Reviews for Quantum Mechanics

The average rating for Quantum Mechanics based on 2 reviews is 4 stars.

Review # 1 was written on 2019-06-28 00:00:00 Judy Coup This is a traditionally designed, fairly advanced (at upper undergraduate level), and pretty solid book on (mostly non-relativistic) quantum mechanics. The author satisfactorily addresses all the traditional themes of a typical textbook (the basic postulates, the Schrödinger equation in one and three dimensions (with all the typical boundary conditions scenarios), angular momentum, commutation relationships, time-dependence, the Ehrenfest theorem, many-particle systems (including entanglement, the EPR "paradox", and an introductory treatment of the spin-statistics theorem), "hydrogenic" atoms, the helium atom, various types of approximation methods etc.); it is one of this book's strengths however that it does not stop here, but is also discusses traditionally less frequently covered (but equally important) subjects such as: a very interesting introduction to measurement theory and its interpretative issues, all the main typologies of perturbation methods, spin-orbital momentum coupling, different scenarios of scattering, and even more directly applicative areas such as quantum cryptography, teleportation and quantum computing. Particular subjects that a few textbooks tend to by-pass or only briefly discuss, such as degeneracy, are also addressed quite well and in a relatively comprehensive manner for such an essentially introductory book. The book is mostly focused on non-relativistic quantum mechanics, but there is also a reasonably good (although pretty basic), introductory section on the Dirac equation and some rudiments of quantum field theory. This book follows a traditional approach heavily based on a (mostly) rigorous mathematical treatment, but it is also aims at the same time to elucidate, with reasonable clarity and a fairly good rate of success, the conceptual basis of all items presented by the author. Fortunately, the reader is also spared the typical historical treatment of the first developments of quantum mechanics, which is something that has been all-too-often administered ("inflicted" might be a more adequate word) as an introductory chapter to the patient and unwary reader. Yes there is a very brief introduction to the usual culprits (the photoelectric effect, the Compton effect, atomic line spectra etc.) but it is short, concise and to the point. As a less-positive note, the author uses the representation-free Dirac notation very sparingly, mostly focusing on the direct integral/differential representation instead. I freely acknowledge that this is mostly a question of personal tastes and experience, but I do prefer books that allocate a preferential treatment to the Dirac notation (which I find elegant, concise, powerful and with a simple but robust "grammar" designed in such a way as to prevents many mistakes. Moreover, with the Dirac notation you can easily distinguish between scalars, vectors, operators, inner products, outer products, etc. An example of such approach that I particularly enjoyed is the famous and excellent book by Sakurai - see my review here: ). The author tends also to avoid using the linear algebraic approach (what he calls the "matrix method"), providing the explanation that such methods are generally clumsy when dealing with infinite-dimensional vector spaces: I personally tend to disagree with this view, as a set of flexible techniques is now available in contemporary mathematics, that allows a fairly robust and relatively straightforward treatment of many infinite-order linear algebraic manipulations. It should also be noted that, in terms of stability and convergence of available numerical approaches, the problems found with such manipulations do present themselves also when using the partial differential equations method. But, of course, there are areas (such as the intrinsic angular momentum components of a spin-half particle, where the Pauli matrices are just too handy), where the author is forced somewhat grudgingly into adopting the matrix representation approach While the overall quality of the book is pretty good, I must say that the quality of the treatment of the various subjects is at times a bit uneven: there are many subjects (such as the conceptual apparatus of quantum mechanics and related issues, perturbation theory, the variational principle, and scattering) that are done brilliantly and are a real pleasure to read, but there are also some other subjects (such as quantum computing, for example) that are developed quite poorly, are quite confusing and feel quite rushed. There are also a couple of areas where the author should have been more precise from a conceptual perspective: for example after equation 8.6, where he states that "sign of the wave-function has no physical significance": I disagree with such as generic statement, as the phase of a wave function can definitely have physical significance, simply because of the possibility of interference. In that sense, the phase of a wave function is no less physically significant than the magnitude, as you need both in order to predict the results of any nontrivial experiments. Probably the author should have stated here that the phase has no DIRECT physical significance, or something also these lines. There are also a few (thankfully, not many, and usually quite easy to identify) typos that are not even fixed in the errata of the book - this is not a major issue, but quite disappointing in a book that went already through several editions and re-prints (there are errors in relation to some widely treated items in literature, such as the Clebsch-Gordan coefficients and the derivation of the Ehrenfest theorem, that just by a quick comparison with what is easily available on the Net would have (should have) been quickly identified and rectified). There are also a couple of areas where there is a bit too much hand-waving, and a couple of points where the author skips some steps (providing instead a statement that such steps are complex or non-standard), while this is not really the case at all: for example, just before equation 8.33 where he states that "the integral can then be evaluated by standard (though not elementary) methods" while in reality the integral can be easily solved with a quite trivial, run-of-the-mill substitution of variable. Considering all the above, it is pretty clear that the book could definitely be improved upon, however it is still a fairly good text, highly informative, of generally good quality and deserving recommendation. Would have I still invested my time reading it, even with these areas of improvement? Definitely yes. 3.5 stars (which I could not round up to a 4 as it would have been unfair to similar texts that are of slightly better quality and that I rated with a 4-star grade).

Review # 2 was written on 2020-01-26 00:00:00 Marsha Johnson Very, very good. Gilder does an excellent job of capturing the personality, fervor, and excitement of a bunch of men who reinvented the universe. This book gives a cogent and smart account of how we got some very complex ideas. Read it.