This book series, written by Nobel prize winner Claude Cohen-Tannoudji and coworkers Bernard Diu and Frank Laloë, is truly a masterpiece of quantum mechanics knowledge. In our book review: Cohen-Tannoudji – Quantum Mechanics, we review the second German edition; however, most of what we say should apply to the

French and English editions. The series contains two books, with together around 1400 pages, enough for any quantum physics exam. Each chapter contains a supplement with additional information that is helpful but can be skipped during a first read. This may actually help to get through all of the 14 chapters.

The chapters in the first book cover particles and waves, the mathematical framework of quantum mechanics, the postulates of quantum physics, and simple systems. It concludes with the harmonical oscillator and the angular momentum in quantum mechanics. The second book covers particles in a central potential, elementary scattering theory, and the spin of the electron. Then it continues with the addition of angular momentum, stationary perturbation theory, and the fine and hyper-fine structure of the hydrogen atom. The second volume concludes with approximation methods for time-dependent problems and systems of identical particles.

In short, the book series covers anything you want to know about quantum mechanics. An abundance of images, formulas, and exercises make this the probably best book series for physics students. So let’s have a deeper look into the details.

## Motivation for quantum physics

The first paragraph in volume one clarifies that classical mechanics is not enough. It is mentioned that the existence and properties of atoms need quantum mechanics for their description. And so is chemical binding and the movement of electrons. The introduction makes very clear that classical physics is only an approximation of quantum physics for large particles. Interestingly, it is also mentioned that classical mechanics is only an approximation of special relativity for particles that are slow compared to light.

The fantastic introduction continues with the particle-wave duality, first for photons, then for massive particles. The introduction explains Neil Youngs double-slit experiment. It also explains spectral decomposition of polarized light as well as energy quantization of atoms. The first 31 pages — corresponding to 20 pages of size Din A4 — contain a lot more. They cover the Schrödinger equation, particles in a time-independent potential, and *derive* Heisenbergs uncertainty relation. In summary, all motivation we would expect from a great introduction motivation is covered. We can, therefore, easily award five stars for the motivation.

## Images

Not only is the text in this book great, but there are also quite some images (black and white only). This helps a lot for understanding the text. We counted around 280 images. The roughly 1400 pages correspond to about 892 pages in format Din A4. Thus, there are more images than one per each four A4 pages, but less than one per two A4 pages. According to our review principles for quantum physics books, we can thus award four stars for the images in this two-volume series.

## Formulas

When it comes to formulas in Cohen-Tannoudjis and coworkers book, there is only one word: Abundance! On the roughly 1400 pages of the two books, we counted roughly 5700 numbered formulas. That’s a lot: More than four formulas per page on average. If you would consider the equivalent number of A4 sized pages even more than six formulas per pages. So far a record among the books we reviewed.

But how about the correctness of the formulas? Well, looking at our own comments on the book we have found comparatively few mistakes. However, we may have missed a lot, and unfortunately, we haven’t found any official errata list. Anyways, according to our review principles we should award all five stars for formulas.

## Quantum Physics Exercises

We counted altogether 114 exercises spread over the two books. This is quite a lot, specifically when some of the exercises are so extensive that their statement takes two or three pages. It is certainly more than one exercise per 10 pages of size A4. We, therefore, award two additional stars (to the minimum of one star). We award another additional star since there are a few solutions to exercises, but far from all. Thus, the exercise category gets four stars altogether.

## Comparison to Other Quantum Mechanics Books

The quantum mechanics book by Feynman is less technical and more conceptual, with a lower number of calculations. On the plus side, the calculations in Cohen-Tannoudji et al. are fairly simple. This makes the book also easier to read than e.g. the quantum mechanics book by Landau and Lifshitz. For a more complete overview, including even simpler books, have a look at our comparison of quantum physics books.

## Summary of the Book Review: Cohen-Tannoudji – Quantum Mechanics

To summarize our book review: Cohen-Tannoudji – quantum mechanics, it is probably the most complete book series about quantum mechanics there is. That alone makes it worth the money, and it is not inexpensive. But the old saying you get what you pay for applies here. With a great motivation, lots of images, an abundance of formulas, and many exercises, partly solved, this book deserves our blessings. If you are truly serious about learning quantum mechanics, you should consider getting both volume one and two. You may save some bucks by buying the two volume set or choosing the *used books* options under the links. Alternatively, you may want to check out our complete list of best quantum physics books for beginners.

Motivation: | (5.0 / 5) |

Images: | (4.0 / 5) |

Formulas: | (5.0 / 5) |

Exercises: | (4.0 / 5) |