Inhalt

Table of Contents

"Handbook of Contemporary Physics"

INTRODUCTION

INTERNATIONAL SYSTEM

PREFIXES

PHYSICAL CONSTANTS

NABLA OPERATOR

OUTLINE OF TENSORIAL CALCULATION

I | THE THEORY OF SPECIAL RELATIVITY

II | ELECTROMAGNETISM

III | THE PROBLEMS OF CLASSICAL PHYSICS

IV | QUANTUM MECHANICS

v | THE QUANTUM FIELD THEORY

VI | NUCLEAR PHYSICS, PARTICLE PHYSICS AND UNIFICATIONS

VII | THE THEORY OF GENERAL RELATIVITY AND ASTROPHYSICS

APPENDIX 1 | PLASMA PHYSICS

APPENDIX 2 | PHYSICS OF SOLID STATE AND SEMICONDUCTOR

APPENDIX 3 | THE THEORY OF GROUPS

APOSTILLA

"Handbook of Contemporary Physics"

"Handbook of Contemporary Physics"

SIMONE MALACRIDA

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This book deals concisely with all the theories of contemporary physics, from relativity (restricted and general) to quantum mechanics and quantum field theory, via nuclear and particle physics. In addition, the rudiments of plasma physics, solid state physics, semiconductor physics, and group theory are exposed.

The approach of this textbook is to deal directly with the mathematical formalism and to present the main equations of each theory, explaining their meaning and consequences as well as the problems left open.

The logical thread linking the different paragraphs is given by an overcoming of the old theories to meet the new requirements; meanwhile, two main directives in contemporary physics will be emphasized: the trend toward the unification of physical theories and the fundamental role of energy in the equations underlying each of them.

Simone Malacrida (1977)

Engineer and writer, has worked on research, finance, energy policy and industrial plants.

ANALYTICAL INDEX

INTRODUCTION

INTERNATIONAL SYSTEM

PREFIXES

PHYSICAL CONSTANTS

NABLA OPERATOR

OUTLINE OF TENSORIAL CALCULATION

I – THE SPECIAL RELATIVITY THEORY

II – ELECTROMAGNETISM

III – THE PROBLEMS OF CLASSICAL PHYSICS

IV – QUANTUM MECHANICS

V – THE QUANTUM FIELD THEORY

VI – NUCLEAR, PARTICLE PHYSICS AND UNIFICATIONS

VII – THE THEORY OF GENERAL RELATIVITY AND ASTROPHYSICS

APPENDIX 1 – PLASMA PHYSICS

APPENDIX 2 – PHYSICS OF THE SOLID STATE AND OF SEMICONDUCTOR

APPENDIX 3 – THE THEORYOF GROUPS

APOSTILLA

INTRODUCTION

INTRODUCTION

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Telling contemporary physics, and the history of this science, talking about what happened in the last 150 years is now quite frequent, especially if we consider the fields of application of relativity, electromagnetism, quantum mechanics and nuclear physics.

There are numerous popular writings, especially if they refer to a single sector mentioned above and there are, in addition, entire libraries of specialized texts at the university level and well beyond.

Usually, these two antithetical and complementary typologies have in common the characteristic of a certain length of writings. Explaining at a popular level or stating theories, complete with equations and consequences, are exercises that require a large number of words and pages.

This short manual, on the other hand, has a typical terseness due to the extreme synthesis in the exposition of some concepts and some effects.

Totally informative speeches will not be addressed, nor will all the necessary mathematical passages or scientific prerequisites be exposed to fully understand these theories. Nevertheless, all the main equations of this century and a half will be stated and explained, moving from one theory to another.

In addition, we will not follow a purely chronological order, but rather a logical one, starting with a year considered fundamental, 1905, and then going back before continuing along the course of the twentieth century. Even later, we will leave the exposition of general relativity at the end, anticipating instead theories that were enunciated decades later.

This logical order is part of a personal vision of the author (and it could not be otherwise), but it will certainly be of help in understanding along which lines contemporary physical knowledge has progressed.

The seven paragraphs of this manual are somewhat independent of each other, each of them addressing a topic of its own. It is true that there is a logical thread that links all the paragraphs and that constitutes the backbone of the manual, as well as the initial idea from which it sprang. Precisely by following this logical thread you will see all those parallels and all those innovations, very often unknown even to insiders.

For this reason, at least three topics are omitted from the main part of the book and presented in the appendix. The logical thread that has been chosen for the description of contemporary physics is independent of plasma physics, solid state physics and group theory. Nonetheless, these arguments are part of contemporary physics and that is why they will in any case be stated, albeit, as already mentioned, in the appendix.

In short, we can summarize the topics of the seven paragraphs that constitute the "heart" of this manual, as follows:

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1) The special theory of relativity

2) Electromagnetism and Maxwell's equations

3) The problems of classical physics

4) Quantum mechanics and the reconciliation with special relativity

5) The second quantization and the quantum field theory

6) Nuclear interactions, particle physics and the unification of forces

7) General relativity and astrophysical consequences

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As can be seen from this succinct list of topics, each paragraph by itself would be the subject of an entire book, and for each of these areas of physics, there are complete university courses. It is therefore obvious that there can be no completeness in the description of so many phenomena in so few pages.

This manual certainly does not have such an unrealistic claim. In a much simpler way, a logical scheme is proposed which tends to link a series of disparate physical theories in a single discourse as if to paint a common picture of knowledge that moves along precise directions.

One of these directions is the tendency towards unification, i.e. the pooling of phenomena and theories which, at first sight, seem disconnected but which science tells us are, decade after decade, increasingly interconnected like faces of the same die.

Another very common feature is the fundamental role that energy has in each of these theories. Energetic equations can be easily formulated which are then the basis of the theoretical and experimental assumptions.

We will have the certainty of this both with special relativity, through Einstein's equation placed at the beginning of the manual, and with quantum mechanics which took its impetus from Planck's equation for quantized energy up to the equation (also energy) by Schrodinger and with general relativity in which the tensor energy occupies a prominent place.

A third peculiarity that will be highlighted is the continuous overcoming of previous problems. As we will see, many theories were born to respond to problems, both experimental and theoretical, which cannot be explained by what was discovered by science at the time. Once these new theories were structured, it was found that the previous problems were easily solved, while others arose.

This characteristic is therefore part of an eternal race towards a better description of what surrounds us and a better understanding of all existing phenomena, in the wake of a derivation from the myth of Ulysses, which embodies man's eternal propensity to knowledge.

These major directives will also highlight a fundamental certainty. Current theories, those considered the most general of all and experimentally verified, are neither complete, nor exhaustive, nor totally correct.

The quantum field theory, which includes both the generalization of quantum mechanics and the reconciliation with special relativity and the explanation of nuclear interactions (at least of the weak one) has problems and limitations such that some physical phenomena do not agree with it. The same can be said of the general theory of relativity.

Basically, these two theories, failing to explain the totality of phenomena, are not as general as we think; most likely they are approximations of an even larger theory. This assumption is also based on the fact that neither of the two theories mentioned contemplates the results of the other within its own forecasts and that there are difficulties, for now insurmountable, to reconcile the two visions in a single overriding logical concept.

The soul of the paper coincides with the idea behind this manual, namely that by following a particular logical trend between energy equations and attempts at unification, a macro-path in the history of contemporary physics can be outlined to understand where we are going to end up in this twenty-first century.

In conclusion, after the necessary appendices to complete the picture of contemporary physics, there will also be room for even more general questions about the very meaning of nature, energy, science and the mathematical language adopted.