Skip to main content

Computing with Quantum Cats – John Gribbin ****

A new John Gribbin book is always a delight, and he is at his best when exploring the bizarre possibilities of quantum theory. If you aren’t familiar with his previous books on the subject, the title here might be worrying as it suggests some fiendish bio-electronic device where collections of unwilling cats are wired into a computer, but in fact it’s a follow on from earlier titles In Search of Schrödinger’s Cat and Schrödinger’s Kittens, where the relevance of the cats to the topic has become increasingly strained.
What we have here is an introduction to the wonderful world of quantum computers. Usefully, Gribbin leads us in through conventional computing, with workmanlike short biographies of Turing and von Neumann to help make the route to understanding what is going on in devices we use every day, but of which we have little comprehension, much clearer. It’s good to have a computing history that fully takes into account the British contribution, often sidelined by US work, in part because of the way Churchill unfortunately insisted that most of the UK wartime work be destroyed.
The second section of the book takes us into quantum theory, using Richard Feynman and John Bell as the key biographies, while the third concentrates on quantum computing, leading on the perhaps rather less obviously central character of David Deutsch and taking us through some of the many mechanisms for building a quantum computer that are currently being worked on.
Overall this works very well, and we get a powerful insight into the capabilities of this remarkable technology and the huge challenges that are faced in making it work reliably. To get any idea of how quantum computers work it is necessary to give a good background in quantum theory itself, and this is something that Gribbin can do with one hand tied behind his back. It is indicative of the strange nature of quantum theory that when writing on the subject, I take a very different line on some aspects – notably the many worlds interpretation – and yet both views are currently unassailable. You might even say superposed.
If I have any criticism it is that some areas are brushed over just a little too lightly – this isn’t the book to really get a total low-down on quantum physics as it isn’t its central topic. This means that there are a few places were Gribbin effectively says ‘this happens, but you don’t need to understand it.’ The only specific topic I do think could have been handled better is the very important concept of decoherence, which (unless I missed it) is introduced without ever explaining what it means. Certainly in the first reference to it in the index it is used as if it is obvious what it’s about. Yet in reality it is a subtle concept that is hugely important to the quantum computing business. I really wish there had been a few pages putting this straight.
Overall, without doubt the best book I’ve read to provide the general reader with an introduction to quantum computers, and given their potential importance in the future, that has to make it a brilliant addition to any popular science enthusiast’s shelf.

Hardback 

Kindle 
Using these links earns us commission at no cost to you
Review by Brian Clegg

Comments

Popular posts from this blog

Shape - Jordan Ellenberg ***

I really enjoyed Jordan Ellenberg’s earlier book How Not to be Wrong , so looked forward to Shape with some anticipation. In principle what we have here is a book about geometry - but not seen from the direction of the (dare I say it) rather boring, Euclid-based geometry textbooks some of us suffered at school. Instead Ellenberg sets out to show how geometry underlies pretty much everything. Along the way, we are given some nice turns of phrase. I enjoyed, for example, Ellenberg’s remark on the philosopher Thomas Hobbes, where Ellenberg remarks Hobbes was ‘a man whose confidence in his own mental powers is not fully captured by the prefix “over”’.  Whether or not what we read about here is really all geometry is a matter of labelling (as is the ‘number of holes in a straw’ question that Ellenberg entertainingly covers). Arguably, for example, there is some material that is probability that can be looked at in a geometric fashion, rather than geometry that produces probabilistic result

Bergita and Urs Ganse - Four Way Interview

Bergita and Urs Ganse are siblings and the authors of The Spacefarer’s Handbook – Science and Life Beyond Earth , a translation of their German book, published by Springer in 2017. Urs is a theoretical space physicist, with a research focus on plasma simulations and works at the University of Helsinki in Finland. He uses supercomputers to model the near-Earth plasma environment and its interactions with Earth's magnetic field. Bergita is a university professor at Saarland University in Germany, an orthopedic surgeon and a physiologist. Her research focuses on the musculoskeletal system in spaceflight. She is a co-investigator of an ISS experiment, and she teaches Space Medicine to university students. Why Space?  Urs: I guess we were exposed too much to science-fiction as children. We watched Star Trek every day, read books about space and played computer games. Somehow, spaceflight became a solid part of our normal understanding of the world. Ever since then, it has seemed kind of

The Beauty of Chemistry - Philip Ball ***

To do this review fairly, I ought to point out that I'm not a great fan of books where the images dominate the text - a more visually-oriented reader may appreciate the book more than me. However, there is enough text here by Philip Ball to lift what could otherwise be little more than a coffee table book. The text I'd definitely give four stars, but in the end, the dominance of the imagery by Wenting Zhu and Yan Liang pulled it down to three stars for me, because I did still find, for example, the number of pages of pictures of bubbles or crystals (for example), started to get a bit samey. From the opener on bubbles we go on to the inevitable chapter on crystals - surely chemistry's visual superstar. I was disappointed not to see Roger Hiorn's 2008 work Seizure featured, when the artist covered a bedsit with copper sulfate crystals. I think this reflects a weakness in the visual approach, which gives us the chemical imagery in isolation from the real world - a crystal