Quantum Theory

Rating:
Summary: A superb book on quantum mechanics. Readable and rigorous.
Review: Bohm explains quantum mechanics at a level that gives great physical insight and understanding. It not only provides theory, but also gives detailed historical accounts of the development of the theory. A great text for undergraduates.

Rating:
Summary: A Crystal-Clear Gem of a Book-- Lucid and Insightful
Review: Don't let the original 1950's publication date fool you. This book is as relevant and important today as it was when it was first published.

In fact, Bohm's lucid, pointed three-page preface-- in which he outlines in simple English the three exact ways Quantum Mechanics differs from Classical Mechanics (which I had never seen done before and which few physics students ever really grasp)-- that ALONE is worth the price of this book.

Let me help you understand why, without reservation, I feel this book to be a masterpiece of clarity in exposition.

When I first learned Quantum Mechanics-- and, as I have come to learn, my experience was not atypical-- it was basically axiomatic: "Here are these mathematical techniques. If we do this and that and then that to this function, then we can predict certain things about experimental results." I found this a tremendously difficult-- not to mention frustrating-- way of learning things. Mathematically intense, but with little physical understanding.

I memorized the rules, and did OK in my courses, but what I really wanted to know was: WHY was I doing these things? Where did this stuff COME from? And, most importantly, what did this stuff MEAN?

I got bits and pieces-- only hints, really-- from several other textbooks. When I got to grad school, I was excited to finally learn what it all meant. Unfortunately, my grad course was more of the same type of calculation-- just calculating more difficult things! In fact, I had almost given up at really understanding what it all MEANT, and was ready to take my graduate Quantum professor's advice to "Just learn the techniques and use the stuff" when I came across David Bohm.

In a textbook that is more wordy than most novels-- and yet, in which not a single noun is extraneous or out of place-- Bohm takes us on a clear and exciting tour of WHERE Quantum Mechanics comes from, exactly HOW it developed from Classical Mechanics, exactly how it DIFFERS from Classical Mechanics, and, finally, what it all MEANS physically.

He does this by consistantly referring to experiment, by devloping mathematical techniques as necessary, and by discussing and explaining in clear prose what such concepts as the wave function actually MEAN.

It is difficult to overemphasize how comfortable one feels reading this book--- you feel that you are being guided with a firm yet gentle hand by one who truly understands what it means to truly EXPLAIN something. (For all the praise that is heaped on such texs as the Feynman Lectures and Landau and Lifshitz, they can't shake a stick at Bohm's abilities at lucidity in exposition.)

Finally, after developing the traditional calculational techniques, in the last sections of the book Bohm discusses such alternatives as the "hidden variable" theory in balanced yet intriguing ways, and leaves you wanting more.

If I am disappointed in anything, it would be only this:

Why didn't this Shakespeare of physics authors write more?

Rating:
Summary: A Crystal-Clear Gem of a Book-- Lucid and Insightful
Review: Don't let the original 1950's publication date fool you. This book is as relevant and important today as it was when it was first published.

In fact, Bohm's lucid, pointed three-page preface-- in which he outlines in simple English the three exact ways Quantum Mechanics differs from Classical Mechanics (which I had never seen done before and which few physics students ever really grasp)-- that ALONE is worth the price of this book.

Let me help you understand why, without reservation, I feel this book to be a masterpiece of clarity in exposition.

When I first learned Quantum Mechanics-- and, as I have come to learn, my experience was not atypical-- it was basically axiomatic: "Here are these mathematical techniques. If we do this and that and then that to this function, then we can predict certain things about experimental results." I found this a tremendously difficult-- not to mention frustrating-- way of learning things. Mathematically intense, but with little physical understanding.

I memorized the rules, and did OK in my courses, but what I really wanted to know was: WHY was I doing these things? Where did this stuff COME from? And, most importantly, what did this stuff MEAN?

I got bits and pieces-- only hints, really-- from several other textbooks. When I got to grad school, I was excited to finally learn what it all meant. Unfortunately, my grad course was more of the same type of calculation-- just calculating more difficult things! In fact, I had almost given up at really understanding what it all MEANT, and was ready to take my graduate Quantum professor's advice to "Just learn the techniques and use the stuff" when I came across David Bohm.

In a textbook that is more wordy than most novels-- and yet, in which not a single noun is extraneous or out of place-- Bohm takes us on a clear and exciting tour of WHERE Quantum Mechanics comes from, exactly HOW it developed from Classical Mechanics, exactly how it DIFFERS from Classical Mechanics, and, finally, what it all MEANS physically.

He does this by consistantly referring to experiment, by devloping mathematical techniques as necessary, and by discussing and explaining in clear prose what such concepts as the wave function actually MEAN.

It is difficult to overemphasize how comfortable one feels reading this book--- you feel that you are being guided with a firm yet gentle hand by one who truly understands what it means to truly EXPLAIN something. (For all the praise that is heaped on such texs as the Feynman Lectures and Landau and Lifshitz, they can't shake a stick at Bohm's abilities at lucidity in exposition.)

Finally, after developing the traditional calculational techniques, in the last sections of the book Bohm discusses such alternatives as the "hidden variable" theory in balanced yet intriguing ways, and leaves you wanting more.

If I am disappointed in anything, it would be only this:

Why didn't this Shakespeare of physics authors write more?

Rating:
Summary: Disappointed
Review: I bought the book because of the good reviews below and the low price. I was a little disappointed with Bohm's explanations and wordings of concepts that I already know. I think that it'd be difficult for someone to learn anything from this book unless (s)he is already familiar with quantum mechanics. Anyhow, the book is still a good buy considering it is at least 5 times cheaper than textbooks on quantum mech.

Rating:
Summary: I (think) I finally understand...
Review: The age of the book is what gives it a huge advantage to today's typical QT and QM textbook. Instead of presenting the concepts in the "status quo" of physics (usually just a ridiculously brief intro to why QT started, and then presenting Operators as things almost perfectly synonymous to classical concepts and continuing from there), this book really goes through the history of where all the math came from. Bohm is very careful about teaching you what parts of the math are just convenience tricks (like Operators) versus real necessities to QM. And also what parts are just based on just experiments. Unlike today, in the 1950's, QT and QM were still suspect theories, so students were taught of the known and possible holes (no pun intended :) in the theory. Bohm points these out throughout the whole book.

Rating:
Summary: Quantum mechanics without the Dirac Bracket
Review: The title page of this book lists Bohm as a professor emeritus at the University of London but this is actually a text developed at Princeton in the late 1940's. Not long after the book was written, Bohm had got himself in trouble for not revealing what left-wing activities he had got himself involved in with his mentor J.R. Oppenheimer. Princeton couldn't stand the political heat of having a suspected communist on its physics faculty and Bohm got booted out. He wandered off to Brazil and Israel before finally ending up in London. Ironically, Princeton had fired someone who had just written one of the greatest classics of the quantum mechanics literature. The book is outstanding for its extensive discussion of the philosophical foundations of quantum theory. Bohm at that time believed in the Copenhagen Interpretation of Niels Bohr. Only traditional mathematics, rather than the murky abstraction of the Dirac bracket, is used. Carefully selected problems are inserted into the text whenever important new material has been introduced. Although the book is a little dated, today's reader should still find the chapters on the WKB approximation, Heisenberg matrix mechanics, and perturbation theory edifying. In short, this is a book to be enjoyed.

Rating:
Summary: Philosophical-Technical
Review: This is a book for you to read again and again through your whole life. When you are an undergraduate, lots of good technical information are found in this volume regarding, for instance, wave packets or the hydrogen atom. As you get more experienced and, of course, if you have some interest in the philosophical issues raised by the subject, the book turns to be a reference again.

Rating:
Summary: Cheap, fair book which you can't treat too seriously
Review: This is a fair textbook of quantum mechanics, and it is very cheap. Well, I mean cheap as well as cheap. It does not contain too much mathematics. However, the words are usually good substitutes. The book covers the usual basic material of quantum mechanics based on the wavefunctions; the particle in the most usual potentials; perturbation theory; the concept of spin, and so forth.

However, I don't think that David Bohm was really among those who understood the meaning of quantum mechanics too well - and based on the other reviews, I think that the readers who claim that they finally understood quantum mechanics from this book have not really gotten the point either. Well, don't get me wrong: the book was written in 1950 and at that time, Bohm more or less believed the orthodox Copenhagen interpretation of quantum mechanics even though he had many more doubts about the important principles of QM than what would have been appropriate.

Nevertheless, David Bohm spends relatively too much time with his (rather unsuccessful) speculations about the "deeper", deterministic structure underlying quantum mechanics. David Bohm's second most well-known contribution to physics (after the Aharonov-Bohm effect) is his new version of the pilot wave theory, initiated by de Broglie in the late 1920s and used to change the interpretation of quantum mechanics.

His new interpretation is based on the idea that the wavefunction is a real wave, and moreover there also exists a classical particle with a well-defined position. These two objects classically interact in such a way that the probabilistic results of quantum mechanics can be reproduced in several simplest contexts.

However, this is not a correct idea for more convoluted systems; experimentally speaking, it contradicts special relativity (as required in relativistic quantum field theory), the existence of spin, and so forth. More generally, even without these advanced concepts in quantum mechanics, Bohm's idea goes against the spirit of quantum mechanics with its Hilbert spaces and different bases and operators on the same Hilbert space that are "equally important".

Bohm's prejudices about determinism and the special role of the position operator may have followed from his unfortunate, conventional technical approach to quantum mechanics that always starts with wavefunctions in the position representation - an approach chosen also in this book. This representation leads many readers to the wrong conclusion that the wavefunction is something like a real classical wave in space - much like the electromagnetic wave - and that the position has a special role among the observables. I say "observable" because Bohm tries to humiliate the concept of an operator.

I agree with others who say that we are not spending enough time by teaching the interpretational issues of quantum mechanics. Bohm's book does so. However I disagree that Bohm's approach is a good one. Instead, I would recommend Feynman's lectures on physics. Feynman's pedagogical treatment of quantum mechanics starts with two-dimensional Hilbert spaces. They are very useful because the reader understands that different bases (and operators) in the same Hilbert space may be equally important, and that the probabilistic interpretation of the amplitudes is absolutely essential.

The magician Uri Geller has convinced David Bohm that he (Geller) had supernatural abilities - a point that Feynman liked to ridicule. I am afraid that this transformation of Bohm at the end of his life might be related to his exaggerated emphasis on philosophical prejudices in quantum mechanics, as opposed to the pragmatic goal to extract useful predictions.

Quantum mechanics is weird. Sidney Coleman said that if thousands of philosophers had been trying, for thousands of years, to find the weirdest thing possible, they would have had never found a thing as weird as quantum mechanics. Nevertheless, quantum mechanics works, and we know that we can extract the information about probabilities of anything. (And the new insights about decoherence also explain where the difference between macroscopic and microscopic objects comes from.) In this sense I feel that the approach to quantum mechanics "Shut up and calculate" is a better one than wasting time with a wrong philosophy.

Despite the criticism, the book is cheap enough so that I can recommend you to buy it. David Bohm was an interesting person even though he was a communist.

Rating:
Summary: A thoughtful and very readable text
Review: This is perhaps still the best way to enter quantum mechanics. This book was not written in haste: there is depth in almost every page. Yet, very little is assumed of the reader, but that he has a genuine interest in learning the subject, and patience to read it sequentially, calmly, and ponder about it. There is, then, no better guide.Do not think you will miss the computation techniques: they are all there. This is a complete book. It will teach you the orthodox view. Then, if you care, read the other books by Bohm, to learn of possible alternatives.