Chris Bernhardt's Reading List

"This is a history of the theory of computation. It introduces all the most important people and you see the development of the ideas. So, first of all, Alan Turing came up with what computation is. Then John von Neumann wanted to design hydrogen bombs and needed a computer to do that. So he took some of Turing’s ideas to design a computer. Then we come to Richard Feynman with quantum physics and David Deutsch and John Stewart Bell. There are little biographies of each of them. Yes. What you don’t get is a good feeling for what quantum computing is, because I don’t think you can get that without doing some mathematics. But if you’re completely math-phobic and you want to read a quantum computing book, this is a very good one for the underlying history and an introduction to the founders of the subject. It’s difficult to say what the applications are going to be. I certainly think that chemistry could become very, very different in the next decade. Probably the most major change is going to be that kids in school are going to be learning about quantum computing and playing with little quantum computers. It’s going to have more of an impact in education, I think. Teleportation is possible and it’s been done many times. What we’re talking about is teleporting the states of qubits. A Chinese team has actually teleported a qubit from Earth to a satellite in low earth orbit. Quantum teleportation is here and it’s used for communication—but we’re nowhere near teleporting people! You should take 2 to the power of the number of qubits and that tells you how many bits you’re talking about. If you’ve got five qubits, that’s the size of one of IBM’s quantum computers: that’s 32 bits. It’s a mixture. A lot of descriptions oversimplify things and say it’s a parallel computation. It isn’t really a parallel computation, because you’ve got all these rules about what happens when you measure qubits and so on. When you learn about quantum computing the first thing you begin to wonder is whether you can actually do anything with it because the rules seem so strange. But in fact you can. There’s work being done on photosynthesis, for instance. You want to be able to convert sunlight into energy—to be stored in batteries, for example. That’s a quantum process and it’s being studied using quantum computers. It really does have potential."

"Both this book and the next book I’ve recommended, Quantum Computing for Computer Scientists, mention Quantum Computing and Quantum Information (the fifth book on my list) as the real reference book. Both these books say they are, in some sense, introductions to that book. What I really like about the Riley book, Quantum Computing from the Ground Up, is the description of Bell’s Inequality and what that means. If we go back to the 1920s and 30s, when quantum mechanics was first being described, Einstein really disliked it. He really felt that this idea in quantum physics of things jumping when they are measured, of probabilities coming in, shouldn’t be there. He didn’t like the idea of entanglement, where you have what he described as “spooky action at a distance.” So, he felt it was fundamentally wrong and there was a dialogue going on between Einstein and Bohr about what physics was and whether quantum mechanics was the correct way of describing things. In the 1960s John Stewart Bell came up with a really clever experiment. He realized you could distinguish between the theory that Einstein was describing and the standard, Copenhagen theory that Bohr was in favour of. He devised this test, which has subsequently been performed several times, and it’s always come out in favour of Bohr and the Copenhagen description. “I think quantum computing is going to become part of the standard education, certainly of computer scientists and perhaps of most scientists.” This is a really important test and not just for historical reasons. It’s also because as you begin to learn a little bit about quantum phenomena you feel—or at least I did—much like Einstein, that there must be some sort of deeper theory, that it’s got to be simpler, that it can’t really be this strange. I think most people feel that way when they come across quantum mechanics. This test shows you quantum mechanics really does have these strange properties. And then of course once you’ve got a clever idea you want to use it in other ways. The idea behind Bell’s test is now used in many encryption techniques, to encrypt data. It would have been really interesting to see what he made of it. It’s too short to be a textbook, I think. In a couple of places, it’s very terse. What’s very good about it is that it’s got lots of very clear, worked examples that you can read through. It’s a really good book if you want to learn about quantum computing on your own."

"This is not a beginner’s quantum computing book, but if you already have some experience with some of the ideas of quantum computing then this could be the book for you. Scott Aaronson works in complexity theory, which is about how difficult problems are. So, for example, when we encode data, we want that to be easy, but for someone to break it, we want that to be hard. The classification of the levels of difficulty is the sort of problem Aaronson works on. Support Five Books Five Books interviews are expensive to produce. If you're enjoying this interview, please support us by donating a small amount . This book wanders all over the place. I wouldn’t say it’s a linear book at all. He’s got ideas about how human minds work, about what free will is, about time travel. He mixes quantum computing in with philosophy and mathematics. It’s a mixture of these things, but he’s obviously thought very deeply about them. All sorts of interesting things crop up in the book and then he’s got really interesting things to say about them. And he’s got this very jokey style. There are nerdy jokes throughout the book which either you like or you dislike. I happen to like them. It’s a very entertaining book. In terms of difficulty the book is very varied. Parts of it are very difficult, parts of it are easy, but it’s a book that’s worth reading. He’s got all sorts of ideas that are worth thinking about. It’s a really thought-provoking book. It is. He’s a little opinionated, but he’s really intelligent and gives excellent explanations of why he is right and others are wrong! We’re out of my area of expertise, but Democritus was talking about atoms, so in some sense, I guess. He does start with Democritus, but it’s not a big part of the book."