From Barnes & Noble
Computers are constantly becoming smaller, faster, and more potent. But the power of even tomorrow's supercomputers could be dramatically outstripped by the development of quantum computers now on the drawing boards. In A Shortcut Through Time, award-winning New York Times science writer George Johnson guides us on a mind-boggling tour of the miraculous world of nanosecond computation.
The New York Times
George Johnson has written a blessedly slim book, A Shortcut Through Time, that gets across the gist of quantum computing with plenty of charm and no tears. Computer science is hard; quantum mechanics is weird. But Johnson, who contributes science articles to The New York Times and is the author of four previous popularizations, explains it all with Tinkertoys and clocks and spinning tops and just a little arithmetic. It's a briskly told story, driven entirely by ideas. — Jim Holt
Publishers Weekly
Johnson has been nominated for several awards for earlier books on physics and physicists (Strange Beauty; Fire in the Mind). Here he sticks mainly to science, providing a quick overview of a cutting-edge union between quantum theory and computing. The book begins by describing a computer as "just a box with a bunch of switches." Although today's computer switches are imbedded in circuitry, they can in principle be made of any material, like the early banks of vacuum tubes; Johnson also recalls a tic-tac-toe-playing machine created from Tinkertoys in the 1970s. An ordinary computer switch, binary in nature, registers as either a zero or a one, but if a single atom were harnessed as a switch, its dual nature as both particle and wave means it could be "superpositioned," simultaneously zero and one. A series of such switches could handle complex calculations much more swiftly than conventional computers: an entertaining theory, but impractical. Except that a quantum computer's ability to factor large numbers-determining the smaller numbers by which they are divisible-would have a critical application in cryptography, with a string of atoms used to create (or break) complex codes. After discussing competing projects that aim to make the theory of quantum computing a reality, the book concludes with ruminations on the implications of the projects' possible success. Using "a series of increasingly better cartoons" and plain language, Johnson's slim volume is so straightforward that readers without a technical background will have no problem following his chain of thought. Illus. Agent, Esther Newberg. (Mar. 2) Copyright 2003 Cahners Business Information.
Library Journal
The simplicity of binary logic, on or off, 1 or 0, is what enables today's desktop and supercomputers to process data. Quantum computing, on the other hand, operates under a different set of rules in which everything is 1, 0, or 1 and 0 at the same time. Here, Johnson, an award-winning science writer for the New York Times and author of Strange Beauty: Murray Gell-Mann and the Revolution in Twentieth-Century Physics, chronicles a technology that on its deepest level he even finds "hard to swallow." Advances in quantum theory are as inevitable as the universe's expansion, he posits, and they will result in exponentially faster computers that will be able to solve complex problems now considered impossible. In everyday terms, quantum computers would be able to search infinitely vast databases in mere seconds or solve mathematical problems that have puzzled scientists for centuries. On the dark side, Johnson warns that a quantum computer in the hands of a digital thief could be used to crack complex encryption codes that protect credit card transactions and other sensitive financial information or compromise the security of classified military information. Johnson has presented the fascinating science of quantum computing and its future development in a down-to-earth style. Recommended for most libraries. [Previewed in Prepub Alert, LJ 10/1/02.]-Joe J. Accardi, Harper Coll. Lib., Palatine, IL Copyright 2003 Reed Business Information.
Kirkus Reviews
New York Times science writer Johnson (Strange Beauty, 1999, etc.) explains why quantum computers are expected to be the next major breakthrough. The author begins by recalling his youthful disappointment when he received a build-it-yourself computer and discovered how simple it was. But that anticlimax revealed a central truth: all digital computers are in essence bundles of on-off switches. The logical destination of the trend toward miniaturization is a computer in which each switch is a single atom. There is more to the quantum computer, however, than mere compactness, as Johnson makes clear in a quick summary of quantum theory. The beauty of the "qubit" (as scientists have dubbed the quantum bit) is that it can be in several superimposed states: not just "on" or "off," but both at once. Thus, the numbers 1 through 1024 can all be represented at once by ten quantum switches. Put into practice, this capability enables a stunning increase in speed, essential for tackling such problems as the factoring of very large numbers, which is a key to modern cryptography. Johnson spends some time examining ways in which the simple switches that are the basis for computers could be built from quantum parts. He doesn't minimize the difficulties of the task. To give just one example, capturing atoms (or molecules, or subatomic particles) and training them to act as switches requires cooling them close to absolute zero, impractical for desktop applications. Nor are the qubits anywhere near as stable as one would like, with a few seconds the best working lifetime so far achieved. Still, the potential of the nascent technology is fascinating, and if successful, its development is likely to be one ofthe most closely watched scientific stories of the new century. A tantalizing glimpse of how the uncertainties of quantum theory may yet be tamed for work of the highest precision.
