Customer Reviews

Modern Quantum Mechanics (Revised Edition)

5 star:		(23)
4 star:		(10)
3 star:		(2)
2 star:		(3)
1 star:		(4)

 

 

The majority of undergraduate QM texts, e.g. Liboff, Bransden & Joachain, Cohen-Tannoudji, rely strongly upon the wave-interpretation of QM, Schrodinger's equation, and the semi-historical exposition style which invariably invokes the ultraviolet catastrophe. I feel that as an introduction to QM, this is fine. However, this semi-classical approach has the disadvantage that the reader/student has one foot firmly planted in classical thinking, and makes connections to QM only through the emergence of contradictory observations in classical physics. Maybe if you were learning quantum mechanics in 1908 this approach would be fine.

But in the 21st century, perhaps it would be better to start off with one foot planted firmly in the weird, axiomatic and algebraic land of QM first, and to make contact with classical observations later. This is the approach of Sakurai. A quote from Julian Schwinger appropriately summarizes this idea, that this is a "non-historical approach" that "goes to the heart of the quantum experience."

The book does such a good job of explaining fundamentals that I have found it enjoyable to read. Gaps in derivations are suitably placed such that the reader may attack them for exercise. However, they are not detrimental to the progression of ideas. Exercises are suitably difficult, and introduce new ideas that are related to ones in the chapter.

Sakurai was one of the smartest physicists of his generation, and it shows in this book. A characteristic of the physics writings of such greats as Einstein, Pauli, Heisenberg, and Dirac is that they make advanced physics theories seem so clear and transparent that one is always inclined to think, "of course, that's the way to do it." Sakurai's book comes across the same way, but there are plenty of good problems to bring you back down to Earth. Especially useful are the discussions of Feynman path integrals, the Aharonov-Bohm effect, the WKB approximation, Schwinger's treatment of angular momentum, and the Dyson series in perturbation theory.

As many reviewers have already pointed out, the Sakurai was completed after the death of its attributed author, and one can definitely see after chapter 3 that this is definitely where things drop off (the chapter on symmetries is convoluted and very mathematical, almost to a fault). The notation is often cumbersome; I have to say that out of the six or so quantum mechanics books I have read or own, this is the only one where you will see notation like <a'|x''''><x''''|a''>.

Aside from the fourth chapter (which is weak at best) and the cumbersome notation, this is one of the best textbooks for quantum mechanics out there. Chapter 1 is the best discussion of linear algebra in quantum mechanics I have ever seen, and it alone is worth about $40. Although sometimes a little scattershot, the third chapter, on angular momentum, is also the best introduction to the theory of angular momentum I have ever seen. The text does not baby you like some undergraduate texts (the Griffiths immediately comes to mind), and treats you like an actual physicist capable of working through some pretty complicated problems.

Perturbation theory is an almost purely mathematical tool with very little physical "intuition" to be had, and therefore these sections of the book are not bad.

As far as I can tell, with Baym out of the picture, the race for "standard" graduate school textbook on QM is a dead heat between the established Sakurai and the upstart Shankar, and both books have their ups and downs. The Shankar can be too long-winded at times, although it covers path integration in much greater depth than the Sakurai. However, the Sakurai's treatment of symmetry operations is much more in-depth than the Shankar's. As far as I am concerned, the only way to get the best of both worlds right now is to drop the cash and read both books. The Sakurai is probably a much better way to learn the subject, but there are a few holes in Sakurai that Shankar covers well, although with a verbose style and with very simple problems.

While teaching qm in the seventies and eighties I preferred Baym. A few years ago I decided on Sakurai and did not regret it. It's necessary to supplement the text with many derivations and details, but this book provides an excellent approach to qm in the spirit of Dirac, and provides a very good takeoff point for discussing the famous measurement problem (was there necessary to enlarge the discussion presented in Sakurai). I motivated the transition to qm by using Heisenberg's The Physical Principles of Quantum theory, where he explains how he was motivated in spirit by relativity theory to give up the idea of predictability of simultaneity of position and momentum. I ended the course by going to the literature and working through EPR and an introduction to quantum computation. A severe weakness: Sakurai assumes that the reader has learned elsewhere about the qm of the hydrogen atom!

I truly love this book. The sections that Sakurai wrote could not have been written better. He uses Dirac's notation from the beginning, which provides the reader with a much better understanding of what's going on than the usual wave mechanics intro. There are some weak points, however- mostly sections that were added after Sakurai died. The treatment of time-independent PT in chapter 5 is unnecessarily wordy and complicated. Chapter 6 on multiparticle states is fair to brief. I didn't think that the scattering sections in chapter 7 were very good, but I haven't seen it done well anywhere else either. Everything else, however, is wonderful.

This book is often a standard text for introductory graduate-level quantum mechanics, which is the only reason why people may give it praise. This book is not illuminating, nor does it serve as a good reference tool.

Sakurai seems to have written in the hidden secret style. Where he skips steps and explanation, not because they are simple or obvious, but because he believes the reader should work all that out for himself. As such, it is terrible as reference as it is somewhat disorganized (maybe not his fault) and seemingly intentionally unclear for someone trying to learn.

This attitude is most reflected in the problems. They, except for a very few exceptions, are at a much greater level of difficulty than any explanation or example in the text. Some of these problems are insoluable with the tools presented in the chapters. And, most require reference to other works to gain strong exposition.

When I was first using this book, I would often suffer from not realizing when the notation suddenly changed, and what assumptions Sakurai was making. I found myself gaining much better insight from other works that I referenced.

I would suggest you only buy this book if you must for a class, and I ask instructors to do a little research and find a text that has a bit more focus on pedagogy. (Though I must confess, I do not know what would be focussed upon less. I feel the text is without focus, and entire pages of text are misleading pointless.)

Judging by the other reviews, it's clear that alot ofpeoplelike this book. I am not one of them. First of all, the greatmajorityof this book was written after Sakurai's death, and those who are familiar with his other works will surely notice that his trademark clarity of presentation is absent here. The notation used throughout this book is cumbersome; no student should be subjected to variables denoted with 4 primes, and primes on the primes, etc. The proofs are unclear and in some cases downright ugly; student's can easily take pride in redoing the proofs in half as much space as is taken in the book, while adding clarity at the same time. Sure, Sakurai's death was tragic, but to finish this book post mortem, and then put his name on this work seems to be an insult. Unfortunately, it is true that there are not many good QM books out there for the first semester physics grad student to chew on. Still, I don't think this book is even worth owning. Admittedly, I am in the minority when compared to the other reviewers, but I would recommend taking a good look at this book before deciding to waste your money. END

This book serves as a very good introduction to advanced quantum mechanics course. It contains standard contents and some new developements such as Bell's Inequality, Aharonov-Bohm effect etc. All of these are well presented. The book is concise but still contains enough details. Anyone having this book will love it!!

Sakurai's quantum mechanics textbook is the one with which I started understanding quantum mechanics. It is, however, not for beginners in the field. But if you are familiar with basic quantum concepts (wave-particle dualism, uncertainty principle, and maybe even some easy tunneling phenomena with wave functions and boundary conditions), you will certainly enjoy Sakurai's book.

The book starts with the presenation of spin-1/2 systems and the Stern-Gerlach experiment. Throughout the text, reference is made to this very compelling example of quantum systems. Oerators are related to symmetry transformations, and the text is really both straightforward and well structurized.

But then, the argument given by my fellow reviewer Doug Irving is quite correct - and that's why I can give only 4 stars for the book. Especially somewhere in the perturbation series the quality of the explanations and the argumentative clarity suddenly deteriorates. Finally, the scattering theory consists mainly only of formula with no further insight from helpful comments.

Nonetheless, in my opinion the first chapters are written very well and can thus be recommended to any graduate student in physics. This is also due to the fact, that the book focuses on the key issues of quantum mechanics and leaves out less important material. What is the use of a 2-volume 1000-page quantum mechanics book if the average student remembers at most 10% of it. These 10% are contained in "Modern Quantum Mechanics".

The book is good and very clear. If you want to learn QM to apply it to statistical mechanics, condensed matter or solid state physics, etc. this book will suffice. But if you intend to specialize in field theory or superstrings, for instance, I recommend you to study QM from Ballantine. Sakurai is pretty good but he presents QM as if it were a set of rules that cannot be changed. I think that's not very interesting for a future theoretical physicist. Besides, he omits certain mathematical details (such as the existence of a complete set of eigenvectors for self-adjoint operators even in the case of continuous spectra, in rigged Hilbert Space or under Von Newmann formalism). In one point Sakurai is really wrong: he says that the use of self-adjoint ops. is needed in order that its eigenvalues are real. That's incidental: self-adjointness is crucial not because the eigval are real but because its eigenvectors form a complete set.
One thing is certain: using Sakurai you'll learn how to solve problems and apply QM to numerous situations, but you'll miss the foundations of the theory.