Seminário de Computação e Informação Quântica 

01/07/2005, 15:00 — 16:00 — Sala P4.35, Pavilhão de Matemática
Gilles Brassard, U Montréal

The Spooky Power of Quantum Entanglement

Entanglement is perhaps the most nonclassical of all quantum resources. It allows for otherwise impossible tasks, such as quantum teleportation. Nevertheless, entanglement by itself cannot be used to signal information between two parties or even reduce the number of classical bits that must be transmitted to communicate any given message between those parties. In apparent contradiction, there are distributed computational tasks that can be accomplished with exponentially less classical communication in the presence of entanglement, compared to the best possible all-classical protocol. Even more remarkably, there are distributed tasks that cannot be accomplished at all in a classical world when communication is not allowed, but that become possible if the non-communicating parties share prior entanglement. A real-life implementation of this phenomenon, known as pseudo-telepathy, would offer perhaps the most convincing evidence that we do not live in the kind of world that Einstein was dreaming to build. No previous knowledge of quantum mechanics will be assumed.