And What, for That Matter, is Information?
Computers of every shape and size mediate our conversations, transmit our news, and play our music. Whatever "information" may or may not be, at least we know where it lives: in the enormous expanses of zeros and ones that form the memories of our myriad digital toys.
Or does it? Canada Research Chair Patrick Hayden is carrying out research that focuses on those types of information that, while apparently permitted by Nature, are not currently supported by Microsoft or (for that matter) anyone else.
Many modern technologies - from lasers to superconducting magnets - owe their existence to a set of physical principles known as quantum mechanics. Nonetheless, because these principles introduce an element of randomness into physical law, until recently most people thought of quantum mechanics as an impediment to the development of nanoscale information technologies - as a source of noise and uncertainty rather than as a source of new ideas and possibilities.
That pessimistic view has been dealt two crucial blows, however: first, by Bennett and Brassard's discovery that the physics of quantum mechanics make possible some cryptographic tasks that would otherwise be impossible, like sharing secret keys; and later, by Shor's discovery that an intrinsically quantum-mechanical computer could efficiently factor large integers and thereby crack a good fraction of the codes used by banks, governments, and Internet users around the world.
In his research as Canada Research Chair in the Physics of Information, Patrick Hayden is developing new ways to manipulate this quantum information at the very limits of what is permitted by the laws of physics, in order to find new applications in cryptography, communications, and computing. His aim is to help make a quantum computer a reality and, ultimately, to better understand the nature of information in the physical world.