סמינר קוואנטום: Stephen Wiesner (1942-2021) and the birth of quantum information
Prof. Charles H. Bennett, Thomas J. Watson Research Center, Yorktown Heights, NY USA
The ongoing information revolution grew out of two discoveries made at Bell Laboratories in 1948. One was the transistor, which launched decades of amazing miniaturization of electronics.
The other was Claude Shannon’s revolutionary paper on information theory. Nowadays even non scientists understand the gist of it: anything one wishes to communicate—words, sounds, pictures, shapes, movements and maybe someday even smells—can be coded into zeros and ones, transmitted through a noisy channel such as radio or optical fiber to a remote location and then reassembled into an arbitrarily good approximation of the original.
Twenty years later, Stephen Wiesner noticed that quantum effects could be used to do some intriguing things not covered by Shannon's theory, for example combining two messages into a single transmission from which the receiver could easily recover either one, but not both. Wiesner made little effort to publish or publicize these ideas, but he did tell a few friends, including me and my longtime collaborator Gilles Brassard. From my conversations and correspondence with Wiesner during the critical period around 1970, I will try to trace the path by which he discovered the no cloning principle, entanglement-assisted communication, and, almost, the subtle no-go theorem for bit commitment. These became the foundation of today's simpler and grander mathematical theory of communication. Though Wiesner overlapped temporally with Shannon at MIT, I don't think they ever interacted. Too bad—it might have reawakened Shannon's interest in the field he founded.