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  • Articles  (7,654)
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  • American Institute of Physics (AIP)  (7,654)
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  • 1
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    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 43 (2002), S. 3892-3915 
    ISSN: 1089-7658
    Source: AIP Digital Archive
    Topics: Mathematics , Physics
    Notes: We investigate the discrete spectrum of the Hamiltonian describing a quantum particle living in the two-dimensional straight strip. We impose the combined Dirichlet and Neumann boundary conditions on different parts of the boundary. Several statements on the existence or the absence of the discrete spectrum are compared for two models with combined boundary conditions. Examples of eigenfunctions and eigenvalues are computed numerically. © 2002 American Institute of Physics.
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  • 2
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    Journal of Mathematical Physics 43 (2002), S. 3879-3891 
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    Topics: Mathematics , Physics
    Notes: The present article is concerned with minimizers of the attractive Hartree energy functional Hg[ψ¯,ψ]=〈fraction SHAPE="CASE"〉12||∇ψ||22+(ψ,vψ)2+g(ψ,V * |ψ|2ψ)2 on Rd, d≥2, for a general class of external potentials v and two-body interactions V of positive type, with g〈0. We prove spontaneous symmetry breaking in the large coupling limit. A numerical investigation visualizes this regime in the example of an external double well potential. © 2002 American Institute of Physics.
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  • 3
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    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 43 (2002), S. 3927-3936 
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    Topics: Mathematics , Physics
    Notes: We show that the spectral theory of the Dirac operator D=i∂(Slashthrough accent mark)−σ(x)−iπ(x)γ5, in a static background (σ(x),π(x)) in 1+1 space–time dimensions, is underlined by a certain novel generalization of supersymmetric quantum mechanics, and we explore some of its mathematical and physical consequences. © 2002 American Institute of Physics.
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  • 4
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    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 43 (2002), S. 3916-3926 
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    Topics: Mathematics , Physics
    Notes: We present a new method for finding isolated exact solutions of a class of nonadiabatic Hamiltonians of relevance to quantum optics and allied areas. Central to our approach is the use of Bogoliubov transformations of the bosonic fields in the models. We demonstrate the simplicity and efficiency of this method by applying it to the Rabi Hamiltonian. © 2002 American Institute of Physics.
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  • 5
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    Journal of Mathematical Physics 43 (2002), S. 3952-3962 
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    Topics: Mathematics , Physics
    Notes: We aimed to obtain the energy levels of massive spin-1 particles moving in a constant magnetic field. The method used here is completely algebraic. In the process to obtain the energy levels the wave function is expressed in terms of Laguerre polynomials. © 2002 American Institute of Physics.
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  • 6
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    Journal of Mathematical Physics 43 (2002), S. 3944-3951 
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    Topics: Mathematics , Physics
    Notes: We show that a diagonalizable (non-Hermitian) Hamiltonian H is pseudo-Hermitian if and only if it has an antilinear symmetry, i.e., a symmetry generated by an invertible antilinear operator. This implies that the eigenvalues of H are real or come in complex conjugate pairs if and only if H possesses such a symmetry. In particular, the reality of the spectrum of H implies the presence of an antilinear symmetry. We further show that the spectrum of H is real if and only if there is a positive-definite inner-product on the Hilbert space with respect to which H is Hermitian or alternatively there is a pseudo-canonical transformation of the Hilbert space that maps H into a Hermitian operator. © 2002 American Institute of Physics.
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  • 7
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    Journal of Mathematical Physics 43 (2002), S. 3937-3943 
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    Topics: Mathematics , Physics
    Notes: It is shown that the renormalizability of the zero-range interaction in the two-dimensional space is always followed by the existence of a bound state, which is not true for odd-dimensional spaces. A renormalization procedure is defined and the exact retarded Green's function for electrons moving in two dimensions and interacting with both crossed magnetic and electric fields and an attractive zero-range interaction is constructed. Imaginary parts of poles of this Green's function determine lifetimes of quasibound (resonance) states. It is shown that for some particular parameters the stabilization against decay occurs even for strong electric fields. © 2002 American Institute of Physics.
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  • 8
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    Journal of Mathematical Physics 43 (2002), S. 3963-3983 
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    Topics: Mathematics , Physics
    Notes: The propagator for the radial Dirac equation is explicitly constructed. It turns out to be a distribution of order zero, but it is shown that there exists no path-space measure associated with this equation. © 2002 American Institute of Physics.
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  • 9
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    Journal of Mathematical Physics 43 (2002), S. 4035-4040 
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    Notes: We show that the reduced Dubrovin–Novikov hydrodynamic type models are integrable Nambu mechanical systems admitting Lax triples. © 2002 American Institute of Physics.
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  • 10
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    Journal of Mathematical Physics 43 (2002), S. 4020-4034 
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    Topics: Mathematics , Physics
    Notes: We study the set CZ of invariants [Zakhary and Carminati, J. Math. Phys. 42, 1474 (2001)] for the class of space–times whose Ricci tensors possess a null eigenvector. We show that all cases are maximally backsolvable, in terms of sets of invariants from CZ, but that some cases are not completely backsolvable and these all possess an alignment between an eigenvector of the Ricci tensor with a repeated principal null vector of the Weyl tensor. We provide algebraically complete sets for each canonically different space–time and hence conclude with these results and those of a previous article [Carminati, Zakhary, and McLenaghan, J. Math. Phys. 43, 492 (2002)] that the CZ set is determining or maximal. © 2002 American Institute of Physics.
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  • 11
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    Journal of Mathematical Physics 43 (2002), S. 4041-4059 
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    Topics: Mathematics , Physics
    Notes: Two-dimensional Hamiltonian systems admitting second invariants which are quartic in the momenta are investigated using the Jacobi geometrization of the dynamics. This approach allows for a unified treatment of invariants at both arbitrary and fixed energy. In the differential geometric picture, the quartic invariant corresponds to the existence of a fourth rank Killing tensor. Expressing the Jacobi metric in terms of a Kähler potential, the integrability condition for the existence of the Killing tensor at fixed energy is a nonlinear equation involving the Kähler potential. At arbitrary energy, further conditions must be imposed which lead to an overdetermined system with isolated solutions. We obtain several new integrable and superintegrable systems in addition to all previously known examples. © 2002 American Institute of Physics.
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  • 12
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    Journal of Mathematical Physics 43 (2002), S. 4060-4077 
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    Topics: Mathematics , Physics
    Notes: The multisymplectic structure of the KP equation is obtained directly from the variational principal. Using the covariant De Donder–Weyl Hamilton function theories, we reformulate the KP equation to the multisymplectic form which was proposed by Bridges. From the multisymplectic equation, we can derive a multisymplectic numerical scheme of the KP equation which can be simplified to the multisymplectic 45 points scheme. © 2002 American Institute of Physics.
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  • 13
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    Journal of Mathematical Physics 43 (2002), S. 3984-4019 
    ISSN: 1089-7658
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    Topics: Mathematics , Physics
    Notes: We continue a previous analysis of the covariant Hamiltonian symplectic structure of general relativity for spatially bounded regions of space–time. To allow for wide generality, the Hamiltonian is formulated using any fixed hypersurface, with a boundary given by a closed spacelike two-surface. A main result is that we obtain Hamiltonians associated with Dirichlet and Neumann boundary conditions on the gravitational field coupled to matter sources, in particular a Klein–Gordon field, an electromagnetic field, and a set of Yang–Mills–Higgs fields. The Hamiltonians are given by a covariant form of the Arnowitt–Deser–Misner (ADM) Hamiltonian modified by a surface integral term that depends on the particular boundary conditions. The general form of this surface integral involves an underlying "energy-momentum" vector in the space–time tangent space at the spatial boundary two-surface. We give examples of the resulting Dirichlet and Neumann vectors for topologically spherical two-surfaces in Minkowski space–time, spherically symmetric space–times, and stationary axisymmetric space–times. Moreover, we establish the relation between these vectors and the ADM energy-momentum vector for a two-surface taken in a limit to be spatial infinity in asymptotically flat space–times. We also discuss the geometrical properties of the Dirichlet and Neumann vectors and obtain several striking results relating these vectors to the mean curvature and normal curvature connection of the two-surface. Most significantly, the part of the Dirichlet vector normal to the two-surface depends only on the space–time metric at this surface and thereby defines a geometrical normal vector field on the two-surface. We show that this normal vector is orthogonal to the mean curvature vector, and its norm is the mean null extrinsic curvature, while its direction is such that there is zero expansion of the two-surface, i.e., the Lie derivative of the surface volume form in this direction vanishes. This leads to a direct relation between the Dirichlet vector and the condition for a spacelike two-surface to be (marginally) trapped. © 2002 American Institute of Physics.
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  • 14
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    Journal of Mathematical Physics 43 (2002), S. 4078-4109 
    ISSN: 1089-7658
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    Topics: Mathematics , Physics
    Notes: The (2+1)-dimensional (M+N)-component AKNS system that is derived from the inner parameter dependent symmetry constraint of the KP equation is studied in detail. First, the Painlevé integrability of the model is proved by using the standard WTC and Kruskal approach. Using the formal series symmetry approach, the generalized KMV symmetry algebra and the related symmetry group are found. The two-dimensional similarity partial differential equation reductions and the ordinary differential equation reductions are obtained from the generalized KMV symmetry algebra and the direct method. Abundant localized coherent structures are revealed by the variable separation approach. Some special types of the localized excitations like the multiple solitoffs, dromions, lumps, ring solitons, breathers and instantons are plotted also. © 2002 American Institute of Physics.
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  • 15
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    Journal of Mathematical Physics 43 (2002), S. 4127-4134 
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    Notes: A low energy bound for static classical solutions in a class of chiral solitonic field theories related to the infrared physics of the SU(N) Yang–Mills theory is established. © 2002 American Institute of Physics.
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  • 16
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    Journal of Mathematical Physics 43 (2002), S. 4147-4157 
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    Topics: Mathematics , Physics
    Notes: An index evaluating the amount of chirality of a mixture of colored random variables is defined. Properties are established. Extreme chiral mixtures are characterized and examples are given. Connections between chirality, Wasserstein distances, and least squares Procrustes methods are pointed out. © 2002 American Institute of Physics.
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  • 17
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    Journal of Mathematical Physics 43 (2002), S. 4110-4126 
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    Notes: The symmetry properties of a classical N-dimensional harmonic oscillator with rational frequency ratios are studied from a global point of view. A commensurate oscillator possesses the same number of globally defined constants of motion as an isotropic oscillator. In both cases invariant phase-space functions form the algebra su(N) with respect to the Poisson bracket. In the isotropic case, the phase-space flows generated by the invariants can be integrated globally to a set of finite transformations isomorphic to the group SU(N). For a commensurate oscillator, however, the group SU(N) of symmetry transformations is found to exist only on a reduced phase space, due to unavoidable singularities of the flow in the full phase space. It is therefore crucial to distinguish carefully between local and global definitions of symmetry transformations in phase space. This result solves the longstanding problem of which symmetry to associate with a commensurate harmonic oscillator. © 2002 American Institute of Physics.
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  • 18
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    Journal of Mathematical Physics 43 (2002), S. 4135-4146 
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    Notes: A number of conjectures have been given recently concerning the connection between the antiferromagnetic XXZ spin chain at Δ=−1/2 and various symmetry classes of alternating sign matrices. Here we use the integrability of the XXZ chain to gain further insight into these developments. In doing so we obtain a number of new results using Baxter's Q function for the XXZ chain for periodic, twisted and open boundary conditions. These include expressions for the elementary symmetric functions evaluated at the ground state solution of the Bethe roots. In this approach Schur functions play a central role and enable us to derive determinant expressions which appear in certain natural double products over the Bethe roots. When evaluated these give rise to the numbers counting different symmetry classes of alternating sign matrices. © 2002 American Institute of Physics.
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  • 19
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    Journal of Mathematical Physics 43 (2002), S. 4158-4179 
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    Topics: Mathematics , Physics
    Notes: We give a complete proof of the twisted duality property M(q)′=Z˜M(q⊥)Z˜* of the (self-dual) CAR-Algebra in any Fock representation. The proof is based on the natural Halmos decomposition of the (reference) Hilbert space when two suitable closed subspaces have been distinguished. We use modular theory and techniques developed by Kato concerning pairs of projections in some essential steps of the proof. As a byproduct of the proof we obtain an explicit and simple formula for the graph of the modular operator. This formula can be also applied to fermionic free nets, hence giving a formula of the modular operator for any double cone. © 2002 American Institute of Physics.
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  • 20
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    Journal of Mathematical Physics 43 (2002), S. 4180-4201 
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    Notes: A new way of constructing fusion bases (i.e., the set of inequalities governing fusion rules) out of fusion elementary couplings is presented. It relies on a polytope reinterpretation of the problem: the elementary couplings are associated with the vertices of the polytope while the inequalities defining the fusion basis are the facets. The symmetry group of the polytope associated with the lowest rank affine Lie algebras is found; it has order 24 for su&dbgcaret;(2), 432 for su&dbgcaret;(3) and quite surprisingly, it reduces to 36 for su&dbgcaret;(4), while it is only of order 4 for sp&dbgcaret;(4). This drastic reduction in the order of the symmetry group as the algebra gets more complicated is rooted in the presence of many linear relations between the elementary couplings that break most of the potential symmetries. For su&dbgcaret;(2) and su&dbgcaret;(3), it is shown that the fusion-basis defining inequalities can be generated from few (one and two, respectively) elementary ones. For su&dbgcaret;(3), new symmetries of the fusion coefficients are found. © 2002 American Institute of Physics.
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  • 21
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    Journal of Mathematical Physics 43 (2002), S. 4221-4233 
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    Notes: The problem of construction of irreducible representations of quantum Anq algebras is solved by explicit integration of the linear (inhomogeneous) system of equations in finite differences in the n-dimensional space. The general solution of this system is given explicitly, and particular solutions corresponding to the irreducible representations are selected. © 2002 American Institute of Physics.
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  • 22
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    Journal of Mathematical Physics 43 (2002), S. 4202-4220 
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    Topics: Mathematics , Physics
    Notes: The introduction of a lattice converts a singular boundary-layer problem in the continuum into a regular perturbation problem. However, the continuum limit of the discrete problem is extremely nontrivial and is not completely understood. This article examines two singular boundary-layer problems taken from mathematical physics, the instanton problem and the Blasius equation, and in each case examines two strategies, Padé resummation and variational perturbation theory, to recover the solution to the continuum problem from the solution to the associated discrete problem. Both resummation procedures produce good and interesting results for the two cases, but the results still deviate from the exact solutions. To understand the discrepancy a comprehensive large-order behavior analysis of the strong-coupling lattice expansions for each of the two problems is done. © 2002 American Institute of Physics.
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  • 23
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    Journal of Mathematical Physics 43 (2002), S. 2051-2062 
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    Notes: The controllability property of the unitary propagator of an N-level quantum mechanical system subject to a single control field is described using the structure theory of semisimple Lie algebras. Sufficient conditions are provided for the vector fields in a generic configuration as well as in a few degenerate cases. © 2002 American Institute of Physics.
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  • 24
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    Journal of Mathematical Physics 43 (2002), S. 2063-2096 
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    Notes: States which minimize the Schrödinger–Robertson uncertainty relation are constructed as eigenstates of an operator which is an element of the h(1)⊕su(2) algebra. The relations with supercoherent and supersqueezed states of the supersymmetric harmonic oscillator are given. Moreover, we are able to compute general Hamiltonians which behave like the harmonic oscillator Hamiltonian or are related to the Jaynes–Cummings Hamiltonian. © 2002 American Institute of Physics.
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  • 25
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    Journal of Mathematical Physics 43 (2002), S. 2097-2106 
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    Notes: We consider the problem of reversing quantum dynamics, with the goal of preserving an initial state's quantum entanglement or classical correlation with a reference system. We exhibit an approximate reversal operation, adapted to the initial density operator and the "noise" dynamics to be reversed. We show that its error in preserving either quantum or classical information is no more than twice that of the optimal reversal operation. Applications to quantum algorithms and information transmission are discussed. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2133-2150 
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    Notes: As an extension of the intertwining operator idea, an algebraic method which provides a link between supersymmetric quantum mechanics and quantum (super)integrability is introduced. By realization of the method in two dimensions, two infinite families of superintegrable and isospectral stationary potentials are generated. The method makes it possible to perform Darboux transformations in such a way that, in addition to the isospectral property, they acquire the superintegrability preserving property. Symmetry generators are second and fourth order in derivatives and all potentials are isospectral with one of the Smorodinsky–Winternitz potentials. Explicit expressions of the potentials, their dynamical symmetry generators, and the algebra they obey as well as their degenerate spectra and corresponding normalizable states are presented. © 2002 American Institute of Physics.
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  • 27
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    Journal of Mathematical Physics 43 (2002), S. 2107-2132 
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    Notes: We apply the techniques of control theory and of sub-Riemannian geometry to laser-induced population transfer in two- and three-level quantum systems. The aim is to induce complete population transfer by one or two laser pulses minimizing the pulse fluences. Sub-Riemannian geometry and singular-Riemannian geometry provide a natural framework for this minimization, where the optimal control is expressed in terms of geodesics. We first show that in two-level systems the well-known technique of "π-pulse transfer" in the rotating wave approximation emerges naturally from this minimization. In three-level systems driven by two resonant fields, we also find the counterpart of the "π-pulse transfer." This geometrical picture also allows one to analyze the population transfer by adiabatic passage. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2151-2168 
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    Notes: The most general admissible boundary conditions are derived for an idealized Aharonov–Bohm flux intersecting the plane at the origin on the background of a homogeneous magnetic field. A standard technique based on self-adjoint extensions yields a four-parameter family of boundary conditions; the other two parameters of the model are the Aharonov–Bohm flux and the homogeneous magnetic field. The generalized boundary conditions may be regarded as a combination of the Aharonov–Bohm effect with a point interaction. Spectral properties of the derived Hamtonians are studied in detail. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2169-2179 
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    Notes: A numerically exact phase-amplitude method that has been presented earlier by P. O. Fröman, Larsson, and Hökback [J. Math. Phys. 40, 1764–1779 (1999)] is particularized and modified in order to make it adapted to the solution of the differential equations of the two-center Coulomb problem. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2187-2201 
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    Notes: We investigate relations between Uhlmann's parallelism, monotone Riemannian metrics and dual affine connections on the space of density matrices. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2180-2186 
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    Notes: We introduce a new, more general type of nonlinear gauge transformation in nonrelativistic quantum mechanics that involves derivatives of the wave function and belongs to the class of Bäcklund transformations. These transformations satisfy certain reasonable, previously proposed requirements for gauge transformations. Their application to the Schrödinger equation results in higher order partial differential equations. As an example, we derive a general family of sixth-order nonlinear Schrödinger equations, closed under our nonlinear gauge group. We also introduce a new gauge invariant current σ=ρ∇Δ ln ρ, where ρ=ψ¯ψ. We derive gauge invariant quantities, and characterize the subclass of the sixth-order equations that is gauge equivalent to the free Schrödinger equation. We relate our development to nonlinear equations studied by Doebner and Goldin, and by Puszkarz. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2202-2213 
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    Notes: We derive an exact (differential) evolution equation for a class of SU(2) quasiprobability distribution functions. Linear and quadratic cases are considered as well as the quasiclassical limit of the large dimension of representation, S(very-much-greater-than)1. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2241-2248 
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    Notes: We construct a kind of annihilation–creation operators related to the affine coherent states. Next, we re-interpret them as annihilation–creation operators associated with the irreducible unitary representation of the algebra su(1,1), by adding another generator to the two generators of the unitary representation of the one-dimensional affine group. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2214-2240 
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    Notes: An attempt is made to clarify the ballistic nonlinear sigma model formalism recently proposed for quantum chaotic systems, by looking at the spectral determinant Z(s)=Det(1−sU) for quantized maps U∈U(N), and studying the correlator ωU(s)=∫dθ|Z(eiθs)|2. By identifying U(N) as one member of a dual pair acting in the spinor representation of Spin(4N), the expansion of ωU(s) in powers of s2 is shown to be a decomposition into irreducible characters of U(N). In close analogy with the ballistic nonlinear sigma model, a coherent-state integral representation of ωU(s) is developed. For generic U this integral has (N2N) saddle points and the leading-order saddle-point approximation turns out to reproduce ωU(s) exactly, up to a constant factor. This miracle is explained by interpreting ωU(s) as a character of U(2N), and arguing that the leading-order saddle-point result corresponds to the Weyl character formula. Unfortunately, the Weyl decomposition behaves nonsmoothly in the semiclassical limit N→∞, and to make further progress some additional averaging needs to be introduced. Several schemes are investigated, including averaging over basis states and an "isotropic" average. The saddle-point approximation applied in conjunction with these schemes is demonstrated to give incorrect results in general, one notable exception being a semiclassical averaging scheme, for which all loop corrections vanish identically. As a side product of the dual pair decomposition with isotropic averaging, the crossover between the Poisson and CUE limits is obtained. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2284-2305 
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    Notes: We demonstrate how one can describe explicitly the present arbitrariness in solutions of relativistic wave equations in external electromagnetic fields of special form. This arbitrariness is connected to the existence of a transformation, which effectively reduces the number of variables in the initial equations. Then we use the corresponding representations to construct new sets of exact solutions, which may have a physical interest. Namely, we present new sets of stationary and nonstationary solutions in magnetic field and in some superpositions of electric and magnetic fields. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2249-2283 
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    Notes: This paper concerns a relationship between the kernel of the Bargmann transform and the corresponding canonical transformation. We study this fact for a Bargmann transform introduced by Thomas and Wassell [J. Math. Phys. 36, 5480–5505 (1995)]—when the configuration space is the two-sphere S2 and for a Bargmann transform that we introduce for the three-sphere S3. It is shown that the kernel of the Bargmann transform is a power series in a function which is a generating function of the corresponding canonical transformation (a classical analog of the Bargmann transform). We show in each case that our canonical transformation is a composition of two other canonical transformations involving the complex null quadric in C3 or C4. We also describe quantizations of those two other canonical transformations by dealing with spaces of holomorphic functions on the aforementioned null quadrics. Some of these quantizations have been studied by Bargmann and Todorov [J. Math. Phys. 18, 1141–1148 (1977)] and the other quantizations are related to the work of Guillemin [Integ. Eq. Operator Theory 7, 145–205 (1984)]. Since suitable infinite linear combinations of powers of the generating functions are coherent states for L2(S2) or L2(S3), we show finally that the studied Bargmann transforms are actually coherent states transforms. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2306-2347 
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    Notes: We discuss in this article the canonical structure of classical field theory in finite dimensions within the pataplectic Hamiltonian formulation, where we put forward the role of Legendre correspondence. We define the generalized Poisson p-brackets which are the analogs of the Poisson bracket on forms. We formulate the equations of motion of forms in terms of p-brackets. As illustration of our formalism we present three examples: the interacting scalar fields, conformal string theory and the electromagnetic field. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2348-2354 
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    Notes: We perform the Batalin–Vilkovisky quantization of Yang–Mills theory on a two-point space, discussing the formulation of Connes–Lott as well as Connes' real spectral triple approach. Despite the model's apparent simplicity the gauge structure reveals infinite reducibility and the gauge fixing is afflicted with the Gribov problem. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2355-2362 
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    Notes: We study self-dual multivortex solutions of Chern–Simons Higgs theory in a background curved space–time. The existence and decaying property of a solution are demonstrated.© 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2363-2393 
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    Notes: We prove local existence and uniqueness of static spherically symmetric solutions of the Einstein–Yang–Mills (EYM) equations for an arbitrary compact semisimple gauge group in the so-called regular case. By this we mean the equations obtained when the rotation group acts on the principal bundle on which the Yang–Mills connection takes its values in a particularly simple way (the only one ever considered in the literature). The boundary value problem that results for possible asymptotically flat soliton or black hole solutions is very singular and just establishing that local power series solutions exist at the center and asymptotic solutions at infinity amounts to a nontrivial algebraic problem. We discuss the possible field equations obtained for different group actions and solve the algebraic problem on how the local solutions depend on initial data at the center and at infinity. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2439-2465 
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    Notes: This work investigates some global questions about cosmological space–times with two-dimensional spherical, plane, and hyperbolic symmetry containing "well-behaved" matter. The result is that these space–times admit a global foliation by prescribed mean curvature surfaces, which extends at least toward a crushing singularity. The time function of the foliation is geometrically defined and unique up to the choice of an initial Cauchy surface. This work generalizes a similar analysis on constant mean curvature foliations and avoids the topological obstructions arising from the existence problem. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2394-2422 
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    Notes: The scattering theory of Lax and Phillips, originally developed for classical wave equations, has recently been extended to the description of the evolution of resonant states in the framework of quantum theory. The resulting evolution law of the unstable system is that of a semigroup, and the resonant state is a well-defined function in the Lax–Phillips Hilbert space. In this paper we apply this theory to a relativistically covariant quantum field theoretical form of the two (or more) channel relativistic quantum field theoretical form of the Lee model. We show that this theory provides a rigorous underlying basis for the Lee–Oehme–Yang–Wu construction. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2423-2438 
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    Notes: Technical results are presented on motion in N(〉4)D manifolds to clarify the physics of brane theory, Kaluza–Klein theory, induced-matter theory, and string theory. The so-called canonical or warp metric in five dimensions (5D) effectively converts the manifold from a coordinate space to a momentum space, resulting in a new force (per unit mass) parallel to the four-dimensional (4D) velocity. The form of this extra force is actually independent of the form of the metric, but for an unbound particle is tiny because it is set by the energy density of the vacuum or cosmological constant. It can be related to a small change in the rest mass of a particle, and can be evaluated in two convenient gauges relevant to gravitational and quantum systems. In the quantum gauge, the extra force leads to Heisenberg's relation between increments in the position and momenta. If the 4D action is quantized then so is the higher-dimensional part, implying that particle mass is quantized, though only at a level of 10−65 g or less, which is unobservably small. It is noted that massive particles which move on timeline paths in 4D can move on null paths in 5D. This agrees with the view from inflationary quantum field theory, that particles acquire mass dynamically in 4D but are intrinsically massless. A general prescription for dynamics is outlined, wherein particles move on null paths in an N(〉4)D manifold which may be flat, but have masses set by an embedded 4D manifold which is curved. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2466-2485 
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    Notes: This paper is devoted to the investigation of global properties of prescribed mean curvature (PMC) foliations in cosmological space–times with local U(1)×U(1) symmetry and matter described by the Vlasov equation. It turns out that these space–times admit a global foliation by PMC surfaces as well, but the techniques to achieve this goal are more complex than in the cases considered in Paper I [Henkel (2002)]. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2505-2517 
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    Notes: A general notion of bi-quasi-Hamiltonian systems is introduced and is related to previous work on various special cases of such systems. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2518-2522 
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    Notes: Let S:[0,1]→[0,1] be a nonsingular chaotic map that preserves an integrable density f* that describes the statistics of the orbits. In this article we use the maximum entropy approach to approximate the density f* and the corresponding Lyapunov exponent. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2486-2504 
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    Notes: In this article we construct and analyze new classes of wormhole and flux tubelike solutions for the 5D vacuum Einstein equations. These 5D solutions possess generic local anisotropy which gives rise to a gravitational running or scaling of the Kaluza–Klein "electric" and "magnetic" charges of these solutions. It is also shown that it is possible to self-consistently construct these anisotropic solutions with various rotational 3D hypersurface geometries (i.e., ellipsoidal, cylindrical, bipolar and toroidal). The local anisotropy of these solutions is handled using the technique of anholonomic frames with their associated nonlinear connection structures [S. Vacaru, Ann. Phys. (N.Y.) 256, 39 (1997); Nucl. Phys. B 434, 590 (1997); J. Math. Phys. 37, 508 (1996); J. High Energy Phys. 09: 011 (1998); Phys. Lett. B 498, 74 (2001)]. Through the use of the anholonomic frames the metrics are diagonalized, in contrast to holonomic coordinate frames where the metrics would have off-diagonal components. In the local isotropic limit these solutions are shown to be equivalent to spherically symmetric 5D wormhole and flux tube solutions. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2523-2546 
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    Notes: Inspired by the results of Jonas, Einsenhart, Demoulin, and Bianchi on the permutability property of classical geometrical transformations of conjugate nets and its reductions—of pseudo-orthogonal, pseudo-symmetric, and pseudo-Egorov types—dressing transformations of the N-component KP hierarchy (described within the Grassmannian) are used to generate quadrilateral lattices and its corresponding reductions. As a byproduct we get the corresponding discrete dressing transformations; in particular, we characterize the vectorial fundamental discrete transformations preserving the symmetric lattice. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2606-2609 
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    Notes: The duality approach in two-dimensional two-component regular checkerboards is extended to piezoelectricity and piezomagnetism. The relation between the effective piezoelectric and piezomagnetic moduli is found for a checkerboard with the p6′mm′-plane symmetry group (dichromatic triangle). © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2547-2586 
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    Notes: This article is devoted to the systematic study of additional (non-isospectral) symmetries of constrained (reduced) supersymmetric integrable hierarchies of KP type—the so-called SKP(R;MB,MF) models. The latter are supersymmetric extensions of ordinary constrained KP hierarchies which contain as special cases basic integrable systems such as (m)KdV, AKNS, Fordy–Kulish, Yajima–Oikawa, etc. As a first main result it is shown that any SKP(R;MB,MF) hierarchy possesses two different mutually (anti-)commuting types of superloop superalgebra additional symmetries corresponding to the positive- and negative-grade parts of certain superloop superalgebras. The second main result is the systematic construction of the full algebra of additional Virasoro symmetries of SKP(R;MB,MF) hierarchies, which requires nontrivial modifications of the Virasoro flows known from the general case of unconstrained Manin–Radul super-KP hierarchies (the latter flows do not define symmetries for constrained SKP(R;MB,MF) hierarchies). As a third main result we provide systematic construction of the supersymmetric analogs of multi-component (matrix) KP hierarchies and show that the latter contain, among others, the supersymmetric version of the Davey–Stewartson system. Finally, we present an explicit derivation of the general Darboux–Bäcklund solutions for the SKP(R;MB,MF) super-tau functions (supersymmetric "soliton"-like solutions) which preserve the additional (non-isospectral) symmetries. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2587-2605 
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    Notes: We present the sequence of parametrically driven discrete nonlinear Schrödinger systems with the progressively extending range of intersite couplings. In the case of time-independent coupling parameters the sequence is reduced to the Ablowitz–Ladik hierarchy, which is known to be integrable by the inverse scattering transform. However the models with the time-dependent intersite interactions are shown to be integrable too irrespective of a particular form of time dependencies of coupling parameters. Any of such parametrically driven systems might exhibit rather complex soliton dynamics and is described by the unconserved Hamiltonian function. We reveal an important subclass of parametrically driven systems demonstrating the parametrical localization of soliton dynamics on a confined domain of space. Meanwhile an appropriate choice of time dependencies in intersite interactions allow us to transform the original parametrically driven system into another one but subjected to the linear external potential. As a result the latter system can be readily integrated as well. In particular the peculiarities of Bloch oscillations in the systems with time-independent long range intersite interactions and linear external potential of constant strength are analyzed. In general, regulating the range of intersite couplings, the strengths and time dependencies of coupling parameters, we are able to model a number of physically important quasi-one-dimensional systems. We develop an alternative approach to solve the Marchenko equations permitting one to obtain the multisoliton solutions in the most simple and natural way. Finally, we point out how to reformulate any model in row in terms of corrected amplitudes with the standard Poisson brackets. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2610-2615 
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    Notes: In the early 1950s, Lundquist showed the significance of electromagnetic fields with a vanishing Lorentz force density to magnetohydrostatic fluids. Today, these fields are known as force-free electromagnetic fields. Later that decade, Lüst and Schlüter demonstrated that cosmic magnetic fields are force-free and Chandrasekhar and Kendall then constructed a large class of force-free fields whose electric charge density field is also vanishing. In this article, we constructed force-free fields without assuming that the electric charge density vanishes, and in some cases we established a connection between force-free fields and nonlinear Schrödinger equations. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2616-2626 
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    Notes: Enstrophy is an averaged measure of fluid vorticity. This quantity is particularly important in rotating geophysical flows. We investigate the dynamical evolution of enstrophy for large-scale quasi-geostrophic flows under random wind forcing. We obtain upper bounds on the enstrophy, as well as results establishing its Hölder continuity and describing the small-time asymptotics. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2627-2635 
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    Notes: A family of diffusion-annihilation processes is introduced, which is exactly solvable. This family contains parameters that control the diffusion and annihilation rates. The solution is based on the Bethe ansatz and using special boundary conditions to represent the reaction. The processes are investigated, both on the lattice and on the continuum. Special cases of this family of processes are the simple exclusion process and the drop-push model. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2636-2653 
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    Notes: The exact perturbation approach is used to derive the (seven) elementary correlation lengths and related mass gaps of the two-dimensional dilute A4 lattice model in regime 2− from the Bethe Ansatz solution. This model provides a realization of the integrable φ(1,2) perturbation of the c=〈fraction SHAPE="CASE"〉710 conformal field theory, which is known to describe the off-critical thermal behavior of the tricritical Ising model. The E7 masses predicted from purely elastic scattering theory follow in the approach to criticality. Universal amplitudes for the tricritical Ising model are calculated. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2817-2830 
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    Notes: Compatibility relations in effect algebras and their connections with refinements of the orthogonal partitions of unity are studied. Properties of blocks as maximal sets of compatible elements are discussed. Some special kinds of effect algebras are characterized using properties of compatibility. Using refinements, an additional structure on the effect test spaces is introduced and used to a characterization of different types of effect algebras. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1408-1421 
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    Notes: A bi-Hamiltonian formulation is proposed for triangular systems resulting from perturbations around solutions, from which infinitely many symmetries and conserved functionals of triangular systems can be explicitly constructed, provided that one operator of the Hamiltonian pair is invertible. Through our formulation, four examples of triangular systems are exhibited, which also show that bi-Hamiltonian systems in both lower dimensions and higher dimensions are many and varied. Two of four examples give local 2+1 dimensional bi-Hamiltonian systems and illustrate that multiscale perturbations can lead to higher-dimensional bi-Hamiltonian systems. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1547-1568 
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    Notes: The expressions for 12j coefficients of the both kinds (without and with braiding) of the SU(2) group and the quantum algebra uq(2) are considered. Using Dougall's summation formula of the very well-poised hypergeometric 5F4(1) series and its q-generalization, several fourfold sum formulas [with each sum related to the balanced 5F4(1) or 5φ4 series] for the q-12j coefficients of the second kind (without braiding) are derived. Applying q-generalizations of rearrangement formulas of the very well-poised hypergeometric 6F5(−1) series [which correspond to a new expression for the Clebsch–Gordan coefficients of SU(2) and uq(2)], the new expressions with five sums [of the 4F3(1) and 3F2(1) or 4φ3 and 3φ2 type] are derived for the q-12j coefficients of the first kind (with braiding) instead of the usual expansions in terms of q-6j coefficients. Stretched and doubly stretched q-12j coefficients [as triple, double, or single sums, related to composed or separate hypergeometric 4F3(1) and 5F4(1) or 4φ3 and 5φ4 series and, particularly, to q-9j or q-6j coefficients] are considered.© 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1584-1597 
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    Notes: In this work we establish a relationship between Cartan's geometric approach to third-order ordinary differential equations and the three-dimensional null surface formulation. We then generalize both constructions to allow for caustics and singularities that necessarily arise in these formalisms. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1569-1583 
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    Notes: General solutions of the R(circumflex)TT equation with a maximal number of free parameters in the specrtal decomposition of vector SOq(3) R(circumflex) matrices are implemented to construct modified braid equations (MBE). These matrices conserve the given, standard, group relations of the nine elements of T, but are not constrained to satisfy the standard braid equation (BE). Apart from q and a normalization factor our R(circumflex) contains two free parameters, instead of only one such parameter for deformed unitary algebras studied in a previous paper [Math. QA/0009178] where the nonzero right hand side of the MBE had a linear term proportional to (R(circumflex)(12)−R(circumflex)(23)). In the present case the rhs is, in general, nonlinear. Several particular solutions are given (Sec. II) and the general structure is analyzed (Appendix A). Our formulation of the problem in terms of projectors yields also two new solutions of standard (nonmodified) braid equation (Sec. II) which are further discussed (Appendix B). The noncommutative three-spaces obtained by implementing such generalized R(circumflex) matrices are studied (Sec. III). The role of coboundary R(circumflex) matrices (not satisfying the standard BE) is explored. The MBE and Baxterization are presented as complementary facets of the same basic construction, namely, the general solution of R(circumflex)TT equation (Sec. IV). A new solution is presented in this context. As a simple but remarkable particular case a nontrivial solution of BE is obtained (Appendix B) for q=1. This solution has no free parameter and is not obtainable by twisting the identity matrix. In the concluding remarks (Sec. V), among other points, generalization of our results to SOq(N) is discussed. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1598-1621 
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    Notes: A recently proposed technique to solve a class of second order functional difference equations arising in electromagnetic diffraction theory is further investigated by applying it to a case of intermediate complexity. The proposed approach is conceptually simple and relies on first obtaining well-defined branched solutions to a pair of associated first order difference equations. The construction of these branched expressions leads to an equation system whose solution requires relationships akin to Riemann's bilinear relations for differentials of the first and third kinds; their derivation necessitates the application of Cauchy's theorem on Riemann surfaces of, in this particular instance, genera one and three. Branch-free solutions of the second order difference equation are then obtained by taking appropriate linear combinations of the branched solutions of the first order equations. Analysis and computation demonstrate that the resulting expressions have the desired analytical properties and recover known solutions in the appropriate limit. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 182-204 
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    Notes: We compute the metric associated with noncommutative spaces described by a tensor product of spectral triples. Well-known results of the two-sheets model (distance on a sheet, distance between the sheets) are extended to any product of two spectral triples. The distance between different points on different fibers is investigated. When one of the triples describes a manifold, one finds a Pythagorean theorem as soon as the direct sum of the internal states (viewed as projections) commutes with the internal Dirac operator. Scalar fluctuations yield a discrete Kaluza–Klein model in which the extra component of the metric is given by the internal part of the geometry. In the standard model, this extra component comes from the Higgs field. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 644-650 
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    Notes: We present a new approach for constructing covariant symplectic structures for geometrical theories, based on the concept of adjoint operators. Such geometric structures emerge by direct exterior derivation of underlying symplectic potentials. Differences and similarities with other approaches and future applications are discussed. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 678-683 
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    Notes: We present numerical evidence that singularities form in finite time during the evolution of 2+1 wave maps from spherically equivariant initial data of sufficient energy. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 684-686 
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    Notes: Relative to a given factoring of the Hilbert space, the decomposition of an operator into a convex sum of correlated products of pairs of distinct 1-projectors, one set of projectors linearly independent, is unique. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 687-691 
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    Notes: In this paper the concept of pesudodifferential forms on supermanifolds is extended and a new complex is introduced. At last it is shown that the corresponding cohomology ring is sensitive to "super" structure. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1809-1843 
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    Notes: Semiclassical Hamiltonian field theory is investigated from the axiomatic point of view. A notion of a semiclassical state is introduced. An "elementary" semiclassical state is specified by a set of classical field configurations and quantum states in this external field. "Composed" semiclassical states viewed as formal superpositions of "elementary" states are nontrivial only if the Maslov isotropic condition is satisfied; the inner product of "composed" semiclassical states is degenerate. The mathematical proof of Poincaré invariance of semiclassical field theory is obtained for "elementary" and "composed" semiclassical states. The notion of semiclassical field is introduced; its Poincaré invariance is also mathematically proved. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1755-1795 
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    Notes: Scaling limits of the Hamiltonian H of a system of N charged particles coupled to a quantized radiation field are considered. Ultraviolet cutoffs, λ(circumflex)1,...,λ(circumflex)N, are imposed on the radiation field and the Coulomb gauge is taken. It is the so-called Pauli–Fierz model in nonrelativistic quantum electrodynamics. We mainly consider two cases: (i) all the ultraviolet cutoffs are identical, λ(circumflex)1=(centered ellipsis)=λ(circumflex)N, (ii) supports of ultraviolet cutoffs have no intersection, supp λ(circumflex)i∩supp λ(circumflex)j=&nullset;, i≠j. The Hamiltonian acts on L2(RdN)⊗F, where F is a symmetric Fock space, and has the form H=Hel⊗1+B+1⊗Hquad. Here Hel denotes a particle Hamiltonian, Hquad a quadratic field operator, and B an interaction term. The scaling is introduced as H(κ)=Hel⊗1+κlB+κ21⊗Hquad, where κ is a scaling parameter and l≤2 a parameter of the scaling. Performing a mass renormalization we consider the scaling limit of H(κ) as κ→∞ in the strong resolvent sense. Then effective Hamiltonians Heff in L2(RdN) infected with reaction of effect of the radiation field is derived. In particular (1) effective Hamiltonians with an effective potential for l=2, and (2) effective Hamiltonians with an observed mass for l=1, are obtained. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1844-1855 
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    Notes: We consider quantum systems with variable but finite number of particles. For such systems we develop geometric and commutator techniques. We use these techniques to find the location of the spectrum, to prove absence of singular continuous spectrum, and identify accumulation points of the discrete spectrum. The fact that the total number of particles is bounded allows us to give relatively elementary proofs of these basic results for an important class of many-body systems with nonconserved number of particles. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1856-1874 
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    Notes: We construct multiskyrmion fields of the SU(N) Skyrme models by using harmonic maps of S2 to the Grassmannian Gr(2,N), which we express in terms of rank-2 projectors. Within this construction we derive some approximate spherically symmetric solutions of SU(N) Skyrme models and show that their energies are marginally higher than those for the rank-one cases. We also discuss the possibility of generating exact spherically symmetric solutions using this construction. In particular, we present arguments which suggest that the only solutions obtained in this way are embeddings. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1916-1937 
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    Notes: We consider a real Lagrangian off-critical submodel describing the soliton sector of the so-called conformal affine sl(3)(1) Toda model coupled to matter fields. The theory is treated as a constrained system in the context of Faddeev–Jackiw and the symplectic schemes. We exhibit the parent Lagrangian nature of the model from which generalizations of the sine-Gordon (GSG) or the massive Thirring (GMT) models are derivable. The dual description of the model is further emphasized by providing the relationships between bilinears of GMT spinors and relevant expressions of the GSG fields. In this way we exhibit the strong/weak coupling phases and the (generalized) soliton/particle correspondences of the model. The sl(n)(1) case is also outlined. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1956-1965 
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    Notes: By imposing constraint (Lk)−=q∂−1r∂ on the pseudo-differential operator Lk, the k constrained modified Kadomtsev–Petviashvili (KP) hierarchy and their corresponding Lax pair are obtained from the linear problem and its adjoint of the modified KP system. Especially, the modified KdV system, the GNS system with derivative coupling, the Burgers system, and a new 3×3 integrable system are presented as examples. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1980-1999 
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    Notes: Using representations of sl(2,R) generators which yield associated Lamé Hamiltonians we obtain new classes of elliptic potentials. We explicitly calculate eigenstates and spectra for these potentials and construct the associated orthogonal polynomials. We show that in the proper limit these potentials reduce to well-known exactly solvable potentials. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2000-2014 
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    Notes: Properly specializing the parameters contained in the maximal cyclic representation of the nonrestricted A-type quantum algebra at roots of unity, we find the unique primitive vector in it. In this case, the representation is no longer irreducible. We show that the submodule generated by the primitive vector is the unique irreducible submodule and can be identified with an irreducible highest weight module of the finite dimensional A-type quantum algebra, which is defined as the subalgebra of the restricted quantum algebra at roots of unity. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1966-1979 
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    Notes: The problem of determining the metric for a nonstatic shear-free spherically symmetric fluid (either charged or neutral) reduces to the problem of determining a one-parameter family of solutions to a second-order ordinary differential equation (ODE) containing two arbitrary functions f and g. Choices for f and g are determined such that this ODE admits a one-parameter family of solutions that have poles as their only movable singularities. This property is strictly weaker than the Painlevé property and it is used to identify classes of solvable models. It is shown that this procedure systematically generates many exact solutions including the Vaidya metric, which does not arise from the standard Painlevé analysis of the second-order ODE. Interior solutions are matched to exterior Reissner–Nordstrøm metrics. Some solutions given in terms of second Painlevé transcendents are described. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2015-2028 
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    Notes: The real geometry of holomorphic four-metrics is investigated. The almost product and complex structures, associated with the real eight-metrics corresponding to the real and imaginary parts of the holomorphic metrics, are studied. It is shown that half-flat holomorphic metrics, and the corresponding real eight-metrics, are associated with integrable almost product, complex and hyper-Kähler structures. Real and complex local coordinate descriptions are presented. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 2029-2048 
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    Notes: Corresponding to each finite dimensional simple basic classical Lie superalgebra, a new quantum enveloping superalgebra is introduced, which has the structure of a braided quasi-Hopf superalgebra. In the case of osp(1|2n), this quantum enveloping superalgebra is shown to be isomorphic to the standard Drinfeld–Jimbo quantum superalgebra Uq(osp(1|2n)) as braided quasi Hopf superalgebras. The new quantum enveloping superalgebras are applied to construct link invariants, from which Vassiliev invariants can be readily extracted. This, in particular, provides a useful construction for the Vassiliev invariants associated with Uq(osp(1|2n)). © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1129-1135 
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    Notes: The relativistic J-matrix is investigated in the case of Coulomb-free scattering for a general short-range spin-dependent perturbing potential and in two different L2 bases. The resulting recursion relation of the reference problem, in this case, has an analytic solution. The nonrelativistic limit is obtained and shown to be identical to the familiar nonrelativistic J-matrix.© 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1136-1151 
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    Notes: Motion of Yang–Mills particles in Yang–Mills–Higgs fields are studied. By regarding the Higgs field contribution on the particle's motion, a complete set of equations is worked out for the particle and fields. The planar motions as well as three-dimensional bounded motions are studied. Stable orbits are allowed in this scenario. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1152-1184 
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    Notes: We study spectral and scattering properties of a spinless quantum particle confined to an infinite planar layer with hard walls containing a finite number of point perturbations. A solvable character of the model follows from the explicit form of the Hamiltonian resolvent obtained by means of Krein's formula. We prove the existence of bound states, demonstrate their properties, and find the on-shell scattering operator. Furthermore, we analyze the situation when the system is put into a homogeneous magnetic field perpendicular to the layer; in that case the point interactions generate eigenvalues of a finite multiplicity in the gaps of the free Hamiltonian essential spectrum. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1185-1210 
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    Notes: This article deals with the comparison between the strong Thomas–Fermi theory and the quantum mechanical ground state energy of a large atom confined to lowest Landau band wave functions. Using the tools of microlocal semiclassical spectral asymptotics we derive precise error estimates. The approach presented in this article suggests the definition of a modified strong Thomas–Fermi functional, where the main modification consists in replacing the integration over the variables perpendicular to the magnetic field by an expansion in angular momentum eigenfunctions. The resulting DSTF theory is studied in detail in the second part of the article. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1247-1260 
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    Notes: It is conjectured that the Holevo capacity of a product channel Ω⊗Φ is achieved when product states are used as input. Amosov, Holevo, and Werner have also conjectured that the maximal lp norm of a product channel is achieved with product input states. In this article we establish both of these conjectures in the case that Ω is arbitrary and Φ is a CQ or QC channel (as defined by Holevo). We also establish the Amosov, Holevo and Werner conjecture when Ω is arbitrary and either Φ is a qubit channel and p=2, or Φ is a unital qubit channel and p is integer. Our proofs involve a new conjecture for the norm of an output state of the half-noisy channel I⊗Φ, when Φ is a qubit channel. We show that this conjecture in some cases also implies additivity of the Holevo capacity. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1261-1272 
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    Notes: In this paper, we prove that for fields close to the lower critical field, minimizers of the Ginzburg–Landau functional of an inhomogeneous superconductor have a number of vortices bounded independently from the Ginzburg–Landau parameter. We also locate the vortices. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1299-1308 
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    Notes: We study the mathematical structure of covariant phase observables. Such observables can alternatively be expressed as phase matrices, as sequences of unit vectors, as sequences of phase states, or as equivalence classes of covariant trace-preserving operations. Covariant generalized operator measures are defined by structure matrices which form a W*-algebra with phase matrices as its subset. The properties of the Radon–Nikodým derivatives of phase probability measures are studied. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1273-1298 
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    Notes: Singular perturbation theory for quantum mechanics is considered in a framework generalizing the spectral concentration theory. Under very general conditions, asymptotic estimations on the Rayleigh–Schrödinger expansions of the perturbed spectral projections are obtained. As a consequence almost invariant subspaces of exponential order are constructed. The results cover practically all singular perturbations considered in nonrelativistic quantum mechanics. In the magnetic field case, under the condition that the magnetic field does not increase at infinity, a gauge invariant perturbation theory leading to convergent series with field-dependent coefficients is developed. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1309-1322 
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    Notes: A family of maximally superintegrable systems containing the Coulomb atom as a special case is constructed in n-dimensional Euclidean space. Two different sets of n commuting second-order operators are found, overlapping in the Hamiltonian alone. The system is separable in several coordinate systems and is shown to be exactly solvable. It is solved in terms of classical orthogonal polynomials. The Hamiltonian and n further operators are shown to lie in the enveloping algebra of a hidden affine Lie algebra. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1323-1339 
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    Notes: The theory of fiber bundles provides a natural setting for the description of macroscopic quantum systems, wherein their classical and quantum features are represented by actions on the base manifolds and the fibers, respectively, of the relevant bundles. We provide realizations of this picture in the description of (a) quasiparticle excitations of many-body systems, especially those in superfluid helium, (b) the interplay between the microscopic and macroscopic dynamics in certain irreversible processes, such as that of a laser, and (c) local thermodynamic equilibrium. In particular, (b) involves the treatment of a dynamical system which is defined on a vector bundle. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1340-1352 
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    Notes: In this paper we study the large Nc limit of SO(Nc) gauge theory coupled to a real scalar field following ideas of Rajeev [Int. J. Mod. Phys. A 9, 5583 (1994)]. We will see that the phase space of this resulting classical theory is Sp1(H)/U(H+) which is the analog of the Siegel disk in infinite dimensions. The linearized equations of motion give us a version of the well-known 't Hooft equation of two dimensional quantum chromodynamics. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1353-1364 
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    Notes: We show the emergence of Clifford algebras of nonsymmetric bilinear forms as cotangent algebras of Kaluza–Klein (KK) spaces pertaining to teleparallel space–times. These spaces are canonically determined by the horizontal differential invariants of Finsler bundles of the type, B′(M)→S(M), where B′(M) is the set of all the tangent frames to a differentiable manifold M, and where S(M) is the sphere bundle. If M is space–time itself, M4, the "geometric phase space," S(M4), has dimension seven. This reformulation of the horizontal invariants as pertaining to a KK space removes the mismatch between the dimensionality of the tangent frames to M4 and the dimensionality of S(M4). In the KK space, a symmetric tangent metric induces a cotangent metric which is not symmetric in general. An interior covariant derivative in the sense of Kaehler is defined. It involves the antisymmetric part of the cotangent metric, which thus enters electrodynamics and the Dirac equation. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1390-1407 
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    Notes: We consider an arbitrary translationally invariant chain model with nearest neighbors interaction and satisfying periodic boundary condition. The approach developed here allows a thermodynamic description of the chain model directly in terms of grand potential per site. This thermodynamic function is derived from an auxiliary function constructed only from open connected subchains. In order to exemplify its application and how this approach works we consider the Heisenberg XXZ model. We obtain the coefficients of the high temperature expansion of the free energy per site of the model up to third order. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1365-1389 
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    Notes: We classify (1+3)-dimensional Pauli equations for a spin-〈fraction SHAPE="CASE"〉12 particle interacting with the electro-magnetic field, that are solvable by the method of separation of variables. As a result, we obtain the 11 classes of vector-potentials of the electro-magnetic field A(t,x(vector))=(A0(t,x(vector)), A(vector)(t,x(vector))) providing separability of the corresponding Pauli equations. It is established, in particular, that the necessary condition for the Pauli equation to be separable into second-order matrix ordinary differential equations is its equivalence to the system of two uncoupled Schrödinger equations. In addition, the magnetic field has to be independent of spatial variables. We prove that coordinate systems and the vector-potentials of the electro-magnetic field providing the separability of the corresponding Pauli equations coincide with those for the Schrödinger equations. Furthermore, an efficient algorithm for constructing all coordinate systems providing the separability of Pauli equation with a fixed vector-potential of the electro-magnetic field is developed. Finally, we describe all vector-potentials A(t,x(vector)) that (a) provide the separability of Pauli equation, (b) satisfy vacuum Maxwell equations without currents, and (c) describe non-zero magnetic field. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1422-1440 
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    Notes: We present a new and effective method of determining separable coordinate systems for natural Hamiltonians with two degrees of freedom in flat Riemannian space. The method is based on intrinsic properties of the associated Killing tensors and their invariants under the group of rigid motions E(2). Applications to the Hamiltonian systems derived by the late V. A. Yatsun from O(4)-symmetric Yang–Mills theories are presented. In addition, an equivalence between separability of two-dimensional Hamiltonian systems and the existence of Pfaffian quasi-bi-Hamiltonian representations is specified. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1441-1459 
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    Notes: We propose a general scheme to construct multiple Lagrangians for completely integrable nonlinear evolution equations that admit multi-Hamiltonian structure. The recursion operator plays a fundamental role in this construction. We use a conserved quantity higher/lower than the Hamiltonian in the potential part of the new Lagrangian and determine the corresponding kinetic terms by generating the appropriate momentum map. This leads to some remarkable new developments. We show that nonlinear evolutionary systems that admit N-fold first order local Hamiltonian structure can be cast into variational form with 2N−1 Lagrangians which will be local functionals of Clebsch potentials. This number increases to 3N−2 when the Miura transformation is invertible. Furthermore we construct a new Lagrangian for polytropic gas dynamics in 1+1 dimensions which is a free, local functional of the physical field variables, namely density and velocity, thus dispensing with the necessity of introducing Clebsch potentials entirely. This is a consequence of bi-Hamiltonian structure with a compatible pair of first and third order Hamiltonian operators derived from Sheftel's recursion operator. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1460-1486 
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    Notes: The Riemann–Hilbert problem associated with the integrable PDE is used as a nonlinear transformation of the nearly integrable PDE to the spectral space. The temporal evolution of the spectral data is derived with account for arbitrary perturbations and is given in the form of exact equations, which generate the sequence of approximate ordinary differential equations in successive orders with respect to the perturbation. For vector nearly integrable PDEs, embracing the vector nonlinear Schrödinger and complex modified Korteweg–de Vries equations, the main result is formulated in a theorem. For a single vector soliton the evolution equations for the soliton parameters and first-order radiation are given in explicit form. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1622-1645 
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    Notes: In this paper we provide a complete classification of the Darboux invariants, of the irreducible Darboux polynomials, of the rational first integrals and of the algebraic integrability for the classical Lorenz system x(overdot)=s(y−x), y(overdot)=rx−y−xz, z(overdot)=−bz+xy. In the proofs, we use the weight homogeneous polynomials and the method of characteristic curves for solving linear partial differential equations. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1646-1663 
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    Notes: As an alternative to Chevalley generators, we introduce Jacobson generators for the quantum superalgebra Uq[sl(n+1|m)]. The expressions of all Cartan–Weyl elements of Uq[sl(n+1|m)] in terms of these Jacobson generators become very simple. We determine and prove certain triple relations between the Jacobson generators, necessary for a complete set of supercommutation relations between the Cartan–Weyl elements. Fock representations are defined, and a substantial part of this paper is devoted to the computation of the action of Jacobson generators on basis vectors of these Fock spaces. It is also determined when these Fock representations are unitary. Finally, Dyson and Holstein–Primakoff realizations are given, not only for the Jacobson generators, but for all Cartan–Weyl elements of Uq[sl(n+1|m)]. © 2002 American Institute of Physics.
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    Journal of Mathematical Physics 43 (2002), S. 1664-1667 
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    Source: AIP Digital Archive
    Topics: Mathematics , Physics
    Notes: Using Darling's theorem on products of generalized hypergeometric series, an analytic expression is obtained for the Coulomb matrix elements in the lowest Landau level in the representation of angular momentum. The result is important in the studies of fractional quantum Hall effect (FQHE) in disk geometry. Matrix elements are expressed as simple finite sums of positive terms, eliminating the need to approximate these quantities with slowly convergent series. As a by-product, an analytic representation for certain integrals of products of Laguerre polynomials is obtained. © 2002 American Institute of Physics.
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  • 98
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 43 (2002), S. 1668-1674 
    ISSN: 1089-7658
    Source: AIP Digital Archive
    Topics: Mathematics , Physics
    Notes: A generalized oscillator algebra is proposed and the braided Hopf algebra structure for this generalized oscillator is investigated. Using the solutions for the braided Hopf algebra structure, two types of braided Fibonacci oscillators are introduced. This leads to two types of braided Biedenharn–Macfarlane oscillators as special cases of the Fibonacci oscillators. We also find the braided Hopf algebra solutions for the three dimensional braided space. One of these, as a special case, gives the Hopf algebra given in the literature. © 2002 American Institute of Physics.
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  • 99
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 43 (2002), S. 1008-1017 
    ISSN: 1089-7658
    Source: AIP Digital Archive
    Topics: Mathematics , Physics
    Notes: In this paper, five 2+1 dimensional lattices considered by several authors are revisited again. First of all we will show that two lattices proposed by Blaszak and Szum [J. Math. Phys. 42, 225 (2001)] become the so-called differential-difference KP equation due to Date, Jimbo, and Miwa [J. Phys. Soc. Jpn. 51, 4116 (1982); 51, 4125 (1982); 52, 388 (1983); 52, 761 (1983); 52, 766 (1983)] by simple variable transformations, while another lattice found by Blaszak and Szum can be viewed as a higher-dimensional generalization of a lattice given by Wu and Hu [J. Phys. A 32, 1515 (1999)]. Some integrable properties on these three lattices are derived. Second, it is shown that a 2+1 dimensional Toda-like lattice studied by Cao, Geng, and Wu [J. Phys. A 32, 8059 (1999)] can be transformed into the bilinear equation given by Hu, Clarkson, and Bullough [J. Phys. A 30, L669 (1997)]. For this bilinear version we also present some rational solutions and Lie symmetries. Finally, a lattice due to Levi, Ragnisco, and Shabat [Can. J. Phys. 72, 439 (1994)] is transformed into coupled bilinear equations. It is shown that these coupled bilinear equations do not have two-soliton solutions. This further confirms that the lattice under consideration is not completely integrable. © 2002 American Institute of Physics.
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  • 100
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 43 (2002), S. 1029-1043 
    ISSN: 1089-7658
    Source: AIP Digital Archive
    Topics: Mathematics , Physics
    Notes: It is shown that different approaches toward the solution of the Einstein equations for a static spherically symmetric perfect fluid with a γ-law equation of state lead to an Abel differential equation of the second kind. Its only integrable cases at present are flat space–time, de Sitter solution and its Buchdahl transform, Einstein static universe, and the Klein–Tolman solution. © 2002 American Institute of Physics.
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