# Quantum I'm looking for a Quantum Mechanics textbook

1. Mar 23, 2017

### anachin6000

The title kind of says it all, but I'm searching for a textbook that has a heavy theoretical approach. Could someone help me with a recommendation?

2. Mar 23, 2017

### PeroK

Is this a first text book or advanced?

3. Mar 23, 2017

### anachin6000

First.

4. Mar 23, 2017

### PeroK

5. Mar 23, 2017

### dextercioby

JJ Sakurai's book is brilliant (well, I don't like his lack of mathematical rigor, but that's just me), but not as a first text/exposure to the interesting world of quantum physics.

6. Mar 24, 2017

### atyy

For a first book, philosophy is more important than theory, so I recommend Landau and Lifshitz. Weinberg is also good.

7. Mar 24, 2017

### vanhees71

For a first book philosophy is confusing (it's confusing even for the advanced physicist) and not very helpful concerning the understanding of the hard facts about QT. I don't understand, how you can recommend Landau and Lifshitz and Weinberg with the argument "philsophy is more important than theory"! I'd recommend these very books for the opposite reason. They do not contain unnecessary philosophical gibberish but follow a "no-nonsense approach". I like Landau and Lifshitz, but for my taste it's too much "wave-mechanics centered" in its approach rather than starting in the very beginning with the Dirac approach, which makes the underlying logic of QT much more explicit than using a specific representation (i.e., the position representation). I'd however not recommend Weinberg as a first read, because it's pretty advance (but of course brilliant as any textbook by Weinberg). If I had to teach QM1, I'd still recommend J. J. Sakurai's book, from which I learnt QT as a student in my QM1 lecture.

8. Mar 24, 2017

### Demystifier

By "philosophy", I believe that atty means an emphasis on concepts rather than techniques of calculation. In that sense, I would agree that concepts are more important than techniques in a first exposition to QM.

9. Mar 24, 2017

### dextercioby

In other words (4), more text, less formulas.

10. Mar 24, 2017

### Demystifier

Sort of, but it's also important that most formulas are short so that one can comprehend their conceptual meaning at a single glance. An example would be the equation for the Green function written as
$$LG=1$$
where $L$ is a differential operator. But then again, perhaps this particular equation is too abstract for a first exposition, so one has to explain in a longer formula what such compact notation really means.

11. Mar 24, 2017

### smodak

A good theoretical book on Quantum Mechanics is Gottfried https://www.amazon.com/Quantum-Mechanics-Fundamentals-Graduate-Contemporary/dp/0387220232

By the way, if you provided us a little bit of your background, your current knowledge of math and physics, and why you want a book, it would have been easier for us to recommend what may be most appropriate for you.

Last edited by a moderator: May 8, 2017
12. Mar 24, 2017

### vanhees71

Hm, I hate textbooks with a suada of words like "as one easily sees, the following theory of everything is valid" instead of writing the one or other formula to derive it! Take Sommerfeld's 6-volume lecture series: Many formulae with the right amount of words. The result is a didactic master piece. If you look at the list of his pupils, it should be proof enough that this is the way theoretical physics should be taught!

13. Mar 24, 2017

### Andreol263

Griffiths is terrible, it's just a minor step up from basic introductory modern physics texts, and it appears to be allergic to dirac notation.
I Would recommend Shankar's Principles of Quantum Mechanics, for it being extremely well self-contained and very didatic and fun to learn from, and the exercises are in the right spot :D

14. Mar 25, 2017

### atyy

Yes, ideally we should combined the philosophy of Landau and Lifshitz or Weinberg with the the Sakurai starting with spin 1/2. I like the calculation part of Sakurai, unfortunately he doesn't do philosophy that well, so I still recommend L&L or Weinberg for that.

15. Mar 25, 2017

### vanhees71

Hm, I don't find much "philosophy" in either of these books; perhaps most is in Weinberg's about "interpretation".

16. Mar 26, 2017

### atyy

Well, the typical L&L is to do the minimum but clearest of everything :)

17. Mar 27, 2017

### vanhees71

Yes, concerning "representation" L&L is very good, at least there's no collapse ;-).

18. Mar 27, 2017

### atyy

L&L have collapse :)

Actually their collapse part is a bit old fashioned, but it's still much better than having no collapse.

19. Mar 27, 2017

### Demystifier

Oh no, not again!

L&L do not use the word "collapse", but they certainly do introduce a non-unitary process. At page 24 they say (my bolding):
"We see that the measuring process in quantum mechanics has a "two-faced" character: it plays different parts with respect to the past and future of the electron. With respect to the past, it "verifies" the probabilities of the various possible results predicted from the state brought about by the previous measurement. With respect to the future, it brings about a new state (see also §44). Thus the very nature of the process of measurement involves a far-reaching principle of irreversibility.This irreversibility is of fundamental significance. We shall see later (at the end of §18) that the basic equations of quantum mechanics are in themselves symmetrical with respect to a change in the sign of the time; here quantum mechanics does not differ from classical mechanics. The irreversibility of the process of measurement, however, causes the two directions of time to be physically non-equivalent, i.e. creates a difference between the future and the past."

Clearly, irreversibility implies non-unitarity. It is a matter of interpretation and semantics to explain whether this non-unitarity is or isn't the same as collapse. But it seems to me that for L&L this non-unitarity is a physical process, and not merely an update of information. So it would be really illuminating if vanhees could clarify how exactly this L&L's irreversible physical process can be different from collapse.

Last edited: Mar 27, 2017
20. Mar 27, 2017

### Demystifier

Yes, but physics is not only theoretical physics. A first book on a topic such as QM should be understandable to all physicists.