Chris BernhardtKirja-arvosteluja

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.”

A relatively easy-reading treatment of what everyone should know about computability theory, centered around Alan Turing's 1936 paper ("On Computable Numbers ...") but also including good coverage of finite automata, universal-computability models other than Turing machines, and Cantorian cardinalities and diagonalization proofs. Editing slips such as missing words are rather too numerous.