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.

scholarly journals Test corpuscles in general relativity

1937 ◽  
Vol 5 (2) ◽  
pp. 63-81 ◽  
Author(s):  
H. P. Robertson
Keyword(s):  
World Line ◽  
Point Of View ◽  
Theoretical Physics ◽  
Finite Limit ◽  
Theory Of Relativity ◽  
The World ◽  
Electromagnetic Field Strength ◽  
Physical Attributes ◽  
Original Field ◽  
Extended Field

In the general theory of relativity, as in many other branches of theoretical physics, the material and energetical content of spacetime is considered, in the first instance, as an extended field, which is specified by means of field quantities (energy-momentum-stress tensor, charge-current density, electromagnetic field strength). From this point of view corpuscles (material particles, photons) are constructs obtained by first considering the field quantities as nonvanishing only within certain world tubes, and then passing by limiting processes to the idealisation in which these world tubes are shrunk into world lines. More precisely, this passage to the corpuscular description may be thought of as accomplished by replacing the original field by successive members of a sequence of field distributions, satisfying the same field laws, which cluster more and more in the neighbourhood of the world lines, and for which in some significant sense the total measure approaches a finite limit. Each such world line, together with the limiting measures of those portions of the field quantities associated therewith, is then a corpuscle; the form of the world line determines the motion of the corpuscle, and the associated “corpuscular quantities” its physical attributes (mass or energy, momentum, charge).

An alternative to special relativity: How a flawed experiment and misunderstanding of the fundamental laws of physics diverted physicists from their logical path

2020 ◽  
Vol 33 (1) ◽  
pp. 79-84 ◽  
Author(s):  
Cyrus Master-Khodabakhsh
Keyword(s):  
High Speed ◽  
Theoretical Physics ◽  
Newtonian Mechanics ◽  
Theory Of Relativity ◽  
Mass Energy ◽  
Method Of Calculation ◽  
True Path ◽  
Null Result ◽  
Energy Equivalence ◽  
Important Branch

The purpose of this paper is to show how the result of an erroneous experiment and the lack of understanding of the basic laws of Newtonian mechanics and its application diverted the progress of an important branch of theoretical physics from its true path and led to the creation of the theory of relativity (SR). Every year, many new papers regarding this theory are published that show its many contradictions and anomalies. This paper shows why Einstein's theory of relativity is theoretically and fundamentally incorrect and why, despite its problems, the theory gives some empirical predictions. A more logical solution based on Newtonian mechanics and on experiments and observations plus the concept of ether, leading to the same results, is proposed. As an example, mass-energy equivalence <mml:math display="inline"> <mml:mi>E</mml:mi> <mml:mo>≅</mml:mo> <mml:mi>m</mml:mi> <mml:msup> <mml:mrow> <mml:mi>c</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> </mml:math> is derived to show that Newtonian mechanics is adequate in the domain of high-speed particles. The derivation in this paper is by a similar technique to what has been previously published by the same author but with a different method of calculation. The paper also shows that SR does not explain, as claimed by Einstein, the null result of the Michelson and Morley experiment, which is the basis for the theory. It explains why the error in the experiment is hidden and difficult to detect. It also gives more information about the three previously published papers by the same author and endeavors to give a more comprehensive explanation as to what went wrong in this branch of theoretical physics.

scholarly journals Supplement to the Theory of Relativity

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Xiaoliang Miao
Keyword(s):  
Energy Equation ◽  
Newtonian Mechanics ◽  
Theory Of Relativity ◽  
Mass Energy ◽  
Theoretical Results

The problem about "who is right in relativity and Newtonian mechanics" is analyzed and discussed, and the theoretical results described in this study are only used as reference. This study reveals that there is no contradiction between relativity and Newtonian mechanics, and the essence of the relativity lies in the mass energy equation. 

Memories of early days in solid state physics

1980 ◽  
Vol 371 (1744) ◽  
pp. 56-66 ◽  
Keyword(s):  
State Physics ◽  
Quantum Mechanics ◽  
Solid State ◽  
Nobel Prize ◽  
Niels Bohr ◽  
Theoretical Physics ◽  
Solid State Physics ◽  
Research Papers ◽  
Atomic Collisions

Mott, Sir Nevill. Born Leeds 1905. Studied theoretical physics under R. H. Fowler in Cambridge, in Copenhagen under Niels Bohr and in Gottingen. Professor of Theoretical Physics in Bristol 1933-54, and Cavendish Professor of Physics, Cambridge 1954-71. Nobel Prize for Physics 1977. Author of several books and research papers on application of quantum mechanics to atomic collisions and since 1933 on problems of solid state science

Poincaré, Jules Henri (1854–1912)

2018 ◽  
Author(s):  
David J. Stump
Keyword(s):  
Philosophy Of Science ◽  
English Language ◽  
Philosophy Of Mathematics ◽  
Turn Of The Century ◽  
Theoretical Physics ◽  
Strong Impact ◽  
Theory Of Relativity ◽  
Language Philosophy ◽  
New Developments ◽  
Non Euclidean Geometry

Although primarily a mathematician, Henri Poincaré wrote and lectured extensively on astronomy, theoretical physics, philosophy of science and philosophy of mathematics at the turn of the century. In philosophy, Poincaré is famous for the conventionalist thesis that we may choose either Euclidean or non-Euclidean geometry in physics, claiming that space is neither Euclidean nor non-Euclidean and that geometry is neither true nor false. However, Poincaré’s conventionalism was not global, as some have claimed. Poincaré held that only geometry and perhaps a few principles of mechanics are conventional, and argued that science does discover truth, despite a conventional element. Poincaré followed new developments in mathematics and physics closely and was involved in discussion of the foundations of mathematics and in the development of the theory of relativity. He was an important transitional figure in both of these areas, sometimes seeming ahead of his time and sometimes seeming very traditional. Perhaps because of the breadth of his views or because of the way in which philosophers focused on issues or small pieces of his work rather than on accurate history, interpretations of Poincaré vary greatly. Frequently cited by the logical positivists as a precursor, and widely discussed in the philosophy of science and the philosophy of mathematics, Poincaré’s writings have had a strong impact on English-language philosophy.

Langevin's influence on relativity theories

2020 ◽  
Vol 33 (4) ◽  
pp. 380-386
Author(s):  
Douglas A. Staley
Keyword(s):  
Thought Experiment ◽  
Relativity Theory ◽  
Theoretical Physics ◽  
Theory Of Relativity ◽  
Speed Test ◽  
Starting Position ◽  
The Past ◽  
Eclipse Observations ◽  
Stop Watch ◽  
Light Beams

A century ago, Paul Langevin [C. R. 173, 831 (1921)], through his influence, convinced the scientific community that Einstein's theories of relativity were correct and could explain the Sagnac effect. A simple note in Comptes Rendus was all it took to silence many prominent skeptical scientists. The relativity skeptics had pointed to Sagnac's experiment [C. R. 157, 1410 (1913)] with the interference of counter rotating light beams as proof that the speed of light was not the same in both directions, contrary to the key postulate in Einstein's theory. Langevin showed that the result was also explained by relativity. The rest is history, and relativity has remained a center piece of theoretical physics ever since. Langevin had been captivated by solar eclipse observations of a shifted star pattern near the sun as reported by Eddington [Report on the Relativity Theory of Gravitation (Fleetway Press, Ltd., London, 1920)]. This was taken as proof positive for Einstein's General Theory of Relativity. The case of a light beam split into two beams, which propagate in opposite directions around a circuit, has an analog in a simple thought experiment—a speed test for runners. Two runners can be timed on a running track with the runners going around the track in opposite directions. Two stop watches will display the time for each runner's return to the starting position. The arithmetic difference in time shown on each stop watch will provide the differences in speed between the two runners. If the two speeds are the same, the time difference will be zero. It would not make any sense for one of the stop watches to measure a negative time, that is, time moving into the past. In fact, the idea is absurd! However, Langevin did just that, assigned the time for light to travel in one direction as positive while the time for the light to traverse in the opposite direction as negative, moving into the past! By so doing, Langevin reproduced Sagnac's expression and declared that relativity explains Sagnac's experiment. Langevin was wrong!

The interaction representation in the quantum theory of fields

1950 ◽  
Vol 201 (1065) ◽  
pp. 284-296 ◽  
Keyword(s):  
Quantum Theory ◽  
Schrödinger Equation ◽  
Schrodinger Equation ◽  
Unitary Transformation ◽  
Present Theory ◽  
Point Of View ◽  
Field Equations ◽  
Generalized Schrödinger Equation ◽  
Invariant Interaction ◽  
Theory Of Fields

The interaction representation has recently been introduced into the quantum theory of fields by Tomonaga and Schwinger. Applications of the theory to interacting meson-photon fields have led to apparent difficulties in determining invariant interaction Hamiltonians. Another troublesome feature is the necessity of verifying the integrability conditions of the so-called generalized Schrödinger equation. In the present paper the theory of the interaction representation is presented from a different point of view. It is shown that if two field operators with the same transformation character satisfy two different field equations, there is a unique unitary transformation connecting the field variables on any space-like surface given such a correspondence on one given space-like surface. A differential equation for determining this unique unitary transformation is found which is the analogue of Tomonaga’s generalized Schrödinger equation. This gives directly and simply an invariant interaction Hamiltonian and renders unnecessary the explicit verification of the integrability of the Schrödinger equation, since this is known to have a unique solution. To illustrate the simplification introduced by the present theory, the interaction Hamiltonian for the interacting scalar meson-photon fields is calculated. The result is the same as that obtained by Kanesawa & Tomonaga, but it is obtained by a straightforward calculation without the need to add terms to make the Hamiltonian an invariant.

scholarly journals Relativistic Effects in Reference Frames

1980 ◽  
Vol 56 ◽  
pp. 43-58 ◽  
Author(s):  
H. Moritz
Keyword(s):  
Gravitational Constant ◽  
Reference Frames ◽  
Relativistic Effects ◽  
Point Of View ◽  
Field Theories ◽  
Reference Systems ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
The Impact ◽  
Inertial Systems

AbstractThe impact of relativistic theories of space, time and gravitation on the problem of reference systems is reviewed.First, the concept of inertial systems is discussed from the point of view of the special and the general theory of relativity. Then, relativistic corrections of Doppler, laser and VLBI, and similar effects are reviewed; they are usually on the order of 10-8. Finally, the problem of a possible variation of the gravitational constant G (on the order of 10-11/year) is outlined; such a variation does not occur in special and general relativity, but is implied by certain generalized field theories which are less commonly accepted.

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