Tensor Calculus

1994 ◽  
pp. 242-259
Author(s):  
Václav Vilhelm
Keyword(s):  
Tensor Calculus

Tensor Calculus

1949 ◽  
Author(s):  
John Lighton Synge ◽  
Alfred Schild
Keyword(s):  
Tensor Calculus

On the stability of crystal lattices IX. Covariant theory of lattice deformations and the stability of some hexagonal lattices

1942 ◽  
Vol 38 (1) ◽  
pp. 82-99 ◽  
Author(s):  
M. Born
Keyword(s):  
Elastic Constants ◽  
Hexagonal Lattice ◽  
Covariant Theory ◽  
Tensor Calculus ◽  
Crystal Lattices ◽  
New Form ◽  
The Stability ◽  
Central Forces

The theory of lattice deformations is presented in a new form, using the tensor calculus. The case of central forces is worked out in detail, and the results are applied to some simple hexagonal lattices. It is shown that the Bravais hexagonal lattice is unstable but the close-packed hexagonal lattice stable. The elastic constants of this lattice are calculated.

The imaging properties of electron beams in arbitrary static electromagnetic fields

1952 ◽  
Vol 245 (894) ◽  
pp. 155-187 ◽  
Keyword(s):  
Variational Equation ◽  
Chromatic Aberration ◽  
Relativistic Correction ◽  
Zero Order ◽  
Second Order ◽  
Optical Systems ◽  
Characteristic Functions ◽  
Tensor Calculus ◽  
Paraxial Ray ◽  
Imaging Properties

Electron-optical systems with curved axes—such as mass spectrographs and certain beta-ray spectrometers—have long been in practical use, but there has been available no complete theory of the aberrations of such systems. It is the object of the present paper to construct such a theory and to demonstrate, by an example, its application to practical problems. An appropriate co-ordinate system is set up by means of a ray-axis together with its normal and binormal. The electric and magnetic fields are then investigated with the help of tensor calculus; the variational principle of electron optics is also put into tensor form. The integrand of the variational equation may be separated into a series of polynomials, one of which determines the paraxial imaging properties of the system and the rest of which determine the aberrations. The condition is established for which, upon an appropriate transformation, either of the paraxial ray equations contains only one off-axis co-ordinate. Subsequent investigations are restricted to systems, which are termed ‘orthogonal’, for which this condition is satisfied. It is shown that, in a certain sense, no orthogonal electron-optical system can be wholly divergent. The second-order aberration and the zero-order and paraxial chromatic aberrations are then investigated by the method of perturbation characteristic functions. All formulae are given in their relativistic forms but their non-relativistic forms are indicated; formulae are therefore given for the calculation of the zero-order and paraxial relativistic correction. It is indicated to what extent one forfeits control over the second-order aberration—and hence over the paraxial chromatic aberration also—by specifying that the paraxial behaviour of rays should be Gaussian. As an example, the imaging properties of a helical beam moving in the field of a pair of coaxial cylindrical electrodes are calculated. There is also an appendix which gives formulae for the effect upon aberrations of a change in the aperture position.

scholarly journals Magnetic deformation of super-Maxwell theory in supergravity

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Ignatios Antoniadis ◽  
Jean-Pierre Derendinger ◽  
Hongliang Jiang ◽  
Gabriele Tartaglino-Mazzucchelli
Keyword(s):  
Real Field ◽  
Necessary Condition ◽  
Tensor Calculus ◽  
Maxwell Theory ◽  
Abelian Gauge ◽  
Alternative Description ◽  
Minimal Supergravity ◽  
Global Supersymmetry ◽  
Nonlinear Deformations ◽  
Working Out

Abstract A necessary condition for partial breaking of $$ \mathcal{N} $$ N = 2 global supersymmetry is the presence of nonlinear deformations of the field transformations which cannot be generated by background values of auxiliary fields. This work studies the simplest of these deformations which already occurs in $$ \mathcal{N} $$ N = 1 global supersymmetry, and its coupling to supergravity. It can be viewed as an imaginary constant shift of the D-auxiliary real field of an abelian gauge multiplet. We show how this deformation describes the magnetic dual of a Fayet-Iliopoulos term, a result that remains valid in supergravity, using its new-minimal formulation. Local supersymmetry and the deformation induce a positive cosmological constant. Moreover, the deformed U(1) Maxwell theory coupled to supergravity describes upon elimination of the auxiliary fields the gauging of R-symmetry, realised by the Freedman model of 1976. To this end, we construct the chiral spinor multiplet in superconformal tensor calculus by working out explicitly its transformation rules and use it for an alternative description of the new-minimal supergravity coupled to a U(1) multiplet. We also discuss the deformed Maxwell theory in curved superspace.

Tensor Calculus

1955 ◽  
Vol 39 (327) ◽  
pp. 72
Author(s):  
G. J. Withrow ◽  
B. Spain
Keyword(s):  
Tensor Calculus

Covariant Physics

2021 ◽  
Author(s):  
Moataz H. Emam
Keyword(s):  
Point Of View ◽  
Theoretical Physics ◽  
Newtonian Mechanics ◽  
Theory Of Relativity ◽  
College Physics ◽  
Introductory Courses ◽  
Tensor Calculus ◽  
Research Papers ◽  
Intended Reader ◽  
Theory Of Fields

This book is an introduction to the modern methods of the general theory of relativity, tensor calculus, space time geometry, the classical theory of fields, and a variety of theoretical physics oriented topics rarely discussed at the level of the intended reader (mid-college physics major). It does so from the point of view of the so-called principle of covariance; a symmetry that underlies most of physics, including such familiar branches as Newtonian mechanics and electricity and magnetism. The book is written from a minimalist perspective, providing the reader with only the most basic of notions; just enough to be able to read, and hopefully comprehend, modern research papers on these subjects. In addition, it provides a (hopefully short) preparation for the student to be able to conduct research in a variety of topics in theoretical physics; with particular emphasis on physics in curved spacetime backgrounds. The hope is that students with a minimal mathematical background in calculus and only some introductory courses in physics may be able to study this book and benefit from it.

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