Physics of computing

Ron Resnick (
Tue, 20 May 1997 16:45:49 +0300 (EET DST)

A followup to recent discussions of physics analogies to computing
(eg Climbing Clueful Mountain and Ernie's rebuttal - Physics of Objects).



Bennett Elected to the National Academy of Sciences Charles H. Bennett, IBM Fellow, systems, technology and science, Thomas J. Watson Research Center, has been elected to the National Academy of Sciences (NAS). Election to the Academy is considered one of the highest honors that can be awarded to an American scientist or engineer. Bennett is recognized worldwide for his contributions to the fundamental understanding of the relationship of physics to computation and communication. In his work on reversible computation, Bennett demonstrated that the energy dissipation in computation -- which had previously been traced to the discarding of information -- could be made arbitrarily small provided no information was discarded at any step and the computation was done slowly enough. In addition, he has resolved the famous demon paradox posed by Clerk Maxwell in 1867. By observing the random heat motion of molecules, the demon could separate the fast-moving ones and use them to do useful work, which would be a contradiction of the second law of thermodynamics, were it not for the additional work the demon must do to erase its memory of which molecules were fast moving. Bennett along with Gilles Brassard of the Universite de Montreal, invented quantum crptography, which uses the uncertainty principle to protect secret messages from eavesdropping. He is also one of the framers of the concept of quantum teleportation, where the exact quantum state of a particle such as a photon or atom can be disembodied from that particle and reincarnated in another particle that has never been near the first particle. The NAS is a private organization of scientists and engineers dedicated to the furtherance of science and its use for the general welfare. The Academy was established in 1863 by a congressional act of incorporation, signed by Abraham Lincoln, that calls on the academy to act as an official adviser to the federal government, upon request, in any matter of science or technology.