A quantum leap for the Turing Award

Today it is widespread Admit that The future of computing will involve Quantum world. Companies like Google, Microsoft, IBM, and a few well-funded startups are feverishly building quantum computers and routinely claim advances that appear to bring this strange, world-changing technology within reach. In 1979, all of this was unthinkable. But that summer, two scientists met in the Atlantic Ocean off the coast of Puerto Rico, and their watery conversation led to a body of work that created quantum information theory. In a broader sense, their contributions helped bring computer science into the quantum age.

These flooded scientists, Charles Bennett and Gilles Brassard, are now the latest recipients of this award ACM AM Turing AwardNobel Prize in this field.

Until that meeting in 1979, there was a disconnect between information science and physics. The latter field saw disruption in the early 20th century when physicists discovered quantum mechanics, a deeper explanation of how the universe works that replaced Isaac Newton’s classical physics. However, computer science had not taken into account the quantum world, except for having to deal with its effects on microchips, where the behavior of electrons was relevant.

“In the 1950s and 1980s, people thought quantum effects occurred in very small objects and as a source of noise, and you had to understand quantum theory to build transistors,” Bennett explains. “People thought quantum mechanics was a nuisance.” He and Broussard discovered methods, such as quantum coin tossing and Quantum entanglement– which turned the perceived constraints of quantum reality into a powerful tool.

At the time of their meeting, Bennett was at a career crossroads; He joined IBM in 1973, but took a years-long break from academic publishing. One source of continuing fascination was an idea shared by his college classmate, Steven Wisner, that using a quantum form of cryptography could enable digital money that could not be counterfeited. (Yes, Weisner conceived of cryptocurrency in the late 1960s!) At a 1979 conference, Bennett saw that a cryptographer named Brassard was present—who had just completed his thesis on public-key cryptography—and located him abroad.

“I was swimming at the beach when a complete stranger approached me and started telling me that a friend of his had discovered that we could use quantum mechanics to make affordable banknotes out of thin air,” Broussard told me. “If I were on stable ground, I would have run for my life, but I was trapped in the ocean, so I listened politely.” Although Brassard had no prior interest in physics, he was fascinated by the approach, and the duo eventually published a theory called BB84, essentially creating an alternative to classical public-key cryptography based on what later became quantum information theory. Suddenly, the quantum world became a source of solutions, if scientists could invent the mechanisms to make it happen. As Yiannis Ioannidis, president of the ACM, which awards the Turing Prize, said in a statement: “Bennett and Brassard fundamentally changed our understanding of information itself.”

Both scientists are at pains to say that their original work did not directly lead to the current scramble to build quantum computers. Bennett notes that V 1981 conference at MIT, Legendary physicist Richard Feynman has shown that since nature is quantum, it is likely that some computational functions must be performed by a quantum computer. He also credits the physicist David Deutsch For key ideas about quantum computers. Bennett and Brassard became part of that effort.

“Quantum computing was invented independently of us, but then we jumped on it,” Brassard says. “I was the first person to design a quantum circuit to do quantum teleportation.” Brassard and Bennett Work on teleportationAlthough it is still in an experimental stage, it is now part of quantum knowledge. Brassard He said And that “one day, it will fuel the quantum Internet.”