance of long range fluctuations of the randomness to the dominance of short range fluctuations. (orig.)
Group-theoretical aspects of the discrete sine-Gordon equation
International Nuclear Information System (INIS)
Orfanidis, S.J.
1980-01-01
The group-theoretical interpretation of the sine-Gordon equation in terms of connection forms on fiber bundles is extended to the discrete case. Solutions of the discrete sine-Gordon equation induce surfaces on a lattice in the SU(2) group space. The inverse scattering representation, expressing the parallel transport of fibers, is implemented by means of finite rotations. Discrete Baecklund transformations are realized as gauge transformations. The three-dimensional inverse scattering representation is used to derive a discrete nonlinear sigma model, and the corresponding Baecklund transformation and Pohlmeyer's R transformation are constructed
Vacuum instability in the quantum sine-gordon model
International Nuclear Information System (INIS)
Bogolyubov, N.M.; Izergin, A.G.; Korepin, V.E.
1985-01-01
A review is given of papers dealing with regularization of the sine-Gordon model and the construction of the integrable lattice sine-Gordon (LSG) model. The regularization by means of LSG model seems to be much more natural as it is done in terms of initial boson fields entering Hamiltonian which describes relativistic scalar field with essentially nonlinear self-interaction. Changes in physical vacuum due to regularizations of the sine-Gordon model is shown
Closed-form expressions for integrals of MKdV and sine-Gordon maps
International Nuclear Information System (INIS)
Kamp, Peter H van der; Rojas, O; Quispel, G R W
2007-01-01
We present closed-form expressions for approximately N integrals of 2N-dimensional maps. The maps are obtained by travelling wave reductions of the modified Korteweg-de Vries equation and of the sine-Gordon equation, respectively. We provide the integrating factors corresponding to the integrals. Moreover we show how the integrals and the integrating factors relate to the staircase method
A novel singular pattern in the sine-Gordon equation
International Nuclear Information System (INIS)
Huang, Debin
2003-01-01
By the scatter problem and the Backlund transformation of the sine-Gordon equation, we find a novel solution with the singularity of jumping phenomenon, which displays pattern structure similar respectively to soliton, kink, anti-kink and double pole solution with the different choice of the purely imaginary spectrum of the sine-Gordon equation
Bunched soliton states in weakly coupled sine-Gordon systems
DEFF Research Database (Denmark)
Grønbech-Jensen, N.; Samuelsen, Mogens Rugholm; Lomdahl, P. S.
1990-01-01
The interaction between solitons of two weakly coupled sine-Gordon systems is considered. In particular, the stability of bunched states is investigated, and perturbation results are compared with numerical results.......The interaction between solitons of two weakly coupled sine-Gordon systems is considered. In particular, the stability of bunched states is investigated, and perturbation results are compared with numerical results....
Correlations between chaos in a perturbed sine-Gordon equation and a truncated model system
International Nuclear Information System (INIS)
Bishop, A.R.; Flesch, R.; Forests, M.G.; Overman, E.A.
1990-01-01
The purpose of this paper is to present a first step toward providing coordinates and associated dynamics for low-dimensional attractors in nearly integrable partial differential equations (pdes), in particular, where the truncated system reflects salient geometric properties of the pde. This is achieved by correlating: (1) numerical results on the bifurcations to temporal chaos with spatial coherence of the damped, periodically forced sine-Gordon equation with periodic boundary conditions; (2) an interpretation of the spatial and temporal bifurcation structures of this perturbed integrable system with regard to the exact structure of the sine-Gordon phase space; (3) a model dynamical systems problem, which is itself a perturbed integrable Hamiltonian system, derived from the perturbed sine-Gordon equation by a finite mode Fourier truncation in the nonlinear Schroedinger limit; and (4) the bifurcations to chaos in the truncated phase space. In particular, a potential source of chaos in both the pde and the model ordinary differential equation systems is focused on: the existence of homoclinic orbits in the unperturbed integrable phase space and their continuation in the perturbed problem. The evidence presented here supports the thesis that the chaotic attractors of the weakly perturbed periodic sine-Gordon system consists of low-dimensional metastable attacking states together with intermediate states that are O(1) unstable and correspond to homoclinic states in the integrable phase space. It is surmised that the chaotic dynamics on these attractors is due to the perturbation of these homocline integrable configurations
Directory of Open Access Journals (Sweden)
Kenichi Kondo
2013-11-01
Full Text Available Ultradiscretization with negative values is a long-standing problem and several attempts have been made to solve it. Among others, we focus on the symmetrized max-plus algebra, with which we ultradiscretize the discrete sine-Gordon equation. Another ultradiscretization of the discrete sine-Gordon equation has already been proposed by previous studies, but the equation and the solutions obtained here are considered to directly correspond to the discrete counterpart. We also propose a noncommutative discrete analogue of the sine-Gordon equation, reveal its relations to other integrable systems including the noncommutative discrete KP equation, and construct multisoliton solutions by a repeated application of Darboux transformations. Moreover, we derive a noncommutative ultradiscrete analogue of the sine-Gordon equation and its 1-soliton and 2-soliton solutions, using the symmetrized max-plus algebra. As a result, we have a complete set of commutative and noncommutative versions of continuous, discrete, and ultradiscrete sine-Gordon equations.
Zero temperature landscape of the random sine-Gordon model
International Nuclear Information System (INIS)
Sanchez, A.; Bishop, A.R.; Cai, D.
1997-01-01
We present a preliminary summary of the zero temperature properties of the two-dimensional random sine-Gordon model of surface growth on disordered substrates. We found that the properties of this model can be accurately computed by using lattices of moderate size as the behavior of the model turns out to be independent of the size above certain length (∼ 128 x 128 lattices). Subsequently, we show that the behavior of the height difference correlation function is of (log r) 2 type up to a certain correlation length (ξ ∼ 20), which rules out predictions of log r behavior for all temperatures obtained by replica-variational techniques. Our results open the way to a better understanding of the complex landscape presented by this system, which has been the subject of very many (contradictory) analysis
Sine-Gordon mean field theory of a Coulomb gas
Energy Technology Data Exchange (ETDEWEB)
Diehl, Alexandre; Barbosa, Marcia C.; Levin, Yan
1997-12-31
Full text. The Coulomb gas provides a paradigm for the study of various models of critical phenomena. In particular, it is well known that the two dimensional (2 D). Coulomb gas can be directly used to study the superfluidity transition in {sup 4} He films, arrays of Josephson junctions, roughening transition, etc. Not withstanding its versatility, our full understanding of the most basic model of Coulomb gas, namely an ensemble of hard spheres carrying either positive or negative charges at their center, is still lacking. It is now well accepted that at low density the two dimensional plasma of equal number of positive and negative particles undergoes a Kosterlitz-Thouless (KT) metal insulator transition. This transition is of an infinite order and is characterized by a diverging Debye screening length. As the density of particles increases, the validity of the KT theory becomes questionable and the possibility of the KT transition being replaced by some kind of first order discontinuity has been speculated for a long time. In this work sine-Gordon field theory is used to investigate the phase diagram of a neutral Coulomb gas. A variational mean-field free energy is constructed and the corresponding phase diagrams in two and three dimensions are obtained. When analyzed in terms of chemical potential, the sine-Gordon theory predicts the phase diagram topologically identical to the Monte Carlo simulations and a recently developed Debye-Huckel-Bjerrum theory. In 2D, we find that the infinite-order Kosterlitz-Thouless line terminates in a tricritical point, after which the metal-insulator transition becomes first order. However, when the transformation from chemical potential to the density is made the whole insulating phase is mapped onto zero density. (author)
Bunched soliton states in weakly coupled sine-Gordon systems
International Nuclear Information System (INIS)
Gronbech-Jensen, N.; Samuelsen, M.R.; Lomdahl, P.S.; Blackburn, J.A.
1990-01-01
The interaction between solitons of two weakly coupled sine-Gordon systems is considered. In particular, the stability of bunched states is investigated, and perturbation results are compared with numerical results
Solutions of the finite type of Sine-Gordon equation
International Nuclear Information System (INIS)
Zhao Guosong
1998-01-01
We use the technique of differential geometry to prove that the solutions of finite type of the sine-Gordon equation φ xx - φ yy = sin φ cosφ can be obtained from a system of ordinary differential equations
Carpentier, David
1998-01-01
Using the renormalisation group (RG) we study two dimensional electromagnetic coulomb gas and extended Sine-Gordon theories invariant under the modular group SL(2,Z). The flow diagram is established from the scaling equations, and we derive the critical behaviour at the various transition points of the diagram. Following proposal for a SL(2,Z) duality between different quantum Hall fluids, we discuss the analogy between this flow and the global quantum Hall phase diagram.
Confinement, solitons and the equivalence between the sine-Gordon and massive Thirring models
International Nuclear Information System (INIS)
Blas Achic, H.S.; Ferreira, L.A.
2000-01-01
We consider a two-dimensional integrable and conformally invariant field theory possessing two Dirac spinors and three scalar fields. The interaction couples bilinear terms in the spinors to exponentials of the scalars. Its integrability properties are based on the sl(2) affine Kac-Moody algebra, and it is a simple example of the so-called conformal affine Toda theories coupled to matter fields. We show, using bosonization techniques, that the classical equivalence between a U(1) Noether current and the topological current holds true at the quantum level, and then leads to a bag model like mechanism for the confinement of the spinor fields inside the solitons. By bosonizing the spinors we show that the theory decouples into a sine-Gordon model and free scalars. We construct the two-soliton solutions and show that their interactions lead to the same time delays as those for the sine-Gordon solitons. The model provides a good laboratory to test duality ideas in the context of the equivalence between the sine-Gordon and Thirring theories
Abundant Interaction Solutions of Sine-Gordon Equation
Directory of Open Access Journals (Sweden)
DaZhao Lü
2012-01-01
Full Text Available With the help of computer symbolic computation software (e.g., Maple, abundant interaction solutions of sine-Gordon equation are obtained by means of a constructed Wronskian form expansion method. The method is based upon the forms and structures of Wronskian solutions of sine-Gordon equation, and the functions used in the Wronskian determinants do not satisfy linear partial differential equations. Such interaction solutions are difficultly obtained via other methods. And the method can be automatically carried out in computer.
International Nuclear Information System (INIS)
Faber, M.; Ivanov, A.N.
2001-01-01
We investigate the equivalence between Thirring model and sine-Gordon model in the chirally broken phase of the Thirring model. This is unlike all other available approaches where the fermion fields of the Thirring model were quantized in the chiral symmetric phase. In the path integral approach we show that the bosonized version of the massless Thirring model is described by a quantum field theory of a massless scalar field and exactly solvable, and the massive Thirring model bosonizes to the sine-Gordon model with a new relation between the coupling constants. We show that the non-perturbative vacuum of the chirally broken phase in the massless Thirring model can be described in complete analogy with the BCS ground state of superconductivity. The Mermin-Wagner theorem and Coleman's statement concerning the absence of Goldstone bosons in the 1+1-dimensional quantum field theories are discussed. We investigate the current algebra in the massless Thirring model and give a new value of the Schwinger term. We show that the topological current in the sine-Gordon model coincides with the Noether current responsible for the conservation of the fermion number in the Thirring model. This allows one to identify the topological charge in the sine-Gordon model with the fermion number. (orig.)
Nonlinear dynamics of a parametrically driven sine-Gordon system
DEFF Research Database (Denmark)
Grønbech-Jensen, Niels; Kivshar, Yuri S.; Samuelsen, Mogens Rugholm
1993-01-01
We consider a sine-Gordon system, driven by an ac parametric force in the presence of loss. It is demonstrated that a breather can be maintained in a steady state at half of the external frequency. In the small-amplitude limit the effect is described by an effective nonlinear Schrodinger equation...
On Darboux transformation of the supersymmetric sine-Gordon equation
International Nuclear Information System (INIS)
Siddiq, M; Hassan, M; Saleem, U
2006-01-01
Darboux transformation is constructed for superfields of the super sine-Gordon equation and the superfields of the associated linear problem. The Darboux transformation is shown to be related to the super Baecklund transformation and is further used to obtain N super soliton solutions
Phonons and solitons in the "thermal" sine-Gordon system
DEFF Research Database (Denmark)
Salerno, Mario; Jørgensen, E.; Samuelsen, Mogens Rugholm
1984-01-01
Standard methods of stochastic processes are used to study the coupling of the sine-Gordon system with a heat reservoir. As a result we find thermal phonons with an average energy of kB T per mode. The translational mode (zero mode) is found to carry an average energy of 1 / 2kBT. This last value...
Experimental Investigation of Trapped Sine-Gordon Solitons
DEFF Research Database (Denmark)
Davidson, A.; Dueholm, B.; Kryger, B.
1985-01-01
We have observed for the first time a single sine-Gordon soliton trapped in an annular Josephson junction. This system offers a unique possibility to study undisturbed soliton motion. In the context of perturbation theory, the soliton may be viewed as a relativistic particle moving under a uniform...
Soliton annihilation in the perturbed sine-Gordon system
DEFF Research Database (Denmark)
Pedersen, Niels Falsig; Samuelsen, Mogens Rugholm; Welner, D.
1984-01-01
Fluxon-antifluxon annihilation in the perturbed sine-Gordon equation with loss and driving terms is investigated. For the infinite line we find a simple analytic expression for the threshold driving term corresponding to annihilation. With the application of the results to a Josephson junction...
Boson-soliton scattering in the sine-Gordon model
International Nuclear Information System (INIS)
Lowe, M.
1979-01-01
In this paper the author calculates the boson-soliton scattering amplitudes for various processes in the sine-Gordon model to obtain results in agreement with the prediction of no-particle production and equality of ingoing and outgoing sets of momenta. (Auth.)
Quantum Hall bilayers and the chiral sine-Gordon equation
International Nuclear Information System (INIS)
Naud, J.D.; Pryadko, Leonid P.; Sondhi, S.L.
2000-01-01
The edge state theory of a class of symmetric double-layer quantum Hall systems with interlayer electron tunneling reduces to the sum of a free field theory and a field theory of a chiral Bose field with a self-interaction of the sine-Gordon form. We argue that the perturbative renormalization group flow of this chiral sine-Gordon theory is distinct from the standard (non-chiral) sine-Gordon theory, contrary to a previous assertion by Renn, and that the theory is manifestly sensible only at a discrete set of values of the inverse period of the cosine interaction (β-circumflex). We obtain exact solutions for the spectra and correlation functions of the chiral sine-Gordon theory at the two values of β-circumflex at which electron tunneling in bilayers is not irrelevant. Of these, the marginal case (β-circumflex 2 =4) is of greatest interest: the spectrum of the interacting theory is that of two Majorana fermions with different, dynamically generated, velocities. For the experimentally observed bilayer 331 state at filling factor 1/2, this implies the trifurcation of electrons added to the edge. We also present a method for fermionizing the theory at the discrete points (β-circumflex 2 is an element of Z + ) by the introduction of auxiliary degrees of freedom that could prove useful in other problems involving quantum Hall multi-layers
Perturbation analysis of a parametrically changed sine-Gordon equation
DEFF Research Database (Denmark)
Sakai, S.; Samuelsen, Mogens Rugholm; Olsen, O. H.
1987-01-01
A long Josephson junction with a spatially varying inductance is a physical manifestation of a modified sine-Gordon equation with parametric perturbation. Soliton propagation in such Josephson junctions is discussed. First, for an adiabatic model where the inductance changes smoothly compared...
Homoclinic tubes and chaos in perturbed sine-Gordon equation
International Nuclear Information System (INIS)
Li, Y. Charles
2004-01-01
Sine-Gordon equation under a quasi-periodic perturbation or a chaotic perturbation is studied. Existence of a homoclinic tube is proved. Established are chaos associated with the homoclinic tube, and 'chaos cascade' referring to the embeddings of smaller scale chaos in larger scale chaos
The sine-Gordon model in the presence of defects
International Nuclear Information System (INIS)
Avan, Jean; Doikou, Anastasia
2013-01-01
The sine-Gordon model in the presence of dynamical integrable defects is investigated. This is an application of the algebraic formulation introduced for integrable defects in earlier works. The quantities in involution as well as the associated Lax pairs are explicitly extracted. Integrability i also shown using certain sewing constraints, which emerge as suitable continuity conditions.
Renormalization of the Sine-Gordon model and nonconservation of the kink current
International Nuclear Information System (INIS)
Huang, K.; Polonyi, J.
1991-01-01
The authors of this paper renormalize the (1 + 1)-dimensional sine-Gordon model by placing it on a Euclidean lattice, and study the renormalization group flow. The authors start with a compactified theory with controllable vortex activity. In the continuum limit the theory has a phase in which the kink current is anomalous, with divergence given by the vortex density. The phase structure is quite complicated. Roughly speaking, the system is normal for small coupling T. At the Kosterlitz-Thouless point T = π/2, the current can become anomalous. At the Coleman point T = 8π either the current becomes anomalous or the theory becomes trivial
Sine-Gordon breather form factors and quantum field equations
International Nuclear Information System (INIS)
Babujian, H; Karowski, M
2002-01-01
Using the results of previous investigations on sine-Gordon form factors, exact expressions of all breather matrix elements are obtained for several operators: all powers of the fundamental Bose field, general exponentials of it, the energy-momentum tensor and all higher currents. Formulae for the asymptotic behaviour of bosonic form factors are presented which are motivated by Weinberg's power counting theorem in perturbation theory. It is found that the quantum sine-Gordon field equation holds, and an exact relation between the 'bare' mass and the renormalized mass is obtained. Also a quantum version of a classical relation for the trace of the energy-momentum is proved. The eigenvalue problem for all higher conserved charges is solved. All results are compared with perturbative Feynman graph expansions and full agreement is found
Invariant solutions of the supersymmetric sine-Gordon equation
International Nuclear Information System (INIS)
Grundland, A M; Hariton, A J; Snobl, L
2009-01-01
A comprehensive symmetry analysis of the N=1 supersymmetric sine-Gordon equation is performed. Two different forms of the supersymmetric system are considered. We begin by studying a system of partial differential equations corresponding to the coefficients of the various powers of the anticommuting independent variables. Next, we consider the super-sine-Gordon equation expressed in terms of a bosonic superfield involving anticommuting independent variables. In each case, a Lie (super)algebra of symmetries is determined and a classification of all subgroups having generic orbits of codimension 1 in the space of independent variables is performed. The method of symmetry reduction is systematically applied in order to derive invariant solutions of the supersymmetric model. Several types of algebraic, hyperbolic and doubly periodic solutions are obtained in explicit form.
Thermodynamic Bethe ansatz for boundary sine-Gordon model
International Nuclear Information System (INIS)
Lee, Taejun; Rim, Chaiho
2003-01-01
(R-channel) TBA is elaborated to find the effective central charge dependence on the boundary parameters for the massless boundary sine-Gordon model with the coupling constant (8π)/β 2 =1+λ with λ a positive integer. Numerical analysis of the massless boundary TBA demonstrates that at an appropriate boundary parameter range (cusp point) there exists a singularity crossing phenomena and this effect should be included in TBA to have the right behavior of the effective central charge
Exact solutions to some modified sine-Gordon equations
International Nuclear Information System (INIS)
Saermark, K.
1983-01-01
Exact, translational solutions to a number of modified sine-Gordon equations are presented. In deriving the equations and the solutions use is made of results from the theory of ordinary differential equations without moving critical points as given by Ince. It is found that kink-like solutions exist also in cases where the coefficients of the trigonometric terms are space- and time-dependent. (Auth.)
The elliptic sine-Gordon equation in a half plane
International Nuclear Information System (INIS)
Pelloni, B; Pinotsis, D A
2010-01-01
We consider boundary value problems for the elliptic sine-Gordon equation posed in the half plane y > 0. This problem was considered in Gutshabash and Lipovskii (1994 J. Math. Sci. 68 197–201) using the classical inverse scattering transform approach. Given the limitations of this approach, the results obtained rely on a nonlinear constraint on the spectral data derived heuristically by analogy with the linearized case. We revisit the analysis of such problems using a recent generalization of the inverse scattering transform known as the Fokas method, and show that the nonlinear constraint of Gutshabash and Lipovskii (1994 J. Math. Sci. 68 197–201) is a consequence of the so-called global relation. We also show that this relation implies a stronger constraint on the spectral data, and in particular that no choice of boundary conditions can be associated with a decaying (possibly mod 2π) solution analogous to the pure soliton solutions of the usual, time-dependent sine-Gordon equation. We also briefly indicate how, in contrast to the evolutionary case, the elliptic sine-Gordon equation posed in the half plane does not admit linearisable boundary conditions
Low-mode truncation methods in the sine-Gordon equation
International Nuclear Information System (INIS)
Xiong Chuyu.
1991-01-01
In this dissertation, the author studies the chaotic and coherent motions (i.e., low-dimensional chaotic attractor) in some near integrable partial differential equations, particularly the sine-Gordon equation and the nonlinear Schroedinger equation. In order to study the motions, he uses low mode truncation methods to reduce these partial differential equations to some truncated models (low-dimensional ordinary differential equations). By applying many methods available to low-dimensional ordinary differential equations, he can understand the low-dimensional chaotic attractor of PDE's much better. However, there are two important questions one needs to answer: (1) How many modes is good enough for the low mode truncated models to capture the dynamics uniformly? (2) Is the chaotic attractor in a low mode truncated model close to the chaotic attractor in the original PDE? And how close is? He has developed two groups of powerful methods to help to answer these two questions. They are the computation methods of continuation and local bifurcation, and local Lyapunov exponents and Lyapunov exponents. Using these methods, he concludes that the 2N-nls ODE is a good model for the sine-Gordon equation and the nonlinear Schroedinger equation provided one chooses a 'good' basis and uses 'enough' modes (where 'enough' depends on the parameters of the system but is small for the parameter studied here). Therefore, one can use 2N-nls ODE to study the chaos of PDE's in more depth
Semiclassical approach to the quantization of the periodic solutions of the sine-Gordon equation
International Nuclear Information System (INIS)
Ghika, G.; Visinescu, M.
1978-01-01
The periodic solutions of the sine-Gordon equation are proved to be singular. For the semiclassical quantization of the periodic solutions we calculate the fluctuations around them and we use the path integrals in the Gaussian approximation in order to obtain the bound states of the sine-Gordon field equation. (author)
On a rigorously classical approach to the Sine-Gordon theory
International Nuclear Information System (INIS)
Ulmer, W.
1979-01-01
It is shown that the continuum limit of an infinite set of coupled pendula yields the Sine-Gordon theory. The extension of the model to more dimensions with respect to the propagation yields a generalized Sine-Gordon equation for vector fields, containing Proca equations as a first order approximation. (author)
Extended sine-Gordon Equation Method and Its Application to Maccari's System
International Nuclear Information System (INIS)
Song Lina; Zhang Hongqing
2005-01-01
An extended sine-Gordon equation method is proposed to construct exact travelling wave solutions to Maccari's equation based upon a generalized sine-Gordon equation. It is shown that more new travelling wave solutions can be found by this new method, which include bell-shaped soliton solutions, kink-shaped soliton solutions, periodic wave solution, and new travelling waves.
International Nuclear Information System (INIS)
Skagerstam, B.K.
1976-01-01
We discuss a generalization of the conventional sine-Gordon quantum field theory by using methods recently developed by Coleman. As a result we can argue that the equivalence between the sine-Gordon theory and the massive Thirring model is unaffected if we perturb the sine-Gordon Hamiltonian by a bounded perturbation consisting of a continuous sum of sine-Gordon type interactions
Bethe ansatz approach to quantum sine Gordon thermodynamics and finite temperature excitations
International Nuclear Information System (INIS)
Zotos, X.
1982-01-01
Takahashi and Suzuki (TS) using the Bethe ansatz method developed a formalism for the thermodynamics of the XYZ spin chain. Translating their formalism to the quantum sine-Gordon system, the thermodynamics and finite temperature elementary excitations are analyzed. Criteria imposed by TS on the allowed states simply correspond to the condition of normalizability of the wave functions. A set of coupled nonlinear integral equations for the thermodynamic equilibrium densities for particular values of the coupling constant in the attractive regime is derived. Solving numerically these Bethe ansatz equations, curves of the specific heat as a function of temperature are obtained. The soliton contribution peaks at a temperature of about 0.4 soliton masses shifting downward as the classical limit is approached. The weak coupling regime is analyzed by deriving the Bethe ansatz equations including the charged vacuum excitations. It is shown that they are necessary for a consistent presentation of the thermodynamics
Stochastically-driven coherence in a sine-Gordon chain
International Nuclear Information System (INIS)
Guerrero, L.E.; Hasmy, A.; Mata, G.J.
1994-01-01
We perform numerical simulations of the dynamical behavior of a sine-Gordon chain in a heat bath. The interaction with the heat bath is simulated by the Langevin formalism. The noise term is uncorrelated in both space and time. We use the Karhunen-Loeve decomposition to study the effective number of degrees of freedom as a function of temperature (i.e., of the noise dispersion). At low temperatures we find a spatially disordered regime, characterized by a high number of degrees of freedom. At a temperature of the order of the soliton rest mass we find a relatively sharp crossover to an ordered regime, characterized by a low number of degrees of freedom. The spatial structure of the modes suggests that the transition is associated to the appearance of thermally activated solitons. We also present an alternative estimate of the effective number of degrees of freedom. (orig.)
Scattering of sine-Gordon kinks on potential wells
International Nuclear Information System (INIS)
Piette, Bernard; Zakrzewski, W J
2007-01-01
We study the scattering properties of sine-Gordon kinks on obstructions in the form of finite size potential 'wells'. We model this by making the coefficient of the cos(ψ) - 1 term in the Lagrangian position dependent. We show that when the kinks find themselves in the well they radiate and then interact with this radiation. As a result of this energy loss, the kinks become trapped for small velocities while at higher velocities they are transmitted with a loss of energy. However, the interaction with the radiation can produce 'unexpected' reflections by the well. We present two simple models which capture the gross features of this behaviour. Both involve standing waves either at the edges of the well or in the well itself
Quantum aspects of the noncommutative Sine-Gordon model
International Nuclear Information System (INIS)
Kuerkcueoglu
2007-01-01
In this talk, I will first present some of the quantum field theoretical aspects of the integrable noncommutative sine-Gordon model proposed in [hep-th/0406065] using standard semi-classical methods. In particular, I will discuss the fluctuations at quadratic order around the static kink solution using the background field method. I will argue that at 0(θ 2 ) the spectrum of fluctuations remains essentially the same as that of the corresponding commutative theory. A brief analysis of one-loop two-point functions will also be presented and it will be followed by some remarks on the obstacles in determining the noncommutativity corrections to the quantum mass of the kink. (author)
Scattering of the double sine-Gordon kinks
Gani, Vakhid A.; Marjaneh, Aliakbar Moradi; Askari, Alidad; Belendryasova, Ekaterina; Saadatmand, Danial
2018-04-01
We study the scattering of kink and antikink of the double sine-Gordon model. There is a critical value of the initial velocity v_{{cr}} of the colliding kinks, which separates different regimes of the collision. At v_{in}>v_{cr} we observe kinks reflection, while at v_{in}
Noether's theorem and Steudel's conserved currents for the sine-Gordon equation
International Nuclear Information System (INIS)
Shadwick, W.F.
1980-01-01
A version of Noether's theorem appropriate for the extended Hamilton-Cartan formalism for regular first-order Lagrangians is proposed. Steudel's derivation of an infinite collection of conserved currents for the sine-Gordon equation is presented in this context and it is demonstrated that, as a consequence of the commutativity of the sine-Gordon Baecklund transformations, the conserved charges corresponding to these currents are in involution with respect to the natural Poisson bracket provided by the formalism. Thus one obtains the formal 'complete integrability' of the sine-Gordon equation as a consequence of the properties of the Baecklund transformation. (orig.)
Generating Solutions to Discrete sine-Gordon Equation from Modified Baecklund Transformation
International Nuclear Information System (INIS)
Kou Xin; Zhang Dajun; Shi Ying; Zhao Songlin
2011-01-01
We modify the bilinear Baecklund transformation for the discrete sine-Gordon equation and derive variety, of solutions by freely choosing parameters from the modified Baecklund transformation. Dynamics of solutions and continuum limits are also discussed. (general)
International Nuclear Information System (INIS)
Davidson, A.; Pedersen, N.F.; Dueholm, B.
1985-01-01
We show some experimental results which suggest that total damping, including surface loss, plays a fundamental role in limiting the stability of high-velocity Sine-Gordon solitons in real Josephson tunnel junctions
Rotationally symmetric breather-like solutions to the sine-Gordon equation
International Nuclear Information System (INIS)
Olsen, O.H.; Samuelsen, M.R.
1980-01-01
Breather-like solutions to the spherically symmetric sine-Gordon equation are examined numerically. Depending on the initial conditions they either exhibit a return effect or expand towards infinity. (orig.)
Pi-kinks in a parametrically driven sine-Gordon chain
DEFF Research Database (Denmark)
Kivshar, Yuri S.; Grønbech-Jensen, Niels; Samuelsen, Mogens Rugholm
1992-01-01
We consider the sine-Gordon chain driven by a high-frequency parametric force in the presence of loss. Using an analytical approach based on the method of averaging in fast oscillations, we predict that such a parametric force may support propagation of π kinks, which are unstable in the standard...... sine-Gordon model. The steady-state velocity of the π kinks is calculated, and the analytical results are in good agreement with direct numerical simulations....
Critical values of the Yang-Yang functional in the quantum sine-Gordon model
International Nuclear Information System (INIS)
Lukyanov, Sergei L.
2011-01-01
The critical values of the Yang-Yang functional corresponding to the vacuum states of the sine-Gordon QFT in the finite-volume are studied. Two major applications are discussed: (i) generalization of Fendley-Saleur-Zamolodchikov relations to arbitrary values of the sine-Gordon coupling constant, and (ii) connection problem for a certain two-parameter family of solutions of the Painleve III equation.
DEFF Research Database (Denmark)
Davidson, A.; Pedersen, Niels Falsig; Dueholm, B.
1985-01-01
We show some experimental results which suggest that total damping, including surface loss, plays a fundamental role in limiting the stability of high-velocity sine-Gordon solitons in real Josephson tunnel junctions.......We show some experimental results which suggest that total damping, including surface loss, plays a fundamental role in limiting the stability of high-velocity sine-Gordon solitons in real Josephson tunnel junctions....
Quantum conserved charges in N=1 and N=2 supersymmetric sine-Gordon theories
International Nuclear Information System (INIS)
Kobayashi, Ken-ichiro; Uematsu, Tsuneo; Yu Yangzheng
1993-01-01
We investigate quantum conservation laws in the N=1 and N=2 supersymmetric sine-Gordon theories. We study conserved charges at the quantum level based on perturbation theory formulated in superspace. It will turn out that there exist extra conserved charges of the vertex operator type at the quantum level and they generate a quantum group symmetry in supersymmetric sine-Gordon systems. We also discuss the implication of the quantum group symmetry on the S-matrix structure. (orig.)
Exact expectation values of local fields in the quantum sine-Gordon model
International Nuclear Information System (INIS)
Lukyanov, S.; Rossijskaya Akademiya Nauk, Chernogolovka; Zamolodchikov, A.; Rossijskaya Akademiya Nauk, Chernogolovka
1997-01-01
We propose an explicit expression for vacuum expectation values left angle e iaφ right angle of the exponential fields in the sine-Gordon model. Our expression agrees both with semi-classical results in the sine-Gordon theory and with perturbative calculations in the massive Thirring model. We use this expression to make new predictions about the large-distance asymptotic form of the two-point correlation function in the XXZ spin chain. (orig.)
Critical behavior and duality in extended Sine-Gordon theories
International Nuclear Information System (INIS)
Boyanovsky, D.; Holman, R.
1991-01-01
We study the critical properties of vectorial sine-Gordon theories based on the root system of simply-laced Lie algebras. We introduce the dual operators and study the renormalization aspects of these theories. These models are identified with vectorial Coulomb gas models of electric and magnetic charges and generalized Toda field theories. We prove that these theories are consistently renormalizable for simply-laced Lie algebras, but non-renormalizable in general in the non-simply-laced case. These models provide a description for the statistical mechanics of melting in the SU(3) case. They also provide a simplified model for strings compactified on root lattices. We compute the RG beta functions to quadratic order for general simply-laced algebras and find that in general there is a Weyl singlet, self-dual fixed point. This fixed point describes a critical theory with condensates of electric and magnetic charges corresponding to tachyonic and winding modes in string language. The different phases are related by Weyl and duality symmetry. The phase structure is conjectured in the general case, and analyzed in detail for SU(3) and SO(6). We compute Zamolodchikov's c-function to cubic order in the couplings in the general case and the conformal anomaly at the self-dual fixed point for SU(N). (orig.)
International Nuclear Information System (INIS)
Kovalyov, Mikhail
2010-01-01
In this article the sets of solutions of the sine-Gordon equation and its linearization the Klein-Gordon equation are discussed and compared. It is shown that the set of solutions of the sine-Gordon equation possesses a richer structure which partly disappears during linearization. Just like the solutions of the Klein-Gordon equation satisfy the linear superposition principle, the solutions of the sine-Gordon equation satisfy a nonlinear superposition principle.
Heun equation in a 5D sine-Gordon brane-world model with dilaton
International Nuclear Information System (INIS)
Cunha, M.S.; Christiansen, H.
2011-01-01
Full text: In a brane-world scenario we find the propagation modes of the gauge field in a five-dimensional space-time. We adopt warping factors of the Randall-Sundrum type which are appropriate to regularize the hierarchy problem without imposing finite compactified extra dimensions. The existence and localization of gauge particles in the ordinary four-dimensional world is studied in detail on a thick brane derived out from the equations of motion of an action with a sine-Gordon potential contribution. Maxwell zero modes together with torsion effective fields are then obtained in a gravity-dilaton background inspired in close string theories. The dilaton plays a crucial role in order that the gauge field gets localized in a conformally invariant context. Kaluza-Klein massive states are also computed and, depending on certain parameters like dilaton coupling constant and asymptotic curvature, we are able to do it fully analytically. In a general approach we find that the solutions are of the Heun type. In some specific cases we can show that the Heun general solutions can be transformed into hypergeometric functions. In others, confluent Heun solutions can be transformed into simpler functions like Mathieu functions. Exact mass spectra are found in several cases. In others, we performed numerical calculations that show a well behaved phenomenology as well. In all the cases, Kaluza-Klein modes are strongly suppressed on the brane in the effective four-dimensional theory. (author)
Kink-antikink interactions in a modified sine-Gordon model
International Nuclear Information System (INIS)
Peyrard, M.; Campbell, D.K.; Los Alamos National Lab., NM
1983-01-01
We study numerically the interactions of a kink (K) and an antikink (anti K) in a parametrically modified sine-Gordon model with potential V(PHI)=(1-r) 2 (1-cos PHI)/(1+r 2 +2r cos PHI). As the parameter r is varied from the pure sine-Gordon case (r=0) to values for which the model is not completely integrable (rnot=0), we find that a rich structure arises in the Kanti K collisions. For some regions of r(-0.20 4 model, and we show that the theory recently suggested for these collisions also applies quantitatively to the modified sine-Gordon model. In other regions of r we observe new scattering phenomena, which we present in detail numerically and discuss in a qualitative manner analytically. (orig.)
The sine-Gordon model and the small κ+ region of light- cone perturbation theory
International Nuclear Information System (INIS)
Griffin, P.A.
1992-01-01
The non-perturbative ultraviolet divergence of the sine-Gordon model is used to study the k + = 0 region of light-cone perturbation theory. The light-cone vacuum is shown to be unstable at the non- perturbative β 2 = 8π critical point by a light-cone version of Coleman's variational method. Vacuum bubbles, which are k + = 0 diagram in light-cone field theory and are individually finite and non-vanishing for all β, conspire to generate ultraviolet divergences of the light-cone energy density. The k + = 0 region of momentum also contributed to connected Green's functions: the connected two point function will not diverge, as it should, at the critical point unless diagrams which contribute only at k + = 0 are properly included. This analysis shows in a simple way how the k + = 0 region cannot be ignored even for connected diagrams. This phenomenon is expected to occur in higher dimensional gauge theories starting at two loop order in light-cone perturbation theory
International Nuclear Information System (INIS)
Baron, H.E.; Zakrzewski, W.J.
2016-01-01
We investigate the validity of collective coordinate approximations to the scattering of two solitons in several classes of (1+1) dimensional field theory models. We consider models which are deformations of the sine-Gordon (SG) or the nonlinear Schrödinger (NLS) model which posses soliton solutions (which are topological (SG) or non-topological (NLS)). Our deformations preserve their topology (SG), but change their integrability properties, either completely or partially (models become ‘quasi-integrable’). As the collective coordinate approximation does not allow for the radiation of energy out of a system we look, in some detail, at how the approximation fares in models which are ‘quasi-integrable’ and therefore have asymptotically conserved charges (i.e. charges Q(t) for which Q(t→−∞)=Q(t→∞)). We find that our collective coordinate approximation, based on geodesic motion etc, works amazingly well in all cases where it is expected to work. This is true for the physical properties of the solitons and even for their quasi-conserved (or not) charges. The only time the approximation is not very reliable (and even then the qualitative features are reasonable, but some details are not reproduced well) involves the processes when the solitons come very close together (within one width of each other) during their scattering.
International Nuclear Information System (INIS)
Nandori, I.; Jentschura, U.D.; Soff, G.; Sailer, K.
2004-01-01
Renormalization-group (RG) flow equations have been derived for the generalized sine-Gordon model (GSGM) and the Coulomb gas (CG) in d≥3 of dimensions by means of the Wegner-Houghton method, and by way of the real-space RG approach. The UV scaling laws determined by the leading-order terms of the flow equations are in qualitative agreement for all dimensions d≥3, independent of the dimensionality, and in sharp contrast to the special case d=2. For the 4-dimensional GSGM it is demonstrated explicitly (by numerical calculations) that the blocked potential tends to a constant effective potential in the infrared limit, satisfying the requirements of periodicity and convexity. The comparison of the RG flows for the three-dimensional GSGM, the CG, and the vortex-loop gas reveals a significant dependence on the renormalization schemes and the approximations used
International Nuclear Information System (INIS)
Itoyama, H.; Korepin, V.E.; Thacker, H.B.
1992-01-01
In this paper, correlation functions of the Sine-Gordon model (which is equivalent of the Massive-Thirring model) are considered at the free fermion point. The authors derive a determinant formula for local correlation functions of the Sine-Gordon model, starting form Bethe ansatz wave function. Kernel of integral operator is trigonometric version of the one for Impenetrable Bosons
Arbitrarily large numbers of kink internal modes in inhomogeneous sine-Gordon equations
Energy Technology Data Exchange (ETDEWEB)
González, J.A., E-mail: jalbertgonz@yahoo.es [Department of Physics, Florida International University, Miami, FL 33199 (United States); Department of Natural Sciences, Miami Dade College, 627 SW 27th Ave., Miami, FL 33135 (United States); Bellorín, A., E-mail: alberto.bellorin@ucv.ve [Escuela de Física, Facultad de Ciencias, Universidad Central de Venezuela, Apartado Postal 47586, Caracas 1041-A (Venezuela, Bolivarian Republic of); García-Ñustes, M.A., E-mail: monica.garcia@pucv.cl [Instituto de Física, Pontificia Universidad Católica de Valparaíso, Casilla 4059 (Chile); Guerrero, L.E., E-mail: lguerre@usb.ve [Departamento de Física, Universidad Simón Bolívar, Apartado Postal 89000, Caracas 1080-A (Venezuela, Bolivarian Republic of); Jiménez, S., E-mail: s.jimenez@upm.es [Departamento de Matemática Aplicada a las TT.II., E.T.S.I. Telecomunicación, Universidad Politécnica de Madrid, 28040-Madrid (Spain); Vázquez, L., E-mail: lvazquez@fdi.ucm.es [Departamento de Matemática Aplicada, Facultad de Informática, Universidad Complutense de Madrid, 28040-Madrid (Spain)
2017-06-28
We prove analytically the existence of an infinite number of internal (shape) modes of sine-Gordon solitons in the presence of some inhomogeneous long-range forces, provided some conditions are satisfied. - Highlights: • We have found exact kink solutions to the perturbed sine-Gordon equation. • We have been able to study analytically the kink stability problem. • A kink equilibrated by an exponentially-localized perturbation has a finite number of oscillation modes. • A sufficiently broad equilibrating perturbation supports an infinite number of soliton internal modes.
Intermittent Switching between Soliton Dynamic States in a Perturbed Sine-Gordon Model
DEFF Research Database (Denmark)
Sørensen, Mads Peter; Arley, N.; Christiansen, Peter Leth
1983-01-01
Chaotic intermittency between soliton dynamic states has been found in a perturbed sine-Gordon system in the absence of an external ac driving term. The system is a model of a long Josephson oscillator with constant loss and bias current in an external magnetic field. The results predict the exis......Chaotic intermittency between soliton dynamic states has been found in a perturbed sine-Gordon system in the absence of an external ac driving term. The system is a model of a long Josephson oscillator with constant loss and bias current in an external magnetic field. The results predict...
Thermal sine-Gordon system in the presence of different types of dissipation
DEFF Research Database (Denmark)
Salerno, M.; Samuelsen, Mogens Rugholm; Svensmark, Henrik
1988-01-01
The effects of thermal fluctuations on solitons and phonons of the sine-Gordon system are investigated in the presence of a αφt-βφxxt dissipation. The analysis requires the assumption of a more general autocorrelation function for the noise than the one used in previous works. We verify that this......The effects of thermal fluctuations on solitons and phonons of the sine-Gordon system are investigated in the presence of a αφt-βφxxt dissipation. The analysis requires the assumption of a more general autocorrelation function for the noise than the one used in previous works. We verify...
Covariant form for the conserved currents of the sine-Gordon and Liouville theories
International Nuclear Information System (INIS)
Freedman, D.Z.; Massachusetts Inst. of Tech., Cambridge; Lerda, A.; Massachusetts Inst. of Tech., Cambridge; Penati, S.
1990-01-01
A conserved covariant fourth rank tensor current J μαβγ is constructed for these models both in flat and constant curvature space. For flat space, ∫ dx + J ++++ and its parity conjugate agree with well known results for the lowest grade sine-Gordon conserved charges. However potentially new charges such as ∫ dx + J +++- and ∫ dx + J +++α ε αβ x β either vanish or fail to be conserved because J μαβγ is not symmetric in μ↔γ. There is one curious exception for sine-Gordon models in anti-de Sitter space. (orig.)
Reshaping-induced spatiotemporal chaos in driven, damped sine-Gordon systems
International Nuclear Information System (INIS)
Chacon, R.
2007-01-01
Spatiotemporal chaos arising from the competition between sine-Gordon-breather and kink-antikink-pair solitons by reshaping an ac force is demonstrated. After introducing soliton collective coordinates, Melnikov's method is applied to the resulting effective equation of motion to estimate the parameter-space regions of the ac force where homoclinic bifurcations are induced. The analysis reveals that the chaos-order threshold exhibits sensitivity to small changes in the force shape. Computer simulations of the sine-Gordon system show good agreement with these theoretical predictions
Reshaping-induced spatiotemporal chaos in driven, damped sine-Gordon systems
Energy Technology Data Exchange (ETDEWEB)
Chacon, R. [Departamento de Electronica e Ingenieria Electromecanica, Escuela de Ingenierias Industriales, Universidad de Extremadura, E-06071 Badajoz (Spain)]. E-mail: rchacon@unex.es
2007-03-15
Spatiotemporal chaos arising from the competition between sine-Gordon-breather and kink-antikink-pair solitons by reshaping an ac force is demonstrated. After introducing soliton collective coordinates, Melnikov's method is applied to the resulting effective equation of motion to estimate the parameter-space regions of the ac force where homoclinic bifurcations are induced. The analysis reveals that the chaos-order threshold exhibits sensitivity to small changes in the force shape. Computer simulations of the sine-Gordon system show good agreement with these theoretical predictions.
International Nuclear Information System (INIS)
Nandori, I; Jentschura, U D; Nagy, S; Sailer, K; Vad, K; Meszaros, S
2007-01-01
We find a mapping of the layered sine-Gordon model to an equivalent gas of topological excitations and determine the long-range interaction potentials of the topological defects. This enables us to make a detailed comparison to the so-called layered vortex gas, which can be obtained from the layered Ginzburg-Landau model. The layered sine-Gordon model has been proposed in the literature as a candidate field-theoretical model for Josephson-coupled high-T c superconductors, and the implications of our analysis for the applicability of the layered sine-Gordon model to high-T c superconductors are discussed. We are led to the conjecture that the layered sine-Gordon and the layered vortex gas models belong to different universality classes. The determination of the critical temperature of the layered sine-Gordon model is based on a renormalization-group analysis
Breather kink-antikink-pair conversion in the driven sine-Gordon system
DEFF Research Database (Denmark)
Lomdahl, P. S.; Olsen, O. H.; Samuelsen, Mogens Rugholm
1984-01-01
Breather excitations in the sine-Gordon equation influenced by constant driving forces are investigated—large driving forces cause the breather to split into a kk― (2π kink-2π antikink) pair while for small driving forces the breather excitations enter stationary modes. A perturbation method...
Internal oscillation frequencies and anharmonic effects for the double sine-Gordon kink
DEFF Research Database (Denmark)
Salerno, M.; Samuelsen, Mogens Rugholm
1989-01-01
A simple derivation of the small oscillation frequency around 4π-kink solutions of the double sine-Gordon equation is presented. Small corrections to these frequencies due to anharmonic effects are also numerically and analytically investigated. The analysis is based on energetic considerations...
Stabilization of breathers in a parametrically driven sine-Gordon system with loss
DEFF Research Database (Denmark)
Grønbech-Jensen, N.; Kivshar, Yu. S.; Samuelsen, Mogens Rugholm
1991-01-01
We demonstrate that in a parametrically driven sine-Gordon system with loss, a breather, if driven, can be maintained in a steady state at half the external frequency. In the small-amplitude limit the system is described by the effective perturbed nonlinear Schrödinger equation. For an arbitrary...
Scattering of topological solitons on barriers and holes of deformed Sine-Gordon models
International Nuclear Information System (INIS)
Al-Alawi, Jassem H; Zakrzewski, Wojtek J
2008-01-01
We study various scattering properties of topological solitons in two classes of models, which are the generalizations of the Sine-Gordon model and which have recently been proposed by Bazeia et al. These two classes of models depend on a positive real nonzero parameter n but in this paper we consider the models only for its integer values as when n = 2 (for the first class) and n = 1 (for the second class), the model reduces to the Sine-Gordon one. We take the soliton solutions of these models (generalizations of the 'kink' solution of the Sine-Gordon model) and consider their scattering on potential holes and barriers. We present our results for n = 1, ..., 6. We find that, like in the Sine-Gordon models, the scattering on the barrier is very elastic while the scattering on the hole is inelastic and can, at times, lead to a reflection. We discuss the dependence of our results on n and find that the critical velocity for the transmission through the hole is lowest for n = 3
Grand partition function in field theory with applications to sine-Gordon field theory
International Nuclear Information System (INIS)
Samuel, S.
1978-01-01
Certain relativistic field theories are shown to be equivalent to the grand partition function of an interacting gas. Using the physical insight given by this analogy many field-theoretic results are obtained, particularly for the sine-Gordon field theory. The main results are enumerated in the summary to which the reader is referred
Solitons and separable elliptic solutions of the sine-Gordon equation
International Nuclear Information System (INIS)
Bryan, A.C.; Haines, C.R.; Stuart, A.E.G.
1979-01-01
It is pointed out that the two-soliton (antisoliton) solutions of the sine-Gordon equation may be obtained as limiting cases of a separable, two-parameter family of elliptic solutions. The solitons are found on the boundary of the parameter space for the elliptic solutions when the latter are considered over their usual complex domain. (Auth.)
Simple connection between conservation laws in the Korteweg--de Vriesand sine-Gordon systems
International Nuclear Information System (INIS)
Chodos, A.
1980-01-01
An infinite sequence of conserved quantities follows from the Lax representation in both the Korteweg--de Vries and sine-Gordon systems. We show that these two sequences are related by a simple substitution. In an appendix, two different methods of deriving conservation laws from the Lax representation are presented
Persistent breather excitations in an ac-driven sine-Gordon system with loss
International Nuclear Information System (INIS)
Lomdahl, P.S.; Samuelsen, M.R.
1986-01-01
In a sine-Gordon system with loss and applied ac driver, a breather can be maintained as a persistent entrained oscillation if the driver is strong enough. The threshold field is determined by a perturbation method and compared to numerical experiments. Excellent agreement is found
Sine-Gordon 2-pi-kink dynamics in the presence of small perturbations
DEFF Research Database (Denmark)
Olsen, O. H.; Samuelsen, Mogens Rugholm
1983-01-01
The influence of external driving forces on the 2π-kink solution to the sine-Gordon equation is examined. The analysis is based on the approach that the solution to the problem can be divided into a 2π-kink part and a background or vacuum part. The behavior of the 2π kink depends strongly...
An equivalence between the discrete Gaussian model and a generalized Sine Gordon theory on a lattice
International Nuclear Information System (INIS)
Baskaran, G.; Gupte, N.
1983-11-01
We demonstrate an equivalence between the statistical mechanics of the discrete Gaussian model and a generalized Sine-Gordon theory on an Euclidean lattice in arbitrary dimensions. The connection is obtained by a simple transformation of the partition function and is non perturbative in nature. (author)
Sabirov, K.; Rakhmanov, S.; Matrasulov, D.; Susanto, H.
2018-04-01
We consider the stationary sine-Gordon equation on metric graphs with simple topologies. Exact analytical solutions are obtained for different vertex boundary conditions. It is shown that the method can be extended for tree and other simple graph topologies. Applications of the obtained results to branched planar Josephson junctions and Josephson junctions with tricrystal boundaries are discussed.
Approximate treatment of two soliton solutions of the sine-Gordon equation
International Nuclear Information System (INIS)
Mihaly, L.
1979-05-01
The so called breather solution of the sine-Gordon equation is phenomenologically described by an appropri.ately choosen potential acting between two particles. For some applications the method proves to be equivalent to other classical and quantum calculations. (author)
Sine-Gordon equation as a model of a nonlinear scalar field in the Duffin-Kemmer formalism
International Nuclear Information System (INIS)
Getmanov, B.S.
1980-01-01
The nonlinear self-interaction of a scalar field is studied in the Minkowski space-time of an arbitrary dimension. It is shown that the sine-Gordon equation can be considered as a model of the nonlinear scalar field in the Duffin-Kemmer formalism with a specific kind of nonlinearity. The ''V-A'' type interaction is found to be equivalent to the ''complex sine-Gordon'' model. Such a new formation of the sine-Gordon equation might be useful for search for its integrable generalizations
NLIE of Dirichlet sine-Gordon model for boundary bound states
International Nuclear Information System (INIS)
Ahn, Changrim; Bajnok, Zoltan; Palla, Laszlo; Ravanini, Francesco
2008-01-01
We investigate boundary bound states of sine-Gordon model on the finite-size strip with Dirichlet boundary conditions. For the purpose we derive the nonlinear integral equation (NLIE) for the boundary excited states from the Bethe ansatz equation of the inhomogeneous XXZ spin 1/2 chain with boundary imaginary roots discovered by Saleur and Skorik. Taking a large volume (IR) limit we calculate boundary energies, boundary reflection factors and boundary Luescher corrections and compare with the excited boundary states of the Dirichlet sine-Gordon model first considered by Dorey and Mattsson. We also consider the short distance limit and relate the IR scattering data with that of the UV conformal field theory
TBA equations for excited states in the sine-Gordon model
International Nuclear Information System (INIS)
Balog, Janos; Hegedus, Arpad
2004-01-01
We propose thermodynamic Bethe ansatz (TBA) integral equations for multi-particle soliton (fermion) states in the sine-Gordon (massive Thirring) model. This is based on T-system and Y-system equations, which follow from the Bethe ansatz solution in the light-cone lattice formulation of the model. Even and odd charge sectors are treated on an equal footing, corresponding to periodic and twisted boundary conditions, respectively. The analytic properties of the Y-system functions are conjectured on the basis of the large volume solution of the system, which we find explicitly. A simple relation between the TBA Y-functions and the counting function variable of the alternative non-linear integral equation (Destri-de Vega equation) description of the model is given. At the special value β 2 = 6π of the sine-Gordon coupling, exact expressions for energy and momentum eigenvalues of one-particle states are found
International Nuclear Information System (INIS)
Yan Zhenya
2005-01-01
A new transformation method is developed using the general sine-Gordon travelling wave reduction equation and a generalized transformation. With the aid of symbolic computation, this method can be used to seek more types of solutions of nonlinear differential equations, which include not only the known solutions derived by some known methods but new solutions. Here we choose the double sine-Gordon equation, the Magma equation and the generalized Pochhammer-Chree (PC) equation to illustrate the method. As a result, many types of new doubly periodic solutions are obtained. Moreover when using the method to these special nonlinear differential equations, some transformations are firstly needed. The method can be also extended to other nonlinear differential equations
Nonlinear Fourier transforms for the sine-Gordon equation in the quarter plane
Huang, Lin; Lenells, Jonatan
2018-03-01
Using the Unified Transform, also known as the Fokas method, the solution of the sine-Gordon equation in the quarter plane can be expressed in terms of the solution of a matrix Riemann-Hilbert problem whose definition involves four spectral functions a , b , A , B. The functions a (k) and b (k) are defined via a nonlinear Fourier transform of the initial data, whereas A (k) and B (k) are defined via a nonlinear Fourier transform of the boundary values. In this paper, we provide an extensive study of these nonlinear Fourier transforms and the associated eigenfunctions under weak regularity and decay assumptions on the initial and boundary values. The results can be used to determine the long-time asymptotics of the sine-Gordon quarter-plane solution via nonlinear steepest descent techniques.
Coherence and chaos in the driven damped sine-Gordon equation: Measurement of the soliton spectrum
Energy Technology Data Exchange (ETDEWEB)
Overman, II, E A; McLaughlin, D W; Bishop, A R; Los Alamos National Lab., NM
1986-02-01
A numerical procedure is developed which measures the sine-Gordon soliton and radiation content of any field (PHI, PHIsub(t)) which is periodic in space. The procedure is applied to the field generated by a damped, driven sine-Gordon equation. This field can be either temporally periodic (locked to the driver) or chaotic. In either case the numerical measurement shows that the spatial structure can be described by only a few spatially localized (soliton wave-train) modes. The numerical procedure quantitatively identifies the presence, number and properties of these soliton wave-trains. For example, an increase of spatial symmetry is accompanied by the injection of additional solitons into the field. (orig.).
Exact Travelling Solutions of Discrete sine-Gordon Equation via Extended Tanh-Function Approach
International Nuclear Information System (INIS)
Dai Chaoqing; Zhang Jiefang
2006-01-01
In this paper, we generalize the extended tanh-function approach, which was used to find new exact travelling wave solutions of nonlinear partial differential equations or coupled nonlinear partial differential equations, to nonlinear differential-difference equations. As illustration, two series of exact travelling wave solutions of the discrete sine-Gordon equation are obtained by means of the extended tanh-function approach.
An Implicit Scheme of Lattice Boltzmann Method for Sine-Gordon Equation
International Nuclear Information System (INIS)
Hui-Lin, Lai; Chang-Feng, Ma
2008-01-01
We establish an implicit scheme of lattice Boltzmann method for simulating the sine-Gordon equation, which can be transformed into the explicit one, so the computation of the scheme is simple. Moreover, the parameter θ of the implicit scheme is independent of the relaxation time, which makes the model more flexible. The numerical results show that this method is very effective. (fundamental areas of phenomenology (including applications))
Instanton contributions to the valence band of the double Sine-Gordon potential
International Nuclear Information System (INIS)
Ricotta, R.M.; Escobar, C.O.
1982-01-01
The energy dispersion relation for the valence band of the double sine-Gordon potential is calculated, approximating the tunneling amplitude by a sum of contributions of multi-instantons and anti-instatons trajectories. The interesting feature of this potential is that they have to deal with two types of instantons, as there are two different potential barriers within one period of the potential. The results with the standard WKB approximation are compared. (Author) [pt
On a Kubo-Martin-Schwinger state of the Sine-Gordon system
International Nuclear Information System (INIS)
Peskov, N.V.
1986-01-01
This paper considers the Sine-Gordon equation on a finite interval as a Hamiltonian system. A Gaussian measure is defined on an extension of the phase space. It is shown that the partition funciton Z employed in the statistical mechanics of the solitons is an integral with respect to this measure. An algebra of observables is defined and on it a state is constructed which satisfies the Kubo-Martin-Schwinger condition
International Nuclear Information System (INIS)
Garbaczewski, P.
1982-01-01
Previously we have found that the semiclassical sine--Gordon/Thirring spectrum can be received in the absence of quantum solitons via the spin 1/2 approximation of the quantized sine--Gordon system on a lattice. Later on, we have recovered the Hilbert space of quantum soliton states for the sine--Gordon system. In the present paper we present a derivation of the Bethe Ansatz eigenstates for the generalized ice model in this soliton Hilbert space. We demonstrate that via ''Wick rotation'' of a fundamental parameter of the ice model one arrives at the Bethe Ansatz eigenstates of the quantum sine--Gordon system. The latter is a ''local transition matrix'' ancestor of the coventional sine--Gordon/Thirring model, as derived by Faddeev et al. within the quantum inverse-scattering method. Our result is essentially based on the N< infinity,Δ = 1,m<<1 regime. Consequently, the spectrum received, though resembling the semiclassical one, does not coincide with it at all
Post-Gaussian Effective Potential of Double sine-Gordon Field
International Nuclear Information System (INIS)
Cai Weiran; Lou Senyue
2005-01-01
In the framework of the functional integral formalism, we calculate the effective potential of the double sine-Gordon (DsG) model up to the second order with an optimized expansion and the Coleman's normal-ordering prescription. Within the range of convergence, we make a comparison among the classical and the effective potential of the first and second order. The numerical analysis shows that the DsG post-Gaussian EP possesses some fine global properties and makes a substantial and a concordant quantum correction to the features of the classical potential.
Exact Mass-Coupling Relation for the Homogeneous Sine-Gordon Model.
Bajnok, Zoltán; Balog, János; Ito, Katsushi; Satoh, Yuji; Tóth, Gábor Zsolt
2016-05-06
We derive the exact mass-coupling relation of the simplest multiscale quantum integrable model, i.e., the homogeneous sine-Gordon model with two mass scales. The relation is obtained by comparing the perturbed conformal field theory description of the model valid at short distances to the large distance bootstrap description based on the model's integrability. In particular, we find a differential equation for the relation by constructing conserved tensor currents, which satisfy a generalization of the Θ sum rule Ward identity. The mass-coupling relation is written in terms of hypergeometric functions.
A note on a boundary sine-Gordon model at the free-Fermion point
Murgan, Rajan
2018-02-01
We investigate the free-Fermion point of a boundary sine-Gordon model with nondiagonal boundary interactions for the ground state using auxiliary functions obtained from T - Q equations of a corresponding inhomogeneous open spin-\\frac{1}{2} XXZ chain with nondiagonal boundary terms. In particular, we obtain the Casimir energy. Our result for the Casimir energy is shown to agree with the result from the TBA approach. The analytical result for the effective central charge in the ultraviolet (UV) limit is also verified from the plots of effective central charge for intermediate values of volume.
International Nuclear Information System (INIS)
Fogel, M.B.; Trullinger, S.E.; Bishop, A.R.; Krumhansl, J.A.
1976-02-01
We show that classical Sine-Gordon solitons maintain their integrity to a high degree in the presence of external perturbations. Two examples, of particular importance in condensed matter, are described in detail: (i) a model impurity is found to bind low-velocity solitons but merely phase-shift those with high-velocities, (ii) external static driving terms with damping accelerate the soliton to a terminal velocity. The importance of a translation mode is emphasized and it is concluded that the soliton behaves as a classical particle in all essential respects
Numerical simulation of the self-pumped long Josephson junction using a modified sine-Gordon model
International Nuclear Information System (INIS)
Sobolev, A.S.; Pankratov, A.L.; Mygind, J.
2006-01-01
We have numerically investigated the dynamics of a long Josephson junction (flux-flow oscillator) biased by a DC current in the presence of magnetic field. The study is performed in the frame of the modified sine-Gordon model, which includes the surface losses, RC-load at both FFO ends and the self-pumping effect. In our model the dumping parameter depends both on the spatial coordinate and the amplitude of the AC voltage. In order to find the DC FFO voltage the damping parameter has to be calculated by successive approximations and time integration of the perturbed sine-Gordon equation. The modified model, which accounts for the presence of the superconducting gap, gives better qualitative agreement with experimental results compare to the conventional sine-Gordon model
Numerical simulation of the self-pumped long Josephson junction using a modified sine-Gordon model
DEFF Research Database (Denmark)
Sobolev, A.; Pankratov, A.; Mygind, Jesper
2006-01-01
We have numerically investigated the dynamics of a long Josephson junction (flux-flow oscillator) biased by a DC current in the presence of magnetic field. The study is performed in the frame of the modified sine-Gordon model, which includes the surface losses, RC-load at both FFO ends and the self-pumping...... effect. In our model the dumping parameter depends both on the spatial coordinate and the amplitude of the AC voltage. In order to find the DC FFO voltage the damping parameter has to be calculated by successive approximations and time integration of the perturbed sine-Gordon equation. The modified model...
Sine-Gordon equation and its application to tectonic stress transfer
Bykov, Victor G.
2014-07-01
An overview is given on remarkable progress that has been made in theoretical studies of solitons and other nonlinear wave patterns, excited during the deformation of fault block (fragmented) geological media. The models that are compliant with the classical and perturbed sine-Gordon equations have only been chosen. In these mathematical models, the rotation angle of blocks (fragments) and their translatory displacement of the medium are used as dynamic variables. A brief description of the known models and their geophysical and geodynamic applications is given. These models reproduce the kinematic and dynamic features of the traveling deformation front (kink, soliton) generated in the fragmented media. It is demonstrated that the sine-Gordon equation is applicable to the description of series of the observed seismic data, modeling of strain waves, as well as the features related to fault dynamics and the subduction slab, including slow earthquakes, periodicity of episodic tremor and slow slip (ETS) events, and migration pattern of tremors. The study shows that simple heuristic models and analytical and numerical computations can explain triggering of seismicity by transient processes, such as stress changes associated with solitary strain waves in crustal faults. The need to develop the above-mentioned new (nonlinear) mathematical models of the deformed fault and fragmented media was caused by the reason that it is impossible to explain a lot of the observed effects, particularly, slow redistribution and migration of stresses in the lithosphere, within the framework of the linear elasticity theory.
Quench dynamics near a quantum critical point: Application to the sine-Gordon model
International Nuclear Information System (INIS)
De Grandi, C.; Polkovnikov, A.; Gritsev, V.
2010-01-01
We discuss the quench dynamics near a quantum critical point focusing on the sine-Gordon model as a primary example. We suggest a unified approach to sudden and slow quenches, where the tuning parameter λ(t) changes in time as λ(t)∼υt r , based on the adiabatic expansion of the excitation probability in powers of υ. We show that the universal scaling of the excitation probability can be understood through the singularity of the generalized adiabatic susceptibility χ 2r+2 (λ), which for sudden quenches (r=0) reduces to the fidelity susceptibility. In turn this class of susceptibilities is expressed through the moments of the connected correlation function of the quench operator. We analyze the excitations created after a sudden quench of the cosine potential using a combined approach of form-factors expansion and conformal perturbation theory for the low-energy and high-energy sector, respectively. We find the general scaling laws for the probability of exciting the system, the density of excited quasiparticles, the entropy and the heat generated after the quench. In the two limits where the sine-Gordon model maps to hard-core bosons and free massive fermions we provide the exact solutions for the quench dynamics and discuss the finite temperature generalizations.
Soliton scatterings by impurities in a short-length sine-Gordon chain
International Nuclear Information System (INIS)
Dikande, A.M.; Kofane, T.C.
1995-07-01
The scattering of soliton by impurities at the frontiers of a finite-length region of an infinite sine-Gordon chain is analyzed. The impurities consist of two isotopic inhomogeneities installed at the boundaries of the finite-length region. The soliton solution in the region is found in term of snoidal sine-Gordon soliton which properly takes into account the effects of the boundaries. By contrast, the soliton solutions in the neighboring sides of the region are obtained in terms of the so-called large-amplitude, localized kinks with limiting spatial extensions at x → ± ∞, which is equal ±π. Using the continuity of these soliton solutions at the frontiers as well as appropriate boundary conditions, it is shown that the soliton may be either i) reflected by the incident impurity; ii) trapped (with oscillating motions) between the two impurities (i.e. inside the infinite region); or iii) transmitted by the second impurity into the third, infinitely extended region. The threshold velocities for the reflection and transmission into different regions are found and shown to vary exponentially as a function of the length of the bounded region. The frequency of soliton oscillations between the impurities has also been calculated in some acceptable limit. (author). 28 refs, 1 fig
Is the energy density of the ground state of the sine-Gordon model unbounded from below for β2 > 8π?
International Nuclear Information System (INIS)
Faber, M; Ivanov, A N
2003-01-01
We discuss Coleman's theorem concerning the energy density of the ground state of the sine-Gordon model proved in Coleman S (1975 Phys. Rev. D 11 2088). According to this theorem the energy density of the ground state of the sine-Gordon model should be unbounded from below for coupling constants β 2 > 8π. The consequence of this theorem would be the non-existence of the quantum ground state of the sine-Gordon model for β 2 > 8π. We show that the energy density of the ground state in the sine-Gordon model is bounded from below even for β 2 > 8π. This result is discussed in relation to Coleman's theorem (Coleman S 1973 Commun. Math. Phys. 31 259), particle mass spectra and soliton-soliton scattering in the sine-Gordon model
Directory of Open Access Journals (Sweden)
Yair Zarmi
Full Text Available The (1+1-dimensional Sine-Gordon equation passes integrability tests commonly applied to nonlinear evolution equations. Its kink solutions (one-dimensional fronts are obtained by a Hirota algorithm. In higher space-dimensions, the equation does not pass these tests. Although it has been derived over the years for quite a few physical systems that have nothing to do with Special Relativity, the Sine-Gordon equation emerges as a non-linear relativistic wave equation. This opens the way for exploiting the tools of the Theory of Special Relativity. Using no more than the relativistic kinematics of tachyonic momentum vectors, from which the solutions are constructed through the Hirota algorithm, the existence and classification of N-moving-front solutions of the (1+2- and (1+3-dimensional equations for all N ≥ 1 are presented. In (1+2 dimensions, each multi-front solution propagates rigidly at one velocity. The solutions are divided into two subsets: Solutions whose velocities are lower than a limiting speed, c = 1, or are greater than or equal to c. To connect with concepts of the Theory of Special Relativity, c will be called "the speed of light." In (1+3-dimensions, multi-front solutions are characterized by spatial structure and by velocity composition. The spatial structure is either planar (rotated (1+2-dimensional solutions, or genuinely three-dimensional--branes. Planar solutions, propagate rigidly at one velocity, which is lower than, equal to, or higher than c. Branes must contain clusters of fronts whose speed exceeds c = 1. Some branes are "hybrids": different clusters of fronts propagate at different velocities. Some velocities may be lower than c but some must be equal to, or exceed, c. Finally, the speed of light cannot be approached from within the subset of slower-than-light solutions in both (1+2 and (1+3 dimensions.
Renormalization group study of the multi-layer sine-gordon model
International Nuclear Information System (INIS)
Nandori, I.
2005-01-01
Complete text of publication follows. We analyze the phase structure of the system of coupled sine-Gordon (SG) type field theoric models. The 'pure,' SG model is periodic in the internal space spanned by the field variable. The central subjects of investigation is the multi-layer sine-Gordon (LSG) model, where the periodicity is broken partially by the coupling terms between the layers each of which is described by a scalar field, where the second term on the r.h.s. describes the interaction of the layers. Here, we dis- cuss the generalization of the results obtained for the two-layer sine-Gordon model found in the previous study. Besides the obvious field theoretical interest, the LSG model has been used to describe the vortex properties of high transition temperature superconductors, and the extension of the previous analysis to a general N-layer model is necessary for a description of the critical behaviour of vortices in realistic multi-layer systems. The couplings between the layers can be considered as mass terms. Since the periodicity of the LSG model has been broken only partially, the N-layer model has always a single zero mass eigenvalue. The presence of this single zero mass eigenvalue is found to be decisive with respect to the phase structure of the N-layer models. By a suitable rotation of the field variables, we identify the periodic mode (which corresponds to the zero mass eigenvalue) and N - 1 non-periodic modes (with explicit mass terms). The N - 1 non-periodic modes have a trivial IR scaling which holds independently of β which has been proven consistently using (i) the non-perturbative renormalization group study of the rotated model, (ii) the Gaussian integration about the vanishing-field saddle point. Due to the presence of the periodic mode the model undergoes a Kosterlitz-Thouless type phase transition which occurs at a coupling parameter β c 2 = 8Nπ, where N is the number of layers. The critical value β c 2 corresponds to the critical
Chiral vertex operators in off-conformal theory: Sine-Gordon example
International Nuclear Information System (INIS)
Chang, S.; Rajaraman, R.
1996-01-01
We study chiral vertex operators in sine-Gordon (SG) theory, viewed as an off-conformal system. We find that these operators, which would have been primary fields in the conformal limit, have interesting properties in the SG model. Some of them commute with the cosine interaction term in the Hamiltonian at a finite separation. Their Heisenberg equations of motion are local in space. An example of such vertex operators is Mandelstam close-quote s bosonic representation of the Fermi field. Another example is a set of vertex operators of topological number 2. We show how to construct conserved nonlocal currents from these operators. In the presence of the nonconformal interactions, these nonlocal currents have unique Lorentz spins. copyright 1996 The American Physical Society
SOLITONES KINK Y ANTIKENK EN LA ECUACIÓN DE SINE -GORDON
Directory of Open Access Journals (Sweden)
Francis Armando Segovia Chaves
2012-08-01
Full Text Available La ecuación de sine-Gordon es una ecuación diferencial no lineal, tiene grandes aplicaciones no solamente en la teoría de campos relativistas, sino también encuentra aplicación en la física del estado sólido y en el transporte de señales en la fibra óptica. En este trabajo se estudian dos soluciones que tiene esta ecuación diferencial como lo son las soluciones tipo solitón kink y soluciones tipo solitón antikink. Para obtener dichas soluciones se realiza el modelamiento matemático y se representa gráficamente su evolución espacio temporal.
Collective coordinates theory for discrete soliton ratchets in the sine-Gordon model
Sánchez-Rey, Bernardo; Quintero, Niurka R.; Cuevas-Maraver, Jesús; Alejo, Miguel A.
2014-10-01
A collective coordinate theory is developed for soliton ratchets in the damped discrete sine-Gordon model driven by a biharmonic force. An ansatz with two collective coordinates, namely the center and the width of the soliton, is assumed as an approximated solution of the discrete nonlinear equation. The dynamical equations of these two collective coordinates, obtained by means of the generalized travelling wave method, explain the mechanism underlying the soliton ratchet and capture qualitatively all the main features of this phenomenon. The numerical simulation of these equations accounts for the existence of a nonzero depinning threshold, the nonsinusoidal behavior of the average velocity as a function of the relative phase between the harmonics of the driver, the nonmonotonic dependence of the average velocity on the damping, and the existence of nontransporting regimes beyond the depinning threshold. In particular, it provides a good description of the intriguing and complex pattern of subspaces corresponding to different dynamical regimes in parameter space.
Energy Technology Data Exchange (ETDEWEB)
Misumi, Tatsuhiro [Department of Mathematical Science, Akita University,1-1 Tegata Gakuen-machi, Akita 010-8502 (Japan); Research and Education Center for Natural Sciences,Keio University, 4-1-1 Hiyoshi, Yokohama, Kanagawa 223-8521 (Japan); Nitta, Muneto; Sakai, Norisuke [Department of Physics, and Research and Education Center for Natural Sciences,Keio University, 4-1-1 Hiyoshi, Yokohama, Kanagawa 223-8521 (Japan)
2015-09-23
We compute multi-instanton amplitudes in the sine-Gordon quantum mechanics (periodic cosine potential) by integrating out quasi-moduli parameters corresponding to separations of instantons and anti-instantons. We propose an extension of Bogomolnyi-Zinn-Justin prescription for multi-instanton configurations and an appropriate subtraction scheme. We obtain the multi-instanton contributions to the energy eigenvalue of the lowest band at the zeroth order of the coupling constant. For the configurations with only instantons (anti-instantons), we obtain unambiguous results. For those with both instantons and anti-instantons, we obtain results with imaginary parts, which depend on the path of analytic continuation. We show that the imaginary parts of the multi-instanton amplitudes precisely cancel the imaginary parts of the Borel resummation of the perturbation series, and verify that our results completely agree with those based on the uniform-WKB calculations, thus confirming the resurgence structure: divergent perturbation series combined with the nonperturbative multi-instanton contributions conspire to give unambiguous results. We also study the neutral bion contributions in the ℂP{sup N−1} model on ℝ{sup 1}×S{sup 1} with a small circumference, taking account of the relative phase moduli between the fractional instanton and anti-instanton. We find that the sign of the interaction potential depends on the relative phase moduli, and that both the real and imaginary parts resulting from quasi-moduli integral of the neutral bion get quantitative corrections compared to the sine-Gordon quantum mechanics.
International Nuclear Information System (INIS)
Poghossian, R.H.
2000-01-01
In an angular quantization approach a perturbation theory for the Massive Thirring Model (MTM) is developed, which allows us to calculate vacuum expectation values of exponential fields in sine-Gordon theory near the free fermion point in first order of the MTM coupling constant g. The Hankel transforms play an important role when carrying out these calculations. The expression we have found coincides with that of the direct expansion over g of the exact formula conjectured by Lukyanov and Zamolodchikov
Sine-Gordon quantum field theory on the half-line with quantum boundary degrees of freedom
International Nuclear Information System (INIS)
Baseilhac, P.; Koizumi, K.
2003-01-01
The sine-Gordon model on the half-line with a dynamical boundary introduced by Delius and one of the authors is considered at quantum level. Classical boundary conditions associated with classical integrability are shown to be preserved at quantum level too. Non-local conserved charges are constructed explicitly in terms of the field and boundary operators. We solve the intertwining equation associated with a certain coideal subalgebra of U q (sl 2 -bar) generated by these non-local charges. The corresponding solution is shown to satisfy quantum boundary Yang-Baxter equations. Up to an exact relation between the quantization length of the boundary quantum mechanical system and the sine-Gordon coupling constant, we conjecture the soliton/antisoliton reflection matrix and bound states reflection matrices. The structure of the boundary state is then considered, and shown to be divided in two sectors. Also, depending on the sine-Gordon coupling constant a finite set of boundary bound states are identified. Taking the analytic continuation of the coupling, the corresponding boundary sinh-Gordon model is briefly discussed. In particular, the particle reflection factor enjoys weak-strong coupling duality
International Nuclear Information System (INIS)
Watanabe, S.; Strogatz, S.H.; van der Zant, H.S.J.; Orlando, T.P.
1995-01-01
We analyze the damped driven discrete sine-Gordon equation. For underdamped, highly discrete systems, we show that whirling periodic solutions undergo parametric instabilities at certain drive strengths. The theory predicts novel resonant steps in the current-voltage characteristics of discrete Josephson rings, occurring in the return path of the subgap region. We have observed these steps experimentally in a ring of 8 underdamped junctions. An unusual prediction, verified experimentally, is that such steps occur even if there are no vortices in the ring. Numerical simulations indicate that complex spatiotemporal behavior occurs past the onset of instability
Yaşar, Elif; Yıldırım, Yakup; Yaşar, Emrullah
2018-06-01
This paper devotes to conformable fractional space-time perturbed Gerdjikov-Ivanov (GI) equation which appears in nonlinear fiber optics and photonic crystal fibers (PCF). We consider the model with full nonlinearity in order to give a generalized flavor. The sine-Gordon equation approach is carried out to model equation for retrieving the dark, bright, dark-bright, singular and combined singular optical solitons. The constraint conditions are also reported for guaranteeing the existence of these solitons. We also present some graphical simulations of the solutions for better understanding the physical phenomena of the behind the considered model.
Influence of solitons in the initial state on chaos in the driven damped sine-Gordon system
Energy Technology Data Exchange (ETDEWEB)
Bishop, A R; Fesser, K; Lomdahl, P S; Trullinger, S E
1983-01-01
The appearance of chaos in the a.c. driven, damped sine-Gordon equation is studied numerically. Several transitions from periodic to chaotic behavior are investigated in detail for flat initial conditions. Spatial structures (breather, kink) in the initial conditions smooth out many of these transitions and give rise to an interesting symbiosis of time and spatial intermittency. This symbiosis appears to be due to the competition between the background tendency towards chaos and the system's preference to maintain a spatial pattern. The way that this competition is relieved is also found to depend very strongly on symmetry in the initial conditions.
International Nuclear Information System (INIS)
Li Qi; Zhang Dajun; Chen Dengyuan
2010-01-01
N-soliton solutions of the hierarchy of non-isospectral mKdV equation with self-consistent sources and the hierarchy of non-isospectral sine-Gordon equation with self-consistent sources are obtained via the inverse scattering transform. (general)
International Nuclear Information System (INIS)
Garbaczewski, P.
1981-01-01
Both quantum and classical sine--Gordon fields can be built out of the fundamental free neutral massive excitations, which quantally obey the Bose--Einstein statistics. At the roots of the ''boson-fermion reciprocity'' invented by Coleman, lies the spin 1/2 approximation of the underlying Bose system. By generalizing the coherent state methods to incorporate non-Fock quantum structures and to give account of the so-called boson transformation theory, we construct the carrier Hilbert space H/sub SG/ for quantum soliton operators. The h→0 limit of state expectation values of these operators among pure coherentlike states in H/sub SG/ reproduces the classical sine--Gordon field. The related (classical and quantum) spin 1/2 xyz Heisenberg model field is built out of the fundamental sine--Gordon excitations, and hence can be consistently defined on the appropriate subset of the quantum soliton Hilbert space H/sub x/yz . A correct classical limit is here shown to arise for the Heisenberg system: phase manifolds of the classical Heisenberg and sine--Gordon systems cannot be then viewed independently as a consequence of the quantum relation
Kevrekidis, Panayotis; Williams, Floyd
2014-01-01
The sine-Gordon model is a ubiquitous model of Mathematical Physics with a wide range of applications extending from coupled torsion pendula and Josephson junction arrays to gravitational and high-energy physics models. The purpose of this book is to present a summary of recent developments in this field, incorporating both introductory background material, but also with a strong view towards modern applications, recent experiments, developments regarding the existence, stability, dynamics and asymptotics of nonlinear waves that arise in the model. This book is of particular interest to a wide range of researchers in this field, but serves as an introductory text for young researchers and students interested in the topic. The book consists of well-selected thematic chapters on diverse mathematical and physical aspects of the equation carefully chosen and assigned.
International Nuclear Information System (INIS)
Wingate, C.A.
1978-01-01
Two major problems are studied in this thesis. The first is a numerical search for a stable oscillating mode in the Phi4 equation similar to the one that is known for the sine-Gordon equation. Starting with a widely separated soliton and anti-soliton traveling toward each other, it is observed, after a long period of time (t = 2800), that the solitons form a quasistable oscillating state. An interesting, previously unknown structure in the interaction depending on the initial velocity and initial separation is found and studied in detail. The second topic covered here is a study of the phi4, KdV and sine-Gordon equations when the coefficients vary slowly with time. A general first order solution is found for the wave equation with a non-linear potential and is applied to the phi4 and sine-Gordon potentials. In doing this it is found that the conservation of momentum is equivalent order by order to the secular conditions. Deficiencies in existing calculations for the KdV equation are pointed out through the use of adiabatic invariants and numerical calculations
International Nuclear Information System (INIS)
Lashkevich, Michael; Pugai, Yaroslav
2013-01-01
We continue the study of form factors of descendant operators in the sinh- and sine-Gordon models in the framework of the algebraic construction proposed in [1]. We find the algebraic construction to be related to a particular limit of the tensor product of the deformed Virasoro algebra and a suitably chosen Heisenberg algebra. To analyze the space of local operators in the framework of the form factor formalism we introduce screening operators and construct singular and cosingular vectors in the Fock spaces related to the free field realization of the obtained algebra. We show that the singular vectors are expressed in terms of the degenerate Macdonald polynomials with rectangular partitions. We study the matrix elements that contain a singular vector in one chirality and a cosingular vector in the other chirality and find them to lead to the resonance identities already known in the conformal perturbation theory. Besides, we give a new derivation of the equation of motion in the sinh-Gordon theory, and a new representation for conserved currents
Directory of Open Access Journals (Sweden)
V. Bacsó
2015-12-01
Full Text Available In this paper we study the c-function of the sine-Gordon model taking explicitly into account the periodicity of the interaction potential. The integration of the c-function along trajectories of the non-perturbative renormalization group flow gives access to the central charges of the model in the fixed points. The results at vanishing frequency β2, where the periodicity does not play a role, are retrieved and the independence on the cutoff regulator for small frequencies is discussed. Our findings show that the central charge obtained integrating the trajectories starting from the repulsive low-frequencies fixed points (β2<8π to the infra-red limit is in good quantitative agreement with the expected Δc=1 result. The behavior of the c-function in the other parts of the flow diagram is also discussed. Finally, we point out that including also higher harmonics in the renormalization group treatment at the level of local potential approximation is not sufficient to give reasonable results, even if the periodicity is taken into account. Rather, incorporating the wave-function renormalization (i.e. going beyond local potential approximation is crucial to get sensible results even when a single frequency is used.
Exterior calculus and two-dimensional supersymmetric models
International Nuclear Information System (INIS)
Sciuto, S.
1980-01-01
An important property of the calculus of differential forms on superspace is pointed out, and an economical way to treat the linear problem associated with certain supersymmetric two-dimensional models is discussed. A generalization of the super sine-Gordon model is proposed; its bosonic limit is a new model whose associate linear set has an SU(3) structure. (orig.)
Path-integral bosonization of two-dimensional massive Q.C.D
International Nuclear Information System (INIS)
Rego Monteiro, M.A. do.
1984-01-01
The fermionic determinant for two-dimensional QCD with massive fermions by means of Seeley's technique is evaluated. Apart from a gluon-mass term this determinant contains a Wess-Zumino anomaly term and a non-abelian extension of the Sine-Gordon. (Author) [pt
Two-dimensional quantum electrodynamics as a model in the constructive quantum field theory
International Nuclear Information System (INIS)
Ito, K.R.
1976-01-01
We investigate two-dimensional quantum electrodynamics((QED) 2 ) type models on the basis of the Hamiltonian formalism of a vector field. The transformation into a sine-Gordon equation is clarified as a generalized mass-shift transformation through canonical linear transformations. (auth.)
Mannheim Curves in Nonflat 3-Dimensional Space Forms
Directory of Open Access Journals (Sweden)
Wenjing Zhao
2015-01-01
Full Text Available We consider the Mannheim curves in nonflat 3-dimensional space forms (Riemannian or Lorentzian and we give the concept of Mannheim curves. In addition, we investigate the properties of nonnull Mannheim curves and their partner curves. We come to the conclusion that a necessary and sufficient condition is that a linear relationship with constant coefficients will exist between the curvature and the torsion of the given original curves. In the case of null curve, we reveal that there are no null Mannheim curves in the 3-dimensional de Sitter space.
Reflection of sine-Gordon breathers
DEFF Research Database (Denmark)
Olsen, O. H.; Samuelsen, Mogens Rugholm
1981-01-01
The influence of a boundary on a breather traveling in a Josephson line cavity is examined by means of numerical computations. For a passive termination the breather is reflected into a breather of less energy; when the characteristic impedance of the line equals the external load resistor the br...
Four-dimensional hilbert curves for R-trees
DEFF Research Database (Denmark)
Haverkort, Herman; Walderveen, Freek van
2011-01-01
Two-dimensional R-trees are a class of spatial index structures in which objects are arranged to enable fast window queries: report all objects that intersect a given query window. One of the most successful methods of arranging the objects in the index structure is based on sorting the objects...... according to the positions of their centers along a two-dimensional Hilbert space-filling curve. Alternatively, one may use the coordinates of the objects' bounding boxes to represent each object by a four-dimensional point, and sort these points along a four-dimensional Hilbert-type curve. In experiments...
International Nuclear Information System (INIS)
Feng Baofeng; Maruno, Ken-ichi; Inoguchi, Jun-ichi; Kajiwara, Kenji; Ohta, Yasuhiro
2011-01-01
We consider integrable discretizations of some soliton equations associated with the motions of plane curves: the Wadati-Konno-Ichikawa elastic beam equation, the complex Dym equation and the short pulse equation. They are related to the modified KdV or the sine-Gordon equations by the hodograph transformations. Based on the observation that the hodograph transformations are regarded as the Euler-Lagrange transformations of the curve motions, we construct the discrete analogues of the hodograph transformations, which yield integrable discretizations of those soliton equations. (paper)
Solitons in one-dimensional antiferromagnetic chains
International Nuclear Information System (INIS)
Pires, A.S.T.; Talim, S.L.; Costa, B.V.
1989-01-01
We study the quantum-statistical mechanics, at low temperatures, of a one-dimensional antiferromagnetic Heisenberg model with two anisotropies. In the weak-coupling limit we determine the temperature dependences of the soliton energy and the soliton density. We have found that the leading correction to the sine-Gordon (SG) expression for the soliton density and the quantum soliton energy comes from the out-of-plane magnon mode, not present in the pure SG model. We also show that when an external magnetic field is applied, the chain supports a new type of kink, where the sublattices rotate in opposite directions
Equilibrium spherically curved two-dimensional Lennard-Jones systems
Voogd, J.M.; Sloot, P.M.A.; van Dantzig, R.
2005-01-01
To learn about basic aspects of nano-scale spherical molecular shells during their formation, spherically curved two-dimensional N-particle Lennard-Jones systems are simulated, studying curvature evolution paths at zero-temperature. For many N-values (N < 800) equilibrium configu- rations are traced
International Nuclear Information System (INIS)
Hansen, J.B.; Divin, Y.Y.; Mygind, J.
1986-01-01
We report on the observation of full splitting of the first zero-field steps in the I-V curves of Josephson transmission lines of intermediate length Lroughly-equal(3--5)lambda/sub J/, where lambda/sub J/ is the Josephson penetration length. We study in detail how this splitting of the step into two branches depends on the temperature of the junction and on a weak applied magnetic field. We relate the splitting to excitations in the junctions whose behavior is described by the perturbed Sine-Gordon equation
Intertwined Hamiltonians in two-dimensional curved spaces
International Nuclear Information System (INIS)
Aghababaei Samani, Keivan; Zarei, Mina
2005-01-01
The problem of intertwined Hamiltonians in two-dimensional curved spaces is investigated. Explicit results are obtained for Euclidean plane, Minkowski plane, Poincare half plane (AdS 2 ), de Sitter plane (dS 2 ), sphere, and torus. It is shown that the intertwining operator is related to the Killing vector fields and the isometry group of corresponding space. It is shown that the intertwined potentials are closely connected to the integral curves of the Killing vector fields. Two problems are considered as applications of the formalism presented in the paper. The first one is the problem of Hamiltonians with equispaced energy levels and the second one is the problem of Hamiltonians whose spectrum is like the spectrum of a free particle
Two dimensional hybrid simulation of a curved bow shock
International Nuclear Information System (INIS)
Thomas, V.A.; Winske, D.
1990-01-01
Results are presented from two dimensional hybrid simulations of curved collisionless supercritical shocks, retaining both quasi-perpendicular and quasi-parallel sections of the shock in order to study the character and origin of the foreshock ion population. The simulations demonstrate that the foreshock ion population is dominated by ions impinging upon the quasi-parallel side of the shock, while nonlocal transport from the quasi-perpendicular side of the shock into the foreshock region is minimal. Further, it is shown that the ions gain energy by drifting significantly in the direction of the convection electric field through multiple shock encounters
Higher dimensional curved domain walls on Kähler surfaces
Energy Technology Data Exchange (ETDEWEB)
Akbar, Fiki T., E-mail: ftakbar@fi.itb.ac.id [Theoretical Physics Laboratory, Theoretical High Energy Physics and Instrumentation Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha no. 10 Bandung, 40132 (Indonesia); Gunara, Bobby E., E-mail: bobby@fi.itb.ac.id [Theoretical Physics Laboratory, Theoretical High Energy Physics and Instrumentation Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha no. 10 Bandung, 40132 (Indonesia); Radjabaycolle, Flinn C. [Theoretical Physics Laboratory, Theoretical High Energy Physics and Instrumentation Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha no. 10 Bandung, 40132 (Indonesia); Departement of Physics, Faculty of Mathematics and Natural Sciences, Cendrawasih University, Jl. Kampwolker Kampus Uncen Baru Waena-Jayapura 99351 (Indonesia); Wijaya, Rio N. [Theoretical Physics Laboratory, Theoretical High Energy Physics and Instrumentation Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha no. 10 Bandung, 40132 (Indonesia)
2017-03-15
In this paper we study some aspects of curved BPS-like domain walls in higher dimensional gravity theory coupled to scalars where the scalars span a complex Kähler surface with scalar potential turned on. Assuming that a fake superpotential has a special form which depends on Kähler potential and a holomorphic function, we prove that BPS-like equations have a local unique solution. Then, we analyze the vacuum structure of the theory including their stability using dynamical system and their existence in ultraviolet-infrared regions using renormalization group flow.
Higher dimensional curved domain walls on Kähler surfaces
International Nuclear Information System (INIS)
Akbar, Fiki T.; Gunara, Bobby E.; Radjabaycolle, Flinn C.; Wijaya, Rio N.
2017-01-01
In this paper we study some aspects of curved BPS-like domain walls in higher dimensional gravity theory coupled to scalars where the scalars span a complex Kähler surface with scalar potential turned on. Assuming that a fake superpotential has a special form which depends on Kähler potential and a holomorphic function, we prove that BPS-like equations have a local unique solution. Then, we analyze the vacuum structure of the theory including their stability using dynamical system and their existence in ultraviolet-infrared regions using renormalization group flow.
International Nuclear Information System (INIS)
Sun Qing; Hu Xinghua; Liu, W. M.; Xie, X. C.; Ji Anchun
2011-01-01
We investigate optomechanical coupling between one-dimensional interacting bosons and the electromagnetic field in a high-finesse optical cavity. We show that by tuning interatomic interactions, one can realize effective optomechanics with mechanical resonators ranging from side-mode excitations of a Bose-Einstein condensate (BEC) to particle-hole excitations of a Tonks-Girardeau (TG) gas. We propose that this unique feature can be formulated to detect the BEC-TG gas crossover and measure the sine-Gordon transition continuously and nondestructively.
International Nuclear Information System (INIS)
Carvalho-Santos, V.L.; Apolonio, F.A.; Oliveira-Neto, N.M.
2013-01-01
We study the Heisenberg model on cylindrically symmetric curved surfaces. Two kinds of excitations are considered. The first is given by the isotropic regime, yielding the sine-Gordon equation and π solitons are predicted. The second one is given by the XY model, leading to a vortex turning around the surface. Helical states are also considered, however, topological arguments cannot be used to ensure its stability. The energy and the anisotropy parameter which stabilizes the vortex state are explicitly calculated for two surfaces: catenoid and hyperboloid. The results show that the anisotropy and the vortex energy depends on the underlying geometry. -- Highlights: •Applying the anisotropic Heisenberg model on curved surfaces. •Appearance of topological solitons on curved surfaces with cylindrical symmetry. •Calculus of the vortex energy, which depends on curvature. •Discussion on features of non-topological helical-like states. •Vortex stability ensured by the anisotropy parameter value
Super integrable four-dimensional autonomous mappings
International Nuclear Information System (INIS)
Capel, H W; Sahadevan, R; Rajakumar, S
2007-01-01
A systematic investigation of the complete integrability of a fourth-order autonomous difference equation of the type w(n + 4) = w(n)F(w(n + 1), w(n + 2), w(n + 3)) is presented. We identify seven distinct families of four-dimensional mappings which are super integrable and have three (independent) integrals via a duality relation as introduced in a recent paper by Quispel, Capel and Roberts (2005 J. Phys. A: Math. Gen. 38 3965-80). It is observed that these seven families can be related to the four-dimensional symplectic mappings with two integrals including all the four-dimensional periodic reductions of the integrable double-discrete modified Korteweg-deVries and sine-Gordon equations treated in an earlier paper by two of us (Capel and Sahadevan 2001 Physica A 289 86-106)
Higher-Dimensional Solitons Stabilized by Opposite Charge
Binder, B
2002-01-01
In this paper it is shown how higher-dimensional solitons can be stabilized by a topological phase gradient, a field-induced shift in effective dimensionality. As a prototype, two instable 2-dimensional radial symmetric Sine-Gordon extensions (pulsons) are coupled by a sink/source term such, that one becomes a stable 1d and the other a 3d wave equation. The corresponding physical process is identified as a polarization that fits perfectly to preliminary considerations regarding the nature of electric charge and background of 1/137. The coupling is iterative with convergence limit and bifurcation at high charge. It is driven by the topological phase gradient or non-local Gauge potential that can be mapped to a local oscillator potential under PSL(2,R).
Geometrical aspects of solvable two dimensional models
International Nuclear Information System (INIS)
Tanaka, K.
1989-01-01
It was noted that there is a connection between the non-linear two-dimensional (2D) models and the scalar curvature r, i.e., when r = -2 the equations of motion of the Liouville and sine-Gordon models were obtained. Further, solutions of various classical nonlinear 2D models can be obtained from the condition that the appropriate curvature two form Ω = 0, which suggests that these models are closely related. This relation is explored further in the classical version by obtaining the equations of motion from the evolution equations, the infinite number of conserved quantities, and the common central charge. The Poisson brackets of the solvable 2D models are specified by the Virasoro algebra. 21 refs
Radial sine-Gordon kinks as sources of fast breathers
DEFF Research Database (Denmark)
Caputo, Jean Guy; Sørensen, Mads Peter
2013-01-01
all outgoing radiation. As the kink shrinks toward r, before the collision, its motion is well described by a simple law derived from the conservation of energy. In two dimensions for r ≤ 2, the collision disintegrates the kink into a fast breather, while for r ≥ 4 we obtain a kink-breather metastable...... state where breathers are shed at each kink “return.” In three and higher dimensions d, an additional kink-oscillon state appears for small r. On the application side, the kink disintegration opens the way for new types of terahertz microwave generators....
On a family of (1+1)-dimensional scalar field theory models: Kinks, stability, one-loop mass shifts
Energy Technology Data Exchange (ETDEWEB)
Alonso-Izquierdo, A., E-mail: alonsoiz@usal.es [Departamento de Matematica Aplicada and IUFFyM, Universidad de Salamanca (Spain); Mateos Guilarte, J. [Departamento de Fisica Fundamental and IUFFyM, Universidad de Salamanca (Spain)
2012-09-15
In this paper we construct a one-parametric family of (1+1)-dimensional one-component scalar field theory models supporting kinks. Inspired by the sine-Gordon and {phi}{sup 4} models, we look at all possible extensions such that the kink second-order fluctuation operators are Schroedinger differential operators with Poeschl-Teller potential wells. In this situation, the associated spectral problem is solvable and therefore we shall succeed in analyzing the kink stability completely and in computing the one-loop quantum correction to the kink mass exactly. When the parameter is a natural number, the family becomes the hierarchy for which the potential wells are reflectionless, the two first levels of the hierarchy being the sine-Gordon and {phi}{sup 4} models. - Highlights: Black-Right-Pointing-Pointer We construct a family of scalar field theory models supporting kinks. Black-Right-Pointing-Pointer The second-order kink fluctuation operators involve Poeschl-Teller potential wells. Black-Right-Pointing-Pointer We compute the one-loop quantum correction to the kink mass with different methods.
Geodesics on a hot plate: an example of a two-dimensional curved space
International Nuclear Information System (INIS)
Erkal, Cahit
2006-01-01
The equation of the geodesics on a hot plate with a radially symmetric temperature profile is derived using the Lagrangian approach. Numerical solutions are presented with an eye towards (a) teaching two-dimensional curved space and the metric used to determine the geodesics (b) revealing some characteristics of two-dimensional curved spacetime and (c) providing insight into understanding the curved space which emerges in teaching relativity. In order to provide a deeper insight, we also present the analytical solutions and show that they represent circles whose characteristics depend on curvature of the space, conductivity and the coefficient of thermal expansion
Geodesics on a hot plate: an example of a two-dimensional curved space
Energy Technology Data Exchange (ETDEWEB)
Erkal, Cahit [Department of Geology, Geography, and Physics, University of Tennessee, Martin, TN 38238 (United States)
2006-07-01
The equation of the geodesics on a hot plate with a radially symmetric temperature profile is derived using the Lagrangian approach. Numerical solutions are presented with an eye towards (a) teaching two-dimensional curved space and the metric used to determine the geodesics (b) revealing some characteristics of two-dimensional curved spacetime and (c) providing insight into understanding the curved space which emerges in teaching relativity. In order to provide a deeper insight, we also present the analytical solutions and show that they represent circles whose characteristics depend on curvature of the space, conductivity and the coefficient of thermal expansion.
Dirac equation in 5- and 6-dimensional curved space-time manifolds
International Nuclear Information System (INIS)
Vladimirov, Yu.S.; Popov, A.D.
1984-01-01
The program of plotting unified multidimensional theory of gravitation, electromagnetism and electrically charged matter with transition from 5-dimensional variants to 6-dimensional theory possessing signature (+----+) is developed. For recording the Dirac equation in 5- and 6-dimensional curved space-time manifolds the tetrad formalism and γ-matrix formulation of the General Relativity Theory are used. It is shown that the 6-dimensional theory case unifies the two private cases of 5-dimensional theory and corresponds to two possibilities of the theory developed by Kadyshevski
Quantization of the Type II superstring in a curved six-dimensional background
International Nuclear Information System (INIS)
Berkovits, Nathan
2000-01-01
A sigma model action with N=2 D=6 superspace variables is constructed for the Type II superstring compactified to six curved dimensions with Ramond-Ramond flux. The action can be quantized since the sigma model is linear when the six-dimensional space-time is flat. When the six-dimensional space-time is AdS 3 xS 3 , the action reduces to one found earlier with Vafa and Witten
Determination of Sight Distance on a Combined Crest and Circular Curve in a Three Dimensional Space
Directory of Open Access Journals (Sweden)
Chiu Liu, PhD, PE, PTOE
2012-06-01
Full Text Available The sight distance (SD on a two-dimensional (2-d curve, namely, a vertical curve or a horizontal curve, has been well understood and documented for roadway geometric design in literature. In reality, three-dimensional (3-d curves can be found along ramps, connectors, and often mountain roads. The sight distance on these 3-d curves, which may vary with driver's location, has not been tackled in literature on an exact analytic setting. By integrating human-vehicle-roadway interaction, the formulas for computing the SD on a 3-d curve are derived the first time on an analytic framework. The crest curve SD that has been used in various literatures, can be deduced from these derived formulas as special limiting cases. Practitioners can easily apply theses user-friendly formulas or equations on a Microsoft Excel spread sheet to calculate 3-d SD on a roadway with sufficient roadside clearance. In addition, this framework can be extended easily to cope with various scenarios in which obstacles partially blocking driver's sight are present in a roadway environment.
Tuset-Sanchis, Luis; Castro-Palacio, Juan C.; Gómez-Tejedor, José A.; Manjón, Francisco J.; Monsoriu, Juan A.
2015-01-01
A smartphone acceleration sensor is used to study two-dimensional harmonic oscillations. The data recorded by the free android application, Accelerometer Toy, is used to determine the periods of oscillation by graphical analysis. Different patterns of the Lissajous curves resulting from the superposition of harmonic motions are illustrated for…
Dirac Equation in (1 +1 )-Dimensional Curved Spacetime and the Multiphoton Quantum Rabi Model
Pedernales, J. S.; Beau, M.; Pittman, S. M.; Egusquiza, I. L.; Lamata, L.; Solano, E.; del Campo, A.
2018-04-01
We introduce an exact mapping between the Dirac equation in (1 +1 )-dimensional curved spacetime (DCS) and a multiphoton quantum Rabi model (QRM). A background of a (1 +1 )-dimensional black hole requires a QRM with one- and two-photon terms that can be implemented in a trapped ion for the quantum simulation of Dirac particles in curved spacetime. We illustrate our proposal with a numerical analysis of the free fall of a Dirac particle into a (1 +1 )-dimensional black hole, and find that the Zitterbewegung effect, measurable via the oscillatory trajectory of the Dirac particle, persists in the presence of gravity. From the duality between the squeezing term in the multiphoton QRM and the metric coupling in the DCS, we show that gravity generates squeezing of the Dirac particle wave function.
Evaluation of viewing experiences induced by a curved three-dimensional display
Mun, Sungchul; Park, Min-Chul; Yano, Sumio
2015-10-01
Despite an increased need for three-dimensional (3-D) functionality in curved displays, comparisons pertinent to human factors between curved and flat panel 3-D displays have rarely been tested. This study compared stereoscopic 3-D viewing experiences induced by a curved display with those of a flat panel display by evaluating subjective and objective measures. Twenty-four participants took part in the experiments and viewed 3-D content with two different displays (flat and curved 3-D display) within a counterbalanced and within-subject design. For the 30-min viewing condition, a paired t-test showed significantly reduced P300 amplitudes, which were caused by engagement rather than cognitive fatigue, in the curved 3-D viewing condition compared to the flat 3-D viewing condition at P3 and P4. No significant differences in P300 amplitudes were observed for 60-min viewing. Subjective ratings of realness and engagement were also significantly higher in the curved 3-D viewing condition than in the flat 3-D viewing condition for 30-min viewing. Our findings support that curved 3-D displays can be effective for enhancing engagement among viewers based on specific viewing times and environments.
Deriving Sight Distance on a Compound Sag and Circular Curve in a Three Dimensional Space
Directory of Open Access Journals (Sweden)
Chiu Liu, PhD, PE, PTOE
2012-09-01
Full Text Available Insufficient roadway sight distance (SD may become a contribution factor to traffic collisions or other unsafe traffic maneuvers. The sight distance (SD for a two-dimensional (2-d sag or circular curve has been addressed in detail in various traffic engineering literatures. Although three-dimensional (3-d compound sag and circular curves are often found along ramps, connectors, and mountain roads, the sight distances for these compound curves are yet to be analyzed on an exact analytic setting. By considering human-vehicle-roadway interaction, the formulas for computing the SD on a 3-d curve are derived the first time on a unified analytic framework. The 2-d sag curve SD can also be deduced from these derived formulas as special limiting cases. Practitioners can easily program these formulas or equations on a user-friendly Microsoft Excel spread sheet to calculate 3-d SD on most roadways with roadside clearance. This framework can be extended to estimate SD on roadways with obstacles partially blocking vehicle headlight beams. 6.
Multi-Band Light Curves from Two-Dimensional Simulations of Gamma-Ray Burst Afterglows
MacFadyen, Andrew
2010-01-01
The dynamics of gamma-ray burst outflows is inherently multi-dimensional. 1.) We present high resolution two-dimensional relativistic hydrodynamics simulations of GRBs in the afterglow phase using adaptive mesh refinement (AMR). Using standard synchrotron radiation models, we compute multi-band light curves, from the radio to X-ray, directly from the 2D hydrodynamics simulation data. We will present on-axis light curves for both constant density and wind media. We will also present off-axis light curves relevant for searches for orphan afterglows. We find that jet breaks are smoothed due to both off-axis viewing and wind media effects. 2.) Non-thermal radiation mechanisms in GRB afterglows require substantial magnetic field strengths. In turbulence driven by shear instabilities in relativistic magnetized gas, we demonstrate that magnetic field is naturally amplified to half a percent of the total energy (epsilon B = 0.005). We will show high resolution three dimensional relativistic MHD simulations of this process as well as particle in cell (PIC) simulations of mildly relativistic collisionless shocks.
Proton conductivity in quasi-one dimensional hydrogen-bonded systems: A nonlinear approach
International Nuclear Information System (INIS)
Tsironis, G.; Phevmatikos, S.
1988-01-01
Defect formation and transport in a hydrogen-bonded system is studied via a two-sublattice soliton-bearing one-dimensional model. Ionic and orientational defects are associated with distinct nonlinear topological excitations in the present model. The dynamics of these excitations is studied both analytically and with the use of numerical simulations. It is shown that the two types of defects are soliton solutions of a double Sine--Gordon equation which describes the motion of the protons in the long-wavelength limit. With each defect there is an associated deformation in the ionic lattice that, for small speeds, follows the defect dynamically albeit resisting its motion. Free propagation as well as collision properties of the proton solitons are presented. 33 refs., 10 figs
Three-dimensional effects of curved plasma actuators in quiescent air
International Nuclear Information System (INIS)
Wang Chincheng; Durscher, Ryan; Roy, Subrata
2011-01-01
This paper presents results on a new class of curved plasma actuators for the inducement of three-dimensional vortical structures. The nature of the fluid flow inducement on a flat plate, in quiescent conditions, due to four different shapes of dielectric barrier discharge (DBD) plasma actuators is numerically investigated. The three-dimensional plasma kinetic equations are solved using our in-house, finite element based, multiscale ionized gas (MIG) flow code. Numerical results show electron temperature and three dimensional plasma force vectors for four shapes, which include linear, triangular, serpentine, and square actuators. Three-dimensional effects such as pinching and spreading the neighboring fluid are observed for serpentine and square actuators. The mechanisms of vorticity generation for DBD actuators are discussed. Also the influence of geometric wavelength (λ) and amplitude (Λ) of the serpentine and square actuators on vectored thrust inducement is predicted. This results in these actuators producing significantly better flow mixing downstream as compared to the standard linear actuator. Increasing the wavelengths of serpentine and square actuators in the spanwise direction is shown to enhance the pinching effect giving a much higher vertical velocity. On the contrary, changing the amplitude of the curved actuator varies the streamwise velocity significantly influencing the near wall jet. Experimental data for a serpentine actuator are also reported for validation purpose.
On renormalisation of the quantum stress tensor in curved space-time by dimensional regularisation
International Nuclear Information System (INIS)
Bunch, T.S.
1979-01-01
Using dimensional regularisation, a prescription is given for obtaining a finite renormalised stress tensor in curved space-time. Renormalisation is carried out by renormalising coupling constants in the n-dimensional Einstein equation generalised to include tensors which are fourth order in derivatives of the metric. Except for the special case of a massless conformal field in a conformally flat space-time, this procedure is not unique. There exists an infinite one-parameter family of renormalisation ansatze differing from each other in the finite renormalisation that takes place. Nevertheless, the renormalised stress tensor for a conformally invariant field theory acquires a nonzero trace which is independent of the renormalisation ansatz used and which has a value in agreement with that obtained by other methods. A comparison is made with some earlier work using dimensional regularisation which is shown to be in error. (author)
A semi-analytical three-dimensional free vibration analysis of functionally graded curved panels
Energy Technology Data Exchange (ETDEWEB)
Zahedinejad, P. [Department of Mechanical Engineering, Islamic Azad University, Branch of Shiraz, Shiraz (Iran, Islamic Republic of); Malekzadeh, P., E-mail: malekzadeh@pgu.ac.i [Department of Mechanical Engineering, Persian Gulf University, Persian Gulf University Boulevard, Bushehr 75168 (Iran, Islamic Republic of); Center of Excellence for Computational Mechanics, Shiraz University, Shiraz (Iran, Islamic Republic of); Farid, M. [Department of Mechanical Engineering, Islamic Azad University, Branch of Shiraz, Shiraz (Iran, Islamic Republic of); Karami, G. [Department of Mechanical Engineering and Applied Mechanics, North Dakota State University, Fargo, ND 58105-5285 (United States)
2010-08-15
Based on the three-dimensional elasticity theory, free vibration analysis of functionally graded (FG) curved thick panels under various boundary conditions is studied. Panel with two opposite edges simply supported and arbitrary boundary conditions at the other edges are considered. Two different models of material properties variations based on the power law distribution in terms of the volume fractions of the constituents and the exponential distribution of the material properties through the thickness are considered. Differential quadrature method in conjunction with the trigonometric functions is used to discretize the governing equations. With a continuous material properties variation assumption through the thickness of the curved panel, differential quadrature method is efficiently used to discretize the governing equations and to implement the related boundary conditions at the top and bottom surfaces of the curved panel and in strong form. The convergence of the method is demonstrated and to validate the results, comparisons are made with the solutions for isotropic and FG curved panels. By examining the results of thick FG curved panels for various geometrical and material parameters and subjected to different boundary conditions, the influence of these parameters and in particular, those due to functionally graded material parameters are studied.
Hung, Nguyen T.; Nugraha, Ahmad R. T.; Saito, Riichiro
2018-02-01
This paper is a contribution to the Physical Review Applied collection in memory of Mildred S. Dresselhaus. Analytical formulas for thermoelectric figures of merit and power factors are derived based on the one-band model. We find that there is a direct relationship between the optimum figures of merit and the optimum power factors of semiconductors despite of the fact that the two quantities are generally given by different values of chemical potentials. By introducing a dimensionless parameter consisting of the optimum power factor and lattice thermal conductivity (without electronic thermal conductivity), it is possible to unify optimum figures of merit of both bulk and low-dimensional semiconductors into a single universal curve that covers many materials with different dimensionalities.
Park, Young-Seok; Chang, Mi-Sook; Lee, Seung-Pyo
2011-01-01
This study attempted to establish three-dimensional average curves of the gingival line of maxillary teeth using reconstructed virtual models to utilize as guides for dental implant restorations. Virtual models from 100 full-mouth dental stone cast sets were prepared with a three-dimensional scanner and special reconstruction software. Marginal gingival lines were defined by transforming the boundary points to the NURBS (nonuniform rational B-spline) curve. Using an iterative closest point algorithm, the sample models were aligned and the gingival curves were isolated. Each curve was tessellated by 200 points using a uniform interval. The 200 tessellated points of each sample model were averaged according to the index of each model. In a pilot experiment, regression and fitting analysis of one obtained average curve was performed to depict it as mathematical formulae. The three-dimensional average curves of six maxillary anterior teeth, two maxillary right premolars, and a maxillary right first molar were obtained, and their dimensions were measured. Average curves of the gingival lines of young people were investigated. It is proposed that dentists apply these data to implant platforms or abutment designs to achieve ideal esthetics. The curves obtained in the present study may be incorporated as a basis for implant component design to improve the biologic nature and related esthetics of restorations.
Bi-Hamiltonian operators, integrable flows of curves using moving frames and geometric map equations
International Nuclear Information System (INIS)
Anco, Stephen C
2006-01-01
Moving frames of various kinds are used to derive bi-Hamiltonian operators and associated hierarchies of multi-component soliton equations from group-invariant flows of non-stretching curves in constant-curvature manifolds and Lie-group manifolds. The hierarchy in the constant-curvature case consists of a vector mKdV equation coming from a parallel frame, a vector potential mKdV equation coming from a covariantly constant frame, and higher order counterparts generated by an underlying vector mKdV recursion operator. In the Lie-group case, the hierarchy comprises a group-invariant analogue of the vector NLS equation coming from a left-invariant frame, along with higher order counterparts generated by a recursion operator that is like a square root of the mKdV one. The corresponding respective curve flows are found to be given by geometric nonlinear PDEs, specifically mKdV and group-invariant analogues of Schroedinger maps. In all cases the hierarchies also contain variants of vector sine-Gordon equations arising from the kernel of the respective recursion operators. The geometric PDEs that describe the corresponding curve flows are shown to be wave maps
Bi-Hamiltonian operators, integrable flows of curves using moving frames and geometric map equations
Energy Technology Data Exchange (ETDEWEB)
Anco, Stephen C [Department of Mathematics, Brock University, St Catharines, ON (Canada)
2006-03-03
Moving frames of various kinds are used to derive bi-Hamiltonian operators and associated hierarchies of multi-component soliton equations from group-invariant flows of non-stretching curves in constant-curvature manifolds and Lie-group manifolds. The hierarchy in the constant-curvature case consists of a vector mKdV equation coming from a parallel frame, a vector potential mKdV equation coming from a covariantly constant frame, and higher order counterparts generated by an underlying vector mKdV recursion operator. In the Lie-group case, the hierarchy comprises a group-invariant analogue of the vector NLS equation coming from a left-invariant frame, along with higher order counterparts generated by a recursion operator that is like a square root of the mKdV one. The corresponding respective curve flows are found to be given by geometric nonlinear PDEs, specifically mKdV and group-invariant analogues of Schroedinger maps. In all cases the hierarchies also contain variants of vector sine-Gordon equations arising from the kernel of the respective recursion operators. The geometric PDEs that describe the corresponding curve flows are shown to be wave maps.
International Nuclear Information System (INIS)
Hayashi, Tetsuji; Tsuzuki, Satoshi; Tsunewaki, Hiroshi.
1993-01-01
A 6-axis portable manipulator, weighing 120 N (12.3 kg) which traces over a 3-dimensional curved surface for ultrasonic testing has been developed. The manipulator body is made of carbon-fiber-reinforced plastic and magnesium alloy. A feature of the system is that deviation of the manipulator from its nominal path caused by arm bending due to its own weight can be corrected. The deviation is calculated by premeasuring spring coefficients and hysteresis characteristics of the arm structure. In a mock-up calibration performance test the accuracy was shown to be as high as that of a human inspector. The manipulator can be installed within 3 minutes by a single person. Joint angles are calculated with a direct memory access (DMA) handler using a poling method. Signals are transmitted to servo-controllers through an optical fiber of 2.5 Mbps. (author)
Three-dimensional charge dispersion curves from interactions of 11--29 GeV protons with uranium
International Nuclear Information System (INIS)
Yu, Y.
1980-01-01
Experimental nuclear charge dispersion curves from interactions of 11--29 Gev protons with 238 U have been used in the construction of three-dimensional charge dispersion curves. They show the yield variation with mass number A. Neutron-deficient products are distributed over the entire mass range with a peak at A near 87, while the yield of neutron-excessive products is distributed only in the relatively narrow mass region between A=70 and A=150 and has a maximum around A=115. An isobaric yield curve has been obtained by summing up each of the charge dispersion curves and shows a peak, rather than the flat top, in the mass region A=80 to 140 reported previously. The mass yield curves of neutron-excessive and neutron-deficient products are obtained by a decomposition of the charge dispersion curve with two Gaussians, and the mechanism of formation is suggested
One-dimensional field theories with odd-power self-interactions
International Nuclear Information System (INIS)
Fullin, W.C.
1978-01-01
Classical solutions to nonlinear field theories are considered as model particles. Two fields are examined here, the lambdaphi 3 field and a generalization of the sine-Gordon system. Each of these fields is in one space dimension and quantization is accomplished using the WKB method. Static solutions to the lambdaphi 3 field are shown to represent objects with an internal structure resembling a dumbbell. The quantum mass of these objects is computed in the weak-coupling limit and an approximate expression for the classical force between two of these objects is obtained. This force seems to be attractive and constant at large separations. In the case of the generalized sine-Gordon field it is shown that classical solutions to the field equation may be obtained by a transformation from known solutions to the sine-Gordon equation. The behavior of this field is therefore similar to that of the sine-Gordon field
Closed loop engine control for regulating NOx emissions, using a two-dimensional fuel-air curve
Bourn, Gary D.; Smith, Jack A.; Gingrich, Jess W.
2007-01-30
An engine control strategy that ensures that NOx emissions from the engine will be maintained at an acceptable level. The control strategy is based on a two-dimensional fuel-air curve, in which air manifold pressure (AMP) is a function of fuel header pressure and engine speed. The control strategy provides for closed loop NOx adjustment to a base AMP value derived from the fuel-air curve.
Maximal superintegrability of the generalized Kepler-Coulomb system on N-dimensional curved spaces
International Nuclear Information System (INIS)
Ballesteros, Angel; Herranz, Francisco J
2009-01-01
The superposition of the Kepler-Coulomb potential on the 3D Euclidean space with three centrifugal terms has recently been shown to be maximally superintegrable (Verrier and Evans 2008 J. Math. Phys. 49 022902) by finding an additional (hidden) integral of motion which is quartic in the momenta. In this paper, we present the generalization of this result to the N-dimensional spherical, hyperbolic and Euclidean spaces by making use of a unified symmetry approach that makes use of the curvature parameter. The resulting Hamiltonian, formed by the (curved) Kepler-Coulomb potential together with N centrifugal terms, is shown to be endowed with 2N - 1 functionally independent integrals of the motion: one of them is quartic and the remaining ones are quadratic. The transition from the proper Kepler-Coulomb potential, with its associated quadratic Laplace-Runge-Lenz N-vector, to the generalized system is fully described. The role of spherical, nonlinear (cubic) and coalgebra symmetries in all these systems is highlighted
Three dimensional range geometry and texture data compression with space-filling curves.
Chen, Xia; Zhang, Song
2017-10-16
This paper presents a novel method to effectively store three-dimensional (3D) data and 2D texture data into a regular 24-bit image. The proposed method uses the Hilbert space-filling curve to map the normalized unwrapped phase map to two 8-bit color channels, and saves the third color channel for 2D texture storage. By further leveraging existing 2D image and video compression techniques, the proposed method can achieve high compression ratios while effectively preserving data quality. Since the encoding and decoding processes can be applied to most of the current 2D media platforms, this proposed compression method can make 3D data storage and transmission available for many electrical devices without requiring special hardware changes. Experiments demonstrate that if a lossless 2D image/video format is used, both original 3D geometry and 2D color texture can be accurately recovered; if lossy image/video compression is used, only black-and-white or grayscale texture can be properly recovered, but much higher compression ratios (e.g., 1543:1 against the ASCII OBJ format) are achieved with slight loss of 3D geometry quality.
Meiners, LC; Scheffers, JM; De Kort, GAP; Burger, H; Van Huffelen, AC; Van Rijen, PC; Van Veelen, CWM
RATIONALE AND OBJECTIVES. TO compare the visibility and localization of extratemporal cortical lesions in extratemporal epilepsy by using curved reconstruction (CR) and three-dimensional surface rendering (3D SR) of 3D-acquired MR images and to study the degree of confidence with which localizations
Directory of Open Access Journals (Sweden)
Li Xiaoying
2015-09-01
Full Text Available This paper introduces a knitting technique for making innovative curved three-dimensional (3D spacer fabrics by the computer flat-knitting machine. During manufacturing, a number of reinforcement yarns made of aramid fibres are inserted into 3D spacer fabrics along the weft direction to enhance the fabric tensile properties. Curved, flat-knitted 3D spacer fabrics with different angles (in the warp direction were also developed. Tensile tests were carried out in the weft and warp directions for the two spacer fabrics (with and without reinforcement yarns, and their stress–strain curves were compared. The results showed that the reinforcement yarns can reduce the fabric deformation and improve tensile stress and dimensional stability of 3D spacer fabrics. This research can help the further study of 3D spacer fabric when applied to composites.
Quantum restoration of broken symmetry in onedimensional loop ...
Indian Academy of Sciences (India)
Home; Journals; Pramana – Journal of Physics; Volume 82; Issue 6. Quantum restoration of broken symmetry in ... Keywords. Non-local transformation; broken symmetry; sine-Gordon; sech interaction. ... A specific type of classically broken symmetry is restored in quantum theory. One-dimensional sine-Gordon system and ...
Nonlinear Dynamic of Curved Railway Tracks in Three-Dimensional Space
Liu, X.; Ngamkhanong, C.; Kaewunruen, S.
2017-12-01
On curved tracks, high-pitch noise pollution can often be a considerable concern of rail asset owners, commuters, and people living or working along the rail corridor. Inevitably, wheel/rail interface can cause a traveling source of sound and vibration, which spread over a long distance of rail network. The sound and vibration can be in various forms and spectra. The undesirable sound and vibration on curves is often called ‘noise,’ includes flanging and squealing noises. This paper focuses on the squeal noise phenomena on curved tracks located in urban environments. It highlights the effect of curve radii on lateral track dynamics. It is important to note that rail freight curve noises, especially for curve squeals, can be observed almost everywhere and every type of track structures. The most pressing noise appears at sharper curved tracks where excessive lateral wheel/rail dynamics resonate with falling friction states, generating a tonal noise problem, so-call ‘squeal’. Many researchers have carried out measurements and simulations to understand the actual root causes of the squeal noise. Most researchers believe that wheel resonance over falling friction is the main cause, whilst a few others think that dynamic mode coupling of wheel and rail may also cause the squeal. Therefore, this paper is devoted to systems thinking the approach and dynamic assessment in resolving railway curve noise problems. The simulations of railway tracks with different curve radii will be carried out to develop state-of-the-art understanding into lateral track dynamics, including rail dynamics, cant dynamics, gauge dynamics and overall track responses.
International Nuclear Information System (INIS)
Moon, Myung-Kook; Lee, Chang-Hee; Kim, Shin-Ae; Noda, Yukio
2013-01-01
A new type of two-dimensional curved position-sensitive neutron detector has been developed for a high-throughput single-crystal neutron diffractometer, which was designed to cover 110° horizontally and 56° vertically. The prototype curved detector covering 70° horizontally and 45° vertically was first developed to test the technical feasibility of the detector parameters, the internal anode and cathode structures for the curved shape, technical difficulties in the assembly procedure, and so on. Then, based on this experience, a full-scale curved detector with twice the active area of the prototype was fabricated with newly modified anode and cathode planes and optimized design parameters in terms of mechanical and electric properties. The detector was installed in a dedicated diffractometer at the ST3 beam port of the research reactor HANARO. In this paper, the fabrication and application of the prototype and a new larger-area curved position-sensitive neutron detector for single crystal diffraction is presented
Yushin, Gleb; Evanoff, Kara; Magasinski, Alexander
2012-01-01
Thin Si films coated on porous 3D particles composed of curved 2D graphene sheets have been synthesized utilizing techniques that allow for tunable properties. Since graphene exhibits specific surface area up to 100 times higher than carbon black or graphite, the deposition of the same mass of Si on graphene is much faster in comparison -- a factor which is important for practical applications. In addition, the distance between graphene layers is tunable and variation in the thickness of the deposited Si film is feasible. Both of these characteristics allow for optimization of the energy and power characteristics. Thicker films will allow higher capacity, but slower rate capabilities. Thinner films will allow more rapid charging, or higher power performance. In this innovation, uniform deposition of Si and C layers on high-surface area graphene produced granules with specific surface area (SSA) of 5 sq. m/g.
Use of the Master Curve methodology for real three dimensional cracks
International Nuclear Information System (INIS)
Wallin, Kim
2007-01-01
At VTT, development work has been in progress for 15 years to develop and validate testing and analysis methods applicable for fracture resistance determination from small material samples. The VTT approach is a holistic approach by which to determine static, dynamic and crack arrest fracture toughness properties either directly or by correlations from small material samples. The development work has evolved a testing standard for fracture toughness testing in the transition region. The standard, known as the Master Curve standard is in a way 'first of a kind', since it includes guidelines on how to properly treat the test data for use in structural integrity assessment. No standard, so far, has done this. The standard is based on the VTT approach, but presently, the VTT approach goes beyond the standard. Key components in the standard are statistical expressions for describing the data scatter, and for predicting a specimens size (crack front length) effect and an expression (Master Curve) for the fracture toughness temperature dependence. The standard and the approach, it is based upon, can be considered to represent the state of the art of small specimen fracture toughness characterization. Normally, the Master Curve parameters are determined using test specimens with 'straight' crack fronts and comparatively uniform stress state along the crack front. This enables the use of a single K I value and single constraint value to describe the whole specimen. For a real crack in a structure, this is usually not the case. Normally, both K I and constraint vary along the crack front and in the case of a thermal shock, even the temperature will vary along the crack front. A proper means of applying the Master Curve methodology for such cases is presented here
Use of the master curve methodology for real three dimensional cracks
International Nuclear Information System (INIS)
Wallin, K.; Rintamaa, R.
2005-01-01
At VTT, development work has been in progress for 15 years to develop and validate testing and analysis methods applicable for fracture resistance determination from small material samples. The VTT approach is a holistic approach by which to determine static, dynamic and crack arrest fracture toughness properties either directly or by correlations from small material samples. The development work has evolved a testing standard for fracture toughness testing in the transition region. The standard, known as the Master Curve standard is in a way 'first of a kind', since it includes guidelines on how to properly treat the test data for use in structural integrity assessment. No standard, so far, has done this. The standard is based on the VTT approach, but presently, the VTT approach goes beyond the standard. Key components in the standard are statistical expressions for describing the data scatter, and for predicting a specimen's size (crack front length) effect and an expression (Master Curve) for the fracture toughness temperature dependence. The standard and the approach it is based upon can be considered to represent the state of the art of small specimen fracture toughness characterization. Normally, the Master Curve parameters are determined using test specimens with 'straight' crack fronts and comparatively uniform stress state along the crack front. This enables the use of a single KI value and single constraint value to describe the whole specimen. For a real crack in a structure, this is usually not the case. Normally, both KI and constraint varies along the crack front and in the case of a thermal shock, even the temperature will vary along the crack front. A proper means of applying the Master Curve methodology for such cases is presented here. (authors)
Two-dimensional thermofield bosonization II: Massive fermions
International Nuclear Information System (INIS)
Amaral, R.L.P.G.; Belvedere, L.V.; Rothe, K.D.
2008-01-01
We consider the perturbative computation of the N-point function of chiral densities of massive free fermions at finite temperature within the thermofield dynamics approach. The infinite series in the mass parameter for the N-point functions are computed in the fermionic formulation and compared with the corresponding perturbative series in the interaction parameter in the bosonized thermofield formulation. Thereby we establish in thermofield dynamics the formal equivalence of the massive free fermion theory with the sine-Gordon thermofield model for a particular value of the sine-Gordon parameter. We extend the thermofield bosonization to include the massive Thirring model
Three-dimensional numerical modeling of turbulent single-phase and two-phase flow in curved pipes
International Nuclear Information System (INIS)
Xin, R.C.; Dong, Z.F.; Ebadian, M.A.
1996-01-01
In this study, three-dimensional single-phase and two-phase flows in curved pipes have been investigated numerically. Two different pipe configurations were computed. When the results of the single-phase flow simulation were compared with the experimental data, a fairly good agreement was achieved. A flow-developing process has been suggested in single-phase flow, in which the turbulence is stronger near the outer tube wall than near the inner tube wall. For two-phase flow, the Eulerian multiphase model was used to simulate the phase distribution of a three-dimensional gas-liquid bubble flow in curved pipe. The RNG/κ-ε turbulence model was used to determine the turbulence field. An inlet gas void fraction of 5 percent was simulated. The gas phase effects on the liquid phase flow velocity have been examined by comparing the results of single-phase flow and two-phase flow. The findings show that for the downward flow in the U bend, the gas concentrates at the inner portion of the cross section at φ = π/18 - π/6 in most cases. The results of the phase distribution simulation are compared to experimental observations qualitatively and topologically
Dirac equation in 2-dimensional curved spacetime, particle creation, and coupled waveguide arrays
Energy Technology Data Exchange (ETDEWEB)
Koke, Christian, E-mail: christian.koke@stud.uni-heidelberg.de [Institut für theoretische Physik, Philosophenweg 16, D-69120 Heidelberg (Germany); Noh, Changsuk, E-mail: changsuk@kias.re.kr [Korea Institute for Advanced Study, 85 Hoegiro, Seoul 130-722 (Korea, Republic of); Angelakis, Dimitris G., E-mail: dimitris.angelakis@gmail.com [Centre for Quantum Technologies, National University of Singapore, 2 Science Drive 3, 117542 (Singapore); School of Electronic and Computer Engineering, Technical University of Crete, Chania, Crete, 73100 (Greece)
2016-11-15
When quantum fields are coupled to gravitational fields, spontaneous particle creation may occur similarly to when they are coupled to external electromagnetic fields. A gravitational field can be incorporated as a background spacetime if the back-action of matter on the field can be neglected, resulting in modifications of the Dirac or Klein–Gordon equations for elementary fermions and bosons respectively. The semi-classical description predicts particle creation in many situations, including the expanding-universe scenario, near the event horizon of a black hole (the Hawking effect), and an accelerating observer in flat spacetime (the Unruh effect). In this work, we give a pedagogical introduction to the Dirac equation in a general 2D spacetime and show examples of spinor wave packet dynamics in flat and curved background spacetimes. In particular, we cover the phenomenon of particle creation in a time-dependent metric. Photonic analogs of these effects are then proposed, where classical light propagating in an array of coupled waveguides provides a visualisation of the Dirac spinor propagating in a curved 2D spacetime background. The extent to which such a single-particle description can be said to mimic particle creation is discussed.
Finite element method for one-dimensional rill erosion simulation on a curved slope
Directory of Open Access Journals (Sweden)
Lijuan Yan
2015-03-01
Full Text Available Rill erosion models are important to hillslope soil erosion prediction and to land use planning. The development of rill erosion models and their use has become increasingly of great concern. The purpose of this research was to develop mathematic models with computer simulation procedures to simulate and predict rill erosion. The finite element method is known as an efficient tool in many other applications than in rill soil erosion. In this study, the hydrodynamic and sediment continuity model equations for a rill erosion system were solved by the Galerkin finite element method and Visual C++ procedures. The simulated results are compared with the data for spatially and temporally measured processes for rill erosion under different conditions. The results indicate that the one-dimensional linear finite element method produced excellent predictions of rill erosion processes. Therefore, this study supplies a tool for further development of a dynamic soil erosion prediction model.
Magneto-transport studies on curved two-dimensional electron gases in InGaAs-microscrolls
International Nuclear Information System (INIS)
Schumacher, O.
2007-01-01
In this thesis magneto-resistance studies on evenly curved two-dimensional electron systems in cylindric geometry are presented and discussed. A principle first introduced by Prinz and co-workers in 1998 enables us to roll up thin semiconductor layer systems by taking advantage of internal elastic strain. The radius of such a semiconductor tube can be adjusted ranging from a few nanometers up to several micrometers. The tubes' shape and place on the substrate can be defined by lithographic methods which are presented in this work. Furthermore, we show rolled-up structures containing a two-dimensional electron system in the tube wall. With a special lithographic procedure we are able to structure, to contact and to roll up these 2D-electron-gases in Hall geometry. As a result, a cylindric two-dimensional electron system is produced, which experiences a modulation of the perpendicular magnetic field component. The radius of curvature of our structures is about 10 μm, the carrier mobility is optimized to values up to 125,000 cm 2 /Vs. In transport experiments on curved Hall bars containing two dimensional electron systems two Hall bar orientations, with respect to the curvature, may be distinguished. In this work both orientations, i.e. with a Hall bar along the tube curvature as well as a Hall bar along the tube axis, are presented and discussed. Measurements on Hall bars along the curvature show signatures in the longitudinal resistance, which can be understood with the help of the Landauer-Buettiker-formalism and the model of magnetic barriers. For Hall bars oriented along the tube axis the perpendicular magnetic field component averaged over the width of the bar defines the minimum position of the Shubnikov-de Haas-oscillations as well as the slope of the Hall resistance. Furthermore, measurements on so-called van the Pauw-lamellas are presented. In this geometry the magneto-resistance shows a slope which refers to highly mobile conditions at the zero crossing of
Wang, Yong-Long; Jiang, Hua; Zong, Hong-Shi
2017-08-01
In the spirit of the thin-layer quantization approach, we give the formula of the geometric influences of a particle confined to a curved surface embedded in three-dimensional Euclidean space. The geometric contributions can result from the reduced commutation relation between the acted function depending on normal variable and the normal derivative. According to the formula, we obtain the geometric potential, geometric momentum, geometric orbital angular momentum, geometric linear Rashba, and cubic Dresselhaus spin-orbit couplings. As an example, a truncated cone surface is considered. We find that the geometric orbital angular momentum can provide an azimuthal polarization for spin, and the sign of the geometric Dresselhaus spin-orbit coupling can be flipped through the inclination angle of generatrix.
Padin, Esther Mariño; Santos, Raquel Sánchez; Fernández, Sonia González; Jimenez, Antonia Brox; Fernández, Sergio Estevez; Dacosta, Ester Carrera; Duran, Agata Rial; Artime Rial, Maria; Dominguez Sanchez, Ivan
2017-10-01
3D laparoscopy allows the surgeon to regain the sense of depth and improve accuracy. The aim of the study was to assess the impact of 3D in bariatric surgery. A retrospective cohort study was conducted. All our patients who underwent bariatric surgery (sleeve gastrectomy (SG) or gastric bypass (GB)) between 2013 and 2016 were included. We compared 3D laparoscopy cohort and 2D laparoscopy cohort. Variables are as follows: age, sex, DM, hypertension, surgeon experience, and type of intervention. Comparisons of operative time, hospital stay, conversion, complications, reoperation, and exitus are completed. Three hundred twelve consecutive patients were included. 56.9% of patients underwent GB and 43.1% SG. Global complications were 3.2% (fistula 2.5%, hemoperitoneum 0.3%, others 0.4%). One hundred four procedures were performed in the 3D cohort and 208 in the 2D cohort. The 2D cohort and 3D cohort were similar regarding the following: percentage of GB vs SG, age, gender, learning curve, diabetes mellitus 2, hypertension, and sleep apnea. The operating time and hospital stay were significantly reduced in the 3D cohort (144.07 ± 58.07 vs 172.11 ± 76.11 min and 5.12 ± 9.6 vs 7.7 ± 13.2 days. It was the same when we stratified the sample by type of surgery or experience of the surgeon. Complications were reduced in the 3D cohort in the surgeries performed by novice surgeons (10.2 vs 1.8%, p = 0.034). The use of 3D laparoscopy in bariatric surgery in our center has helped reducing the operating time and hospital stay, and improving the safety of the surgery, either in GB or SG, being equally favorable in novice or more experienced surgeons.
International Nuclear Information System (INIS)
Guo, En Min; Kim, Kwang Yong
2004-01-01
This work developed improved slip factor model and correction method to predict flow through impeller in forward-curved centrifugal fan. Both steady and unsteady three-dimensional CFD analyses were performed to validate the slip factor model and the correction method. The results show that the improved slip factor model presented in this paper could provide more accurate predictions for forward-curved centrifugal impeller than the other slip factor models since the present model takes into account the effect of blade curvature. The correction method is provided to predict mass-averaged absolute circumferential velocity at the exit of impeller by taking account of blockage effects induced by the large-scale backflow near the front plate and flow separation within blade passage. The comparison with CFD results also shows that the improved slip factor model coupled with the present correction method provides accurate predictions for mass-averaged absolute circumferential velocity at the exit of impeller near and above the flow rate of peak total pressure coefficient
International Nuclear Information System (INIS)
Duwel, A.E.; Watanabe, S.; Trias, E.; Orlando, T.P.; van der Zant, H.S.; Strogatz, S.H.
1997-01-01
New resonance steps are found in the experimental current-voltage characteristics of long, discrete, one-dimensional Josephson junction arrays with open boundaries and in an external magnetic field. The junctions are underdamped, connected in parallel, and dc biased. Numerical simulations based on the discrete sine-Gordon model are carried out, and show that the solutions on the steps are periodic trains of fluxons, phase locked by a finite amplitude radiation. Power spectra of the voltages consist of a small number of harmonic peaks, which may be exploited for possible oscillator applications. The steps form a family that can be numbered by the harmonic content of the radiation, the first member corresponding to the Eck step. Discreteness of the arrays is shown to be essential for appearance of the higher order steps. We use a multimode extension of the harmonic balance analysis, and estimate the resonance frequencies, the ac voltage amplitudes, and the theoretical limit on the output power on the first two steps. copyright 1997 American Institute of Physics
Exactly solvable model of the two-dimensional electrical double layer.
Samaj, L; Bajnok, Z
2005-12-01
We consider equilibrium statistical mechanics of a simplified model for the ideal conductor electrode in an interface contact with a classical semi-infinite electrolyte, modeled by the two-dimensional Coulomb gas of pointlike unit charges in the stability-against-collapse regime of reduced inverse temperatures 0layer) carries some nonzero surface charge density. The model is mappable onto an integrable semi-infinite sine-Gordon theory with Dirichlet boundary conditions. The exact form-factor and boundary state information gained from the mapping provide asymptotic forms of the charge and number density profiles of electrolyte particles at large distances from the interface. The result for the asymptotic behavior of the induced electric potential, related to the charge density via the Poisson equation, confirms the validity of the concept of renormalized charge and the corresponding saturation hypothesis. It is documented on the nonperturbative result for the asymptotic density profile at a strictly nonzero beta that the Debye-Hückel beta-->0 limit is a delicate issue.
de Godoy, Luiz Antonio Fonseca; Hantao, Leandro Wang; Pedroso, Marcio Pozzobon; Poppi, Ronei Jesus; Augusto, Fabio
2011-08-05
The use of multivariate curve resolution (MCR) to build multivariate quantitative models using data obtained from comprehensive two-dimensional gas chromatography with flame ionization detection (GC×GC-FID) is presented and evaluated. The MCR algorithm presents some important features, such as second order advantage and the recovery of the instrumental response for each pure component after optimization by an alternating least squares (ALS) procedure. A model to quantify the essential oil of rosemary was built using a calibration set containing only known concentrations of the essential oil and cereal alcohol as solvent. A calibration curve correlating the concentration of the essential oil of rosemary and the instrumental response obtained from the MCR-ALS algorithm was obtained, and this calibration model was applied to predict the concentration of the oil in complex samples (mixtures of the essential oil, pineapple essence and commercial perfume). The values of the root mean square error of prediction (RMSEP) and of the root mean square error of the percentage deviation (RMSPD) obtained were 0.4% (v/v) and 7.2%, respectively. Additionally, a second model was built and used to evaluate the accuracy of the method. A model to quantify the essential oil of lemon grass was built and its concentration was predicted in the validation set and real perfume samples. The RMSEP and RMSPD obtained were 0.5% (v/v) and 6.9%, respectively, and the concentration of the essential oil of lemon grass in perfume agreed to the value informed by the manufacturer. The result indicates that the MCR algorithm is adequate to resolve the target chromatogram from the complex sample and to build multivariate models of GC×GC-FID data. Copyright © 2011 Elsevier B.V. All rights reserved.
International Nuclear Information System (INIS)
Pandey, Pradeep; Nayak, A.K.; Vijayan, P.K.
2014-01-01
Three dimensional flow patterns appearing in geometries such as curved pipes and T-channel junctions have important applications and are attractive for research. Unlike the flow in a straight tube, fluid motion in a curved tube is not parallel to the axis of bend, owing to the presence of centrifugal effects. It is characterized by a secondary flow in a cross-sectional plane normal to the main flow. Consequently, secondary flow separation near the inner wall is observed in the developing region. The strength of the secondary flow is greatly influenced by the curvature ratio and in turn, a non-dimensional parameter called the Dean Number. Secondary flow increases flow resistance, resulting in a larger pressure drop along the bend. The location of the maximum axial velocity gets shifted towards the outer wall. Flow in a T-channel junction is also a configuration of great significance. The simulations of the present work show that flow at low Reynolds numbers (Re ≤ 115) is steady and symmetric. For low Reynolds numbers, flow in the downstream channel remains highly segregated about the centerline. The appearance of vortices in the T-channel junction does little to redistribute concentration when flow remains symmetric. With increasing Reynolds number, transition takes place towards asymmetric flow. The incoming flow field gets redistributed at the center-plane and the dividing streamline becomes increasingly distorted. The flow field is characterized by thin elongated fluid interfaces across which momentum diffusion takes place. Flow at higher Reynolds numbers (Re ≥ 250) becomes unsteady in which unstable stagnation stream traces move periodically leftward and rightward at top and bottom walls. Trajectories of mass-less particles show greater dwelling in the junction as compared to those of finite mass particle. The numerical simulation is carried out in the present work using ANUPRAVAHA, a general purpose CFD solver developed at IIT Kanpur in collaboration with
Energy Technology Data Exchange (ETDEWEB)
Chhipa, Mayur Kumar, E-mail: mayurchhipa1@gmail.com [Deptt. of Electronics and Communication Engineering, Government Engineering College Ajmer Rajasthan INDIA (India); Dusad, Lalit Kumar [Rajasthan Technical University Kota, Rajasthan (India)
2016-05-06
In this paper channel drop filter (CDF) is designed using dual curved photonic crystal ring resonator (PCRR). The photonic band gap (PBG) is calculated by plane wave expansion (PWE) method and the photonic crystal (PhC) based on two dimensional (2D) square lattice periodic arrays of silicon (Si) rods in air structure have been investigated using finite difference time domain (FDTD) method. The number of rods in Z and X directions is 21 and 20 respectively with lattice constant 0.540 nm and rod radius r = 0.1 µm. The channel drop filter has been optimized for telecommunication wavelengths λ = 1.591 µm with refractive indices 3.533. In the designed structure further analysis is also done by changing whole rods refractive index and it has been observed that this filter may be used for filtering several other channels also. The designed structure is useful for CWDM systems. This device may serve as a key component in photonic integrated circuits. The device is ultra compact with the overall size around 123 µm{sup 2}.
Somoskeöy, Szabolcs; Tunyogi-Csapó, Miklós; Bogyó, Csaba; Illés, Tamás
2012-10-01
For many decades, visualization and evaluation of three-dimensional (3D) spinal deformities have only been possible by two-dimensional (2D) radiodiagnostic methods, and as a result, characterization and classification were based on 2D terminologies. Recent developments in medical digital imaging and 3D visualization techniques including surface 3D reconstructions opened a chance for a long-sought change in this field. Supported by a 3D Terminology on Spinal Deformities of the Scoliosis Research Society, an approach for 3D measurements and a new 3D classification of scoliosis yielded several compelling concepts on 3D visualization and new proposals for 3D classification in recent years. More recently, a new proposal for visualization and complete 3D evaluation of the spine by 3D vertebra vectors has been introduced by our workgroup, a concept, based on EOS 2D/3D, a groundbreaking new ultralow radiation dose integrated orthopedic imaging device with sterEOS 3D spine reconstruction software. Comparison of accuracy, correlation of measurement values, intraobserver and interrater reliability of methods by conventional manual 2D and vertebra vector-based 3D measurements in a routine clinical setting. Retrospective, nonrandomized study of diagnostic X-ray images created as part of a routine clinical protocol of eligible patients examined at our clinic during a 30-month period between July 2007 and December 2009. In total, 201 individuals (170 females, 31 males; mean age, 19.88 years) including 10 healthy athletes with normal spine and patients with adolescent idiopathic scoliosis (175 cases), adult degenerative scoliosis (11 cases), and Scheuermann hyperkyphosis (5 cases). Overall range of coronal curves was between 2.4 and 117.5°. Analysis of accuracy and reliability of measurements was carried out on a group of all patients and in subgroups based on coronal plane deviation: 0 to 10° (Group 1; n=36), 10 to 25° (Group 2; n=25), 25 to 50° (Group 3; n=69), 50 to 75
New developments in the theoretical treatment of low dimensional strongly correlated systems.
James, Andrew J A; Konik, Robert M; Lecheminant, Philippe; Robinson, Neil; Tsvelik, Alexei M
2017-10-09
We review two important non-perturbative approaches for extracting the physics of low- dimensional strongly correlated quantum systems. Firstly, we start by providing a comprehensive review of non-Abelian bosonization. This includes an introduction to the basic elements of confor- mal field theory as applied to systems with a current algebra, and we orient the reader by presenting a number of applications of non-Abelian bosonization to models with large symmetries. We then tie this technique into recent advances in the ability of cold atomic systems to realize complex symme- tries. Secondly, we discuss truncated spectrum methods for the numerical study of systems in one and two dimensions. For one-dimensional systems we provide the reader with considerable insight into the methodology by reviewing canonical applications of the technique to the Ising model (and its variants) and the sine-Gordon model. Following this we review recent work on the development of renormalization groups, both numerical and analytical, that alleviate the effects of truncating the spectrum. Using these technologies, we consider a number of applications to one-dimensional systems: properties of carbon nanotubes, quenches in the Lieb-Liniger model, 1+1D quantum chro- modynamics, as well as Landau-Ginzburg theories. In the final part we move our attention to consider truncated spectrum methods applied to two-dimensional systems. This involves combining truncated spectrum methods with matrix product state algorithms. We describe applications of this method to two-dimensional systems of free fermions and the quantum Ising model, including their non-equilibrium dynamics. © 2017 IOP Publishing Ltd.
Chovalopoulou, Maria-Eleni; Valakos, Efstratios D; Manolis, Sotiris K
2016-06-01
The aim of this study is to assess sexual dimorphism of adult crania in the vault and midsagittal curve of the vault using three-dimensional geometric morphometric methods. The study sample consisted of 176 crania of known sex (94 males, 82 females) belonging to individuals who lived during the 20th century in Greece. The three-dimensional co-ordinates of 31 ecto-cranial landmarks and 30 semi-landmarks were digitized using a MicroScribe 3DX contact digitizer. Generalized Procrustes analysis (GPA) was used to obtain size and shape variables for statistical analysis. Shape, size and form analyses were carried out by logistic regression and three discriminant function analyses. Results indicate that there are shape differences between sexes. Females in the region of the parietal bones are narrower and the axis forming the frontal and occipital bones is more elongated; the frontal bone is more vertical. Sex-specific shape differences give better classification results in the vault (79%) compared with the midsagittal curve of the neurocranium (68.8%). Size alone yielded better results for cranial vault (82%), while for the midsagittal curve of the vault the result is poorer (68.1%). As anticipated, the classification accuracy improves when both size and shape are combined (89.2% for vault, and 79.4% for midsagittal curve of the vault). These latter findings imply that, in contrast to the midsagittal curve of the neurocranium, the shape of the cranial vault can be used as an indicator of sex in the modern Greek population. Copyright © 2016. Published by Elsevier GmbH.
Directory of Open Access Journals (Sweden)
Zeyu Liu
2018-01-01
Full Text Available A new fractional two-dimensional triangle function combination discrete chaotic map (2D-TFCDM with the discrete fractional difference is proposed. We observe the bifurcation behaviors and draw the bifurcation diagrams, the largest Lyapunov exponent plot, and the phase portraits of the proposed map, respectively. On the application side, we apply the proposed discrete fractional map into image encryption with the secret keys ciphered by Menezes-Vanstone Elliptic Curve Cryptosystem (MVECC. Finally, the image encryption algorithm is analysed in four main aspects that indicate the proposed algorithm is better than others.
International Nuclear Information System (INIS)
Faria da Veiga, Paulo A.; O’Carroll, Michael; Valencia Alvites, José C.
2016-01-01
Considering a 3 + 1 dimensional lattice quantum chromodynamics (QCD) model defined with the improved Wilson action, three flavors, and 4 × 4 Dirac spin matrices, in the strong coupling regime, we reanalyze the question of the existence of the eightfold way baryons and complete our previous work where the existence of isospin octet baryons was rigorously solved. Here, we show the existence of isospin decuplet baryons which are associated with isolated dispersion curves in the subspace of the underlying quantum mechanical Hilbert space with vectors constructed with an odd number of fermion and antifermion basic quark and antiquark fields. Moreover, smoothness properties for these curves are obtained. The present work deals with a case for which the traditional method to solve the implicit equation for the dispersion curves, based on the use of the analytic implicit function theorem, cannot be applied. We do not have only one but two solutions for each one-baryon decuplet sector with fixed spin third component. Instead, we apply the Weierstrass preparation theorem, which also provides a general method for the general degenerate case. This work is completed by analyzing a spectral representation for the two-baryon correlations and providing the leading behaviors of the field strength normalization and the mass of the spectral contributions with more than one-particle. These are needed results for a rigorous analysis of the two-baryon and meson-baryon particle spectra.
Energy Technology Data Exchange (ETDEWEB)
Faria da Veiga, Paulo A., E-mail: veiga@icmc.usp.br; O’Carroll, Michael, E-mail: michaelocarroll@gmail.com; Valencia Alvites, José C., E-mail: cien.mat@hotmail.com [Departamento de Matemática Aplicada e Estatística, ICMC, USP-São Carlos, C.P. 668, São Carlos, SP 13560-970 (Brazil)
2016-03-15
Considering a 3 + 1 dimensional lattice quantum chromodynamics (QCD) model defined with the improved Wilson action, three flavors, and 4 × 4 Dirac spin matrices, in the strong coupling regime, we reanalyze the question of the existence of the eightfold way baryons and complete our previous work where the existence of isospin octet baryons was rigorously solved. Here, we show the existence of isospin decuplet baryons which are associated with isolated dispersion curves in the subspace of the underlying quantum mechanical Hilbert space with vectors constructed with an odd number of fermion and antifermion basic quark and antiquark fields. Moreover, smoothness properties for these curves are obtained. The present work deals with a case for which the traditional method to solve the implicit equation for the dispersion curves, based on the use of the analytic implicit function theorem, cannot be applied. We do not have only one but two solutions for each one-baryon decuplet sector with fixed spin third component. Instead, we apply the Weierstrass preparation theorem, which also provides a general method for the general degenerate case. This work is completed by analyzing a spectral representation for the two-baryon correlations and providing the leading behaviors of the field strength normalization and the mass of the spectral contributions with more than one-particle. These are needed results for a rigorous analysis of the two-baryon and meson-baryon particle spectra.
James, Andrew J A; Konik, Robert M; Lecheminant, Philippe; Robinson, Neil J; Tsvelik, Alexei M
2018-02-26
We review two important non-perturbative approaches for extracting the physics of low-dimensional strongly correlated quantum systems. Firstly, we start by providing a comprehensive review of non-Abelian bosonization. This includes an introduction to the basic elements of conformal field theory as applied to systems with a current algebra, and we orient the reader by presenting a number of applications of non-Abelian bosonization to models with large symmetries. We then tie this technique into recent advances in the ability of cold atomic systems to realize complex symmetries. Secondly, we discuss truncated spectrum methods for the numerical study of systems in one and two dimensions. For one-dimensional systems we provide the reader with considerable insight into the methodology by reviewing canonical applications of the technique to the Ising model (and its variants) and the sine-Gordon model. Following this we review recent work on the development of renormalization groups, both numerical and analytical, that alleviate the effects of truncating the spectrum. Using these technologies, we consider a number of applications to one-dimensional systems: properties of carbon nanotubes, quenches in the Lieb-Liniger model, 1 + 1D quantum chromodynamics, as well as Landau-Ginzburg theories. In the final part we move our attention to consider truncated spectrum methods applied to two-dimensional systems. This involves combining truncated spectrum methods with matrix product state algorithms. We describe applications of this method to two-dimensional systems of free fermions and the quantum Ising model, including their non-equilibrium dynamics.
James, Andrew J. A.; Konik, Robert M.; Lecheminant, Philippe; Robinson, Neil J.; Tsvelik, Alexei M.
2018-04-01
We review two important non-perturbative approaches for extracting the physics of low-dimensional strongly correlated quantum systems. Firstly, we start by providing a comprehensive review of non-Abelian bosonization. This includes an introduction to the basic elements of conformal field theory as applied to systems with a current algebra, and we orient the reader by presenting a number of applications of non-Abelian bosonization to models with large symmetries. We then tie this technique into recent advances in the ability of cold atomic systems to realize complex symmetries. Secondly, we discuss truncated spectrum methods for the numerical study of systems in one and two dimensions. For one-dimensional systems we provide the reader with considerable insight into the methodology by reviewing canonical applications of the technique to the Ising model (and its variants) and the sine-Gordon model. Following this we review recent work on the development of renormalization groups, both numerical and analytical, that alleviate the effects of truncating the spectrum. Using these technologies, we consider a number of applications to one-dimensional systems: properties of carbon nanotubes, quenches in the Lieb–Liniger model, 1 + 1D quantum chromodynamics, as well as Landau–Ginzburg theories. In the final part we move our attention to consider truncated spectrum methods applied to two-dimensional systems. This involves combining truncated spectrum methods with matrix product state algorithms. We describe applications of this method to two-dimensional systems of free fermions and the quantum Ising model, including their non-equilibrium dynamics.
Susanti, Hesty; Suprijanto, Kurniadi, Deddy
2018-02-01
Needle visibility in ultrasound-guided technique has been a crucial factor for successful interventional procedure. It has been affected by several factors, i.e. puncture depth, insertion angle, needle size and material, and imaging technology. The influences of those factors made the needle not always well visible. 20 G needles of 15 cm length (Nano Line, facet) were inserted into water bath with variation of insertion angles and depths. Ultrasound measurements are performed with BK-Medical Flex Focus 800 using 12 MHz linear array and 5 MHz curved array in Ultrasound Guided Regional Anesthesia mode. We propose 3 criteria to evaluate needle visibility, i.e. maximum intensity, mean intensity, and the ratio between minimum and maximum intensity. Those criteria were then depicted into representative maps for practical purpose. The best criterion candidate for representing the needle visibility was criterion 1. Generally, the appearance pattern of the needle from this criterion was relatively consistent, i.e. for linear array, it was relatively poor visibility in the middle part of the shaft, while for curved array, it is relatively better visible toward the end of the shaft. With further investigations, for example with the use of tissue-mimicking phantom, the representative maps can be built for future practical purpose, i.e. as a tool for clinicians to ensure better needle placement in clinical application. It will help them to avoid the "dead" area where the needle is not well visible, so it can reduce the risks of vital structures traversing and the number of required insertion, resulting in less patient morbidity. Those simple criteria and representative maps can be utilized to evaluate general visibility patterns of the needle in vast range of needle types and sizes in different insertion media. This information is also important as an early investigation for future research of needle visibility improvement, i.e. the development of beamforming strategies and
Lim, Seng Han; Ng, Jian Yao; Kang, Lifeng
2017-01-10
The hand function of patients who suffer from trigger finger can be impaired by the use of traditional splints. There is also a risk of systemic side effects with oral non-steroidal anti-inflammatory drugs (NSAIDs) used for pain relief. Microneedle-assisted transdermal drug delivery offers an attractive alternative for local delivery of NSAIDs. However, traditional microneedle arrays fabricated on flat surfaces are unable to deliver drugs effectively across the undulating skin surface of affected finger(s). In this study, using 3D printing, a dual-function microneedle array has been fabricated on personalized curved surfaces (microneedle splint) for drug delivery and splinting of the affected finger. The novel microneedle splint was assessed for its physical characteristics and the microneedles were shown to withstand up to twice the average thumb force without fracturing. An average skin penetration efficiency of 64% on dermatomed human cadaver skin was achieved and the final microneedle splint showed biocompatibility with human dermal cell lines. A significantly higher amount of diclofenac permeated through the skin by 0.5 h with the use of the microneedle splint as compared to intact skin. The fabricated microneedle splint can thus be a potential new approach to treat trigger finger via personalized splinting without affecting normal hand function.
Omar, Jone; Olivares, Maitane; Amigo, José Manuel; Etxebarria, Nestor
2014-04-01
Comprehensive Two Dimensional Gas Chromatography - Mass Spectrometry (GC × GC/qMS) analysis of Cannabis sativa extracts shows a high complexity due to the large variety of terpenes and cannabinoids and to the fact that the complete resolution of the peaks is not straightforwardly achieved. In order to support the resolution of the co-eluted peaks in the sesquiterpene and the cannabinoid chromatographic region the combination of Multivariate Curve Resolution and Alternating Least Squares algorithms was satisfactorily applied. As a result, four co-eluting areas were totally resolved in the sesquiterpene region and one in the cannabinoid region in different samples of Cannabis sativa. The comparison of the mass spectral profiles obtained for each resolved peak with theoretical mass spectra allowed the identification of some of the co-eluted peaks. Finally, the classification of the studied samples was achieved based on the relative concentrations of the resolved peaks. Copyright © 2014 Elsevier B.V. All rights reserved.
Martínez, Sol Sáez; de la Rosa, Félix Martínez; Rojas, Sergio
2017-01-01
In Advanced Calculus, our students wonder if it is possible to graphically represent a tornado by means of a three-dimensional curve. In this paper, we show it is possible by providing the parametric equations of such tornado-shaped curves.
International Nuclear Information System (INIS)
Kirkpatrick, M.P.; Armfield, S.W.; Kent, J.H.
2003-01-01
A method is presented for representing curved boundaries for the solution of the Navier-Stokes equations on a non-uniform, staggered, three-dimensional Cartesian grid. The approach involves truncating the Cartesian cells at the boundary surface to create new cells which conform to the shape of the surface. We discuss in some detail the problems unique to the development of a cut cell method on a staggered grid. Methods for calculating the fluxes through the boundary cell faces, for representing pressure forces and for calculating the wall shear stress are derived and it is verified that the new scheme retains second-order accuracy in space. In addition, a novel 'cell-linking' method is developed which overcomes problems associated with the creation of small cells while avoiding the complexities involved with other cell-merging approaches. Techniques are presented for generating the geometric information required for the scheme based on the representation of the boundaries as quadric surfaces. The new method is tested for flow through a channel placed oblique to the grid and flow past a cylinder at Re=40 and is shown to give significant improvement over a staircase boundary formulation. Finally, it is used to calculate unsteady flow past a hemispheric protuberance on a plate at a Reynolds number of 800. Good agreement is obtained with experimental results for this flow
Signature Curves Statistics of DNA Supercoils
Shakiban, Cheri; Lloyd, Peter
2004-01-01
In this paper we describe the Euclidean signature curves for two dimensional closed curves in the plane and their generalization to closed space curves. The focus will be on discrete numerical methods for approximating such curves. Further we will apply these numerical methods to plot the signature curves related to three-dimensional simulated DNA supercoils. Our primary focus will be on statistical analysis of the data generated for the signature curves of the supercoils. We will try to esta...
Cox, Christopher
Low-order numerical methods are widespread in academic solvers and ubiquitous in industrial solvers due to their robustness and usability. High-order methods are less robust and more complicated to implement; however, they exhibit low numerical dissipation and have the potential to improve the accuracy of flow simulations at a lower computational cost when compared to low-order methods. This motivates our development of a high-order compact method using Huynh's flux reconstruction scheme for solving unsteady incompressible flow on unstructured grids. We use Chorin's classic artificial compressibility formulation with dual time stepping to solve unsteady flow problems. In 2D, an implicit non-linear lower-upper symmetric Gauss-Seidel scheme with backward Euler discretization is used to efficiently march the solution in pseudo time, while a second-order backward Euler discretization is used to march in physical time. We verify and validate implementation of the high-order method coupled with our implicit time stepping scheme using both steady and unsteady incompressible flow problems. The current implicit time stepping scheme is proven effective in satisfying the divergence-free constraint on the velocity field in the artificial compressibility formulation. The high-order solver is extended to 3D and parallelized using MPI. Due to its simplicity, time marching for 3D problems is done explicitly. The feasibility of using the current implicit time stepping scheme for large scale three-dimensional problems with high-order polynomial basis still remains to be seen. We directly use the aforementioned numerical solver to simulate pulsatile flow of a Newtonian blood-analog fluid through a rigid 180-degree curved artery model. One of the most physiologically relevant forces within the cardiovascular system is the wall shear stress. This force is important because atherosclerotic regions are strongly correlated with curvature and branching in the human vasculature, where the
The statistical mechanics of the classical two-dimensional Coulomb gas is exactly solved
International Nuclear Information System (INIS)
Samaj, L
2003-01-01
The model under consideration is a classical 2D Coulomb gas of pointlike positive and negative unit charges, interacting via a logarithmic potential. In the whole stability range of temperatures, the equilibrium statistical mechanics of this fluid model is exactly solvable via an equivalence with the integrable 2D sine-Gordon field theory. The exact solution includes the bulk thermodynamics, special cases of the surface thermodynamics and the large-distance asymptotic behaviour of the two-body correlation functions
Comment on connections between nonlinear evolution equations
International Nuclear Information System (INIS)
Fuchssteiner, B.; Hefter, E.F.
1981-01-01
An open problem raised in a recent paper by Chodos is treated. We explain the reason for the interrelation between the conservation laws of the Korteweg-de Vries (KdV) and sine-Gordon equations. We point out that it is due to a corresponding connection between the infinite-dimensional Abelian symmetry groups of these equations. While it has been known for a long time that a Baecklund transformation (in this case the Miura transformation) connects corresponding members of the KdV and the sine-Gordon families, it is quite obvious that no Baecklund transformation can exist between different members of these families. And since the KdV and sine-Gordon equations do not correspond to each other, one cannot expect a Baecklund transformation between them; nevertheless we can give explicit relations between their two-soliton solutions. No inverse scattering techniques are used in this paper
Hunter, Walter M.
This document contains detailed directions for constructing a device that mechanically produces the three-dimensional shape resulting from the rotation of any algebraic line or curve around either axis on the coordinate plant. The device was developed in response to student difficulty in visualizing, and thus grasping the mathematical principles…
Stability of time-dependent particle-like solutions of some wave equations
International Nuclear Information System (INIS)
Voronov, N.A.
1978-01-01
The proof of the nonstability of the one-dimensional periodical localized solutions of the equation with a spontaneously broken symmetry is given. The stability of the one-dimensional oscillating solutions of the sine-Gordon equation was also considered with regard to such perturbations. As it was expected these solutions proved to be stable
Period doubling and chaos in large area Josephson junctions induced by rf signals
DEFF Research Database (Denmark)
Olsen, O. H.; Samuelsen, Mogens Rugholm
1985-01-01
The influence of an applied rf signal on the emitted radiation from a large area Josephson junction is examined. A model of the system is presented in the framework of the one-dimensional sine-Gordon equation. The model linearizes for small and large values of the amplitude of the applied signal...
Directory of Open Access Journals (Sweden)
Ehab Malkawi
2014-01-01
Full Text Available The classical free Lagrangian admitting a constant of motion, in one- and two-dimensional space, is generalized using the Caputo derivative of fractional calculus. The corresponding metric is obtained and the fractional Christoffel symbols, Killing vectors, and Killing-Yano tensors are derived. Some exact solutions of these quantities are reported.
Flow over riblet curved surfaces
Energy Technology Data Exchange (ETDEWEB)
Loureiro, J B R; Freire, A P Silva, E-mail: atila@mecanica.ufrj.br [Mechanical Engineering Program, Federal University of Rio de Janeiro (COPPE/UFRJ), C.P. 68503, 21.941-972, Rio de Janeiro, RJ (Brazil)
2011-12-22
The present work studies the mechanics of turbulent drag reduction over curved surfaces by riblets. The effects of surface modification on flow separation over steep and smooth curved surfaces are investigated. Four types of two-dimensional surfaces are studied based on the morphometric parameters that describe the body of a blue whale. Local measurements of mean velocity and turbulence profiles are obtained through laser Doppler anemometry (LDA) and particle image velocimetry (PIV).
Energy Technology Data Exchange (ETDEWEB)
Schumacher, O.
2007-07-20
In this thesis magneto-resistance studies on evenly curved two-dimensional electron systems in cylindric geometry are presented and discussed. A principle first introduced by Prinz and co-workers in 1998 enables us to roll up thin semiconductor layer systems by taking advantage of internal elastic strain. The radius of such a semiconductor tube can be adjusted ranging from a few nanometers up to several micrometers. The tubes' shape and place on the substrate can be defined by lithographic methods which are presented in this work. Furthermore, we show rolled-up structures containing a two-dimensional electron system in the tube wall. With a special lithographic procedure we are able to structure, to contact and to roll up these 2D-electron-gases in Hall geometry. As a result, a cylindric two-dimensional electron system is produced, which experiences a modulation of the perpendicular magnetic field component. The radius of curvature of our structures is about 10 {mu}m, the carrier mobility is optimized to values up to 125,000 cm{sup 2}/Vs. In transport experiments on curved Hall bars containing two dimensional electron systems two Hall bar orientations, with respect to the curvature, may be distinguished. In this work both orientations, i.e. with a Hall bar along the tube curvature as well as a Hall bar along the tube axis, are presented and discussed. Measurements on Hall bars along the curvature show signatures in the longitudinal resistance, which can be understood with the help of the Landauer-Buttiker-formalism and the model of magnetic barriers. For Hall bars oriented along the tube axis the perpendicular magnetic field component averaged over the width of the bar defines the minimum position of the Shubnikov-de Haas-oscillations as well as the slope of the Hall resistance. Furthermore, measurements on so-called van the Pauw-lamellas are presented. In this geometry the magneto-resistance shows a slope which refers to highly mobile conditions at the zero
International Nuclear Information System (INIS)
Dobrowolski, Tomasz
2012-01-01
The constant curvature one and quasi-one dimensional Josephson junction is considered. On the base of Maxwell equations, the sine–Gordon equation that describes an influence of curvature on the kink motion was obtained. It is showed that the method of geometrical reduction of the sine–Gordon model from three to lower dimensional manifold leads to an identical form of the sine–Gordon equation. - Highlights: ► The research on dynamics of the phase in a curved Josephson junction is performed. ► The geometrical reduction is applied to the sine–Gordon model. ► The results of geometrical reduction and the fundamental research are compared.
Differential geometry and topology of curves
Animov, Yu
2001-01-01
Differential geometry is an actively developing area of modern mathematics. This volume presents a classical approach to the general topics of the geometry of curves, including the theory of curves in n-dimensional Euclidean space. The author investigates problems for special classes of curves and gives the working method used to obtain the conditions for closed polygonal curves. The proof of the Bakel-Werner theorem in conditions of boundedness for curves with periodic curvature and torsion is also presented. This volume also highlights the contributions made by great geometers. past and present, to differential geometry and the topology of curves.
Minimal families of curves on surfaces
Lubbes, Niels
2014-01-01
A minimal family of curves on an embedded surface is defined as a 1-dimensional family of rational curves of minimal degree, which cover the surface. We classify such minimal families using constructive methods. This allows us to compute the minimal
Lagrangian Curves on Spectral Curves of Monopoles
International Nuclear Information System (INIS)
Guilfoyle, Brendan; Khalid, Madeeha; Ramon Mari, Jose J.
2010-01-01
We study Lagrangian points on smooth holomorphic curves in TP 1 equipped with a natural neutral Kaehler structure, and prove that they must form real curves. By virtue of the identification of TP 1 with the space LE 3 of oriented affine lines in Euclidean 3-space, these Lagrangian curves give rise to ruled surfaces in E 3 , which we prove have zero Gauss curvature. Each ruled surface is shown to be the tangent lines to a curve in E 3 , called the edge of regression of the ruled surface. We give an alternative characterization of these curves as the points in E 3 where the number of oriented lines in the complex curve Σ that pass through the point is less than the degree of Σ. We then apply these results to the spectral curves of certain monopoles and construct the ruled surfaces and edges of regression generated by the Lagrangian curves.
On the structure on non-local conservation laws in the two-dimensional non-linear sigma-model
International Nuclear Information System (INIS)
Zamolodchikov, Al.B.
1978-01-01
The non-local conserved charges are supposed to satisfy a special multiplicative law in the space of asymptotic states of the non-linear sigma-model. This supposition leads to factorization equations for two-particle scattering matrix elements and determines to some extent the action of these charges in the asymptotic space. Their conservation turns out to be consistent with the factorized S-matrix of the non-linear sigma-model. It is shown also that the factorized sine-Gordon S-matrix is consistent with a similar family of conservation laws
Invariance for Single Curved Manifold
Castro, Pedro Machado Manhaes de
2012-01-01
Recently, it has been shown that, for Lambert illumination model, solely scenes composed by developable objects with a very particular albedo distribution produce an (2D) image with isolines that are (almost) invariant to light direction change. In this work, we provide and investigate a more general framework, and we show that, in general, the requirement for such in variances is quite strong, and is related to the differential geometry of the objects. More precisely, it is proved that single curved manifolds, i.e., manifolds such that at each point there is at most one principal curvature direction, produce invariant is surfaces for a certain relevant family of energy functions. In the three-dimensional case, the associated energy function corresponds to the classical Lambert illumination model with albedo. This result is also extended for finite-dimensional scenes composed by single curved objects. © 2012 IEEE.
Invariance for Single Curved Manifold
Castro, Pedro Machado Manhaes de
2012-08-01
Recently, it has been shown that, for Lambert illumination model, solely scenes composed by developable objects with a very particular albedo distribution produce an (2D) image with isolines that are (almost) invariant to light direction change. In this work, we provide and investigate a more general framework, and we show that, in general, the requirement for such in variances is quite strong, and is related to the differential geometry of the objects. More precisely, it is proved that single curved manifolds, i.e., manifolds such that at each point there is at most one principal curvature direction, produce invariant is surfaces for a certain relevant family of energy functions. In the three-dimensional case, the associated energy function corresponds to the classical Lambert illumination model with albedo. This result is also extended for finite-dimensional scenes composed by single curved objects. © 2012 IEEE.
Vertex algebras and algebraic curves
Frenkel, Edward
2004-01-01
Vertex algebras are algebraic objects that encapsulate the concept of operator product expansion from two-dimensional conformal field theory. Vertex algebras are fast becoming ubiquitous in many areas of modern mathematics, with applications to representation theory, algebraic geometry, the theory of finite groups, modular functions, topology, integrable systems, and combinatorics. This book is an introduction to the theory of vertex algebras with a particular emphasis on the relationship with the geometry of algebraic curves. The notion of a vertex algebra is introduced in a coordinate-independent way, so that vertex operators become well defined on arbitrary smooth algebraic curves, possibly equipped with additional data, such as a vector bundle. Vertex algebras then appear as the algebraic objects encoding the geometric structure of various moduli spaces associated with algebraic curves. Therefore they may be used to give a geometric interpretation of various questions of representation theory. The book co...
String Sigma Models on Curved Supermanifolds
Directory of Open Access Journals (Sweden)
Roberto Catenacci
2018-04-01
Full Text Available We use the techniques of integral forms to analyze the easiest example of two-dimensional sigma models on a supermanifold. We write the action as an integral of a top integral form over a D = 2 supermanifold, and we show how to interpolate between different superspace actions. Then, we consider curved supermanifolds, and we show that the definitions used for flat supermanifolds can also be used for curved supermanifolds. We prove it by first considering the case of a curved rigid supermanifold and then the case of a generic curved supermanifold described by a single superfield E.
DEFF Research Database (Denmark)
Bernstein, Daniel J.; Birkner, Peter; Lange, Tanja
2013-01-01
-arithmetic level are as follows: (1) use Edwards curves instead of Montgomery curves; (2) use extended Edwards coordinates; (3) use signed-sliding-window addition-subtraction chains; (4) batch primes to increase the window size; (5) choose curves with small parameters and base points; (6) choose curves with large...
Schlösser, Tom P C; van Stralen, M; Chu, Winnie C W; Lam, Tsz-Ping; Ng, Bobby K W; Vincken, Koen L; Cheng, Jack C Y; Castelein, RM
2016-01-01
INTRODUCTION: Although much attention has been given to the global three-dimensional aspect of adolescent idiopathic scoliosis (AIS), the accurate three-dimensional morphology of the primary and compensatory curves, as well as the intervening junctional segments, in the scoliotic spine has not been
Directory of Open Access Journals (Sweden)
Janusz Charatonik
1991-11-01
Full Text Available Results concerning contractibility of curves (equivalently: of dendroids are collected and discussed in the paper. Interrelations tetween various conditions which are either sufficient or necessary for a curve to be contractible are studied.
International Nuclear Information System (INIS)
Dietrich, R.
1984-01-01
The basic concepts of the finite element method are explained. The results are compared to existing calibration curves for such test piece geometries derived using experimental procedures. (orig./HP) [de
Domain shape dependence of semiclassical corrections to energy
International Nuclear Information System (INIS)
Kwiatkowski, Grzegorz
2017-01-01
Stationary solution of a one-dimensional sine-Gordon system is embedded in a multidimensional theory with an explicitly finite domain in the added spatial dimensions. Semiclassical corrections to energy are calculated for a static kink solution with emphasis on the impact of the scale of the domain as well as the choice of boundary conditions on the results for a rectangular cross-section. (paper)
Defect formation in long Josephson junctions
DEFF Research Database (Denmark)
Gordeeva, Anna; Pankratov, Andrey
2010-01-01
We study numerically a mechanism of vortex formation in a long Josephson junction within the framework of the one-dimensional sine-Gordon model. This mechanism is switched on below the critical temperature. It is shown that the number of fluxons versus velocity of cooling roughly scales according...... to the power law with the exponent of either 0.25 or 0.5 depending on the temperature variation in the critical current density....
Bianchi-Baecklund transformations, conservation laws, and linearization of various field theories
International Nuclear Information System (INIS)
Chau Wang, L.L.
1980-01-01
The discussion includes: the Sine-Gordon equation, parametric Bianchi-Baecklund transformations and the derivation of local conservation laws; chiral fields, parametric Bianchi-Baecklund transformations, local and non-local conservation laws, and linearization; super chiral fields, a parallel development similar to the chiral field; and self-dual Yang-Mills fields in 4-dimensional Euclidean space; loop-cpace chiral equations, parallel development but with subtlety
Complete integrability of the supersymmetric (cos phi)2 model
International Nuclear Information System (INIS)
Kulish, P.P.; Tsyplyaev, S.A.
1987-01-01
Complete integrability of the supersymmetric two-dimensional sine-Gordon field-theoretical model is proved in the framework of the Hamiltonian interpretation of the inverse problem method. The classical r-matrix of this model is computed and shown to be equivalent to the r-matrix of the Grassmann Thirring model. Creation-annihilation variables are constructed and the elementary excitation spectrum is determined
Complete integrability of the supersymmetric model (cos phi)/sub ell/
International Nuclear Information System (INIS)
Kulish, P.P.; Tsyplyaev, S.A.
1986-01-01
Complete integrability of the supersymmetric, two-dimensional sine-Gordon model of field theory within the framework of the Hamiltonian interpretation of the method of the inverse problem is proved. The classical r-matrix of the model is computed, and its equivalence to the r-matrix the Grassmann Thirring model is established. Variables of creation-annihilation type are constructed, and the spectrum of elementary excitations of the system is obtained
Quantum censorship in two dimensions
Energy Technology Data Exchange (ETDEWEB)
Pangon, V. [Frankfurt Institute for Advanced Studies, Universitaet Frankfurt, D-60438 Frankfurt am Main (Germany); Gesellschaft fuer Schwerionenforschung mbH, Planckstr. 1, D-64291 Darmstadt (Germany); Nagy, S. [Department of Theoretical Physics, University of Debrecen, Debrecen (Hungary); Polonyi, J., E-mail: polonyi@ires.in2p3.f [Strasbourg University, CNRS-IPHC, BP28 67037 Strasbourg Cedex 2 (France); Sailer, K. [Department of Theoretical Physics, University of Debrecen, Debrecen (Hungary)
2010-10-25
It is pointed out that increasingly attractive interactions, represented by partially concave local potential in the Lagrangian, may lead to the degeneracy of the blocked, renormalized action at the gliding cutoff scale by tree-level renormalization. A quantum counterpart of this mechanism is presented in the two-dimensional sine-Gordon model. The presence of Quantum Censorship is conjectured which makes the loop contributions pile up during the renormalization and thereby realize an approximate semiclassical effect.
Quantum censorship in two dimensions
International Nuclear Information System (INIS)
Pangon, V.; Nagy, S.; Polonyi, J.; Sailer, K.
2010-01-01
It is pointed out that increasingly attractive interactions, represented by partially concave local potential in the Lagrangian, may lead to the degeneracy of the blocked, renormalized action at the gliding cutoff scale by tree-level renormalization. A quantum counterpart of this mechanism is presented in the two-dimensional sine-Gordon model. The presence of Quantum Censorship is conjectured which makes the loop contributions pile up during the renormalization and thereby realize an approximate semiclassical effect.
Large-degree asymptotics of rational Painlevé-II functions: noncritical behaviour
International Nuclear Information System (INIS)
Buckingham, Robert J; Miller, Peter D
2014-01-01
Rational solutions of the inhomogeneous Painlevé-II equation and of a related coupled Painlevé-II system have recently arisen in studies of fluid vortices and of the sine-Gordon equation. For the sine-Gordon application in particular it is of interest to understand the large-degree asymptotic behaviour of the rational Painlevé-II functions. We explicitly compute the leading-order large-degree asymptotics of these two families of rational functions valid in the whole complex plane with the exception of a neighbourhood of a certain piecewise-smooth closed curve. We obtain rigorous error bounds by using the Deift–Zhou nonlinear steepest-descent method for Riemann–Hilbert problems. (paper)
International Nuclear Information System (INIS)
Carvalho-Santos, Vagson L.; Dandoloff, Rossen
2013-01-01
We study the Heisenberg model in an external magnetic field on curved surfaces with rotational symmetry. The Euler-Lagrange static equations, derived from the Hamiltonian, lead to the inhomogeneous double sine-Gordon equation. Nonetheless, if the magnetic field is coupled to the metric elements of the surface, and consequently to its curvature, the homogeneous double sine-Gordon equation emerges and a 2π-soliton solution is obtained. In order to satisfy the self-dual equations, surface deformations are predicted to appear at the sector where the spin direction is opposite to the magnetic field. On the basis of the model, we find the characteristic length of the 2π-soliton for three specific rotationally symmetric surfaces: the cylinder, the catenoid, and the hyperboloid. On finite surfaces, such as the sphere, torus, and barrels, fractional 2π-solitons are predicted to appear. (author)
Introduction to integrable many-body systems III
International Nuclear Information System (INIS)
Bajnok, Z.; Samaj, L.
2011-01-01
This is the third part of a three-volume introductory course about integrable systems of interacting bodies. The emphasis is put onto the method of Thermodynamic Bethe Ansatz. Two kinds of integrable models are studied. Systems of itinerant electrons, forming a part of Condensed Matter Physics, involve the Hubbard lattice model of electrons with short-ranged one-site interactions (Sect. 20) and the s-d exchange Kondo model (Sect. 21), describing the scattering of conduction electrons on a spin-s impurity. Methods and basic concepts used in Quantum Field Theory are explained on the integrable (1 + 1)-dimensional sine-Gordon model. We start with the classical description of the model in Sect. 22, analyze its finite energy field configurations (soliton, anti-soliton and breathers) and show its classical integrability. The model is quantized by using two schemes: the conformal (Sect. 23) and Lagrangian (Sect. 24) quantizations. The scattering matrix of the sine-Gordon theory is derived at the full quantum level in the bootstrap scheme and is compared to its classical limit in Sect. 25. The parameters of the scattering matrix are related to those of the Lagrangian by calculating the ground-state energy in an applied magnetic field in two ways: Conformal perturbation theory and Thermodynamic Bethe Ansatz (Sect. 26). The relation of the sine-Gordon theory to the XXZ Heisenberg model, which provides a complete solution of the sine-Gordon model in a finite volume, is pointed out in Sect. 27. The obtained results are applied in Sect. 28. to the derivation of the exact thermodynamics for the (symmetric) two-component Coulomb gas; this is the first classical two-dimensional fluid with exactly solvable thermodynamics (Authors)
Directory of Open Access Journals (Sweden)
René Pellissier
2012-01-01
Full Text Available This paper explores the notion ofjump ing the curve,following from Handy 's S-curve onto a new curve with new rules policies and procedures. . It claims that the curve does not generally lie in wait but has to be invented by leadership. The focus of this paper is the identification (mathematically and inferentially ofthat point in time, known as the cusp in catastrophe theory, when it is time to change - pro-actively, pre-actively or reactively. These three scenarios are addressed separately and discussed in terms ofthe relevance ofeach.
Nonlinear Klein-Gordon soliton mechanics
International Nuclear Information System (INIS)
Reinisch, G.
1992-01-01
Nonlinear Klein-Gordon solitary waves - or solitons in a loose sense - in n+1 dimensions, driven by very general external fields which must only satisfy continuity - together with regularity conditions at the boundaries of the system, obey a quite simple equation of motion. This equation is the exact generalization to this dynamical system of infinite number of degrees of freedom - which may be conservative or not - of the second Newton's law setting the basis of material point mechanics. In the restricted case of conservative nonlinear Klein-Gordon systems, where the external driving force is derivable from a potential energy, we recover the generalized Ehrenfest theorem which was itself the extension to such systems of the well-known Ehrenfest theorem in quantum mechanics. This review paper first displays a few (of one-dimensional sine-Gordon type) typical examples of the basic difficulties related to the trial construction of solitary-waves is proved and the derivation of the previous sine-Gordon examples from this theorem is displayed. Two-dimensional nonlinear solitary-wave patterns are considered, as well as a special emphasis is put on the applications to space-time complexity of 1-dim. sine-Gordon systems
Projection-based curve clustering
International Nuclear Information System (INIS)
Auder, Benjamin; Fischer, Aurelie
2012-01-01
This paper focuses on unsupervised curve classification in the context of nuclear industry. At the Commissariat a l'Energie Atomique (CEA), Cadarache (France), the thermal-hydraulic computer code CATHARE is used to study the reliability of reactor vessels. The code inputs are physical parameters and the outputs are time evolution curves of a few other physical quantities. As the CATHARE code is quite complex and CPU time-consuming, it has to be approximated by a regression model. This regression process involves a clustering step. In the present paper, the CATHARE output curves are clustered using a k-means scheme, with a projection onto a lower dimensional space. We study the properties of the empirically optimal cluster centres found by the clustering method based on projections, compared with the 'true' ones. The choice of the projection basis is discussed, and an algorithm is implemented to select the best projection basis among a library of orthonormal bases. The approach is illustrated on a simulated example and then applied to the industrial problem. (authors)
Simulating Supernova Light Curves
International Nuclear Information System (INIS)
Even, Wesley Paul; Dolence, Joshua C.
2016-01-01
This report discusses supernova light simulations. A brief review of supernovae, basics of supernova light curves, simulation tools used at LANL, and supernova results are included. Further, it happens that many of the same methods used to generate simulated supernova light curves can also be used to model the emission from fireballs generated by explosions in the earth's atmosphere.
Simulating Supernova Light Curves
Energy Technology Data Exchange (ETDEWEB)
Even, Wesley Paul [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dolence, Joshua C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2016-05-05
This report discusses supernova light simulations. A brief review of supernovae, basics of supernova light curves, simulation tools used at LANL, and supernova results are included. Further, it happens that many of the same methods used to generate simulated supernova light curves can also be used to model the emission from fireballs generated by explosions in the earth’s atmosphere.
Image scaling curve generation
2012-01-01
The present invention relates to a method of generating an image scaling curve, where local saliency is detected in a received image. The detected local saliency is then accumulated in the first direction. A final scaling curve is derived from the detected local saliency and the image is then
Image scaling curve generation.
2011-01-01
The present invention relates to a method of generating an image scaling curve, where local saliency is detected in a received image. The detected local saliency is then accumulated in the first direction. A final scaling curve is derived from the detected local saliency and the image is then
Tempo curves considered harmful
Desain, P.; Honing, H.
1993-01-01
In the literature of musicology, computer music research and the psychology of music, timing or tempo measurements are mostly presented in the form of continuous curves. The notion of these tempo curves is dangerous, despite its widespread use, because it lulls its users into the false impression
Chou, Kai-Seng
2001-01-01
Although research in curve shortening flow has been very active for nearly 20 years, the results of those efforts have remained scattered throughout the literature. For the first time, The Curve Shortening Problem collects and illuminates those results in a comprehensive, rigorous, and self-contained account of the fundamental results.The authors present a complete treatment of the Gage-Hamilton theorem, a clear, detailed exposition of Grayson''s convexity theorem, a systematic discussion of invariant solutions, applications to the existence of simple closed geodesics on a surface, and a new, almost convexity theorem for the generalized curve shortening problem.Many questions regarding curve shortening remain outstanding. With its careful exposition and complete guide to the literature, The Curve Shortening Problem provides not only an outstanding starting point for graduate students and new investigations, but a superb reference that presents intriguing new results for those already active in the field.
Directory of Open Access Journals (Sweden)
Paulo Prochno
2004-07-01
Full Text Available Learning curves have been studied for a long time. These studies provided strong support to the hypothesis that, as organizations produce more of a product, unit costs of production decrease at a decreasing rate (see Argote, 1999 for a comprehensive review of learning curve studies. But the organizational mechanisms that lead to these results are still underexplored. We know some drivers of learning curves (ADLER; CLARK, 1991; LAPRE et al., 2000, but we still lack a more detailed view of the organizational processes behind those curves. Through an ethnographic study, I bring a comprehensive account of the first year of operations of a new automotive plant, describing what was taking place on in the assembly area during the most relevant shifts of the learning curve. The emphasis is then on how learning occurs in that setting. My analysis suggests that the overall learning curve is in fact the result of an integration process that puts together several individual ongoing learning curves in different areas throughout the organization. In the end, I propose a model to understand the evolution of these learning processes and their supporting organizational mechanisms.
Buonanno, Paolo; Fergusson, Leopoldo; Vargas, Juan Fernando
2014-01-01
We document the existence of a Crime Kuznets Curve in US states since the 1970s. As income levels have risen, crime has followed an inverted U-shaped pattern, first increasing and then dropping. The Crime Kuznets Curve is not explained by income inequality. In fact, we show that during the sample period inequality has risen monotonically with income, ruling out the traditional Kuznets Curve. Our finding is robust to adding a large set of controls that are used in the literature to explain the...
Directory of Open Access Journals (Sweden)
Kožul Nataša
2014-01-01
Full Text Available In the broadest sense, yield curve indicates the market's view of the evolution of interest rates over time. However, given that cost of borrowing it closely linked to creditworthiness (ability to repay, different yield curves will apply to different currencies, market sectors, or even individual issuers. As government borrowing is indicative of interest rate levels available to other market players in a particular country, and considering that bond issuance still remains the dominant form of sovereign debt, this paper describes yield curve construction using bonds. The relationship between zero-coupon yield, par yield and yield to maturity is given and their usage in determining curve discount factors is described. Their usage in deriving forward rates and pricing related derivative instruments is also discussed.
U.S. Environmental Protection Agency — an UV calibration curve for SRHA quantitation. This dataset is associated with the following publication: Chang, X., and D. Bouchard. Surfactant-Wrapped Multiwalled...
International Nuclear Information System (INIS)
Gruhn, C.R.
1981-05-01
An alternative utilization is presented for the gaseous ionization chamber in the detection of energetic heavy ions, which is called Bragg Curve Spectroscopy (BCS). Conceptually, BCS involves using the maximum data available from the Bragg curve of the stopping heavy ion (HI) for purposes of identifying the particle and measuring its energy. A detector has been designed that measures the Bragg curve with high precision. From the Bragg curve the range from the length of the track, the total energy from the integral of the specific ionization over the track, the dE/dx from the specific ionization at the beginning of the track, and the Bragg peak from the maximum of the specific ionization of the HI are determined. This last signal measures the atomic number, Z, of the HI unambiguously
Directory of Open Access Journals (Sweden)
Sutawanir Darwis
2012-05-01
Full Text Available Empirical decline curve analysis of oil production data gives reasonable answer in hyperbolic type curves situations; however the methodology has limitations in fitting real historical production data in present of unusual observations due to the effect of the treatment to the well in order to increase production capacity. The development ofrobust least squares offers new possibilities in better fitting production data using declinecurve analysis by down weighting the unusual observations. This paper proposes a robustleast squares fitting lmRobMM approach to estimate the decline rate of daily production data and compares the results with reservoir simulation results. For case study, we usethe oil production data at TBA Field West Java. The results demonstrated that theapproach is suitable for decline curve fitting and offers a new insight in decline curve analysis in the present of unusual observations.
INEXTENSIBLE FLOWS OF CURVES IN THE EQUIFORM GEOMETRY OF THE PSEUDO-GALILEAN SPACE G13
Directory of Open Access Journals (Sweden)
HANDAN OZTEKIN
2016-12-01
Full Text Available In this paper, we study inextensible ows of curves in 3-dimensional pseudo- Galilean space. We give necessary and sucient conditions for inextensible ows of curves according to equiform geometry in pseudo-Galilean space.
DEFF Research Database (Denmark)
Georgieva Yankova, Ginka; Federici, Paolo
This report describes power curve measurements carried out on a given turbine in a chosen period. The measurements are carried out in accordance to IEC 61400-12-1 Ed. 1 and FGW Teil 2.......This report describes power curve measurements carried out on a given turbine in a chosen period. The measurements are carried out in accordance to IEC 61400-12-1 Ed. 1 and FGW Teil 2....
Alexeev, Valery; Clemens, C Herbert; Beauville, Arnaud
2008-01-01
This book is devoted to recent progress in the study of curves and abelian varieties. It discusses both classical aspects of this deep and beautiful subject as well as two important new developments, tropical geometry and the theory of log schemes. In addition to original research articles, this book contains three surveys devoted to singularities of theta divisors, of compactified Jacobians of singular curves, and of "strange duality" among moduli spaces of vector bundles on algebraic varieties.
F(α) curves: Experimental results
International Nuclear Information System (INIS)
Glazier, J.A.; Gunaratne, G.; Libchaber, A.
1988-01-01
We study the transition to chaos at the golden and silver means for forced Rayleigh-Benard (RB) convection in mercury. We present f(α) curves below, at, and above the transition, and provide comparisons to the curves calculated for the one-dimensional circle map. We find good agreement at both the golden and silver means. This confirms our earlier observation that for low amplitude forcing, forced RB convection is well described by the one-dimensional circle map and indicates that the f(α) curve is a good measure of the approach to criticality. For selected subcritical experimental data sets we calculate the degree of subcriticality. We also present both experimental and calculated results for f(α) in the presence of a third frequency. Again we obtain agreement: The presence of random noise or a third frequency narrows the right-hand (negative q) side of the f(α) curve. Subcriticality results in symmetrically narrowed curves. We can also distinguish these cases by examining the power spectra and Poincare sections of the time series
From Curve Fitting to Machine Learning
Zielesny, Achim
2011-01-01
The analysis of experimental data is at heart of science from its beginnings. But it was the advent of digital computers that allowed the execution of highly non-linear and increasingly complex data analysis procedures - methods that were completely unfeasible before. Non-linear curve fitting, clustering and machine learning belong to these modern techniques which are a further step towards computational intelligence. The goal of this book is to provide an interactive and illustrative guide to these topics. It concentrates on the road from two dimensional curve fitting to multidimensional clus
Approximation by planar elastic curves
DEFF Research Database (Denmark)
Brander, David; Gravesen, Jens; Nørbjerg, Toke Bjerge
2016-01-01
We give an algorithm for approximating a given plane curve segment by a planar elastic curve. The method depends on an analytic representation of the space of elastic curve segments, together with a geometric method for obtaining a good initial guess for the approximating curve. A gradient......-driven optimization is then used to find the approximating elastic curve....
Path integrals on curved manifolds
International Nuclear Information System (INIS)
Grosche, C.; Steiner, F.
1987-01-01
A general framework for treating path integrals on curved manifolds is presented. We also show how to perform general coordinate and space-time transformations in path integrals. The main result is that one has to subtract a quantum correction ΔV ∝ ℎ 2 from the classical Lagrangian L, i.e. the correct effective Lagrangian to be used in the path integral is L eff = L-ΔV. A general prescription for calculating the quantum correction ΔV is given. It is based on a canonical approach using Weyl-ordering and the Hamiltonian path integral defined by the midpoint prescription. The general framework is illustrated by several examples: The d-dimensional rotator, i.e. the motion on the sphere S d-1 , the path integral in d-dimensional polar coordinates, the exact treatment of the hydrogen atom in R 2 and R 3 by performing a Kustaanheimo-Stiefel transformation, the Langer transformation and the path integral for the Morse potential. (orig.)
DEFF Research Database (Denmark)
Gómez Arranz, Paula; Vesth, Allan
This report describes the power curve measurements carried out on a given wind turbine in a chosen period. The measurements were carried out following the measurement procedure in the draft of IEC 61400-12-1 Ed.2 [1], with some deviations mostly regarding uncertainty calculation. Here, the refere......This report describes the power curve measurements carried out on a given wind turbine in a chosen period. The measurements were carried out following the measurement procedure in the draft of IEC 61400-12-1 Ed.2 [1], with some deviations mostly regarding uncertainty calculation. Here......, the reference wind speed used in the power curve is the equivalent wind speed obtained from lidar measurements at several heights between lower and upper blade tip, in combination with a hub height meteorological mast. The measurements have been performed using DTU’s measurement equipment, the analysis...
Curved electromagnetic missiles
International Nuclear Information System (INIS)
Myers, J.M.; Shen, H.M.; Wu, T.T.
1989-01-01
Transient electromagnetic fields can exhibit interesting behavior in the limit of great distances from their sources. In situations of finite total radiated energy, the energy reaching a distant receiver can decrease with distance much more slowly than the usual r - 2 . Cases of such slow decrease have been referred to as electromagnetic missiles. All of the wide variety of known missiles propagate in essentially straight lines. A sketch is presented here of a missile that can follow a path that is strongly curved. An example of a curved electromagnetic missile is explicitly constructed and some of its properties are discussed. References to details available elsewhere are given
Algebraic curves and cryptography
Murty, V Kumar
2010-01-01
It is by now a well-known paradigm that public-key cryptosystems can be built using finite Abelian groups and that algebraic geometry provides a supply of such groups through Abelian varieties over finite fields. Of special interest are the Abelian varieties that are Jacobians of algebraic curves. All of the articles in this volume are centered on the theme of point counting and explicit arithmetic on the Jacobians of curves over finite fields. The topics covered include Schoof's \\ell-adic point counting algorithm, the p-adic algorithms of Kedlaya and Denef-Vercauteren, explicit arithmetic on
IGMtransmission: Transmission curve computation
Harrison, Christopher M.; Meiksin, Avery; Stock, David
2015-04-01
IGMtransmission is a Java graphical user interface that implements Monte Carlo simulations to compute the corrections to colors of high-redshift galaxies due to intergalactic attenuation based on current models of the Intergalactic Medium. The effects of absorption due to neutral hydrogen are considered, with particular attention to the stochastic effects of Lyman Limit Systems. Attenuation curves are produced, as well as colors for a wide range of filter responses and model galaxy spectra. Photometric filters are included for the Hubble Space Telescope, the Keck telescope, the Mt. Palomar 200-inch, the SUBARU telescope and UKIRT; alternative filter response curves and spectra may be readily uploaded.
Differential geometry of curves and surfaces
Banchoff, Thomas F
2010-01-01
Students and professors of an undergraduate course in differential geometry will appreciate the clear exposition and comprehensive exercises in this book that focuses on the geometric properties of curves and surfaces, one- and two-dimensional objects in Euclidean space. The problems generally relate to questions of local properties (the properties observed at a point on the curve or surface) or global properties (the properties of the object as a whole). Some of the more interesting theorems explore relationships between local and global properties. A special feature is the availability of accompanying online interactive java applets coordinated with each section. The applets allow students to investigate and manipulate curves and surfaces to develop intuition and to help analyze geometric phenomena.
Deep-learnt classification of light curves
DEFF Research Database (Denmark)
Mahabal, Ashish; Gieseke, Fabian; Pai, Akshay Sadananda Uppinakudru
2017-01-01
is to derive statistical features from the time series and to use machine learning methods, generally supervised, to separate objects into a few of the standard classes. In this work, we transform the time series to two-dimensional light curve representations in order to classify them using modern deep......Astronomy light curves are sparse, gappy, and heteroscedastic. As a result standard time series methods regularly used for financial and similar datasets are of little help and astronomers are usually left to their own instruments and techniques to classify light curves. A common approach...... learning techniques. In particular, we show that convolutional neural networks based classifiers work well for broad characterization and classification. We use labeled datasets of periodic variables from CRTS survey and show how this opens doors for a quick classification of diverse classes with several...
Minimal families of curves on surfaces
Lubbes, Niels
2014-11-01
A minimal family of curves on an embedded surface is defined as a 1-dimensional family of rational curves of minimal degree, which cover the surface. We classify such minimal families using constructive methods. This allows us to compute the minimal families of a given surface.The classification of minimal families of curves can be reduced to the classification of minimal families which cover weak Del Pezzo surfaces. We classify the minimal families of weak Del Pezzo surfaces and present a table with the number of minimal families of each weak Del Pezzo surface up to Weyl equivalence.As an application of this classification we generalize some results of Schicho. We classify algebraic surfaces that carry a family of conics. We determine the minimal lexicographic degree for the parametrization of a surface that carries at least 2 minimal families. © 2014 Elsevier B.V.
Learning from uncertain curves
DEFF Research Database (Denmark)
Mallasto, Anton; Feragen, Aasa
2017-01-01
We introduce a novel framework for statistical analysis of populations of nondegenerate Gaussian processes (GPs), which are natural representations of uncertain curves. This allows inherent variation or uncertainty in function-valued data to be properly incorporated in the population analysis. Us...
DEFF Research Database (Denmark)
Federici, Paolo; Kock, Carsten Weber
This report describes the power curve measurements performed with a nacelle LIDAR on a given wind turbine in a wind farm and during a chosen measurement period. The measurements and analysis are carried out in accordance to the guidelines in the procedure “DTU Wind Energy-E-0019” [1]. The reporting...
DEFF Research Database (Denmark)
Vesth, Allan; Kock, Carsten Weber
The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...... analyze of power performance of the turbine....
DEFF Research Database (Denmark)
Federici, Paolo; Vesth, Allan
The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...... analyze of power performance of the turbine....
DEFF Research Database (Denmark)
Villanueva, Héctor; Gómez Arranz, Paula
The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...... analyze of power performance of the turbine...
Groot, L.F.M.|info:eu-repo/dai/nl/073642398
2008-01-01
The purpose of this paper is twofold. First, it exhibits that standard tools in the measurement of income inequality, such as the Lorenz curve and the Gini-index, can successfully be applied to the issues of inequality measurement of carbon emissions and the equity of abatement policies across
DEFF Research Database (Denmark)
Gómez Arranz, Paula; Wagner, Rozenn
This report describes the power curve measurements performed with a nacelle LIDAR on a given wind turbine in a wind farm and during a chosen measurement period. The measurements and analysis are carried out in accordance to the guidelines in the procedure “DTU Wind Energy-E-0019” [1]. The reporting...
DEFF Research Database (Denmark)
Vesth, Allan; Kock, Carsten Weber
The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...
Textbook Factor Demand Curves.
Davis, Joe C.
1994-01-01
Maintains that teachers and textbook graphics follow the same basic pattern in illustrating changes in demand curves when product prices increase. Asserts that the use of computer graphics will enable teachers to be more precise in their graphic presentation of price elasticity. (CFR)
Bernstein, D.J.; Birkner, P.; Lange, T.; Peters, C.P.
2013-01-01
This paper introduces EECM-MPFQ, a fast implementation of the elliptic-curve method of factoring integers. EECM-MPFQ uses fewer modular multiplications than the well-known GMP-ECM software, takes less time than GMP-ECM, and finds more primes than GMP-ECM. The main improvements above the
DEFF Research Database (Denmark)
Federici, Paolo; Kock, Carsten Weber
The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...... analyze of power performance of the turbine...
Light extraction block with curved surface
Levermore, Peter; Krall, Emory; Silvernail, Jeffrey; Rajan, Kamala; Brown, Julia J.
2016-03-22
Light extraction blocks, and OLED lighting panels using light extraction blocks, are described, in which the light extraction blocks include various curved shapes that provide improved light extraction properties compared to parallel emissive surface, and a thinner form factor and better light extraction than a hemisphere. Lighting systems described herein may include a light source with an OLED panel. A light extraction block with a three-dimensional light emitting surface may be optically coupled to the light source. The three-dimensional light emitting surface of the block may includes a substantially curved surface, with further characteristics related to the curvature of the surface at given points. A first radius of curvature corresponding to a maximum principal curvature k.sub.1 at a point p on the substantially curved surface may be greater than a maximum height of the light extraction block. A maximum height of the light extraction block may be less than 50% of a maximum width of the light extraction block. Surfaces with cross sections made up of line segments and inflection points may also be fit to approximated curves for calculating the radius of curvature.
Walker, Judy L
2000-01-01
When information is transmitted, errors are likely to occur. Coding theory examines efficient ways of packaging data so that these errors can be detected, or even corrected. The traditional tools of coding theory have come from combinatorics and group theory. Lately, however, coding theorists have added techniques from algebraic geometry to their toolboxes. In particular, by re-interpreting the Reed-Solomon codes, one can see how to define new codes based on divisors on algebraic curves. For instance, using modular curves over finite fields, Tsfasman, Vladut, and Zink showed that one can define a sequence of codes with asymptotically better parameters than any previously known codes. This monograph is based on a series of lectures the author gave as part of the IAS/PCMI program on arithmetic algebraic geometry. Here, the reader is introduced to the exciting field of algebraic geometric coding theory. Presenting the material in the same conversational tone of the lectures, the author covers linear codes, inclu...
Energy Technology Data Exchange (ETDEWEB)
Groot, L. [Utrecht University, Utrecht School of Economics, Janskerkhof 12, 3512 BL Utrecht (Netherlands)
2008-11-15
The purpose of this paper is twofold. First, it exhibits that standard tools in the measurement of income inequality, such as the Lorenz curve and the Gini-index, can successfully be applied to the issues of inequality measurement of carbon emissions and the equity of abatement policies across countries. These tools allow policy-makers and the general public to grasp at a single glance the impact of conventional distribution rules such as equal caps or grandfathering, or more sophisticated ones, on the distribution of greenhouse gas emissions. Second, using the Samuelson rule for the optimal provision of a public good, the Pareto-optimal distribution of carbon emissions is compared with the distribution that follows if countries follow Nash-Cournot abatement strategies. It is shown that the Pareto-optimal distribution under the Samuelson rule can be approximated by the equal cap division, represented by the diagonal in the Lorenz curve diagram.
Pelce, Pierre
1989-01-01
In recent years, much progress has been made in the understanding of interface dynamics of various systems: hydrodynamics, crystal growth, chemical reactions, and combustion. Dynamics of Curved Fronts is an important contribution to this field and will be an indispensable reference work for researchers and graduate students in physics, applied mathematics, and chemical engineering. The book consist of a 100 page introduction by the editor and 33 seminal articles from various disciplines.
David G. Blanchflower; Andrew J. Oswald
1992-01-01
The paper provides evidence for the existence of a negatively sloped locus linking the level of pay to the rate of regional (or industry) unemployment. This "wage curve" is estimated using microeconomic data for Britain, the US, Canada, Korea, Austria, Italy, Holland, Switzerland, Norway, and Germany, The average unemployment elasticity of pay is approximately -0.1. The paper sets out a multi-region efficiency wage model and argues that its predictions are consistent with the data.
Anatomical curve identification
Bowman, Adrian W.; Katina, Stanislav; Smith, Joanna; Brown, Denise
2015-01-01
Methods for capturing images in three dimensions are now widely available, with stereo-photogrammetry and laser scanning being two common approaches. In anatomical studies, a number of landmarks are usually identified manually from each of these images and these form the basis of subsequent statistical analysis. However, landmarks express only a very small proportion of the information available from the images. Anatomically defined curves have the advantage of providing a much richer expression of shape. This is explored in the context of identifying the boundary of breasts from an image of the female torso and the boundary of the lips from a facial image. The curves of interest are characterised by ridges or valleys. Key issues in estimation are the ability to navigate across the anatomical surface in three-dimensions, the ability to recognise the relevant boundary and the need to assess the evidence for the presence of the surface feature of interest. The first issue is addressed by the use of principal curves, as an extension of principal components, the second by suitable assessment of curvature and the third by change-point detection. P-spline smoothing is used as an integral part of the methods but adaptations are made to the specific anatomical features of interest. After estimation of the boundary curves, the intermediate surfaces of the anatomical feature of interest can be characterised by surface interpolation. This allows shape variation to be explored using standard methods such as principal components. These tools are applied to a collection of images of women where one breast has been reconstructed after mastectomy and where interest lies in shape differences between the reconstructed and unreconstructed breasts. They are also applied to a collection of lip images where possible differences in shape between males and females are of interest. PMID:26041943
Estimating Corporate Yield Curves
Antionio Diaz; Frank Skinner
2001-01-01
This paper represents the first study of retail deposit spreads of UK financial institutions using stochastic interest rate modelling and the market comparable approach. By replicating quoted fixed deposit rates using the Black Derman and Toy (1990) stochastic interest rate model, we find that the spread between fixed and variable rates of interest can be modeled (and priced) using an interest rate swap analogy. We also find that we can estimate an individual bank deposit yield curve as a spr...
Vo, Martin
2017-08-01
Light Curves Classifier uses data mining and machine learning to obtain and classify desired objects. This task can be accomplished by attributes of light curves or any time series, including shapes, histograms, or variograms, or by other available information about the inspected objects, such as color indices, temperatures, and abundances. After specifying features which describe the objects to be searched, the software trains on a given training sample, and can then be used for unsupervised clustering for visualizing the natural separation of the sample. The package can be also used for automatic tuning parameters of used methods (for example, number of hidden neurons or binning ratio). Trained classifiers can be used for filtering outputs from astronomical databases or data stored locally. The Light Curve Classifier can also be used for simple downloading of light curves and all available information of queried stars. It natively can connect to OgleII, OgleIII, ASAS, CoRoT, Kepler, Catalina and MACHO, and new connectors or descriptors can be implemented. In addition to direct usage of the package and command line UI, the program can be used through a web interface. Users can create jobs for ”training” methods on given objects, querying databases and filtering outputs by trained filters. Preimplemented descriptors, classifier and connectors can be picked by simple clicks and their parameters can be tuned by giving ranges of these values. All combinations are then calculated and the best one is used for creating the filter. Natural separation of the data can be visualized by unsupervised clustering.
Uniformization of elliptic curves
Ülkem, Özge; Ulkem, Ozge
2015-01-01
Every elliptic curve E defined over C is analytically isomorphic to C*=qZ for some q ∊ C*. Similarly, Tate has shown that if E is defined over a p-adic field K, then E is analytically isomorphic to K*=qZ for some q ∊ K . Further the isomorphism E(K) ≅ K*/qZ respects the action of the Galois group GK/K, where K is the algebraic closure of K. I will explain the construction of this isomorphism.
Roc curves for continuous data
Krzanowski, Wojtek J
2009-01-01
Since ROC curves have become ubiquitous in many application areas, the various advances have been scattered across disparate articles and texts. ROC Curves for Continuous Data is the first book solely devoted to the subject, bringing together all the relevant material to provide a clear understanding of how to analyze ROC curves.The fundamental theory of ROC curvesThe book first discusses the relationship between the ROC curve and numerous performance measures and then extends the theory into practice by describing how ROC curves are estimated. Further building on the theory, the authors prese
Closed Timelike Curves in Type II Non-Vacuum Spacetime
International Nuclear Information System (INIS)
Ahmed, Faizuddin
2017-01-01
Here we present a cyclicly symmetric non-vacuum spacetime, admitting closed timelike curves (CTCs) which appear after a certain instant of time, i.e., a time-machine spacetime. The spacetime is asymptotically flat, free-from curvature singularities and a four-dimensional extension of the Misner space in curved spacetime. The spacetime is of type II in the Petrov classification scheme and the matter field pure radiation satisfy the energy condition. (paper)
Covariant quantizations in plane and curved spaces
International Nuclear Information System (INIS)
Assirati, J.L.M.; Gitman, D.M.
2017-01-01
We present covariant quantization rules for nonsingular finite-dimensional classical theories with flat and curved configuration spaces. In the beginning, we construct a family of covariant quantizations in flat spaces and Cartesian coordinates. This family is parametrized by a function ω(θ), θ element of (1,0), which describes an ambiguity of the quantization. We generalize this construction presenting covariant quantizations of theories with flat configuration spaces but already with arbitrary curvilinear coordinates. Then we construct a so-called minimal family of covariant quantizations for theories with curved configuration spaces. This family of quantizations is parametrized by the same function ω(θ). Finally, we describe a more wide family of covariant quantizations in curved spaces. This family is already parametrized by two functions, the previous one ω(θ) and by an additional function Θ(x,ξ). The above mentioned minimal family is a part at Θ = 1 of the wide family of quantizations. We study constructed quantizations in detail, proving their consistency and covariance. As a physical application, we consider a quantization of a non-relativistic particle moving in a curved space, discussing the problem of a quantum potential. Applying the covariant quantizations in flat spaces to an old problem of constructing quantum Hamiltonian in polar coordinates, we directly obtain a correct result. (orig.)
Covariant quantizations in plane and curved spaces
Energy Technology Data Exchange (ETDEWEB)
Assirati, J.L.M. [University of Sao Paulo, Institute of Physics, Sao Paulo (Brazil); Gitman, D.M. [Tomsk State University, Department of Physics, Tomsk (Russian Federation); P.N. Lebedev Physical Institute, Moscow (Russian Federation); University of Sao Paulo, Institute of Physics, Sao Paulo (Brazil)
2017-07-15
We present covariant quantization rules for nonsingular finite-dimensional classical theories with flat and curved configuration spaces. In the beginning, we construct a family of covariant quantizations in flat spaces and Cartesian coordinates. This family is parametrized by a function ω(θ), θ element of (1,0), which describes an ambiguity of the quantization. We generalize this construction presenting covariant quantizations of theories with flat configuration spaces but already with arbitrary curvilinear coordinates. Then we construct a so-called minimal family of covariant quantizations for theories with curved configuration spaces. This family of quantizations is parametrized by the same function ω(θ). Finally, we describe a more wide family of covariant quantizations in curved spaces. This family is already parametrized by two functions, the previous one ω(θ) and by an additional function Θ(x,ξ). The above mentioned minimal family is a part at Θ = 1 of the wide family of quantizations. We study constructed quantizations in detail, proving their consistency and covariance. As a physical application, we consider a quantization of a non-relativistic particle moving in a curved space, discussing the problem of a quantum potential. Applying the covariant quantizations in flat spaces to an old problem of constructing quantum Hamiltonian in polar coordinates, we directly obtain a correct result. (orig.)
Schlösser, Tom P C; van Stralen, Marijn; Chu, Winnie C W; Lam, Tsz-Ping; Ng, Bobby K W; Vincken, Koen L; Cheng, Jack C Y; Castelein, René M
2016-01-01
Although much attention has been given to the global three-dimensional aspect of adolescent idiopathic scoliosis (AIS), the accurate three-dimensional morphology of the primary and compensatory curves, as well as the intervening junctional segments, in the scoliotic spine has not been described before. A unique series of 77 AIS patients with high-resolution CT scans of the spine, acquired for surgical planning purposes, were included and compared to 22 healthy controls. Non-idiopathic curves were excluded. Endplate segmentation and local longitudinal axis in endplate plane enabled semi-automatic geometric analysis of the complete three-dimensional morphology of the spine, taking inter-vertebral rotation, intra-vertebral torsion and coronal and sagittal tilt into account. Intraclass correlation coefficients for interobserver reliability were 0.98-1.00. Coronal deviation, axial rotation and the exact length discrepancies in the reconstructed sagittal plane, as defined per vertebra and disc, were analyzed for each primary and compensatory curve as well as for the junctional segments in-between. The anterior-posterior difference of spinal length, based on "true" anterior and posterior points on endplates, was +3.8% for thoracic and +9.4% for (thoraco)lumbar curves, while the junctional segments were almost straight. This differed significantly from control group thoracic kyphosis (-4.1%; P<0.001) and lumbar lordosis (+7.8%; P<0.001). For all primary as well as compensatory curves, we observed linear correlations between the coronal Cobb angle, axial rotation and the anterior-posterior length difference (r≥0.729 for thoracic curves; r≥0.485 for (thoraco)lumbar curves). Excess anterior length of the spine in AIS has been described as a generalized growth disturbance, causing relative anterior spinal overgrowth. This study is the first to demonstrate that this anterior overgrowth is not a generalized phenomenon. It is confined to the primary as well as the
Point- and curve-based geometric conflation
Ló pez-Vá zquez, C.; Manso Callejo, M.A.
2013-01-01
Geometric conflation is the process undertaken to modify the coordinates of features in dataset A in order to match corresponding ones in dataset B. The overwhelming majority of the literature considers the use of points as features to define the transformation. In this article we present a procedure to consider one-dimensional curves also, which are commonly available as Global Navigation Satellite System (GNSS) tracks, routes, coastlines, and so on, in order to define the estimate of the displacements to be applied to each object in A. The procedure involves three steps, including the partial matching of corresponding curves, the computation of some analytical expression, and the addition of a correction term in order to satisfy basic cartographic rules. A numerical example is presented. © 2013 Copyright Taylor and Francis Group, LLC.
Directory of Open Access Journals (Sweden)
Je Hyun Baekt
2000-01-01
Full Text Available A numerical study is conducted on the fully-developed laminar flow of an incompressible viscous fluid in a square duct rotating about a perpendicular axis to the axial direction of the duct. At the straight duct, the rotation produces vortices due to the Coriolis force. Generally two vortex cells are formed and the axial velocity distribution is distorted by the effect of this Coriolis force. When a convective force is weak, two counter-rotating vortices are shown with a quasi-parabolic axial velocity profile for weak rotation rates. As the rotation rate increases, the axial velocity on the vertical centreline of the duct begins to flatten and the location of vorticity center is moved near to wall by the effect of the Coriolis force. When the convective inertia force is strong, a double-vortex secondary flow appears in the transverse planes of the duct for weak rotation rates but as the speed of rotation increases the secondary flow is shown to split into an asymmetric configuration of four counter-rotating vortices. If the rotation rates are increased further, the secondary flow restabilizes to a slightly asymmetric double-vortex configuration. Also, a numerical study is conducted on the laminar flow of an incompressible viscous fluid in a 90°-bend square duct that rotates about axis parallel to the axial direction of the inlet. At a 90°-bend square duct, the feature of flow by the effect of a Coriolis force and a centrifugal force, namely a secondary flow by the centrifugal force in the curved region and the Coriolis force in the downstream region, is shown since the centrifugal force in curved region and the Coriolis force in downstream region are dominant respectively.
Elliptic curves for applications (Tutorial)
Lange, T.; Bernstein, D.J.; Chatterjee, S.
2011-01-01
More than 25 years ago, elliptic curves over finite fields were suggested as a group in which the Discrete Logarithm Problem (DLP) can be hard. Since then many researchers have scrutinized the security of the DLP on elliptic curves with the result that for suitably chosen curves only exponential
Titration Curves: Fact and Fiction.
Chamberlain, John
1997-01-01
Discusses ways in which datalogging equipment can enable titration curves to be measured accurately and how computing power can be used to predict the shape of curves. Highlights include sources of error, use of spreadsheets to generate titration curves, titration of a weak acid with a strong alkali, dibasic acids, weak acid and weak base, and…
DEFF Research Database (Denmark)
Tatu, Aditya Jayant
This thesis deals with two unrelated issues, restricting curve evolution to subspaces and computing image patches in the equivalence class of Histogram of Gradient orientation based features using nonlinear projection methods. Curve evolution is a well known method used in various applications like...... tracking interfaces, active contour based segmentation methods and others. It can also be used to study shape spaces, as deforming a shape can be thought of as evolving its boundary curve. During curve evolution a curve traces out a path in the infinite dimensional space of curves. Due to application...... specific requirements like shape priors or a given data model, and due to limitations of the computer, the computed curve evolution forms a path in some finite dimensional subspace of the space of curves. We give methods to restrict the curve evolution to a finite dimensional linear or implicitly defined...
Properties of one-dimensional anharmonic lattice solitons
Szeftel, Jacob; Laurent-Gengoux, Pascal; Ilisca, Ernest; Hebbache, Mohamed
2000-12-01
The existence of bell- and kink-shaped solitons moving at constant velocity while keeping a permanent profile is studied in infinite periodic monoatomic chains of arbitrary anharmonicity by taking advantage of the equation of motion being integrable with respect to solitons. A second-order, non-linear differential equation involving advanced and retarded terms must be solved, which is done by implementing a scheme based on the finite element and Newton's methods. If the potential has a harmonic limit, the asymptotic time-decay behaves exponentially and there is a dispersion relation between propagation velocity and decay time. Inversely if the potential has no harmonic limit, the asymptotic regime shows up either as a power-law or faster than exponential. Excellent agreement is achieved with Toda's model. Illustrative examples are also given for the Fermi-Pasta-Ulam and sine-Gordon potentials. Owing to integrability an effective one-body potential is worked out in each case. Lattice and continuum solitons differ markedly from one another as regards the amplitude versus propagation velocity relationship and the asymptotic time behavior. The relevance of the linear stability analysis when applied to solitons propagating in an infinite crystal is questioned. The reasons preventing solitons from arising in a diatomic lattice are discussed.
Task 4 Improvised Nuclear Device Response Curves
Energy Technology Data Exchange (ETDEWEB)
Alai, Maureen [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Neuscamman, Stephanie [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2016-05-31
LLNL performed fallout and nuclear blast modeling for the 60 cities using the NARAC modeling system and predominant weather patterns determined in a previous Task 4 effort. LLNL performed model simulations and analyses to identify and provide response curves (expressed as two-dimensional contours) for radioactive fallout deposition, transport, population, and blast overpressure as a function of yield, weather, location and time. These contours can then be further combined and correlated with infrastructure and population databases to estimate city specific effects on KPFs such as impacted infrastructure and casualty rates.
Electron conductance in curved quantum structures
DEFF Research Database (Denmark)
Willatzen, Morten; Gravesen, Jens
2010-01-01
is computationally fast and provides direct (geometrical) parameter insight as regards the determination of the electron transmission coefficient. We present, as a case study, calculations of the electron conductivity of a helically shaped quantum-wire structure and discuss the influence of the quantum......A differential-geometry analysis is employed to investigate the transmission of electrons through a curved quantum-wire structure. Although the problem is a three-dimensional spatial problem, the Schrodinger equation can be separated into three general coordinates. Hence, the proposed method...
Directory of Open Access Journals (Sweden)
Sergey A. Cherkis
2007-03-01
Full Text Available A typical solution of an integrable system is described in terms of a holomorphic curve and a line bundle over it. The curve provides the action variables while the time evolution is a linear flow on the curve's Jacobian. Even though the system of Nahm equations is closely related to the Hitchin system, the curves appearing in these two cases have very different nature. The former can be described in terms of some classical scattering problem while the latter provides a solution to some Seiberg-Witten gauge theory. This note identifies the setup in which one can formulate the question of relating the two curves.
On the distribution of Weierstrass points on Gorenstein quintic curves
Directory of Open Access Journals (Sweden)
Kamel Alwaleed
2016-07-01
Full Text Available This paper is concerned with developing a technique to compute in a very precise way the distribution of Weierstrass points on the members of any 1-parameter family Ca, a∈C, of Gorenstein quintic curves with respect to the dualizing sheaf KCa. The nicest feature of the procedure is that it gives a way to produce examples of existence of Weierstrass points with prescribed special gap sequences, by looking at plane curves or, more generally, to subcanonical curves embedded in some higher dimensional projective space.
Nonequilibrium recombination after a curved shock wave
Wen, Chihyung; Hornung, Hans
2010-02-01
The effect of nonequilibrium recombination after a curved two-dimensional shock wave in a hypervelocity dissociating flow of an inviscid Lighthill-Freeman gas is considered. An analytical solution is obtained with the effective shock values derived by Hornung (1976) [5] and the assumption that the flow is ‘quasi-frozen’ after a thin dissociating layer near the shock. The solution gives the expression of dissociation fraction as a function of temperature on a streamline. A rule of thumb can then be provided to check the validity of binary scaling for experimental conditions and a tool to determine the limiting streamline that delineates the validity zone of binary scaling. The effects on the nonequilibrium chemical reaction of the large difference in free stream temperature between free-piston shock tunnel and equivalent flight conditions are discussed. Numerical examples are presented and the results are compared with solutions obtained with two-dimensional Euler equations using the code of Candler (1988) [10].
Energy Technology Data Exchange (ETDEWEB)
Calabri, L [CNR-INFM-National Research Center on nanoStructures and bioSystems at Surfaces (S3), Via Campi 213/a, 41100 Modena (Italy); Pugno, N [Department of Structural Engineering and Geotechnics, Politecnico di Torino, Turin (Italy); Ding, W [Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208-3111 (United States); Ruoff, R S [Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208-3111 (United States)
2006-08-23
The effects of non-ideal experimental configuration on the mechanical resonance of boron (B) nanowires (NWs) were studied to obtain the corrected value for the Young's modulus. The following effects have been theoretically considered: (i) the presence of intrinsic curvature (ii) non-ideal clamps (iii) spurious masses (iv) coating layer, and (v) large displacements. An energy-based analytical analysis was developed to treat such effects and their interactions. Here, we focus on treating the effect of the intrinsic curvature on the mechanical resonance. The analytical approach has been confirmed by numerical FEM analysis. A parallax method was used to obtain the three-dimensional geometry of the NW.
Johnson, L. E.; Kim, J.; Cifelli, R.; Chandra, C. V.
2016-12-01
Potential water retention, S, is one of parameters commonly used in hydrologic modeling for soil moisture accounting. Physically, S indicates total amount of water which can be stored in soil and is expressed in units of depth. S can be represented as a change of soil moisture content and in this context is commonly used to estimate direct runoff, especially in the Soil Conservation Service (SCS) curve number (CN) method. Generally, the lumped and the distributed hydrologic models can easily use the SCS-CN method to estimate direct runoff. Changes in potential water retention have been used in previous SCS-CN studies; however, these studies have focused on long-term hydrologic simulations where S is allowed to vary at the daily time scale. While useful for hydrologic events that span multiple days, the resolution is too coarse for short-term applications such as flash flood events where S may not recover its full potential. In this study, a new method for estimating a time-variable potential water retention at hourly time-scales is presented. The methodology is applied for the Napa River basin, California. The streamflow gage at St Helena, located in the upper reaches of the basin, is used as the control gage site to evaluate the model performance as it is has minimal influences by reservoirs and diversions. Rainfall events from 2011 to 2012 are used for estimating the event-based SCS CN to transfer to S. As a result, we have derived the potential water retention curve and it is classified into three sections depending on the relative change in S. The first is a negative slope section arising from the difference in the rate of moving water through the soil column, the second is a zero change section representing the initial recovery the potential water retention, and the third is a positive change section representing the full recovery of the potential water retention. Also, we found that the soil water moving has traffic jam within 24 hours after finished first
Energy Technology Data Exchange (ETDEWEB)
Lippoldt, Stefan
2016-01-21
In this thesis we study a formulation of Dirac fermions in curved spacetime that respects general coordinate invariance as well as invariance under local spin base transformations. We emphasize the advantages of the spin base invariant formalism both from a conceptual as well as from a practical viewpoint. This suggests that local spin base invariance should be added to the list of (effective) properties of (quantum) gravity theories. We find support for this viewpoint by the explicit construction of a global realization of the Clifford algebra on a 2-sphere which is impossible in the spin-base non-invariant vielbein formalism. The natural variables for this formulation are spacetime-dependent Dirac matrices subject to the Clifford-algebra constraint. In particular, a coframe, i.e. vielbein field is not required. We disclose the hidden spin base invariance of the vielbein formalism. Explicit formulas for the spin connection as a function of the Dirac matrices are found. This connection consists of a canonical part that is completely fixed in terms of the Dirac matrices and a free part that can be interpreted as spin torsion. The common Lorentz symmetric gauge for the vielbein is constructed for the Dirac matrices, even for metrics which are not linearly connected. Under certain criteria, it constitutes the simplest possible gauge, demonstrating why this gauge is so useful. Using the spin base formulation for building a field theory of quantized gravity and matter fields, we show that it suffices to quantize the metric and the matter fields. This observation is of particular relevance for field theory approaches to quantum gravity, as it can serve for a purely metric-based quantization scheme for gravity even in the presence of fermions. Hence, in the second part of this thesis we critically examine the gauge, and the field-parametrization dependence of renormalization group flows in the vicinity of non-Gaussian fixed points in quantum gravity. While physical
Optimization on shape curves with application to specular stereo
Balzer, Jonathan; Hö fer, Sebastian G.; Werling, Stefan; Beyerer, Jü rgen
2010-01-01
We state that a one-dimensional manifold of shapes in 3-space can be modeled by a level set function. Finding a minimizer of an independent functional among all points on such a shape curve has interesting applications in computer vision
Numerical investigation of Dean vortices in a curved pipe
Bernad, S. I.; Totorean, A.; Bosioc, A.; Stanciu, R.; Bernad, E. S.
2013-10-01
This study is devoted to the three-dimensional numerical simulation of developing secondary flows of Newtonian fluid through a curved circular duct. The numerical simulations produced for different Dean numbers show clearly the presence of two steady Dean vortices. Therefore, results confirm that helical flow constitutes an important flow signature in vessels, and its strength as a fluid dynamic index.
Sadek, Mohammad
2010-01-01
In this thesis we give insight into the minimisation problem of genus one curves defined by equations other than Weierstrass equations. We are interested in genus one curves given as double covers of P1, plane cubics, or complete intersections of two quadrics in P3. By minimising such a curve we mean making the invariants associated to its defining equations as small as possible using a suitable change of coordinates. We study the non-uniqueness of minimisations of the genus one curves des...
Shape optimization of self-avoiding curves
Walker, Shawn W.
2016-04-01
This paper presents a softened notion of proximity (or self-avoidance) for curves. We then derive a sensitivity result, based on shape differential calculus, for the proximity. This is combined with a gradient-based optimization approach to compute three-dimensional, parameterized curves that minimize the sum of an elastic (bending) energy and a proximity energy that maintains self-avoidance by a penalization technique. Minimizers are computed by a sequential-quadratic-programming (SQP) method where the bending energy and proximity energy are approximated by a finite element method. We then apply this method to two problems. First, we simulate adsorbed polymer strands that are constrained to be bound to a surface and be (locally) inextensible. This is a basic model of semi-flexible polymers adsorbed onto a surface (a current topic in material science). Several examples of minimizing curve shapes on a variety of surfaces are shown. An advantage of the method is that it can be much faster than using molecular dynamics for simulating polymer strands on surfaces. Second, we apply our proximity penalization to the computation of ideal knots. We present a heuristic scheme, utilizing the SQP method above, for minimizing rope-length and apply it in the case of the trefoil knot. Applications of this method could be for generating good initial guesses to a more accurate (but expensive) knot-tightening algorithm.
ESTIMATING TORSION OF DIGITAL CURVES USING 3D IMAGE ANALYSIS
Directory of Open Access Journals (Sweden)
Christoph Blankenburg
2016-04-01
Full Text Available Curvature and torsion of three-dimensional curves are important quantities in fields like material science or biomedical engineering. Torsion has an exact definition in the continuous domain. However, in the discrete case most of the existing torsion evaluation methods lead to inaccurate values, especially for low resolution data. In this contribution we use the discrete points of space curves to determine the Fourier series coefficients which allow for representing the underlying continuous curve with Cesàro’s mean. This representation of the curve suits for the estimation of curvature and torsion values with their classical continuous definition. In comparison with the literature, one major advantage of this approach is that no a priori knowledge about the shape of the cyclic curve parts approximating the discrete curves is required. Synthetic data, i.e. curves with known curvature and torsion, are used to quantify the inherent algorithm accuracy for torsion and curvature estimation. The algorithm is also tested on tomographic data of fiber structures and open foams, where discrete curves are extracted from the pore spaces.
International Nuclear Information System (INIS)
Carvalho-Santos, Vagson L.; Dandoloff, Rossen
2012-01-01
We study the nonlinear σ-model in an external magnetic field applied on curved surfaces with rotational symmetry. The Euler–Lagrange equations derived from the Hamiltonian yield the double sine-Gordon equation (DSG) provided the magnetic field is tuned with the curvature of the surface. A 2π skyrmion appears like a solution for this model and surface deformations are predicted at the sector where the spins point in the opposite direction to the magnetic field. We also study some specific examples by applying the model on three rotationally symmetric surfaces: the cylinder, the catenoid and the hyperboloid.
Quantum fields in curved space
International Nuclear Information System (INIS)
Birrell, N.D.; Davies, P.C.W.
1982-01-01
The book presents a comprehensive review of the subject of gravitational effects in quantum field theory. Quantum field theory in Minkowski space, quantum field theory in curved spacetime, flat spacetime examples, curved spacetime examples, stress-tensor renormalization, applications of renormalization techniques, quantum black holes and interacting fields are all discussed in detail. (U.K.)
Extended analysis of cooling curves
International Nuclear Information System (INIS)
Djurdjevic, M.B.; Kierkus, W.T.; Liliac, R.E.; Sokolowski, J.H.
2002-01-01
Thermal Analysis (TA) is the measurement of changes in a physical property of a material that is heated through a phase transformation temperature range. The temperature changes in the material are recorded as a function of the heating or cooling time in such a manner that allows for the detection of phase transformations. In order to increase accuracy, characteristic points on the cooling curve have been identified using the first derivative curve plotted versus time. In this paper, an alternative approach to the analysis of the cooling curve has been proposed. The first derivative curve has been plotted versus temperature and all characteristic points have been identified with the same accuracy achieved using the traditional method. The new cooling curve analysis also enables the Dendrite Coherency Point (DCP) to be detected using only one thermocouple. (author)
Rational points, rational curves, and entire holomorphic curves on projective varieties
Gasbarri, Carlo; Roth, Mike; Tschinkel, Yuri
2015-01-01
This volume contains papers from the Short Thematic Program on Rational Points, Rational Curves, and Entire Holomorphic Curves and Algebraic Varieties, held from June 3-28, 2013, at the Centre de Recherches Mathématiques, Université de Montréal, Québec, Canada. The program was dedicated to the study of subtle interconnections between geometric and arithmetic properties of higher-dimensional algebraic varieties. The main areas of the program were, among others, proving density of rational points in Zariski or analytic topology on special varieties, understanding global geometric properties of rationally connected varieties, as well as connections between geometry and algebraic dynamics exploring new geometric techniques in Diophantine approximation.
Head butting sheep: kink collisions in the presence of false vacua
International Nuclear Information System (INIS)
Ashcroft, Jennifer; Haberichter, Mareike; Eto, Minoru; Nitta, Muneto; Paranjape, M B
2016-01-01
We investigate numerically kink collisions in a 1 + 1 dimensional scalar field theory with multiple vacua. The domain wall model we are interested in involves two scalar fields and a potential term built from an asymmetric double well and (double) sine-Gordon potential together with an interaction term. Depending on the initial kink setup and impact velocities, the model allows for a wide range of scattering behaviours. Kinks can repel each other, annihilate, form true or false domain walls and reflect off each other. (paper)
A Novel Method for Detecting and Computing Univolatility Curves in Ternary Mixtures
DEFF Research Database (Denmark)
Shcherbakov, Nataliya; Rodriguez-Donis, Ivonne; Abildskov, Jens
2017-01-01
Residue curve maps (RCMs) and univolatility curves are crucial tools for analysis and design of distillation processes. Even in the case of ternary mixtures, the topology of these maps is highly non-trivial. We propose a novel method allowing detection and computation of univolatility curves...... of the generalized univolatility and unidistribution curves in the three dimensional composition – temperature state space lead to a simple and efficient algorithm of computation of the univolatility curves. Two peculiar ternary systems, namely diethylamine – chloroform – methanol and hexane – benzene...
Computational aspects of algebraic curves
Shaska, Tanush
2005-01-01
The development of new computational techniques and better computing power has made it possible to attack some classical problems of algebraic geometry. The main goal of this book is to highlight such computational techniques related to algebraic curves. The area of research in algebraic curves is receiving more interest not only from the mathematics community, but also from engineers and computer scientists, because of the importance of algebraic curves in applications including cryptography, coding theory, error-correcting codes, digital imaging, computer vision, and many more.This book cove
51Cr - erythrocyte survival curves
International Nuclear Information System (INIS)
Paiva Costa, J. de.
1982-07-01
Sixteen patients were studied, being fifteen patients in hemolytic state, and a normal individual as a witness. The aim was to obtain better techniques for the analysis of the erythrocytes, survival curves, according to the recommendations of the International Committee of Hematology. It was used the radiochromatic method as a tracer. Previously a revisional study of the International Literature was made in its aspects inherent to the work in execution, rendering possible to establish comparisons and clarify phonomena observed in cur investigation. Several parameters were considered in this study, hindering both the exponential and the linear curves. The analysis of the survival curves of the erythrocytes in the studied group, revealed that the elution factor did not present a homogeneous answer quantitatively to all, though, the result of the analysis of these curves have been established, through listed programs in the electronic calculator. (Author) [pt
Melting curves of gammairradiated DNA
International Nuclear Information System (INIS)
Hofer, H.; Altmann, H.; Kehrer, M.
1978-08-01
Melting curves of gammairradiated DNA and data derived of them, are reported. The diminished stability is explained by basedestruction. DNA denatures completely at room temperature, if at least every fifth basepair is broken or weakened by irradiation. (author)
Management of the learning curve
DEFF Research Database (Denmark)
Pedersen, Peter-Christian; Slepniov, Dmitrij
2016-01-01
Purpose – This paper focuses on the management of the learning curve in overseas capacity expansions. The purpose of this paper is to unravel the direct as well as indirect influences on the learning curve and to advance the understanding of how these affect its management. Design...... the dimensions of the learning process involved in a capacity expansion project and identified the direct and indirect labour influences on the production learning curve. On this basis, the study proposes solutions to managing learning curves in overseas capacity expansions. Furthermore, the paper concludes...... with measures that have the potential to significantly reduce the non-value-added time when establishing new capacities overseas. Originality/value – The paper uses a longitudinal in-depth case study of a Danish wind turbine manufacturer and goes beyond a simplistic treatment of the lead time and learning...
Growth curves for Laron syndrome.
Laron, Z; Lilos, P; Klinger, B
1993-01-01
Growth curves for children with Laron syndrome were constructed on the basis of repeated measurements made throughout infancy, childhood, and puberty in 24 (10 boys, 14 girls) of the 41 patients with this syndrome investigated in our clinic. Growth retardation was already noted at birth, the birth length ranging from 42 to 46 cm in the 12/20 available measurements. The postnatal growth curves deviated sharply from the normal from infancy on. Both sexes showed no clear pubertal spurt. Girls co...
Intersection numbers of spectral curves
Eynard, B.
2011-01-01
We compute the symplectic invariants of an arbitrary spectral curve with only 1 branchpoint in terms of integrals of characteristic classes in the moduli space of curves. Our formula associates to any spectral curve, a characteristic class, which is determined by the laplace transform of the spectral curve. This is a hint to the key role of Laplace transform in mirror symmetry. When the spectral curve is y=\\sqrt{x}, the formula gives Kontsevich--Witten intersection numbers, when the spectral curve is chosen to be the Lambert function \\exp{x}=y\\exp{-y}, the formula gives the ELSV formula for Hurwitz numbers, and when one chooses the mirror of C^3 with framing f, i.e. \\exp{-x}=\\exp{-yf}(1-\\exp{-y}), the formula gives the Marino-Vafa formula, i.e. the generating function of Gromov-Witten invariants of C^3. In some sense this formula generalizes ELSV, Marino-Vafa formula, and Mumford formula.
International Nuclear Information System (INIS)
Haverkamp, U.; Wiezorek, C.; Poetter, R.
1990-01-01
Lyoluminescence dosimetry is based upon light emission during dissolution of previously irradiated dosimetric materials. The lyoluminescence signal is expressed in the dissolution glow curve. These curves begin, depending on the dissolution system, with a high peak followed by an exponentially decreasing intensity. System parameters that influence the graph of the dissolution glow curve, are, for example, injection speed, temperature and pH value of the solution and the design of the dissolution cell. The initial peak does not significantly correlate with the absorbed dose, it is mainly an effect of the injection. The decay of the curve consists of two exponential components: one fast and one slow. The components depend on the absorbed dose and the dosimetric materials used. In particular, the slow component correlates with the absorbed dose. In contrast to the fast component the argument of the exponential function of the slow component is independent of the dosimetric materials investigated: trehalose, glucose and mannitol. The maximum value, following the peak of the curve, and the integral light output are a measure of the absorbed dose. The reason for the different light outputs of various dosimetric materials after irradiation with the same dose is the differing solubility. The character of the dissolution glow curves is the same following irradiation with photons, electrons or neutrons. (author)
p-y-ẏ curves for dynamic analysis of offshore wind turbine monopile foundations
DEFF Research Database (Denmark)
Bayat, Mehdi; Andersen, Lars Vabbersgaard; Ibsen, Lars Bo
2016-01-01
Highlights •A two-dimensional analysis of a monopile segment moving horizontally through saturated soil is analyzed. •A p−y−ẏ curve accounting for the rate of pile motion is proposed as an alternative to static p−y curves. •The stiffness and damping properties related to soil structure interaction...
A Method of Timbre-Shape Synthesis Based On Summation of Spherical Curves
DEFF Research Database (Denmark)
Putnam, Lance Jonathan
2014-01-01
It is well-known that there is a rich correspondence between sound and visual curves, perhaps most widely explored through direct input of sound into an oscilloscope. However, there have been relatively few proposals on how to translate sound into three-dimensional curves. We present a novel meth...
Analytical extension of curved shock theory
Emanuel, G.
2018-03-01
Curved shock theory (CST) is limited to shock waves in a steady, two-dimensional or axisymmetric (2-Ax) flow of a perfect gas. A unique feature of CST is its use of intrinsic coordinates that result in an elegant and useful formulation for flow properties just downstream of a shock. For instance, the downstream effect of upstream vorticity, shock wave curvature, and the upstream pressure gradient along a streamline is established. There have been several attempts to extend CST, as mentioned in the text. Removal of the steady, 2-Ax, and perfect gas limitations, singly or in combination, requires an appropriate formulation of the shock wave's jump relations and the intrinsic coordinate Euler equations. Issues discussed include flow plane versus osculating plane, unsteady flow, vorticity, an imperfect gas, etc. The extension of CST utilizes concepts from differential geometry, such as the osculating plane, streamline torsion, and the Serret-Frenet equations.
Zero-point field in curved spaces
International Nuclear Information System (INIS)
Hacyan, S.; Sarmiento, A.; Cocho, G.; Soto, F.
1985-01-01
Boyer's conjecture that the thermal effects of acceleration are manifestations of the zero-point field is further investigated within the context of quantum field theory in curved spaces. The energy-momentum current for a spinless field is defined rigorously and used as the basis for investigating the energy density observed in a noninertial frame. The following examples are considered: (i) uniformly accelerated observers, (ii) two-dimensional Schwarzschild black holes, (iii) the Einstein universe. The energy spectra which have been previously calculated appear in the present formalism as an additional contribution to the energy of the zero-point field, but particle creation does not occur. It is suggested that the radiation produced by gravitational fields or by acceleration is a manifestation of the zero-point field and of the same nature (whether real or virtual)
Curve Boxplot: Generalization of Boxplot for Ensembles of Curves.
Mirzargar, Mahsa; Whitaker, Ross T; Kirby, Robert M
2014-12-01
In simulation science, computational scientists often study the behavior of their simulations by repeated solutions with variations in parameters and/or boundary values or initial conditions. Through such simulation ensembles, one can try to understand or quantify the variability or uncertainty in a solution as a function of the various inputs or model assumptions. In response to a growing interest in simulation ensembles, the visualization community has developed a suite of methods for allowing users to observe and understand the properties of these ensembles in an efficient and effective manner. An important aspect of visualizing simulations is the analysis of derived features, often represented as points, surfaces, or curves. In this paper, we present a novel, nonparametric method for summarizing ensembles of 2D and 3D curves. We propose an extension of a method from descriptive statistics, data depth, to curves. We also demonstrate a set of rendering and visualization strategies for showing rank statistics of an ensemble of curves, which is a generalization of traditional whisker plots or boxplots to multidimensional curves. Results are presented for applications in neuroimaging, hurricane forecasting and fluid dynamics.
Optimization on shape curves with application to specular stereo
Balzer, Jonathan
2010-01-01
We state that a one-dimensional manifold of shapes in 3-space can be modeled by a level set function. Finding a minimizer of an independent functional among all points on such a shape curve has interesting applications in computer vision. It is shown how to replace the commonly encountered practice of gradient projection by a projection onto the curve itself. The outcome is an algorithm for constrained optimization, which, as we demonstrate theoretically and numerically, provides some important benefits in stereo reconstruction of specular surfaces. © 2010 Springer-Verlag.
Considerations for reference pump curves
International Nuclear Information System (INIS)
Stockton, N.B.
1992-01-01
This paper examines problems associated with inservice testing (IST) of pumps to assess their hydraulic performance using reference pump curves to establish acceptance criteria. Safety-related pumps at nuclear power plants are tested under the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (the Code), Section 11. The Code requires testing pumps at specific reference points of differential pressure or flow rate that can be readily duplicated during subsequent tests. There are many cases where test conditions cannot be duplicated. For some pumps, such as service water or component cooling pumps, the flow rate at any time depends on plant conditions and the arrangement of multiple independent and constantly changing loads. System conditions cannot be controlled to duplicate a specific reference value. In these cases, utilities frequently request to use pump curves for comparison of test data for acceptance. There is no prescribed method for developing a pump reference curve. The methods vary and may yield substantially different results. Some results are conservative when compared to the Code requirements; some are not. The errors associated with different curve testing techniques should be understood and controlled within reasonable bounds. Manufacturer's pump curves, in general, are not sufficiently accurate to use as reference pump curves for IST. Testing using reference curves generated with polynomial least squares fits over limited ranges of pump operation, cubic spline interpolation, or cubic spline least squares fits can provide a measure of pump hydraulic performance that is at least as accurate as the Code required method. Regardless of the test method, error can be reduced by using more accurate instruments, by correcting for systematic errors, by increasing the number of data points, and by taking repetitive measurements at each data point
Osserman, Robert
2011-01-01
The basic component of several-variable calculus, two-dimensional calculus is vital to mastery of the broader field. This extensive treatment of the subject offers the advantage of a thorough integration of linear algebra and materials, which aids readers in the development of geometric intuition. An introductory chapter presents background information on vectors in the plane, plane curves, and functions of two variables. Subsequent chapters address differentiation, transformations, and integration. Each chapter concludes with problem sets, and answers to selected exercises appear at the end o
Curve Digitizer – A software for multiple curves digitizing
Directory of Open Access Journals (Sweden)
Florentin ŞPERLEA
2010-06-01
Full Text Available The Curve Digitizer is software that extracts data from an image file representing a graphicand returns them as pairs of numbers which can then be used for further analysis and applications.Numbers can be read on a computer screen stored in files or copied on paper. The final result is adata set that can be used with other tools such as MSEXCEL. Curve Digitizer provides a useful toolfor any researcher or engineer interested in quantifying the data displayed graphically. The image filecan be obtained by scanning a document
Path Integrals and Anomalies in Curved Space
International Nuclear Information System (INIS)
Louko, Jorma
2007-01-01
Bastianelli and van Nieuwenhuizen's monograph 'Path Integrals and Anomalies in Curved Space' collects in one volume the results of the authors' 15-year research programme on anomalies that arise in Feynman diagrams of quantum field theories on curved manifolds. The programme was spurred by the path-integral techniques introduced in Alvarez-Gaume and Witten's renowned 1983 paper on gravitational anomalies which, together with the anomaly cancellation paper by Green and Schwarz, led to the string theory explosion of the 1980s. The authors have produced a tour de force, giving a comprehensive and pedagogical exposition of material that is central to current research. The first part of the book develops from scratch a formalism for defining and evaluating quantum mechanical path integrals in nonlinear sigma models, using time slicing regularization, mode regularization and dimensional regularization. The second part applies this formalism to quantum fields of spin 0, 1/2, 1 and 3/2 and to self-dual antisymmetric tensor fields. The book concludes with a discussion of gravitational anomalies in 10-dimensional supergravities, for both classical and exceptional gauge groups. The target audience is researchers and graduate students in curved spacetime quantum field theory and string theory, and the aims, style and pedagogical level have been chosen with this audience in mind. Path integrals are treated as calculational tools, and the notation and terminology are throughout tailored to calculational convenience, rather than to mathematical rigour. The style is closer to that of an exceedingly thorough and self-contained review article than to that of a textbook. As the authors mention, the first part of the book can be used as an introduction to path integrals in quantum mechanics, although in a classroom setting perhaps more likely as supplementary reading than a primary class text. Readers outside the core audience, including this reviewer, will gain from the book a
Multi-q pattern classification of polarization curves
Fabbri, Ricardo; Bastos, Ivan N.; Neto, Francisco D. Moura; Lopes, Francisco J. P.; Gonçalves, Wesley N.; Bruno, Odemir M.
2014-02-01
Several experimental measurements are expressed in the form of one-dimensional profiles, for which there is a scarcity of methodologies able to classify the pertinence of a given result to a specific group. The polarization curves that evaluate the corrosion kinetics of electrodes in corrosive media are applications where the behavior is chiefly analyzed from profiles. Polarization curves are indeed a classic method to determine the global kinetics of metallic electrodes, but the strong nonlinearity from different metals and alloys can overlap and the discrimination becomes a challenging problem. Moreover, even finding a typical curve from replicated tests requires subjective judgment. In this paper, we used the so-called multi-q approach based on the Tsallis statistics in a classification engine to separate the multiple polarization curve profiles of two stainless steels. We collected 48 experimental polarization curves in an aqueous chloride medium of two stainless steel types, with different resistance against localized corrosion. Multi-q pattern analysis was then carried out on a wide potential range, from cathodic up to anodic regions. An excellent classification rate was obtained, at a success rate of 90%, 80%, and 83% for low (cathodic), high (anodic), and both potential ranges, respectively, using only 2% of the original profile data. These results show the potential of the proposed approach towards efficient, robust, systematic and automatic classification of highly nonlinear profile curves.
DECIPHERING THERMAL PHASE CURVES OF DRY, TIDALLY LOCKED TERRESTRIAL PLANETS
Energy Technology Data Exchange (ETDEWEB)
Koll, Daniel D. B.; Abbot, Dorian S., E-mail: dkoll@uchicago.edu [Department of the Geophysical Sciences, University of Chicago, Chicago, IL 60637 (United States)
2015-03-20
Next-generation space telescopes will allow us to characterize terrestrial exoplanets. To do so effectively it will be crucial to make use of all available data. We investigate which atmospheric properties can, and cannot, be inferred from the broadband thermal phase curve of a dry and tidally locked terrestrial planet. First, we use dimensional analysis to show that phase curves are controlled by six nondimensional parameters. Second, we use an idealized general circulation model to explore the relative sensitivity of phase curves to these parameters. We find that the feature of phase curves most sensitive to atmospheric parameters is the peak-to-trough amplitude. Moreover, except for hot and rapidly rotating planets, the phase amplitude is primarily sensitive to only two nondimensional parameters: (1) the ratio of dynamical to radiative timescales and (2) the longwave optical depth at the surface. As an application of this technique, we show how phase curve measurements can be combined with transit or emission spectroscopy to yield a new constraint for the surface pressure and atmospheric mass of terrestrial planets. We estimate that a single broadband phase curve, measured over half an orbit with the James Webb Space Telescope, could meaningfully constrain the atmospheric mass of a nearby super-Earth. Such constraints will be important for studying the atmospheric evolution of terrestrial exoplanets as well as characterizing the surface conditions on potentially habitable planets.
Calibration curves for biological dosimetry
International Nuclear Information System (INIS)
Guerrero C, C.; Brena V, M. . E-mail cgc@nuclear.inin.mx
2004-01-01
The generated information by the investigations in different laboratories of the world, included the ININ, in which settles down that certain class of chromosomal leisure it increases in function of the dose and radiation type, has given by result the obtaining of calibrated curves that are applied in the well-known technique as biological dosimetry. In this work is presented a summary of the work made in the laboratory that includes the calibrated curves for gamma radiation of 60 Cobalt and X rays of 250 k Vp, examples of presumed exposure to ionizing radiation, resolved by means of aberration analysis and the corresponding dose estimate through the equations of the respective curves and finally a comparison among the dose calculations in those people affected by the accident of Ciudad Juarez, carried out by the group of Oak Ridge, USA and those obtained in this laboratory. (Author)
Curve collection, extension of databases
International Nuclear Information System (INIS)
Gillemot, F.
1992-01-01
Full text: Databases: generally calculated data only. The original measurements: diagrams. Information loss between them Expensive research eg. irradiation, aging, creep etc. Original curves should be stored for reanalysing. The format of the stored curves: a. Data in ASCII files, only numbers b. Other information in strings in a second file Same name, but different extension. Extensions shows the type of the test and the type of the file. EXAMPLES. TEN is tensile information, TED is tensile data, CHN is Charpy informations, CHD is Charpy data. Storing techniques: digitalised measurements, digitalising old curves stored on paper. Use: making catalogues, reanalysing, comparison with new data. Tools: mathematical software packages like quattro, genplot, exel, mathcad, qbasic, pascal, fortran, mathlab, grapher etc. (author)
Rational points on elliptic curves
Silverman, Joseph H
2015-01-01
The theory of elliptic curves involves a pleasing blend of algebra, geometry, analysis, and number theory. This book stresses this interplay as it develops the basic theory, thereby providing an opportunity for advanced undergraduates to appreciate the unity of modern mathematics. At the same time, every effort has been made to use only methods and results commonly included in the undergraduate curriculum. This accessibility, the informal writing style, and a wealth of exercises make Rational Points on Elliptic Curves an ideal introduction for students at all levels who are interested in learning about Diophantine equations and arithmetic geometry. Most concretely, an elliptic curve is the set of zeroes of a cubic polynomial in two variables. If the polynomial has rational coefficients, then one can ask for a description of those zeroes whose coordinates are either integers or rational numbers. It is this number theoretic question that is the main subject of this book. Topics covered include the geometry and ...
Theoretical melting curve of caesium
International Nuclear Information System (INIS)
Simozar, S.; Girifalco, L.A.; Pennsylvania Univ., Philadelphia
1983-01-01
A statistical-mechanical model is developed to account for the complex melting curve of caesium. The model assumes the existence of three different species of caesium defined by three different electronic states. On the basis of this model, the free energy of melting and the melting curve are computed up to 60 kbar, using the solid-state data and the initial slope of the fusion curve as input parameters. The calculated phase diagram agrees with experiment to within the experimental error. Other thermodynamic properties including the entropy and volume of melting were also computed, and they agree with experiment. Since the theory requires only one adjustable constant, this is taken as strong evidence that the three-species model is satisfactory for caesium. (author)
DEFF Research Database (Denmark)
Brücker, Herbert; Jahn, Elke J.
in a general equilibrium framework. For the empirical analysis we employ the IABS, a two percent sample of the German labor force. We find that the elasticity of the wage curve is particularly high for young workers and workers with a university degree, while it is low for older workers and workers...... Based on a wage curve approach we examine the labor market effects of migration in Germany. The wage curve relies on the assumption that wages respond to a change in the unemployment rate, albeit imperfectly. This allows one to derive the wage and employment effects of migration simultaneously...... with a vocational degree. The wage and employment effects of migration are moderate: a 1 percent increase in the German labor force through immigration increases the aggregate unemployment rate by less than 0.1 percentage points and reduces average wages by less 0.1 percent. While native workers benefit from...
Laffer Curves and Home Production
Directory of Open Access Journals (Sweden)
Kotamäki Mauri
2017-06-01
Full Text Available In the earlier related literature, consumption tax rate Laffer curve is found to be strictly increasing (see Trabandt and Uhlig (2011. In this paper, a general equilibrium macro model is augmented by introducing a substitute for private consumption in the form of home production. The introduction of home production brings about an additional margin of adjustment – an increase in consumption tax rate not only decreases labor supply and reduces the consumption tax base but also allows a substitution of market goods with home-produced goods. The main objective of this paper is to show that, after the introduction of home production, the consumption tax Laffer curve exhibits an inverse U-shape. Also the income tax Laffer curves are significantly altered. The result shown in this paper casts doubt on some of the earlier results in the literature.
Complexity of Curved Glass Structures
Kosić, T.; Svetel, I.; Cekić, Z.
2017-11-01
Despite the increasing number of research on the architectural structures of curvilinear forms and technological and practical improvement of the glass production observed over recent years, there is still a lack of comprehensive codes and standards, recommendations and experience data linked to real-life curved glass structures applications regarding design, manufacture, use, performance and economy. However, more and more complex buildings and structures with the large areas of glass envelope geometrically complex shape are built every year. The aim of the presented research is to collect data on the existing design philosophy on curved glass structure cases. The investigation includes a survey about how architects and engineers deal with different design aspects of curved glass structures with a special focus on the design and construction process, glass types and structural and fixing systems. The current paper gives a brief overview of the survey findings.
Closed timelike curves in asymmetrically warped brane universes
Päs, Heinrich; Pakvasa, Sandip; Dent, James; Weiler, Thomas J.
2009-08-01
In asymmetrically-warped spacetimes different warp factors are assigned to space and to time. We discuss causality properties of these warped brane universes and argue that scenarios with two extra dimensions may allow for timelike curves which can be closed via paths in the extra-dimensional bulk. In particular, necessary and sufficient conditions on the metric for the existence of closed timelike curves are presented. We find a six-dimensional warped metric which satisfies the CTC conditions, and where the null, weak and dominant energy conditions are satisfied on the brane (although only the former remains satisfied in the bulk). Such scenarios are interesting, since they open the possibility of experimentally testing the chronology protection conjecture by manipulating on our brane initial conditions of gravitons or hypothetical gauge-singlet fermions (“sterile neutrinos”) which then propagate in the extra dimensions.
Optimization on Spaces of Curves
DEFF Research Database (Denmark)
Møller-Andersen, Jakob
in Rd, and methods to solve the initial and boundary value problem for geodesics allowing us to compute the Karcher mean and principal components analysis of data of curves. We apply the methods to study shape variation in synthetic data in the Kimia shape database, in HeLa cell nuclei and cycles...... of cardiac deformations. Finally we investigate a new application of Riemannian shape analysis in shape optimization. We setup a simple elliptic model problem, and describe how to apply shape calculus to obtain directional derivatives in the manifold of planar curves. We present an implementation based...
Tracing a planar algebraic curve
International Nuclear Information System (INIS)
Chen Falai; Kozak, J.
1994-09-01
In this paper, an algorithm that determines a real algebraic curve is outlined. Its basic step is to divide the plane into subdomains that include only simple branches of the algebraic curve without singular points. Each of the branches is then stably and efficiently traced in the particular subdomain. Except for the tracing, the algorithm requires only a couple of simple operations on polynomials that can be carried out exactly if the coefficients are rational, and the determination of zeros of several polynomials of one variable. (author). 5 refs, 4 figs
The New Keynesian Phillips Curve
DEFF Research Database (Denmark)
Ólafsson, Tjörvi
This paper provides a survey on the recent literature on the new Keynesian Phillips curve: the controversies surrounding its microfoundation and estimation, the approaches that have been tried to improve its empirical fit and the challenges it faces adapting to the open-economy framework. The new......, learning or state-dependant pricing. The introduction of openeconomy factors into the new Keynesian Phillips curve complicate matters further as it must capture the nexus between price setting, inflation and the exchange rate. This is nevertheless a crucial feature for any model to be used for inflation...... forecasting in a small open economy like Iceland....
Maxwell-Chern-Simons theory for curved spacetime backgrounds
International Nuclear Information System (INIS)
Kant, E.; Klinkhamer, F.R.
2005-01-01
We consider a modified version of four-dimensional electrodynamics, which has a photonic Chern-Simons-like term with spacelike background vector in the action. Light propagation in curved spacetime backgrounds is discussed using the geometrical-optics approximation. The corresponding light path is modified, which allows for new effects. In a Schwarzschild background, for example, there now exist stable bounded orbits of light rays and the two polarization modes of light rays in unbounded orbits can have different gravitational redshifts
Generalized Hitchin system, spectral curve and N=1 dynamics
Energy Technology Data Exchange (ETDEWEB)
Xie, Dan; Yonekura, Kazuya [School of Natural Sciences, Institute for Advanced Study,1 Einstein Drive, Princeton, NJ 08540 (United States)
2014-01-02
A generalized Hitchin equation was proposed as the BPS equation for a large class of four dimensional N=1 theories engineered using M5 branes. In this paper, we show how to write down the spectral curve for the moduli space of generalized Hitchin equations, and extract interesting N=1 dynamics out of it, such as deformed modui space, chiral ring relation, SUSY breaking, etc. Holomorphy plays a crucial role in our construction.
Dual Smarandache Curves of a Timelike Curve lying on Unit dual Lorentzian Sphere
Kahraman, Tanju; Hüseyin Ugurlu, Hasan
2016-01-01
In this paper, we give Darboux approximation for dual Smarandache curves of time like curve on unit dual Lorentzian sphere. Firstly, we define the four types of dual Smarandache curves of a timelike curve lying on dual Lorentzian sphere.
Electro-Mechanical Resonance Curves
Greenslade, Thomas B., Jr.
2018-01-01
Recently I have been investigating the frequency response of galvanometers. These are direct-current devices used to measure small currents. By using a low-frequency function generator to supply the alternating-current signal and a stopwatch smartphone app to measure the period, I was able to take data to allow a resonance curve to be drawn. This…
2013-01-01
This software can be used to assist with the assessment of margin of safety for a horizontal curve. It is intended for use by engineers and technicians responsible for safety analysis or management of rural highway pavement or traffic control devices...
Principal Curves on Riemannian Manifolds.
Hauberg, Soren
2016-09-01
Euclidean statistics are often generalized to Riemannian manifolds by replacing straight-line interpolations with geodesic ones. While these Riemannian models are familiar-looking, they are restricted by the inflexibility of geodesics, and they rely on constructions which are optimal only in Euclidean domains. We consider extensions of Principal Component Analysis (PCA) to Riemannian manifolds. Classic Riemannian approaches seek a geodesic curve passing through the mean that optimizes a criteria of interest. The requirements that the solution both is geodesic and must pass through the mean tend to imply that the methods only work well when the manifold is mostly flat within the support of the generating distribution. We argue that instead of generalizing linear Euclidean models, it is more fruitful to generalize non-linear Euclidean models. Specifically, we extend the classic Principal Curves from Hastie & Stuetzle to data residing on a complete Riemannian manifold. We show that for elliptical distributions in the tangent of spaces of constant curvature, the standard principal geodesic is a principal curve. The proposed model is simple to compute and avoids many of the pitfalls of traditional geodesic approaches. We empirically demonstrate the effectiveness of the Riemannian principal curves on several manifolds and datasets.
Elliptic curves and primality proving
Atkin, A. O. L.; Morain, F.
1993-07-01
The aim of this paper is to describe the theory and implementation of the Elliptic Curve Primality Proving algorithm. Problema, numeros primos a compositis dignoscendi, hosque in factores suos primos resolvendi, ad gravissima ac utilissima totius arithmeticae pertinere, et geometrarum tum veterum tum recentiorum industriam ac sagacitatem occupavisse, tam notum est, ut de hac re copiose loqui superfluum foret.
Indian Academy of Sciences (India)
from biology, feel that every pattern in the living world, ranging from the folding of ... curves band c have the same rate of increase but reach different asymptotes. If these .... not at x = 0, but at xo' which is the minimum size at birth that will permit ...
Survival curves for irradiated cells
International Nuclear Information System (INIS)
Gibson, D.K.
1975-01-01
The subject of the lecture is the probability of survival of biological cells which have been subjected to ionising radiation. The basic mathematical theories of cell survival as a function of radiation dose are developed. A brief comparison with observed survival curves is made. (author)
Mentorship, learning curves, and balance.
Cohen, Meryl S; Jacobs, Jeffrey P; Quintessenza, James A; Chai, Paul J; Lindberg, Harald L; Dickey, Jamie; Ungerleider, Ross M
2007-09-01
Professionals working in the arena of health care face a variety of challenges as their careers evolve and develop. In this review, we analyze the role of mentorship, learning curves, and balance in overcoming challenges that all such professionals are likely to encounter. These challenges can exist both in professional and personal life. As any professional involved in health care matures, complex professional skills must be mastered, and new professional skills must be acquired. These skills are both technical and judgmental. In most circumstances, these skills must be learned. In 2007, despite the continued need for obtaining new knowledge and learning new skills, the professional and public tolerance for a "learning curve" is much less than in previous decades. Mentorship is the key to success in these endeavours. The success of mentorship is two-sided, with responsibilities for both the mentor and the mentee. The benefits of this relationship must be bidirectional. It is the responsibility of both the student and the mentor to assure this bidirectional exchange of benefit. This relationship requires time, patience, dedication, and to some degree selflessness. This mentorship will ultimately be the best tool for mastering complex professional skills and maturing through various learning curves. Professional mentorship also requires that mentors identify and explicitly teach their mentees the relational skills and abilities inherent in learning the management of the triad of self, relationships with others, and professional responsibilities.Up to two decades ago, a learning curve was tolerated, and even expected, while professionals involved in healthcare developed the techniques that allowed for the treatment of previously untreatable diseases. Outcomes have now improved to the point that this type of learning curve is no longer acceptable to the public. Still, professionals must learn to perform and develop independence and confidence. The responsibility to
Comparison of two methods to determine fan performance curves using computational fluid dynamics
Onma, Patinya; Chantrasmi, Tonkid
2018-01-01
This work investigates a systematic numerical approach that employs Computational Fluid Dynamics (CFD) to obtain performance curves of a backward-curved centrifugal fan. Generating the performance curves requires a number of three-dimensional simulations with varying system loads at a fixed rotational speed. Two methods were used and their results compared to experimental data. The first method incrementally changes the mass flow late through the inlet boundary condition while the second method utilizes a series of meshes representing the physical damper blade at various angles. The generated performance curves from both methods are compared with an experiment setup in accordance with the AMCA fan performance testing standard.
A catalog of special plane curves
Lawrence, J Dennis
2014-01-01
Among the largest, finest collections available-illustrated not only once for each curve, but also for various values of any parameters present. Covers general properties of curves and types of derived curves. Curves illustrated by a CalComp digital incremental plotter. 12 illustrations.
Computation of undulator tuning curves
International Nuclear Information System (INIS)
Dejus, Roger J.
1997-01-01
Computer codes for fast computation of on-axis brilliance tuning curves and flux tuning curves have been developed. They are valid for an ideal device (regular planar device or a helical device) using the Bessel function formalism. The effects of the particle beam emittance and the beam energy spread on the spectrum are taken into account. The applicability of the codes and the importance of magnetic field errors of real insertion devices are addressed. The validity of the codes has been experimentally verified at the APS and observed discrepancies are in agreement with predicted reduction of intensities due to magnetic field errors. The codes are distributed as part of the graphical user interface XOP (X-ray OPtics utilities), which simplifies execution and viewing of the results
Curved canals: Ancestral files revisited
Directory of Open Access Journals (Sweden)
Jain Nidhi
2008-01-01
Full Text Available The aim of this article is to provide an insight into different techniques of cleaning and shaping of curved root canals with hand instruments. Although a plethora of root canal instruments like ProFile, ProTaper, LightSpeed ® etc dominate the current scenario, the inexpensive conventional root canal hand files such as K-files and flexible files can be used to get optimum results when handled meticulously. Special emphasis has been put on the modifications in biomechanical canal preparation in a variety of curved canal cases. This article compiles a series of clinical cases of root canals with curvatures in the middle and apical third and with S-shaped curvatures that were successfully completed by employing only conventional root canal hand instruments.
Curved Folded Plate Timber Structures
Buri, Hans Ulrich; Stotz, Ivo; Weinand, Yves
2011-01-01
This work investigates the development of a Curved Origami Prototype made with timber panels. In the last fifteen years the timber industry has developed new, large size, timber panels. Composition and dimensions of these panels and the possibility of milling them with Computer Numerical Controlled machines shows great potential for folded plate structures. To generate the form of these structures we were inspired by Origami, the Japanese art of paper folding. Common paper tessellations are c...
Growth curves for Laron syndrome.
Laron, Z; Lilos, P; Klinger, B
1993-01-01
Growth curves for children with Laron syndrome were constructed on the basis of repeated measurements made throughout infancy, childhood, and puberty in 24 (10 boys, 14 girls) of the 41 patients with this syndrome investigated in our clinic. Growth retardation was already noted at birth, the birth length ranging from 42 to 46 cm in the 12/20 available measurements. The postnatal growth curves deviated sharply from the normal from infancy on. Both sexes showed no clear pubertal spurt. Girls completed their growth between the age of 16-19 years to a final mean (SD) height of 119 (8.5) cm whereas the boys continued growing beyond the age of 20 years, achieving a final height of 124 (8.5) cm. At all ages the upper to lower body segment ratio was more than 2 SD above the normal mean. These growth curves constitute a model not only for primary, hereditary insulin-like growth factor-I (IGF-I) deficiency (Laron syndrome) but also for untreated secondary IGF-I deficiencies such as growth hormone gene deletion and idiopathic congenital isolated growth hormone deficiency. They should also be useful in the follow up of children with Laron syndrome treated with biosynthetic recombinant IGF-I. PMID:8333769
Elementary particles in curved spaces
International Nuclear Information System (INIS)
Lazanu, I.
2004-01-01
The theories in particle physics are developed currently, in Minkowski space-time starting from the Poincare group. A physical theory in flat space can be seen as the limit of a more general physical theory in a curved space. At the present time, a theory of particles in curved space does not exist, and thus the only possibility is to extend the existent theories in these spaces. A formidable obstacle to the extension of physical models is the absence of groups of motion in more general Riemann spaces. A space of constant curvature has a group of motion that, although differs from that of a flat space, has the same number of parameters and could permit some generalisations. In this contribution we try to investigate some physical implications of the presumable existence of elementary particles in curved space. In de Sitter space (dS) the invariant rest mass is a combination of the Poincare rest mass and the generalised angular momentum of a particle and it permits to establish a correlation with the vacuum energy and with the cosmological constant. The consequences are significant because in an experiment the local structure of space-time departs from the Minkowski space and becomes a dS or AdS space-time. Discrete symmetry characteristics of the dS/AdS group suggest some arguments for the possible existence of the 'mirror matter'. (author)
Statistical properties of curved polymer
Indian Academy of Sciences (India)
respective ground states decide the conformational statistics of the polymer. For semiflexible polymers, the relevant non-dimensional quantity is lp/L, where lp is the persistence length (which is proportional to the bending modulus k) and L is the contour length of the polymer. In the limit, lp/L ≪ 1, the polymer behaves as.
Dual Smarandache Curves and Smarandache Ruled Surfaces
Tanju KAHRAMAN; Mehmet ÖNDER; H. Hüseyin UGURLU
2013-01-01
In this paper, by considering dual geodesic trihedron (dual Darboux frame) we define dual Smarandache curves lying fully on dual unit sphere S^2 and corresponding to ruled surfaces. We obtain the relationships between the elements of curvature of dual spherical curve (ruled surface) x(s) and its dual Smarandache curve (Smarandache ruled surface) x1(s) and we give an example for dual Smarandache curves of a dual spherical curve.
International Nuclear Information System (INIS)
Matijevič, Gal; Prša, Andrej; Orosz, Jerome A.; Welsh, William F.; Bloemen, Steven; Barclay, Thomas
2012-01-01
We present an automated classification of 2165 Kepler eclipsing binary (EB) light curves that accompanied the second Kepler data release. The light curves are classified using locally linear embedding, a general nonlinear dimensionality reduction tool, into morphology types (detached, semi-detached, overcontact, ellipsoidal). The method, related to a more widely used principal component analysis, produces a lower-dimensional representation of the input data while preserving local geometry and, consequently, the similarity between neighboring data points. We use this property to reduce the dimensionality in a series of steps to a one-dimensional manifold and classify light curves with a single parameter that is a measure of 'detachedness' of the system. This fully automated classification correlates well with the manual determination of morphology from the data release, and also efficiently highlights any misclassified objects. Once a lower-dimensional projection space is defined, the classification of additional light curves runs in a negligible time and the method can therefore be used as a fully automated classifier in pipeline structures. The classifier forms a tier of the Kepler EB pipeline that pre-processes light curves for the artificial intelligence based parameter estimator.
International Nuclear Information System (INIS)
Nastase, Horatiu; Stephanov, Misha; Nieuwenhuizen, Peter van; Rebhan, Anton
1999-01-01
We fix the long-standing ambiguity in the one-loop contribution to the mass of a 1 + 1-dimensional supersymmetric soliton by adopting a set of boundary conditions which follow from the symmetries of the action and which depend only on the topology of the sector considered, and by invoking a physical principle that ought to hold generally in quantum field theories with a topological sector: for vanishing mass and other dimensionful constants, the vacuum energies in the trivial and topological sectors have to become equal. In the two-dimensional N = 1 supersymmetric case we find a result which for the supersymmetric sine-Gordon model agrees with the known exact solution of the S-matrix but seems to violate the BPS bound. We analyze the non-trivial relation between the quantum soliton mass and the quantum BPS bound and find a resolution. For N = 2 supersymmetric theories, there are no one-loop corrections to the soliton mass and to the central charge (and also no ambiguities) so that the BPS bound is always saturated. Beyond one-loop there are no ambiguities in any theory, which we explicitly check by a two-loop calculation in the sine-Gordon model
On non-equilibrium states in QFT model with boundary interaction
International Nuclear Information System (INIS)
Bazhanov, Vladimir V.; Lukyanov, Sergei L.; Zamolodchikov, Alexander B.
1999-01-01
We prove that certain non-equilibrium expectation values in the boundary sine-Gordon model coincide with associated equilibrium-state expectation values in the systems which differ from the boundary sine-Gordon in that certain extra boundary degrees of freedom (q-oscillators) are added. Applications of this result to actual calculation of non-equilibrium characteristics of the boundary sine-Gordon model are also discussed
A note on families of fragility curves
International Nuclear Information System (INIS)
Kaplan, S.; Bier, V.M.; Bley, D.C.
1989-01-01
In the quantitative assessment of seismic risk, uncertainty in the fragility of a structural component is usually expressed by putting forth a family of fragility curves, with probability serving as the parameter of the family. Commonly, a lognormal shape is used both for the individual curves and for the expression of uncertainty over the family. A so-called composite single curve can also be drawn and used for purposes of approximation. This composite curve is often regarded as equivalent to the mean curve of the family. The equality seems intuitively reasonable, but according to the authors has never been proven. The paper presented proves this equivalence hypothesis mathematically. Moreover, the authors show that this equivalence hypothesis between fragility curves is itself equivalent to an identity property of the standard normal probability curve. Thus, in the course of proving the fragility curve hypothesis, the authors have also proved a rather obscure, but interesting and perhaps previously unrecognized, property of the standard normal curve
Indian Academy of Sciences (India)
Dimensional analysis is a useful tool which finds important applications in physics and engineering. It is most effective when there exist a maximal number of dimensionless quantities constructed out of the relevant physical variables. Though a complete theory of dimen- sional analysis was developed way back in 1914 in a.
Tachyon condensation on the elliptic curve
International Nuclear Information System (INIS)
Govindarajan, Suresh; Jockers, Hans; Lerche, Wolfgang; Warner, Nicholas P.
2007-01-01
We use the framework of matrix factorizations to study topological B-type D-branes on the cubic curve. Specifically, we elucidate how the brane RR charges are encoded in the matrix factors, by analyzing their structure in terms of sections of vector bundles in conjunction with equivariant R-symmetry. One particular advantage of matrix factorizations is that explicit moduli dependence is built in, thus giving us full control over the open-string moduli space. It allows one to study phenomena like discontinuous jumps of the cohomology over the moduli space, as well as formation of bound states at threshold. One interesting aspect is that certain gauge symmetries inherent to the matrix formulation lead to a non-trivial global structure of the moduli space. We also investigate topological tachyon condensation, which enables us to construct, in a systematic fashion, higher-dimensional matrix factorizations out of smaller ones; this amounts to obtaining branes with higher RR charges as composites of ones with minimal charges. As an application, we explicitly construct all rank two matrix factorizations
Tachyon Condensation on the Elliptic Curve
Govindarajan, S; Lerche, Wolfgang; Warner, Nicholas P
2007-01-01
We use the framework of matrix factorizations to study topological B-type D-branes on the cubic curve. Specifically, we elucidate how the brane RR charges are encoded in the matrix factors, by analyzing their structure in terms of sections of vector bundles in conjunction with equivariant R-symmetry. One particular advantage of matrix factorizations is that explicit moduli dependence is built in, thus giving us full control over the open-string moduli space. It allows one to study phenomena like discontinuous jumps of the cohomology over the moduli space, as well as formation of bound states at threshold. One interesting aspect is that certain gauge symmetries inherent to the matrix formulation lead to a non-trivial global structure of the moduli space. We also investigate topological tachyon condensation, which enables us to construct, in a systematic fashion, higher-dimensional matrix factorizations out of smaller ones; this amounts to obtaining branes with higher RR charges as composites of ones with minim...
Observable Zitterbewegung in curved spacetimes
Kobakhidze, Archil; Manning, Adrian; Tureanu, Anca
2016-06-01
Zitterbewegung, as it was originally described by Schrödinger, is an unphysical, non-observable effect. We verify whether the effect can be observed in non-inertial reference frames/curved spacetimes, where the ambiguity in defining particle states results in a mixing of positive and negative frequency modes. We explicitly demonstrate that such a mixing is in fact necessary to obtain the correct classical value for a particle's velocity in a uniformly accelerated reference frame, whereas in cosmological spacetime a particle does indeed exhibit Zitterbewegung.
Observable Zitterbewegung in curved spacetimes
Energy Technology Data Exchange (ETDEWEB)
Kobakhidze, Archil, E-mail: archilk@physics.usyd.edu.au [ARC Centre of Excellence for Particle Physics at the Terascale, School of Physics, The University of Sydney, NSW 2006 (Australia); Manning, Adrian, E-mail: a.manning@physics.usyd.edu.au [ARC Centre of Excellence for Particle Physics at the Terascale, School of Physics, The University of Sydney, NSW 2006 (Australia); Tureanu, Anca, E-mail: anca.tureanu@helsinki.fi [Department of Physics, University of Helsinki, P.O. Box 64, 00014 Helsinki (Finland)
2016-06-10
Zitterbewegung, as it was originally described by Schrödinger, is an unphysical, non-observable effect. We verify whether the effect can be observed in non-inertial reference frames/curved spacetimes, where the ambiguity in defining particle states results in a mixing of positive and negative frequency modes. We explicitly demonstrate that such a mixing is in fact necessary to obtain the correct classical value for a particle's velocity in a uniformly accelerated reference frame, whereas in cosmological spacetime a particle does indeed exhibit Zitterbewegung.
Differential geometry curves, surfaces, manifolds
Kohnel, Wolfgang
2002-01-01
This carefully written book is an introduction to the beautiful ideas and results of differential geometry. The first half covers the geometry of curves and surfaces, which provide much of the motivation and intuition for the general theory. Special topics that are explored include Frenet frames, ruled surfaces, minimal surfaces and the Gauss-Bonnet theorem. The second part is an introduction to the geometry of general manifolds, with particular emphasis on connections and curvature. The final two chapters are insightful examinations of the special cases of spaces of constant curvature and Einstein manifolds. The text is illustrated with many figures and examples. The prerequisites are undergraduate analysis and linear algebra.
LINS Curve in Romanian Economy
Directory of Open Access Journals (Sweden)
Emilian Dobrescu
2016-02-01
Full Text Available The paper presents theoretical considerations and empirical evidence to test the validity of the Laffer in Narrower Sense (LINS curve as a parabola with a maximum. Attention is focused on the so-called legal-effective tax gap (letg. The econometric application is based on statistical data (1990-2013 for Romania as an emerging European economy. Three cointegrating regressions (fully modified least squares, canonical cointegrating regression and dynamic least squares and three algorithms, which are based on instrumental variables (two-stage least squares, generalized method of moments, and limited information maximum likelihood, are involved.
Surface representations of two- and three-dimensional fluid flow topology
Helman, James L.; Hesselink, Lambertus
1990-01-01
We discuss our work using critical point analysis to generate representations of the vector field topology of numerical flow data sets. Critical points are located and characterized in a two-dimensional domain, which may be either a two-dimensional flow field or the tangential velocity field near a three-dimensional body. Tangent curves are then integrated out along the principal directions of certain classes of critical points. The points and curves are linked to form a skeleton representing the two-dimensional vector field topology. When generated from the tangential velocity field near a body in a three-dimensional flow, the skeleton includes the critical points and curves which provide a basis for analyzing the three-dimensional structure of the flow separation. The points along the separation curves in the skeleton are used to start tangent curve integrations to generate surfaces representing the topology of the associated flow separations.
Flow characteristics of curved ducts
Directory of Open Access Journals (Sweden)
Rudolf P.
2007-10-01
Full Text Available Curved channels are very often present in real hydraulic systems, e.g. curved diffusers of hydraulic turbines, S-shaped bulb turbines, fittings, etc. Curvature brings change of velocity profile, generation of vortices and production of hydraulic losses. Flow simulation using CFD techniques were performed to understand these phenomena. Cases ranging from single elbow to coupled elbows in shapes of U, S and spatial right angle position with circular cross-section were modeled for Re = 60000. Spatial development of the flow was studied and consequently it was deduced that minor losses are connected with the transformation of pressure energy into kinetic energy and vice versa. This transformation is a dissipative process and is reflected in the amount of the energy irreversibly lost. Least loss coefficient is connected with flow in U-shape elbows, biggest one with flow in Sshape elbows. Finally, the extent of the flow domain influenced by presence of curvature was examined. This isimportant for proper placement of mano- and flowmeters during experimental tests. Simulations were verified with experimental results presented in literature.
Improved capacitive melting curve measurements
International Nuclear Information System (INIS)
Sebedash, Alexander; Tuoriniemi, Juha; Pentti, Elias; Salmela, Anssi
2009-01-01
Sensitivity of the capacitive method for determining the melting pressure of helium can be enhanced by loading the empty side of the capacitor with helium at a pressure nearly equal to that desired to be measured and by using a relatively thin and flexible membrane in between. This way one can achieve a nanobar resolution at the level of 30 bar, which is two orders of magnitude better than that of the best gauges with vacuum reference. This extends the applicability of melting curve thermometry to lower temperatures and would allow detecting tiny anomalies in the melting pressure, which must be associated with any phenomena contributing to the entropy of the liquid or solid phases. We demonstrated this principle in measurements of the crystallization pressure of isotopic helium mixtures at millikelvin temperatures by using partly solid pure 4 He as the reference substance providing the best possible universal reference pressure. The achieved sensitivity was good enough for melting curve thermometry on mixtures down to 100 μK. Similar system can be used on pure isotopes by virtue of a blocked capillary giving a stable reference condition with liquid slightly below the melting pressure in the reference volume. This was tested with pure 4 He at temperatures 0.08-0.3 K. To avoid spurious heating effects, one must carefully choose and arrange any dielectric materials close to the active capacitor. We observed some 100 pW loading at moderate excitation voltages.
Classical optics and curved spaces
International Nuclear Information System (INIS)
Bailyn, M.; Ragusa, S.
1976-01-01
In the eikonal approximation of classical optics, the unit polarization 3-vector of light satisfies an equation that depends only on the index, n, of refraction. It is known that if the original 3-space line element is d sigma 2 , then this polarization direction propagates parallely in the fictitious space n 2 d sigma 2 . Since the equation depends only on n, it is possible to invent a fictitious curved 4-space in which the light performs a null geodesic, and the polarization 3-vector behaves as the 'shadow' of a parallely propagated 4-vector. The inverse, namely, the reduction of Maxwell's equation, on a curve 'dielectric free) space, to a classical space with dielectric constant n=(-g 00 ) -1 / 2 is well known, but in the latter the dielectric constant epsilon and permeability μ must also equal (-g 00 ) -1 / 2 . The rotation of polarization as light bends around the sun by utilizing the reduction to the classical space, is calculated. This (non-) rotation may then be interpreted as parallel transport in the 3-space n 2 d sigma 2 [pt
Secuencia genética y dinámica de excitaciones no lineales de ADN
Cuenda Cuenda, Sara
2007-01-01
La memoria se divide en tres partes: la que se refiere al modelo de sine-Gordon continuo; la segunda, relativa al modelo de sine-Gordon discreto; y la última, que trata el modelo de Peyrard-Bishop aplicado al ADN. La primera parte engloba los capítulos 2 y 3. El segundo capítulo es puramente introductorio, y trata del modelo de sine-Gordon homogéneo y continuo. En él se hace un repaso de la ecuación de sine-Gordon en coordenadas características en la geometría diferencial y ...
2002-01-01
The Atlas of Stress-Strain Curves, Second Edition is substantially bigger in page dimensions, number of pages, and total number of curves than the previous edition. It contains over 1,400 curves, almost three times as many as in the 1987 edition. The curves are normalized in appearance to aid making comparisons among materials. All diagrams include metric (SI) units, and many also include U.S. customary units. All curves are captioned in a consistent format with valuable information including (as available) standard designation, the primary source of the curve, mechanical properties (including hardening exponent and strength coefficient), condition of sample, strain rate, test temperature, and alloy composition. Curve types include monotonic and cyclic stress-strain, isochronous stress-strain, and tangent modulus. Curves are logically arranged and indexed for fast retrieval of information. The book also includes an introduction that provides background information on methods of stress-strain determination, on...
Transition curves for highway geometric design
Kobryń, Andrzej
2017-01-01
This book provides concise descriptions of the various solutions of transition curves, which can be used in geometric design of roads and highways. It presents mathematical methods and curvature functions for defining transition curves. .
Comparison and evaluation of mathematical lactation curve ...
African Journals Online (AJOL)
p2492989
A mathematical model of the lactation curve provides summary information about culling and milking strategies ..... Table 2 Statistics of the edited data for first lactation Holstein cows ..... Application of different models to the lactation curves of.
Form factors of descendant operators: reduction to perturbed M(2,2s+1) models
International Nuclear Information System (INIS)
Lashkevich, Michael; Pugai, Yaroslav
2015-01-01
In the framework of the algebraic approach to form factors in two-dimensional integrable models of quantum field theory we consider the reduction of the sine-Gordon model to the Φ 13 -perturbation of minimal conformal models of the M(2,2s+1) series. We find in an algebraic form the condition of compatibility of local operators with the reduction. We propose a construction that make it possible to obtain reduction compatible local operators in terms of screening currents. As an application we obtain exact multiparticle form factors for the compatible with the reduction conserved currents T ±2k , Θ ±(2k−2) , which correspond to the spin ±(2k−1) integrals of motion, for any positive integer k. Furthermore, we obtain all form factors of the operators T 2k T −2l , which generalize the famous TT̄ operator. The construction is analytic in the s parameter and, therefore, makes sense in the sine-Gordon theory.
Ait-Haddou, Rachid; Sakane, Yusuke; Nomura, Taishin
2013-01-01
We show that the generalized Bernstein bases in Müntz spaces defined by Hirschman and Widder (1949) and extended by Gelfond (1950) can be obtained as pointwise limits of the Chebyshev–Bernstein bases in Müntz spaces with respect to an interval [a,1][a,1] as the positive real number a converges to zero. Such a realization allows for concepts of curve design such as de Casteljau algorithm, blossom, dimension elevation to be transferred from the general theory of Chebyshev blossoms in Müntz spaces to these generalized Bernstein bases that we termed here as Gelfond–Bernstein bases. The advantage of working with Gelfond–Bernstein bases lies in the simplicity of the obtained concepts and algorithms as compared to their Chebyshev–Bernstein bases counterparts.
Bubble Collision in Curved Spacetime
International Nuclear Information System (INIS)
Hwang, Dong-il; Lee, Bum-Hoon; Lee, Wonwoo; Yeom, Dong-han
2014-01-01
We study vacuum bubble collisions in curved spacetime, in which vacuum bubbles were nucleated in the initial metastable vacuum state by quantum tunneling. The bubbles materialize randomly at different times and then start to grow. It is known that the percolation by true vacuum bubbles is not possible due to the exponential expansion of the space among the bubbles. In this paper, we consider two bubbles of the same size with a preferred axis and assume that two bubbles form very near each other to collide. The two bubbles have the same field value. When the bubbles collide, the collided region oscillates back-and-forth and then the collided region eventually decays and disappears. We discuss radiation and gravitational wave resulting from the collision of two bubbles
Bacterial streamers in curved microchannels
Rusconi, Roberto; Lecuyer, Sigolene; Guglielmini, Laura; Stone, Howard
2009-11-01
Biofilms, generally identified as microbial communities embedded in a self-produced matrix of extracellular polymeric substances, are involved in a wide variety of health-related problems ranging from implant-associated infections to disease transmissions and dental plaque. The usual picture of these bacterial films is that they grow and develop on surfaces. However, suspended biofilm structures, or streamers, have been found in natural environments (e.g., rivers, acid mines, hydrothermal hot springs) and are always suggested to stem from a turbulent flow. We report the formation of bacterial streamers in curved microfluidic channels. By using confocal laser microscopy we are able to directly image and characterize the spatial and temporal evolution of these filamentous structures. Such streamers, which always connect the inner corners of opposite sides of the channel, are always located in the middle plane. Numerical simulations of the flow provide evidences for an underlying hydrodynamic mechanism behind the formation of the streamers.
Ait-Haddou, Rachid
2013-02-01
We show that the generalized Bernstein bases in Müntz spaces defined by Hirschman and Widder (1949) and extended by Gelfond (1950) can be obtained as pointwise limits of the Chebyshev–Bernstein bases in Müntz spaces with respect to an interval [a,1][a,1] as the positive real number a converges to zero. Such a realization allows for concepts of curve design such as de Casteljau algorithm, blossom, dimension elevation to be transferred from the general theory of Chebyshev blossoms in Müntz spaces to these generalized Bernstein bases that we termed here as Gelfond–Bernstein bases. The advantage of working with Gelfond–Bernstein bases lies in the simplicity of the obtained concepts and algorithms as compared to their Chebyshev–Bernstein bases counterparts.
Quantum field theory in curved spacetime and black hole thermodynamics
Wald, Robert M
1994-01-01
In this book, Robert Wald provides a coherent, pedagogical introduction to the formulation of quantum field theory in curved spacetime. He begins with a treatment of the ordinary one-dimensional quantum harmonic oscillator, progresses through the construction of quantum field theory in flat spacetime to possible constructions of quantum field theory in curved spacetime, and, ultimately, to an algebraic formulation of the theory. In his presentation, Wald disentangles essential features of the theory from inessential ones (such as a particle interpretation) and clarifies relationships between various approaches to the formulation of the theory. He also provides a comprehensive, up-to-date account of the Unruh effect, the Hawking effect, and some of its ramifications. In particular, the subject of black hole thermodynamics, which remains an active area of research, is treated in depth. This book will be accessible to students and researchers who have had introductory courses in general relativity and quantum f...
Sibling curves of quadratic polynomials | Wiggins | Quaestiones ...
African Journals Online (AJOL)
Sibling curves were demonstrated in [1, 2] as a novel way to visualize the zeroes of real valued functions. In [3] it was shown that a polynomial of degree n has n sibling curves. This paper focuses on the algebraic and geometric properites of the sibling curves of real and complex quadratic polynomials. Key words: Quadratic ...
GLOBAL AND STRICT CURVE FITTING METHOD
Nakajima, Y.; Mori, S.
2004-01-01
To find a global and smooth curve fitting, cubic BSpline method and gathering line methods are investigated. When segmenting and recognizing a contour curve of character shape, some global method is required. If we want to connect contour curves around a singular point like crossing points,
Trigonometric Characterization of Some Plane Curves
Indian Academy of Sciences (India)
IAS Admin
(Figure 1). A relation between tan θ and tanψ gives the trigonometric equation of the family of curves. In this article, trigonometric equations of some known plane curves are deduced and it is shown that these equations reveal some geometric characteristics of the families of the curves under consideration. In Section 2,.
M-curves and symmetric products
Indian Academy of Sciences (India)
Indranil Biswas
2017-08-03
Aug 3, 2017 ... is bounded above by g + 1, where g is the genus of X [11]. Curves which have exactly the maximum number (i.e., genus +1) of components of the real part are called M-curves. Classifying real algebraic curves up to homeomorphism is straightforward, however, classifying even planar non-singular real ...
Holomorphic curves in exploded manifolds: Kuranishi structure
Parker, Brett
2013-01-01
This paper constructs a Kuranishi structure for the moduli stack of holomorphic curves in exploded manifolds. To avoid some technicalities of abstract Kuranishi structures, we embed our Kuranishi structure inside a moduli stack of curves. The construction also works for the moduli stack of holomorphic curves in any compact symplectic manifold.
Automated Blazar Light Curves Using Machine Learning
Energy Technology Data Exchange (ETDEWEB)
Johnson, Spencer James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2017-07-27
This presentation describes a problem and methodology pertaining to automated blazar light curves. Namely, optical variability patterns for blazars require the construction of light curves and in order to generate the light curves, data must be filtered before processing to ensure quality.
Energy Technology Data Exchange (ETDEWEB)
McGreevy, John Austen; /Stanford U., Phys. Dept.
2005-07-06
This thesis is a study of D-branes in string compactifications. In this context, D-branes are relevant as an important component of the nonperturbative spectrum, as an incisive probe of these backgrounds, and as a natural stringy tool for localizing gauge interactions. In the first part of the thesis, we discuss half-BPS D-branes in compactifications of type II string theory on Calabi-Yau threefolds. The results we describe for these objects are pertinent both in their role as stringy brane-worlds, and in their role as solitonic objects. In particular, we determine couplings of these branes to the moduli determining the closed-string geometry, both perturbatively and non-perturbatively in the worldsheet expansion. We provide a local model for transitions in moduli space where the BPS spectrum jumps, and discuss the extension of mirror symmetry between Calabi-Yau manifolds to the case when D-branes are present. The next section is an interlude which provides some applications of D-branes to other curved backgrounds of string theory. In particular, we discuss a surprising phenomenon in which fundamental strings moving through background Ramond-Ramond fields dissolve into large spherical D3-branes. This mechanism is used to explain a previously-mysterious fact discovered via the AdS-CFT correspondence. Next, we make a connection between type IIA string vacua of the type discussed in the first section and M-theory compactifications on manifolds of G{sub 2} holonomy. Finally we discuss constructions of string vacua which do not have large radius limits. In the final part of the thesis, we develop techniques for studying the worldsheets of open strings ending on the curved D-branes studied in the first section. More precisely, we formulate a large class of massive two-dimensional gauge theories coupled to boundary matter, which flow in the infrared to the relevant boundary conformal field theories. Along with many other applications, these techniques are used to describe
Method of construction spatial transition curve
Directory of Open Access Journals (Sweden)
S.V. Didanov
2013-04-01
Full Text Available Purpose. The movement of rail transport (speed rolling stock, traffic safety, etc. is largely dependent on the quality of the track. In this case, a special role is the transition curve, which ensures smooth insertion of the transition from linear to circular section of road. The article deals with modeling of spatial transition curve based on the parabolic distribution of the curvature and torsion. This is a continuation of research conducted by the authors regarding the spatial modeling of curved contours. Methodology. Construction of the spatial transition curve is numerical methods for solving nonlinear integral equations, where the initial data are taken coordinate the starting and ending points of the curve of the future, and the inclination of the tangent and the deviation of the curve from the tangent plane at these points. System solutions for the numerical method are the partial derivatives of the equations of the unknown parameters of the law of change of torsion and length of the transition curve. Findings. The parametric equations of the spatial transition curve are calculated by finding the unknown coefficients of the parabolic distribution of the curvature and torsion, as well as the spatial length of the transition curve. Originality. A method for constructing the spatial transition curve is devised, and based on this software geometric modeling spatial transition curves of railway track with specified deviations of the curve from the tangent plane. Practical value. The resulting curve can be applied in any sector of the economy, where it is necessary to ensure a smooth transition from linear to circular section of the curved space bypass. An example is the transition curve in the construction of the railway line, road, pipe, profile, flat section of the working blades of the turbine and compressor, the ship, plane, car, etc.
Induced gravity in quantum theory in a curved space
International Nuclear Information System (INIS)
Etim, E.
1983-01-01
The reason for interest in the unorthodox view of first order (about R(x)) gravity as a matter-induced quantum effect is really to find an argument not to quantise it. According to this view quantum gravity should be constructed with an action which is, at least, quadratic in the scalar curvature R(x). Such a theory will not contain a dimensional parameter, like Newton's constant, and would probably be renormalisable. This lecture is intended to acquaint the non-expert with the phenomenon of induction of the scalar curvature term in the matter Lagrangian in a curved space in both relativistic and non-relativistic quantum theories
Differential and symplectic topology of knots and curves
Tabachnikov, S
1999-01-01
This book presents a collection of papers on two related topics: topology of knots and knot-like objects (such as curves on surfaces) and topology of Legendrian knots and links in 3-dimensional contact manifolds. Featured is the work of international experts in knot theory (""quantum"" knot invariants, knot invariants of finite type), in symplectic and contact topology, and in singularity theory. The interplay of diverse methods from these fields makes this volume unique in the study of Legendrian knots and knot-like objects such as wave fronts. A particularly enticing feature of the volume is
Power forward curves: a managerial perspective
International Nuclear Information System (INIS)
Nagarajan, Shankar
1999-01-01
This chapter concentrates on managerial application of power forward curves, and examines the determinants of electricity prices such as transmission constraints, its inability to be stored in a conventional way, its seasonality and weather dependence, the generation stack, and the swing risk. The electricity forward curve, classical arbitrage, constructing a forward curve, volatilities, and electricity forward curve models such as the jump-diffusion model, the mean-reverting heteroscedastic volatility model, and an econometric model of forward prices are examined. A managerial perspective of the applications of the forward curve is presented covering plant valuation, capital budgeting, performance measurement, product pricing and structuring, asset optimisation, valuation of transmission options, and risk management
Retrograde curves of solidus and solubility
International Nuclear Information System (INIS)
Vasil'ev, M.V.
1979-01-01
The investigation was concerned with the constitutional diagrams of the eutectic type with ''retrograde solidus'' and ''retrograde solubility curve'' which must be considered as diagrams with degenerate monotectic transformation. The solidus and the solubility curves form a retrograde curve with a common retrograde point representing the solubility maximum. The two branches of the Aetrograde curve can be described with the aid of two similar equations. Presented are corresponding equations for the Cd-Zn system and shown is the possibility of predicting the run of the solubility curve
Global structure of curves from generalized unitarity cut of three-loop diagrams
International Nuclear Information System (INIS)
Hauenstein, Jonathan D.; Huang, Rijun; Mehta, Dhagash; Zhang, Yang
2015-01-01
This paper studies the global structure of algebraic curves defined by generalized unitarity cut of four-dimensional three-loop diagrams with eleven propagators. The global structure is a topological invariant that is characterized by the geometric genus of the algebraic curve. We use the Riemann-Hurwitz formula to compute the geometric genus of algebraic curves with the help of techniques involving convex hull polytopes and numerical algebraic geometry. Some interesting properties of genus for arbitrary loop orders are also explored where computing the genus serves as an initial step for integral or integrand reduction of three-loop amplitudes via an algebraic geometric approach.
The writhe of open and closed curves
International Nuclear Information System (INIS)
Berger, Mitchell A; Prior, Chris
2006-01-01
Twist and writhe measure basic geometric properties of a ribbon or tube. While these measures have applications in molecular biology, materials science, fluid mechanics and astrophysics, they are under-utilized because they are often considered difficult to compute. In addition, many applications involve curves with endpoints (open curves); but for these curves the definition of writhe can be ambiguous. This paper provides simple expressions for the writhe of closed curves, and provides a new definition of writhe for open curves. The open curve definition is especially appropriate when the curve is anchored at endpoints on a plane or stretches between two parallel planes. This definition can be especially useful for magnetic flux tubes in the solar atmosphere, and for isotropic rods with ends fixed to a plane
Page curves for tripartite systems
International Nuclear Information System (INIS)
Hwang, Junha; Lee, Deok Sang; Nho, Dongju; Oh, Jeonghun; Park, Hyosub; Zoe, Heeseung; Yeom, Dong-han
2017-01-01
We investigate information flow and Page curves for tripartite systems. We prepare a tripartite system (say, A , B , and C ) of a given number of states and calculate information and entropy contents by assuming random states. Initially, every particle was in A (this means a black hole), and as time goes on, particles move to either B (this means Hawking radiation) or C (this means a broadly defined remnant, including a non-local transport of information, the last burst, an interior large volume, or a bubble universe, etc). If the final number of states of the remnant is smaller than that of Hawking radiation, then information will be stored by both the radiation and the mutual information between the radiation and the remnant, while the remnant itself does not contain information. On the other hand, if the final number of states of the remnant is greater than that of Hawking radiation, then the radiation contains negligible information, while the remnant and the mutual information between the radiation and the remnant contain information. Unless the number of states of the remnant is large enough compared to the entropy of the black hole, Hawking radiation must contain information; and we meet the menace of black hole complementarity again. Therefore, this contrasts the tension between various assumptions and candidates of the resolution of the information loss problem. (paper)
Vacuum polarization in curved spacetime
International Nuclear Information System (INIS)
Guy, R.W.
1979-01-01
A necessary step in the process of understanding the quantum theory of gravity is the calculation of the stress-energy tensor of quantized fields in curved space-times. The determination of the stress tensor, a formally divergent object, is made possible in this dissertation by utilizing the zeta-function method of regularization and renormalization. By employing this scheme's representation of the renormalized effective action functional, an expression of the stress tensor for a massless, conformally invariant scalar field, first given by DeWitt, is derived. The form of the renormalized stress tensor is first tested in various examples of flat space-times. It is shown to vanish in Minkowski space and to yield the accepted value of the energy density in the Casimir effect. Next, the stress tensor is calculated in two space-times of constant curvature, the Einstein universe and the deSitter universe, and the results are shown to agree with those given by an expression of the stress tensor that is valid in conformally flat space-times. This work culminates in the determination of the stress tensor on the horizon of a Schwarzschild black hole. This is accomplished by approximating the radial part of the eigen-functions and the metric in the vicinity of the horizon. The stress tensor at this level approximation is found to be pure trace. The approximated forms of the Schwarzschild metric describes a conformally flat space-time that possesses horizons
An infinite-dimensional weak KAM theory via random variables
Gomes, Diogo A.; Nurbekyan, Levon
2016-01-01
We develop several aspects of the infinite-dimensional Weak KAM theory using a random variables' approach. We prove that the infinite-dimensional cell problem admits a viscosity solution that is a fixed point of the Lax-Oleinik semigroup. Furthermore, we show the existence of invariant minimizing measures and calibrated curves defined on R.
An infinite-dimensional weak KAM theory via random variables
Gomes, Diogo A.
2016-08-31
We develop several aspects of the infinite-dimensional Weak KAM theory using a random variables\\' approach. We prove that the infinite-dimensional cell problem admits a viscosity solution that is a fixed point of the Lax-Oleinik semigroup. Furthermore, we show the existence of invariant minimizing measures and calibrated curves defined on R.
Consistent Valuation across Curves Using Pricing Kernels
Directory of Open Access Journals (Sweden)
Andrea Macrina
2018-03-01
Full Text Available The general problem of asset pricing when the discount rate differs from the rate at which an asset’s cash flows accrue is considered. A pricing kernel framework is used to model an economy that is segmented into distinct markets, each identified by a yield curve having its own market, credit and liquidity risk characteristics. The proposed framework precludes arbitrage within each market, while the definition of a curve-conversion factor process links all markets in a consistent arbitrage-free manner. A pricing formula is then derived, referred to as the across-curve pricing formula, which enables consistent valuation and hedging of financial instruments across curves (and markets. As a natural application, a consistent multi-curve framework is formulated for emerging and developed inter-bank swap markets, which highlights an important dual feature of the curve-conversion factor process. Given this multi-curve framework, existing multi-curve approaches based on HJM and rational pricing kernel models are recovered, reviewed and generalised and single-curve models extended. In another application, inflation-linked, currency-based and fixed-income hybrid securities are shown to be consistently valued using the across-curve valuation method.
Construction of calibration curve for accountancy tank
International Nuclear Information System (INIS)
Kato, Takayuki; Goto, Yoshiki; Nidaira, Kazuo
2009-01-01
Tanks are equipped in a reprocessing plant for accounting solution of nuclear material. The careful measurement of volume in tanks is very important to implement rigorous accounting of nuclear material. The calibration curve relating the volume and level of solution needs to be constructed, where the level is determined by differential pressure of dip tubes. Several calibration curves are usually employed, but it's not explicitly decided how many segment are used, where to select segment, or what should be the degree of polynomial curve. These parameters, i.e., segment and degree of polynomial curve are mutually interrelated to give the better performance of calibration curve. Here we present the construction technique of giving optimum calibration curves and their characteristics. (author)
MICA: Multiple interval-based curve alignment
Mann, Martin; Kahle, Hans-Peter; Beck, Matthias; Bender, Bela Johannes; Spiecker, Heinrich; Backofen, Rolf
2018-01-01
MICA enables the automatic synchronization of discrete data curves. To this end, characteristic points of the curves' shapes are identified. These landmarks are used within a heuristic curve registration approach to align profile pairs by mapping similar characteristics onto each other. In combination with a progressive alignment scheme, this enables the computation of multiple curve alignments. Multiple curve alignments are needed to derive meaningful representative consensus data of measured time or data series. MICA was already successfully applied to generate representative profiles of tree growth data based on intra-annual wood density profiles or cell formation data. The MICA package provides a command-line and graphical user interface. The R interface enables the direct embedding of multiple curve alignment computation into larger analyses pipelines. Source code, binaries and documentation are freely available at https://github.com/BackofenLab/MICA
Inverse Diffusion Curves Using Shape Optimization.
Zhao, Shuang; Durand, Fredo; Zheng, Changxi
2018-07-01
The inverse diffusion curve problem focuses on automatic creation of diffusion curve images that resemble user provided color fields. This problem is challenging since the 1D curves have a nonlinear and global impact on resulting color fields via a partial differential equation (PDE). We introduce a new approach complementary to previous methods by optimizing curve geometry. In particular, we propose a novel iterative algorithm based on the theory of shape derivatives. The resulting diffusion curves are clean and well-shaped, and the final image closely approximates the input. Our method provides a user-controlled parameter to regularize curve complexity, and generalizes to handle input color fields represented in a variety of formats.
An Alternative to Wave Mechanics on Curved Spaces
Tomaschitz, R
1992-01-01
Geodesic motion in infinite spaces of constant negative curvature provides for the first time an example where a basically quantum mechanical quantity, a ground-state energy, is derived from Newtonian mechanics in a rigorous, non-semiclassical way. The ground state energy emerges as the Hausdorff dimension of a quasi-self-similar curve at infinity of three-dimensional hyperbolic space H in which our manifolds are embedded and where their universal covers are realized. This curve is just the locus of the limit set L(G) of the Kleinian group G of covering transformations, which determines the bounded trajectories in the manifold; all of them lie in the quotient C(L)/G, C(L) being the hyperbolic convex hull of L(G). The three-dimensional hyperbolic manifolds we construct can be visualized as thickened surfaces, topological products I x S, I a finite open interval, the fibers S compact Riemann surfaces. We give a short derivation of the Patterson formula connecting the ground-state energy with the Hausdorff dimen...
An alternative to wave mechanics on curved spaces
International Nuclear Information System (INIS)
Tomaschitz, R.
1992-01-01
Geodesic motion in infinite spaces of constant negative curvature provides for the first time an example where a basically quantum mechanical quantity, a ground-state energy, is derived from Newtonian mechanics in a rigorous, non-semiclassical way. The ground state energy emerges as the Hausdorff dimension of a quasi-self-similar curve at infinity of three-dimensional hyperbolic space H 3 in which our manifolds are embedded and where their universal covers are realized. This curve is just the locus of the limit set Λ(Γ) of the Kleinian group Γ of covering transformations, which determines the bounded trajectories in the manifold; all of them lie in the quotient C(Λ)/Γ, C(Γ) being the hyperbolic convex hull of Λ(Γ). The three-dimensional hyperbolic manifolds we construct can be visualized as thickened surfaces, topological products IxS, I a finite open interval, the fibers S compact Riemann surfaces. We give a short derivation of the Patterson formula connecting the ground-state energy with the Hausdorff dimension δ of Λ, and give various examples for the calculation of δ from the tessellations of the boundary of H 3 , induced by the universal coverings of the manifolds. 33 refs., 13 figs., 2 tabs
Drop shape visualization and contact angle measurement on curved surfaces.
Guilizzoni, Manfredo
2011-12-01
The shape and contact angles of drops on curved surfaces is experimentally investigated. Image processing, spline fitting and numerical integration are used to extract the drop contour in a number of cross-sections. The three-dimensional surfaces which describe the surface-air and drop-air interfaces can be visualized and a simple procedure to determine the equilibrium contact angle starting from measurements on curved surfaces is proposed. Contact angles on flat surfaces serve as a reference term and a procedure to measure them is proposed. Such procedure is not as accurate as the axisymmetric drop shape analysis algorithms, but it has the advantage of requiring only a side view of the drop-surface couple and no further information. It can therefore be used also for fluids with unknown surface tension and there is no need to measure the drop volume. Examples of application of the proposed techniques for distilled water drops on gemstones confirm that they can be useful for drop shape analysis and contact angle measurement on three-dimensional sculptured surfaces. Copyright © 2011 Elsevier Inc. All rights reserved.
Proposed Spontaneous Generation of Magnetic Fields by Curved Layers of a Chiral Superconductor
Kvorning, T.; Hansson, T. H.; Quelle, A.; Smith, C. Morais
2018-05-01
We demonstrate that two-dimensional chiral superconductors on curved surfaces spontaneously develop magnetic flux. This geometric Meissner effect provides an unequivocal signature of chiral superconductivity, which could be observed in layered materials under stress. We also employ the effect to explain some puzzling questions related to the location of zero-energy Majorana modes.
Regional Marginal Abatement Cost Curves for NOx
U.S. Environmental Protection Agency — Data underlying the figures included in the manuscript "Marginal abatement cost curve for NOx incorporating controls, renewable electricity, energy efficiency and...
Nonlinear dynamical modes of climate variability: from curves to manifolds
Gavrilov, Andrey; Mukhin, Dmitry; Loskutov, Evgeny; Feigin, Alexander
2016-04-01
The necessity of efficient dimensionality reduction methods capturing dynamical properties of the system from observed data is evident. Recent study shows that nonlinear dynamical mode (NDM) expansion is able to solve this problem and provide adequate phase variables in climate data analysis [1]. A single NDM is logical extension of linear spatio-temporal structure (like empirical orthogonal function pattern): it is constructed as nonlinear transformation of hidden scalar time series to the space of observed variables, i. e. projection of observed dataset onto a nonlinear curve. Both the hidden time series and the parameters of the curve are learned simultaneously using Bayesian approach. The only prior information about the hidden signal is the assumption of its smoothness. The optimal nonlinearity degree and smoothness are found using Bayesian evidence technique. In this work we do further extension and look for vector hidden signals instead of scalar with the same smoothness restriction. As a result we resolve multidimensional manifolds instead of sum of curves. The dimension of the hidden manifold is optimized using also Bayesian evidence. The efficiency of the extension is demonstrated on model examples. Results of application to climate data are demonstrated and discussed. The study is supported by Government of Russian Federation (agreement #14.Z50.31.0033 with the Institute of Applied Physics of RAS). 1. Mukhin, D., Gavrilov, A., Feigin, A., Loskutov, E., & Kurths, J. (2015). Principal nonlinear dynamical modes of climate variability. Scientific Reports, 5, 15510. http://doi.org/10.1038/srep15510
Particles and Dirac-type operators on curved spaces
International Nuclear Information System (INIS)
Visinescu, Mihai
2003-01-01
We review the geodesic motion of pseudo-classical particles in curved spaces. Investigating the generalized Killing equations for spinning spaces, we express the constants of motion in terms of Killing-Yano tensors. Passing from the spinning spaces to the Dirac equation in curved backgrounds we point out the role of the Killing-Yano tensors in the construction of the Dirac-type operators. The general results are applied to the case of the four-dimensional Euclidean Taub-Newman-Unti-Tamburino space. From the covariantly constant Killing-Yano tensors of this space we construct three new Dirac-type operators which are equivalent with the standard Dirac operator. Finally the Runge-Lenz operator for the Dirac equation in this background is expressed in terms of the fourth Killing-Yano tensor which is not covariantly constant. As a rule the covariantly constant Killing-Yano tensors realize certain square roots of the metric tensor. Such a Killing-Yano tensor produces simultaneously a Dirac-type operator and the generator of a one-parameter Lie group connecting this operator with the standard Dirac one. On the other hand, the not covariantly constant Killing-Yano tensors are important in generating hidden symmetries. The presence of not covariantly constant Killing-Yano tensors implies the existence of non-standard supersymmetries in point particle theories on curved background. (author)
Hong Shen
2011-01-01
The concepts of curve profile, curve intercept, curve intercept density, curve profile area density, intersection density in containing intersection (or intersection density relied on intersection reference), curve profile intersection density in surface (or curve intercept intersection density relied on intersection of containing curve), and curve profile area density in surface (AS) were defined. AS expressed the amount of curve profile area of Y phase in the unit containing surface area, S...
Polar representation of centrifugal pump homologous curves
International Nuclear Information System (INIS)
Veloso, Marcelo Antonio; Mattos, Joao Roberto Loureiro de
2008-01-01
Essential for any mathematical model designed to simulate flow transient events caused by pump operations is the pump performance data. The performance of a centrifugal pump is characterized by four basic parameters: the rotational speed, the volumetric flow rate, the dynamic head, and the hydraulic torque. Any one of these quantities can be expressed as a function of any two others. The curves showing the relationships between these four variables are called the pump characteristic curves, also referred to as four-quadrant curves. The characteristic curves are empirically developed by the pump manufacturer and uniquely describe head and torque as functions of volumetric flow rate and rotation speed. Because of comprising a large amount of points, the four-quadrant configuration is not suitable for computational purposes. However, it can be converted to a simpler form by the development of the homologous curves, in which dynamic head and hydraulic torque ratios are expressed as functions of volumetric flow and rotation speed ratios. The numerical use of the complete set of homologous curves requires specification of sixteen partial curves, being eight for the dynamic head and eight for the hydraulic torque. As a consequence, the handling of homologous curves is still somewhat complicated. In solving flow transient problems that require the pump characteristic data for all the operation zones, the polar form appears as the simplest way to represent the homologous curves. In the polar method, the complete characteristics of a pump can be described by only two closed curves, one for the dynamic head and other for the hydraulic torque, both in function of a single angular coordinate defined adequately in terms of the quotient between volumetric flow ratio and rotation speed ratio. The usefulness and advantages of this alternative method are demonstrated through a practical example in which the homologous curves for a pump of the type used in the main coolant loops of a
Migration and the Wage-Settings Curve
DEFF Research Database (Denmark)
Brücker, Herbert; Jahn, Elke
Germany on basis of a wage-setting curve. The wage-setting curve relies on the assumption that wages respond to a hange in the unemployment rate, albeit imperfectly. This allows one to derive the wage and employment effects of migration simultaneously in a general equilibrium framework. Using...
Learning curves in energy planning models
Energy Technology Data Exchange (ETDEWEB)
Barreto, L; Kypreos, S [Paul Scherrer Inst. (PSI), Villigen (Switzerland)
1999-08-01
This study describes the endogenous representation of investment cost learning curves into the MARKAL energy planning model. A piece-wise representation of the learning curves is implemented using Mixed Integer Programming. The approach is briefly described and some results are presented. (author) 3 figs., 5 refs.
The Koch curve as a smooth manifold
International Nuclear Information System (INIS)
Epstein, Marcelo; Sniatycki, Jedrzej
2008-01-01
We show that there exists a homeomorphism between the closed interval [0,1] is contained in R and the Koch curve endowed with the subset topology of R 2 . We use this homeomorphism to endow the Koch curve with the structure of a smooth manifold with boundary
International Nuclear Information System (INIS)
Bershadsky, M.; Radul, A.
1988-01-01
The line bundles of degree g-1 on Z N -curves corresponding to 1/N nonsingular characteristics are considered. The determinants of Dirac operators defined on these line bundles are evaluated in terms of branch points. The generalization of Thomae's formula for Z N -curves is derived. (orig.)
Measuring Model Rocket Engine Thrust Curves
Penn, Kim; Slaton, William V.
2010-01-01
This paper describes a method and setup to quickly and easily measure a model rocket engine's thrust curve using a computer data logger and force probe. Horst describes using Vernier's LabPro and force probe to measure the rocket engine's thrust curve; however, the method of attaching the rocket to the force probe is not discussed. We show how a…
A minicourse on moduli of curves
International Nuclear Information System (INIS)
Looijenga, E.
2000-01-01
These are notes that accompany a short course given at the School on Algebraic Geometry 1999 at the ICTP, Trieste. A major goal is to outline various approaches to moduli spaces of curves. In the last part I discuss the algebraic classes that naturally live on these spaces; these can be thought of as the characteristic classes for bundles of curves. (author)
Symmetry Properties of Potentiometric Titration Curves.
Macca, Carlo; Bombi, G. Giorgio
1983-01-01
Demonstrates how the symmetry properties of titration curves can be efficiently and rigorously treated by means of a simple method, assisted by the use of logarithmic diagrams. Discusses the symmetry properties of several typical titration curves, comparing the graphical approach and an explicit mathematical treatment. (Author/JM)
Deep-learnt classification of light curves
DEFF Research Database (Denmark)
Mahabal, Ashish; Gieseke, Fabian; Pai, Akshay Sadananda Uppinakudru
2017-01-01
Astronomy light curves are sparse, gappy, and heteroscedastic. As a result standard time series methods regularly used for financial and similar datasets are of little help and astronomers are usually left to their own instruments and techniques to classify light curves. A common approach is to d...
Hyper-and-elliptic-curve cryptography
Bernstein, D.J.; Lange, T.
2014-01-01
This paper introduces ‘hyper-and-elliptic-curve cryptography’, in which a single high-security group supports fast genus-2-hyperelliptic-curve formulas for variable-base-point single-scalar multiplication (for example, Diffie–Hellman shared-secret computation) and at the same time supports fast
Curve Matching with Applications in Medical Imaging
DEFF Research Database (Denmark)
Bauer, Martin; Bruveris, Martins; Harms, Philipp
2015-01-01
In the recent years, Riemannian shape analysis of curves and surfaces has found several applications in medical image analysis. In this paper we present a numerical discretization of second order Sobolev metrics on the space of regular curves in Euclidean space. This class of metrics has several...
Spinons, Solitons, and Breathers in Quasi-One-Dimensional Magnets
Broholm, Collin
2006-03-01
By scattering neutrons from coordination polymer magnets, we contrast the effects of a uniform and a staggered magnetic field on the quantum critical state of a spin-1/2 chain. In a partially magnetized state of copper pyrazine dinitrate (CuPzN) we find bounded spectral continua indicating that neutrons scatter from spin-1/2 quasi-particle pairs [1]. The complex boundaries including an incommensurate soft spot result from a field induced shift in the Fermi points for these quasi-particles. The measurements indicate that the magnetized state of CuPzN remains quantum critical. Copper benzoate [2] and CuCl2^.2(dimethylsulfoxide) (CDC) [3] differ from CuPzN in that there are two spins per unit cell along the spin chain. Rather than continuous spectra, we find resolution limited gapped excitations when these materials are subject to high fields. So with two spins per unit cell, an applied field can drive the spin-1/2 chain away from criticality. The explanation for this effect was provided by Affleck and Oshikawa. The alternating coordination environment induces a transverse staggered field and spinon binding. The quantum sine-Gordon model is the relevant low energy field theory and it predicts soliton and breather excitations at specific energies and wave vectors that we compare to the experiments. We shall also compare a complete measurement of the dynamic spin correlation function for CDC in a field to exact diagonalization results for a spin-1/2 chain with a staggered and uniform magnetic field [4]. [1] M. B. Stone, D. H. Reich, C. Broholm, K. Lefmann, C. Rischel, C. P. Landee, and M. M. Turnbull, Phys. Rev. Lett. 91, 037205 (2003). [2] M. Kenzelmann, Y. Chien, C. Broholm, D. H. Reich, and Y. Qiu, Phys. Rev. Lett. 93, 017204 (2004). [3] D. C. Dender, P. R. Hammar, Daniel H. Reich, C. Broholm, and G. Aeppli, Phys. Rev. Lett. 79, 1750 (1997). [4] M. Kenzelmann, C. D. Batista, Y. Chen, C. Broholm, D. H. Reich, S. Park, and Y. Qiu, Phys. Rev. B 71, 094411 (2005).
Remote sensing used for power curves
International Nuclear Information System (INIS)
Wagner, R; Joergensen, H E; Paulsen, U S; Larsen, T J; Antoniou, I; Thesbjerg, L
2008-01-01
Power curve measurement for large wind turbines requires taking into account more parameters than only the wind speed at hub height. Based on results from aerodynamic simulations, an equivalent wind speed taking the wind shear into account was defined and found to reduce the power standard deviation in the power curve significantly. Two LiDARs and a SoDAR are used to measure the wind profile in front of a wind turbine. These profiles are used to calculate the equivalent wind speed. The comparison of the power curves obtained with the three instruments to the traditional power curve, obtained using a cup anemometer measurement, confirms the results obtained from the simulations. Using LiDAR profiles reduces the error in power curve measurement, when these are used as relative instrument together with a cup anemometer. Results from the SoDAR do not show such promising results, probably because of noisy measurements resulting in distorted profiles
Parametric representation of centrifugal pump homologous curves
International Nuclear Information System (INIS)
Veloso, Marcelo A.; Mattos, Joao R.L. de
2015-01-01
Essential for any mathematical model designed to simulate flow transient events caused by pump operations is the pump performance data. The performance of a centrifugal pump is characterized by four basic quantities: the rotational speed, the volumetric flow rate, the dynamic head, and the hydraulic torque. The curves showing the relationships between these four variables are called the pump characteristic curves. The characteristic curves are empirically developed by the pump manufacturer and uniquely describe head and torque as functions of volumetric flow rate and rotation speed. Because of comprising a large amount of points, this configuration is not suitable for computational purposes. However, it can be converted to a simpler form by the development of the homologous curves, in which dynamic head and hydraulic torque ratios are expressed as functions of volumetric flow and rotation speed ratios. The numerical use of the complete set of homologous curves requires specification of sixteen partial curves, being eight for the dynamic head and eight for the hydraulic torque. As a consequence, the handling of homologous curves is still somewhat complicated. In solving flow transient problems that require the pump characteristic data for all the operation zones, the parametric form appears as the simplest way to deal with the homologous curves. In this approach, the complete characteristics of a pump can be described by only two closed curves, one for the dynamic head and other for the hydraulic torque, both in function of a single angular coordinate defined adequately in terms of the quotient between volumetric flow ratio and rotation speed ratio. The usefulness and advantages of this alternative method are demonstrated through a practical example in which the homologous curves for a pump of the type used in the main coolant loops of a pressurized water reactor (PWR) are transformed to the parametric form. (author)
Computerised curve deconvolution of TL/OSL curves using a popular spreadsheet program.
Afouxenidis, D; Polymeris, G S; Tsirliganis, N C; Kitis, G
2012-05-01
This paper exploits the possibility of using commercial software for thermoluminescence and optically stimulated luminescence curve deconvolution analysis. The widely used software package Microsoft Excel, with the Solver utility has been used to perform deconvolution analysis to both experimental and reference glow curves resulted from the GLOw Curve ANalysis INtercomparison project. The simple interface of this programme combined with the powerful Solver utility, allows the analysis of complex stimulated luminescence curves into their components and the evaluation of the associated luminescence parameters.
Computerised curve deconvolution of TL/OSL curves using a popular spreadsheet program
International Nuclear Information System (INIS)
Afouxenidis, D.; Polymeris, G. S.; Tsirliganis, N. C.; Kitis, G.
2012-01-01
This paper exploits the possibility of using commercial software for thermoluminescence and optically stimulated luminescence curve deconvolution analysis. The widely used software package Microsoft Excel, with the Solver utility has been used to perform deconvolution analysis to both experimental and reference glow curves resulted from the Glow Curve Analysis Intercomparison project. The simple interface of this programme combined with the powerful Solver utility, allows the analysis of complex stimulated luminescence curves into their components and the evaluation of the associated luminescence parameters. (authors)
Mannheim Partner D-Curves in the Euclidean 3-space
Directory of Open Access Journals (Sweden)
Mustafa Kazaz
2015-02-01
Full Text Available In this paper, we consider the idea of Mannheim partner curves for curves lying on surfaces. By considering the Darboux frames of surface curves, we define Mannheim partner D-curves and give the characterizations for these curves. We also find the relations between geodesic curvatures, normal curvatures and geodesic torsions of these associated curves. Furthermore, we show that definition and characterizations of Mannheim partner D-curves include those of Mannheim partner curves in some special cases.
The holographic RG flow in a field theory on a curved background
International Nuclear Information System (INIS)
Cardoso, Gabriel Lopes; Luest, Dieter
2002-01-01
As shown by Freedman, Gubser, Pilch and Warner, the RG flow in N=4 super-Yang-Mills theory broken to an N=1 theory by the addition of a mass term can be described in terms of a supersymmetric domain wall solution in five-dimensional N=8 gauged supergravity. The FGPW flow is an example of a holographic RG flow in a field theory on a flat background. Here we put the field theory studied by Freedman, Gubser, Pilch and Warner on a curved AdS 4 background, and we construct the supersymmetric domain wall solution which describes the RG flow in this field theory. This solution is a curved (non-Ricci flat) domain wall solution. This example demonstrates that holographic RG flows in supersymmetric field theories on a curved AdS 4 background can be described in terms of curved supersymmetric domain wall solutions. (author)
Time Alignment as a Necessary Step in the Analysis of Sleep Probabilistic Curves
Rošt'áková, Zuzana; Rosipal, Roman
2018-02-01
Sleep can be characterised as a dynamic process that has a finite set of sleep stages during the night. The standard Rechtschaffen and Kales sleep model produces discrete representation of sleep and does not take into account its dynamic structure. In contrast, the continuous sleep representation provided by the probabilistic sleep model accounts for the dynamics of the sleep process. However, analysis of the sleep probabilistic curves is problematic when time misalignment is present. In this study, we highlight the necessity of curve synchronisation before further analysis. Original and in time aligned sleep probabilistic curves were transformed into a finite dimensional vector space, and their ability to predict subjects' age or daily measures is evaluated. We conclude that curve alignment significantly improves the prediction of the daily measures, especially in the case of the S2-related sleep states or slow wave sleep.
A birational mapping with a strange attractor: post-critical set and covariant curves
International Nuclear Information System (INIS)
Bouamra, M; Hassani, S; Maillard, J-M
2009-01-01
We consider some two-dimensional birational transformations. One of them is a birational deformation of the Henon map. For some of these birational mappings, the post-critical set (i.e. the iterates of the critical set) is infinite and we show that this gives straightforwardly the algebraic covariant curves of the transformation when they exist. These covariant curves are used to build the preserved meromorphic 2-form. One may also have an infinite post-critical set yielding a covariant curve which is not algebraic (transcendental). For two of the birational mappings considered, the post-critical set is finite and we claim that there is no algebraic covariant curve and no preserved meromorphic 2-form. For these two mappings with finite post-critical sets, attracting sets occur and we show that they pass the usual tests (Lyapunov exponents and the fractal dimension) for being strange attractors. The strange attractor of one of these two mappings is unbounded.
A versatile curve-fit model for linear to deeply concave rank abundance curves
Neuteboom, J.H.; Struik, P.C.
2005-01-01
A new, flexible curve-fit model for linear to concave rank abundance curves was conceptualized and validated using observational data. The model links the geometric-series model and log-series model and can also fit deeply concave rank abundance curves. The model is based ¿ in an unconventional way
Three-dimensional tori and Arnold tongues
Energy Technology Data Exchange (ETDEWEB)
Sekikawa, Munehisa, E-mail: sekikawa@cc.utsunomiya-u.ac.jp [Department of Mechanical and Intelligent Engineering, Utsunomiya University, Utsunomiya-shi 321-8585 (Japan); Inaba, Naohiko [Organization for the Strategic Coordination of Research and Intellectual Property, Meiji University, Kawasaki-shi 214-8571 (Japan); Kamiyama, Kyohei [Department of Electronics and Bioinformatics, Meiji University, Kawasaki-shi 214-8571 (Japan); Aihara, Kazuyuki [Institute of Industrial Science, the University of Tokyo, Meguro-ku 153-8505 (Japan)
2014-03-15
This study analyzes an Arnold resonance web, which includes complicated quasi-periodic bifurcations, by conducting a Lyapunov analysis for a coupled delayed logistic map. The map can exhibit a two-dimensional invariant torus (IT), which corresponds to a three-dimensional torus in vector fields. Numerous one-dimensional invariant closed curves (ICCs), which correspond to two-dimensional tori in vector fields, exist in a very complicated but reasonable manner inside an IT-generating region. Periodic solutions emerge at the intersections of two different thin ICC-generating regions, which we call ICC-Arnold tongues, because all three independent-frequency components of the IT become rational at the intersections. Additionally, we observe a significant bifurcation structure where conventional Arnold tongues transit to ICC-Arnold tongues through a Neimark-Sacker bifurcation in the neighborhood of a quasi-periodic Hopf bifurcation (or a quasi-periodic Neimark-Sacker bifurcation) boundary.
Investigation of learning and experience curves
Energy Technology Data Exchange (ETDEWEB)
Krawiec, F.; Thornton, J.; Edesess, M.
1980-04-01
The applicability of learning and experience curves for predicting future costs of solar technologies is assessed, and the major test case is the production economics of heliostats. Alternative methods for estimating cost reductions in systems manufacture are discussed, and procedures for using learning and experience curves to predict costs are outlined. Because adequate production data often do not exist, production histories of analogous products/processes are analyzed and learning and aggregated cost curves for these surrogates estimated. If the surrogate learning curves apply, they can be used to estimate solar technology costs. The steps involved in generating these cost estimates are given. Second-generation glass-steel and inflated-bubble heliostat design concepts, developed by MDAC and GE, respectively, are described; a costing scenario for 25,000 units/yr is detailed; surrogates for cost analysis are chosen; learning and aggregate cost curves are estimated; and aggregate cost curves for the GE and MDAC designs are estimated. However, an approach that combines a neoclassical production function with a learning-by-doing hypothesis is needed to yield a cost relation compatible with the historical learning curve and the traditional cost function of economic theory.
Modelling curves of manufacturing feasibilities and demand
Directory of Open Access Journals (Sweden)
Soloninko K.S.
2017-03-01
Full Text Available The authors research the issue of functional properties of curves of manufacturing feasibilities and demand. Settlement of the problem, and its connection with important scientific and practical tasks. According to its nature, the market economy is unstable and is in constant movement. Economy has an effective instrument for explanation of changes in economic environment; this tool is called the modelling of economic processes. The modelling of economic processes depends first and foremost on the building of economic model which is the base for the formalization of economic process, that is, the building of mathematical model. The effective means for formalization of economic process is the creation of the model of hypothetic or imaginary economy. The building of demand model is significant for the market of goods and services. The problem includes the receiving (as the result of modelling definite functional properties of curves of manufacturing feasibilities and demand according to which one can determine their mathematical model. Another problem lies in obtaining majorant properties of curves of joint demand on the market of goods and services. Analysis of the latest researches and publications. Many domestic and foreign scientists dedicated their studies to the researches and building of the models of curves of manufacturing feasibilities and demand. In spite of considerable work of the scientists, such problems as functional properties of the curves and their practical use in modelling. The purpose of the article is to describe functional properties of curves of manufacturing feasibilities and demand on the market of goods and services on the base of modelling of their building. Scientific novelty and practical value. The theoretical regulations (for functional properties of curves of manufacturing feasibilities and demand received as a result of the present research, that is convexity, give extra practical possibilities in a microeconomic
Microfabrication on a curved surface using 3D microlens array projection
International Nuclear Information System (INIS)
Li, Lei; Yi, Allen Y
2009-01-01
Accurate three-dimensional microstructures on silicon or other substrates are becoming increasingly important for optical, electronic, biomedical and medical applications. Traditional microfabrication processes based on cleanroom lithography and dry or wet etching processes are essentially two-dimensional methods. In the past, complicated procedures were designed to create some three-dimensional microstructures; however, these processes were mainly used to create features on planar silicon wafer substrates using the bulk silicon machining technique. In a major departure from previous micromachining processes, a microfabrication process based on microlens projection is presented in this paper. The proposed microfabrication system will have the capabilities of a typical conventional micromachining process plus the unique true three-dimensional replication features based on microlenses that were created on a steep curved substrate. These microlenses were precisely fabricated with a specific pattern on the curved surface that can be used to create microstructures on a pre-defined nonplanar substrate where a layer of photoresist was spin coated. After proper exposure and development, the desired micro patterns are created on the photoresist layer. These micro features can eventually be replicated on the substrate via wet or dry etching processes. The results show that the fabricated three-dimensional microlens array has very high dimensional accuracy and the profile error is less than 6 µm over the entire surface
Reflected Light Curves of Extrasolar Planets
Green, D.; Matthews, J.; Kuschnig, R.; Seager, S.
The planned launches of ultra-precise photometric satellites such as MOST, COROT and MONS should provide the first opportunity to study the reflected light curves from extrasolar planets. To predict the capabilities of these missions, we have constructed a series of models of such light curves, improving upon the Monte Carlo simulations by Seager et al. (2000). These models include more realistic features such limb darkening of the star and broad band photometry. For specific models, the resulting planet light curves exhibit unique behavior with the variation of radius, inclination and presence or absence of clouds.
Neck curve polynomials in neck rupture model
International Nuclear Information System (INIS)
Kurniadi, Rizal; Perkasa, Yudha S.; Waris, Abdul
2012-01-01
The Neck Rupture Model is a model that explains the scission process which has smallest radius in liquid drop at certain position. Old fashion of rupture position is determined randomly so that has been called as Random Neck Rupture Model (RNRM). The neck curve polynomials have been employed in the Neck Rupture Model for calculation the fission yield of neutron induced fission reaction of 280 X 90 with changing of order of polynomials as well as temperature. The neck curve polynomials approximation shows the important effects in shaping of fission yield curve.
Morse theory on timelike and causal curves
International Nuclear Information System (INIS)
Everson, J.; Talbot, C.J.
1976-01-01
It is shown that the set of timelike curves in a globally hyperbolic space-time manifold can be given the structure of a Hilbert manifold under a suitable definition of 'timelike.' The causal curves are the topological closure of this manifold. The Lorentzian energy (corresponding to Milnor's energy, except that the Lorentzian inner product is used) is shown to be a Morse function for the space of causal curves. A fixed end point index theorem is obtained in which a lower bound for the index of the Hessian of the Lorentzian energy is given in terms of the sum of the orders of the conjugate points between the end points. (author)
Constructing forward price curves in electricity markets
DEFF Research Database (Denmark)
Fleten, S.-E.; Lemming, Jørgen Kjærgaard
2003-01-01
We present and analyze a method for constructing approximated high-resolution forward price curves in electricity markets. Because a limited number of forward or futures contracts are traded in the market, only a limited picture of the theoretical continuous forward price curve is available...... to the analyst. Our method combines the information contained in observed bid and ask prices with information from the forecasts generated by bottom-up models. As an example, we use information concerning the shape of the seasonal variation from a bottom-up model to improve the forward price curve quoted...
Curves of restricted type in euclidean spaces
Directory of Open Access Journals (Sweden)
Bengü Kılıç Bayram
2014-01-01
Full Text Available Submanifolds of restricted type were introduced in [7]. In the present study we consider restricted type of curves in Em. We give some special examples. We also show that spherical curve in S2(r C E3 is of restricted type if and only if either ƒ(s is constant or a linear function of s of the form ƒ(s = ±s + b and every closed W - curve of rank k and of length 2(r in E2k is of restricted type.
Constructing forward price curves in electricity markets
International Nuclear Information System (INIS)
Fleten, Stein-Erik; Lemming, Jacob
2003-01-01
We present and analyze a method for constructing approximated high-resolution forward price curves in electricity markets. Because a limited number of forward or futures contracts are traded in the market, only a limited picture of the theoretical continuous forward price curve is available to the analyst. Our method combines the information contained in observed bid and ask prices with information from the forecasts generated by bottom-up models. As an example, we use information concerning the shape of the seasonal variation from a bottom-up model to improve the forward price curve quoted on the Nordic power exchange
Growth curves for twins in Slovenia.
Bricelj, Katja; Blickstein, Isaac; Bržan-Šimenc, Gabrijela; Janša, Vid; Lučovnik, Miha; Verdenik, Ivan; Trojner-Bregar, Andreja; Tul, Nataša
2017-02-01
Abnormalities of fetal growth are more common in twins. We introduce the growth curves for monitoring fetal growth in twin pregnancies in Slovenia. Slovenian National Perinatal Information System for the period between 2002 and 2010 was used to calculate birth weight percentiles for all live born twins for each week from 22nd to 40th week. The calculated percentiles of birth weight for all live-born twins in Slovenia served as the basis for drawing 'growth' curves. The calculated growth curves for twins will help accurately diagnose small or large twin fetuses for their gestational age in the native central European population.
Wind Turbine Power Curves Incorporating Turbulence Intensity
DEFF Research Database (Denmark)
Sørensen, Emil Hedevang Lohse
2014-01-01
. The model and method are parsimonious in the sense that only a single function (the zero-turbulence power curve) and a single auxiliary parameter (the equivalent turbulence factor) are needed to predict the mean power at any desired turbulence intensity. The method requires only ten minute statistics......The performance of a wind turbine in terms of power production (the power curve) is important to the wind energy industry. The current IEC-61400-12-1 standard for power curve evaluation recognizes only the mean wind speed at hub height and the air density as relevant to the power production...
International Nuclear Information System (INIS)
Pan, Haoran; Koehler, Jonathan
2007-01-01
Learning curves have recently been widely adopted in climate-economy models to incorporate endogenous change of energy technologies, replacing the conventional assumption of an autonomous energy efficiency improvement. However, there has been little consideration of the credibility of the learning curve. The current trend that many important energy and climate change policy analyses rely on the learning curve means that it is of great importance to critically examine the basis for learning curves. Here, we analyse the use of learning curves in energy technology, usually implemented as a simple power function. We find that the learning curve cannot separate the effects of price and technological change, cannot reflect continuous and qualitative change of both conventional and emerging energy technologies, cannot help to determine the time paths of technological investment, and misses the central role of R and D activity in driving technological change. We argue that a logistic curve of improving performance modified to include R and D activity as a driving variable can better describe the cost reductions in energy technologies. Furthermore, we demonstrate that the top-down Leontief technology can incorporate the bottom-up technologies that improve along either the learning curve or the logistic curve, through changing input-output coefficients. An application to UK wind power illustrates that the logistic curve fits the observed data better and implies greater potential for cost reduction than the learning curve does. (author)
A simple Lissajous curves experimental setup
Şahin Kızılcık, Hasan; Damlı, Volkan
2018-05-01
The aim of this study is to develop an experimental setup to produce Lissajous curves. The setup was made using a smartphone, a powered speaker (computer speaker), a balloon, a laser pointer and a piece of mirror. Lissajous curves are formed as follows: a piece of mirror is attached to a balloon. The balloon is vibrated with the sound signal provided by the speaker that is connected to a smartphone. The laser beam is reflected off the mirror and the reflection is shaped as a Lissajous curve. Because of the intersection of two frequencies (frequency of the sound signal and natural vibration frequency of the balloon), these curves are formed. They can be used to measure the ratio of frequencies.
On ``minimally curved spacetimes'' in general relativity
Dadhich, Naresh
1997-01-01
We consider a spacetime corresponding to uniform relativistic potential analogus to Newtonian potential as an example of ``minimally curved spacetime''. We also consider a radially symmetric analogue of the Rindler spacetime of uniform proper acceleration relative to infinity.
Utilization of curve offsets in additive manufacturing
Haseltalab, Vahid; Yaman, Ulas; Dolen, Melik
2018-05-01
Curve offsets are utilized in different fields of engineering and science. Additive manufacturing, which lately becomes an explicit requirement in manufacturing industry, utilizes curve offsets widely. One of the necessities of offsetting is for scaling which is required if there is shrinkage after the fabrication or if the surface quality of the resulting part is unacceptable. Therefore, some post-processing is indispensable. But the major application of curve offsets in additive manufacturing processes is for generating head trajectories. In a point-wise AM process, a correct tool-path in each layer can reduce lots of costs and increase the surface quality of the fabricated parts. In this study, different curve offset generation algorithms are analyzed to show their capabilities and disadvantages through some test cases and improvements on their drawbacks are suggested.
Quaternion orders, quadratic forms, and Shimura curves
Alsina, Montserrat
2004-01-01
Shimura curves are a far-reaching generalization of the classical modular curves. They lie at the crossroads of many areas, including complex analysis, hyperbolic geometry, algebraic geometry, algebra, and arithmetic. The text provides an introduction to the subject from a theoretic and algorithmic perspective. The main topics covered in it are Shimura curves defined over the rational number field, the construction of their fundamental domains, and the determination of their complex multiplication points. The study of complex multiplication points in Shimura curves leads to the study of families of binary quadratic forms with algebraic coefficients and to their classification by arithmetic Fuchsian groups. In this regard, the authors develop a theory full of new possibilities which parallels Gauss' theory on the classification of binary quadratic forms with integral coefficients by the action of the modular group. Each topic covered in the book begins with a theoretical discussion followed by carefully worked...
Uncovering the skewness news impact curve
Czech Academy of Sciences Publication Activity Database
Anatolyev, Stanislav; Petukhov, A.
2016-01-01
Roč. 14, č. 4 (2016), s. 746-771 ISSN 1479-8409 Institutional support: RVO:67985998 Keywords : conditional skewness * news impact curve * stock returns Subject RIV: AH - Economics Impact factor: 1.800, year: 2016
Classification of ASKAP Vast Radio Light Curves
Rebbapragada, Umaa; Lo, Kitty; Wagstaff, Kiri L.; Reed, Colorado; Murphy, Tara; Thompson, David R.
2012-01-01
The VAST survey is a wide-field survey that observes with unprecedented instrument sensitivity (0.5 mJy or lower) and repeat cadence (a goal of 5 seconds) that will enable novel scientific discoveries related to known and unknown classes of radio transients and variables. Given the unprecedented observing characteristics of VAST, it is important to estimate source classification performance, and determine best practices prior to the launch of ASKAP's BETA in 2012. The goal of this study is to identify light curve characterization and classification algorithms that are best suited for archival VAST light curve classification. We perform our experiments on light curve simulations of eight source types and achieve best case performance of approximately 90% accuracy. We note that classification performance is most influenced by light curve characterization rather than classifier algorithm.
Automorphisms of double coverings of curves
International Nuclear Information System (INIS)
Torres, F.
1994-11-01
We study automorphisms of curves that commute with each other. We prove that the order and the number of fixed points of one of them satisfy certain relations involving those of the other. Then, we specialize our results to the case of double coverings of curves. For instance, if the genus of the curve is at least 4γ + 2 and γ >= 1 (γ = the genus of the covered curve) we prove that the order of an automorphism is bounded above by 2γ + 1 (resp. 4γ + 2) provided it is prime (resp. it has at least five fixed points). We also improve Farkas' bound on the number of fixed points namely 4γ + 4 by showing that it involves the order of the automorphism except in the case of even order when such an improvement is obtained provided the automorphism and the γ-involution has at least one common fixed point. (author). 15 refs
Uncovering the skewness news impact curve
Czech Academy of Sciences Publication Activity Database
Anatolyev, Stanislav; Petukhov, A.
2016-01-01
Roč. 14, č. 4 (2016), s. 746-771 ISSN 1479-8409 Institutional support: PRVOUK-P23 Keywords : conditional skewness * news impact curve * stock returns Subject RIV: AH - Economics Impact factor: 1.800, year: 2016
Transmission of wave energy in curved ducts
Rostafinski, W.
1973-01-01
A formation of wave energy flow was developed for motion in curved ducts. A parametric study over a range of frequencies determined the ability of circular bends to transmit energy for the case of perfectly rigid walls.
Twisted Vector Bundles on Pointed Nodal Curves
Indian Academy of Sciences (India)
Abstract. Motivated by the quest for a good compactification of the moduli space of -bundles on a nodal curve we establish a striking relationship between Abramovich's and Vistoli's twisted bundles and Gieseker vector bundles.
Statistics from dynamics in curved spacetime
International Nuclear Information System (INIS)
Parker, L.; Wang, Y.
1989-01-01
We consider quantum fields of spin 0, 1/2, 1, 3/2, and 2 with a nonzero mass in curved spacetime. We show that the dynamical Bogolubov transformations associated with gravitationally induced particle creation imply the connection between spin and statistics: By embedding two flat regions in a curved spacetime, we find that only when one imposes Bose-Einstein statistics for an integer-spin field and Fermi-Dirac statistics for a half-integer-spin field in the first flat region is the same type of statistics propagated from the first to the second flat region. This derivation of the flat-spacetime spin-statistics theorem makes use of curved-spacetime dynamics and does not reduce to any proof given in flat spacetime. We also show in the same manner that parastatistics, up to the fourth order, are consistent with the dynamical evolution of curved spacetime
RMS fatigue curves for random vibrations
International Nuclear Information System (INIS)
Brenneman, B.; Talley, J.G.
1984-01-01
Fatigue usage factors for deterministic or constant amplitude vibration stresses may be calculated with well known procedures and fatigue curves given in the ASME Boiler and Pressure Vessel Code. However, some phenomena produce nondeterministic cyclic stresses which can only be described and analyzed with statistical concepts and methods. Such stresses may be caused by turbulent fluid flow over a structure. Previous methods for solving this statistical fatigue problem are often difficult to use and may yield inaccurate results. Two such methods examined herein are Crandall's method and the ''3sigma'' method. The objective of this paper is to provide a method for creating ''RMS fatigue curves'' which accurately incorporate the requisite statistical information. These curves are given and may be used by analysts with the same ease and in the same manner as the ASME fatigue curves
Neutron cross sections: Book of curves
International Nuclear Information System (INIS)
McLane, V.; Dunford, C.L.; Rose, P.F.
1988-01-01
Neuton Cross Sections: Book of Curves represents the fourth edition of what was previously known as BNL-325, Neutron Cross Sections, Volume 2, CURVES. Data is presented only for (i.e., intergrated) reaction cross sections (and related fission parameters) as a function of incident-neutron energy for the energy range 0.01 eV to 200 MeV. For the first time, isometric state production cross sections have been included. 11 refs., 4 figs
Constructing elliptic curves from Galois representations
Snowden, Andrew; Tsimerman, Jacob
2017-01-01
Given a non-isotrivial elliptic curve over an arithmetic surface, one obtains a lisse $\\ell$-adic sheaf of rank two over the surface. This lisse sheaf has a number of straightforward properties: cyclotomic determinant, finite ramification, rational traces of Frobenius, and somewhere not potentially good reduction. We prove that any lisse sheaf of rank two possessing these properties comes from an elliptic curve.
Curved twistor spaces and H-space
International Nuclear Information System (INIS)
Tod, K.P.
1980-01-01
The curved twistor space construction of Penrose for anti-self-dual solutions to the Einstein vacuum equations is described. Curved twistor spaces are defined and it is shown with the aid of an example how to obtain them by deforming the complex structure of regions of flat twistor space. The connection of this procedure with Newman's H-space construction via asymptotic twistor space is outlined. (Auth.)
Potential Energy Curve of N2 Revisited
Czech Academy of Sciences Publication Activity Database
Špirko, Vladimír; Xiangzhu, L.; Paldus, J.
2011-01-01
Roč. 76, č. 4 (2011), s. 327-341 ISSN 0010-0765 R&D Projects: GA MŠk LC512; GA ČR GAP208/11/0436 Institutional research plan: CEZ:AV0Z40550506 Keywords : reduced multireference coupled-cluster method * reduced potential curve method * nitrogen molecule potential energy curves Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.283, year: 2011
Curvature Entropy for Curved Profile Generation
Ujiie, Yoshiki; Kato, Takeo; Sato, Koichiro; Matsuoka, Yoshiyuki
2012-01-01
In a curved surface design, the overall shape features that emerge from combinations of shape elements are important. However, controlling the features of the overall shape in curved profiles is difficult using conventional microscopic shape information such as dimension. Herein two types of macroscopic shape information, curvature entropy and quadrature curvature entropy, quantitatively represent the features of the overall shape. The curvature entropy is calculated by the curvature distribu...
Anomalies in curved spacetime at finite temperature
International Nuclear Information System (INIS)
Boschi-Filho, H.; Natividade, C.P.
1993-01-01
We discuss the problem of the breakdown of conformal and gauge symmetries at finite temperature in curved spacetime background, when the changes in the background are gradual. We obtain the expressions for the Seeley's coefficients and the heat kernel expansion in this regime. As applications, we consider the self-interacting lambda phi''4 and chiral Schwinger models in curved backgrounds at finite temperature. (Author) 9 refs
Learning curves in health professions education.
Pusic, Martin V; Boutis, Kathy; Hatala, Rose; Cook, David A
2015-08-01
Learning curves, which graphically show the relationship between learning effort and achievement, are common in published education research but are not often used in day-to-day educational activities. The purpose of this article is to describe the generation and analysis of learning curves and their applicability to health professions education. The authors argue that the time is right for a closer look at using learning curves-given their desirable properties-to inform both self-directed instruction by individuals and education management by instructors.A typical learning curve is made up of a measure of learning (y-axis), a measure of effort (x-axis), and a mathematical linking function. At the individual level, learning curves make manifest a single person's progress towards competence including his/her rate of learning, the inflection point where learning becomes more effortful, and the remaining distance to mastery attainment. At the group level, overlaid learning curves show the full variation of a group of learners' paths through a given learning domain. Specifically, they make overt the difference between time-based and competency-based approaches to instruction. Additionally, instructors can use learning curve information to more accurately target educational resources to those who most require them.The learning curve approach requires a fine-grained collection of data that will not be possible in all educational settings; however, the increased use of an assessment paradigm that explicitly includes effort and its link to individual achievement could result in increased learner engagement and more effective instructional design.
Environmental bias and elastic curves on surfaces
International Nuclear Information System (INIS)
Guven, Jemal; María Valencia, Dulce; Vázquez-Montejo, Pablo
2014-01-01
The behavior of an elastic curve bound to a surface will reflect the geometry of its environment. This may occur in an obvious way: the curve may deform freely along directions tangent to the surface, but not along the surface normal. However, even if the energy itself is symmetric in the curve's geodesic and normal curvatures, which control these modes, very distinct roles are played by the two. If the elastic curve binds preferentially on one side, or is itself assembled on the surface, not only would one expect the bending moduli associated with the two modes to differ, binding along specific directions, reflected in spontaneous values of these curvatures, may be favored. The shape equations describing the equilibrium states of a surface curve described by an elastic energy accommodating environmental factors will be identified by adapting the method of Lagrange multipliers to the Darboux frame associated with the curve. The forces transmitted to the surface along the surface normal will be determined. Features associated with a number of different energies, both of physical relevance and of mathematical interest, are described. The conservation laws associated with trajectories on surface geometries exhibiting continuous symmetries are also examined. (paper)
Geometric invariant theory for polarized curves
Bini, Gilberto; Melo, Margarida; Viviani, Filippo
2014-01-01
We investigate GIT quotients of polarized curves. More specifically, we study the GIT problem for the Hilbert and Chow schemes of curves of degree d and genus g in a projective space of dimension d-g, as d decreases with respect to g. We prove that the first three values of d at which the GIT quotients change are given by d=a(2g-2) where a=2, 3.5, 4. We show that, for a>4, L. Caporaso's results hold true for both Hilbert and Chow semistability. If 3.5curves. If 2curves. We also analyze in detail the critical values a=3.5 and a=4, where the Hilbert semistable locus is strictly smaller than the Chow semistable locus. As an application, we obtain three compactications of the universal Jacobian over the moduli space of stable curves, weakly-pseudo-stable curves and pseu...
Global experience curves for wind farms
International Nuclear Information System (INIS)
Junginger, M.; Faaij, A.; Turkenburg, W.C.
2005-01-01
In order to forecast the technological development and cost of wind turbines and the production costs of wind electricity, frequent use is made of the so-called experience curve concept. Experience curves of wind turbines are generally based on data describing the development of national markets, which cause a number of problems when applied for global assessments. To analyze global wind energy price development more adequately, we compose a global experience curve. First, underlying factors for past and potential future price reductions of wind turbines are analyzed. Also possible implications and pitfalls when applying the experience curve methodology are assessed. Second, we present and discuss a new approach of establishing a global experience curve and thus a global progress ratio for the investment cost of wind farms. Results show that global progress ratios for wind farms may lie between 77% and 85% (with an average of 81%), which is significantly more optimistic than progress ratios applied in most current scenario studies and integrated assessment models. While the findings are based on a limited amount of data, they may indicate faster price reduction opportunities than so far assumed. With this global experience curve we aim to improve the reliability of describing the speed with which global costs of wind power may decline
Holographic RG flows on curved manifolds and quantum phase transitions
Ghosh, J. K.; Kiritsis, E.; Nitti, F.; Witkowski, L. T.
2018-05-01
Holographic RG flows dual to QFTs on maximally symmetric curved manifolds (dS d , AdS d , and S d ) are considered in the framework of Einstein-dilaton gravity in d + 1 dimensions. A general dilaton potential is used and the flows are driven by a scalar relevant operator. The general properties of such flows are analyzed and the UV and IR asymptotics computed. New RG flows can appear at finite curvature which do not have a zero curvature counterpart. The so-called `bouncing' flows, where the β-function has a branch cut at which it changes sign, are found to persist at finite curvature. Novel quantum first-order phase transitions are found, triggered by a variation in the d-dimensional curvature in theories allowing multiple ground states.
Point splitting in a curved space-time background
International Nuclear Information System (INIS)
Liggatt, P.A.J.; Macfarlane, A.J.
1979-01-01
A prescription is given for point splitting in a curved space-time background which is a natural generalization of that familiar in quantum electrodynamics and Yang-Mills theory. It is applied (to establish its validity) to the verification of the gravitational anomaly in the divergence of a fermion axial current. Notable features of the prescription are that it defines a point-split current that can be differentiated straightforwardly, and that it involves a natural way of averaging (four-dimensionally) over the directions of point splitting. The method can extend directly from the spin-1/2 fermion case treated to other cases, e.g., to spin-3/2 Rarita-Schwinger fermions. (author)
Semiclassical methods in curved spacetime and black hole thermodynamics
International Nuclear Information System (INIS)
Camblong, Horacio E.; Ordonez, Carlos R.
2005-01-01
Improved semiclassical techniques are developed and applied to a treatment of a real scalar field in a D-dimensional gravitational background. This analysis, leading to a derivation of the thermodynamics of black holes, is based on the simultaneous use of (i) a near-horizon description of the scalar field in terms of conformal quantum mechanics; (ii) a novel generalized WKB framework; and (iii) curved-spacetime phase-space methods. In addition, this improved semiclassical approach is shown to be asymptotically exact in the presence of hierarchical expansions of a near-horizon type. Most importantly, this analysis further supports the claim that the thermodynamics of black holes is induced by their near-horizon conformal invariance