Chapter 5 Excerpt

Today, on your smartphone, you can access information resources vastly greater than any library. And according to Moore’s law, in a couple of decades your laptop will comfortably hold every single book that has ever been written. A laptop quantum computer will seem more like Jorge Luis Borges’s Library of Babel — a fantastical collection holding every possible ordering of letters and words in a book, and therefore every book that could ever be written. With a quantum library, one might instead be able to search for all possible interesting passages of text without anyone having had to compose them.

Some of the uses of quantum computers and quantum communication are easy to anticipate. Ensuring the security of information is one of them. The codes currently used to protect access to bank accounts, computer passwords, and credit card information rely on the fact that it is hard to find the prime factors of large numbers using a classical computer. However, as Peter Shor showed, quantum computers will be able to quickly find these factors, rendering current security protocols obsolete. Also, quantum information is inherently safer from attack than classical information, because it is protected by the fundamental laws of physics. Whereas reading out classical information does nothing to change it, according to quantum physics, the mere fact of observing a quantum system almost always changes its quantum state. Through this effect, eavesdropping or hacking into quantum information can be detected. Hence quantum information can be made invulnerable to spying in ways that would be classically impossible.

Quantum computers may also transform our capacities to process data in parallel, and this could enable systems with great social benefit. One proposal now being considered is to install highly sensitive biochemical quantum detectors in every home. In this way, the detailed medical condition of every one of us could be continuously monitored. The data would be transmitted to banks of computers which would process and screen it for any signs of risk. The results of any medical treatment or dietary change or any other intervention would be constantly gathered. With access to such vast amounts of data and information-processing power, medicine would be revolutionized. We would all be participants in medical trials, on a scale and with an accuracy and breadth greater than anything seen before.

But by far the greatest impact quantum computers will have is likely to be on ourselves.

Excerpt from pages 223-225 of The Universe Within © 2012 Neil Turok and CBC.

No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.