Computing with Quantum Cats: From Colossus to Qubits

by John Gribbin

The quantum computer is no longer the stuff of science fiction. Pioneering physicists are on the brink of unlocking a new quantum universe which provides a better representation of reality than our everyday experiences and common sense ever could. The birth of quantum computers – which, like Schrödinger’s famous ‘dead and alive’ cat, rely on entities like electrons, photons or atoms existing in two states at the same time – is set to turn the computing world on its head.In his fascinating study of this cutting-edge technology, John Gribbin updates his previous views on the nature of quantum reality, arguing for a universe of many parallel worlds where ‘everything is real’. Looking back to Alan Turing’s work on the Enigma machine and the first electronic computer, Gribbin explains how quantum theory developed to make quantum computers work in practice as well as in principle. He takes us beyond the arena of theoretical physics to explore their practical applications – from machines which learn through ‘intuition’ and trial and error to unhackable laptops and smartphones. And he investigates the potential for this extraordinary science to create a world where communication occurs faster than light and teleportation is possible.

Genres: Science, Nonfiction, Physics, Computer Science, Computers, Technology, Popular Science

304 pages, Paperback

First published June 20, 2013

About the author

John R. Gribbin is a British science writer, an astrophysicist, and a visiting fellow in astronomy at the University of Sussex. His writings include quantum physics, human evolution, climate change, global warming, the origins of the universe, and biographies of famous scientists. He also writes science fiction.

Reviews

[Tom Fewings · Rating 3 out of 5]

The first two thirds chart developments in computing and quantum mechanics. Well written and highly aware of the incomprehensible nature of it's subject matter, it certainly cleaned up my understanding of the two subject. The last third is on the current state and future of quantum computing. This left me sitting in the dust like a simpleton, awaiting the next Christmas when a relative hands me another book beyond my comprehension because they heard I was in to 'science'.

[Dan Smith · Rating 3 out of 5]

Started out great, it was a nice introduction talking about Alan Turning and his code breaking machine. And how he wasn’t actually interested at all at making what we know as a computer for domestic use after his code breaking achievement. Some of the stuff in this section describing the logic behind the machine he made started to go over my head. And I’ve highlighted it to look back over it, as the descriptions were short and seemed to assume knowledge. But I got the gist of it and I left approx the first half of the book in good knowledge.

Then it started to get pretty bad, more scientists were getting mentioned what seemed like each turn of the page. With each of the scientists getting their life story (which for the most part was unnecessary). This made the book very hard to read for me, as the Physics got harder to grasp, I really wanted the author to describe what was happening coherently, but it all just seemed to describe something - jump to another scientists - jump back to what he was talking about and so on... so on....

I think there is a lot of good content in this book, and I don’t doubt what the author writes. I think that what he puts forward especially at the end looking at Quantum dots etc. could be really interesting, but by that point I just wanted to get the book over and done with. However I think I’ll need to take another course in Quantum for my 4th year of my degree to be able to read it with ease. It was a much harder read than I was expecting...

It’s definitely not for someone with zero background knowledge, and I feel for someone that actually attempts to read it with no background.

[Brian Clegg · Rating 4 out of 5]

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.

Review first published on www.popularscience.co.uk and reproduced with permission.

[☘Misericordia☘ ⚡ϟ⚡⛈⚡☁ ❇️❤❣ · Rating 5 out of 5]

Q:
“I feel that I shall meet Morcom again somewhere and that there will be some work for us to do together…. Now that I am left to do it alone I must not let him down.” (c) Alan Turing.

[Reuben Barnes · Rating 4 out of 5]

you can tell John Gribbin is incredibly passionate about the field of quantum computing. so you might be disappointed to discover that he doesn’t exactly follow the Principle of Least Time when getting to the quantum stuff - you’re getting an entire history of computing first, whether you like it or not. once you accept that, and accept the fact that *nobody* really understands a lot of the science described here, it’s really really cool and exciting

[Jim · Rating 4 out of 5]

Source:2024RJXmasMadMoneyBookFund
Source: Libby E-book, Own a softbound
Notes on Kindle Published.

Writing this as I read. This book has some of the more lucid explanations of the quantum world I have seen. The book is a little dated written in 2013 however had plenty of things that were new to me. Gribbin starts with explanations of general computing with a chapter on Turing and Von Neumann and progressed on to Quantum chapters on Feynman, Bell and Deutsch and ends with a survey of possible technical directions, advantages/disadvantages and the problems that must be addressed for a workable computer. Note at the time of the writing , the only quantum computer could factor the number 15. So we have gone a long way since then.

https://www.nextbigfuture.com/categor... is a link to more recent developments.

Interested in how photons are entangled in the first place.
Here is what Google AI says:
Photons that are "entangled" are pairs of photons that are linked together in a quantum mechanical way, meaning that measuring the state of one photon instantly reveals the state of the other, even if they are separated by a large distance;

this occurs when the photons are created together through a process like spontaneous parametric down-conversion (SPDC), where a single photon is split into two correlated photons with entangled properties like polarization

A review and comparison to other books. https://fivebooks.com/book/computing-...

[el · Rating 4 out of 5]

fun

[Ravi]

this and natural beauty were my barbenheimer

[Kyle · Rating 4 out of 5]

The horrible history of computers begins with an attempt to crack enigmatic codes and quickly escalated to more effective ways to commit mass murder. Along the way, numerous bright minds stand out starting off with Alan Turing and Tommy Flowers, yet more and more migrate towards Los Alamos and the American universities fanning the Cold War paranoia flame. John Bell breaks through with his non-locality theorem and the subatomic world comes alive and helps make the room-sized computer smaller, leading to the next quantum leap with proof of the Many Worlds in qubit interaction. Perhaps the cart of being put before the horse, and our current interest in the quantum Internet is really just a symptom of the Universe showing knowledge of itself through us, but Gribbin stays on the FAPP-side of superpositioning processors, often referring to the Schrödinger kittens he previously wrote about to cover the unknowable discord happening at the lowest levels of reality, soon to be found in our pockets.

[Shubhankur Suvansh · Rating 4 out of 5]

Another brilliant book from John Gribbin. This is my second Gribbin book. He is a prolific writer and this is one of the best of his works. The book, to quote the author, "starts with Alan Turing and the need to crack codes and ends with Turing's heirs and the need for uncrackable codes"

It is divided into three parts - 1. Computing. 2. Quanta. 3. Computing with Quanta

Part One starts with Alan Turing and his famous exploits at Bletchley Park. It overall once again highlights the fact that at a time when even electronic calculators were sci-fi concepts, Turing was already theorising Artificial Intelligence. The most important aspects of Turing and his contribution to computing has been precisely explained in around 40 pages. Then other scientists specially von Neumann and their story of developing the bed rock of modern computers is brilliantly outlined. The interlude sums up the whole business of classical computing.

Part two is all about Quantum Mechanics and its bizzare concepts. Through the stories of the greatest scientists of the field, with the idea of explaining quantum computing in hindsight, the author outlines the basic debate about the interpretation of how the quantum world explains our reality. This part slowly but steadily brings the reader upto the point where the arena for quantum computing has all been set up. It focuses mainly on Feynman and Bell to take us from rudimentary computers at Los Alamos to modern era of computing with the theoretical foundation of quantum computers.

Part three is where the author finally collapses the wavefunction to give us the first glimpses of what quantum computers are all about. It expalins how and when a quantum computing system is good, bad and ugly. Then we are introduced to Turing's heirs, as the author calls them. These scientists have pulled up quantum computers out of the chalkboard and into the labs. A very detailed description of the advances in the field, the relevant experiments, the various techniques and criteria for a fully functional quantum computers has been put down and explained well.

This is will be accessible to almost any reader but readers familiar with most of the basic science and scientists in the book will enjoy it much more. For me it was a highly energetic wavepacket with all the information to unpack the next revolution in technological advancement.

[Sumit Gouthaman · Rating 2 out of 5]

I am not sure who this book is for...

From the description, it appears that the book is a introductory take on Quantum Computing (since it promises to take the reader from Colossus to Qubits). However, after reading halfway through it, I got a different feeling.

Some parts of the book read like a beginners textbook where the author is trying to explain complex things using plain everyday examples. However, at the same time, the author glosses over some very complex concepts without pausing to explain it to regular readers unfamiliar with quantum theory.

In general, I would not recommend this one to anyone expecting to find a gentle introduction to quantum computing. However, if you already have a strong physics background, you might find this one comfortable to read.

I abandoned this book around midway, since I lost my grasp on the material at that point.

[Stuart Houghton · Rating 4 out of 5]

A very readable and clear guide to the history and future of quantum computing. Gribbin is very good at explaining some mind-bending ideas in relatively plain English and the parts of the book dealing with the personalities involved (Turing, Feynman, Von Neuman, et al) are well researched. The whole thing rattles along much more easily than you might have hoped.

[mistspelt · Rating 3 out of 5]

i understood nothing 😍 literally words on a page.

[Salim · Rating 5 out of 5]

Certainly not the easiest book to read for a complete novice in the field. Speaking as a student in the fields of Physics, Mathematics and Electronics however, it has been a blast, again not the easiest blast, to read this wonderful book : A one-of-a-kind summary to the art of computation from before Turing to the Quantum Theory era. I'd recommend this more as a compass to get introduced to the whole field.

[Dex · Rating 3 out of 5]

3.5

This took me forever to get back to reading, because the first third was kind of boring. I just wish he'd cut to the goddamn chase at times. I didn't need biographies for every single scientist introduced!

Also, he explained some concepts really well, but some went way over my head as he didn't explain other concepts. It's as if he couldn't decide what his audience for this book was- beginners looking for a broad overview/introduction to Quantum Computing, or people with a physics-based background looking into something specific. Some areas he went over very broadly when depth would've been more appreciated. And, enough of the plugs for his other works!!

Overall, an interesting read. I wish he'd gone more in depth about the late third of the book and spent less time on the history of all computers leading up to then.

[Seng Wee Wong · Rating 3 out of 5]

Based on its book name, I expected more from the book. This book took half of its length to introduce the origin of classical computers and then quantum computers. Basically like a history textbook on computers. Well it is great for people with little or no background about the history of computers so you wont get lost when you reach the part about quantum computers.

I didn't know know the full details about how Alan Turing came up with first prototype of the classical computer hence I largely enjoyed the book. It became a story book instead of a technical one I expected. However I would expect most of people reading this book to already have deep insights about computers so they would want to know more about the technical details of quantum computers. The technical part on the quantum computing technology only takes up at most 10% of the book's content.

[Casandra · Rating 5 out of 5]

Highly recommended for anyone who wants to know more about quantum computers. No previous knowledge of conventional computers or quantum physics required to start. That all gets explained in the book. ;)

[Alex Davis · Rating 4 out of 5]

Good introduction to quantum computing. However, the book spent the first third discussing the history of classical computing, which I found unnecessary to the foundations of quantum outside of a brief review of information theory.

[Ruben Merre · Rating 3 out of 5]

By no means a book for beginners, so if you're just starting out with quantum physics / computing, better to read the books by Carlo Rovelli (quantum physics) and "Quantum Computing: The Transformative Technology of the Qubit Revolution", by Brian Clegg as a good starting point.

The book does start off with a great introduction on Alan Turing and contemporaries who contributed enormously to the first computers, code breaking, and eventually everything that followed suit. The level of detail is appreciated.

In the next parts of the book, I'd argue it becomes quite complex and dry for most readers. What could have been a game changer here is the use of actual visuals to explain the different concepts in a more simple manner. Instead, the author explains the dry theory behind concepts such as Nuclear Magnetic Resonance (NMR), ion traps, without making it adequately tangible/concrete for the reader. It makes the explanation hard to follow and I'm sure the author will lose quite a few of his readers here (confirmed by many of the other reviews on this book). It's a bit unfortunate, as with some modifications this could have been a great work. That said, many relevant concepts are touched upon, and can give the reader the nudge to go look them up elsewhere to truly understand them.

In conclusion, instead of (or in addition to) spending great detail on the lives of every physicist involved, it would have been fantastic if the same granularity would have been given on the actual concepts.

[Stella · Rating 3 out of 5]

Never should one see ‘I will not go into detail’ so many times in a non-fiction book with so much of the WRONG detail. The information was astounding to me, when I got past the poor writing. There was too much useless biographical information, not enough scientific explanations. Perhaps this book is just for people with an already very scientifically-orientated mind with prior-knowledge of all this stuff, but the incongruity of the level of some of the information included made the target audience a tad ambiguous to me. I’m glad I read it, but I feel I have come away with only a very vague knowledge on the subject due to the weird structure, lazy sporadic writing, and lack of comprehensive explanations. I don’t like to admit it was confusing, but it was. I just couldn’t get along with the writing style/structure and bald explanations.

[Samuel · Rating 3 out of 5]

Computing with Quantum Cars provides a nice (if brief) summary of the history of quantum computing, but unfortunately is more than a little lacking in its technical discussion. Many explanations rely on a reader having significant prior knowledge, making them difficult to grasp for the laypeople I assumed the book was written for. At the same time, the book also refuses to go into particular details that one may want if they have that background knowledge. As a result I found it mostly unsatisfying, failing to fully succeed in any particular goal. It was not all bad though, and I particularly appreciated 1) the focus on the crytographical history of computing to bind the work together, and 2) what I feel is one of the best basic explanations of Many Worlds Interpretations that I have read.

[Frank · Rating 4 out of 5]

This is an excellent informal introduction to the history of quantum computing through the perspectives of various key players in quantum mechanics, computer science, computation, and quantum physics. John does a great job introducing the history behind computation, from Alan Turing to John von Neumann, from Richard Feynman to John Bell, from David Deutsch to Peter Shor... To truly appreciate where we are today with quantum computing, we must understand where we came from.

I was particularly blown away by the section on the Many Worlds Interpretation of Quantum Mechanics, and the question posed by David Deutsch on explaining how Peter Shor's algorithm works. Definitely planning on reading more books related to this subject.

[Dan Wilcox · Rating 4 out of 5]

I think this book provides the exact answer people are looking for when they ask "what is quantum computing" and "how does it work." While the first two-thirds of the book are very much just trying to keep your head above water in understanding all the concepts, the final part of the book neatly wraps up everything discussed previously in a coherent and sensible manner. How quantum computers actually work is something that only makes sense when all of the physics is explained thoroughly and tied together, providing a very satisfying explanation of the subject.

Of course, it's a really tricky topic and there are plenty of things that I don't understand about it, but if I want to learn more about it in the future I feel confident I'll know where to start.

[Andre W · Rating 4 out of 5]

It’s a tough read - in a good way!
In the beginning I was a bit put off by the extremely historical and slow introduction into the history of quantum physics - but oh boy does it pick up the pace later on!

The last two chapters were particularly difficult to follow, the author certainly tried to explain as much as possible - as simple as possible, but it was still a bit too wild for me. Some really important basics the author did not explain were leaving larger and larger holes in my understanding in the last chapters.

Still - an inspiring book that is all about paying respect where it’s due and it’s less about explaining quantum theory and more about pointing the reader into the right direction for further research.

[Hussam · Rating 4 out of 5]

Spread over three parts, starting from the days of Alan Turing and Johnny von Neumann to the developments in theory of Quantum Mechanics right up to the developments in 21st century when the first humble quantum machines are coming to life, this book takes you on an unbelievable journey. At the heart of it, we start with the need of military to send coded messages and the opposing army to decode it, right up to the modern times when we need to develop machines that produce unbreakable codes to secure our banking transactions for example. We are standing at the brink of quantum computing and it is something that'll be commercialized in our lifetime. That is such an exciting prospect!

[Michelangelo Rubino · Rating 5 out of 5]

The content of this book is extremely valuable for people interested in knowing more about quantum computing. It describes this subject starting with the life of the scientists behind it, Turing, Von Neumann, Feynman... I must admit that I was lost in the last chapter, Turing's heirs, but it is quite technical and I have not a background in physics. The only remark I can make is about the bios of the scientists, sometimes there are too many details, especially in the Part One. Anyway, a great book. Many people will find funny that even Von Neumann made a silly mistake and the first one to spot it was an otherwise unknown woman, Grete Hermann

[Jamie · Rating 4 out of 5]

Gribbin provides an insightful overview of how quantum computing fits into the history of computing generally. In doing so, he provides the reader with a good understanding of how computers work at their basic level.

One thing I found particularly interesting was the discussion of encryption. Gribbin notes that traditional encryption is likely to fare poorly with the advent of quantum computers. However, more sophisticated encryption is made possible through these computers.

An issue with the book was the tendency to spend a large amount of time discussing the biographies of all the relevant researchers. This made it hard to follow the narrative at times.

[Ross · Rating 5 out of 5]

In 2025, this is still an excellent book for a general reader. I read it and then looked up advances since its publication in 2013. Advances since then are scientific, not practical manufacture and use of quantum computers. Therefore, you can safely dedicate time for this book. The author has an intuitive manner for explaining awkward concepts sufficiently and stating clearly when the reason is not known or unimportant for the purpose of introducing them. Quantum concepts are extraordinary and the author is that rare person who does not complicate them further (explainer effect).

[John · Rating 3 out of 5]

For me, I'd say this was a bit lower than a three -- I didn't look enough into what it was.

A lot of time is spent on histories of figures, but that was all stuff I've read before, and it's big overviews.

The time it spends on quantum computing is thus less and at a basic level.

So, if you aren't from a technical background, never heard of this really, and want to get some insight, it could be good.

It wasn't right for me, however.

[Judy Morale · Rating 4 out of 5]

Excellent book, with a good explanation of not just the history of computer science and quantum mechanics but also a detailed explanation on how each discovery worked. However withy the introduction of loads of historical figures with each one having different ideas and perspective it was rather hard to keep track of everyone at times. I wish there would have been a timeline of some sorts or pictures to aid me.