A non-perturbative proof of Bertrand's theoremWe discuss an alternative non-perturbative proof of Bertrand's theorem that leads in a concise way directly to the two allowed fields: the newtonian and the isotropic harmonic oscillator central…F C Santos, V Soares, A C Tort·Apr 4, 2007SaveLearn
Comment on "How the potentials in different gauges yield the same retarded electric and magnetic fields," by J. A. Heras [Am. J. Phys. 75, 176 (2007)]Heras purports to show without solving the requisite dynamic equations how the non-causal term generated by the scalar potential of the Coulomb, Kirchhoff, or velocity gauge is canceled by an equal…V. Hnizdo·Mar 28, 2007SaveLearn
Expansion of a Formalism of Classical Mechanics for Nonequilibrium SystemsThe expansion of a classical Hamilton formalism consisting in adaptation of it to describe the nonequilibrium systems is offered. Expansion is obtained by construction of formalism on the basis of…V. M. Somsikov·Mar 27, 2007SaveLearn
A distributional approach to the geometry of dislocations at the mesoscaleWe develop a theory to represent dislocated single crystals at the mesoscopic scale by considering concentrated effects, governed by the distribution theory combined with multiple-valued kinematic…Nicolas Van Goethem, F. Dupret·Mar 25, 2007SaveLearn
Total Differential Errors in One-Port Network Analyzer Measurements with Application to Antenna ImpedanceThe objective was to study uncertainty in antenna input impedance resulting from full one-port Vector Network Analyzer (VNA) measurements. The VNA process equation in the reflection coefficient p of…Nikolitsa Yannopoulou, Petros Zimourtopoulos·Mar 21, 2007SaveLearn
Dissipative Boussinesq equationsThe classical theory of water waves is based on the theory of inviscid flows. However it is important to include viscous effects in some applications. Two models are proposed to add dissipative…Denys Dutykh, Frédéric Dias·Mar 20, 2007SaveLearn
Force Equation That Describes the Quantum States of a Relativistic Spinless ParticleNewton's second law may be used to obtain a wave equation, which reduces to Schrodinger's equation in the nonrelativistic limit and for a conservative force.C. A. Ordonez·Mar 14, 2007SaveLearn
On the Definition of Effective Permittivity and Permeability For Thin Composite LayersThe problem of definition of effective material parameters (permittivity and permeability) for composite layers containing only one-two parallel arrays of complex-shaped inclusions is discussed. Such…Elena Saenz, Pekka Ikonen, Ramon Gonzalo et al.·Mar 11, 2007SaveLearn
An assessment of Evans' unified field theory IEvans developed a classical unified field theory of gravitation and electromagnetism on the background of a spacetime obeying a Riemann-Cartan geometry. This geometry can be characterized by an…Friedrich W. Hehl·Mar 10, 2007SaveLearn
An assessment of Evans' unified field theory IIEvans developed a classical unified field theory of gravitation and electromagnetism on the background of a spacetime obeying a Riemann-Cartan geometry. In an accompanying paper I, we analyzed this…Friedrich W. Hehl, Yuri N. Obukhov·Mar 10, 2007SaveLearn
From E=mc2 to the Lorentz transformations via the law of addition of relativistic velocitiesIn this paper we show how to get the Lorentz transformations from E=mc2, the laws of conservation of energy and momentum, and the special relativity principle. To this end we first deduce the law of…C. Criado, N. Alamo·Mar 9, 2007SaveLearn
About the Constant of Motion, Lagrangian and Hamiltonian of the Gravitational Attraction of Two Bodies with Variable Mass (Gylden-Meshcherskii problem)The Lagrangian, the Hamiltonian and the constant of motion of the gravitational attraction of two bodies when one of them has variable mass is considered. This is done by choosing the reference…G. Lopez, E. M. Juarez·Mar 6, 2007SaveLearn
The Relative Angle Distribution Function in the Langevin Theory of Dilute DipolesThe Langevin theory of the polarization of a dilute collection of dipoles by an external field is often included in introductory solid state physics and physical chemistry curricula. The average…Robert D. Nielsen·Mar 5, 2007SaveLearn
Omega and the time evolution of the N-body problemThe series solution of the behavior of a finite number of physical bodies and Chaitin's Omega number share quasi-algorithmic expressions; yet both lack a computable radius of convergence.Karl Svozil·Mar 3, 2007SaveLearn
The geometrical nature and some properties of the capacitance coefficients based on Laplace's EquationThe fact that the capacitance coefficients for a set of conductors are geometrical factors is derived in most electricity and magnetism textbooks. We present an alternative derivation based on…William J. Herrera, Rodolfo A. Diaz·Feb 28, 2007SaveLearn
Comment on 'Helmholtz theorem and the v-gauge in the problem of superluminal and instantaneous signals in classical electrodynamics,' by Chubykalo et al [Found. of Phys. Lett, 19, 37-46 (2006)]Fundamental errors in the Chubykalo et al paper [Found. of Phys. Lett, 19, 37-46 (2006)] are highlighted. Contrary to their claim that "... the irrotational component of the electric field has a…Jose A. Heras·Feb 24, 2007SaveLearn
How potentials in different gauges yield the same retarded electric and magnetic fieldsThis paper presents a simple and systematic method to show how the potentials in the Lorentz, Coulomb, Kirchhoff, velocity and temporal gauges yield the same retarded electric and magnetic fields.…Jose A. Heras·Feb 24, 2007SaveLearn
Scaling of Huygens-front speedup in weakly random mediaFront propagation described by Huygens' principle is a fundamental mechanism of spatial spreading of a property or an effect, occurring in optics, acoustics, ecology and combustion. If the local…Jackson R. Mayo, Alan R. Kerstein·Feb 23, 2007SaveLearn
Theory and Applications of Infinitesimal Dipole Models for Computational ElectromagneticsThe recently introduced quantum particle swarm optimization (QPSO) algorithm is employed to find infinitesimal dipole models (IDM) for antennas with known near-fields (measured or computed). The IDM…Said M. Mikki, Ahmed A. Kishk·Feb 23, 2007SaveLearn
Bandwidth control of forbidden transmission gaps in compound structures with subwavelength slitsPhase resonances in transmission compound structures with subwavelength slits produce sharp dips in the transmission response. For all equal slits, the wavelengths of these sharp transmission minima…Diana C. Skigin, Hung Loui, Zoya Popovic et al.·Feb 23, 2007SaveLearn
Comparison of two models of a Double Inlet Miniature Pulse Tube Refrigerator - Part B : Electrical AnalogyThe design of a Double Inlet Pulse Tube Refrigerator is investigated by means of an analogy with an electric circuit. The results obtained with the electric scheme are compared with both those of the…Yannick Bailly, Philippe Nika·Feb 16, 2007SaveLearn
A class of vector identities relevant to the representation of the electric current densityA rigorous mathematical proof is given of a class of vector identities that provide a way to separate an arbitrary vector field (over a linear space) into the sum of a radial (i.e., pointing toward…M. Bornatici, O. Maj·Feb 15, 2007SaveLearn
Comment on "Preacceleration without radiation: The nonexistence of preradiation phenomenon," by J.A. Heras [Am. J. Phys. 74, 1025 (2006)]It is argued that a recent claim that there is no radiation in the preacceleration part of a non-runaway solution of the Abraham--Lorentz equation is incorrect.V. Hnizdo·Feb 14, 2007SaveLearn
An easy reading of modern ether-drift experimentsModern ether-drift experiments look for a preferred reference frame searching for modulations of the beat note of two optical resonators that might be induced by the Earth's rotation. We present…M. Consoli, E. Costanzo·Feb 14, 2007SaveLearn
Sivashinsky equation in a rectangular domainThe (Michelson) Sivashinsky equation of premixed flames is studied in a rectangular domain in two dimensions. A huge number of 2D stationary solutions are trivially obtained by addition of two 1D…Bruno Denet·Feb 13, 2007SaveLearn