Bits on Quantum Information

Abstract

I was honored to see my book Quantum Information: An Overview (Springer, 2007) reviewed alongside David Mermin’s masterful new textbook ( Quantum Computer Science: An Introduction, Cambridge University Press, 2007). However, I was disappointed by reviewer Barbara Terhal’s facile and inappropriate approach (Physics Today, Physics Today 0031-9228 61 3 2008 54 https://doi.org/10.1063/1.2897953. March 2008, page 54 ).Terhal states, “The preface of the book speaks of his intentions: to write a text that provides an overview of the fundamentals of the field.” However, my intent, which was thoroughly laid out in the preface, goes far beyond that characterization. As a result, my necessary constraints on the book are misrepresented and underappreciated. In particular, I made it clear that the book was intended as “a handy reference … that also treats foundational aspects of quantum mechanics connected with quantum information science.” Unlike Mermin’s excellent monograph, mine was never intended to serve as an easily read introduction to the field or to provide unique insight. An overview such as mine cannot be the same thing as a textbook and should not be evaluated as one.Terhal further complains that the monograph contains little by way of personal insight, but that point was made clear both in the foreword by Tommaso Toffoli and in the preface. When presenting a subject as nascent and controversial as quantum information science, it is a good idea, particularly in the case of an overview, not to inject too much of oneself.More surprisingly, after recognizing that my book does provide a comprehensive overview of this rapidly expanding area, the reviewer questions “whether there is an audience for such encyclopedic texts, especially given the easy access to online sources of information such as the arXiv e-print server and Wikipedia.” That question is relatively easily answered: Yes, there is periodically a need for a concise and comprehensive monograph that is above the anarchy and distortions on Wikipedia and to a lesser extent the e-print servers and that can serve those with mathematical training and limited free time to cull accurate treatments from the Web.Moreover, because quantum information science is an area that transcends physics itself, the physics itself can sometimes be distorted, a situation more prevalent in online offerings such as Wikipedia and e-prints. Can one seriously rely on Wikipedia and e-print servers as clear and valid guides to the foundation and breadth of quantum information science? Are those the sources where researchers outside the area can obtain an organized overview of the subject? The unevenness and unreliable nature of the perspectives offered on free portions of the Web are reasons why I chose to write Quantum Information in the first place.Another aspect of my monograph, also clearly noted in its preface, is that the book discusses “a number of pertinent … results from earlier decades of the twentieth century … because they will likely prove important to future progress in both quantum mechanics and information theory.” Terhal’s only mention of that aspect was apparently her reference to the unspecified portion of the text she considered “mathematical and superfluous detail.” My reason for including that extra material is to show the extent to which quantum information science is grounded in fundamental physics and is capable of making great contributions to quantum foundations, provided the physics remains squarely in view.Like a standard quantum measurement, the effect of this lukewarm book review is, in all likelihood, irreversible. Fortunately, though, many who have carefully read the book’s preface and who, therefore, have understood the entirety of its purpose and constraints have expressed their satisfaction with the book over the 16 months since its publication. Those readers have been glad to have a reliable source to guide them into this exploding body of literature.© 2008 American Institute of Physics.