Computer Science’s “Nobel Prize” Goes Quantum

The biggest prize in computer science, the A.M. Turing Award, has for the first time honored work in the quantum realm.

Bennett and Brassard have prepared the groundwork for the much-anticipated quantum revolution. (Photo: IBM / Lëa-Kim Châteauneuf) 

This year, Charles Bennett, a physicist at IBM, and Gilles Brassard, a computer scientist at the University of Montreal, share the $1 million award for “their essential role in establishing the foundations of quantum information science,” according to the Association for Computing Machinery, Science reported.

Sometimes called the Nobel Prize of computer science, the 60-year-old Turing Award has honored multiple technological advances that are now ubiquitous, such as the internet and the World Wide Web.

In contrast, a full-fledged quantum computer does not yet exist. Nevertheless, Bennett and Brassard have prepared the groundwork for the much-anticipated quantum revolution, says Ueli Maurer, a computer scientist at ETH Zürich.

“It’s the intellectual foundation: How can we exploit quantum effects?” he says.

Harry Buhrman, a computer scientist at the University of Amsterdam who works on quantum computing, says the award winners “had the spark of this idea that turned into this quantum fire we’re in now.”

Ordinary computers work by flipping microscopic electrical switches called bits to signify a 0 or a 1. In contrast, a quantum computer or system manipulates qubits that have well-defined quantum states, such as a photon that can be polarized horizontally, vertically, or both at once.

Unlike a bit, a qubit can be set to 0 and 1 at the same time—at least until it is measured, when it collapses randomly to either 0 or 1. In addition, two qubits can share a mysterious link called entanglement.

When qubits are entangled, the state of each one is uncertain—both 0 and 1—but the particles’ states are correlated. For example, two quantum particles can be entangled so that if one is measured and collapses, say, to 1, the other is certain to collapse the same way.

Bennett and Brassard were among the first to explore how such quantum phenomena could be used to encode and transmit information.