http://en.redtram.com/ News on "Mathematics"  everywhere Copyright (c) 2009 RedTram. All rights reserved. webmaster@redtram.com (RedTram) en Thu, 17 Dec 2009 02:15:12 GMT 300 100 50 http://en.redtram.com/ http://img.en.redtram.com/rsslogo.gif 6593 | Fluid Models from Kinetic Theory using Geometric Averaging. (arXiv:0912.2767v1 [math-ph]) http://en.redtram.com/go/236285664/top100/ 236285664 Using a geometric averaging procedure applied to a non-affine linearconnection obtained from the Lorentz force equation, we prove that for narrowone particle distribution functions and in the ultra-relativistic limit, abunch of charged point particles can be described by a Charged Wed, 16 Dec 2009 07:12:18 GMT http://en.redtram.com/go/236285664/top100/ 6593 | Exact Fermi coordinates for a class of spacetimes. (arXiv:0912.2779v1 [math-ph]) http://en.redtram.com/go/236285657/top100/ 236285657 We find exact Fermi coordinates for timelike geodesic observers for a classof spacetimes that includes anti-de Sitter spacetime, de Sitter spacetime, theconstant density interior Schwarzschild spacetime with positive, zero, andnegative cosmological constant, and the Einstein static universe. Maximalcharts for Fermi Wed, 16 Dec 2009 07:11:41 GMT http://en.redtram.com/go/236285657/top100/ 6593 | KAM theory in configuration space and cancellations in the Lindstedt series. (arXiv:0912.2836v1 [math.DS]) http://en.redtram.com/go/236285647/top100/ 236285647 The KAM theorem for analytic quasi-integrable anisochronous Hamiltoniansystems yields that the perturbation expansion (Lindstedt series) forquasi-periodic solutions with Diophantine frequency vector converges. If onestudies the Lindstedt series, one finds that convergence is ultimately relatedto the presence of cancellations between contributions Wed, 16 Dec 2009 07:11:19 GMT http://en.redtram.com/go/236285647/top100/ 6593 | Higher-order Abel equations: Lagrangian formalism, first integrals and Darboux polynomials. (arXiv:0912.2842v1 [math-ph]) http://en.redtram.com/go/236285640/top100/ 236285640 A geometric approach is used to study a family of higher-order nonlinear Abelequations. The inverse problem of the Lagrangian dynamics is studied in theparticular case of the second-order Abel equation and the existence of twoalternative Lagrangian formulations is proved, both Wed, 16 Dec 2009 07:10:53 GMT http://en.redtram.com/go/236285640/top100/ 6593 | Quasi-exactly solvable models as constrained systems. (arXiv:0912.2857v1 [math-ph]) http://en.redtram.com/go/236285634/top100/ 236285634 We discuss a universal algebraic approach to quasi-exactly solvable modelswhich allows us to interpret them as constrained Hamiltonian systems with afinite number of physical states. Using this approach we reproduce well-knowntwo-dimensional Lie-algebraic quasi-exactly solvable system based on Liealgebra su(3). Wed, 16 Dec 2009 07:10:42 GMT http://en.redtram.com/go/236285634/top100/ 6593 | The calculus of the electric potential and field intensity in multiple electrodes lateral tunneling transistors with double gate. (arXiv:0912.2878v1 [math-ph]) http://en.redtram.com/go/236285629/top100/ 236285629 The paper presents an adaptive over-relaxation method for calculating theelectric potential and field intensity, for a complex tunnel transistorstructure involving a split gate and a shielding boundary. The accuracy andspeed of the method has been numerically tested and found satisfactory Wed, 16 Dec 2009 07:10:32 GMT http://en.redtram.com/go/236285629/top100/ 6593 | Optimal basis set for ab-initio calculations of energy levels in tunneling structures, using the covariance matrix of the wave functions. http://en.redtram.com/go/236285620/top100/ 236285620 The paper proposes a method to obtain the optimal basis set for solving theself consistent field (SCF) equations for large atomic systems in order tocalculate the energy barriers in tunneling structures, with higher accuracy andspeed. Taking into account the stochastic-like Wed, 16 Dec 2009 07:10:05 GMT http://en.redtram.com/go/236285620/top100/ 6593 | Global Controllability of Multidimensional Rigid Body by Few Torques. (arXiv:0912.2900v1 [math.OC]) http://en.redtram.com/go/236285616/top100/ 236285616 We study global controllability of 'rotating' multidimensional rigid body(MRB) controlled by application of few torques. Study by methods of geometriccontrol requires analysis of algebraic structure introduced by the quadraticterm of Euler-Frahm equation. We discuss problems, which arise in the course Wed, 16 Dec 2009 07:09:51 GMT http://en.redtram.com/go/236285616/top100/ 6593 | Nonlocal potentials and complex angular momentum theory. (arXiv:0912.2902v1 [math-ph]) http://en.redtram.com/go/236285610/top100/ 236285610 The purpose of this paper is to establish meromorphy properties of thepartial scattering amplitude T(lambda,k) associated with physically relevantclasses N_{w,alpha}^gamma of nonlocal potentials in corresponding domainsD_{gamma,alpha}^delta of the space C^2 of the complex angular momentum lambdaand of the complex momentum Wed, 16 Dec 2009 07:09:33 GMT http://en.redtram.com/go/236285610/top100/ 6593 | Bott periodicity and stable quantum classes. (arXiv:0912.2948v1 [math.SG]) http://en.redtram.com/go/236285604/top100/ 236285604 We use Bott periodicity to relate previously defined quantum classes tocertain "exotic Chern classes" on $BU$. This provides a remarkablecomputational and theoretical framework for some Gromov-Witten invariantsconnected with cohomological field theories, and is intimately connected tostudy of Gromov K-area, to Wed, 16 Dec 2009 07:09:14 GMT http://en.redtram.com/go/236285604/top100/ 6593 | HAM and HPM: Another attack to reason. (arXiv:0912.2973v1 [math-ph]) http://en.redtram.com/go/236285595/top100/ 236285595 We discuss two recent applications of homotopy analysis method and homotopyperturbation method and conclude that the results are completely useless fromboth mathematical and physical points of view. Wed, 16 Dec 2009 07:08:35 GMT http://en.redtram.com/go/236285595/top100/ 6593 | New recursive residue formulas for the topological expansion of the Cauchy Matrix Model. (arXiv:0912.2984v1 [math-ph]) http://en.redtram.com/go/236285589/top100/ 236285589 In a recent work [1] we consider the topological expansion for the non-mixedobservables (including the free energy) for the formal Cauchy matrix model. Theonly restriction in [1] was the fact that all the branch points have to besimple. This excludes Wed, 16 Dec 2009 07:08:17 GMT http://en.redtram.com/go/236285589/top100/ 6593 | Order Topology and Frink Ideal Topology of Effect Algebras. (arXiv:0908.3350v2 [math-ph] UPDATED) http://en.redtram.com/go/236285583/top100/ 236285583 In this paper, the following results are proved: (1) $ $ If $E$ is a completeatomic lattice effect algebra, then $E$ is (o)-continuous iff $E$ isorder-topological iff $E$ is totally order-disconnected iff $E$ is algebraic.(2) $ $ If $E$ is Wed, 16 Dec 2009 07:07:56 GMT http://en.redtram.com/go/236285583/top100/ 6593 | On the Lagrangian structure of integrable quad-equations. (arXiv:0912.2464v1 [nlin.SI] CROSS LISTED) http://en.redtram.com/go/236285575/top100/ 236285575 The new idea of flip invariance of action functionals in multidimensionallattices was recently highlighted as a key feature of discrete integrablesystems. Lobb and Nijhoff proved flip invariance for several particular casesof integrable quad-equations. We provide a simple and case-independent prooffor Wed, 16 Dec 2009 07:07:35 GMT http://en.redtram.com/go/236285575/top100/