# Physics:The Principles of Quantum Mechanics

* The Principles of Quantum Mechanics* is an influential monograph on quantum mechanics written by Paul Dirac and first published by Oxford University Press in 1930.

^{[1]}Dirac gives an account of quantum mechanics by "demonstrating how to construct a completely new theoretical framework from scratch"; "problems were tackled top-down, by working on the great principles, with the details left to look after themselves".

^{[2]}It leaves classical physics behind after the first chapter, presenting the subject with a logical structure. Its 82 sections contain 785 equations with no diagrams.

^{[2]}

Dirac is credited with developing the subject "particularly in Cambridge and Göttingen between 1925–1927" (Farmelo).^{[2]}

## Contents

## History

The first and second editions of the book were published in 1930 and 1935.^{[3]}

In 1947 the third edition of the book was published, in which the chapter on quantum electrodynamics was rewritten particularly with the inclusion of electron-positron creation.^{[3]}

In the fourth edition, 1958, the same chapter was revised, adding new sections on interpretation and applications. Later a revised fourth edition appeared in 1967.^{[3]}

Beginning with the third edition (1947), the mathematical descriptions of quantum states and operators were changed to use the Bra–ket notation, introduced in 1939 and largely developed by Dirac himself ^{[4]}

## Contents

- The principle of superposition
- Dynamical variables and observables
- Representations
- The quantum conditions
- The equations of motion
- Elementary applications
- Perturbation theory
- Collision problems
- Systems containing several similar particles
- Theory of radiation
- Relativistic theory of the electron
- Quantum electrodynamics

## See also

*The Evolution of Physics*(Einstein)*The Feynman Lectures on Physics*(Feynman)*The Physical Principles of the Quantum Theory*(Heisenberg)

## References

- ↑ "Paul A.M. Dirac – Biography". The Nobel Prize in Physics 1933. https://www.nobelprize.org/nobel_prizes/physics/laureates/1933/dirac-bio.html. Retrieved September 26, 2011. "Dirac's publications include ... The Principles of Quantum Mechanics (1930; 3rd ed. 1947)."
- ↑
^{2.0}^{2.1}^{2.2}Farmelo, Graham (June 2, 1995). "Speaking Volumes: The Principles of Quantum Mechanics" (Book review).*Times Higher Education Supplement*: 20. http://www.timeshighereducation.co.uk/story.asp?sectioncode=26&storycode=162404. Retrieved 2011-09-26. - ↑
^{3.0}^{3.1}^{3.2}Dalitz, R. H. (1995).*The Collected Works of P. A. M. Dirac: Volume 1: 1924–1948*. Cambridge University Press. pp. 453–454. ISBN 9780521362313. https://books.google.com/books?id=GBEdMdNWFJIC&pg=453#v=onepage&q&f=false. - ↑ PAM Dirac (1939). "A new notation for quantum mechanics".
*Mathematical Proceedings of the Cambridge Philosophical Society***35**(3): 416–418. doi:10.1017/S0305004100021162. Bibcode: 1939PCPS...35..416D.

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