## Principles of Physics: From Quantum Field Theory to Classical Mechanics.

During the 20th century, physics experienced a rapid expansion. A general theoretical physics curriculum now consists of a collection of separate courses labeled as classical mechanics, electrodynamics, quantum mechanics, statistical mechanics, quantum field theory, general relativity, etc., with each course taught in a different book. I consider there is a need to write a book which is compact and merge these courses into one single unified course. This book is an attempt to realize this aim. In writing this book, I focus on two purposes. (1) Historically, physics is established from classical mechanics to quantum mechanics, from quantum mechanics to quantum field theory, from thermodynamics to statistical mechanics, and from Newtonian gravity to general relativity. However, a more logical subsequent presentation is from quantum field theory to classical mechanics, and from the physics principles on the microscopic scale to physics on the macroscopic scale. In this book, I try to achieve this by elucidating the physics from quantum field theory to classical mechanics from a set of common basic principles in a unified way.

## Principles of Physics: From Quantum Field Theory to Classical Mechanics pdf.

(2) Physics is considered as an experimental science. This view, however, is being changed. In the history of physics, there are two epic heroes: Newton and Einstein. They represent two epochs in physics. In the Newtonian epoch, physical laws are deduced from experimental observations. People are amazed that the observed physical laws can be described accurately by mathematical equations. At the same time, it is reasonable to ask why nature should obey the physical laws described by the mathematical equations. After wondering how accurately nature obeys the gravitational law that the gravitation force is proportional to the inverse square of the distance, one would ask why it is not found in other ways. Einstein creates a new epoch by deducing physical laws not merely from experiments but also from principles such as simplicity, symmetry and other understandable credos. From the view of Einstein, physical laws should be natural and simple. It is my belief that all physics laws should be understandable.

## PDF Free Download | Principles of Physics: From Quantum Field Theory to Classical Mechanics.

In this book, I endeavor to establish the physical formalisms based on basic principles that are as simple and understandable as possible. The book covers all the disciplines of fundamental physics, including quantum field theory, quantum mechanics, statistical mechanics, thermodynamics, general relativity, electromagnetic field, and classical mechanics. Instead of the traditional pedagogic way, the subjects and formalisms are arranged in a logical-sequential way, i.e., all the formulas are derived from the formulas before them. The formalisms are also kept self-contained, i.e., the derivations of all the physical formulas which appear in this book can be found in the same book. Most of the required mathematical tools are also given in the appendices. Although this book covers all the disciplines of fundamental physics, the book is compact and has only about 400 pages because the contents are concise and can be treated as an integrated entity. In this book, the main emphasis is the basic formalisms of physics. The topics on applications and approximation methods are kept to a minimum and are selected based on their generality and importance. Still, it was not easy to do it when some important topics had to be omitted. Since it is impossible to provide an exhaustive bibliography, I list only the related textbooks and monographs that I am familiar with. I apologize to the authors whose books have not been included unintentionally. This book may be used as an advanced textbook by graduate students. It is also suitable for physicists who wish to have an overview of fundamental physics.

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