* George Johnsons A SHORTCUT THROUGH TIME could be subtitled
"A Beginners Guide To Quantum Computing and Cryptography", with
this book exploring the bizarre quantum phenomena that could,
in potential, be used to perform computations on a range of
numbers simultaneously, or produce ciphers that are literally
impossible to crack by analytical means.Trying to say more about the concepts discussed in this book
in a short review is impossible -- explaining how a particle
will simultaneously exist in all its possible states at once
until its measured will give either a blank stare or a bland
"yeah right I know", meaning it didnt really register -- but
it isnt necessary, because Mr. Johnson does a right nice job
of explaining such matters in this neat brief book.
His writing is extremely clear and concise, at least relative
to the difficult matters he is discussing, and the book is
tidily illustrated. This is, to be sure, a book for beginners,
and in fact it spends some time up-front explaining basics
of computers before it moves on to quantum effects. A
specialist will likely have NO use for it, and might even be
a bit scornful at Mr. Johnsons occasional excursions into
arm-waving.
In fact, I did have some real problems with his discussions
of Shors and Groves quantum-computing algorithms, when
Mr. Johnson did seem to be getting into some real arm-waving.
Well, given the difficulty of the material, he was likely to
fall into that trap in places, and maybe I should just give
him the benefit of doubt, read that material again a few times,
and sleep on it.
However, I was basically familiar with quantum computing and
cryptography (at a layman level) before I read this book, and
at the outset thought it might not tell me anything I didnt
already know. I was wrong since I got a tidy explanation of
the application of quantum teleportation to cryptography
(blank stare out there?), and some other nice tidbits.
Besides, I was thoroughly impressed by Mr. Johnsons
sensibility in his comments about technical writing and his
degree of cautious skepticism in dealing with physicists, some
of whom seem to be slightly around the bend. The late Dick
Feynman, who plays a part of sorts in this book, could
actually understand what the such sorts were saying and
nail them, but the rest of us will just have to sympathize
with Mr. Johnson when he makes comments such as:
"Gilles Brassard tells me that each dim flash, on the average,
contains perhaps one-tenth of a photon, an idea I find rather
difficult to grasp."
You just gotta like this guy.
Brain Freeze