摘要:

AbstractLipschitz‐Killing curvatures of piecewise flat spaces are combinatorial analogues of Lipschitz‐Killing curvatures of Riemannian manifolds. In the following paper rigorous combinatorial representations and proofs of all basic results for Lipschitz‐Killing curvatures not using analytic arguments are given. The principal tools for an elementary representation of Regge calculus can be developed by means of basic properties of dihedral a

ISSN:0003-3804    

DOI:10.1002/andp.19895010102

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractWe give a short discussion of usual representation of geometric approach to modern continuum mechanics. As a consequence we propose a formulation of this theorie based on the internal quasi‐Lorentz‐group. The aim of our method is to get an unitary geometrisation of the theory of condensed structures. The result is: For an internal observer the theory of the real solid is the theory of totally geodesic three‐dimensional hypersurfaces in a genuin four‐dimensional non Riemannian “sound sp

ISSN:0003-3804    

DOI:10.1002/andp.19895010103

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractAn appropriate approach is presented for solving the Boltzmann equation for electron swarms and nonstationary weakly ionized plasmas in the hydrodynamic stage, including ionization and attachment processes. Using a Legendre‐polynomial expansion of the electron velocity distribution function the resulting eigenvalue problem has been solved at any even truncation‐order. The technique has been used to study velocity distribution, mean collision frequencies, energy transfer rates, nonstationary behaviour and power balance in hydrodynamic stage, of electrons in a model plasma and a plasma of pure SF6.The calculations have been performed for increasing approximation‐orders, up to the converged solution of the problem.In particular, the transition from dominant attachment to prevailing ionization when increasing the field strength has been studied.Finally the establishment of the hydrodynamic stage for a selected case in the model plasma has been investigated by solving the nonstationary, spatially homogeneous Boltzmann equation in twoterm approxim

ISSN:0003-3804    

DOI:10.1002/andp.19895010104

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractIn the framework of Weyl invariant gravitational field theory including torsion coupled to a scalar field with arbitrary selfinteraction it will be shown that any solution of such a generalized Goldstone model contains the conformally invariant field of a massless scalar particle. Due to this fact it may happen that dynamical symmetry breaking becomes impossible.

ISSN:0003-3804    

DOI:10.1002/andp.19895010105

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractOn the basis of the attractive Hubbard model with a Gaussian random potential we describe superconductivity in the presence of quenched disorder. A dynamic path‐integral formalism with an 8‐component Keldysh‐Nambu spinor is shown to be convenient for solving the averaging problem without the recourse to the replica trick. The effective action is bosonized in terms of collective variables, namely localQ‐matrices and real space pair fields. Saddle point values are calculated in two simplified

ISSN:0003-3804    

DOI:10.1002/andp.19895010106

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractWe consider the integro‐differential equation for the classical trajectory of an oscillator coupled to another one. On the quantum level the elimination of the coordinateAof the “unvisible” oscillator leads to an effective path integral (X, Ξ, μ) for the associated imaginary time stochastic processtϵ, (‐∞,∞) →x(t). We prove reflection positivity of the measuredμ ≈F·dξ, wheredξ governes the free oscillatorxandFis the counterpart of Feynman's influence functional. Finally, realizing the Hamiltonian semigroup exp(‐tH),t≧ 0, in the physical Hilbert space ℋ︁ =L2(X, Γ, μ), where Γ ⊆ Ξ+,

ISSN:0003-3804    

DOI:10.1002/andp.19895010107

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractConcepts connected with Berry's phase can be extended to curves and loops in state spaces defined by von Neumann algebras. This includes the important space of density operators.

ISSN:0003-3804    

DOI:10.1002/andp.19895010108

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractWir lenken die Aufmerksamkeit darauf, daß die kanonische ZustandsummeZ(β1, β2, …, βn) ≡Z(β) eines ausnunabhängigen Teilsystemen zusammengesetzten thermodynamischen Systems eine schurkonvexe Funktion ist. Dabei bezeichnet βidie inverse Temperatur desi‐ten Teilsystems. Falls die innere Energie proportional zu β ist ‐ wie etwa bei Spinsystemen in Hochtemperatur‐Näherung ‐ so folgt aus der Schurkonvexität, daß beliebiger Temperaturausgleich zwischen den Teilsystemen stets zu einem

ISSN:0003-3804    

DOI:10.1002/andp.19895010109

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

ISSN:0003-3804    

DOI:10.1002/andp.19895010110

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

ISSN:0003-3804    

DOI:10.1002/andp.19895010111

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY