Quantum Computing for Everyone (Mit Press) Paperback – Illustrated, September 8, 2020

Despite being around for decades, the words “quantum mechanics” still make eyes roll even in a room of educated people. Few really understand the phenomena. Among those more scientifically minded, some – thankfully fewer in number – still argue that quantum mechanics will give way someday to a more classical approach. The controversial part of quantum mechanics, which foiled even Albert Einstein, states that to measure the spin or velocity of an electron, one must interfere with the system permanently. This enmeshment of the measurer with the system confuses people, but numerous experiments highlight this paradox. It seems to be an innate part of the universe, not merely a technological limitation.Smart physicists and mathematicians have noticed an opportunity around quantum mechanics: We can address computational questions with its approach. A system of “qubits” can be used to address problems that classical computing cannot address. This observation has produced a new scientific field of quantum computing. Recently, major companies have begun to jump into this technology in a quest for early supremacy.Most textbooks use a lot of math to introduce quantum computing – rightfully so because mathematics provide the basis towards all computation. But a math-heavy approach makes the field relatively inaccessible. To address this shortcoming, Chris Bernhardt provides an introduction to the subject with less mathematics. The book teaches basic linear algebra needed to approach the subject. It’s still heavy on the words, not the mathematics, and draws out applications and challenges that confront the field.Since a child, I have loved mathematics and its creative expressivity. I enjoyed how Bernhardt introduced me to relevant concepts and drew me into quantum concepts. By the end of the book, however, I glazed over the mathematics in favor of just getting the book completed. Perhaps that is a personal failing, but it’s one that I witnessed in many of my college math classes, too!I found the next-to-last chapter on quantum algorithms the least accessible, but the last chapter on quantum applications was the most interesting. Those in the investment community can find a deep dive into this topic helpful to carefully discover future winners and losers in this burgeoning field. Quantum computing presently requires a lot of money to access, but presumably, like classical computing, that cost will go down with time. This field is fascinating to think about, and Bernhardt makes it truly accessible “for (almost) everyone.”

Amazing reading experience, while enriching my knowledge of the quantum computer, algorithm, quantum phenomena involved. Definitely concise, very engaging book!!! Highly recommended!!!

My wish for in this book is "example" programs for a quantum computer, but the book givesgood background to quantum entanglement and some introductory programming ideas forways quantum computing can exceed the modern digital computer which has seemed to reacha performance plateau in the last ten years with 2025 computers not being so very much better than 2015 computers. Claims for quantum computing seem to have exceeded their actual performance in the real work even after billions being spent in their research. AI was in this very same place 10 years ago, and has now, very much came into use by web link. Time will certainly tell in quantum computers.

I found Bernhardt's book to be both an extremely accessible and rigorous introduction to quantum computing. The writing is very good and the book has elements of a good story with one topic feeding well into the next. One unusual feature of the book is that it treats quantum computing over the reals rather than the complex numbers, with indications here and there how things would be different over the complex numbers.The book starts off with a nice account of the Stern-Gerlach experiment to explain spin, mentioning how the same conclusions can be arrived at simply by using polarised filters and ordinary light. There is then a self-contained chapter on linear algebra as a physicist sees it, using bras and kets. The book then progresses to talk about qubits, entanglement, and a host of other topics.The topics I enjoyed most were the following: (i) The description of the BB84 protocol for determining if someone is eavesdropping on a communication line, (ii) the description of entanglement, including physical means of entangling qubits (though I supplemented the material with information from the Internet), (iii) the discussion of Bell's Theorem, Einstein's views and hidden variables (again I supplemented with information from the Internet), (iv) the discussion of quantum gates, (v) the no cloning theorem, (vi) quantum teleportation and (vii) the discussion of the Deutsch, Deutsch-Jozsa and Simon problems and algorithms. The coverage of Shor's and Grover's algorithms were too sketchy for me to follow well. Perhaps a sequel will cover these more rigorously.All in all a very lucid and enjoyable intro to quantum computing that I recommend highly!