Reading Paul Dirac's "Principles of Quantum Mechanics"

Question

I have a similair question to the question here, but regarding a different book.

"Principles of Quantum Mechanics" is a 1930 work by British Nobel laureate Paul Dirac. The wikipedia article on this book states that there have been a couple of editions (with improvements and additions), the latest being the 4th edition, published in 1958 (6 years before the Feynman lectures were published). This is a long time ago and I'm wondering if parts of the book are outdated, and if so, which ones and why?

This post imported from StackExchange Physics at 2014-06-14 13:21 (UCT), posted by SE-user OmnipresentAbsence

Comments

Probably helpful (and possible dupe): physics.stackexchange.com/q/30115

This post imported from StackExchange Physics at 2014-06-14 13:21 (UCT), posted by SE-user Colin McFaul

---

That is helpful, but I don't think it's exactly a duplicate. It's not asking quite the same thing that this question is.

This post imported from StackExchange Physics at 2014-06-14 13:21 (UCT), posted by SE-user David Z

---

The last chapter on QED is somehow outdated, due to his aspect on renormalization. Others are fine to me (unless the notation is somehow less pretty than Sakurai's book).

This post imported from StackExchange Physics at 2014-06-14 13:21 (UCT), posted by SE-user user26143

Answer 1

Dirac did the last revision of that book in 1967, in the chapter of QED.

The book is 100% valid, nothing is outdated. You may only notice some slight difference of style with more modern books, in the absence of drawings and sometimes in the notation (most integration indices are not explicit, for instance). There aren't any exercises as well, but nevertheless it is a very good book, well structured and very clear.

Together with Sakurai's Modern Quantum Mechanics, it is the best book for mastering QM directly in the Dirac kets and bras notation.

This post imported from StackExchange Physics at 2014-06-14 13:21 (UCT), posted by SE-user Eduardo Guerras Valera

Comments

Thank you. Would you know of a good supplement to this book for someone who wants to learn QM (perhaps one which also has exercises)?

This post imported from StackExchange Physics at 2014-06-14 13:21 (UCT), posted by SE-user OmnipresentAbsence

---

@OmnipresentAbsence, It makes a huge different if you are learning alone in your free time, or if you are at a physics faculty. If you are alone, I think the best way to learn is by covering the whole material several times, in waves of increasing complexity, restricting yourself to a single source of information (a book, video lectures, notes, whatever) in each wave. Quantum Mechanics can be painful and confusing if you try to consult several books at a time before having achieved a certain level of knowledge maturity, because there are multiple ways of exposing the material...

This post imported from StackExchange Physics at 2014-06-14 13:21 (UCT), posted by SE-user Eduardo Guerras Valera

---

@OmnipresentAbsence, , and every author chooses his own pathway. What is your background? Are you a physics student conversant with Hamiltonian mechanics? Are you perhaps a software engineer that is interested in QM as a hobby? In the first case, you could stick to Sakurai' s Modern Quantum Mechanics (its flavour is somewhat similar to Dirac). In the second case, I would recommend first Leonard Susskind lectures on youtube ("Quantum Entanglements 1"), reproducing the examples, and thereafter, McMahon's Quantum Mechanics Demystified, with its solved exercises. I don't like Griffiths at all.

This post imported from StackExchange Physics at 2014-06-14 13:21 (UCT), posted by SE-user Eduardo Guerras Valera

---

I must admit I haven't even started with Hamiltonian mechanics, but I will very soon (this week actually). I'm learning in my free time, I still have quite some things to do before (strengthening my calculus mainly), but it's never too soon to choose a good book, right?

This post imported from StackExchange Physics at 2014-06-14 13:21 (UCT), posted by SE-user OmnipresentAbsence

---

@OmnipresentAbsence Then, if you are at the faculty now, it much depends on your future QM professor and what books (s)he will follow. My QM professor was horrible, and so I learnt by myself with a very old small book I found in the library, that helped me a lot (P.T. Matthews, but it is not sold anymore). But it is necessarily not your case, perhaps you are going to have a good professor.

This post imported from StackExchange Physics at 2014-06-14 13:21 (UCT), posted by SE-user Eduardo Guerras Valera

Answer 2

I can't recommend anything written by Dirac as an introduction to the concepts in Quantum Physics. The two most common textbooks for a beginner (which include exercises) are "Quantum Mechanics" by Alastair Rae. (most recent update 2008) and "Introduction to Quantum Mechanics" by David Griffith (Most recent update 2004).

Both books cover near identical material, but have different examples and different approaches.

From there, a good continuation point would be "Introduction to Elementary Particles" also by David Griffith.

Finally, after all that and you still want more, I'd recommend An "Introduction to Quantum Field Theory" by Michael Peskin and Daniel Schroeder, this book covers the same material that Dirac's book, but is considered a lot more approachable. If you somehow get through all this, you know more Quantum Physics than most Physics graduates. As a matter of fact, Peskin and Schroeder is reading material for people taking their Theoretical Physics PhD!

This post imported from StackExchange Physics at 2014-06-14 13:21 (UCT), posted by SE-user Matt Scott

Comments

Why would you not recommend anything by Dirac?

This post imported from StackExchange Physics at 2014-06-14 13:21 (UCT), posted by SE-user OmnipresentAbsence

---

@OmnipresentAbsence He is notoriously poor at explaining things to beginners. It's a simple matter of being a poor communicator. If you don't already have an advanced (and I mean really advanced) grasp of mathematics Dirac has nothing to offer you.

This post imported from StackExchange Physics at 2014-06-14 13:21 (UCT), posted by SE-user Matt Scott

---

Notoriously bad? This book was recommended to me by dozens of people!

This post imported from StackExchange Physics at 2014-06-14 13:21 (UCT), posted by SE-user OmnipresentAbsence

---

I don't know what to say about people recommending it to you, I assume that you're looking into books because you aren't familiar with QM and you want an introductory level book. Again I can only state that Dirac's material in general is not suitable for beginners due to his very high demands on what he assumes the reader already knows. Dirac is famous for his terrible communication skills, and Principles of Quantum mechanics is no exception. He was certainly an excellent physicist and mathematician but there have been hundreds of people who can explain his ideas better than him.

This post imported from StackExchange Physics at 2014-06-14 13:21 (UCT), posted by SE-user Matt Scott

---

@OmnipresentAbsence Old is gold. Dirac's been there in the battlefield and he's one of those who experienced the development of QM firsthand. Original is always better

This post imported from StackExchange Physics at 2014-06-14 13:21 (UCT), posted by SE-user Cheeku

---

@OmnipresentAbsence I agree, original is best. I can say that Dirac's Principals of QM was the first book on QM I ever read that made any sense to me.

This post imported from StackExchange Physics at 2014-06-14 13:21 (UCT), posted by SE-user ntropy

Answer 3

Dirac's book was once thought to be a very hard book to understand (and because of its yellow cover, was called “the yellow terror”, an shared by Norbert Wiener’s book “The Theory of the Fourier Integral”) but is actualy an extremely lucid account.

Its methodical treatment makes up for the lack of figures and pyrotechnics.

Be prepared to read it slowly - Dirac was famous for not wasting words - and rereading passages after reaching a deeper understanding.

This post imported from StackExchange Physics at 2014-06-14 13:21 (UCT), posted by SE-user user34263

Answer 4

The title of the book gives it away. It's the Principles of QM. i.e the actual mathematical structure of the theory presented in a bare-bones, dry-as-dust format. It even states on the cover that it's a monograph, intended as a reference work for researchers and advanced students of the subject.

It's very thorough and as concise as possible so that reading it really requires a reasonable grasp of the subject to begin with. That is also why it's actually quite a slim volume despite the depth of cover. I don't remember seeing a single figure or illustration in the entire book.

Besides all that, although physics may not have come a long way since it was published, teaching techniques certainly have. IMO It would be a cruel trick to offer a textbook of that period to a modern student.

This post imported from StackExchange Physics at 2014-06-14 13:21 (UCT), posted by SE-user Anthony

Comments

The question was if it's outdated.

This post imported from StackExchange Physics at 2014-06-14 13:21 (UCT), posted by SE-user jinawee

---

@jinawee well it is a useful answer because it clarifies that the content of the book is still valid but, in the answerer's opinion, it is outdated as far as teaching methods and ease of transfering knowledge currently goes.

This post imported from StackExchange Physics at 2014-06-14 13:21 (UCT), posted by SE-user anna v