scholarly journals Nonlinear gravitational self-force: Second-order equation of motion

2017 ◽  
Vol 95 (10) ◽  
Author(s):  
Adam Pound
Keyword(s):  
Equation Of Motion ◽  
Order Equation ◽  
Second Order ◽  
Self Force

scholarly journals Second-order equation of motion for electromagnetic radiation back-reaction

2017 ◽  
Vol 32 (27) ◽  
pp. 1750147
Author(s):  
T. Matolcsi ◽  
T. Fülöp ◽  
M. Weiner
Keyword(s):  
Dirac Equation ◽  
Electromagnetic Radiation ◽  
External Force ◽  
Equation Of Motion ◽  
Order Equation ◽  
Second Order ◽  
The Self ◽  
Back Reaction ◽  
Relativistic Regime ◽  
Self Force

We take the viewpoint that the physically acceptable solutions of the Lorentz–Dirac equation for radiation back-reaction are actually determined by a second-order equation of motion, the self-force being given as a function of spacetime location and velocity. We propose three different methods to obtain this self-force function. For two example systems, we determine the second-order equation of motion exactly in the non-relativistic regime via each of these three methods, leading to the same result. We reveal that, for both systems considered, back-reaction induces a damping proportional to velocity and, in addition, it decreases the effect of the external force.

scholarly journals Non-Linear Neutral Differential Equations with Damping: Oscillation of Solutions

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 285
Author(s):  
Saad Althobati ◽  
Jehad Alzabut ◽  
Omar Bazighifan
Keyword(s):  
Differential Equations ◽  
Oscillatory Behavior ◽  
Order Equation ◽  
Second Order ◽  
Riccati Technique ◽  
Neutral Equations ◽  
Neutral Differential Equations ◽  
Main Equation ◽  
Non Linear ◽  
Even Order

The oscillation of non-linear neutral equations contributes to many applications, such as torsional oscillations, which have been observed during earthquakes. These oscillations are generally caused by the asymmetry of the structures. The objective of this work is to establish new oscillation criteria for a class of nonlinear even-order differential equations with damping. We employ different approach based on using Riccati technique to reduce the main equation into a second order equation and then comparing with a second order equation whose oscillatory behavior is known. The new conditions complement several results in the literature. Furthermore, examining the validity of the proposed criteria has been demonstrated via particular examples.

scholarly journals A relativistic basis of the quantum theory.—II

1934 ◽  
Vol 145 (855) ◽  
pp. 645-656 ◽  
Keyword(s):  
Quantum Mechanics ◽  
Wave Equation ◽  
Quantum Theory ◽  
General Expression ◽  
Matrix Equation ◽  
Covariant Derivative ◽  
Riemannian Geometry ◽  
Order Equation ◽  
Second Order ◽  
Space Curvature

The paper is a continuation of the last paper communicated to these 'Proceedings.' In that paper, which we shall refer to as the first paper, a more general expression for space curvature was obtained than that which occurs in Riemannian geometry, by a modification of the Riemannian covariant derivative and by the use of a fifth co-ordinate. By means of a particular substitution (∆ μσ σ = 1/ψ ∂ψ/∂x μ ) it was shown that this curvature takes the form of the second order equation of quantum mechanics. It is not a matrix equation, however but one which has the character of the wave equation as it occurred in the earlier form of the quantum theory. But it contains additional terms, all of which can be readily accounted for in physics, expect on which suggested an identification with energy of the spin.

Tensor Hypercontraction Equation-of-Motion Second-Order Approximate Coupled Cluster: Electronic Excitation Energies in O(N4) Time

2013 ◽  
Vol 117 (42) ◽  
pp. 12972-12978 ◽  
Author(s):  
Edward G. Hohenstein ◽  
Sara I. L. Kokkila ◽  
Robert M. Parrish ◽  
Todd J. Martínez
Keyword(s):  
Electronic Excitation ◽  
Equation Of Motion ◽  
Second Order ◽  
Coupled Cluster ◽  
Excitation Energies

On the Vibration of a Rotating Disk

1972 ◽  
Vol 39 (4) ◽  
pp. 1143-1144 ◽  
Author(s):  
S. Barasch ◽  
Y. Chen
Keyword(s):  
Approximate Calculation ◽  
Initial Conditions ◽  
Rotating Disk ◽  
Equation Of Motion ◽  
Outer Radius ◽  
Order Equation ◽  
System Of Differential Equations ◽  
Fourth Order Equation ◽  
First Order ◽  
Inner Radius

The equation of motion of a rotating disk, clamped at the inner radius and free at the outer radius, is solved by reducing the fourth-order equation of motion to a set of four first-order equations subject to arbitrary initial conditions. A modified Adams’ method is used to numerically integrate the system of differential equations. Results show that Lamb-Southwell’s approximate calculation of the frequency is justified.

Convergence behavior of popular schemes in case of calculating on adaptive grids problems with layers

2020 ◽  
pp. 66-79
Author(s):  
Владимир Дмитриевич Лисейкин ◽  
Виктор Иванович Паасонен
Keyword(s):  
Numerical Experiments ◽  
Order Equation ◽  
Second Order ◽  
Adaptive Grids ◽  
Coordinate Transformations ◽  
Diagonal Dominance ◽  
Counter Flow ◽  
Solution Quality ◽  
Uniform Grids ◽  
New Variables

Проведено сравнение качества решений модельного уравнения второго порядка с малым параметром, полученных по трем различным разностным схемам на специальных адаптивных сетках, явно задаваемых координатным преобразованием, а также на равномерных сетках в новых переменных, соответствующих этому преобразованию. Исследуются схемы второго порядка точности с диагональным преобладанием и без него и простейшая противопотоковая схема. На основе оценок погрешностей сделаны прогнозы относительно свойств решений, подтвержденные анализом и численными экспериментами. Показано, что схема второго порядка аппроксимации с диагональным преобладанием сходится равномерно по малому параметру со вторым порядком лишь в частном случае, когда коэффициент при старшей производной мал только в слое; если же он мал также и вне слоя, порядок сходимости первый. Установлено также, что схема без диагонального преобладания имеет существенно более качественные решения без осцилляций в новых переменных на равномерной сетке, чем в соответствующих им исходных физических координатах. В противоположность ей схемы с диагональным преобладанием не чувствительны к выбору системы координат. The paper compares solution quality to some model second- order equation with a small parameter obtained through three different schemes both on special adaptive grids specified explicitly by coordinate transformations eliminating layers and on uniform grids in a new coordinate related to the transformations. The schemes up to second order in physical and transformation variables both with a diagonal and not diagonal dominance and the simplest counter-flow scheme are analyzed. Predictions of a solution behavior based on estimates of solution errors are described, which are confirmed by numerical experiments and proofs. It is established, in particular, that the scheme of the second order with a diagonal dominance converges uniformly if the coefficient before the second derivative is small at the points of the boundary layer only. It was also demonstrated for the schemes without a diagonal dominance, mach better solutions without oscillations are obtained on uniform grids in new variables than on corresponding adaptive grids in the original physical coordinates.

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