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 
Review by Brian Clegg

Comments

Popular posts from this blog

The Art of Statistics - David Spiegelhalter *****

Statistics have a huge impact on us - we are bombarded with them in the news, they are essential to medical trials, fundamental science, some court cases and far more. Yet statistics is also a subject than many struggle to deal with (especially when the coupled subject of probability rears its head). Most of us just aren't equipped to understand what we're being told, or to question it when the statistics are dodgy. What David Spiegelhalter does here is provide a very thorough introductory grounding in statistics without making use of mathematical formulae*. And it's remarkable.

What will probably surprise some who have some training in statistics, particularly if (like mine) it's on the old side, is that probability doesn't come into the book until page 205. Spiegelhalter argues that as probability is the hardest aspect for us to get an intuitive feel for, this makes a lot of sense - and I think he's right. That doesn't mean that he doesn't cover all …

The Best of R. A. Lafferty (SF) – R. A. Lafferty ****

Throughout my high school years (1973–76) I carefully kept a list of all the science fiction I read. I’ve just dug it out, and it contains no fewer than 1,291 entries – almost all short stories I found in various SF magazines and multi-author anthologies. Right on the first page, the sixth item is ‘Thus We Frustrate Charlemagne’ by R. A. Lafferty, and his name appears another 32 times before the end of the list. This isn’t a peculiarity of my own tastes. Short stories were much more popular in those days than they are today, and any serious SF fan would have encountered Lafferty – a prolific writer of short fiction – in the same places I did.

But times change, and this Gollancz Masterworks volume has a quote from the Guardian on the back describing Lafferty as ‘the most important science fiction writer you’ve never heard of’. Hopefully this newly assembled collection will go some way to remedying that situation. It contains 22 short stories, mostly dating from the 1960s and 70s, each w…

David Beerling - Four Way Interview

David Beerling is the Sorby Professor of Natural Sciences, and Director of the Leverhulme Centre for Climate Change Mitigation at the University of Sheffield. His book The Emerald Planet (OUP, 2007) formed the basis of a major 3-part BBC TV series ‘How to Grow a Planet’. His latest title is Making Eden.

Why science?

I come from a non-academic background. None of my family, past or present, went to university, which may explain the following. In the final year of my degree in biological sciences at the University of Wales, Cardiff (around 1986), we all participated in a field course in mid-Wales, and I experienced an epiphany. I was undertaking a small research project on the population dynamics of bullheads (Cotus gobio), a common small freshwater fish, with a charismatic distinguished professor, and Fellow of the Royal Society in London. Under his guidance, I discovered the process of learning how nature works through the application of the scientific method. It was the most exciting t…