Charles Bennett (left) and Gilles Brassard pose for a photograph next to a cryptography quilt. Credit: Lise Raymond
Gilles Brassard and Charles Bennett have been awarded the A. M. Turing Award “for their essential role in establishing the foundations of quantum information science and transforming secure communication and computing”. The two will share the US$1-million prize, the Association for Computing Machinery in New York City announced on 18 March.
The two winners have seemingly unrelated research backgrounds: Brassard is a computer scientist at the University of Montreal in Canada, and Bennett is a physicist at IBM Research in Yorktown Heights in New York.
This is the first time that the Turing Award, often described as the most prestigious prize in computer science, has recognized work related to quantum physics. Bennett and Brassard — partly through joint work — began to investigate the power of phenomena that could go beyond what’s possible with non-quantum, or ‘classical’, methods of information technology as far back as the 1970s. “People thought it was just a little crazy,” says Bennett. “It didn’t occur to people that quantum effects could be used to do things that couldn’t be done classically.”
Brassard says the accolade made him “extremely happy”. “Had I been asked to choose one recognition at any point in my career, it would have been the Turing Award,” he says.
Bennett and Brassard “played a very big part in establishing the foundations of quantum information”, says Stephanie Wehner, a quantum-communications researcher at Delft University of Technology in the Netherlands. “Quantum information is more than a vehicle for classical information. We can do things with it that don’t have a classical analogue.”
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Bennett and Brassard’s work not only initiated a whole field of technological development, but it also fed back into researchers’ understanding of the Universe, says Jonathan Oppenheim, a theoretical physicist at University College London. Bennett and others have used quantum information as a tool for investigating some of the most nagging problems about black holes, for example. “This whole revolution of quantum information theory is really bringing insights into the physical world,” Oppenheim says.
Quantum encryption
The two winners’ work took inspiration from the late 1960s work of the late physicist Stephen Wiesner. Wiesner had pioneered the idea that the quantum ‘weirdness’ of particles such as photons — which had been seen as a potential nuisance for applications — could be put to good use.
In 1984, Bennett and Brassard developed the first concept of a quantum encryption key1 — one that the sender of a message could share with the receiver in a stream of photons. They showed that any device trying to intercept that stream would destroy the information stored in the photons, thereby revealing that the transmission had been intercepted. Later that decade, Bennett led a team at IBM that first demonstrated technique experimentally.
Another breakthrough came in 1993. Starting from one of Bennett’s ideas, a team comprising Bennett, Brassard and four other researchers developed the concept of quantum teleportation2. It relies on the phenomenon of quantum entanglement, in which two particles share a quantum state even when moved far apart from each other. In teleportation, two entangled particles — one owned by a sender and the other by a receiver — can be used as a conduit to transport quantum information from the sender to the receiver.
