MIT PHYSICS OF COMPUTATION SEMINAR Date: Monday, July 19 Time: 11AM Room: 4-270 Quantum versus Classical Information: a Fruitful Dichotomy Charles H. Bennett IBM Research, Yorktown Heights Abstract: Classical information (the kind in newspapers) and quantum information (carried by certain states of elementary particles such as photons) are very different. Classical information can be read, copied, and transcribed into any medium, but it cannot be sent faster than the speed of light. Quantum information cannot be read or copied without disturbing it, but in some instances can propagate instantaneously or even backward in time. Together the two kinds of information can perform several feats that neither could do alone. These include quantum cryptographic systems, some of which have already been built, in which privacy of communications is guaranteed by the uncertainty principle; and a new technique, "quantum teleportation", by which an unknown quantum state (eg a photon of unknown polarization), can be dismembered into purely classical and purely nonclassical parts, transmitted through separate channels to a new location, and recombined there to produce a perfect reincarnation of the original state. Host: Norm Margolus, MIT Lab for Computer Science This talk is part of a new seminar series on adapting computers and computations to the constraints of, and opportunities afforded by, microphysics; and on the development and application of the physical theory of computation and information. Please forward this notice to anyone who you think might be interested. Anyone who wishes to be added to the distribution list for these seminar announcements should send email to "poc@im.lcs.mit.edu". This series is being sponsored by the MIT Information Mechanics Group (Lab for Computer Science), in conjunction with the MIT Physics and Media Group (Media Lab), the MIT Porous Flow Project (Earth, Atmospheric and Planetary Sciences), and the Mathematical Sciences Research Group at Thinking Machines Corporation.